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
  • C02F1/72—Treatment of water, waste water, or sewage by oxidation
  • C02F1/78—Treatment of water, waste water, or sewage by oxidation with ozone

Definitions

• the present invention relates to a process for the degradation of organic compounds in water, which has a TOC of more than 2 ppm and also contains dissolved carbonic acid or carbonates, by treatment with ozone and a
• WO 9708101 describes the treatment of industrial waste water with ozone in
• EP-A 634465 describes the purification of industrial waste water with ozone in a two-stage process, in particular aromatic compounds being broken down.
• EP-A 378994 describes the breakdown of aromatic impurities in industrial wastewater by ozone at elevated pressure and temperature.
• TOC Total Organic Carbon
• Water which has a TOC of more than 2 ppm and also contains dissolved carbonic acid or carbonates is e.g. known from polycarbonate production.
• dihydroxydiarylalkanes are used in the form of their alkali salts dissolved in water with phosgene in the heterogeneous phase in the presence of inorganic bases such as e.g. Sodium hydroxide solution and an organic solvent in which the product polycarbonate is readily soluble.
• inorganic bases such as e.g. Sodium hydroxide solution and an organic solvent in which the product polycarbonate is readily soluble.
• the aqueous phase is distributed in the organic phase.
• the interfacial process separates the polycarbonate in the form of its solution in the organic solvent used in the synthesis, for example methylene chloride.
• the remaining aqueous phase is advantageously from volatile organic impurities such.
• B. Remains of the organic solvent used in the synthesis, for example methylene chloride, freed what z. B. can be done by distillation. Waste water then remains with a high content of dissolved carbonates (for example 0.3 to 1.5% by weight) and with a high content of dissolved common salt (for example 4 to 12
• the wastewater is contaminated with organic compounds such.
• B. with phenols eg unsubstituted phenol or alkylphenols or arylphenols or
• Bisphenols such as B. bisphenol A) or amines (e.g. triethylamine or ethyl piperidine).
• the carbonates arise z. B. by the hydrolysis of the phosgene as a side reaction of polycarbonate production.
• the sodium chloride dissolved in the wastewater of polycarbonate production using the phase boundary process is a valuable raw material.
• a conceivable utilization of the sodium chloride load in the wastewater of the polycarbonate production according to the phase boundary process is the use of the sodium chloride for the production of chlorine and sodium hydroxide solution by electrolysis.
• this possibility has so far failed due to the other components, in particular the organic components of the waste water from polycarbonate production using the phase interface process.
• the particularly advantageous membrane process of chlor-alkali electrolysis requires pure aqueous sodium chloride solutions as the starting material.
• this aqueous solution must contain a low content of organic impurities, preferably the TOC of the saline solution must be less than 1 ppm. Even if the TOC of the saline solution is less than 1 ppm, organic impurities may still be present to a small extent in the saline solution, which impair the electrolysis process, e.g. B. by the service life of essential system components, such as of the membranes in the case of the membrane process. All this applies in particular to the membrane process for sodium chloride electrolysis, in which the service life of the membranes is an essential factor that determines the economy.
• wastewater other than that from polycarbonate production is also known, which is characterized in that it contains dissolved carbonates or carbonic acid.
• carbonates or carbonic acid dissolved in water hinder the removal of organic compounds from the water by treatment with ozone, because carbonate acts as a radical scavenger and thus hinders the breakdown of organic compounds via radical intermediates, as reported by Hoigne and Bader in Wat Res , Volume 10, 1976, pages 377 ff and Gurol and Watistas m Wat Res, Volume 21, 1987, pages 895 to 900
• the present invention is therefore based on the object of providing a process for reducing the content of organic compounds in water which contains dissolved carbonic acid or carbonates
• the present invention is also based on the object of providing a process for reducing the content of organic compounds in the water which contains dissolved carbonic acid or carbonates to such a small extent, that in
• Water dissolved table salt can be used to produce Chloi by electrolytic processes
• the task according to the invention is solved by a process / treatment of water which has a TOC of more than 2 ppm and contains at least 0.01% by weight of dissolved coal sauce or caibonates, with ozone, characterized in that the treatment is carried out at a temperature of 10 to 130 ° C and at an absolute pressure of 0.5 to 3 bar and that the water which is fed to the process has a pH of 2 to 1 1 and that the treatment over a period of 1 minute to 10 hours.
• the water treated according to the invention if it contains dissolved common salt, can be used to produce chlorine and sodium hydroxide solution by electrolysis of the common salt.
• the chlorine can be produced by the known membrane process. The process is not impaired by any impurities that may still be present in very low concentrations; in particular, the service life of the membranes is the same compared to the use of saline solutions, which are obtained by dissolving saline in completely pure water.
• the process according to the invention for the treatment of water with ozone is particularly economical, not technically complex and environmentally friendly. No high excess pressure is required. No catalyst is required. No UV radiation is required. There are no other chemicals, such as B. hydrogen peroxide, required. Of course, these measures can also be carried out.
• the process according to the invention allows the TOC in water to be reduced to below 1 ppm.
• the water treated with ozone according to the invention is also so pure that it can be discharged directly into surface water without the need for further purification.
• This provides an economical and ecologically favorable way of processing and disposing of water that has a TOC of more than 2 ppm and also contains dissolved carbonic acid or carbonates.
• the TOC of the water before the treatment with ozone is more than 2 ppm, preferably more than 5 ppm, particularly preferably more than 10 ppm.
• the TOC is determined in accordance with DIN 38 409-H 3 using the TOC 500 device from Shimadzu by measuring the content of inorganic carbon (TIC) and the content of inorganic or organic carbon (TC) of the water sample.
• TIC inorganic carbon
• TC inorganic or organic carbon
• a constant flow of high-purity, carbon dioxide-free air serves as the carrier gas.
• TC measurement a defined amount of the sample to be analyzed is injected into the TC combustion tube and burned there at 680 ° C on a TC catalyst. After cooling and drying, the resulting carbon dioxide is detected in an infrared analyzer.
• the sample is acidified with phosphoric acid and the resulting carbon dioxide is expelled from the sample and detected as above.
• the content of carbonic acid or carbonates in the water is at least 0.1% by weight calculated as carbonate (CO 3 " ). It is preferably at least 0.3% by weight, particularly preferably at least 1.0% by weight.
