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Perfluorooctanoic acid (PFOA) has drawn increasing attention as a highly persistent organic pollutant. The inherent stability, rigidity and potential toxicities characteristics make it a challenge to develop efficient technologies to eliminate it from water. Photocatalytic technology, as one advanced method, has been widely used in the degradation of PFOA in water. In this review, recent progress in the design of photocatalysts including doping, defects engineering, heterojunction and surface modification to boost the photocatalytic performance toward PFOA is summarized. The relevant degradation mechanisms were also discussed in detail. Finally, future prospect and challenges are proposed. This review may provide new guidelines for researchers to design much more efficient photocatalysts applied in the elimination of PFOA. [Display omitted] • Photocatalytic degradation of PFOA from water was reviewed. • Multiple strategies for improving degradation efficiency of PFOA were categorized. • The underlying degradation mechanisms of PFOA were summarized. • Future prospect and challenges toward photocatalytic degradation of PFOA from water were proposed. [ABSTRACT FROM AUTHOR]

The piezoelectric polarization electric field induced by the non-centrosymmetric triangular holes of g-C 3 N 4 was beneficial to promote the separation and transport of photogenerated carrier. The porous structure of porous tubular g-C 3 N 4 (PTCN) facilitated the absorption of visible light, and its thin and highly extended cambered tube wall lamellae and large specific surface area per unit cross-sectional area facilitated the response of mechanical vibration, thus improving the piezo-photocatalytic performance. The piezo-photocatalytic degradation rates of tetracycline hydrochloride (TCH), ciprofloxacin (CIP), rhodamine B (RhB) and methylene blue (MB) by PTCN were 89%, 51%, 100% and 100% within 30 min, respectively. The yield of H 2 O 2 reached 196.6 μM within 120 min. Photocurrent intensity, finite element simulation, DFT calculation, PFM and free radical quantification experiments were conducted to explain the reason for the high piezoelectric performance of PTCN, and the reason for the higher piezoelectric properties of the tubular structure than the bulk structure was also analyzed in depth. This work filled the research gap of tubular g-C 3 N 4 in piezo-photocatalysis and made up the research gap of the influence of material morphology structure on piezoelectric properties, which provided a new reference and incentive for future piezoelectric photocatalysis research. [Display omitted] • Porous tubular g-C 3 N 4 was obtained by simple wet precursors calcination. • Thin tube wall improved the piezo-photocatalytic performance of tubular g-C 3 N 4. • DFT calculation and finite element simulation revealed piezoelectric properties of PTCN. • Piezoelectricity enhanced photogenerated carrier separation and radical generation. [ABSTRACT FROM AUTHOR]

• In this paper, MnTiO3 nanoparticles doped with g-C3N4 micro-nanosheets were prepared and characterized with good performance using in situ growth method. • MnTiO3/CN can exhibit superior electrochemical hydrogen precipitation performance compared to the mono-material. • The doping of MnTiO3 leads to more nitrogen defects on the surface of g-C3N4, which results in more electrochemically active sites on the surface of the • Prepared heterojunction composite samples, enabling them to make an effective improvement in electrochemical properties. Z-scheme semiconductor heterostructure promotes the practical separation of electron-hole pairs and enhances the carrier separation efficiency, which has broad application prospects in efficient electrocatalytic hydrogen production (HER). However, it remains a significant challenge to construct high-quality directly Z-scheme heterostructure effectively. In this work, the construction of stable and controllable two-dimensional (2D) Z-scheme MnTiO 3 /C 3 N 4 (MTO/CN) heterostructure via In-situ growth strategy is obtained. This strategy relies mainly on the cooperation of ligand covalent bonds arising from the controlled growth of precursors and the tendency of metal ions to acquire stable electronic configurations. Benefiting from the unique electronic structure of heterostructure, the excellent performance of HER based on the MTO/CN heterostructure is systematically investigated. It reveals that the overpotential of the MTO/CN heterostructure is only 357 mV at 10 mA cm2, which is 2.02 times lower compared to the pure g-C 3 N 4. At the same time, the ESCA results show that the value of C dl of the heterostructure is 42.79 mF cm−2, which is 6.26 times higher compared to the pure g-C 3 N 4. Furthermore, this strategy provides new insight and theoretical guidance for the design of the Z-scheme semiconductor heterostructure. Schematic diagram of electrochemical hydrogen precipitation of MnTiO 3 /CN heterojunction composites prepared by in situ growth method. [Display omitted] [ABSTRACT FROM AUTHOR]

