Classifications

• • 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
  • B01J20/34—Regenerating or reactivating
  • B01J20/3408—Regenerating or reactivating of aluminosilicate molecular sieves
• • 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
  • C02F1/281—Treatment of water, waste water, or sewage by sorption using inorganic sorbents
• • 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
  • C02F2101/30—Organic compounds
• • 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
  • C02F2101/30—Organic compounds
  • C02F2101/32—Hydrocarbons, e.g. oil
  • C02F2101/322—Volatile compounds, e.g. benzene
• • 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
  • C02F2101/30—Organic compounds
  • C02F2101/34—Organic compounds containing oxygen
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2303/00—Specific treatment goals
  • C02F2303/16—Regeneration of sorbents, filters

Definitions

• the present invention relates to a process for the re- generation of synthetic zeolites used in the treatment of water contaminated by non-polar compounds .
• the invention relates to a process for the regeneration of synthetic, non-polar zeolites characterized by structural channels having specific dimen- sions, based on a thermal treatment carried out under particularly mild conditions.
• Non-polar zeolites characterized by a silica/alumina ratio > 50 are known as adsorbing materials for the treatment of water contaminated by non-polar compounds (WO 2003/002461 ⁇ .
• non-polar zeolites having structural channels with dimensions similar to those of the molecules of the contaminants to be eliminated, can be used for the treatment of water contaminated by halogenated solvents, aliphatic compounds, aromatic compounds or mix- tures thereof .
• zeolites and zeolite materials are also mentioned in literature as base components for the preparation of catalysts which can be used in numerous reactions of industrial interest .
• Zeolites can be used, for example, as catalysts in oxidation processes (US 4,410,501; US 4,794,198), in catalytic transposition reactions of oximes to amides [Catalysis Let- ters 17 (1993), 139-140; Catalysis Today 38 (1997), 249- 253] , in ammoximation processes (EP 958,861) .
• the exhausted zeolite-based catalysts are normally subjected to a regeneration process to eliminate the molecules involved in the chemical reactions contained in the struc- tural channels.
• the regeneration is carried out under drastic conditions due to the strong bonds which are formed between the molecules and zeolite.
• the regeneration is normally effected at high tempera- tures, ranging from 600 to 700 0 C, for 4-5 hours, in an at- mosphere containing oxygen at concentrations ranging from 0.1 to 4%.
• these zeolites can be effica- ciously regenerated by operating under particularly mild conditions. In practice, it is sufficient to provide a low amount of energy and a carrying gas to obtain the complete regeneration of the material.
• an object of the present invention relates to a process for the regeneration of non- polar adsorbing zeolites used for the treatment of contami- nated water, characterized in that the regeneration is effected at a temperature ranging from 250 to 350 0 C, for a time ranging from 0.5 to 1.5 hours, in the presence of an air flow ranging from 150 to 250 m 3 /hr.
• the regeneration is preferably effected within the temperature range of from 330 to 350 0 C, for a time ranging from 0.5 to 1 hr, in the presence of an air flow of 200 m 3 /hr.
• the regeneration conditions have been found in a 7 Ii- tre oven (figure 1) and verified in a rotating oven of 50 kg under an air flow (figure 2) .
• the oven can be filled with different quantities of zeolites so as to occupy from 20 to 60% of its volume, preferably from 40 to 50%.
• the heating of the oven can be effected at a heating rates ranging from 10 to 140 °C/min, preferably ranging from 50 to 100°C/min.
• the treatment processes of water contaminated by non- polar organic compounds envisage the circulation of the contaminated water through the zeolite system.
• the zeolite system has proved to be particularly effective with waters contaminated by toxic organic compounds coming from the petrochemical industry and from oil refining (organic solvents such as alkanes and chlorinated al- kenes, aromatic hydrocarbons such as BTEX) .
• Zeolites have also proved to be effective in the removal of compounds frequently associated in the underground water layers of the industrial sites considered, with the above-mentioned compounds, i.e. linear, branched or cyclic, oxygenated or non-oxygenated, aliphatic hydrocarbons, alkanes, alkenes, with concentrations ranging from 1,000 to 30,000 ppb.
• GROs Gas Range Organics - hydrocarbons from C 6 to C 9
• DROs Diesel Range Organics - hydrocarbons from Ci 0 to C 2 e
• These compounds are co-adsorbed in the structural channels, which represent the adsorption sites of the contaminants, contributing to the accumulation and immobilization within these structures of true organic contaminants.
• the zeolite When the water concentration at the outlet of the treatment system exceeds the target concentration, normally established within the legal limit allowed, the zeolite is considered exhausted and subjected to regeneration accord- ing to the process object of the patent.
