砷与无定形氧化铝的表面络合反应平衡常数计算

COMPUTATION OF SURFACE COMPLEXATION CONSTANTS FOR ARSENIC ADSORPTION ON AMORPHOUS Al-OXIDES

根据不同离子浓度、不同pH值的溶液中As在无定形氧化铝表面的吸附量,利用三种不同的表面络合模型计算As与无定形氧化铝表面络合反应的平衡常数,将计算得到的平衡常数模拟As(Ⅲ)无定形在氧化铝表面各个络合物种的吸附百分比与As(Ⅲ)的X光吸收光谱边缘结构分析结果进行定性比较,表明计算结果与分析结果较为吻合.从而验证了此次计算得到的平衡常数是准确的.

In this paper, we report calculated intrinsic equilibrium constants for several surface complexation reactions, which are computed by using three frequently used surface complexation models and experimental data from Arsenic adsorption on amorphous aluminum oxides at different solution ionic strength and pH. Using the computed intrinsic equilibrium constants, we, in turn, simulated the amount of adsorption of surface complexation species on the relevant solid surface. The results of simulation are consistent in comparison with that of As （Ⅲ ） XANES analysis, which shows the credibility of our calculation. The non-linear least square program, PEST, and the geochemical equilibrium speciation model, MINTEQA2, are used to simulate the arsenic adsorption on Al-Oxides.