A feasibility study of kitchen waste and waste bentonite as adsorbent for P-containing wastewater treatment: performance and mechanism

The reuse of solid wastes has awakened much attention and triggered extensive research, especially given the fact that kitchen waste (KW) and waste bentonite as typical solid wastes are increasing rapidly worldwide. In this work, the KW and waste bentonite were co-valorized to produce KW-bentonite (KWB) adsorbent at the mass ratio of 7:3 at 1000 °C. The effects of adsorbent dose, solution pH, and coexisting substances on the phosphate removal by KWB adsorbent were explored in a batch system, achieving the maximum adsorption capacity of 23.04 mg/g. Besides, it could be seen that the adsorption process of phosphate by KWB adsorbent depends on chemisorption through the analysis of thermodynamic and kinetic results. The properties of KWB adsorbent were analyzed to explore the adsorption process while an economic analysis was conducted to identify the practical application potential of KWB adsorbent for P-contaminated wastewater. In conclusion, the present study not only offers new insights into the synergistic effect of kitchen waste and waste bentonite for environmental pollution control, but also provides a feasible waste-to-wealth strategy for converting kitchen waste and waste bentonite into KWB adsorbent that can be used as an effective phosphate adsorbent. Graphical Abstract