Ion exchange-type gel membrane for decolorizing printing and dyeing wastewater and preparation method thereof

Abstract

The invention discloses an ion exchange type gel film for decolorizing printing and dyeing wastewater and a preparation method thereof. The prepared gel film has the characteristics of high flux, lowresistance and biodegradability. Continuous and uniform pores are formed from the surface to the interior of the gel film; due to the capillary action of the pores, high-speed sewage treatment can berealized, and subsequent pore-forming reprocessing is not needed, so that the gel membrane is easy to be used in pilot plant test and large-scale production, and can be directly used for filtering, adsorbing and decoloring printing and dyeing wastewater. The dye adsorption capacity can reach 80 mg/g to 600 mg/g, the decolorization rate is larger than 95%, and the total COD removal rate is larger than 85%.

Description

technical field [0001] The invention relates to the technical field of printing and dyeing wastewater treatment, in particular to an ion-exchange gel membrane for decolorization of printing and dyeing wastewater and a preparation method thereof. Background technique [0002] The printing and dyeing wastewater industry is different from other industries. The output of wastewater in the production process is particularly large, and the treatment is more complicated. In the industrial process, the suspended particles in the printing and dyeing wastewater are first flocculated and settled by flocculation to remove suspended solids; secondly, dissolved organic matter is removed through a series of unit operations such as biological oxidation and adsorption. However, a small amount of organic dyes exists uniformly in water in the form of a true solution, and the removal of dissolved organic dyes has become a research hotspot and difficult problem. [0003] The existing methods fo...

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Problems solved by technology

[0004] 1. Biological oxidation is a traditional process for removing organic dyes from printing and dyeing wastewater. Under the action of biological bacteria, aeration makes the organic dyes in the water fully contact with oxygen to achieve the purpose of organic oxidation, thereby removing organic pollutants in the solution. However, the operation of this process is cumbersome, and suitable biological bacteria need to be cultivated, and auxiliary processes such as aeration and biofilm require high equipment costs;

[0005] 2. The adsorption method is a relatively broad-spectrum method among many methods. The basic principle is that the adsorption medium has a relatively high relative area, so that organic dyes can be adsorbed by reducing the surface energy of the adsorption medium in printing and dyeing wastewater. Common adsorption Media such as activated carbon, adsorption resin, etc. In recent years, functional adsorption materials have also been applied to the adsorption treatment of printing and dyeing wastewater, such as ion exchange resins, graphene oxide composite materials, etc. The characteristic groups of functional adsorption materials can effectively capture dissolved organic matter in water. Dyes, however, the problem of adsorbent materials is that (1) although activated carbon and adsorption media have a relatively high relative area, the internal pores are between 0 and 1 μm, or even below 10 μm. -9 m level, the adsorption method is mainly static adsorption, if the dynamic adsorption method is adopted, the flow resistance is too large and it is difficult to realize large-scale treatment; (2) ion exchange resins and functional adsorption materials are mostly granular, and need to be cleaned before use. Swelling, cleaning, filling and other series of operation steps. In addition, the mass transfer efficiency of granular resin is relatively high due to the irregular and continuous distribution state formed by the gaps (0.1-2 mm) between the stacked particles and the internal pores (0-1 μm) of the particles. Low;

[0006] 3. An effective means to increase the processing capacity of the adsorbent material is to make the adsorbent material into a porous material. The preparation process and existing problems of the existing porous adsorbent material are as follows: (1) Freeze-drying method and freeze-induced phase separation technology in rich On the basis of the high molecular polymer gel containing a large amount of water, the whole is completely frozen, and then the pressure of the system is lower than the saturated vapor pressure of ice at the freezing temperature, so as to promote the overall sublimation of the crystallized ice cube and leave pores inside the gel. The preparation process takes a long time, and the pore-forming time exceeds 24 hours. The freezing needs to be in a negative pressure environment to sublimate the ice. The system pressure is under 5-20kPa for a long time, which requires high pressure resistance for the preparation equipment. Pores are first formed, and finally the inside of the gel forms pores, and the prepared porous water-absorbing polymer pores are uneven; (2) the necessary condition of the foam dispersion method is that the system should have a foaming agent, or as salt (such as sodium carbonate, sodium carbonate, etc.) Sodium bicarbonate) and acid react to generate a large amount of gas in the polymerization system. The biggest bottleneck of this polymerization technology lies in the control of the reaction system. The liquid film in the foam gap generated instantaneously is used as the polymerization site, and the completed pores exist in the gel in the form of dispersion. There is no continuity. In addition, there is a complicated relationship between the removal of the heat of polymerization and the influence on the size of the foam. Therefore, the finished instant noodle gel block needs to remove the non-pore-forming area, and a large amount of solvent is required to remove impurities such as foaming agents. The follow-up treatment process is complex; (3) The key point of self-propagating wave polymerization technology is to use the reaction heat generated in the reaction area to trigger the unreacted area, and at the same time, the reaction heat in the newly reacted area promotes the solvent vaporization in the fully reacted gel to perform thermal synthesis. Pores, so the control of polymerization heat is the difficulty of the whole polymerization. The overheating of the reaction will lead to uneven pores. The polymerization reaction temperature is 80-110 ℃. When salt is used as the initiation system, the phenomenon of "polymerization quenching" will suddenly appear when the temperature is lower than 60 ° C. Therefore, the technology is only in the laboratory research stage at present, and it is difficult to quickly and effectively prepare porous water-absorbing polymers on a large scale; (4) low-temperature crystallization causes The pore method uses freezing and cooling to crystallize the solvent as a pore-forming agent, and leaves pores in situ after polymerization. This method is currently the only method that can prepare regular porous separation media. Ionic monomers are used as raw materials, tetramethylethylenediamine is used as an activator (catalyst) to initiate, and then the final catalytic acidification (cationization) modification is carried out to prepare finished products. The polymerization time is too long (more than 18h), so the preparation process is relatively long , the mechanical properties of the material (compressive strength The preparation of porous membranes has not been achieved on a large scale, and the finished product will be prepared by inactivating yeast and repeated cleaning. Undoubtedly, the subsequent processing is more complicated