Adsorption of Pb2+ in Aqueous Solutions by Biologically Produced Sulfur as a Novel Adsorbent

Abstract

In the process of biological desulfurization of gases from landfills, huge amounts of biologically producedSulfur (BPS) were produced as by-products. A study was conducted to find out the possibility of using it as anadsorbent for Pb2+. BPS was subjected to an adsorption test in an aqueous solution in the presence of Pb2+ andcompared with the removal efficiency of granular activated carbon (GAC), which is mainly used as anadsorbent for heavy metal. As a result of the Pb2+ removal experiment using BPS, it was a two-step process inwhich 54.5% of the initial Pb2+ was removed within 5 minutes by fast initial adsorption followed by slowadsorption. As a result of the isotherm adsorption experiment, the Pb2+ adsorption to BPS was fitted theLangmuir isotherm model, and the maximum adsorption capacity of BPS (175.4 mg g-1) was about 3 timeshigher than that of GAC (67.11 mg g-1). The data from XPS demonstrated that the main adsorption mechanismwas the complexation of Pb2+ with the sulfide in the BPS. Therefore, it was confirmed that BPS has sufficientvalue to be recycled as a new adsorbent for Pb2+ removal in wastewater.