Efficiency evaluation of AspergillusTerreus in the removal of chromium (VI) from aqueous solutions:Isotherm and kinetic studies

Chromium (VI) is one of the very toxic heavy metals and is known as a carcinogenic, mutagenic and teratogenic agent. In this study, the ability of dead Aspergillus Terreus fungus biomass in the removal of chromium (VI) from aqueous solutions was investigated.
The suspension of AspergillusTerreus was cultivated in Potato Dextrose Agar and Potato Dextrose Broth mediums. The biomass was then boiled in 0.5 N NaOH solution. The ability of obtained biomass to absorb Chromium (VI) was studied with respect to various variables including time (15 to 120 min), pH (3 to 11), chromium (VI) concentration (20 to 120 mg/L) and absorbent dosage (0.1 to 0.8 g). Chromium concentration was determined using an atomic absorption of. All ethical issues and citations were taken into consideration in conducting the study.
Results showed that the maximum removal of chromium (89%) was obtained at contact time 90 min, pH=7, chromium concentration 20 mg/L and adsorbent dosage 0.6 g. The adsorption isotherm was best fitted by Freundlich with a high correlation coefficient (R2=0.952). Furthermore, the adsorption kinetics fitted well to the pseudo-first-order model with a correlation coefficient of 0.9775.
The results of present study indicated that the studied variables have an incredible effect on sorption efficiency, as in the optimum condition, the biomass of AspergillusTerreus obtained an acceptable efficiency and adoration capacity compared to other adsorbents. So, this compound can be introduced as a practical natural adsorbent for chromium removal and also other heavy metals form aqueous solutions.