Recently, biochar has emerged as a promising option for environmentally friendly remediation due to its cost-effectiveness, extensive surface area, porosity, and exceptional electrical conductivity. Biochar-based advanced oxidation procedures (BC-AOPs) have gained popularity as an effective approach to breaking down organic pollutants in aqueous environments. It is commonly recognized that the main reactive locations within BC-AOPs consist of functional groups found on biochar, which encompass oxygen-containing groups (OCGs), imperfections, and persistent free radicals (PFRs). Additionally, the existence of metallic components supported on biochar and foreign atoms doped into it profoundly impacts the catalytic mechanism. These components not only modify the fundamental qualities of biochar but also serve as reactive sites. Consequently, this paper offers a comprehensive review of the raw materials, preparation techniques, modification approaches, and composite catalyst preparation within the biochar catalytic system. Special attention is given to explaining the modifications in biochar properties and their impacts on catalytic activity. This paper highlights degradation mechanisms, specifically pathways that include radical and non-radical processes. Additionally, it thoroughly examines the importance of active sites as catalysts and the basic catalytic mechanism of BC-AOPs. Finally, the potential and future directions of environmental remediation using biochar catalysts and advanced oxidation processes (AOPs) are discussed. Moreover, suggestions for future advancements in BC-AOPs are provided to facilitate further development.

Efficient extraction of Li from brine at a low cost is becoming a key technology to solve energy and environmental problems. Electrochemical extraction of Li has become a research hotspot due to its low energy consumption, high selectivity, and environmental friendliness. LiMn₂O₄, LiFePO₄, and LiNi_1/3Co_1/3Mn_1/3O₂ are widely used as cathode materials for the electrochemical extraction of Li but they also have some drawbacks, such as a small adsorption capacity. In this paper, the principle of electrochemical Li extraction from brine is reviewed and the research progress and analysis of the above three working electrode materials is summarized. In addition, analysis of the extraction of other rare ions from the working electrode material and the effect of micro-organisms on the working electrode material is also presented. Next, the shortcomings of working electrode materials are expounded upon and the research direction of working electrode materials in electrochemical Li extraction technology are prospected. It is hoped that this paper can provide insights and guidance for the research and application of electrochemical Li extraction from brine.

A large number of pathogenic microorganisms exist in medical wastewater, which could invade the human body through the water and cause harm to human health. With the global pandemic coronavirus (COVID-19), public health safety become particularly important, and medical wastewater treatment is an important part of it. In particular, electrochemical disinfection technology has been widely studied in medical wastewater treatment due to its greenness, high efficiency, convenient operation, and other advantages. In this paper, the development status of electrochemical disinfection technology in the treatment of medical wastewater is reviewed, and an electrochemical three-stage disinfection system is proposed for the treatment of medical wastewater. Moreover, prospects for the electrochemical treatment of medical wastewater will be presented. It is hoped that this review could provide insight and guidance for the research and application of electrochemical disinfection technology to treat medical wastewater.

To evaluate the efficacy of biochelators for phytoremediation of cadmium (Cd), effects of biochelators (humic acid, HA; polyaspartic acid, PASP; rhamnolipid, RLs) and synthetic chelator (sodium tripolyphosphate, STPP) on the growth, accumulation, and antioxidant index of Cd were investigated in Iris sibirica L. The results indicated that the addition of HA increased the dry weight of leaves and stems, and the addition of PASP, RLs, and STPP increased the growth of leaves but inhibited the growth of stems. The determination of Cd accumulation indicated that HA decreased the content of Cd in all tissues, while the addition of PASP, RLs, and STPP increased the accumulation of Cd in stems and roots. In addition, the determination of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activities indicated that the treatment of PASP and RLs increased the activities of antioxidant enzymes, which might be beneficial to the resistance of Cd for Iris sibirica L. Overall, these results indicated that biochelators may improve the phytoremediation efficacy of Iris sibirica L. on Cd polluted paddy field. Among the tested chelators, PASP exhibited the best comprehensive efficacy and the highest commercial potential.

Due to their substantial biomass and rapid growth, emergent plants found in wetlands are viewed as excellent sources for biochar production, which has been demonstrated to serve as an effective substitute for absorbite in the effluent treatment. This article systematically contrasted the physicochemical properties of biochar derived from each section of Iris sibirica L. (designated as BC_R, BC_S, and BC_L) under identical pyrolysis conditions, in order to assess their effectiveness in removing cadmium (Cd) from effluent. Experimental results indicated that the removal efficiencies of Cd among the various biochars followed the order BC_S (19.92 mg/g) > BC_L (19.89 mg/g) > BC_R (13.22 mg/g). The removal of Cd²⁺ by biochar is primarily governed by chemisorption, as described by the Langmuir and Freundlich models. Moreover, different adsorption kinetic models, e.g., first-order kinetics, second-order kinetics, intra-particle diffusion, and the Elovich model, were performed to elucidate the adsorption process. Compared to BC_L and BC_R, the proportions of ion exchange and precipitation were more superior in BC_S, reaching 54% and 31%, respectively, which could serve as an effective adsorbent for metal ions, achieving the maximum adsorption capacity. In addition, precipitation (46%) was predominant during the Cd²⁺ adsorption process through BC_R. Therefore, BC_R was more suitable for the acidic wastewater treatment. This study provided an in-depth understanding of the cadmium removal behavior through biochar obtained from different part (roots, stems, and leaves) of wetland plants and introduced a new option for efficient utilization of waste biomass.