WO2017147384A1 - Milieu particulaire préparé à partir de matière organique partiellement décomposée pour sorption sélective entre des ions métalliques en compétition dans des solutions aqueuses - Google Patents

Milieu particulaire préparé à partir de matière organique partiellement décomposée pour sorption sélective entre des ions métalliques en compétition dans des solutions aqueuses Download PDF

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WO2017147384A1
WO2017147384A1 PCT/US2017/019302 US2017019302W WO2017147384A1 WO 2017147384 A1 WO2017147384 A1 WO 2017147384A1 US 2017019302 W US2017019302 W US 2017019302W WO 2017147384 A1 WO2017147384 A1 WO 2017147384A1
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Prior art keywords
peat
cations
granule
aptsorb
granules
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PCT/US2017/019302
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English (en)
Inventor
Igor V. Kolomitsyn
Peggy Wallgren JONES
Douglas A. Green
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American Peat Technology, Llc
Regents Of The University Of Minnesota
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Priority claimed from US15/052,403 external-priority patent/US10173213B2/en
Application filed by American Peat Technology, Llc, Regents Of The University Of Minnesota filed Critical American Peat Technology, Llc
Publication of WO2017147384A1 publication Critical patent/WO2017147384A1/fr

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/30—Processes for preparing, regenerating, or reactivating
    • B01J20/3078—Thermal treatment, e.g. calcining or pyrolizing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
    • B01J20/04—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising compounds of alkali metals, alkaline earth metals or magnesium
    • B01J20/043—Carbonates or bicarbonates, e.g. limestone, dolomite, aragonite
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/22—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising organic material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/30—Processes for preparing, regenerating, or reactivating
    • B01J20/3028—Granulating, agglomerating or aggregating
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/30—Processes for preparing, regenerating, or reactivating
    • B01J20/3085—Chemical treatments not covered by groups B01J20/3007 - B01J20/3078
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/28—Treatment of water, waste water, or sewage by sorption
    • C02F1/286—Treatment of water, waste water, or sewage by sorption using natural organic sorbents or derivatives thereof
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/28—Treatment of water, waste water, or sewage by sorption
    • C02F1/288—Treatment of water, waste water, or sewage by sorption using composite sorbents, e.g. coated, impregnated, multi-layered
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2220/00—Aspects relating to sorbent materials
    • B01J2220/40—Aspects relating to the composition of sorbent or filter aid materials
    • B01J2220/48—Sorbents characterised by the starting material used for their preparation
    • B01J2220/4812—Sorbents characterised by the starting material used for their preparation the starting material being of organic character
    • B01J2220/485—Plants or land vegetals, e.g. cereals, wheat, corn, rice, sphagnum, peat moss
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/10—Inorganic compounds
    • C02F2101/20—Heavy metals or heavy metal compounds
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
    • C02F2103/10—Nature of the water, waste water, sewage or sludge to be treated from quarries or from mining activities

Definitions

  • This invention relates generally to particulate sorption media prepared from partially decomposed organic matter like peat, and more specifically to granules made from such material that are thermally activated and chemically modified to provide them the requisite hardness and sorption capacity for selective sorption of competing metal ions found in aqueous solutions like waste or mine waters.
  • a "solution” represents a mixture of two or more individual substances that cannot he separated by a mechanical means, such as filtration.
  • a liquid solution occurs when a liquid, solid, or gas solute is dissolved in a liquid solvent.
  • the liquid solution constitutes an aqueous solution if the solvent is water.
  • Wastewater streams very often constitute aqueous solutions containing one or more contaminants.
  • Non-chemical treatments of wastewater generally employ a mechanism known as "sorption.” Sorption can involve both chemical and physical processes, but the end result is the transfer of a substance from one phase to another. In other words, sorption is the movement of toxins and contaminants from the dissolved, aqueous phase to the surface of a solid media.
  • sorption is the movement of toxins and contaminants from the dissolved, aqueous phase to the surface of a solid media.
  • Three different types of sorption predominate wastewater treatment technology ion-exchange, absorption, and adsorption.
  • Iorz exchanbe is a separation process widely used in the food and beverage, hydrometallurgical, metals finishing, chemical and petrochemical, pharmaceutical, sugar and sweetness, ground and potable water, nuclear, softening and industrial water, semiconductors, power, and many other industries.
  • Aqueous and other ion-containing solutions can be purified, separated, and decontaminated by swapping targeted ions contained in the solution with substitute ions typically provided by inn exchange resins or other substrates.
  • ion exchange is also a proven technology for removing dissolved metals or other impurities from these wastewater streams. It represents a reversible process in which the ionized metal or other impurity compound or element changes place with another ionized compound or element on the surface of a medium like an ion exchange resin. Ion exchange can produce high-purity water (including softening, deionizing, water recycling, and removal of heavy metals) from the wastewater.
  • an ion exchange-based water softener works by passing hard water naturally containing an abundance of calcium and magnesium cations through a volume of resin beads containing sodium ions on their active sites. During contact, the calcium and magnesium cations will preferentially migrate nut of solution to the active sites on the resin, being replaced in solution by the available sodium ions. This process reaches equilibrium with a much lower concentration of calcium and magnesium cations in solution, thereby "softening" the water.
  • the resin can be recharged periodically by washing it with a solution containing a high concentration of sodium inns, such as a sodium chloride solution.
  • Synthetic inn exchange resins are typically used within ion exchange processes. These synthetic resins commonly are formed of small 0.03 - 2.0 mm beads made from an organic polymer substrate, such as cross-linked styrene and divinylbenzene copolymers. Moreover, these resin beads will feature a highly developed structure of pores on the surface of the resin, which provide the sites for trapping and releasing ions. These resin beads can be converted to cation-exchange resins through sulfonation, or to anion- exchange resins through chloromethylation.
  • a prefiltration unit in the form of activated carbon or other separation material may need to be positioned upstream of the ion-exchange unit to remove these organic contaminants before the wastewater is passed through the ion exchange resin, further complicating the water treatment process and its costs. The costs associated with this pretreatment can be substantial.
  • resins require regeneration once the ion-exchange sites have been exhausted, for example, as feedwater flows through a bed. During regeneration of a cationic resin, metal cations that were previously adsorbed from the wastewater flow, are replaced on the resin beads by hydrogen ions.
  • a step known as ⁇ backwash" is often employed during regeneration, so that any organic contaminant buildup in the resin can be relieved, thereby allowing free flow of the wastewater through the resin beads.
  • chemically-regenerated ion-exchange processes known in the art tend to use excessive amounts of regeneration chemicals, which require periodic and even on-going treatment, as well as safe disposal of the chemical waste. These processes can be complex and expensive to operate.
  • Another "sorption” separation process is absorption. This is a physical or chemical phenomenon or process in which atoms, molecules, or ions enter some bulk phase, whether it be a gas, liquid, ar solid material. The gas, liquid or solid material takes in the other substance, like a sponge soaking in water.
  • absorption is necessarily limited by the physical capacity of the absorbent substrate, and can require Frequent purges of the taken-up substance to replenish the absorbent capacity of the substrate.
  • adsorption This represents a process in which atoms, ions, or molecules from a gas, liquid, or dissolved solid adhere to the surface of a substrate. This constitutes asurface-based separation process, instead of absorption which involves the whole volume of the substrate material.
  • certain adsorbates in the adsorption process are selectively transferred from the fluid phase to the surface of insoluble, rigid particles.
  • Activation is the process of treating a material that is high in carbon for purposes of increasing surface area and creating porosity.
  • Materials can be activated either with chemical treatment followed by a thermal step, or with heat treatment alone.
  • carbon materials that have been activated then undergo further chemical treatment in order to change the activity of the surface of the carbon-based material.
  • Activated carbon substrates have been employed in the water filtration industry for this adsorption separation process. Unlike synthetic polymer resins used in ion exchange processes, these activated carbon materials constitute a form of carbon that has been processed to snake it extremely porous with a resulting very large surface area for adsorption of impurities via van der Waals forces or London dispersion forces, or chemical reactions.
  • activated carbon substrate Due to its high degree of microporosity, just one grain of activated carbon substrate can provide a surface area exceeding 500 m2 (about one tenth the size of a football field). Moreover, such activated carbonaceous materials can be produced Crom a variety of natural organic materials like vegetable matter, soft woods, cornstalks, bagasse, nut hulls and shells, various animal products, lignite, bituminous, or anthracite coals, straw, petroleum pitch, or peat. Chemical ⁇ lctivc ⁇ tion
  • Carbonaceous material may be chemically activated by impregnating it with an acid, strong base or a salt like phosphoric acid, sulfuric acid, potassium hydroxide, sodium hydroxide, calcium chloride, or zinc chloride, followed by carbonization via pyrolysis at a high 450-900 °C temperature range.
  • peat can be impregnated with phosphoric acid or zinc chloride mixed into a paste, and then pyrolyzed at 500-800 °C to activate the peat, followed by washing, drying, and grinding this chemically activated peat into a powder to produce activated carbon having a very open porous structure that is ideal for adsorption of large molecules.
  • Russian Published Patent Application No.1,142,160 filed by Sokolov et al. discloses an active adsorbent product made from aluminum salt sludge. Organo- aluminum sludge produced in the process of coagulation of aluminum salts in water is thickened to create a concentration of 10-17%.
  • the aluminum hydroxide fraction is used to precipitate out the organic compounds during a process that is called coagulation.
