Adsorption Isotherm, Kinetic and Thermodynamic Modelling of Bacillus subtilis ATCC13952 Mediated Adsorption of Arsenic in Groundwaters of Selected Gold Mining Communities in the Wassa West Municipality of the Western Region of Ghana

Abstract

In this study the potential of the live fungus Aspergillus niger (A. niger) to remove 2-chlorophenol (2-CPh) and 4-chlorophenol (4-CPh) was evaluated. The biosorption properties are affected by the treatment conditions, such as initial pH, contact time, initial chlorophenol concentration, biomass concentration, and temperature. The optimal pH value for 2-CPh and 4-CPh biosorption by the live A. niger was found to be a natural pH of 5.1. The biosorption of 2-CPh reached equilibrium in 48 h, whereas, the equilibrium for 4-CPh was reached in 96 h. From the sorption studies it was observed that the uptake of 2-CPh was higher than 4-CPh. The sorption isotherms of 2-chlorophenol and 4-chlorophenol were modeled according to the Langmuir and Freundlich equations. The equilibrium data fit well with the Langmuir isotherm model for 2-CPh and 4-CPh. The rates of biosorption were found to obey the rules of the intra-particle diffusion model with good correlation for especially 4-CPh. When the initial 2-CPh concentration was increased from 50 mg/L to 690 mg/L, the biosorption capacity of A. niger increased from 4.81 mg/g to 38.80 mg/g. However, the maximum 4-CPh biosorption capacity was obtained as 12.26 mg/g for 260.8 mg/L initial 4- CPh concentrations at pH 5.1 and 28°C. This research showed that fungal biosorption has a potential to be used in the removal of 2-CPh and 4-CPh from wastewaters.