Karthikeyan KG, Elliott HA, Chorover J
Agricultural and Biological Engineering Department, The Pennsylvania State University, University Park, Pennsylvania, 16802
J Colloid Interface Sci. 1999 Jan 1;209(1):72-78. doi: 10.1006/jcis.1998.5893.
Isotherms were developed at pH 6.9 for adsorption (ADS) and coprecipitation (CPT) of Cu by hydrous oxides of Fe (HFO) and Al (HAO) to study the role of sorbate/sorbent ratio in metal cation removal. For low sorbate/sorbent conditions, HFO had a higher Cu retention capacity than HAO regardless of contact methodology. For either oxide, CPT was consistently more effective than ADS in removing Cu from solution. At high sorbate/sorbent ratios, surface precipitation dominates and the oxide's net cation retention capacity depends on the nature and solubility of the precipitate formed at the oxide-water interface. X-ray diffraction patterns and isotherms of HAO for both ADS and CPT suggest formation of a solid solution [e.g., CuAl2O4(s)] with dramatically lower solubility than Cu(OH)2(s) precipitated in bulk solution. In contrast, Cu precipitated on the HFO surface exhibited a solubility comparable to the bulk precipitated Cu(OH)2(s). Therefore, at high sorbate/sorbent ratios, HAO has a higher Cu "apparent" sorption capacity than HFO. The relative utility of these oxides as metal scavengers thus depends markedly on sorbate/sorbent conditions. Copyright 1999 Academic Press.
在pH值为6.9的条件下，通过铁的水合氧化物（HFO）和铝的水合氧化物（HAO）对铜进行吸附（ADS）和共沉淀（CPT），绘制等温线，以研究吸附质/吸附剂比例在金属阳离子去除中的作用。在低吸附质/吸附剂条件下，无论采用何种接触方法，HFO的铜保留能力都高于HAO。对于任何一种氧化物，CPT在从溶液中去除铜方面始终比ADS更有效。在高吸附质/吸附剂比例下，表面沉淀起主导作用，氧化物的净阳离子保留能力取决于在氧化物 - 水界面形成的沉淀的性质和溶解度。HAO在ADS和CPT条件下的X射线衍射图谱和等温线表明形成了一种固溶体[例如，CuAl2O4(s)]，其溶解度比在本体溶液中沉淀的Cu(OH)2(s)低得多。相比之下，在HFO表面沉淀的铜的溶解度与本体沉淀的Cu(OH)2(s)相当。因此，在高吸附质/吸附剂比例下，HAO的铜“表观”吸附能力高于HFO。因此，这些氧化物作为金属清除剂的相对效用明显取决于吸附质/吸附剂条件。版权所有1999年学术出版社。
