Biochars derived from textile industry solid wastes and their potential applications

Abstract The expansion of the textile and fashion industries has intensified natural resource consumption and environmental pollution. Consequently, countries with significant textile sectors, such as Türkiye, face substantial challenges in managing textile waste. This study aimed to utilize solid wastes from a textile finishing factory for biochar production. Cotton and cotton/polyester fabric wastes, textile wastewater sludge, and mixed waste (the mixture of all three waste streams) were converted into biochar at different pyrolysis temperatures (300–500 °C). The use of the resulting biochars as solid energy feedstocks, soil improvers, and adsorbents was investigated. The energy and agronomic properties of biochars were analyzed. A van Krevelen diagram indicated that the fabric waste‐based biochars obtained at 300 °C possessed a lignite‐like structure but this was transformed into a bituminous coal‐like structure at higher pyrolysis temperatures. Biochars derived from mixed waste had similar H/C and O/C ratios to bituminous coal. The stable carbon, pH, conductivity, water holding, and cation exchange capacity of the biochars, which are related to their potential agricultural applications, were analyzed. The results showed that cotton fabric waste and mixed waste‐based biochars have the potential to be used as soil amendments. Biochars produced at 500 °C were physically activated with CO₂ and steam to generate activated carbon. This process resulted in highly microporous activated carbons with surface areas reaching up to 795 m 2 g –1 . CO 2 ‐assisted activated carbon was derived from the fabric waste. Mixed waste‐based biochars exhibited promising performance in reactive dye adsorption. Overall, this study showed that the biochars produced from textile industry solid wastes can be used as energy feedstocks, soil improvers, or adsorbents. These solutions are effective for the textile industry and align with circular economy and sustainability principles.