• the efficacy of the regeneration of the invention process is evaluated by determining the organic carbon (Total Hydrocarbons Carbon, THC) eliminated by the zeolite during the treatment and, at the same time, by comparing the ad- sorbing capacity of the fresh adsorbing material and regen- erated material .
• THC Total Hydrocarbons Carbon
• Zeolites which can be suitably subjected to the regeneration process of the present invention are non-polar zeolites having a silica/alumina ratio > 50, characterized by structural channels having dimensions similar to those of the molecules of the contaminant compounds. Generally the channel dimension ranges from 4.5 to 10 A.
• Typical examples of these zeolites are silicalites, ZSM-5 zeolite, Mordenite, Beta Zeolite, Y Zeolite, MSA zeo- lites, ERS-8 and MCM-41.
• Zeolites which can be subjected to the process of the invention are zeolites obtained by synthesis (Carati, A., Bellussi, G., Mantegazza, M., and Guido Petrini . Process for preparing zeolites, EP 1614658 (A2) 2006-01-11) which can be in the form of microcrystals having dimensions ranging from 1 to 10 ⁇ m, as they appear after the preparation of the crystalline phase, or they can already be subjected to mixing and forming processes with suitable materials .
• Forming processes envisage the use of binders such as alumina, silica, clay for obtaining calibrated particles having a dimension ranging from 0.2 to 14 mm, therefore capable of ensuring a high permeability for functioning in a treatment system based on the adsorption of contaminants .
• the binder normally consists of 20/60% of the zeolite used.
• non-polar organic contaminants present in water treated with zeolites are: styrene, p- xylene, benzoanthracene, benzopyrene, benzofluoroanthrene, benzoperylene, chrysene, pyrene; halogenated solvents such as carbon tetrachloride, tetrachloroethylene, trichloro- ethylene, 1, 2-cis-dichloroethylene, 1,2-trans- dichloroethylene, 1, 1-dichloroethane, 1, 2-dichloroethane, hexachloroethane, hexachlorobutadiene , vinyl chloride, chloromethane, trichloromethane, 1, 1-dichloroethylene, 1,2- dichloropropane, 1, 1, 2-trichloroethane, 1,2,3- trichloropropane, 1 , 1 , 2 , 2-tetrachloroethane, monochloro
• the organic compounds taken into consideration were mainly MtBE and BTEX, which were quantitatively determined by means of headspace analysis according to the method EPA 5021.
• Oven column thermal program 50 0 C for 5 min, from 50 0 C to 180 0 C with an increase of 5.00°C/min, 180 0 C for 5 minutes. Description of the regeneration apparatus used.
• the figures indicate the concentration of the organic compounds measured at both the inlet of the treatment system with zeolites and at the outlet, removing ZSM-5 from the sample holder at the outlet of the filter 1, and also Mordenite at the outlet of the filter 3.
• GROs C 6 to C 9 hydrocarbons
• ZSM-5 is particularly suitable for the adsorption of small slightly po- lar molecules and Mordenite more suitable for the adsorption of hydrocarbons having greater dimensions (and also MtBE) .
• the specificity of ZSM-5 is more evident considering its action with respect to aromatic hydrocarbons having one ring (BTEX) , as indicated in the graph of figure 5. Even in the presence of an unstable feeding concentration, ZSM-5 effects the complete removal of BTEX aromatic hydrocarbons .
• the zeolites used in example 1 were considered exhausted and subjected to a regeneration process.
• the 7 litre cylindrical oven (figure 1) was filled with 1 Kg of ZSM-5 and heated up to 500 0 C with a heating gradient of 10°C/min.
• the rotation rate of the oven was 2 rpm.
• the air was introduced at a flow-rate of 2 m 3 /h.
• the permanence time at the temperature of 500 0 C was 10 minutes.
• the total time of the treatment was 60 minutes.
• the entity of organic carbon expelled from the zeolite was determined by THC with the variation of the temperature of the oven.
• the data are indicated in figure 8.
• Example 3 As for example 1 with 3 kg of ZSM-5.
• the THC data are indicated in figure 9. The test was carried out under the following conditions.-
• Air flow-rate 2 m 3 /hr
• Air flow-rate 2 m 3 /hr
• the maximum temperature was maintained for 20 minutes.
• the rotating oven heated to 300 0 C was filled with 50 Kg of ZSM-5.
• the rotation rate of the oven was 2 rpm.
• the air was introduced in countercurrent to the flow direction of the material at a flow-rate of 300 m 3 /hr.
• the total time of the treatment was 60 minutes.
• the comparison between fresh ZSM-5 and that regenerated according to example 8 was based on the comparison of the adsorption capacity of the two adsorbents. The results are indicated in figure 16 and clearly show the effect of the regeneration.

Landscapes

• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Inorganic Chemistry (AREA)
• Life Sciences & Earth Sciences (AREA)
• Hydrology & Water Resources (AREA)
• Engineering & Computer Science (AREA)
• Environmental & Geological Engineering (AREA)
• Water Supply & Treatment (AREA)
• Analytical Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Solid-Sorbent Or Filter-Aiding Compositions (AREA)
• Water Treatment By Sorption (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=39762397

Family Applications (1)

Country Status (3)

Families Citing this family (2)

Family Cites Families (4)

• 2007
  • 2007-06-22 IT ITMI20071264 patent/ITMI20071264A1/it unknown
• 2008
  • 2008-06-10 WO PCT/EP2008/004722 patent/WO2009000429A1/en active Application Filing
  • 2008-06-10 EP EP08773402A patent/EP2164628A1/de not_active Withdrawn

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events