As one of the most important transportation hubs and industrial bases in China, Zhengzhou has suffered from serious PM 2.5 pollution for a long time. However, the investigation of contamination status and possible exposure risks of environmentally persistent free radicals (EPFRs) in PM 2.5 from Zhengzhou is rare. In this work, a comprehensive study of pollution levels, seasonal variations, sources, and potential health risks of PM 2.5 -bound EPFRs in Zhengzhou was conducted for the first time. The atmospheric concentrations of EPFRs in PM 2.5 from Zhengzhou ranged from 1.732 × 1012 spin m−3 to 7.182 × 1014 spin m−3 between 2019 and 2020. Relatively serious contamination was noticed in winter and spring. Primary fossil fuel combustion and Fe-mediated secondary formation were apportioned as possible sources of PM 2.5 -bound EPFRs in Zhengzhou. Moreover, to avert the bias of the toxicity assessment induced by utilization of incompletely extracted EPFRs from sample filter, simulatively generated EPFRs were applied to toxicological evaluations (cell viability and reactive oxygen species assays). Corresponding experimental dosages were based on the estimated adults' annual exposure amounts of EPFRs in real PM 2.5 samples. The results elucidated that EPFRs might cause growth inhibition and oxidative stress of human lung cells, suggesting the possible exposure-induced health concerns for local people in Zhengzhou. This study provides practical information of real contamination status of PM 2.5 -bound EPFRs in Zhengzhou, which is favorable to local air pollution control and reduction of exposure risks on public health in central China. [Display omitted] ● Pollution characteristics of PM 2.5 -bound EPFRs in Zhengzhou were firstly studied. ● Fossil fuel combustion and Fe-mediated secondary formation were possible sources. ● Toxicity studies revealed potential exposure risks of EPFRs in PM 2.5 from Zhengzhou. [ABSTRACT FROM AUTHOR]

Tetracycline (TCN) is a typical antibiotic with ecological toxicity, which is easy to cause bacterial drug resistance. Single-atom catalysts have a broad application prospect in the remediation of antibiotic polluted water by activated persulfate (PDS), but its catalytic properties are limited because of its high surface energy and easy aggregation. Therefore, in our manuscript, a novel nitrogen doped magnetic graphene oxide confined Fe-Co dual single-atom catalyst (Fe/Co(1:1) (S) -NMGO) was prepared by one-step molten salt assisted high temperature pyrolysis. XPS and AC-HAADF-STEM analysis indicated single-atom Fe and Co existed. Fe and Co atoms were bound to the material mainly through coordination with pyridinic N and pyrrolic N. While single-atom Fe and Co were simultaneously introduced into the modified materials, the removal rate of TCN reached 93.1%, implying the significant synergistic effect of single-atom Fe and Co on TCN removal. Molten salt assisted high-temperature pyrolysis significantly improved the TCN degradation rate. In addition, this research showed that the existence of magnetite nanoparticles was beneficial to improve the separation performance of the single-atom catalysts as well as the catalytic performance. At the same time, the effects of some key parameters (Fe/Co molar ratio, catalyst dosage, PDS dosage, initial pH, coexisting anions and humic acids) on TCN degradation in Fe/Co(1:1) (S) -NMGO/PDS system were also investigated. The catalytic potential in actual water and regeneration performance of the material were also evaluated. The possible activation mechanism and degradation pathway of TCN were proposed. These findings will provide important reference for the future design and application of single-atom-involved catalysts. [Display omitted] • Fe/Co dual single-atom catalyst was prepared by molten salt assisted pyrolysis. • Molten salts could provide a high polarity environment to destroy metal-metal bond. • Single Fe and Co atoms anchored on NMGO are verified by AC-HAADF-STEM. • TCN removal rate in this system could reach 93% at low catalyzer and PDS dosage. • Free radical (SO 4 •− >O 2 •− >HO•) oxidation were the main degradation mechanisms. [ABSTRACT FROM AUTHOR]

