In recent years, the utilization of phosphorus-enriched biochar (PBC) has attracted significant attention due to its exceptional stability and surface reactivity. This review systematically summarizes the advancements in research related to the application of PBC as an adsorbent for remediating water contaminated with heavy metals. Initially, the precursors utilized in the production of PBC, encompassing biomass and phosphorus sources, are introduced. Subsequently, the distinct physicochemical properties and adsorption characteristics resulting from phosphorus doping on the biochar surface through various carbonization processes and parameters are elucidated. Additionally, the diverse adsorption mechanisms employed by PBC in removing heavy metals from water are analyzed. Lastly, future research prospects and associated challenges concerning PBC are presented. This paper aims to furnish comprehensive background information for the practical implementation of PBC in the purification of heavy metal-contaminated water environments.

Metal sulfides are abundant in nature. They also have excellent catalytic qualities and tunable electronic structures. These characteristics make them extremely attractive materials advanced oxidation processes (AOPs) in wastewater treatment. In this review, the relationship between structure and property in monometallic and bimetallic sulfides is examined in detail. The key point is to introduce their working mode - activating peroxymonosulfate (PMS), peroxydisulfate (PDS) and hydrogen peroxide to generate reactive oxygen species. The key methods for improving catalytic performance were elaborated in detail. This includes the rational design of bimetallic sulfides, introduction of sulfur vacancies, non-metal doping and in-situ regeneration techniques. These methods can adjust the electronic configuration, expose active sites and accelerate the metal redox cycling effectively. This greatly enhances the degradation efficiency and maintains the stability of the catalyst. This review also studies the environmental factors that affect catalytic performance. It points out future directions for developing metal sulfide-based catalysts. These directions are for their practical use in water remediation.