Biologically produced sulfur as a novel adsorbent to remove Cd2+ from aqueous solutions

• Published in: Journal of hazardous materials Vol. 419; p. 126470
• Main Authors: Kim, Hyuck Soo, Jeong, Seok Soon, Lee, Jong Geon, Yoon, Jung-Hwan, Lee, Sang-Phil, Kim, Kwon-Rae, Kim, Sung Chul, Kirkham, M.B., Yang, Jae E.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 05.10.2021
• Subjects: Activated carbon; Adsorption isotherm; Adsorption mechanism; Biologically produced S; Cadmium; Biologically produced S; Cadmium; Activated carbon; Adsorption mechanism; Adsorption isotherm
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2021.126470

Biological desulfurization processes of landfill gas yield an enormous amount of biologically produced S (BPS) as a byproduct. Capability of BPS to remove Cd2+ from aqueous solutions was tested and its removal efficiency was compared to that of granular activated carbon (GAC). Kinetics of Cd2+ removal by BPS was a two-stage process with an initial rapid adsorption showing 45% of initial Cd2+ was removed within 5 min, followed by a slower adsorption. Cadmium adsorption onto the BPS fitted the Langmuir isotherm model and maximum adsorption capacity of the BPS (63.3 mg g−1) was 1.8 times higher than that of GAC (36.1 mg g−1). Thermodynamic parameters showed that Cd2+ adsorption by BPS was favorable and endothermic. Data from XPS proved the main adsorption mechanism to be complexation of Cd2+ with sulfides in the BPS. Results demonstrated that BPS can be recycled as a novel adsorbent for Cd2+ removal from wastewater. [Display omitted]