  • the aluminum hydroxide and organic compounds are then treated with sulfuric acid, and then the solid phase is heated at 210-270 °C for 2-4 minutes. This process destroys the organic material to convert it into activated carbon, and some portion of organic material is reacted with sulfuric acid to produce sulfonic acid derivatives.
  • the end product is used to remove organic compounds and metal cations (e.g., nickel and cobalt) from waste water.
  • carbonaceous materials such as coconut hulls or bamboo can be physically activated by exposing the material to an oxidizing atmosphere like carbon dioxide, oxygen, or steanl at a very high temperature falling within the 650-1200 °C range.
  • an oxidizing atmosphere like carbon dioxide, oxygen, or steanl at a very high temperature falling within the 650-1200 °C range.
  • Polymer resin, acetylene coke, or pearl cellulose are dried at 250-300 °C. Then
  • Giebelhausen carbonizes his material at a very high 850-880 °C temperature without steam. Finally, he thermally activates his carbon pellet product at an even higher 910- 915 °C temperature in a hot gas-tired kiln. Steam is used by Giebelhausen merely to prevent explosions.
  • U.S. Published Application 2003/0041734 filed by Funke et al. shows a method for producing an ultra-low emission (“ULE”) carbon material.
  • U.S. Published Application 2003/0041734 filed by Funke et al. shows a method for producing an ultra-low emission (“ULE”) carbon material.
  • U.S. Published Application 2003/0041734 filed by Funke et al. shows a method for producing an ultra-low emission (“ULE”) carbon material.
  • U.S. Published Application 2003/0041734 filed by Funke et al. shows a method for producing an ultra-low emission (“ULE”) carbon material.
  • Pyrolysis is related to activation in that material high in carbon content is exposed to heat. Activation often involves pyrolysis, but the end result is to produce a product with increased surface area. Pyrolysis constitutes the decomposition of organic material through heating, and it occurs in an oxygen-free environment.
  • Peat is a substance that can be pyrolyzed, and comparative studies of the pyrolysis kinetics for coal and peat have been performed. See Durusoy et al., "Pyrolysis Kinetics of Blends of Gediz Lignite with Denizli Peat,” L'nerbry Soi ⁇ ces, vol.23, pp.393-99 (2001). But, no particular temperature ranges for pyrolysis were determined in this study, nor was any ion-exchange medium prepared. Common uses ofActivc ⁇ ted Carbon
  • Activated carbon filters are popular for home and small-volume water purification systems, because of the adsorbency of the carbon substance.
  • Activated carbons are known to have a heterogeneous pore structure, which is classified as microporous (diameter of pore ⁇ 2 nm), mesoporous (diameter of pore between 2-50 nm), and macroporous (diameter of pores > 100 nm).
  • Activated carbons have a large adsorption capacity, preferably for small molecules, and are used for purification of liquids and gases. Volatile organic chemicals found in the water are removed via adsorption.
  • activated carbon filters are generally not successful in removing dissolved metals like antimony, arsenic, barium, beryllium, cadiniurn, chromium, copper, mercury, nickel, and selenium from the water.
  • the purification efficiency of activated carbon filters is directly influenced by the amount of carbon contained in the filter unit, the amount of time that the water-borne contaminant spends in contact with the carbon, and the contaminant particle size.
  • activated carbon filters must necessarily contain very large carbon volumes treating very low water- flow rates, which makes them
  • a sorption medium from a natural, organic material.
  • a balance must be struck between the physical integrity of the form of the sorption medium versus the ability of the medium to serve as an ion- exchanger, adsorbent, or absorbent.
  • Partially decomposed organic starling material like peat inherently possesses ion-exchange and adsorbent characteristics.
  • Peat is composed mainly of marshland vegetation, trees, grasses, fungi, as well as other types of residual organic material such as insects and animal remains, and is inhibited from decaying fully by acidic and anaerobic conditions. It is also abundant in many places in the world.
  • U.S. Patent No.6,455,149 issued to Hagen et al. discloses a process for producing peat pellets from an admixture of peat moss, pH adjusting agent, wetting agent, and other processing additives. The resulting granules can be easily broadcast spread on the ground, and returned to their original peat moss form upon wetting to act as a fertilizer.
  • U.S. Patent No.5,624,576 issued to Lenhart et al. illustrates pellets made from leaf compost, which are then employed to remove pollutants from storm water.
  • U.S. Patent No.6,143,692 issued to Sanjay et al. discloses an adsorbent made from cross-linked solubilized humic acid, which can be employed for removing heavy metals from water solutions.
  • U.S. Patent Na 6,998,038 issued to Howard contains a detailed disclosure of a storm water treatment system for which the filtering media can include peat.
  • U.S. Patent No.6,287,496 issued to Lownds shows a process for preparing peat granules using a binder and gentle extrusion. In U.S.
  • Patent No.5,578,547 issued to Summers, .ir. et al., a mixer machine and process for producing peat beads for adsorption of metal cations at dilute concentrations ( ⁇ 10 ppm) is disclosed.
  • polysulfone/methylene chloride binder are fed to the mixer to form a pellet, followed by drying.
  • This binder chemical acts like a glue to fuse the peat fibers together in order to create a stronger peat pellet.
  • Summers and others fail to disclose or suggest any thermal activation process step, nor to demonstrate the selective removal of cadmium ions from wastewaters in the presence of high concentrations of zinc ions. See also U.S. Patent No.5,602,071 issued to Summers, Jr. et al. Russian Patent No.2,116,128 issued to Valeriy Ivanovych Ostretsov teaches a process for producing a peat sorbent useful for removing oil spills fi ⁇ om solid and water surfaces.
  • the peat material is dried from 60% moisture to 23-25%moisture, and then compressed at 14-15 MPa pressure into briquettes. Next, these peat briquettes are heated at 250-280 °C without the use of additional hydrophobic chemicals and without air.
  • the humic and bitumen fractions within the peat mobilize to the surface of the peat briquettes to produce a natural hydrophobic coating. This hydrophobic coating is necessary for the peat briquettes to be able to soak up oil. Ostretsov also reduces the moisture of his heat- treated peat briquettes all the way down to 2.5-10% wt. moisture.
  • His peat under this patent disclosure is milled at low decomposition and dried to 20-48% moisture, and then compressed under pressure at a force below 10 MPa, and then heated under a carbon dioxide blanket without oxygen for 20-90 minutes "at a temperature of 15-30 °C above the exuding temperature ofwater-insoluble resins of the carrier.”
  • Ostretsov's process will produce a hydrophobic coating on the surface of his peat material, which is the opposite of the hydrophilic surface that is required for adsorption of metal cations from wastewater streams.
  • Peat is a substance that can be pyrolyzed, and comparative studies of the pyrolysis kinetics for coal and peat have been performed.
  • nitric acid or sulfuric acid is added to neutralize the amine to chemically modify the peat to increase its cation exchange sites by either adding 503- groups to the peat surface structure, or to oxidize the organic carbon to improve the cation exchange capacity.
  • the peat residue maybe treated to asemi-coking process step at 200-1000 °C at a 40 psi pressure, thereby allowing carbonization of peat residue. This will actually destroy the carbon ⁇ bers.
  • Allen actually c1 ⁇ emically Ynoclifies his peat product to increase the cation exchange sites, followed by chemically czctivciting it to increase hydrophobic adsorption properties.
  • U.S. Patent No.6,042,743 issued to Clemenson discloses a method for processing peat for use in contaminated water treatment. Clemenson mixes raw peat with heated sulphuric acid to produce sulfonated peat slurry. After cooling and drying the slurry admixture to a 60-70% moisture content, he adds a binder like bentonite clay to coagulate the acidic peat slurry, extrudes pellets, and then bakes the sulfonated peat pellets in an oven at 480-540 °C.
  • This baking step drives off the moisture, but it also destroys the carboxylic acid (COON) groups.
  • His chemical activation of the peat material via the sulfonation step adds sulfonate groups (-503 -) to the resulting peat granules.
  • Cleinenson's peat pellets adsorb metals by attaching the metal cations to the sulfonic groups due to their opposite charged states.
  • Clemenson cl ⁇ iemically modifies the surface of peat, but failed to preserve carboxylic groups (COOH) that naturally occur in peat.
  • his invention is lacking of any evidence of improving selectivity to sorb cadmium cations from wastewater in the presence of zinc cations. See also U.S.
  • U.S. Patent No.5,314,638 issued to Morine discloses a chemically modified peat product that can be used as an ion-exchange material.
  • This peat material is air dried and milled to a size of one mm or less; hydrolyzed in an aqueous hydrochloric acid solution to remove the soluble components (sulfuric acid and nitric acid may also be used); further treated in an extractor with 2-propanol/toluene solvent to remove the solvent-soluble bitumen; dried to remove the residual solvent; and then immersed in a hot concentrated sulfuric acid bath at 100-200 °C for 1-4 hours.
  • the hot sulfuric acid bath process step comprises chemical modification in which the sulfuric acid reacts with the peat fibers to add sulfonate anions (5030 to its surface. These anions within the ion-exchange resin attract metals via chemical attachment.
  • Various efforts have been made within the industry to use granulated and dried peat material as a cation exchange media. More particularly, Soviet Published Patent Application No.806,615 filed by Peter Illarionovich Belkevich et al. produces a water Ater product from pellets comprising a paste made from peat and a precipitate of neutralizing etching solution. This paste and the resulting pellets are produced without any physical activation treatment.
