Valorization of jeans waste into activated carbon through thiosulfate activation

Abstract

Textile waste is an increasing environmental problem that has not been tackled yet. This work explores the plausible valorization of denim fabric from jeans waste by the preparation of activated carbons through thermal decomposition and chemical activation. Although the denim fabric under pyrolysis led to a moderately porous char, the textural properties were considerably enhanced with chemical activation. Sodium thiosulfate was selected as the activating agent for this waste for the first time as a more environmentally friendly activating agent if compared to potassium alkali and carbonate. Moreover, thiosulfate overcomes some limitations of the other two, leading to a higher final yield, reduced water consumption in the washing step, high surface area (974 m2 g−1), and balanced presence of micro and mesopores. Chemically, the surface during thiosulfate activation was characterized by a large amount of oxygenated groups represented by carbonyl and quinone, as TPD and XPS characterization revealed. These properties enhanced the adsorption uptake of pharmaceuticals in water, such as sulfamethoxazole (312 mg g−1), acetaminophen (254 mg g−1), diclofenac (160 mg g−1), and antipyrine (213 mg g−1). In the treatment of heavy metal solutions, the activation resulted in the highest performance with Pb2+ (100 mg g−1) and was more limited with Cu2+, Ni2+, and Zn2+ when compared to the non-activated char.