Pb (II) Recovery by Trout Bones: Adsorption, Desorption and Kinetic Study

Abstract

Heavy metal removal from the water was studied by using fish bones produced in the trout farm of Atatürk University Faculty of Fisheries. Fish bones used as adsorbent were obtained from rainbow trout (Oncorhynchus mykiss). Trout bone was used in its natural form. According to the experimental results that maximum Pb (II) adsorption capacity of rainbow trout bones was 188.16 mg/g. The Langmuir, Freundlich, and Temkin isotherm models were applied to describe the adsorption of Pb (II) on trout bones. Langmuir and Freundlich isotherm models were found more favourable than Temkin with the correlation coefficients of 0.999, 0.999, and 0.857, respectively. Controllable factors used in this study were solution pH, temperature, adsorbent dosage, mixing speed, and initial Pb (II) concentration. The optimum working parameter values for Pb (II) adsorption using trout bones were found to be 5.5, 30 ºC, 3 g/L, 200 rpm, and 10 mg/L for pH, temperature, adsorbent concentration, stirring speed, and initial Pb (II) concentration, respectively. The adsorption kinetics of Pb adsorption by trout bones was modelled using the pseudo-first order and the pseudo-second order kinetics equations. The results indicate that, pseudo-second-order kinetic model gives more favourable results (R2mean = 0.997) than pseudo-first-order (R2mean = 0.971). Fish bones were characterized by some instrumental analyses such as SEM, EDS, FTIR, and zeta potential measurements. In the regeneration phase of the study, maximum desorption efficiency was 95.86% at pH 1.5.