Environmentally friendly, hydrothermal treatment of mixed fabric wastes containing polyester, cotton, and wool fibers: Application for HMF production

Herein, a mild and efficient method for the production of 5′-hydroxymethylfurfural (HMF) from polyester/cotton mixed fiber waste is reported for the first time. This is expected to be the first step in a continuous flow process for the recovery of HMF from cotton-containing fabric wastes. It was found that under hydrothermal reaction conditions, at temperatures of 160–225 °C, and in the presence of citric acid, the hydrolysis of cotton fibers to glucose and the subsequent dehydration of glucose to HMF were enhanced. The yield of HMF reached 12.5% for 60 min at 225 °C and 3.2% for 180 min at 160 °C. According to the chemical analysis of saccharides and organic acids in the product mixture, this process is fairly selective for the production of HMF and glucose, thereby facilitating the purification of HMF from hydrothermally treated materials.