Characteristic pollutants treatment and recycling technology based on resin adsorption and separation

Source: B&R Working Committee

Applicating Company

Jiangsu NJU Environmental Technology Co., Ltd.

Technology Name

Technical principle

As a low energy consumption solid phase extraction separation technology, adsorption has been widely used in industry. Commonly used adsorbents are mainly activated carbon, modified cellulose, clay, silica gel, etc.. The most widely used activated carbon has high operating cost due to its poor mechanical strength, short service life and difficult regeneration, which affects its application in industry.

Macroporous adsorption resin is a synthetic polymer adsorbent with porous three-dimensional structure. It is a new kind of resin developed on the basis of the application of ion exchanger and other adsorbents. It mainly relies on van der Waals force between adsorbed molecules (adsorbates) and works based on physical adsorption on high specific surface. In practical application, it has strong adsorption capacity especially for some molecules with similar skeleton structure, such as aromatic cyclic compounds. Macroporous adsorption resin is insoluble in acid, alkali and organic solvents, with stable chemical properties, and can enrich, separate and recover organic substances from aqueous solution through intermolecular force. Compared with activated carbon, macroporous adsorption resin has the advantages of narrow pore distribution, good mechanical strength and easy desorption and regeneration.

The first-generation of commercial macroporous adsorption resin has some problems in practical application, such as unsatisfactory adsorption capacity, pore structure performance and mechanical strength. Therefore, by adjusting the physical structure (pore structure) and chemical structure (polarity) of the adsorption resin, our team synthesized the second-generation ultra-high cross-linked adsorption resin and the third-generation composite functional adsorption resin with high specific surface area, high adsorption capacity, high mechanical strength, different polarity and uniform pore size, so as to improve its adsorption selectivity, adsorption and desorption capacity, physicochemical stability and service life, and reduce its production cost and operation cost. It has been successfully applied to the treatment and recycling of various organic wastewater containing phenol, cresol, halogenated phenol, p-nitrophenol, p-aminophenol, 2,3-acid, phenylacetic acid, 2-naphthol, Tobias acid, o-phenylenediamine, fluoro(chloro)toluene, 1,4-dihydroxyanthraquinone, sorbic acid, etc..

In recent years, with the rapid development of nanotechnology, our team has developed the fourth-generation of nanocomposite adsorption materials based on the carrier netting confinement effect and Donnan effect, using macroporous resins with different surface properties as carrier and metal oxide / phosphate nanoparticles such as Fe (III), Zr (IV) and Mn (IV) as the target load. It has the advantages of large adsorption capacity, high selectivity, fast speed and excellent regeneration and reuse performance for pollutants such as Pb, Cr, Cu, Ni, As, P and F, thus has been successfully applied to raise emission standards for wastewater to reduce emissions in electronic electroplating, tanning, mining and other industries. Compared with conventional treatment technology, the comprehensive cost is reduced by about 30-50%.

Scope of application

(1) selective separation and enrichment of pollutants such as organic substance, heavy metals and salts in high concentration wastewater or waste liquid, and recovery of useful substances while effectively reducing pollution;
(2) deep purification of low and medium concentration degradation-resistant pollutants in water body, and meet the requirements of industry / region for water treatment standard upgrading and emission reduction.

Process flow and description

The engineering application devices of adsorption resin are mainly fixed bed and mobile bed developed on its basis. The main process flow of wastewater treatment by adsorption resin is shown in the figure. Firstly, carry out necessary pretreatment according to the inlet water quality, such as adjusting pH value, filtering, etc., the obtained solution is adsorbed by macroporous resin fixed bed, and the adsorbed effluent can be directly discharged up to the standard or enter the next level of treatment unit. When the resin reaches the adsorption penetration point, it needs to be desorbed. The low concentration desorption liquid can be used as the desorbing agent for the next batch. The high concentration desorption liquid can generally be reused in the production section, or directly recycled products for comprehensive utilization.

Promotion prospects

Resin adsorption is a technology to separate the target pollutants from the water by adjusting the structure of the resin as well as the functional groups and loads on the resin to form selective adsorption with the molecules of the characteristic pollutants in the water, and then desorb them from the solid phase through desorption agent, so as to achieve the dual effects of water pollution control and resource recovery. Compared with similar technologies, resin adsorption has obvious advantages in terms of advanced technology, economy and efficiency, and has broad development prospects and market potential.

Its main advantages are:

① Wide application range. This method can be applied to the concentration of wastewater from several to tens of thousands of mg/L, and the adsorption is not affected by the inorganic salts contained in the solution. It can also be applied in non-aqueous systems.

② Stable performance and long service life. The resin has good temperature resistance, acid and alkali resistance and organic solvent resistance, and has a long service life. Under normal circumstances, the service life of the adsorption resin is 8 ~ 10 years.

③ It is conducive to comprehensive utilization and the recovery of useful resources. Generally, organic intermediates, precious metals and other products in wastewater have high prices. This method can realize the recovery and utilization of most useful resources. It can not only obtain significant environmental and social benefits, but also produce certain economic benefits.

④ The operation cost is low in industrialization. Using this technology does not require special equipment, the technology is easy to master, and the energy and power consumption are low in operation.