• Sm3+/Tm3+ co-doped BiVO 4 micro-squares were synthesized. • Sm3+/Tm3+ co-doping reduced the recombination of photogenerated electrons and holes. • Sm3+/Tm3+ co-doping provides additional light absorption. • Sm3+/Tm3+ co-doping brings about the remarkable photocatalytic activity for CO and CH 4 production. Solar-driven photocatalytic reduction of CO 2 to fuels and chemicals with added value has attracted intense attention. Here, the Sm3+/Tm3+ co-doped BiVO 4 micro-squares were synthesized by hydrothermal method. The prepared samples were characterized by some physicochemical methods such as XRD, FT-IR, SEM, TEM, XPS, UV–Vis DRS, EPR, N 2 physisorption -desorption and electrochemical analysis. The CO 2 reduction ability of the catalysts with different rare earth content was evaluated under xenon lamp irradiation. We found that BiVO 4 photocatalyst co-doped with 10%Sm and 10%Tm (mole percent) showed the remarkable photocatalytic activity for CO and CH 4 production. The CO production rate over 10%Sm/10%Tm/BiVO 4 was around 5 times higher than that of pure BiVO 4 and single rare earth doped BiVO 4. The enhanced activity can be attributed that the Sm3+/Tm3+ co-doping reduced the recombination rate of photogenerated electrons and holes, provides additional light absorption and more active sites for CO 2 reduction. Sm3+/Tm3+ co-doping can regulate the energy band structure and carrier separation of BiVO 4 which effectively boosts the CO photocatalytic reduction for CO and CH 4 production. [Display omitted] [ABSTRACT FROM AUTHOR]

The sulfate radical-based advanced oxidation processes (SR-AOPs) are considered to be efficient and environmentally friendly for handling persistent organic pollutants issues. The activation of persulfate (PS) by biochar (BC) materials derived from waste biomass is the current research hotspot in SR-AOPs. Herein, we propose bimetal modified peanut hull-derived biochar (BC-Fe-1-Zn) catalysts to activate PS to degrade tetracycline (TC) with a removal efficiency of 90% in 120 min. The physicochemical properties and reaction mechanisms are well studied through the effective combination of various characterization techniques and experiments. SO 4 •– , •OH and electron transfer are all involved in the degradation of TC and SO 4 •– is the main reactive oxygen species (ROSs). The Fe and Zn oxides and the oxygen-containing functional groups on the catalyst surface are considered as the active sites for the reaction. Moreover, the influences of different factors (such as pH, catalyst dosage, PS dosage and coexisting ions) on the TC remove efficiency are studied. Simultaneously, the TC degradation products and its reasonable degradation paths are analyzed. This work provides new ideas for the rational design of biochar-supported bimetallic catalysts and revealed that using BC-Fe-1-Zn in AOPs technology to environmental remediation is a promising approach. [Display omitted] • Biochar is prepared from peanut hull and applied for activating PDS. • Transition metals Fe and Zn are successfully loaded on biochar to promote electron transfer. • The synthesized catalyst owns large specific surface area, abundant functional groups. • Sulfate radicals and hydroxyl radicals contributed to the degradation of TC. [ABSTRACT FROM AUTHOR]

Recently, a large quantity of carbon nanotubes (CNTs) enters the environment due to the increasing production and applications. More and more researches are focused on the fate and possible ecological risks of CNTs. Some literatures summarized the effects of CNTs on the chemical behavior and fate of pollutants. However, little reviewed the effects of CNTs on the biodegradation of pollutants. In general, the effects of CNTs on the biodegradation of pollutants and the related mechanisms were summarized in this review. CNTs have positive or negative effects on the biodegradation of contaminants by affecting the functional microorganisms, enzymes and the bioavailability of pollutants. CNTs may affect the microbial growth, activity, biomass, community composition, diversity and the activity of enzymes. The decrease of the bioavailability of pollutants due to the sorption on CNTs also causes the reduction of the biodegradation of contaminants. In addition, the roles of CNTs are controlled by multiple mechanisms, which are divided into three aspects i.e., properties of CNTs, environment condition, and microorganisms themself. The better understanding of the fate of CNTs and their impacts on the biochemical process in the environment is conducive to determine the release of CNTs into the environment. Image 1 • The effects of carbon nanotubes on the properties of microorganisms were summarized. • Multiple toxicity mechanisms of carbon nanotubes to microorganisms were discussed. • The microbial protection and adaption mechanisms to carbon nanotubes were summarized. • The effects of carbon nanotubes on enzyme-catalyzed oxidation were summarized. • Reduced bioavailability of pollutants resulted in limited biodegradation. [ABSTRACT FROM AUTHOR]