Cu2+ and Ca2+ adsorption to goethite in the presence of fulvic acids

摘要: Abstract The interaction between copper ions (Cu2+), Strichen fulvic acid (FA), and goethite has been studied with batch experiments in the pH range of 3–11. Similar systems Ca2+ have previously are used here for comparison. Depending on Cu2+ loading, binding Cu to solid phase is enhanced or reduced by presence FA. complexation ternary can be mostly described reasonably well assumption linear additivity neglecting FA at surface, except low loading high loading. A surface model, Ligand Charge Distribution (LCD) describe mixture By considering both type (goethite–Cu–FA) B (goethite–FA–Cu) complexes, LCD model descriptions adsorption general good agreement data. Results show that complex cation bridging (type A) dominating species pH, whereas bound only more important Complexation ligands adsorbed complexes) not Cu. In interface, attribute charge than 1-plane, where a large fraction negative resides, which explains stronger enhancement compared Cu2+.