Ion exchange resins have been widely used in the field of water treatment. Application of ion exchange resin in the treatment of mercury wastewater, copper-containing wastewater, organic wastewater, etc. The wastewater treatment ion exchange resin method of the present invention has the advantages of deep purification, high treatment efficiency, and comprehensive recovery of multiple metals, and will surely be more in-depth application in the field of water treatment.
"Ion exchange resin" is a functional polymer material containing ion exchange groups in the cross-linked polymer structure. Ion exchange resin is insoluble in acids, alkali solutions and various organic solvents, and is a porous solid polymer substance that neither dissolves nor melts in structure.
1. Research on the application of ion exchange resin technology in wastewater treatment
1.1. Treatment of mercury-containing wastewater
(1) Resin exchange method is used to remove mercury as the secondary treatment system of the chemical method, which can ensure that it meets the emission standards, and can achieve a closed cycle, continuous and stable operation, and the discharged wastewater can be reused as cooling water;
(2) Improved production capacity, reduced unit product cost, and saved management costs;
(3) The resin exchange method can also decolorize the wastewater, and the treated water is clear and transparent. The expired resin is no longer recycled, and mercury is recycled as mercury waste residue, which prevents secondary pollution.
1.2. Treatment of copper-containing wastewater
Choose a variety of macroporous strong acid ion exchange resins to absorb and concentrate copper ions in wastewater containing organic substances. By measuring the removal rate of various resins on copper ions, the effect of different copper ion concentrations and solution pH on the removal rate, and the comparison of the regeneration performance of each resin, it is shown that the "bright" resin, "strong acid No. 1" resin and PK208 resin have The most outstanding performance, the effect is obviously better than other resins; its ion exchange performance is stable, and it has good reproducibility. At the same time, the adsorption and removal capacity of Cu2+ can fully meet the requirements, and the concentration of Cu2+ in the purified water is less than 0.1mg/L, which can be used for the purification of copper-containing wastewater.
1.3. Treatment of molybdenum-containing wastewater
"The exchange rate of low-valent molybdic acid polymer and resin is much slower than that of molybdate. The reason is that low-valent molybdic acid polymer is mainly exchanged with resin by hexapolymer, while molybdate is adsorbed by tetrapolymer. And the pore size of the gel-type resin is very small, so the diffusion resistance of the low-valent molybdic acid polymer in the resin is relatively large, resulting in a low exchange rate. Although the adsorption speed of low-valent molybdate polymer on the resin is slower, the molybdenum salt occupies the exchange position on the resin and bonds with the resin more firmly. It is more difficult to desorb than the resin with molybdate adsorbed. Only after oxidation with an oxidant (such as 1mol/LHNO3) can it be desorbed relatively quickly. Because under acidic conditions, Mo(VI) is easily reduced to low-priced molybdenum by reducing agents, and low-priced molybdic acid polymers are not only difficult to exchange with the resin, but elution is also troublesome. Therefore, the reducing agent in the molybdenum-containing wastewater to be treated should be removed first, and its pH value should preferably be adjusted to greater than 7.
Ion exchange resin method is a more effective treatment method for wastewater, and there are many experiences to learn from. Just as a useful treatment technology always has its scope of application, the ion exchange method also has shortcomings, such as high one-time investment, strict operation requirements and management, and some also have regeneration problems, resin poisoning and aging problems. However, some problems have been solved, and improvement can be done. Giving full play to the recovery function of the ion exchange method can not only protect the environment, but also has a great advantage in terms of economic benefits. Therefore, ion exchange resins have a broad development space in the field of water treatment and should be paid attention to.