A metal-free carbon dots for wastewater treatment by visible light active photo-Fenton-like reaction in the broad pH range

Defect-engineered dual Z-scheme core-shell MoS2/WO3-x/AgBiS2 for antibiotic and dyes degradation in photo and night catalysis: Mechanism and pathways

Water pollution caused by antibiotics and synthetic dyes and imminent energy crises due to limited fossil fuel resources are issues of contemporary decades. Herein, we address them by enabling the multifunctionality in dual Z-scheme MoS2/WO3-x/AgBiS2 across photolysis, photo Fenton-like, and night catalysis. Defect, basal, and facet-engineered WO3-x is modified with MoS2 and AgBiS2, which extended its photoresponse from the UV-NIR region, inhibited carrier recombination, and reduced carrier transfer resistance. The electric field rearrangement leads to a flow of electrons from MoS2 and AgBiS2 to WO3-x and intensifies the electron population, which is crucial for night catalysis. When MoS2/WO3-x/AgBiS2 was employed against doxycycline hydrochloride (DOXH), it removed 95.65, 81.11, and 77.92 % of DOXH in 100 min during photo-Fenton (PFR), night-Fenton (NFR), and photocatalytic (PCR) reactions, respectively. It also effectively removed 91.91, 98.17, 99.01, and 98.99 % of rhodamine B (RhB), Congo red (CR), methylene blue (MB), and methylene orange (MO) in Fenton reactions, respectively. ESR analysis consolidates the ROS generation feature of MoS2/WO3-x/AgBiS2 using H2O2 with and without irradiation. This work provides a strategy to eliminate the deficiencies of WO3-x and is conducive to the evolution of applications seeking to combat environmental and energy crises.

Insights into structural and functional regulation of chalcopyrite and enhanced mechanism of reactive oxygen species (ROS) generation in advanced oxidation process (AOP): A review

Chalcopyrite, renowned for its distinctive mixed redox-couple characteristics, exhibits excellent electron transfer properties both on its surface and within its crystal structure. This unique characteristic has attracted significant attention in various fields, including optics, electronics, and magnetism, as well as demonstrated remarkable catalytic efficacy in the environmental field. The rapid and effective electron transfer capability of a catalyst is crucial for advanced oxidation processes (AOPs). However, the performance of CuFeS2 in AOPs is hindered by its low electron transfer efficacy. This review aims to summarize the key steps and mechanisms of chalcopyrite-induced AOPs and provide strategies for enhancing effective electron transfer efficacies by controlling the structure and function of synthetic/natural chalcopyrite. These strategies include enhancing the catalytic performance of chalcopyrite and constructing composites to enhance catalytic activity (e.g., chelating agents, heterojunctions). Additionally, the factors influencing the generation of reactive oxygen species in chalcopyrite-induced AOPs are investigated, such as the types and properties of oxidants (e.g., H2O2, peroxymonocarbonate), the microstructure of catalysts, and reaction conditions in catalytic systems (e.g., pH values, dosage, temperature). Future perspectives on the applications of chalcopyrite are presented at the end of this paper. Overall, this review assists in narrowing the scope of chalcopyrite studies in AOPs and aids researchers in optimizing synthetic/natural catalysts for contaminant treatment.

Antibacterial Carbon Dots: Mechanisms, Design, and Applications

The increase in antibiotic resistance promotes the situation of developing new antibiotics at the forefront, while the development of non-antibiotic pharmaceuticals is equally significant. In the post-antibiotic era, nanomaterials with high antibacterial efficiency and no drug resistance make them attractive candidates for antibacterial materials. Carbon dots (CDs), as a kind of carbon-based zero-dimensional nanomaterial, are attracting much attention for their multifunctional properties. The abundant surface states, tunable photoexcited states, and excellent photo-electron transfer properties make sterilization of CDs feasible and are gradually emerging in the antibacterial field. This review provides comprehensive insights into the recent development of CDs in the antibacterial field. The topics include mechanisms, design, and optimization processes, and their potential practical applications are also highlighted, such as treatment of bacterial infections, against bacterial biofilms, antibacterial surfaces, food preservation, and bacteria imaging and detection. Meanwhile, the challenges and outlook of CDs in the antibacterial field are discussed and proposed.

