Study on 4A molecular sieve loaded with Ce and γ-Fe2O3 for removal of Sb(Ⅲ)and Sb(Ⅴ)in water
In order to efficiently remove Sb(Ⅲ)and Sb(V)from water,a new type of Ce and Fe-loaded 4A molecular sieve adsorbent(4A@Ce-Fe)was synthesized by coprecipitation method.Ce and γ-Fe2O3 loading significantly improved the ad-sorption capacity of molecular sieve for antimony.When the Ce∶Fe mass ratio was 1∶3 and pH was 7.0,the maximum ad-sorption capacity of 4A@Ce-Fe for Sb(Ⅲ)and Sb(V)was 50.50 mg/g and 10.03 mg/g,respectively.The saturation magne-tization of 4A@Ce-Fe was 23.70 emu/g,which had good magnetic separation performance and was easy to separate from wa-ter.Langmuir isotherms could well fit the adsorption of Sb(Ⅲ)and Sb(V),and Langmuir and Freundlich isotherms could well fit the adsorption data of Sb(V).The adsorption kinetics study showed that the adsorption of Sb(Ⅲ)and Sb(V)was more in line with the pseudo-second-order kinetic model.The adsorbent had good adsorption effect on antimony at the initial pH=4.0～10.0,and Ce and Fe were hardly dissolved out.Cl-,SO42-and NO3-had little effect on the adsorption of Sb(Ⅲ)and Sb(V),and the presence of HCO3-and H2PO4-significantly reduced the adsorption capacity.XRD,SEM,BET,FT-IR,XPS and other test results showed that the possible adsorption mechanisms of Sb(Ⅲ)and Sb(V)on 4A@Ce-Fe included ion ex-change,surface complexation and oxidation-reduction reaction.The formation of M—O—Sb complex played a major role in Sb adsorption.
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