One-pot hydrothermal synthesis of MoS2 modified sludge biochar for efficient removal of tetracycline from water

Efficient removal of tetracycline (TC) has become a global challenge because the unsatisfactory removal rate of traditional sewage treatment technology. A carbon-based material (MoS 2 @SBC) was synthesized by one-pot hydrothermal method using municipal sludge as the feedstock to remove TC from water. Characterization analysis showed that MoS 2 @SBC had abundant functional groups (e.g., -OH, C O, S H) and large surface area. The maximum adsorption capacity of MoS 2 @SBC for TC could reach 229.2 mg/g at 298 K. Elovich model and Langmuir model better fitted the kinetics and isotherms data, respectively, which illustrated that chemisorption dominated the process of TC adsorption onto MoS 2 @SBC. Liquid film diffusion and intraparticle diffusion simultaneously controlled the adsorption process. The thermodynamics study described that adsorption was a spontaneous, endothermic and randomness increasing process. The ionic species/strength and solution pH were the critical factors affecting the adsorption process. The kinetics, isotherms and thermodynamics analysis, together with characterization results demonstrated that π-π conjugation, H-bonding, electrostatic interaction and pore filling were the main adsorption mechanisms. Additionally, the adsorption capacity of MoS 2 @SBC for TC in the actual waters (Yangtze River water and Nanhu Lake water) was inhibited. Furthermore, NaOH regeneration could maintain the sustainable adsorption performance of MoS 2 @SBC. This study developed a promising adsorbent for TC removal and provided a resource utilization approach for sludge.