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
  • B01J47/00—Ion-exchange processes in general; Apparatus therefor
  • B01J47/10—Ion-exchange processes in general; Apparatus therefor with moving ion-exchange material; with ion-exchange material in suspension or in fluidised-bed form
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C18/00—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
  • C23C18/16—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by reduction or substitution, e.g. electroless plating
  • C23C18/1601—Process or apparatus
  • C23C18/1617—Purification and regeneration of coating baths
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D21/00—Processes for servicing or operating cells for electrolytic coating
  • C25D21/16—Regeneration of process solutions
  • C25D21/22—Regeneration of process solutions by ion-exchange
• • 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
  • C02F1/285—Treatment of water, waste water, or sewage by sorption using synthetic organic sorbents
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S210/00—Liquid purification or separation
  • Y10S210/902—Materials removed
  • Y10S210/911—Cumulative poison
  • Y10S210/912—Heavy metal

Definitions

• the present invention relates to the problem posed by the treatment of aqueous solutions loaded with heavy metals, inter alia of discharges of industrial aqueous effluents.
• acrylic superabsorbent polymers for water and aqueous solutions, in particular polyacrylic acids, when brought into contact with a solution containing multivalent metal ions begin to swell in significant proportions, then having fixed the multivalent ions, they reject part of their swelling water.
• This behavior has been applied for the purification of aqueous effluents before their discharge (see for example French patent application No. 93 06711).
• the swelling phenomenon is a factor in improving the kinetics of the absorption of ions on the polymer; however, it has the disadvantage of a considerable variation in the volume of the absorbent bed, which makes it impractical to use it in a column with a fixed bed.
• the present invention is based on the original idea that if a particulate superabsorbent is suspended in a vertical vein of a solution of multivalent ions animated in an upward movement such that the particles in their state of maximum swelling are in state of stationary dynamic regime, that is to say that they do not sediment or are entrained in the liquid vein, then all the particles which will be loaded with heavy ions will enter into sedimentation and will be recoverable at the bottom of the column.
• the invention thus consists of a process for lowering the content of multivalent cations in aqueous solutions by adsorption said heavy cations on a superabsorbent polymer, produced within a column fed at the head with a superabsorbent and at its base with the aqueous solution to be extracted, and exhausted at the head of the purified solution and at the foot of the enriched superabsorbent, characterized in that that the aqueous solution circulates in the body of the column with an upward movement whose speed is lower than the sedimentation speed of said superabsorbent when it is loaded with multivalent cation ions.
• the process is implemented in a column, the diagram of which is given in FIG. 1. It comprises a cylindrical body ⁇ mounted on a column base ⁇ surmounted by a flaring ®, which overflows on a circulation circuit ⁇ looped back to the column base and driven by a pump ®.
• the column base is extended by a cone or a tube ® with a volume of approximately 1.5 liters.
• the entire dead volume of the installation is first filled with solution to be purified by the inlet (L1).
• L1 solution to be purified by the inlet
• the system works as follows. Dry or wet SAP is introduced continuously at level (S1) via a plunging funnel ⁇ , from a hopper ⁇ .
• the liquid to be purified is introduced continuously at level (L1), while on the one hand the purified liquid overflowing at level (L2) and on the other hand the SAP saturated with heavy ions sedimented in the lower part ® of the column base.
• a wringing device ⁇ attached to the column or outside makes it possible to separate (S2) a drained SAP and a wringing liquid (L3) either recycled in (L1) or joined to the rejects (L2).
• a ® filter can also be inserted in the circulation circuit. The flow rate of the pump ⁇ is adjusted so that the rate of rise of the liquid in the column body corresponds to the steady state of the just swollen SAP particles.
• the aqueous solution in the column body leaves in the superabsorbent polymer the quantity of heavy ions corresponding to at least 60% of its capacity for absorption of heavy ions.
• the rate of fall of a SAP swollen in water or aqueous solutions that have approximately the same viscosity is about 20 meters per hour, and that of the same SAP saturated with nickel is about 75 m / h, and the operating point is that which corresponds to a pump flow activating a movement of liquid in the column body of 20 m / h. Similar volume variations are obtained during the complexation of copper and calcium.
• the SAPs useful for the invention are crosslinked polymers of acrylic or methacrylic acid or their alkaline salts, or their copolymers with other unsaturated monomers, said unsaturated monomers possibly being alkenes such ethylene, propylene or styrene, or other acrylic monomers such as acrylamide, or sulfonic acids, such as acrylamido-methylpropane sulfonic acid, or derivatives of acrylic or methacrylic acid having complexing functions metals, for example aspartic acid, iminoacetic acid functions, the latter being very effective when the aqueous solution to be treated contains strong metal complexing agents such as citric acid or EDTA, or their alkaline salts, etc.
• unsaturated monomers possibly being alkenes such ethylene, propylene or styrene, or other acrylic monomers such as acrylamide, or sulfonic acids, such as acrylamido-methylpropane sulfonic acid, or derivatives of acrylic or me
• These polymers are produced with a content of crosslinking agent of between 0.005% and 5%, and preferably between 0.01% and 5% by weight, relative to the sum of the constituent monomers. These are products insoluble in aqueous solutions, which, however, as soon as they are dispersed there, swell and thus absorb quantities of water of the order of 10 to more than 1000 g per g of polymer.
• Example 1 A column produced according to the diagram in FIG. 1 has a cylindrical body ⁇ with a diameter of 0.07 m and a height of about 1.20 m.
• the pump ⁇ operates at a speed such that the rising speed of the liquid in the column body is stabilized at 15-20 m / h. It is supplied, on the one hand with dry SAP (Aquakeep® 50 D from Elf Atochem SA, a SAP at 25% in acrylic form and 75% in sodium acrylate form) at a rate of 50 g / h and on the other hand share in nickel sulphate solution titrating 5 g of Ni ++ per liter at a rate of 2 l / h.
• An aqueous solution is withdrawn continuously at (L2) at a rate of 1 l / h, which now only titrates 0.1 g / l of nickel, and semi-continuously at the bottom of the column at an average of 1 kg / h. , a slurry of nickel-laden SAP which settles in the lower part of the column and which is separated into ⁇ into a SAP containing 0.2 g of nickel per gram of SAP introduced, directed to a reprocessing cell and in liquid impregnation which is a 0.1 g / l solution of nickel which is added to the effluents (L2).
• Example 2 (counterexample)
• the column is that which is described in Example 1 working under the conditions of Example 1 with the difference that the rate of rise of the liquid in the body of the column is set at 13 m / h .
• An aqueous solution which titers 0.25 g / l of nickel is withdrawn continuously at (L2) at the rate of 1 l / h.
• L2 0.1 kg / h of solid
• L3 0.9 kg / h of liquid
• Example 3 shows that with a lower rate of rise than in Example 1, the contact time between the superabsorbent and the solution to be depleted decreases and that the effectiveness of the superabsorbent degrades (0.25 g / l at L2 versus 0.1 previously).
• Example 3 (counterexample)
• the column is that which is described in Example 1 working under the conditions of Example 1 with the difference that: the rate of rise of the liquid in the body of the column is adjusted to 25 m / h.
• a quarter of the amount of SAP introduced is entrained in the recirculation loop by ⁇ and is stopped at the level of the filter ®.
• Example 4 Insertion of the device according to the invention in a chain for rinsing parts having undergone a chemical nickel-plating treatment.
• the example illustrates the interest which one finds in using SAP for:
• the treatment column according to the invention is adapted to the first rinsing tank which can be static or against the tide.
• flow rate (l / m 2 ): quantity of rinsing water used per m 2 of surface treated.
• Rd is the dilution ratio, that is to say the concentration ratio between the deposit bath, concentrated, and the last rinsing tank, the most diluted. This parameter is conventionally used by surface caterers. They admit, in general, that to have an effective rinsing, it is necessary Rrj> 1000. This naturally applies to each constituent of the bath.
• R'd (without SAP) is the dilution ratio obtained under the rinsing conditions considered (number of tanks, water flow rate, static or backwashing) without using SAP. Applies to all components of the bath.
• Rd (Ni) is the nickel dilution ratio obtained using the SAP column and possibly dispersed SAP. The SAP acting only on nickel (or other multivalent cation present), the dilution ratio of the other constituents of the nickel-plating bath (for example phosphites, organic acids, etc.) remains equal to Rd (without SAP).
• the process is mainly intended to lower the content of heavy ions in medium-strength aqueous solutions. It is possible, if necessary, to combine with this technique an additional treatment, for example a passage over ion exchange resins to bring these solutions to an almost zero level of heavy ion content.
• the present process will then find its full utility, the standard columns of ion exchangers directly treating effluents saturating too quickly to be technically and economically viable when the attack concentration of heavy ions is too high. POSSIBILITIES OF INDUSTRIAL APPLICATION.
• the process is of particular interest in chemical or electrolytic nickel-plating installations, where the problem arises of the evacuation of rinsing effluents from nickel-plated parts titrating a few hundred mg / l of nickel.
• effluents containing copper, zinc, chromium, cadmium and lead which can be present in the effluents of the industries of treatment of surface, or even to any other cation of the metals of groups IB, II B, III A, IV A, VI B, VII B and VIII of the periodic table (as found in the Handbook of Chemistry and Physics, CRC Press, 1980), to the extent that these cations cause sufficient density variations when fixed in SAPs.

