REMOVAL OF ACRIDINE RED DYE FROM AQUEOUS SOLUTION USING PHYSICOCHEMICALLY ACTIVATED HYDROCHAR OF SPENT MUSHROOM SUBSTRATE

Abstract

Sustainable solutions for environmental restoration are crucial due to the increasing release of toxic substances in the ecosystem. The adsorption capacity to remove acridine red from an aqueous solution was investigated using the hydrochar of the spent mushroom substrate, which was obtained by the process of hydrothermal carbonization at a moderate temperature. To improve the adsorption capacity, hydrochar was subjected to chemical activation with 20% CaCl2·5H20, and then physical activation of the pyrolysis was performed at 500 °C, whereby Ca-pyro-hydrochar (Ca-PHC) was synthesized. The adsorption performance of Ca-PHC was analyzed at 22 °C and the obtained results were applied to four different isotherm models: Langmuire, Freundlich, Temkin, and Dubinin–Radushkevich. The calculated data suggest that the Langmire and Freundlich model best describes the investigated removal process and that the maximum sorption capacity of acridine red was 31.8 mg g−1. Based on the SEM analysis, the appearance of microspheres was observed, which was caused by the degradation of cellulose during the pyrolysis of the spent mushroom substrate. The number of pores of the examined material increased, which contributed to its increase in adsorption capacity. These findings indicate that the used biosorbent is effective for the remediation of textile wastewater.