A comprehensive synergistic study of process parameters on co-hydrothermal carbonization of digested sewage sludge and sugarcane bagasse: Hydrochar yield, lead adsorption capacity, and physicochemical properties

Abstract

The hydrothermal carbonization approach applies to waste management, clean water supply, and the creation of valuable materials. An appropriate adsorbent using bagasse and sewage sludge was synthesized via co-hydrothermal carbonization for efficient lead removal. The effect of process parameters on adsorption capacity, hydrochar yield, and synergistic properties was thoroughly examined. Results showed that sensitive positive adsorption synergy occurred at higher sludge/bagasse ratios, while moderate positive and negative yield synergy was achieved at lower and higher temperatures, respectively. Due to the co-hydrothermal carbonization process, the maximum experimental adsorption capacity increased from 105 to 140 mg/g compared to the predicted value. In addition, during the first 10 min of adsorption, mean adsorption speeds of 108 mg/g and 75 mg/g were achieved for experimental and predicted values, respectively. Moreover, at an equilibrium concentration of 0.5 mg/g, the experimental equilibrium adsorption capacity increased from 42.2 to 98.3 mg/g compared to the expected value. This foundational research provides basic information on the adsorption ability of hydrochar in the co-hydrothermal carbonization process and presents an environmentally friendly approach to waste management and clean water supply.