Kinetic, equlibrium, and thermodynamic evaluation of zinc, cobalt, and nickel ions removal from aqueous solution by modified biomass of asperigillus flavus

Abstract

Heavy metal ions of Zn (II), Co (II), and Ni (II) can be toxic to humans and environment, thus it must be removed from wastewaters before discharge to water bodies. In the present study, the biomass of Aspergillus flavus was modified by calcium chloride and used to removal of heavy metal ions (nickel, cobalt and zinc) from aqueous solutions. The effect of different parameters such as initial pH, adsorbent dosage, contact time and temperature on the efficiency of adsorption process was studied. Pseudo-second model compared to the pseudo-first model has greater ability to describe the kinetic data. According to the correlation coefficient (R²), Langmuir isotherm model was better described the isotherm behavior of the adsorption process. The maximum capacity for the adsorption of nickel, cobalt and zinc ions by the biomass of modified Aspergillus flavus was determined 32.258, 31.056 and 27.855 mg/g, respectively. ΔG°, ΔH°, and ΔS° parameters was showed that the biosorption of heavy metals by the adsorbent, is a possible, spontaneous and exothermic process.