  • Belkevich uses his neutralising etching solution like a glue to hold the peat fibers together in a pellet and therefore obtain the desired granule hardness. Furthermore, Belkevich employs his peat pellets as a filter to remove non-ferrous metals like copper and zinc and petrochemical products from waste water. It is unclear that Belkevich's peat pellets are acting as an inn-exchange material. Challenges faced By Peat and Other Natural. Organic Materials
  • peat has low
  • peat and other organic starting materials suffer from a number of other problems that compromise their utility as a sorption medium.
  • prior art activation steps like pyrolysis can cause these materials to lose their ion-exchange capacity.
  • Carbonization may cause considerable shrinkage and weight loss of the materials, as well as loss of natural adsorption properties toward metal ions.
  • Organic sources also generally suffer from non-uniform physical properties.
  • Naturally-occurring organic ion exchange media are unstable outside a moderately neutral pH range.
  • a process for preparation of a granulated or pelletized sorption medium from a partially decomposed organic material like peat, followed by low-temperature thermal activation of the sorption medium to produce a high degree of granule or pellet hardness balanced against an efficacious level of ion-exchange and adsorption capacity, followed by chemical treatment of the sorption material via a preselected solution of soluble salts to increase the availability of naturally-occurring active sites in the granules or pellets to enhance their ion-exchange, complexation, chelation, and adsorption performance to an aqueous solution is provided by this invention (called "APTsorb II*M").
  • the preselected cations from the solution of soluble salts placed on the active sites of the partially decomposed organic material in the sorption medium will alter the coefficient that defines the equilibrium and increase the adsorption capacity more in Iavor of adsorption of more-toxic metals found in the waste water at the expense of less- toxic metals found in higher concentrations in the waste water. This allows the end user to target the more-toxic metals for adsorption by the sorption medium containing the cations contributed by the preselected solution of soluble salts.
  • the resulting APTsorb II*M peat granules exhibit a number of beneficial properties when used in a wastewater treatment process where competing toxic metal cations are present in the wastewater.
  • the granules exhibit a selectivity a of a first type of more-toxic metal cations (such as cadmium, lead, copper, or other metals at high concentrations) over a second type of less-toxic metal cations of (such as zinc, aluminum, or iron); greater adsorption activity for the first type of more-toxic metal cations; and greater
  • the sorption medium of this invention can be used in a variety of aqueous solution treatment processes, such as wastewater treatment for• removing heavy metal constitutes via ion-exchange and complexation mechanisms, and also reducing the levels of manganese, iron, and other naturally-occurring metals found in the peat substrate from leaching back into the waste water.
  • Figure 1 represents a schematic view of the portion of the process for preparing the thermally activated peat granule.
  • Figure 2 represents a schematic view of the portion of the process for chemically treating the thermally activated peat granule by means of an acid solution followed by a salt solution to reduce the presence of unwanted minerals within the peat complex, while increasing the sorption capacity and activity of peat granules.
  • Figure 3 represents a schematic view of the portion of the process ofthe present invention for preparing the thermally activated peat granule and chemically treated peat granules that exhibit high selectivity to sorb cadmium cation in the presence of zinc cation (APTsorb II*M).
  • Figure 4 represents a graphical depiction of comparative adsorption data for different metal cations contained in aqueous solutions for the non-chemically treated, thermally-activated peat granules (APTsorb II) and its chemically-treated counterpart material (APTsorb III).
  • Figure 5 represents a graphical depiction of the cadmium adsorption from an effluent aqueous solution stream containing only cadmium cations using an APTsorb III sorption medium.
  • F igure 6 represents a graphical depiction of the cadmium and zinc adsorptions from an effluent aqueous solution stream containing both cadmium and zinc cations using an APTsorb III sorption medium.
  • Figure 7 represents a graphical representation of selectivity coefficient to sorb cadmium cations in the presence of zinc cations from aqueous solution containing both cadmium and zinc cations using a different metal-loaded sorption medium. It can be seen that the highest selectivity (2.65) possesses by APTsorb II*Na peat product.
  • Figure 8 represents a graphical representation of selectivity coefficient to sorb cadmium cations in the presence of Linc cations from aqueous solution containing both cadmium and zinc cations using ametal-loaded, thermally-activated, and acid treated peat.
  • Figure 9 represents a graphical representation of selectivity coefficient to sorb cadmium cations in the presence of zinc cations from aqueous solution containing both cadmium and zinc cations using ametal-loaded, the thermally activated and chemically treated by means of an acid solution followed by a salt solution peat sorption medium (APTsorb III*M). From Figures 9-I 1 it can be seen that the highest selectivity (2.65) possesses by APTsorb II*Na peat product.
  • Figure 10 represents a graphical representation of the selectivity of different peat media to adsorb cadmium cations in the presence of zinc cations and activity to adsorb cadmium cation from aqueous solution.
  • Figure 11 represents a graphical representation of breakthrough capacity to adsorb cadmium cations in the presence of zinc cations from aqueous solution containing both cadmium (concentration 5 ppm) and zinc (concentration 30 ppm) cations using different media and under 2 different flow velocities.
  • Figure 12 represents a graphical depiction of the cadmium adsorption from an aqueous solution stream containing only cadmium and zinc cations at two different flow rates using asodium-loaded sorption medium of the present invention (APTsorb II*Na).
  • the cations placed on the active sites of the partially decomposed organic material in the sorption medium will alter the coefficient that defines the equilibrium and increase the adsorption capacity more in favor of adsorption of major toxic metals found in the waste water at the expense of less toxic metals found in higher concentrations in the waste water. This allows the end user to target the major toxic metals for adsorption by the sorption medium containing the cations contributed by the preselected solution of soluble salts.
  • the sorption medium of this invention can be used in a variety of aqueous solution treatment processes, such as wastewater treahent for removing heavy metal constituents via ion-exchange and complexation mechanisms, and also reducing the levels of manganese, iron, and other naturally-occurring metals found in the peat substrate from leaching back into the waste water.
  • ⁇ ⁇ partially decomposed organic material means natural occurring, carbon-based, organic materials that have partially decayed or decomposed over time in the ground, or are plant or animal-based products that are subjected to a bacterial or thermal decomposition process to partially decompose the organic materials therein.
  • Such partially decomposed organic material cover a variety of substances including without limitation compost media (e.g., leaf compost media, peat, plant by-products and combinations thereof ,livestock manure, sewage sludge, lignite coal, partially decomposed wood, and combinations thereof. It also includes inorganic substances like apatite (calcium phosphate) and zeolites. Such partially decomposed organic material must also exhibit an ion-exchange capacity between 5-200 mEq per 100 g of organic material, as measured by Barium Acetate Procedure. Compost media is any decayed organic matter. Plant by-products may include partially decomposed plants, leaves, stalks, and silage, for example. Livestock manure is the dung and urine of animals.
  • compost media e.g., leaf compost media, peat, plant by-products and combinations thereof ,livestock manure, sewage sludge, lignite coal, partially decomposed wood, and combinations thereof. It also includes inorganic substances like apatite (calc
  • Sewage sludge is solid, semi-solid, or liquid residue generated by the processes of purification of municipal sewage.
  • aqueous solutions means any water-based solution containing an environmental impurity as a solute produced by manufacturing, agricultural, or mining industries or population communities. Examples include, without limitation, wastewater discharges; industrial streams; storm water runoffs; mine dewatering streams from mining pits; animal slaughterhouse, cattle-yard, and other agricultural runoffs; spent processing waters emanating from mining, grinding, milling, metallurgical, or extraction process; and hydrofracking.
  • impurities means any chemical element or compound found in an aqueous solution that poses a health risk to humans or animals, or is otherwise subject to environmental laws or regulations, including; without limitation heavy metals like arsenic, lead, mercury, cadmium, manganese, iron, zinc, nickel, copper, molybdenum, cobalt, chromium, palladium, stannum, or aluminum; radioactive materials like cesium or various isotopes of uranium; sulfates, phosphorous, selenium, boron, ammonia, refrigerants, and radon gases.
  • particles includes any three-dimensionally hardened shaped product formed from the partially decomposed organic material, including, without limitation, granules or pellets.
  • inEq means milliequivalents.
  • the equivalent is a common unit of measurement used in chemistry and the biological sciences. It is a measure of a substance's ability to combine with other substances. The equivalent entity
  • mEq milliequivalents
  • empty becl contact time means the time required for a liquid in a carbon adsorption bed to pass through a carbon column, assuming all liquid passes through at the same velocity. It is equal to the volume of the empty bed divided by the flow rate.
  • sorption means a variety of chemical mechanisms for removing a chemical element or chemical compound from an aqueous solution, including cation- exchange, complexation, chelation, adsorption, or absorption.
  • about means approximately or nearly, and in the context of a numerical value or range set forth herein means ⁇ 2% of the numerical value or range recited or claimed.
  • ⁇ g means microgram or one-millionth of a gram or one one-one thousandth of a milligram.
  • ng means nanograms or 1 x 10 9 grams or 0.000000001 grams.
  • more-toxic metals means any chemical element or compound found in an aqueous solution that poses a health risk to humans or animals, or is otherwise subject to environmental laws or regulations, including without limitation heavy metals like arsenic, lead, mercury, cadmium, manganese, iron, nickel, copper, molybdenum, cobalt, chromium, palladium, stannum, or aluminum; radioactive materials like cesium or various isotopes of uranium; selenium and boron.
