Research Of The Adsorption Of H-acid By Using Series Of Amino Resins

H acid (1-amino-8-naphthol-3,6-disulfonic acid), as animportant kind of dye intermediates, has been widely used in textile, dyeing, pharmaceutical and other industries.Becasue of the problems such as high concentration, high chroma and high toxicity, it is difficult to purify such sort of wasteawaters. Once the hazardous material enters into the natural water, it will cause great harm to both the ecosystem and human life. This study aims to synthesize high effective and selective resins to adsorb H acid, and make some improvements on previous basis. The effects of skeleton structures, surface areas, pore size distributions and surface functional groups on the adsorption of H-acid are systematically investigated. The conclusions have been drawn as follows:(1) Two sulfonate acid groups in H-acid have strong hydrophilicity. The electrostatic attraction plays a major adsorption mechanism in the NDA-88, D-301 and the series of GMA resins. The hydrophobic interaction and π-π interaction has no obvious effect on the adsorption of H-caid on XAD-4 resin. The adsorptioncapacity depends onthe surface area, pore size, surface functional groups of resins. Higher specific surface area leads to higher adsorption capacity and higher initial adsorption rate.The resin pore size distribution affects the equilibrium time and adsorption capacity:Macroporous structureensures the continued diffusion of adsorbent in the resin internal in the whole adsorption process. According to the target adsorbent, the high selective resins have the right force to ensure high adsorption capacity. The pH of H-acid solutionaffectsthe morphology of the resin groups, and then hasa significant impact on the adsorption capacity. The coexisting anions makecompetitive adsorption with the sulfonic acid groupsandresults in different impacts on the H-acid adsorption on the resins.(2) Thesynthentic GMA resin may be influenced by the hydrophobic feature. The epoxy groupsmay be partially enclosed in the resin and the amine groups modification does not completely take place during the synthesis process. A kind of hydrophilic resins containing amine group by DMA instead of GMA are thus selected, and this sort of resins have fewer synthetic steps. The high selectivity resin with similar adsorption capacity aresynthsized by the adjustment of the dosage of monomer, crosslinker and porogen. The adsorption amount of resin is realted to surface area, pore size and functional groups. The increasing content of amine group can provide more binging sites that increase the adsorption amount of the resin. More proogen contribute the larger pore size, the shorter adsorption equilibrium time and the faster initial adsorption rate. And the more binging sites, larger adsorption capacity and adsorption rate relat to surface area.The optimal desorption condition was obtained by changing the content of each of desorbent material. DMA-220 has good practical research value and is thus selected in the following study about dynamic adsorption.(3) The adosprtion of H-acid onto resin isstudied by the dynamic adsorption. The impacts of flow speed and the solution concentration are studied by using self-prepared H-acid solution firstly. It is found that DMA-220 resin has better adsorption performance. The penetration volume was 210 bed volume (BV) when the initial concetration was 1000 mg/L. Then, real wastewater containing H-acid is applied in the dynamic adsorption study in order to investigate the synergistic removalperformance of COD, NO3- and SO42- by DMA-220 resin. The smaller penetration volume and adsorption capacity occurrs with the faster liquil flow rate. When the feed liquid flow rate was 0.5 BV/h, the penetration volume reached 8 BV. The best operating conditions for both adsorption and desorption are obtained.The experimental results show that DMA-220 resin has good dynamic adsorption stability in the adsorption column for repeated use. It has great potential to be used to in the treatment of actual wastewater.