| Aromatic sulfonic acid compounds are widely used as a kind of chemical products, in the process of their production and use will produce large amounts of organic wastewaters. The environmental pollution is very serious because this kind of wastewaters with high yield and concentration were difficult to treat. The treatment and recovery of these wastewaters had attracted widespread attention.In this study, four weak base anion exchange resins with different pore structure, which named QL-6-1, QL-6-2, QL-15, QL-30, were synthetised by changing the degree of crosslinking or porogen content. Through the test of static adsorption of 2-naphthalene sulfonic acid and alizarin green on QL-6-1, QL-6-2, QL-15, QL-30 and commercialized resin D301, the adsorption behavior of were studied. Effects of pH, temperature, concentration of Na2SO4 and other factors on adsorption behavior were investigated. Through the dynamics experimental, the effects of pore structure on the adsorption rate were studied. Dynamic competitive adsorption and desorption of 2-naphthalene sulfonic acid-alizarin green composite system on resins were investigated.The results showed that the best pH range of adsorption of 2-naphthalene and alizarin green was 1-2. Freundlich model could fit the adsorption behavior of 2-naphthalene sulfonic acid on resins, and the adsorption capacities were as follows:QL-6-1>QL-6-2>D301>QL-15>QL-30. Langmuir model could fit the adsorption behavior of alizarin green on resins, and the adsorption capacities of alizarin green were as follows:D301>QL-15>QL-30>QL-6-1>QL-6-2. Adsorption of 2-naphthalene and alizarin green was an exothermic reaction, and the adsorption process could be carried out spontaneously. The existence of a large amount of Na2SO4 would inhibit the adsorption of 2-naphthalenesulfonic acid on resins. Compared to D301, QL-6-1, QL-15 and QL-30 had superior characteristic of salt resistance. Kinetic studies showed that the data of 2-naphthalene sulfonic acid and alizarin green on the four resins fitted well in pseudo-second-order, the rate constant k2 of resins were as follows:QL-30>QL-15>QL-6-2> QL-6-1, and particle diffusion controlled adsorption process. QL-6-1 and QL-30 were selected as the adsorbents for dynamic adsorption experiments, in the composite system of 2-naphthalenesulfonic acid and alizarin green, QL-30 had higher selectivity for Alizarin green which has larger molecular size. QL-6-1 and QL-30 can realize effective desorption of 2-naphthalene sulfonic acid and alizarin green. Desorption and regeneration of resin and recovery of contaminants could be well carried step by step. |
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