  • heavy metals like arsenic, lead, mercury, cadmium, manganese, iron, nickel, copper, molybdenum, cobalt, chromium, palladium, stannum, or aluminum
  • radioactive materials like cesium or various isotopes of uranium; selenium and boron.
  • less-toxic metals means any chemical element or compound found in an aqueous solution that does not necessarily pose a health risk to humans or animals or is otherwise subject to environmental laws or regulations, including without limitation metals like magnesium, b ⁇ ;ryllium, strontium, barium, calcium, manganese, copper, zinc, iron, potassium, lithium, as well as ammonium and ammonium groups.
  • metals like magnesium, b ⁇ ;ryllium, strontium, barium, calcium, manganese, copper, zinc, iron, potassium, lithium, as well as ammonium and ammonium groups.
  • peat the partially decomposed organic matter starting material
  • the invention is not limited to peat-based sorption material.
  • the end-use applications for the sorption media of the present invention extend well beyond the treatment of heavy metals in wastewater streams described in this Application. They can also serve as solid-phase extraction tools, as well as a chemical useful in the mining industry for concentrating copper.
  • peat is used as the starting partially decomposed organic material 12.
  • peat inay be used for puzposes of this invention, including without limitation, reed sedge, sphagnum peat, high moor peat, transitional moor, and low moor peat.
  • the peat material should be dug from the ground and used in its natural state without any further decomposition process steps. It may, however, be cleaned to remove sticks, stones, and other foreign debris from the fibrous peat material.
  • finely ground particles oI' an alkaline earth metal carbonate may be admixed into the peat material 12.
  • CaCO3 calcium carbonate
  • Such calcium carbonate should preferably have a particle size of about minus 325 mesh. It should be admixed on a weight ratio basis of about 1-5%, preferably 2%, with the peat material 12.
  • the substantially neutralized peat material 14 is then introduced to a granulating machine 16, such as one sourced from Andritz, Inc. of Bellingham, Washington.
  • the loose, substantially neutralized fibrous peat material 14 will be tossed around inside the drum of the granulator to cause the fibers to adhere to each other, and build up granules of desired size.
  • a binder additive like lignosulfonate may be optionally added to the peat material in the granulator drum to assist this granulation process.
  • the loose, substantially neutralized peat material 14 may be introduced to an extruder. This extruder will apply pressure to the fibrous material to produce pellets of desired size. Such an extruder may he sourced from J.C. Steele & Sons of Statesville, North Carolina.
  • the peat granules or pellets 16 are sent to a dryer 18 such as a belt or rotary dryer sourced from Harris Group of Atlanta, Georgia.
  • the peat granules or pellets will travel through the length of the dryer having an inlet temperature of about 400 °C and an outlet temperature of about 80 °C, so that the natural 40% wt moisture level of the peat material contained in the peat granulEs or pellets will be reduced to about 10-14% wt moisture.
  • this drying step 18 should be carried out across a temperature range of about 80-400 °C with the preferred temperature of exposure being about 90 °C for about 45 minutes.
  • the resulting dried peat granules or pellets are then crushed and screened to an appropriate size of about 6 mesh x 30 mesh to 30 x 100 mesh.
  • the dried peat granules or pellets 18 are then introduced to a ther-rraal activation step 20, also known as "torrcfaction.”
  • the peat granule or pellet is put in a jacketed ribbon mixer that has thermal fluid like oil circulating through the jacket.
  • the ribbons are fitted with “lifters,” which pick up the granular peat and drop it through the atmosphere inside the ribbon mixer. This exposure to the hot, inert atmosphere is critical to bringing the granule up to temperature as quickly as possible. During this heating process, a unique combination of time and temperature are critical for the production of the thermally-activated peat granule (called “APTsorb II" within this Application).
  • Activation can be defined as input oi' external energy into a chemical system to bring about activation of the system. This activation will initiate or expedite thermochemical reactions.
  • heat as a form of energy is first provided by the thermal ⁇ Iluid circulating in the ribbon mixer. This heating process results in the chemical reaction- decomposition of hemiceilulose, which occurs naturally in partially decomposed plant matter such as peat. The decomposition of hemicellulose is itself exothermic, as evidenced by a continuing rise in atmospheric temperature even when the heat input of the thermal fluid is stopped.
  • lactones As it decomposes and gives off heat, hemicellulose is converted to highly reactive, cyclic molecules called lactones. Some of these lactones escape the reaction zone along with moisture, but given the correct starting temperature and duration, the bulk of the lactones remain within the reaction zone and undergo a cross-linking polymerization with the natural matrix of the peat. This cross-linking reaction is the result of the exothermic reaction of thermal decomposition of
  • the temperature of the thermal fluid is quickly raised to approximately 300- 320 °C, more preferably 304 °C, to therfnally czctivc ⁇ te the peat granules to increase their hardness.
  • the temperature inside the mixer slowly rises as volatiles and contained moisture are driven off. This gasified water and volatile mix constitute the "inert" atmosphere, and work to purge air out of the ribbon mixer. As the temperature in the atmosphere inside the mixer climbs into the 216 °C range, the rapid breakdown of hemicellulose begins. This is the same reaction as torrefaction of wood.
  • This breakdown of hemicellulose is an exothermic chemical reaction which allows for a rapid rise in the temperature of the atmosphere inside the mixer.
  • the actual temperature of the granule is hard to determine but probably is much lower.
  • the above reaction is allowed to continue as the temperature is driven into the 271-277 °C temperature range. At this point, the boiler that is used to heat the thermal fluid is turned o f. The above reaction releases enough heat to maintain the temperature of the atmosphere in the above range. The process is allowed to continue until approximately 20 minutes have passed where the temperature has been maintained above 271 °C.
  • the media is described as "partially activated.” This refers to the thermal energy that is delivered to the peat material to initiate the decomposition of hemicellulose in the tightly controlled manner that leads to the increase of structural hardness of the material without losing the natural ability of material to sorb metal ions. If the reaction were allowed to continue past the prescribed time, the resulting material would continue to gain structural hardness but would lose its ability for sorption of metal ions.
  • This thermal activation process step 20 should preferably be conducted at a temperature inside the activator of about 175-287 °C, preferably 200-275°C, more preferably 250 °C, and a time period of about 25-90 minutes, preferably 30-60 minutes, for achieving maximum granule hardness.
  • the activation step should be conducted for 25-90 minutes, preferably 25-40 minutes. It has been found that 32 minutes represents an optimal compromise as an activation step time duration For achieving desirable levels of both granule hardness and cation exchange capacity. Note that this activation temperature range is different from the higher 300-320 °C oil temperature used to heat the activator.
  • the thermal heat is applied directly to the dried peat granules 18 without any steam, carbon dioxide, nitrogen, or other inert gas media typically used within the industry in a physical c ⁇ ctivcztion process.
  • a thermal carrier like steam, carbon dioxide, nitrogen, or other inert gas media can be used in the thermal activation step 20 to deliver the heat as a form of energy to the peat granule.
  • the gas should preferably be carbon dioxide, and the peat granule should be exposed to it for a time period of about 20-90 minutes, preferably 40-60 minutes. Unlike the physical activation process known in the prior art, this inert gas is not used to oxidize the surface of the peat granule.
  • the heating process is stopped at this point, and water is injected in order to rapidly cool the product and stop the reaction.
  • Target moisture for the finished product should be at least 10% so as to prevent the thermally activated peat granules from becoming too hydrophobic. Danger of fire developing within the bagged product is greater if the finished product has less than 5%moisture content.
  • This thermal activation step results in a hardened media that maintains its structural integrity even when wet, and retains its affinity for metals.
  • the physical appearance of the APTsorb II peat granule is not substantially dit'ferent from its starting non-thermally-activated material (called "bioAPT")
  • bioAPT non-thermally-activated material
  • the degree of granule hardness for the resulting thermally-activated peat granule 22 of the present invention should have aBull-Pczn Hca ⁇ di ⁇ ess nzrmber of about 75-100%. More preferably, this Ball-Pan Hardness number should be about 80-98%.
  • a person skilled in the art will be able to determine the necessary hardness value falling within this range.
  • the peat granules thermally activated in the manner described in this Application will exhibit a copper cation-exchange capacity ("Copper CEC") of about 120 mEq/1008 of Cue ⁇ at a thermal activation temperature oi' about 232 °C, while a 287 °C temperature condition produces a partially activated peat granule with acation-exchange capacity of about 92 mEq/ 1 OOg of Cup ⁇ .
  • Untreated peat has a natural copper cation-exchange capacity of about 120 mEq/1008 of Cue+.
  • this tlieYrraal c ⁇ ctivc ⁇ tion step comprises torrefaction of the peat granule, which necessarily requires lower temperatures like the preferred 200-275 °C range identified above.
  • activation can be defined as the input of external energy into a chemical system to bring about activation of the system.
  • reaction is amedium-temperature, thermochemical process, commonly carried out around 250-300 °C, which significantly improves the grindability of wood and straw.
  • Peat naturally has carbohydrates in it, which undergo a thermochemical decomposition to produce lactones, which are then broken down into hydroxy acids that react with natural pol ⁇ nners found within the peat material to cf-oss- link, and as a result to harden the peat granule.
