Evaluation of ability of aspergillus terreus fungi in removal of cadmium from aquatic solutions: isotherm and kinetic studies

Cadmium is considered as one of the most hazardous heavy metals, a non-essential, non-beneficial and highly toxic element to people. In the current study, the ability of aspergillus terreus fungi biomass was surveyed in the removal of cadmium from aquatic solutions.
This cross-sectional study was carried out in 2015 using fungal biomass culture on a shake flask. The dead biomass of aspergillus terreus fungi was applied as an adsorbent for the treatment of aquatic solution under the conditions of cadmium concentrations: 20, 40, 60, 80, 100 and 120 mgþ/l, pH: 3, 5, 7 and 9, retention time: 15, 30, 45, 60, 90, and 120 min and adsorbent dose: 0.1, 0.2, 0.5, 1 and 2 g. The remained concentrations of cadmium after adsorption were determined by atomic absorption spectrophotometer.
Results indicated that under condition of retention time: 90 min, pH: 7, initial cadmium concentration: 20mgþ/l and adsorbent dose: 1g, the biomass had a removal efficiency of 94%. Moreover, Adsorption process fitted to Freundlich isotherm with R2=0.9463 and first order kinetic with R2=0.9935.
In current study, it was observed that the factors of pH, retention time, dose of aspergillus terreus fungi and initial cadmium concentration had a noticeable effect on the adsorption amount. with regard to the high adsorption capacity of the biomass in comparison to other adsorbents in the removal of cadmium, this biomass can be used as a good adsorbent in wastewater treatment.