Congo red removal from aqueous solution by a consortium of <i>Aspergillus</i> sp. immobilized on activated carbon in a packed bed column: modelling of the breakthrough curves

Abstract

In the present study, the potential of fungal cells (Aspergillus tubingensis KJ650338 and Aspergillus pseudonomius MH279416) immobilized on activated carbon (AC) derived from rice husks for biosorption of dye in a continuous flow-packed bed column, was assessed. The effects of different process parameters including inlet Congo red concentration, feed flow rate, biosorbent dose, and internal column diameter on the breakthrough curves of the fixed bed sorption system were evaluated for the different treatment groups. Non-linear forms of well-established models such as Yoon-Nelson, modified dose-response, and Thomas were used to describe the data obtained from the breakthrough curves under different conditions. The results suggested that high biosorbent dose (4 g), low column diameter (1.5 cm), low initial Congo red concentration (50 mg/ml), and reduced flow rate (0.5 ml/min) were the best conditions for biosorption of Congo red from solution. The modified dose-response model had the best correlation with the obtained data (R2 = 0.920–0.995) compared with Thomas model (R2 = 0.645–0.982) and Yoon-Nelson (R2 = 0.731–0.982). The maximum absorptive capacity (66.15 mg/g) was predicted at using modified dose-response (R2=0.987). These findings show that the dead biomasses of Aspergillus pseudonomius and Aspergillus tubingensis immobilized on powdered AC derived from rice husk could be cost-effective biosorbent for Congo red removal from aqueous solution in a fixed-bed column system.