  • this relatively low- temperature range for the thermal activation step will preserve enough of the natural ion exchange capacity of the peat material to preserve the efficacy of the resulting ion exchange medium.
  • This combination of increased peat grana ⁇ le hardness and preserved ion exchange c ⁇ pc ⁇ city renders the peat product of the present invention an ideal, natural ion exchange medium for removing heavy metal cations from waste water.
  • Thermal activation is normally applied in the industry to activated carbon material to increase its sasrface c ⁇ rec ⁇ . Note that this 200-275 °C thermal activation temperature range of the present invention is considerably lower than the temperatures normally associated with conventional physical activation and chemical activation.
  • the starting material for, e.g., activated carbon will first be carbonized by pyrolyzing it at a high temperature generally within the range of 600-900 °C in an inert, oxygen-depleted atmosphere using gases like argon or nitrogen, followed by an activation step in which the carbonized material is exposed to an oxidizing atmosphere provided by, e.g., carbon dioxide, oxygen, or steam at a high temperature usually within the range of 600-1200 °C.
  • This carbonization step produces a large number of micropores within the surface of the carbonaceous starting material.
  • the physical activation step is used to drive off chemical compounds which might clog these pores.
  • the material can be then carbonized at a lower temperature (e.g., 450— 900 °C), which is still significantly high compared against the 200-275 °C partial activation temperature range of this invention.
  • This heat treatment will destroy the cation-exchange sites of the material.
  • the carbonaceous material will be treated with, e.g., sulfuric acid to increase its cation-exchayage sites by adding 503- groups to the surface structure to improve the cation-exchange capacity.
  • the process of the present invention seeks to partially activate the peat granules to an incomplete degree using relatively low temperatures for a relatively limited time period, without addition of chemical groups via chemical modification in order to increase granule hardness while maintaining or at least minimizing the decrease in cation-exchange capacity of the heat-activated peat material.
  • the APTsorb II thermally-activated peat granule 22 provides in combination a desired degree of granule hardness that prevents the medium from becoming damaged during a wastewater treatment process, along the a sorption activity level that is sufficient to remove a good portion of the toxic metal ions from the wastewater.
  • This relatively low-cost peat granule medium is the subject of U.S. Patent Nos. 8,232,225 and 8,685,884, both granted to American Peat Technology, LLC. Chemical T ⁇ eatm.ent Process fot ⁇ the APT,sorb III Sorption Meclitiim.
  • a challenge faced by the wastewater treatment industry is the fact that some toxic metals like cadmium often are present in wastewaters at relatively Lower concentrations on the order of 10 ppb. But due to their serious toxicity level, government regulatory standards require even lower concentrations of cadmium which creates the need for a peat granule product exhibiting an even greater sorption activity for cadmium and other seriously toxic metals, while minimizing leaching of other metals from the parent material.
  • Achemically-treated, thermally-activated sorption medium called "APTsorb III" previously developed by the same co-inventors of this Application and the subject of separate patent application U.S.SN.13/841,526 filed on March 15, 2013 fills this need.
  • This chemical treatment process 30 occurs after- the thermal activation step 20, as shown in Fig.2.
  • the peat granules are immersed in an cicid solution like a 1 molar (lesser or greater) solution of hydrochloric acid, formic acid, acetic acid, sulfuric acid, nitric acid, or phosphoric acid.
  • the resulting chemical reactions for this acid solution treatment step 32 can be carried out at room temperature, but proceed much faster (and more cost effectively) at elevated temperatures.
  • Favorable results are obtained at temperatures as high as 100 °C (210 °F). At the upper end of this temperature range, reaction time can be shortened from 24 hours to 10 minutes.
  • the acid solution will dissolve the mineral forms of calcium, manganese, iron, and possibly other metals.
  • This acid solution treatment step seeks to remediate one of the intrinsic flaws of natural peat.
  • Peat material has been formed by nature in ametal-enhanced environment.
  • the ground and surface waters that feed wetland systems are generally rich in minerals and metals.
  • the waters of northern Minnesota because of the geology of the region, have raised concentrations of manganese.
  • Manganese is a benign metal abundant in the glacial till that was uniformly deposited across the upper Midwest during the last glacial events.
  • Manganese has a complicated chemistry and readily morphs between dissolved and mineral forms depending on the chemical matrix of the water.
  • peat forms manganese is accumulated in two ways. First, the dissolved form of the metal is adsorbed onto the active sites of the organic surface and held there by chemical bonds.
  • dissolved manganese precipitates inside the peat matrix and results in the accretion of interstitial minerals. Both types of accumulation result in increased manganese concentrations of the natural peat.
  • the acid-treated peat granules are yinsed with water in either a batch process oi- continuous process to remove metal ions from pore spaces and surfaces of the peat granule until the test for' the presence of calcium ions is negative.
  • This rinse step 34 can he conducted at room temperature, but is more cost-effectively done at temperatures as high as 93 °C (200 °F). The manganese, calcium, and other cations, as well as residual acid are removed from the peat granule surface.
  • This rinsing step is repeated one snore time, preferably six more times, or until the test for presence of calcium and/or chloride ion is negative.
  • metal ions comprising mostly calcium, manganese and iron ions
  • this rinse step 34 metal ions (comprising mostly calcium, manganese and iron ions) need to be removedfrom the complexation and ion exchange sites (where they ai•e weakly held) on the internal and external surfaces of the peat granule. This is accomplished by immersing the peat granule in a 1 molar (lesser or greater) solution of sodium chloride or other salt solaatiof7 of Na+, Li+, K+, or Cs+.
  • this salt solution treatment step 36 can be carried out at room temperature, but proceed much faster (and more cost-effectively) at temperatures as high as 100 °C (210 °F). At the upper end of this temperature range, reaction time can be shortened from 24 hours to 90 minutes.
  • the salt solution will displace the metal ions from the complexation and ion exchange sites in much the same way as sodium or magnesium ions are used to displace metal ions in the regeneration of standard ion exchange resins.
  • the peat granules are rinsed in water to remove the residual salt solution and any remaining metal ions from the internal and external surfaces of the peat granule. This rinse step 38 should be continued until the concentration of chloride ions is down to an acceptable level.
  • the finished peat granule APTsorb III sorbent medium 40 following the chemical treatment process 30 will exhibit approximately the same granule hardness as for the thermally-activated granule produced by process 20. Thus, this chemical treatment process does not diminish the important peat granule harness properties achieved through thermal activation.
  • the final thermally-activated, chemically-treated peat APTsorb III product will typically have a granular size distribution as shown below in Table I with about 95% of the granules falling within the 16-50 mesh size range. Table 1
  • the capacity and activity for the finished thermally-activated, chemically-treated APTsorb III product 40 is measured through a 24-hour equilibrium with a 30,000 ppb cadmium solution in a 1:100 (w/v) ratio. Following the equilibrium and filtering, the peat granule filtrate is analyzed for cadmium concentration, as a measure of adsorption activity generally, using cadmium as a proxy. A higher concentration result translates into a granule with less CEC and activity.
  • Granules chemically treated in the manner described for the APTsorb III product under this invention will typically have equilibrium filtrates between 50 and 200 ppb cadmium, while increasing the active sites on the peat granule surface and capacity of those granules For heavy metal cation affinity, while also minimizing the biological oxygen demand in the treated waste water.
  • the acid solution treatment step 32 and salt solution treatment step 36 displace Ca+2 and Mn+2 ions that are occupying complexation and ion exchange sites on the internal and external surfaces of the peat granules.
  • APTsorb III granules prepared as described herein will leach less than 5 ppb manganese, preferably less than 1 ppb manganese, into water when acting as an ion- exchange medium in a column contactor.
  • Manganese is a contaminant whose presence should be controlled in potable water.
  • Still another characteristic of the thermally- activated, chemically-treated APTsorb III peat granule product is its maximum measured loading capacity for cadmium ions.
  • This value is 35-50 mEq/l OOg at almost unlimited Cd +2 concentration dosing, preferably 40-45 mEq/l OOg.
  • the APTsorb III sorbent medium 40 retains much of its inherent cation-exchange capacity, obtains an increased capacity for metals in solution, and has increased strength and durability when exposed to water, and less leaching of organic molecules. These characteristics make the media well-suited for waste water remediation, and other treatments of aqueous and nonaqueous solutions to remove contaminants and impurities present in wastewaters at lower concentration levels.
  • the APTsorb III*M granules produced a breakthrough capacity of 16.49 mg/g Cd when used to treat a cadmium cations-only aqueous solution (Example 5). But this breakthrough capacity value plummeted to 0.47 mg/g Cd when the APTsorb III*M granules were used to treat a cadmium and zinc cations competing metals aqueous solution environment (Example 6).
  • the present invention of this Application produces a thermally-activated, chemically-treated metal form of the APTsorb II peat granules ("APTsorb II*M") that provides a beneficial combination of granule hardness, selectivity for a first type of metal cations (e.g., cadmium) over a second type of metal cations (e.g., zinc), a high activity for adsorption of the first type of metal cations, and a high level of breakthrough capacity for loading the first type of metal cations onto the active surface sites of the peat granule.
  • APTsorb II*M thermally-activated, chemically-treated metal form of the APTsorb II peat granules
  • the metal cations M + located on the peat granule active sites which are described above as being Na + resulting from the sodium chloride salt solution used to chemically treat the sorption medium, will be displaced by the cadmium (Cd 2+ ) cations found in the aqueous solution during the ion exchange treatment process with the result that the cadmium cations are absorbed by the peat granules with the benign Na + cations dispersed in the treated aqueous solution.
