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
  • C02F1/28—Treatment of water, waste water, or sewage by sorption
  • C02F1/281—Treatment of water, waste water, or sewage by sorption using inorganic sorbents
• • 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
  • B01J20/06—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising oxides or hydroxides of metals not provided for in group B01J20/04
• • 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
  • B01J20/28—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties
  • B01J20/28002—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties characterised by their physical properties
  • B01J20/28004—Sorbent size or size distribution, e.g. particle size
• • 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
  • B01J20/28—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties
  • B01J20/28014—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties characterised by their form
  • B01J20/28016—Particle form
• • 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
  • B01J20/3433—Regenerating or reactivating of sorbents or filter aids other than those covered by B01J20/3408 - B01J20/3425
• • 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
  • B01J20/345—Regenerating or reactivating using a particular desorbing compound or mixture
  • B01J20/3475—Regenerating or reactivating using a particular desorbing compound or mixture in the liquid phase
• • 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
  • C02F1/008—Control or steering systems not provided for elsewhere in subclass C02F
• • 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
• • 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
  • C02F2103/02—Non-contaminated water, e.g. for industrial water supply
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2209/00—Controlling or monitoring parameters in water treatment
  • C02F2209/40—Liquid flow rate
• • 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
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2305/00—Use of specific compounds during water treatment
  • C02F2305/02—Specific form of oxidant
  • C02F2305/023—Reactive oxygen species, singlet oxygen, OH radical

