Sorption kinetics of heavy metals from aqueous solution using Spirogyra sp.: a microcosm study

Understanding the mechanisms by which algae communities respond to disturbances in the loticaquatic environment that is polluted by heavy metals is important, considering that algae is a bioticcomponent of waters that acts as a producer in the aquatic food chain which has the potential to bio-magnify.This study examines the influence of time, biomass weight, heavy metal concentration, sorption capacity,and efficient removal on epilithic periphyton as a bio-accumulator of Cr, Pb, and Ni. The experiment wasconducted on a laboratory scale using a canal system with a length and width of 1.2 and 1.0 meters,respectively. The canal system contains 132 L of water, has a 1.2 msubstrate and periphyton area, a depthof 0.09 – 0.10 m, and a current flow rate of 0.04 – 0.06 m/s. The dissolved Cr2initial concentration in themedium was 1.64 mg/L, Pb6+concentrations were 1.4 mg/L, and the adsorption process was studiedfor 24 hours. Based on microscope observations and functional group interpretation utilizing infrared spectra(FTIR), the periphyton community is dominated by Spirogyra sp., which has hydroxyl (O-H), carboxyl (C-H),and carbonyl (C-C and C=O) functional groups with the ability to binding heavy metals. The remainingquantities of Cr, Pb, and Ni2+and Ni2+in water were 0.43 mg/L (removal 69.29%), 0.05 mg/L (96.43% removal), and0.03 mg/L (97.86% removal). Periphyton has a maximal sorption capacity of 1.019 mg Cr/g, 1.97 mg Pb/g,and 1.92 mg Ni/g. The sorption kinetics of Cr, Pb, and Ni follow a pseudo-second-order model with k2 = 1.686x 10of 0.965 forCr and 0.971 for Pb and 0.972 for Ni. Periphyton can potentially play a role as a bio-accumulator in lotichabitats, adsorbing Cr, Pb, and Ni-2g/mg.min for Cr, 4.516 x 10-3g/mg.min for Pb, and 2.259 x 10-2g/mg.min for Ni, with R2ions, according to this study.