Study On The Treatment Of Organic Compounds Mixed With Heavy Metal In Wastewater By Modified Chitosan

As a unique kind of natural organic polymer, the Chitosan and its derivatives is an important water treatment chemical because of its excellent performance of flocculation, adsorption and chelation. Of all the properties, adsorption of heavy metal ions and removal of organics have been hot points. But in most practical research, the experimental wastewater only contains single heavy metal or organics, which does not conform with the constituents of actual wastewater. In this paper, we prepared the AECTS and VCG through inverse suspension method and microwave radiation method and explored the modified chitosan’s adsorption performance of Cu2+, Zn2+ and organics under the coexistent conditions.With chitsoan as the raw matrial, a new type chitosan resin(AECTS) was prepared through inverse suspension crosslinking by formaldehyde and epichlorohydrin. The BET of AECTS is 1.762791m/g with more pores in surface, and it has similar crystal structure with CTS. The absorbtion of the AECTS is test in an 100ml mixture solution which contains Cu2+, Zn2+and organics of each 50mg/L in mixed.The results showed that when the AECTS is 150mg, pH=6, at room temperature, oscillation adsorption 5 hours, the adsorption performance is best of all. The adsorption capacity of AECTS to Cu2+, Zn2+and organics achieved 31.89mg/g% 18.21mg/g and 21.47mg/g, respectively. At the same time, the content of organics also affects the adsorption properties of adsorbent. When the concentration of organics is in the scope of 100 mg/L to 10000 mg/L, the adsorbent to the Zn2+ and organics have competition existing. However, the concentration of organics has no influence to the adsorption of Cu2+. When the3 concentration of organics is in the scope of 2500mg/L, the adsorption properties is relatively better, reaching 100%,59%,86% of Cu2+, Zn2+ and organics, respectively.Vanillin was grafted to chitosan under microwave radiation with the microwave power 300 w, heating temperature 70℃. The BET of VCG is 1.920447m2/g, its monomer is flaky, and has certain folds on the surface. The optimum adsorption conditions of VCG was determined:pHN6.0,200mgVCG, at room temperature, in the 100ml mixture solution, which containing Cu2+, Zn2+ and organics each of 50 mg/L, oscillation adsorption 5 hours, the adsorption capacity of VCG to Cu2+, Zn2+ and organics achieved 25mg/g、10.53mg/g and 21mg/g. In a 100ml mixture solution which contains Cu, Zn each 50mg/L and organics 2000 mg/L, VCG of 150mg/L worked best, the removal rate for Cu2+, Zn2+ and organics reached 100%,59% and 86%.The adsorption performance of AECTS and VCG are compared with CTS, the result showed that the adsorption performances of AECTS and VCG for the organics are obviously better than CTS, and the VCG’s adsorption ability is better than AECTS’. AECTS, VCG and CTS all had good adsorption to Cu2+, the adsorption capacity respectively were 32.16mg/g, 33.07mg/g and 33.33mg/g. The reault conformed to the BET analysis results. For the modified chitosan, the adsorption capacity of Zn2+ turns down, which may be concerned to the loss of adsorption sites of Zn2+.