Immobilized Mucor plumbeus on sepiolite support: A potential decolorization agent suitable for batch and continuous mode water treatment

Abstract This study was focused on the design of a new and effective decolorization agent by immobilization of Mucor plumbeus cells on the sepiolite matrix (MPSP). The passive immobilization method was used to attach the microbial cells to sepiolite. Methyl violet (MV) decolorization performance of this immobilized material was examined through batch and dynamic flow sorption studies. Biosorption of MV onto MPSP was characterized by using IR, SEM, EDX, and zeta potential analysis. MPSP achieved 89.60% decolorization performance under the optimum batch conditions. Langmuir isotherm model was found as the best-fitted model for the equilibrium data of MV biosorption. The highest monolayer sorption capacity of MPSP was 187.76 mg g−1. Sorption kinetics followed the pseudo-second-order model and the highest rate constant was recorded as 2.56 × 10−4 g mg−1 min−1 at 45 °C. Gibbs free energy (ΔG°) changed from −24.269 to −26.257 kJ mol−1 when the temperature was increased from 15 to 45 °C. Decolorization was identified as exothermic in nature (ΔH° = −5.176 kJ mol−1) and sorption reaction was accompanied by an increase in entropy (ΔS° = 0.066 kJ K−1 mol−1). IR analysis indicated that –OH and –C O groups played a role in the sorption. Fixed bed MPSP column showed almost 100% decolorization yield, good regeneration, and reusability potential. Although there are several studies conducted on the preparation of immobilized sorbent materials, this is the first study of the combined action of sepiolite and M.plumbeus cells for sorption purposes.