• the treatment according to the invention with ozone takes place at a temperature of 10 to 130 ° C, preferably at 20 to 100 ° C, particularly preferably at 60-90 ° C.
• the treatment according to the invention with ozone takes place at an absolute pressure of 0.5 to 3 bar, preferably from 1 to 2 bar, particularly preferably at 1.2 to 1.8 bar.
• the water which is fed to the process according to the invention for treatment with ozone has a pH of 2 to 11, preferably it has a pH of 3 to 11, particularly preferably it has a pH of 5 to 9 , very particularly preferably it has a pH of 5.5 to 7.
• the pH is measured at 20 ° C.
• a particularly preferred embodiment of the invention is given by the fact that the pH of the water which is fed to the process for treatment with ozone is less than 7 and has a value such that after the treatment of the water with ozone it has a value above 7.5 has. This change in the pH value from the acidic to the basic range in the course of the treatment with ozone leads to a particularly effective breakdown of the TOC in the water.
• the treatment according to the invention with ozone takes place over a period of 1 minute to 10 hours, preferably from 6 minutes to 2 hours, particularly preferably from 10 minutes to 60 minutes.
• a preferred embodiment of the present invention is a method in which, after the ozone treatment of the water, the water is subsequently fed to the electrolysis for the production of chlorine.
• the electrolysis is preferably carried out by the membrane process.
• the water which is subjected to the treatment with ozone according to the invention contains, for example, 2 to 20% by weight of common salt. It preferably contains 4 to 12% by weight of common salt.
• the water which is subjected to the treatment with ozone according to the invention is preferably the wastewater from polycarbonate production by the phase interface process, particularly preferably it is wastewater from the production of bisphenol A polycarbonate by the phase interface process.
• the temperature of the water which is supplied to the treatment with ozone can, for example, be set to the desired value with the aid of a heat exchanger.
• the pH of the water added to the treatment with ozone can be adjusted, for example, by adding an acid such as e.g. Hydrochloric acid or an alkali such as B. sodium hydroxide solution to the desired value.
• an acid such as e.g. Hydrochloric acid or an alkali such as B. sodium hydroxide solution to the desired value.
• the mixing of the water with the ozone generated in the ozone generator should be carried out as intensively as possible for optimal reaction control.
• any form of gas distribution is possible, e.g. the use of ultrasound, glass frits or conventional injectors.
• the oxidation of the wastewater with ozone is preferably carried out in a continuous process, with a plurality of reaction columns preferably being connected in series.
• a partial stream of the freshly produced ozone is preferably passed directly to the columns following the first column.
• a preferred embodiment of the invention is given in that at least two, in particular three, reaction columns for treatment with ozone are introduced. and that the ozone distribution varies between a distribution of 1: 1 or 1: 1: 1 (volume flow of the 1st column: volume flow of the 2nd column) per column up to 5: 1 or 5: 1: 1.
• the ozone distribution in the reaction columns is preferably 80% in the first column (s) and 20% in the last column.
• Possibly occurring peak loads of the TOC in the water can be adsorbed, for example, by an adsorber column, which is connected upstream of the system for treatment with ozone, and can be supplied to the treatment with ozone in a controlled manner under normal operating conditions.
• the adsorber column is preferably only used for
• the adsorber column is preferably constructed as follows.
• the adsorber column is cooled in the jacket by water. This sets an operating temperature of 15 ° C.
• the adsorber column is filled with adsorbers which adsorb phenol and bisphenol well and, depending on the pH, also desorb again, for example and preferably a microporous, non-functionalized, hydrophilic, hyper-crosslinked copolymer based on styrene and divinylbenzene or activated carbon as adsorber.
• the process according to the invention can be used, for example, to treat the waste water from the production of polycarbonate using the phase interface process.
• the cleaned wastewater can then be used to recover the common salt contained in the water for the production of chlorine by electrolysis. It is advantageous to determine the concentration of salt in the water, for example
• 4 to 12 wt .-% can be increased by adding solid table salt to a concentration of 20 to 30 wt .-%, preferably 25 wt .-%, before the water is fed to the electrolysis.
• the chlorine produced in the electrolysis and the sodium hydroxide solution can be fed back to the process for the production of polycarbonate by the phase-surface process after the chlorine has been added Carbon monoxide was converted to phosgene and the sodium hydroxide solution was used, for example, to produce bisphenolate solutions.
• the organic compounds that make up the TOC pollution of the water can be any organic compounds. These can be both aliphatic and aromatic compounds. The compounds can contain any heteroatoms.
• the organic compounds consist essentially of phenols (e.g. unsubstituted phenol or alkylphenols or arylphenols or bisphenols such as e.g. bisphenol A) and amines (e.g. triethylamine, ethylpiperidine).
• the ozone used in the process according to the invention is produced by known processes, for example from air or from oxygen. This creates mixtures of ozone in air or in oxygen, which contain, for example, 40 to 150 g of ozone per cubic meter of gas and which can be used as such. Higher
• Concentrations of ozone can be generated by special enrichment methods (adsorption or desorption processes).
• Unused ozone e.g. B. is contained in the exhaust gas of the system for treating the water with ozone, can be thermally or catalytically decomposed in a residual ozone destroyer.
• a treatment with hydrogen peroxide is additionally carried out before, during or after the treatment with ozone.
• Treatment is preferably carried out with
• treatment is additionally carried out with hydrogen peroxide and with UV radiation.
• the treatment with hydrogen peroxide and with UV radiation is preferably carried out simultaneously with the
• FIG. 1 The invention is explained below with reference to a drawing showing a preferred embodiment (FIG. 1).
• the water is brought to the desired temperature by the heat exchanger 1.
• the adsorber column 2 is only flowed through when the TOC content is exceptionally high. Appropriate valves are available for this. If the TOC content is low, the adsorber can also be flowed through to desorb the TOC again.
• the appropriately tempered water becomes
• the ozone 8 and 9 serve to condense any water that has been entrained (stripped) with the gas flow.
• the ozone is generated from oxygen in the ozone generator 10 and mixed with the waste water via a nozzle 11 and 12 at the entrance of the columns. Unused ozone is thermally destroyed in the residual ozone destroyer 13, preferably at 250 to 300 ° C.
• the water which was fed to the process contained 4 to 12% by weight of common salt and 0.3 to 1.5% by weight of carbonate.
• the TOC values of the water are given in the tables.
• the TOC resulted essentially from phenol and bisphenol A.