  • the thermally-activated peat granules 22 having a desired degree of hardness and cation exchange capacity characteristics are treated to a chemical treatment process 50 after the thermal activation step.
  • First the peat granules are immersed in a sodium chloride or other salt solution of a metal cation Me.
  • These chemical reactions for this salt solution treatment step 52 can be carried out at room temperature, but it will proceed much faster (and more cost effectively) at temperatures as high as 100 °C (2 10 °F). At the upper end of this temperature range, reaction times can be shortened from 24 hours to 90 minutes.
  • the salt solution will displace metal ions comprising mostly calcium, manganese, and iron from the complexation and ion exchange sites on the peat granules in much the same way as sodium or magnesium ions are used to displace metal ions in the regeneration of standard ion exchange resins.
  • the peat granules are rinsed in water to remove the residual salt solution and remaining metal ions from the internal and external surfaces of the peat granule.
  • This rinse step 54 should be continued until the concentration of the anion constituent of the salt is down to an acceptable level. Again, this can be done at room temperature, but it proceeds at a much faster rate at a temperature of 100 °C (210 °F).
  • the rinsed peat granules bearing the M + cations contributed by the salt solution are dried for about 24 hours. This drying step 56 is carried out at a temperature around 105 °C.
  • the finished APTsorb II*M peat granules 58 following the chemical treatment process 50 will exhibit approximately the same granule hardness as for the thermally- activated APTsorb II granules 20. Thus, this chemical treatment process does not diminish the important peat granule hardness properties achieved through thermal activation. But at the same time, the resulting APTsorb II*M peat granules 58 exhibit a number of other beneficial properties for use of the APTsorb II*M peat granules in a wastewater treatment process where competing toxic metal cations are present in the wastewater.
  • the granules exhibit a selectivity a of a first type of more-toxic metal cations (such as cadmium, lead, copper, or other metals at high concentrations) over a second type of less- toxic metal cations of (such as zinc, aluminum, or iron); greater adsorption activity for the first type of more-toxic metal cations; and greater breakthrough capacity for the first type of more-toxic metal cations.
  • a first type of more-toxic metal cations such as cadmium, lead, copper, or other metals at high concentrations
  • a second type of less- toxic metal cations of such as zinc, aluminum, or iron
  • this special preselected solution of soluble salts used in step 52 comprises any compound having a cation constituent and an anion constituent where: • the cation constituent is selected from the group consisting of any l+ or 2- ⁇ cation of, e.g., ammonium (NHa- ⁇ ), ammonium groups (NR4+), sodium, potassium, lithium, cesium, beryllium, magnesium, calcium, barium, manganese, copper, zinc, strontium, or iron; and
  • HSO4- 5032-, NO3-, NOZ -, PO43 , HP042-, HZP04-, Cl-, I-, Br -, F-, HCOO-, CH3C00-, CZHSCOO-, C3H ⁇ C00-, C4H ⁇ C00 ⁇ , C104", HCO3-, or C032_.
  • Sodium represents the preferred cation constituent form for the preselected soluble salt solution with chloride (NaCI) being used.
  • W hile the calcium carbonate or other alkaline earth metal carbonate compound described above represents a preferred embodiment of this invention, because of the belief that it synergistically interacts with the M+ cations and peat material in the
  • a PTsorb II*M granules to increase the selectivity, sorption activity, and breakthrough capacity characteristics for the more-toxic metal cations contained in the wastewaters treated with the APTsarb II*M product
  • other compounds may be used in lieu of the calcium carbonate or other alkaline earth metal carbonates to achieve these objectives.
  • limestone or Ca(OH)Z may be added to the peat during production of the APTsorb II granules used to produce the APTsorb II*M product.
  • a non- water soluble salt of polyprotic acids preferentially weak polyprotic acids
  • Such anon-water soluble salt should be made out anzons of polyprotic acids such as PO43 , HP042-, HZP04-, 5042-, HSO4-, C204Z- (oxalic acid), HC204-, C ⁇ H ⁇ 042- (adipic acid), C ⁇ H904- (adipic acid), C ⁇ H4(COO)z ⁇ - (phthalic acid), or C ⁇ HaCz04H-; and cations of an alkaline earth metal cations such as Cat+, Mg2 ⁇ , Be2 ⁇ , Ba2+, or SrZ-F.
  • polyprotic acids such as PO43 , HP042-, HZP04-, 5042-, HSO4-, C204Z- (oxalic acid), HC204-, C ⁇ H ⁇ 042- (adipic acid), C ⁇ H904- (adipic acid), C ⁇ H4(COO)z ⁇ - (phthalic acid), or C ⁇ HaCz04H-
  • the APTsorb II peat granule media was prepared using peat of a reed-sedge type commercially available from American Peat Technology, LLC of Aitkin, Minnesota.
  • the raw peat material was first dried to a moisture content of about 40% wt.
  • Calcium carbonate (2% by weight) was added to raw peat and the mixture was extruded into pellets, dried again to reduce the moisture content to about 12% wt, and finally crumbled and sieved. This process resulted in a multifunctional granular media called "bioAPT.”
  • bioAPT multifunctional granular media
  • the finished bioAPT peat granule with a size range of 10 x 30 mesh was then thermally activated to produce the APTsorb II media.
  • the bioAPT granules were introduced into a jacketed ribbon mixer.
  • the mixer had thermal fluid circulating through the jacket at a temperature of about 300 °C, thereby effectively heating the atmosphere inside the mixer.
  • the mixer ribbons were fitted with "lifters” that picked up the media and dropped it through the heated atmosphere.
  • the design of the mixer and the resulting chemical reactions resulted in an oxygen-free atmosphere inside the mixer.
  • the bioAPT material was heated and mixed within this oxygen-free atmosphere for approximately 32 minutes, at which point the chemical reactions necessary for thermal activation were complete, and the granular media was converted into the APT sorb II media. This media was then quickly cooled, using a water spray, and the moisture content was adjusted to about 10% wt moisture level.
  • Four production trials of the APTsorb II peat granules were recorded and tested for quality control purposes. Observations with respect to activation temperatures, product yield, copper cation exchange capacity, and ball-pan hardness were made as shown in Table 2.
  • a modified ASTM D3802-10 standard test method was used for purposes of measuring Sall-Pan Hardness of the thermally-activated APTsorb II peat granules.
  • the moisture content of the media was measured using a Mettler Toledo MJ33 moisture meter. Water was then added to 200 g media in order to bring the moisture content to 35 wt. The media was mixed thoroughly and kept for• 15 min at room temperature. At the end of the equilibrium period, the media was free-flowing and not sticky, indicating that the correct moisture content had been reached.
  • One hundred thirty grams of the moistened media was screened on a 50 mesh sieve shaker for 3 minutes.
  • a 100 g sub- sample (A in the formula) of media after screening (usual particle size is 10-50 mesh) was placed in the sieve catch pan, and 36 steel balls (15.9 mm diameter, 16.3 g each) were added.
  • the catch pan was covered, and the sub-sample was shaken for 6 minutes to approximate abrasion and attrition. Following this abrasion step, the steel balls were removed, and the media was screened again on a 50 mesh sieve for 5 minutes. The amount of media retained on the 50 mesh screen was recorded in grams (B in the formula).
  • CEC cation-exchange capacity
  • the exchange of cations on the surface of the media is measured using the media as produced, without first converting the surface to an H ⁇ form, and the indication of exchange is measured by the concentration of the exchanging ion before and after contact with the media.
  • the exchanging ion in this case is copper, prepared as a 1000 ppm solution of copper using copper chloride, buffered to a pH of about 4.8.
  • the buffer solution was prepared by adding 1.68 ml of glacial acetic acid and 9.51 g of sodium acetate trihydrate to Type I deionized water and diluting to 1 L.
  • the buffer solution was then used to make the 1000 ppm copper solution by dissolving 2.683 ⁇ of CuClz*2Hz0 in the 1 L of buffer solution.
  • the media was dried on a Mettler Toledo MJ33 moisture meter at 160 degrees °C until its weight was stable For 30 seconds.
  • One gram of the dried media was then added to 100 inl of the 1000 ppm copper solution, and the mixture was stirred at around 300 RPM for 3 hrs at room temperature.
  • the flask and stirring rod were positioned so that the rod made contact against the wall of the flask, thereby effectively pulverizing the media over the course of the stirring period.
  • the mixture was filtered and the concentration of CuZ+ was measured by colorimetry or by graphite furnace atomic absorption
  • a 2 L volume of a 1N solution of HCI was added to 1 kg of the APTsorb II media at room temperature.
  • the mixture was kept at room temperature for 24 hrs with periodic shaking in such a fashion so as not to destroy the granules.
  • the pH was maintained at a value of 2 or lower.
  • This acid treatment was completed when the concentration oI' calcium, manganese and other bivalent ions reached maximum concentrations in the solution as determined by the titration procedure described below.
  • the mixture was filtered and washed six times with water or until the test for the presence of chloride ions in the filtrate, as described below, was negative.
  • the volume of combined acid and rinsing solutions was 11 L.
  • the removal of the organics and chloride ions by the aqueous solution at 180 °C accounts for the reduction of mass for the APTsorb III peat granules.
