Uptake of heavy metal Cd(II) from aqueous solutions using brown algae Sargassum myriocystum

Abstract

The uptake of brown marine algae, Sargassum myriocystum has been utilized for the exclusion of Cd(II) metal from wastewater. Various parameters such as solution pH, optimum temperature, biomass concentration, the contact time and agitation speed have been analyzed for the effective biosorption of Cd(II). Desorption studies of Cd(II) have been performed with various desorbent such as H3PO4, HNO3, HCL, H2SO4, NaOH, NaCl, and H2O among which 0.1M/L HCl is found to be the better desorbing agent. SEM-EDX and FTIR analyses were utilized for metal-algal interaction study. The thermodynamic parameters such as free energy change (ΔG°), enthalpy change (∆Hº) and entropy change (∆Sº) have been calculated through the Van’t Hoff plot. A positive value of 14.72 ∆S Jmol-1K-1, a negative value of free energy (ΔG°) and 42.21 kJ/mol of ∆H kJmol-1 at all the temperatures indicated that the process is feasible and spontaneous. Hence, S. myriocystum is an effective and prosperous cost-effective biosorbent approach for Cd(II) from various industrial wastes due to its fast sorption rate, high selectivity and great uptake capacity.