Abstract

Lead is one of the trace metal ions and environmental pollutants that can be hazardous to humans and other organisms. The present study was conducted to evaluate the efficiency of Trichoderma fungus in biosorption of lead ions (Pb2+) from aqueous solutions. Hence, the optimal conditions for fungal growth were determined to investigate the effects of critical parameters affecting biosorption process, including pH, mixing rate, contact time, temperature and initial lead concentration. The findings of the experiments showed that the Trichoderma fungus could grow well within 24 h at pH and temperature equal to 5°C and 25°C, respectively. The highest growth rate in these conditions was 0.51 g/100 mL of broth medium. Maximum biosorption rate of Pb2+ (98.8) occurred at pH = 6 and initial concentration of 25 mg/L Pb2+. It was also found that mixing rate could have a positive effect on increasing the removal of Pb2+ by Trichoderma fungus. Evaluation of biosorption system behavior based on biosorption models determined that Langmuir model is the most appropriate one to explain the biosorption behavior. Under these conditions, the maximum biosorption capacity was obtained equal 25.05 mg Pb2+/g, which is very close to the value predicted by Langmuir model. © 2019 Desalination Publications. All rights reserved.