Karthikeyan KG, Elliott HA
Agricultural and Biological Engineering Department, The Pennsylvania State University, University Park, Pennsylvania, 16802
J Colloid Interface Sci. 1999 Dec 1;220(1):88-95. doi: 10.1006/jcis.1999.6507.
Surfacecomplexation models were used to simulate adsorption (ADS) and coprecipitation (CPT) of copper (Cu) by hydrous oxides of iron (HFO) and aluminum (HAO) over a range of pH and surface-loading conditions. The generalized two-layer model was satisfactory for two very different conditions: (1) low sorbate/sorbent ratios where metal-oxide interaction is adequately described as Cu(2+) coordination to surface functional groups and (2) under HFO-CPT conditions which result in extremely high adsorption site density (0.425 mol of sites/mol of Fe). As the sorbate/sorbent ratio is progressively increased, the models must account for metal hydrolysis and surface precipitate formation, and Cu interaction with both hydrous oxides could be fitted over a wide range of surface loadings using a comprehensive surface precipitation model. Similar mass law constants for sorption reactions were used for generalized two-layer and surface precipitation modeling, ADS and CPT conditions, and pH-edge and isotherm data. Corroborating sorption and spectroscopic evidence, modeling indicated that Cu precipitated on HAO, unlike HFO, has a markedly lower K(sp) than bulk precipitated Cu(OH)(2)(s). Results also suggest that enhanced Cu removal by CPT was not simply a manifestation of higher surface area. Copyright 1999 Academic Press.
采用表面络合模型，在一系列pH值和表面负载条件下，模拟了铁的水合氧化物（HFO）和铝的水合氧化物（HAO）对铜（Cu）的吸附（ADS）和共沉淀（CPT）过程。广义双层模型适用于两种截然不同的情况：（1）低吸附质/吸附剂比，此时金属氧化物相互作用可充分描述为Cu(2+)与表面官能团的配位；（2）在HFO-CPT条件下，该条件会导致极高的吸附位点密度（0.425摩尔位点/摩尔铁）。随着吸附质/吸附剂比逐渐增加，模型必须考虑金属水解和表面沉淀的形成，并且使用综合表面沉淀模型，可在广泛的表面负载范围内拟合Cu与两种水合氧化物的相互作用。吸附反应的类似质量作用常数用于广义双层和表面沉淀建模、ADS和CPT条件以及pH边界和等温线数据。支持性的吸附和光谱证据表明，与HFO不同，在HAO上沉淀的Cu的K(sp)明显低于块状沉淀的Cu(OH)₂(s)。结果还表明，CPT增强的Cu去除不仅仅是更高表面积的体现。版权所有1999年学术出版社。
