Adsorption behavior of reactive Red 24 and methylene blue onto Brewer’s spent grain: characterization, kinetics, and isotherms modeling

Abstract

ABSTRACT Dyestuff wastes, made by the textile, paper, and dye industries, stay in the waste environment because they resist chemical and biological degradation. Treating industrial effluent to remove pollutants and lessen their effects before releasing them into the environment is crucial. Malt bagasse (BSG; Brewer’s Spent Grain) from a local brewery was used as an adsorbent for the textile industry dyes Methylene Blue (MB) and Reactive Red 24 (RR24). The adsorption of MB and RR24 was conducted at pH 7.00 and 1.50, respectively. While the temperature change had little effect on the MB adsorption process and capacity, the RR24 adsorption rate was increased without affecting the capacity. Both dyes’ adsorption mechanisms better fit the Langmuir isotherm and pseudo-second-order kinetic models. The maximum adsorption capacity was 80.31 mg/g for MB and 100.52 mg/g for RR24. Experiments using simulated wastewater indicated that the matrix did not significantly affect the efficiency with which RR24 and MB were removed. The findings suggest that BSG is a promising alternative adsorbent that is inexpensive, accessible, and simple to obtain.