Definitions

• TITLE Water treatment process intended to reduce their dissolved silica content
• the invention relates to a method of treating water intended to reduce the content thereof in dissolved silica.
• the invention relates to such a process in which the dissolved silica is adsorbed on a regenerable adsorbent material.
• Silicon (Si) is present in many rocks and sediments. Through various chemical alteration processes, this element is found in many types of water (sea water, brackish water, water from rivers and lakes, etc.). Although the chemistry of silicon in water is complex and poorly understood, it is known that silicic acid is found in soluble form (“dissolved silica”) in these waters in concentrations that vary depending in particular on the chemical species they contain. contain and their temperature. Now, this dissolved silica has a certain number of drawbacks when it is desired to use such water for certain applications.
• this dissolved silica can precipitate under certain conditions and thus cause malfunctions of certain equipment using this water.
• dissolved silica can precipitate and scale or clog the equipment.
• This dissolved silica can also constitute a troublesome species as such, not because it can precipitate but because it will disturb by its presence certain chemical or physico-chemical reactions involved in the treatment of certain water.
• the presence of silica generates colloidal impurities in certain liquid-liquid extraction processes which greatly disturb the phase separation.
• Another example is the interfering nature of silica dissolved in chelating resin processes aimed at eliminating other compounds.
• the invention which relates to a method for treating water with a view to reducing the dissolved silica content, characterized in that it comprises at least one adsorption step consisting in making said water transit.
• a reactor accommodating an adsorbent granular material consisting of grains of iron (III) hydroxide and / or iron (III) oxyhydroxide and at least one power regeneration step adsorbent of said granular material comprising contacting said granular material with a base and at least one chloride.
• the invention therefore proposes to use such a material to adsorb dissolved silica and, when its adsorbing power with regard to this chemical species is insufficient, to regenerate this adsorbing power by bringing it into contact with a basic solution and a solution. of at least one chloride.
• the medium (s) containing these species can / can be used several times, until their silica content (s) is, or is estimated, too high.
• the cost of the process in terms of chemical reagents is low compared to the techniques of the prior art.
• At least part of said adsorbent granular material is in the form of akaganeite.
• Akaganeite is an inorganic form of iron (III) hydroxide with the formula b-Fe 3+ 0 (OH, CI). This material is known to adsorb silica (Naren et al. Adsorption Kinetics of silicilic acid on akaganeite 2013 J. Colloid Interface Sci. 399 - 2013 87-91) but this property has never been implemented at the industrial stage because no efficient regeneration method making it possible to maintain its adsorption performance was not known.
• said granular material contains at least 5% by weight of akaganeite.
• the inventors have observed that the use according to the invention of a base and of at least one chloride to regenerate the adsorbing power of the granular material made it possible to maintain, or even improve, this adsorbing power.
• the base and said at least one chloride may be used concomitantly or successively.
• said regeneration step is carried out with a regeneration solution containing said base and said at least one chloride.
• the regeneration step is carried out with two regeneration solutions, one containing said base, the other containing said chloride.
• the solution containing said at least one chloride can then be used before or after that containing the base.
• said base is chosen from the group consisting of NaOH, KOH, NH 4 OH, LiOH.
• NaOH is used.
• said chloride is chosen from the group consisting of NaCl, KCl, LiCl, NH 4 Cl, MgCl 2 , CaCl 2 , BaCl 2 , MnCl 2 .
• NaCl is used.
• the base will be used with a molarity between 0.1 and 4 N, preferably between 0.5 and 2 N and the chloride will also be used with a molarity between 0.1 and 4 N, preferably between 0.5 and 2 NOT.
• said granular material is used in a fixed or fluidized bed and said adsorption step is carried out according to a volume load of between 5 and 30 BV / h (“bed volume per hour”), ie between 5 and 30 cubic meters of water passing through per cubic meter of granular material per hour.
• BV / h bed volume per hour
• said grains have a size of between 0.2 mm and 5 mm.
• the process according to the invention may be implemented with a granular material in the form of a fixed or fluidized bed or in an installation comprising an infinitely mixed reactor followed by a settling tank, said installation then being advantageously equipped with a pipe for recycling granular material settled in the reactor and means making it possible to bring a part of the granular material extracted from the settling tank into contact with said base and said at least one chloride before returning the regenerated material to the reactor.
• FIG 1 shows a schematic view of an installation for implementing the method according to the invention
• FIG 2 is a graph indicating the change in the adsorbing power of the granular bed of the installation according to Figure 1 after a regeneration step according to the invention (top curve) and two regeneration steps outside the invention (two curves of the invention. low).
• a water treatment installation comprises a tank 1 of water to be treated, a reactor 2 containing the adsorbent granular material 3, a tank of treated water 4 and a tank of regeneration solution 5.
• the water tank to be treated 1 is connected by a pipe 1a equipped with a valve lb to the upper part of the reactor 2, and the treated water tank 4 is connected to the lower part of the reactor 2 by a pipe 4a equipped. a valve 4b.
• the regeneration solution tank 5 is for its part connected to the lower part of the reactor 2 by a line 5a equipped with a valve 5b and a pump 5c and the upper part of the reactor 2 is connected by a recycling line 5e to this regeneration solution tank 5. Finally, this regeneration solution tank 5 comprises an evacuation pipe 5d.
• the height of the granular adsorbent bed 3 in the reactor 2 may vary according to the embodiments and that it will generally be between 0.5 m and 2 m.
• the granular bed 3 is composed of grains of 0.2 mm to 5 mm of iron oxyhydroxide containing at least 5% by weight of akaganeite.
• valves lb and 4b are open so as to allow the latter to flow through the pipe la in the reactor 2 according to a downward flow and thus come into contact with the adsorbent granular material 3.
• the treated water is collected in the tank 4 through the pipe 4a. It will be noted that in other embodiments, it could just as well be considered to pass the water to be treated in the reactor in an ascending flow.
• This adsorption step is carried out with a volume load of between 5 and 30 BV / h (“bed volume per hour”), ie between 5 and 30 cubic meters of water passing through per cubic meter of granular bed and per hour.
• the granular adsorbent bed gradually becomes loaded with silica and its adsorbing power decreases.
• valves 1b then 4b are closed so as to interrupt the transit of water to be treated in the reactor.
• a step for regenerating the adsorbing power of the granular bed 3 can then be implemented.
• a regeneration medium is produced.
• a 1N sodium hydroxide solution NaOH was used in which 50 g / L of 0.86 N sodium chloride NaCl were dissolved.
• the valve 5b is then open and the pump 5c started up to inject this regeneration solution into the adsorbent granular bed 3.
• the regeneration solution then passes through the granular bed and is recovered in the upper part of the reactor 2 via the line 5e recycling which allows it to be redirected to the reservoir 5.
• the silica adsorbed on the iron oxyhydroxide grains containing at least 5% by weight of akaganéite is transferred into the regeneration solution .
• the pump 5c is cut off and the valve 5b is closed, then the valves lb and 4b are re-opened to begin a new adsorption step.
• the process according to the invention is not very greedy in reagents (base and chloride).
• the graph of FIG. 2 is plotted on the abscissa the volume load in BV / h and on the ordinate the adsorbing power of the adsorbent granular bed in milligrams of Si0 per gram of adsorbent material.
• the top curve reflects the adsorbing power of the granular bed after regeneration according to the invention with the regeneration medium described above made from IN NaOH and 50 g / L of NaCl at 20 ° C, while that the two lower curves reflect the adsorbing power of an identical granular bed after regeneration with a medium of regeneration containing IN NaOH but not containing chloride, at 20 ° C (lower curve) and at 50 ° C (middle curve).
• the regeneration of the adsorbent bed is notably better when, according to the invention, chloride ions are present in the regeneration solution. Even by heating the regeneration solution containing only NaOH to 50 ° C., the regeneration performance of the adsorbent bed remains lower than that observed with the regeneration solution produced, according to the invention, from NaOH and NaCl.
• the process according to the present embodiment was carried out with a water to be treated containing 300 mg of dissolved silica per liter.
• the amount of silica adsorbed on the adsorbent material was measured after the first, seventh and eighth regeneration cycle with the regeneration solution containing chloride and base.
• the results are given in Table 1 below. These results also show that, unexpectedly, the adsorbing power of the granular material increases with the number of regeneration cycles recommended according to the invention.
• a method according to the invention applied to a water to be treated containing a dissolved silica concentration of between 70 mg (Si0 2 ) / L and 100 mg (Si0 2 ) / L also showed an increase in the adsorbing power of the granular material with the number of regeneration cycles according to the invention, with values close to those presented in Table 1.

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

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

Country Status (10)

Family Cites Families (11)

• 2019
  • 2019-07-12 FR FR1907868A patent/FR3098511B1/fr active Active
• 2020
  • 2020-07-13 MY MYPI2021007336A patent/MY209249A/en unknown
  • 2020-07-13 AR ARP200101958A patent/AR119394A1/es active IP Right Grant
  • 2020-07-13 WO PCT/EP2020/069778 patent/WO2021009130A1/fr not_active Ceased
  • 2020-07-13 CN CN202080050514.1A patent/CN114144381A/zh active Pending
  • 2020-07-13 EP EP20739681.3A patent/EP4178919A1/de active Pending
  • 2020-07-13 MX MX2021015472A patent/MX2021015472A/es unknown
  • 2020-07-13 US US17/620,897 patent/US12434983B2/en active Active
  • 2020-07-13 AU AU2020315125A patent/AU2020315125B2/en active Active
• 2021
  • 2021-12-13 CL CL2021003330A patent/CL2021003330A1/es unknown

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