Biosorption performance and cell surface properties of a fungal-based sorbent in azo dye removal coupled with textile wastewater

Abstract

In this work, the biosorption ability of Sarocladium sp. dried biomass to remove Remazol Black dye has been studied. Optimum inoculum size and initial dye concentration were determined, and the salinity effect on the dye removal was evaluated. In the following, kinetic and isotherm of the adsorption were studied, and the adsorbent characteristics were determined using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy, zeta potential, and Brunauer–Emmett–Teller analysis. Based on the results, maximum and minimum dye removal was determined at 1000 and 200 mg L−1 of Remazol Black dye as 54.39 and 24.02 mg g−1, respectively. Among the various azo dyes including Reactive yellow 145, Reactive blue 222, Reactive red 43, Direct blue 21, and Acid blue 161, dye removal capability of 87.96–97.43% was obtained. The solution salinity showed positive effect on the biosorption process. The biomass pretreatment with calcium nitrate enhanced the removal capacity by 70.48% and the maximum reduction in dye removal (− 61%) was obtained when the fungal biomass was treated by sodium hydroxide. Biosorption kinetic follows the first-pseudo-order model, and the obtained data best fits both Langmuir and Freundlich isotherm models. The maximum adsorption capacity of dried biomass for dye removal was 58.48 mg g−1. Based on FTIR, zeta potential value and pretreatment results, Yoshida H-binding, dipole–dipole H-binding, π–π and n–π interactions were probably involved in the dye adsorption process. The results showed that biomass has a high potential for different dyes adsorption from real textile wastewater. The present study declares the high potential of Sarocladium sp. dried biomass as an effective and inexpensive biosorbent which can be used for bio-treatment of effluents with multi-dyes.