  • the tests ref erred to above are critical for the production of the APTsorb III peat granules. If the bivalent ion concentration in the acid solution does not reach maximum while the solution pH remains below 2, it indicates that the mineral fraction that naturally occurs in the parent peat material is incompletely removed. The incomplete removal of this mineral fi-action results in the leaching of manganese and calcium later when the product is utilized as a filtration media. Also, the acid treatment results in the exchange of metals for hydrogen ions on the active surfaces of the peat material, thereby "cleaning" the impurities inherent in the parent peat material.
  • An ammonium buffer was prepared by adding 20 g of ammonium chloride and 74 ml of ammonium hydroxide (28-30% NH3) to a flask and diluting it to 1 liter with Type 1 deionized water.
  • the pH of the buffer was 10.02.
  • Ten milliliters of the HCl acid treatment filtrate was added to an Erlenmeyer flask and diluted with 50 tnl of Type I deionized water.
  • the following test was used to detect the presence of chloride ions in the rinsing water: Five tenths milliliter of a 1 %solution of silver nitrate was added to a 20 ml sample of rinsing water. If chlorides were present, a white precipitate in the form of silver chloride formed immediately, which evidenced the need for additional rinsing. The following cadmium equilibrium quality control test ("QC test") method was used to measure the adsorption activity of peat granules. One gram of dried media was added to 100 ml of a 30 ppm solution of Cd 2+ in Type I deionized water.
  • QC test cadmium equilibrium quality control test
  • the equilibrium was rolled at 8 rpm at room temperature (20 ⁇ 2°C) in a leak-proof vessel for 24 h.
  • the mixture was filtered using 0.45 ⁇ polypropylene syringe filter membrane.
  • the liquid fraction was preserved by adding concentrated HN0 3 and analyzed by GFAA
  • the APTsorb III peat granules for this experiment were produced by mixing 500 g of APTsorb II material and 1 L of 1 N HCl. The mixture was kept at room temperature for 24 h with periodic shaking, so as to not destroy the granules. After the acid treatment, the media was rinsed with deionized water until the filtrate was free of chlorides as described in the test above. The media was then mixed with 5 L of 1 M NaCl solution and heated. The mixture was held at 90- 100 °C for 90 minutes, filtered while still hot, and rinsed until free of chlorides as described above. The treated media was then dried for 24 h at 105 °C.
  • the adsorption activity of the APTsorb III material was measured by the cadmium equilibrium QC test. Filtrates were preserved and analyzed for manganese and cadmium, using graphite furnace atomic absorption spectrometry. The results are shown in Table 4 below. Table 4. Concentration of Mn and Cd after QC test with initial concentration of Cd equal 30,000 ppb.
  • the acid and salt treatments together essentially greatly reduced the presence of manganese in the peat granule to free up active sorption sites, while also serving to eliminate the leaching of manganese into the aqueous solution, which can be undesirable for some wastewater treatment end uses.
  • the cadmium adsorption of the acid/salt-treated media indicates much higher sorption activity, particularly for cadmium, compared with the parent peat material and the APTsorb II material.
  • the first step an acid treatment step, effectively removed the greater part of the mineral form of manganese and other contaminants, and likely also displaced some of the ions that are filling ion-exchange sites with hydrogen.
  • the second step a salt treatment step, regenerated the other active sites besides ion-exchange on the media to a sodium fonn.
  • Sodium which is a single-valent cation, is not the preferred ion for those sites, but the equilibrium of the process is driven by concentration and heat to the sodium-form state. Therefore, when the media is subjected to a target metal, competing ions with a valence of +2 readily displace the sodium ions, which makes the media more active towards sorption of metals compared with the parent material.
  • the typical test procedure uses 1 g of APTsorb II or APTsorb III peat granules dried at 105 °C for 24 hrs, which was added to 100 ml of a solution of metal ion in Type I deionized water. The mixture was tumbled in an end- over-end fashion at 8-28 rpm at room temperature (20 ⁇ 2°C) in a leak-proof vessel for 24 hrs. The mixture was filtered using 0.45 ⁇ polypropylene filter membrane, and the filtrate was preserved by adding of a solution of HNO 3 . The initial and final
  • the experimental set-up for the column system consisted of a plastic column resulting in a bed size of 62 mm in diameter and 50 mm deep and a bed volume of 150.95 cm 3 . 72.3 g of APTsorb III sorption medium prepared in accordance with Example 3 and then loaded with sodium cations on its active sites, and having a particle size distribution of between 10-50 mesh, were submerged in type I deionized water ( 18.2 MOhm) for 10 hours to wet the surface of the granules and allow the granules to swell. Plastic mesh was installed at both the top and the bottom of the column.
  • the column was packed with 20 mm of HCl-washed Red Flint filter gravel (granular size 3-5 mm) sourced from Red Flint Rock and Stone of Eau Claire, Wisconsin, and then with 50 mm of the pre-wetted APTsorb III granules.
  • a synthetic solution of cadmium with a concentration 6 ppm was prepared by dissolving cadmium chloride in Type I deionized water ( 18.2 MOhm).
  • the amount of metal ion adsorbed in the column was determined from the area above the breakthrough curve assuming the breakthrough happens when the concentration of the metal in the effluent reaches 50 ppb.
  • the absorption capacity of the chemically-treated APTsorb III granules was verified by digesting the spent granules and measuring the concentration of the metal ions. Employing a flow rate for the cadmium aqueous solution of 1.99 BV/hr and a contact time of 30.19 minutes, the breakthrough capacity for adsorption of cadmium at breakthrough concentration 50 ppb was found to he 16.43 mg/g at 0.1 m/hr flow velocity. "Breakthrough capacity" measures the effective total loading of the peat adsorption sites with cadmium when the column effluent concentration climbs to 50 ppb cadmium. The data for this experiment is shown in Table 6 and Fig.5 Table 6.
  • the aqueous solution contains a second metal cation like zinc (Zn 2+ ), which frequently occurs in waste waters, then the presence of the Zn 2+ cations will retard the adsorption capacity of the peat granule sorption medium for the Cd 2+ cations. Because the Zn 2+ cations usually appear in the wastewater solution at higher concentrations than the Cd 2+ cations, the Zn 2 + cations occupy many of the active sites on the peat granules to the exclusion of Cd 2+ adsorption.
  • Zn 2+ zinc
  • Example 5 Using the Column Procedure described above (Example 5), a synthetic solution of cadmium and zinc with concentrations 4.59 ppm cadmium and 29.3 ppm zinc was prepared by dissolving cadmium chloride and zinc sulfate in Type I deionized water ( 18.2 MOhm). APTsorb III peat granules were loaded into the column having a column diameter of 62 mm, a bed depth of 5 cm, and a bed volume of 15 1 cm ' .
  • APTsorb III peat granule medium As exemplified by Example 6 using the APTsorb III medium, for selective adsorption of cadmium cations over zinc cations within a competing metals aqueous solution environment, the research focus was changed to metal cation-loaded APTsorb II peat granules (APTsorb II*M). This was done despite the tact that the cadmium adsorption activity for the APTsorb II peat granules is much lower than the cadmium adsorption activity for the APTsorb III granules.
  • APTsorb II*M metal cation-loaded APTsorb II peat granules
  • APTsorb II*Na peat granule medium was prepared as follows: 500 g of APTsorb II granules prepared in accordance with the method set forth in Example 2 was added to 2.5 L of 1 M NaCI solution. The resulting mixture was refluxed by placing it on a hot plate and gently boiled for 90 minutes at a temperature around 100 °C. This mixture was then filtered while still hot using a Buchner funnel under vacuum to remove the solution. The filtrate media was then rinsed with 3 L of hot D.I. water. The resulting rinsed media was then rinsed with 4-6 L of room temperature D.I.
  • a set of acid and metal salt-treated derivatives of the APTsorb II*M medium described above were prepared as follows: 500 g of APTsorb II was added to 1 L of a 1 N solution of HCI in type I D.I. water. The mixture was kept at room temperature for 24 hours with periodic shaking so as not to destroy the granules. After the acid treatment, the media was rinsed with deionizcd water until the filtrate was free of chlorides as described in the test above. The media was then mixed with 2.5 L of 1 M NaCI solution and heated. The mixture was held at 90-100°C for 90 minutes, filtered while still hot, and rinsed until free of chlorides as described above. The treated media was then dried for 24 h at 105°C to give APTsorb II-HC1*Na peat granular media.
  • APTsorb III was described in Example 2.
  • APTsorb III*Na granules were prepared using the following procedure: 500 g of APTsorb III granules prepared in accordance with the method set forth in Example 2 was added to 2.5 L of t M NaCI solution. The resulting mixture was refluxed by placing it on a hot plate and gently boiled for 90 minutes at a temperature around 100 °C. This mixture was then filtered while still hot using a Buchner funnel under vacuum to remove the solution. The filtrate media was then rinsed with 3 L of hot D.I. water. The resulting rinsed media was then rinsed with 4-6 L of room temperature D.I.
  • the cadmium adsorption exhibited by the different media was measured using a Cadmium Equilibrium Test as follows: 1 g of dried media was added to 100 ml of a 30 ppm solution of CdZ+ in type I D.I. water. The mixture was rolled at 8 rpm at room temperature in a leak-proof vessel for 24 hours. The solution was filtered using 0.45 ⁇ m polypropylene syringe membrane filter. The filtered solution was preserved by concentrated HNO3 (TraceMetal Grade) and analyzed by flame spectroscopy or graphite Furnace atomic absorption spectroscopy for the concentration of Cd2+ ion. This procedure measures the activity of the media toward sorption of Cd2+ cations.
