Modelling a multi-stage batch reactor for the immobilization of Fe(III) ions using humic acid and 2-mercaptobenzoxazole fabricated organo-clay

Abstract

Iron contamination in water resources has remained an unsolved issue globally for many years. This paper introduces a novel organo-clay adsorbent material resulted from the condensation reaction between humic acid, 2-mercaptobenzoxazole and Na-montmorillonite. The specific modification to the clay added the most active functional groups like –COOH, -NH2 and –SH, which imparts enhanced adsorption capacity for NaMMT-HA-MBO to bind Fe(III) ions. The capturing mechanism and the specific binding sites for the metal ions in the adsorbent was confirmed by XPS analysis. The adsorption performance of the material was evaluated and the theoretical optimization was carried out by response surface modelling. The NaMMT-HA-MBO showed a remarkable adsorption capacity of 77.0 mg/g, which outperformed many of the reported adsorbents in the literature. A multi-stage reactor was designed for calibrating the performance of the material during factorial operations. The adsorption of Fe(III) onto NaMMT-HA-MBO was spontaneous, complexation reaction mechanism with a PSO kinetics. The adsorbent material showcased an excellent regeneration capacity, ensures the reusability and stability of the material. Thus, the study unveils a functional organo-clay, which can be utilized as an effective adsorbent to remove Fe(III) ions from spiked and natural water systems.