α-Fe2O3、γ-Al2O3、SiO2混合体系的表面配位反应

α-Fe2O3、γ-Al2O3、SiO2混合体系的表面配位反应

刘嘉;张卫民;黄佩佩;樊佳妮;孙仁贵;孙中溪

【期刊名称】《物理化学学报》 【年(卷),期】2011(027)001

【摘要】We systematically studied the surface acid-base properites and complexation behavior of heavy metal ions in aqueous suspensions of α-Fe2O3, γ-Al2O3, SiO2 of mixed oxides and the α-Fe2O3/γ-Al2O3/SiO2 mixed systems using potentiometric titrations in combination with computer-based calculations using the constant capacitance model (CCM).The experimental and calculated results reveal that the surface chemical reactions in the mixed system are quite different from the sum of the individual single systems.A complicated mutual interaction exists among these mineral surfaces.The surface chemical reaction models and relevant equilibrium constants in the mixed system are: ≡XOH2+(=)≡XOH+H+(lgKa1=-4.23),≡XOH(=)≡XO-+H+(lgKa2=-8.41).The surface complexation model and related equilibrium constants for Cu2+, Pb2+, and Zn2+ in the mixed system can

be

described

by

following

reaction:

≡XOH+M2+(=)≡XOM++H+,with lgK of -2.20, -1.90, -3.20 for Cu2+, Pb2+, Zn2+, respectively.%运用自动电位滴定技术分别研究了纳米α-Fe2O3、γ-Al2O3、SiO2单一体系及三组分混合体系中氧化物表面的酸碱性质和对重金属离子Cu2+、Pb2+、Zn2+的吸附行为.依据表面配位理论恒电容模式(CCM),