Resourcelized conversion of livestock manure to porous cage microsphere for eliminating emerging contaminants under peroxymonosulfate trigger

Pollution and resource waste caused by the improper disposal of livestock manure, and the threat from the release of emerging contaminants (ECs), are global challenges. Herein, we address the both problems simultaneously by the resourcelized conversion of chicken manure into porous Co@CM cage microspheres (CCM-CMSs) for ECs degradation through the graphitization process and Co-doping modification step. CCM-CMSs exhibit excellent performance for ECs degradation and actual wastewater purification under peroxymonosulfate (PMS) initiation, and show adaptability to complex water environments. The ultra-high activity can maintain after continuous operation over 2160 cycles. The formation of C-O-Co bond bridge structure on the catalyst surface caused an unbalanced electron distribution, which allows PMS to trigger the sustainable electron donation of ECs and electron gain of dissolved oxygen processes, becoming the key to the excellent performance of CCM-CMSs. This process significantly reduces the resource and energy consumption of the catalyst throughout the life cycle of production and application.

Efficient electron transfer and copper species transformation under the synergy of BiVO4 and novel Cu2(OH)3F nanosheets

Here, we report a simple and efficient strategy for evenly in situ growth of Cu₂(OH)₃F nanosheets on BiVO₄ spheres as a novel photo-Fenton-like catalyst using hydrothermal method. The Cu₂(OH)₃F/BiVO₄ composite catalysts showed great performance for the organic pollutants degradation under visible light irradiation due to the efficient electron transfer and copper species transformation. The synergetic between Cu₂(OH)₃F and BiVO₄ not only promoted the separation of electrons and holes but also enhanced the Cu²⁺ reduction, thus produced more strong oxidative radicals under a wide pH value range. The activity of Cu₂(OH)₃F/BiVO₄ composite for methylene blue degradation was 6.03 and 5.47 times more than that of pristine Cu₂(OH)₃F and BiVO₄, respectively. The composite catalysts were characterized with various methods and their stability and adaptability were also evaluated. Finally, a possible photo-Fenton-like reaction mechanism was also proposed based on the band structure/position and reaction species.

Persistent free radicals in biochar enhance superoxide-mediated Fe(III)/Fe(II) cycling and the efficacy of CaO2 Fenton-like treatment

Superoxide radicals (O₂^•-) produced by the reaction of Fe(III) with H₂O₂ can regenerate Fe(II) in Fenton-like reactions, and conditions that facilitate this function enhance Fenton treatment. Here, we developed an efficient Fenton-like system by using calcium peroxide/biochar (CaO₂/BC) composites as oxidants and tartaric acid-chelated Fe(III) as catalysts, and tested it for enhanced O₂^•--based Fe(II) regeneration and faster sulfamethoxazole (SMX) degradation. SMX degradation rates and peroxide utilization efficiencies were significantly higher with CaO₂/BC than those with CaO₂ or H₂O₂ lacking BC. The CaO₂/BC system showed superior activity to reduce Fe(III), while kinetic analyses using chloroform as a O₂^•- probe inferred that the O₂^•- generation rate by CaO₂/BC was one-half of that by CaO₂. Apparently, O₂^•- is utilized more efficiently in this system to regenerate Fe(II) and enhance SMX degradation. Additionally, a positive correlation between SMX degradation rate constants and EPR signal intensities of biochar-derived persistent free radicals (PFRs) in CaO₂/BC was obtained. We postulate that PFRs enhanced Fe(III) reduction by shuttling electrons donated by O₂^•-. This represents a new strategy to augment the ability of superoxide to accelerate Fe(III)/Fe(II) cycling for increased hydroxyl radical production and organic pollutant removal in Fenton-like reactions.