Co-biosorption potential of acacia nilotica bark in removing ni and aminoazobenzene from contaminated wastewater

In this biosorption study, the potential of Acacia nilotica bark in simultaneous removal of Ni and ami-noazobenzene was investigated. For this purpose, the impact of different experimental conditions on the co-biosorption potential of Acacia nilotica bark was studied. In result, the maximum biosorption of Ni and dye was in the acidic range pH, that is, 6 and 4, with sorbent dosage of 1 and 0.8 g after 40 min of the experiment when both were at 4 ppm, respectively. In case of adsorption isotherms, both mono-and multi-layer adsorption occurred simultaneously in the case of Ni as clear from the R² values of isotherms (R² for Langmuir = 0.999) and (R² for Freundlich = 0.941). In case of dye, uniform monolayer adsorption was predominant (R² for Langmuir = 0.980) as compared to the multi-layered adsorption. The maximum amount of monolayer adsorption of Ni and dye onto the biosorbent was 0.60 and 0.348 mg g^–1, respectively. From the kinetics model, chemisorption was predominant in the case of both Ni and dye adsorption on biosorbent. In conclusion, the bark of Acacia nilotica has great potential for Ni and dye removal from co-contaminated wastewater.