Landscapes

• Life Sciences & Earth Sciences (AREA)
• Hydrology & Water Resources (AREA)
• Engineering & Computer Science (AREA)
• Environmental & Geological Engineering (AREA)
• Water Supply & Treatment (AREA)
• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Treatment Of Water By Oxidation Or Reduction (AREA)
• Water Treatment By Electricity Or Magnetism (AREA)
• Removal Of Specific Substances (AREA)
• Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)

Priority Applications (9)

Applications Claiming Priority (2)

Publications (1)

Family

ID=7911718

Family Applications (1)

Country Status (14)

Cited By (14)

Families Citing this family (17)

Citations (1)

Family Cites Families (23)

• 2000
  • 2000-06-06 BR BR0011747-1A patent/BR0011747A/pt not_active IP Right Cessation
  • 2000-06-06 HK HK02109357.6A patent/HK1047738A1/zh unknown
  • 2000-06-06 KR KR1020017016176A patent/KR20020010714A/ko not_active Withdrawn
  • 2000-06-06 AU AU58117/00A patent/AU5811700A/en not_active Abandoned
  • 2000-06-06 AT AT00943769T patent/ATE260224T1/de not_active IP Right Cessation
  • 2000-06-06 CA CA002375245A patent/CA2375245A1/en not_active Abandoned
  • 2000-06-06 ES ES00943769T patent/ES2215682T3/es not_active Expired - Lifetime
  • 2000-06-06 DE DE50005436T patent/DE50005436D1/de not_active Expired - Lifetime
  • 2000-06-06 WO PCT/EP2000/005166 patent/WO2000078682A1/de not_active Ceased
  • 2000-06-06 CN CN00809148XA patent/CN1217864C/zh not_active Expired - Fee Related
  • 2000-06-06 JP JP2001504857A patent/JP4641691B2/ja not_active Expired - Fee Related
  • 2000-06-06 RU RU2002101017/15A patent/RU2244689C2/ru not_active IP Right Cessation
  • 2000-06-06 EP EP00943769A patent/EP1200359B1/de not_active Expired - Lifetime
  • 2000-06-12 TW TW089111364A patent/TW483871B/zh not_active IP Right Cessation

Patent Citations (1)

Also Published As

Similar Documents

Legal Events