  • a lower concentration of Cd2 ⁇ in the solution translates into more of the Cd2+ being adsorbed onto the media and thereby indicates greater activity.
  • Cadmium adsorption data for the different derivatives of APTsorb II*M, APTsorb II-HCI*M, and APTsorb III*M samples are presented in Table 8 and Figure 10. These data represent the activity of the sample toward sorption of cadmium. The lower the remaining concentration of Cd2+ contained in the solution represents the higher activity of the peat granule sample. The most active samples are APTsorb III*M, where M is an alkaline metal. Adso ⁇ ptiofz Activity of Peat Granules by Zinc Equilibrium Test
  • the zinc adsorption exhibited by the different media was measured using a Zinc Equilibrium Test as follows: 1 g of dried media was added to 100 ml of a 30 ppm solution of Zn2+ in type I D.I. water. The mixture was rolled at 8 rpm at room
  • the selectivity for cadmium cations over zinc cations and the distribution coefficients for the various samples were measured as follows: 1 g of dried peat media was added to 100 ml oI' a 30 ppin solution of Zn2+ and 30 ppm solution of Cd2+ in type I D.I. water. The mixture was rolled at 8 rpm at room temperature in a leak-proof vessel for 24 hours. The mixture was filtered using 0.45 ⁇ m polypropylene syringe membrane filter. The solution was preserved by adding a concentrated HNO3 (TraceMetal Grade) and analyzed by flame spectroscopy or graphite furnace atomic absorption spectroscopy for the concentration of Zn2+ and CdZ- ⁇ ions.
  • HNO3 RaceMetal Grade
  • C,,,oi manuallyt;obook concentration of Zn2+ ions in a solution after equilibrium, mmol/L.
  • the distribution coefficient of Cd2+ cation was calculated using the following formula: CCd solution —concentration of CdZ+ ions, which was sorbed on the peat granules, mmol/g.
  • the APTsorb II medium without metal cation loading exhibits greater adsorption selectivity (1.62) for cadmium over zinc c ations within a competing metals cation aqueous solution environment, compared with t he APTsorb III medium (1.26). But, this selectivity value also remains essentially unchanged from the selectivity exhibited by the raw peat starting material (1.68).
  • a PTsorb II*M a metal cation-loaded derivative of APTsorb II medium
  • the selectivity results are improved, particularly for the alkaline metal ( +1) derivatives. This is particularly true for APTsorb II*Na medium having a selectivity value of 2.65, which represents an average of several experimental results.
  • a selectivity value of 3.00 was also obtained for the APTsorb II*M medium. See also APTsorb II*Li ( 1.90) and APTsorb II*K (1.97).
  • the selectivity values for the alkaline earth metal (+2) d erivatives also look beneficial. See APTsorb II*Ca (2.39), APTsorb II ⁇ Mg (1.73), A PTsorb II*Ba (2.41), APTsorb II*Mn (1.83), APTsorb II*Li (1.90), and APTsorb II* Fe(III) (1.99). Meanwhile, the selectivity values for these APTsorb II*M derivatives is greater than the APTsorb III*M derivatives.
  • APTsorb II-HCl*M derivatives The acid treatment applied to the APTsorb II-HCl*M derivatives seems to have harmed the selectivity property for those media. This may be due to the fact that the HCI acid reacted with the calcium carbonate contained in the APTsorb II starting material. Therefore, calcium carbonate along with metal plays a key role in increasing the selectivity.
  • the sorption activity for Cd2+ is decreasing with an increase of charge of the metal: APTsorb II ⁇ M+ >APTsorb II*M ⁇ -'- > APTsorb II*M ⁇ + or APTsorb II*Nay (0.657) > Raw peat (0.784) > APTsorb II*Cap+ (1.17) > APTsorb II*Fe3 ⁇ (17.5). This trend indicates the importance for the alkaline metal (+l) derivatives.
  • a lower value means that less of the cadmium cations in the influent aqueous solution remained in the solution and were adsorbed instead onto the APTsorb II*M granules— i.e., a high adsorption activity for the medium. Hence, a lower value is better.
  • Example 8 Determining the Breakthrough Capacity for Cadmium
  • APTsorb II, APTsorb II*Na, APTsorb III, and APTsorb III ⁇ Na were chosen as the most selective or the most active peat granular media according to the equilibrium tests. Since it was not possible to derive a selectivity coefficient for APTsorb II*Zn peat media using equilibrium test, the column test was the next choice.
  • the experimental setup for the column system consisted of a plastic column resulting in a bed size of 62 mm in diameter and approximately 50 mm deep, depending upon the wet density of peat medi a.
  • the wet density of each media was measured separately.
  • 72 g of peat material (particle size distribution between 10-50 mesh) were submerged in type I D.I. water (18.2 MOhm) for 10 hours to wet the surface of the granules and allow the granules to swell.
  • Plastic mesh was installed at both the top and the bottom of the column.
  • the column was packed with 20 mm of HCl-washed Red Flint filter gravel (granular size 3-5 mm) sourced from Red Flint Rock and Stone of Eau Claire, Wisconsin, and then with 72 g of pre- wetted peat media. Five bed volumes of type I D.I. water were pumped through the column prior to the testing solution.
  • Breakthrough behavior was evaluated by plotting the cadmium and zinc solution concentrations in the effluent as a function of the total number of bed volumes that had been treated.
  • the amount of cadmium ion adsorbed in the column was determined from the area above the breakthrough curve assuming the breakthrough happens when the concentration of cadmium in the effluent reaches 50 ppb.
  • the absorption capacity of the modified APTsorb granules was verified by digesting the spent granules and measuring the concentration of Cd2+ and Zn2+.
  • the breakthrough sorption capacity of the peat media was measured at two flow velocities of influent: 0.1 m/hr and 0.4 m/hr. Column data is presented in Table 9 and Figures 11-12.
  • APTsorb II*Na peat granular media exhibits the highest breakthrough capacity for cadmium cations in the column test, around 3.04 mg/g, which suggests that the equilibrium test is a suitable technique to measure the selectivity of cadmium sorption in the presence of zinc.
  • APTsorb III peat granules have the highest activity to sorb cadmium with lowest selectivity and, therefore, lowest breakthrough capacity— 0.47 mg/g.
  • APTsorb II peat media showed a higher capacity for sorption of cadmium ion (2.63 ing/g) compare to APTsorb III media.

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Abstract

La présente invention concerne un procédé de préparation d'un milieu de sorption granulé ou aggloméré à partir d'un matériau organique partiellement décomposé tel que la tourbe, suivi par une activation thermique à basse température du milieu de sorption pour produire un degré élevé de dureté de granules ou de pastilles équilibré avec un niveau efficace de capacité d'échange d'ions et d'adsorption, suivi par un traitement chimique du matériau de sorption par l'intermédiaire d'une solution présélectionnée de sels solubles (appelé "APTsorb II*Μ") pour utilisation dans un processus de traitement d'eaux usées dans lequel des cations métalliques toxiques en compétition sont présents dans les eaux usées.
PCT/US2017/019302 2016-02-24 2017-02-24 Milieu particulaire préparé à partir de matière organique partiellement décomposée pour sorption sélective entre des ions métalliques en compétition dans des solutions aqueuses WO2017147384A1 (fr)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110550723A (zh) * 2019-09-04 2019-12-10 湖南宇山玉月农业科技有限公司 一种处理畜禽废水的生物填料
CN114686332A (zh) * 2022-03-28 2022-07-01 山东工大食品科技有限公司 一种酱香型白酒新酒的脱色除杂工艺
CN115178237A (zh) * 2022-07-01 2022-10-14 北京科技大学 一种污水处理选择性吸附材料的制备方法

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Publication number Priority date Publication date Assignee Title
US5494649A (en) * 1991-10-03 1996-02-27 Cognis, Inc. Process for removing heavy metals from paint chips
US20090069176A1 (en) * 2002-07-26 2009-03-12 Mark Hernandez Removing metals from solution using metal binding compounds and sorbents therefor
US20140306148A1 (en) * 2013-03-15 2014-10-16 Regents Of The University Of Minnesota Particulate Sorption Medium Prepared From Partially Decomposed Organic Matter

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5494649A (en) * 1991-10-03 1996-02-27 Cognis, Inc. Process for removing heavy metals from paint chips
US20090069176A1 (en) * 2002-07-26 2009-03-12 Mark Hernandez Removing metals from solution using metal binding compounds and sorbents therefor
US20140306148A1 (en) * 2013-03-15 2014-10-16 Regents Of The University Of Minnesota Particulate Sorption Medium Prepared From Partially Decomposed Organic Matter

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110550723A (zh) * 2019-09-04 2019-12-10 湖南宇山玉月农业科技有限公司 一种处理畜禽废水的生物填料
CN114686332A (zh) * 2022-03-28 2022-07-01 山东工大食品科技有限公司 一种酱香型白酒新酒的脱色除杂工艺
CN114686332B (zh) * 2022-03-28 2024-01-23 山东工大食品科技有限公司 一种酱香型白酒新酒的脱色除杂工艺
CN115178237A (zh) * 2022-07-01 2022-10-14 北京科技大学 一种污水处理选择性吸附材料的制备方法

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