Classifications

• • 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
  • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
  • B01D53/22—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by diffusion
  • B01D53/225—Multiple stage diffusion
  • B01D53/226—Multiple stage diffusion in serial connexion
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
  • B01D53/22—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by diffusion
  • B01D53/229—Integrated processes (Diffusion and at least one other process, e.g. adsorption, absorption)
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
  • B01D61/14—Ultrafiltration; Microfiltration
  • B01D61/145—Ultrafiltration
  • B01D61/146—Ultrafiltration comprising multiple ultrafiltration steps
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
  • B01D61/14—Ultrafiltration; Microfiltration
  • B01D61/18—Apparatus therefor
• • 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
  • C02F1/283—Treatment of water, waste water, or sewage by sorption using coal, charred products, or inorganic mixtures containing them
• • 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
  • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
  • C02F1/441—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by reverse osmosis
• • 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
  • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
  • C02F1/442—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by nanofiltration
• • 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
  • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
  • C02F1/444—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by ultrafiltration or microfiltration

Definitions

• the field of the invention is that of the treatment and purification of water and gases. More specifically, the present invention relates to a process for removing organic or inorganic compounds from gaseous or aqueous effluents and a device for its implementation, combining membrane filtration and adsorption on activated carbon.
• Membrane filtration in particular ultrafiltration, is a technique that is increasingly used today to retain high molecular weight molecules, bacteria or fine particles contained in aqueous or even gaseous effluents, these pollutants not being retained by the usual filters. This technique generally occurs at the end of effluent treatment and for refining.
• a first objective of the invention is to find a method and to implement a device for eliminating organic or inorganic compounds from gaseous or aqueous effluents allowing both efficient retention of molecules with high molecular weight and adsorption of smaller molecules.
• Another objective of the present invention is to avoid clogging and abrasion of the filtration membranes by the particles of the adsorbent.
• the process for removing organic or mineral compounds from gaseous or aqueous effluents according to the invention is therefore characterized in that it comprises a membrane filtration step (microfiltration, ultrafiltration or nanofiltration) followed by the passage of the permeate over or through at least one membrane based on activated carbon.
• the membrane filtration is rultrafiltration.
• conventional filtration is meant the retention of suspended particles larger than several micrometers.
• Membrane filtration has three types of separation depending on the size of the compounds. If the membrane retains particles whose size is a few micrometers (for example bacteria with a size of approximately 1 to 2 ⁇ m.), This is microfiltration.
• ultrafiltration for which the diameters of the pores of the membrane are between 0.001 and 0.1 ⁇ m, is reserved for the separation of compounds with a molar mass of 10,000 to 100,000 (or even 2,000 to 300,000) . Nanofiltration, even finer, concerns the separation of compounds having a molar mass greater than a few tens of grams.
• activated carbon in the form of a membrane eliminates the need to post-filter the effluent after adsorption.
• the activated carbon particles are retained by their rigid structure (activated carbon fibers or binder between the particles).
• These activated carbon membranes can therefore be used without problem downstream of an ultrafiltration stage, by treating the permeate, and therefore be used at the end of the treatment or purification chain.
• this membrane filtration permeate (for example rultrafiltration) consisting of the effluent being treated from which high molecular weight molecules, microorganisms, particles, etc. have already been eliminated. is much less loaded with organic or mineral matter: the adsorbent can therefore play its role at the maximum of these capacities without premature clogging of its surface or of the pores of the membrane based on activated carbon.
• the adsorption competitions that can take place between molecules or ions on the surface of the activated carbon are thereby considerably reduced, or even eliminated.
• Activated carbon membranes also have the advantage of easier regeneration.
• the device for implementing the method according to the invention is characterized in that it comprises one or more first filtration membrane (s) receiving the effluent to be treated and delivering a permeate practically free of substances with high molecular weight, the said first membrane being coupled to at least one second membrane based on activated carbon adsorbing the residual pollutants of the filtration permeate.
