A study on the exchange additivity of zinc in solid mixtures in seawater——Ⅰ. Exchange additivity of mixtures

Exchange additivity of binary mixtures of hydrous metal oxides and clay minerals has been studied by investigating the relations of the zinc exchange-pH and the zinc partition coefficients to mixtures. The additive exchange equation is proposed to describe the exchange-pH relationship. The results suggest that zinc exchanges on the components in amorphous iron oxide/montmorrillonite, kaolinite/montmorrillonite, γ-Al00H/montmorrillonite, amorphous iron oxide/illite mixtures are additive. But the exchange of δ-MnO₂/montmorrillonite is much less than its additive exchange. It is also shown that in the case of additive exchange the exchange parameters (K_mix{→SOH}_Tmix) of the mixtures are equal in weight to the sum of those of each component of the solid mixtures.