Landscapes

• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Mechanical Engineering (AREA)
• General Chemical & Material Sciences (AREA)
• Electrochemistry (AREA)
• Life Sciences & Earth Sciences (AREA)
• Hydrology & Water Resources (AREA)
• Environmental & Geological Engineering (AREA)
• Water Supply & Treatment (AREA)
• Manufacture And Refinement Of Metals (AREA)
• Treatment Of Water By Ion Exchange (AREA)
• Treatment Of Liquids With Adsorbents In General (AREA)
• Removal Of Specific Substances (AREA)
• Solid-Sorbent Or Filter-Aiding Compositions (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=9466507

Family Applications (1)

Country Status (9)

Families Citing this family (7)

Family Cites Families (9)

• 1994
  • 1994-08-26 FR FR9410318A patent/FR2723935B1/fr not_active Expired - Fee Related
• 1995
  • 1995-08-08 CA CA002198505A patent/CA2198505A1/fr not_active Abandoned
  • 1995-08-08 CN CN95195683A patent/CN1160362A/zh active Pending
  • 1995-08-08 WO PCT/FR1995/001063 patent/WO1996006677A1/fr not_active Application Discontinuation
  • 1995-08-08 EP EP95927768A patent/EP0777528A1/de not_active Withdrawn
  • 1995-08-08 KR KR1019970701245A patent/KR970705438A/ko not_active Application Discontinuation
  • 1995-08-08 AU AU31688/95A patent/AU3168895A/en not_active Abandoned
  • 1995-08-08 JP JP8508526A patent/JPH10505275A/ja active Pending
  • 1995-08-08 US US08/793,461 patent/US5885462A/en not_active Expired - Fee Related

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events