An innovative strategy for synchronous treatment of combined heavy metal and organic pollutants through polysaccharide gel encapsulating S2−

In many industrial fields, treatment of composite contaminations involving inorganic heavy metal ions and organic pollutants simultaneously remains a tremendous challenge. In this paper, an innovative strategy based on the gelation process of Sodium Alginate (SA) was proposed for synchronous treatment of composite pollutants. Through a pre-gelation step, SA gel balls encapsulated with S 2− (SA/S 2− gel) were formed and immersed into polluted solutions containing Pb 2+ /Cd 2+ and Cd 2+ /dye. The removal efficiency of Pb 2+ /Cd 2+ by SA/S 2− gel were both increased compared with pure SA gel. The adsorbed Pb 2+ /Cd 2+ was in-situ transformed into PbS/CdS quantum dots (QDs) possessing photo-catalytic activity, which induced the degradation of dyes under UV irradiation. In this respect, the proposed SA/S 2− system might provide a high-performance and energy-saving way for comprehensive treatment of inorganic heavy metal and organic industrial pollutants.