Biosorption of chromium(VI) from aqueous solution and electroplating wastewater using fungal biomass

Abstract

Biosorption of Cr(VI) ions from aqueous solution as well as from electroplating effluent with dead fungal biomass sp. Aspergillus niger, Aspergillus sydoni and Penicillium janthinellum was investigated in the batch mode. The influence of pH of the solution, biosorbents dose, concentration of ions and contact time on biosorption capacity of Cr(VI) ions was studied. The optimum pH for biosorption of Cr(VI) ions was found to be 2.0. The removal of Cr(VI) was 91.03% with A. niger at biosorbent dose 0.6 g/50 mL, whereas, 87.95% and 86.61% with A. sydoni and P. janthinellum at biosorbent dose 0.8 g/50 mL but uptake capacity (mg/g) of Cr(VI) ions decreased with increased biosorbent dose. Initially percent removal of Cr(VI) ions from solution was increased with increase in concentration from 10 to 30 mg/L and maximum percent removal was observed at concentration 30 mg/L after that percent removal decreased. Whereas, uptake capacity was increased with increase in concentration of Cr(VI) ions from 10 to 60 mg/L. Uptake rate of Cr(VI) increased from 1.72 to 2.39 mg/g with A. niger, 1.22 to 1.76 mg/g with A. sydoni and 1.18 to 1.77 mg/g with P. janthinellum with increases time from 15 to 120 min. Removal of Cr(VI) from electroplating wastewater was observed less than from synthetic solution. Higher value of correlation coefficient (r2 > 0.90) indicates that adsorption data are best fitted in both Freundlich and Langmuir isotherms model. The high value of Freundlich constants Kf and n, i.e. 17.92 mg/g and 1.18 L/mg and Langmuir constants Q0 and b 17.61 mg/g and 0.0026 L/mg for A. niger indicate its better adsorption capacity than A. sydoni and P. janthinellum.