Preparation of heterojunction C3N4/WO3 photocatalyst for degradation of microplastics in water

Multi-active photocatalysts of biochar-doped g-C3N4 incorporated with polyoxometalates for the high-efficient degradation of sulfamethoxazole

Sulfamethoxazole (SMX) is one of major antibiotic contaminants in current aqueous environment. In this paper, waste loofah and melamine were co-carbonized to prepare biochar-doped g-C3N4 (CCN) by a one-pot method and then combined with Co2PMo11VO40 (CoPMoV) using a binder to obtain the novel polyoxometalates (POMs) photocatalytic composites (CCN/CoPMoV). The incorporation of CoPMoV dramatically reduced the photogenerated carrier recombination and led to a small band gap. Under visible light, the synergetic activation from biochar, g-C3N4 and POMs can remove 98.5% of SMX (k = 0.215 min-1) in the peroxymonosulfate (PMS) system within 20 min and keep its high stability with the degradation of 88.9% after five cycles. Multi-active sites from CCN/CoPMoV are contributed to develop the most active species of SO4-∙, ·OH, 1O2, and h+. The validity in the degradation of SMX makes CCN/CoPMoV a promising and potential material for the removal of aqueous pollutants in the future.

All-inorganic lead halide perovskites for photocatalysis: a review

Nowadays, environmental pollution and the energy crisis are two significant concerns in the world, and photocatalysis is seen as a key solution to these issues. All-inorganic lead halide perovskites have been extensively utilized in photocatalysis and have become one of the most promising materials in recent years. The superior performance of all-inorganic lead halide perovskites distinguish them from other photocatalysts. Since pure lead halide perovskites typically have shortcomings, such as low stability, poor active sites, and ineffective carrier extraction, that restrict their use in photocatalytic reactions, it is crucial to enhance their photocatalytic activity and stability. Huge progress has been made to deal with these critical issues to enhance the effects of all-inorganic lead halide perovskites as efficient photocatalysts in a wide range of applications. In this manuscript, the synthesis methods of all-inorganic lead halide perovskites are discussed, and promising strategies are proposed for superior photocatalytic performance. Moreover, the research progress of photocatalysis applications are summarized; finally, the issues of all-inorganic lead halide perovskite photocatalytic materials at the current state and future research directions are also analyzed and discussed. We hope that this manuscript will provide novel insights to researchers to further promote the research on photocatalysis based on all-inorganic lead halide perovskites.

Application of advanced oxidation processes for the removal of micro/nanoplastics from water: A review

Micro/nanoplastics (MNPs) have been increasingly found in environments, food, and organisms, arousing wide public concerns. MNPs may enter food chains through water, posing a threat to human health. Therefore, efficient and environmentally friendly technologies are needed to remove MNPs from contaminated aqueous environments. Advanced oxidation processes (AOPs) produce a vast amount of active species, such as hydroxyl radicals (·OH), known for their strong oxidation capacity. As a result, an increasing number of researchers have focused on using AOPs to decompose and remove MNPs from water. This review summarizes the progress in researches on the removal of MNPs from water by AOPs, including ultraviolet photolysis, ozone oxidation, photocatalysis, Fenton oxidation, electrocatalysis, persulfate oxidation, and plasma oxidation, etc. The removal efficiencies of these AOPs for MNPs in water and the influencing factors are comprehensively analyzed, meanwhile, the oxidation mechanisms and reaction pathways are also discussed in detail. Most AOPs can achieve the degradation of MNPs, mainly manifest as the decrease of particle size and the increase of mass loss, but the mineralization rate is low, thus requiring further optimization for improved performance. Investigating various AOPs is crucial for achieving the complete decomposition of MNPs in water. AOPs will undoubtedly play a vital role in the future for the removal of MNPs from water.

Visible light-induced catalytic performance of composite photocatalyst synthesized with nanomaterials WO3 and two-dimensional ultrathin g-C3N4

To improve the visible light-induced catalytic activities of Ultrathin g-C3N4 (UCN), a promising photocatalyst WO3/UCN (WU) was synthesized. Its visible light-driven photocatalysis performance was controllable by adjusting the theoretical mass ratio of WO3/UCN. We have calibrated the optimal preparation conditions to be: WO3/UCN ratio as 1:1, the stirring time of the UCN and sodium tungstate mixture as 9 h and the volume of concentrated hydrochloric acid as 6 mL which was poured into the mixture solution with an extra stirring time of 1.5 h. The optimal photocatalyst WUopt had porous and wrinkled configurations. Its light absorption edge was 524 nm while that of UCN was 465 nm. The band gap of WUopt was 2.13 eV, 0.3 eV less than that of UCN. Therefore, the recombination rate of photo-generated electron-hole pairs of WUopt reduced significantly. The removal rate of WUopt on RhB was 97.3%. By contrast, the removal rate of UCN was much lower (53.4%). WUopt retained a high RhB removal rate, it was 5.5% lower than the initial one after being reused for five cycles. The photodegradation mechanism was facilitated through the strong oxidation behaviors from the active free radicals ·O2-, ·OH and h+ generated by WUopt under the visible light irradiation.