Removal of malachite green by adsorption and precipitation using aminopropyl functionalized magnesium phyllosilicate

Abstract

We report a method for the removal of malachite green (MG) by adsorption and precipitation using nano-sized aminopropyl functionalized magnesium phyllosilicate (AMP) clay. MG, which is used in aquaculture and fisheries, is a carcinogenic and mutagenic compound. In response to these health risks, many efforts have been focused on adsorption of MG onto various adsorbents, which is a versatile and widely used technique for removing MG from water. Herein, we describe the adsorption and precipitation of MG using AMP clay, as well as the alkaline fading phenomenon of MG. In this study, prepared AMP clay and the precipitate product after the reaction of MG–AMP clay mixture were characterized. In addition, adsorption isotherms and kinetics, as well as thermodynamic studies are presented. Based on the results, we suggest a macro- and microscopic removal mechanism for the adsorption and precipitation of MG using AMP clay. An AMP clay dosage of 0.1 mg mL −1 exhibited a maximum removal capacity of 334.80 mg g −1 and 81.72% MG removal efficiency. With further increases of the AMP clay dosage, removal capacity by AMP clay gradually decreased; at dosage above 0.2 mg mL −1 of AMP clay, the removal efficiency reached 100%.