Copper and nickel ion removal from synthesized process water using BSA-coated bubbles

Abstract

Biosorption of a ternary system containing copper, nickel and calcium ions was conducted to examine the ability of air-filled emulsions (AFE) to remove heavy metal ions from a synthetic process water. AFE is a novel colloidal material containing fine air bubbles encapsulated by a thin film of cysteine-rich protein. AFE introduces a high interfacial surface area between metal ions and extractant. Impact of different experimental conditions such as calcium ion concentration, AFE dosage and final solution pH on metal ion uptake was explored. Calcium ions exhibited an adverse effect on copper removal, which reduced by 70% due to both higher affinities of active binding sites for calcium ion compared to that of copper and nickel ions and bridging flocculation of microbubbles occurred in the solution. The results acquired from potentiometric titration showed the presence of three functional groups on the surface of bubbles (carboxylic, thiol and amine groups), the carboxylic group being the most abundant.