Preparation of Thiohydroxy Modified Magnetic Mesoporous Silica from Rice Husk and its Removal Properties for Cd （II）

Abstract:

In this paper，magnetic mesoporous silica （MMS） was prepared by using rice husk ash as the silica source and Fe3O4 as the magnetic material，and then MMS was modified by TMMPS as the silane coupling agents. The effects of agitation time，reaction temperature and the amount of ammonia on the surface thiohydroxy concentration were investigated during the preparation process and the effect of surface thiohydroxy concentration on the adsorption capacity on Cd2+ was investigated during the adsorption process. At last，the end product named thiohydroxy modified magnetic mesoporous silica （TMMS） and MMS was characterized and the adsorption effect of MMS and TMMS for Cd2+ was compared by adsorption isotherm. It was found that when the reaction condition was 8 h at 80 ℃ and the amount of ammonia was 750 ?滋L，the surface thiohydroxy concentration of TMMS was 0.131 mmol/g. The adsorption effect was in direct proportion to the surface thiohydroxy concentration. The BET surface area of MMS and TMMS was 581.769 m2/g and 405.665 m2/g respectively. The isotherm had a good correlation with Langmuir isotherm model rather than Freundlich isotherm model，which suggesting that the adsorption was monolayer adsorption. When the reaction temperature during the adsorption process was 30 ℃，the saturated adsorption capacity of TMMS was 33.33 mg/g，which was bigger than the value of MMS. Therefore，the purpose of effective removal of Cd2+ in wastewater can be achieved by modification.