Preparation And Adsorption Properties For Cr(?) Of Modified Furfural Residue Adsorbent

Furfural residue is a kind of great potential adsorbent materials for the removel of Cr(VI) in the waste water because of its abundant source and low cost in biomass materials. The adsorbent prepared with furfural residue whose cellulose is utilizated may be a cheep and efficient adsorbent for the removel of Cr(VI),and improves the utilization value of furfural residue.Firstly, the cellulose of the furfural residue was epoxidized: the furfural residue preprocessed by NaOH was modified using the epichlorohydrin as etherification agent and pyridine as catalyst. The effects on the epoxy value of epoxidized furfural residue were discussed of the reaction conditions, and the optimum reaction conditions were obtained. The results showed that the epoxy value of epoxidized furfural residue reached 0.427mol/100 g under the conditions of the NaOH(10%) solution 2 mL, pyridine 5 mL, N,N-dimethyl formamide 16 mL, epichlorohydrin 8 mL, temperature 55 ? and reaction time 180 min. The characterization of the epoxidized furfural residue via FT-IR, XRD, SEM proved etherification reaction and the introduction of epoxy group.Secondly, the adsorption behavior of the epoxidized furfural residue for Cr(VI) was investigated. The results showed that the adsorption quantity of Cr(VI) reached 93.98 mg/g, higher than that of furfural residue,when the initial Cr(VI) concentration was 100 mg/L, the epoxidized furfural residue amount was 20 mg, pH=2, the adsorption temperature was 328 K and the adsorption time was 120 min.The used epoxidized furfural residue was regenerated by 1mol/L NaOH solution. The adsorption capacity of regenerated epoxidized furfural residue reached 74.14 mg/g after 5 desorptions.The adsorption behavior followed Langmuir isotherm much better. The adsorption kinetic analysis showed that the adsorption behavior followed the pseudo-second-order kinetic equation.Thirdly, the amino furfural residue was synthesized with epoxidized furfural residue and triethylene tetramine. The effects on the adsorption capacity of amino furfural residue for Cr(VI) were discussed of the reaction conditions. The optimum reaction conditions were obtained through orthogonal experiments: the epoxidized furfural residue 2.0 g, N,N-dimethyl formamide 12 mL, triethylene tetramine 6 mL, temperature 80 ? and reaction time 3.5 h. The characterization of the amino furfural residue via FT-IR, XRD, element analysis showed amino had connected to the cellulose molecules of the epoxidized furfural residue,and the crystal structure of the amino furfural residue changed little compared with the epoxidized furfural residue.Finally, the adsorption behavior of the amino furfural residue for Cr(VI) was investigated. The results showed that the adsorption quantity of Cr(VI) reached 177.26 mg/g when the initial Cr(VI) concentration was 80 mg/L, the amino furfural residue amount was 10 mg, pH=2, the adsorption temperature was 338 K and the adsorption time was 80 min.The used amino furfural residue was regenerated by 1mol/L NaOH solution.The adsorption capacity of regenerated amino furfural residue reached 153.31 mg/g after 5 desorptions,which showed that the amino furfural residue had excellent regeneration properties. The adsorption behavior followed Langmuir isotherm much better. The adsorption kinetic analysis found that the adsorption behavior followed the pseudo-second-order kinetic equation.