• the first membrane has an essentially filtration function, particularly for the retention of substances with high molecular weights. It receives the effluent to be treated, which passes through its pores, and delivers a permeate which is in turn brought into contact with the second membrane.
• This second membrane based on activated carbon, has an adsorption function for the small molecules and / or residual ions contained in the permeate.
• the nature of the first membrane, micro-, ultra- or nanofiltration, is indifferent. It can be a mineral membrane or an organic membrane, such as cellulose acetate or polyamide.
• the device according to the invention can comprise several membranes arranged in series or in parallel, of identical and different sizes and nature. It may advantageously include first filtration membranes placed in series and crossed by the effluent which meets increasingly reduced pore diameters.
• Microfiltration membranes retain suspended particles and bacteria, colloids if the medium is liquid.
• Ultra- and nanofiltration membranes remove molecules of high molecular weight from the effluent, in a range from 2,000 to 300,000.
• the filtration membrane (s) and the adsorption membrane (s) based on activated carbon are flat, a membrane based on activated carbon can be pressed against the part "downstream" of a first filtration membrane, or be separated from it by a gap.
• U such an interstice gives the permeate time to undergo some turbulence which thus favor the speed of transfer of the compounds present in the fluid towards the adsorbent by a reduction in the concentration gradient in the fluid.
• the thickness of the gap may be between 1 mm and several centimeters.
• the first filtration membranes consist of a cylindrical bundle of hollow fibers retained by a link or a macroporous coating. The effluent enters each fiber at one end, migrates inside the lengthwise direction of the cylindrical fiber, and by pressure on the fluid, releases the permeate perpendicular to the periphery.
• the adsorbent membrane (s) based on activated carbon envelop the bundle of hollow fibers forming the first membranes or each fiber individually.
• Such an envelope may for example be of cylindrical shape or made up of flat membrane (s) wound in a spiral.
• the second membrane based on activated carbon consists of activated carbon fibers. These fibers are obtained, for example, by calcination and activation (in an oxidizing medium at high temperature) of polyacrylonitrile fibers. Such fibers can be woven or pressed to form membranes resembling fabrics or felts.
• the second membrane based on activated carbon is a polyether or polyester foam loaded with grains of activated carbon retained by a binder.
• the second membrane based on activated carbon is a porous surface formed from an activated carbon powder and a binder.
• FIG. 1 presents an exploded diagram of the device according to a first variant of the invention, in which the two membranes, of filtration and adsorption, are planar
• FIG. 2 shows a view of the device according to a second variant of the invention, in which the adsorption membrane envelops a bundle of filtration membranes.
• FIG. 1 represents a mixed module of ultrafiltration and adsorption on a membrane based on activated carbon. The diagram of this figure shows a horizontal superposition of the various constituent elements, but it is obvious that these elements can be arranged vertically.
• This module (1) parallelepiped, here consists of an upper compartment (2) receiving the effluent (e) to be treated, separated at its lower part from the ultrafiltration membrane (3) by a seal (4).
• the adsorption membrane based on activated carbon (5) which is the same size as the ultrafiltration membrane (3), is either pressed against the latter (case of Figure 1), or be removed by the presence a second seal (4 ').
• the lower compartment (6) intended to receive the purified effluent (s): it supports the whole of a module (1) and is separated from the adsorption memrane (5) by a joint (4 ").
• the respectively lower and upper faces of the compartments (2) and (6) are pierced with slots (7) allowing better flow and good distribution of the fluid on the one hand on the surface of the ultrafiltration membrane (3) and d on the other hand at the entrance to the lower compartment (6).
• the effluent to be treated enters the upper part of the module (1) by the end piece (8) placed, for example, on the rear face of the upper compartment (2 ). It is distributed throughout the entire compartment (2) and, under the action of a pressure applied by pump or compressor systems (not shown in FIG. 1) (Relative pressure from 1 to 15 bars for example), is forced to pass through the ultrafiltration membrane (3).
• the fraction of the effluent (e) comprising the fluid itself and the compounds of size smaller than the pore diameters of the ultrafiltration membrane (3) passes through it and constitutes the permeate.
• the concentrate (c), which contains the repressed compounds (high molecular weight molecules, microorganisms, particles, colloids, etc.) leaves the upper compartment (2) by a second endpiece (9), preferably located on the opposite side to that which supports the end piece (8).
• This ultrafiltration concentrate (c) is either eliminated or recycled to return once or several times to the upper compartment (2) in contact with said ultrafiltration membrane (3).
• the permeate As for the permeate, it then comes into contact with the second membrane (5), based on activated carbon, which plays the role of an adsorbent of low molecular weight molecules remaining in the fluid.
• This porous membrane (5) is traversed by the fluid which arrives purified in the lower compartment (6) and is then evacuated by the nozzle (10).
• FIG 2 shows a device according to a second variant of the invention.
• the filtration membrane - here ultrafiltration - consists of a bundle of hollow fibers, ie cylindrical ultrafiltration membranes (1 retained by a macroporous coating (12), also cylindrical in shape.
• second membrane (5) based on activated carbon, is a cylindrical envelope surrounding the bundle of fibers hollow (11), the assembly being arranged inside a compartment (13) receiving the purified fluid (s) and evacuating it through the emb (10).
• the effluent (e) penetrates inside each hollow fiber (11), migrates in the arrows s (from left to right in FIG. 2), and releases the perm perpendicular to the periphery of each fiber. This permeate crosses the wall (12) then the second adsorbent membrane (5) to arrive in the final compartment (13).
• the concentrate (c) comes out to the right of the module (1). It can be recycled (following a recycling loop not shown).
• the aqueous effluent contains humic substances at a concentration of the order of 50 mg C / l and a micropollutant (phenol) at a concentration of 1 mg / 1. This corresponds to a mixture of molecules of high molecular weight (humic substances 1000 ⁇ M ⁇ 100,000) and low molecular weight (rism
• Table 1 Results of ultrafiltration tests of the mixture of Example 1 If the humic substances are very well arrested by the ultrafiltration membrane for cutoff thresholds of the order of - 1000 to 5000, it is not the same for the phenol which is is not eliminated by this process. The few percent eliminated during the crossing of the 1000 dalton membrane may come from a certain adsorption on the ultrafiltration membrane. On the other hand, the passage of ultrafiltrate over the membrane of activated carbon felt at a speed of approximately 2 m / h gives a total adsorption of the phenol (elimination of 100%) up to the maximum adsorption capacity of the felt which is found in the order of 130 mg phenol / g of activated carbon.
• Example 2 Under the same operating conditions as in Example 1, an aqueous effluent containing atrazine at 500 ⁇ g / 1, colloidal materials and suspended materials giving a turbidity of approximately 20 NTU was analyzed after treatment by coupling. Ultrafiltration - activated carbon fibers. The cutoff threshold for the ultrafiltration membrane was 10,000 daltons. The results show a total elimination of turbidity ( ⁇ 0.1 NTU) and a residual concentration of atrazine estimated at 2 ⁇ g ⁇ . These results were constant until the saturation of the activated carbon fibers which intervened for an amount of approximately 150 mg atrazine / g of activated carbon.
• This system as presented in the invention eliminates all of the pollution present in the effluent (small and large molecules).
• unlike the old methods which used granular or powdered activated carbon in the recirculation loop there is no adsorption competition in the raw effluent. Each process (filtration and adsorption) is here effective separately.
• the assembly does not require the addition of particulate activated carbon (in grain or powder) and is therefore very compact.
• the device used is as shown in FIG. 2. It comprises a tube with a circular section 2.4 cm in diameter and 0.9 m long perforated longitudinally with a bundle of 19 hollow fibers (diameter 3, 5 mm and length 0.90) lined internally with the filter membrane (thickness 10 to
• ultrafiltration membranes 15 ⁇ m).
• Several qualities of ultrafiltration membranes can be used depending on their pore diameter between 0.05 and 3 ⁇ m. In this example, an ultrafiltration membrane is used, the pore diameter of which is 0.1 ⁇ m.
• the tube, constituting the macroporous coating of the fibers ultrafiltration, is covered by a sleeve of microporous carbon felt with a specific surface of 1800 m 2 / g. The thickness of the felt is cm.
• the effluent to be treated is identical to that presented in Example 1.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Water Supply & Treatment (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• General Chemical & Material Sciences (AREA)
• Analytical Chemistry (AREA)
• Environmental & Geological Engineering (AREA)
• Organic Chemistry (AREA)
• Life Sciences & Earth Sciences (AREA)
• Hydrology & Water Resources (AREA)
• Separation Using Semi-Permeable Membranes (AREA)
• Water Treatment By Sorption (AREA)

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• 1994
  • 1994-09-27 FR FR9411625A patent/FR2724849A1/fr active Granted
• 1995
  • 1995-09-26 WO PCT/FR1995/001238 patent/WO1996009877A1/fr not_active Application Discontinuation
  • 1995-09-26 CA CA002200304A patent/CA2200304A1/en not_active Abandoned
  • 1995-09-26 AU AU35698/95A patent/AU695619B2/en not_active Expired - Fee Related
  • 1995-09-26 EP EP95932793A patent/EP0784500A1/de not_active Withdrawn
  • 1995-09-26 JP JP8511444A patent/JPH10506323A/ja active Pending

Non-Patent Citations (1)

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