Excellent Degradation Performance Research Articles

Ultrafine CoNi alloy nanoparticles anchored on surface-roughened halloysite nanotubes for highly efficient catalytic hydrogenation of 4-nitrophenol

The hydrogenation of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) is an effective and cost-competitive procedure to change waste into valuables. With the purpose of designing efficient and green catalysts to convert 4-NP, we adopt halloysite nanotubes (HNTs), a resource-rich and eco-friendly clay mineral material, as CoNi alloy nanoparticles support in this study. The HNTs used have been increased the surface roughness (defined as rHNTs) through the etching process. Thereafter, a series of ultrafine CoNi alloy nanoparticles (1.2 ∼ 1.4 nm) anchored onto rHNTs (CoxNi1-x/rHNTs, where x represents the molar percentage of Co to total metal elements) are successfully synthesized via a simple one-pot approach. Benefitting from the positive synergy of Co and Ni bimetals and the powerful metal-support interaction, Co0.7Ni0.3/rHNTs catalyst (8.55 wt% total actual metal loading) exhibits the best catalytic performance for 4-NP degradation with a conversion efficiency of 99 % within 4 min at 298 K, and meanwhile a high turnover frequency (TOF) of 1.16 × 10-2 mmol mg−1 min−1 is achieved with the rate constant of 1.09 min−1. Of note, Co0.7Ni0.3/rHNTs also show excellent degradation performance towards two other nitrophenol isomers (2-nitrophenol and 3-nitrophenol).

Synthesis of Ag2O/CaMoO4 S-type heterojunction with enhanced sonocatalytic performance to remove crystal violet in dye wastewater

Herein, an S-type of Ag2O/CaMoO4 heterojunction was prepared by combining CaMoO4 with Ag2O and characterized. The sonocatalytic performance of the Ag2O/CaMoO4 composite was evaluated by analyzing the degradation of basic dye crystal violet (CV). The results showed that the Ag2O/CaMoO4 composite had the best sonocatalytic performance when the molar ratio of Ag2O to CaMoO4 in the Ag2O/CaMoO4 composite was 10 %. When the ultrasonic time was 120 min, the ultrasonic power was 200 W, the addition amount of 10 % Ag2O/CaMoO4 composite was 1.00 g/L and the initial concentration of CV solution was 5 mg/L, the removal rate of CV could reach 97.36 ± 1.46(%). In addition, 10 % Ag2O/CaMoO4 composite showed excellent sonocatalytic degradation performance to cationic dyes Rhodamine B (RhB) and methylene blue (MB), anionic dye Orange II (AO II) and azo dye Congo red (CR), indicating that the catalyst had a wide range of application. The study on the mechanism of sonocatalysis showed that the construction of S-type Ag2O/CaMoO4 heterojunction effectively separated the electron-hole (e−-h+) pairs in the sonocatalysis process, significantly improved the sonocatalytic performance of CaMoO4, and effectively degraded CV, and the degradation of CV was caused by the active components such as h+, superoxide anion radical (O2–) and hydroxyl radical (OH). Furthermore, the 10% Ag2O/CaMoO4 composite showed excellent repeatability and stability. In addition, the sonocatalytic degradation products of CV were detected and the possible degradation pathways of CV were summarized. These results suggested that the Ag2O/CaMoO4 composite was an extremely appropriate sonocatalyst for sonocatalytic degradation of organic pollutants and would provide a valuable research basis for the development of efficient sonocatalysts.

Pyrazine-based iron metal organic frameworks (Fe-MOFs) with modulated O-Fe-N coordination for enhanced hydroxyl radical generation in Fenton-like process

Rational design of coordination environment of Fe-based metal-organic frameworks (Fe-MOFs) is still a challenge in achieving enhanced catalytic activity for Fenten-like advanced oxidation process. Here in, novel porous Fe-MOFs with modulated O-Fe-N coordination was developed by configurating amino terephthalic acid (H2ATA) and pyrazine-dicarboxylic acid (PzDC) (Fe-ATA/PzDC-7:3). PzDC ligands introduce pyridine-N sites to form O-Fe-N coordination with lower binding energy, which affect the local electronic environment of Fe-clusters in Fe-ATA, thus decreased its interfacial H2O2 activation barrier. O-Fe-N coordination also accelerate Fe(II)/Fe(III) cycling of Fe-clusters by triggering the reactive oxidant species mediated Fe(III) reduction. As such, Fe-ATA/PzDC-7:3/H2O2 system exhibited excellent degradation performance for typical antibiotic sulfamethoxazole (SMX), in which the steady-state concentration of hydroxyl radical (OH) was 1.6 times higher than that of unregulated Fe-ATA. Overall, this study highlights the role of O-Fe-N coordination and the electronic environment of Fe-clusters on regulating Fenton-like catalytic performance, and provides a platform for precise engineering of Fe-MOFs.

FeOOH Nanosheets Coupled with ZnCdS Nanoparticles for Highly Improved Photocatalytic Degradation of Organic Dyes and Tetracycline in Water.

Developing a low-cost and highly efficient semiconductor photocatalyst for the decomposition of organic pollutants and antibiotics is highly desirable. Herein, FeOOH nanosheets were prepared using a liquid-phase stirring technique and combined with ZnCdS (ZCS) nanoparticles to construct FeOOH/ZCS nanocomposite photocatalysts. The photocatalytic efficiency of the FeOOH/ZCS nanocomposite was evaluated for the decomposition of various pollutants, including rhodamine B, methylene Blue, and tetracycline. The FeOOH/ZCS nanocomposite exhibited significantly higher photocatalytic performance for the decomposition of various organics. Moreover, the optimized FeOOH/ZCS retained more than 90% of its initial photocatalytic activity even after five successful runs. Radical quenching test and electron spin resonance (ESR) analysis revealed that hydroxyl radicals (•OH) play a dominant role for the decomposition of organics. The FeOOH/ZCS Z-scheme heterojunction significantly facilitates higher charge transfer efficiency and the generation of reactive radicals, resulting in excellent photocatalytic degradation performance. This work offers a new approach to synthesis FeOOH-based photocatalyst for the elimination of organics and antibiotics in water.

Enhanced degradation of emerging contaminants by Far-UVC photolysis of peracetic acid: Synergistic effect and mechanisms

Krypton chloride (KrCl*) excimer lamps (222 nm) are used as a promising irradiation source to drive ultraviolet-based advanced oxidation processes (UV-AOPs) in water treatment. In this study, the UV222/peracetic acid (PAA) process is implemented as a novel UV-AOPs for the degradation of emerging contaminants (ECs) in water. The results demonstrate that UV222/PAA process exhibits excellent degradation performance for carbamazepine (CBZ), with a removal rate of 90.8 % within 45 min. Notably, the degradation of CBZ in the UV222/PAA process (90.8 %) was significantly higher than that in the UV254/PAA process (15.1 %) at the same UV dose. The UV222/PAA process exhibits superior electrical energy per order (EE/O) performance while reducing resource consumption associated with the high-energy UV254/PAA process. Quenching experiments and electron paramagnetic resonance (EPR) detection confirm that HO• play a dominant role in the reaction. The contributions of direct photolysis, HO•, and other active species (RO• and 1O2) are estimated to be 5 %, 88 %, and 7 %, respectively. In addition, the effects of Cl−, HCO3−, and humic acid (HA) on the degradation of CBZ are evaluated. The presence of relatively low concentrations of Cl−, HCO3−, and HA can inhibit CBZ degradation. The UV222/PAA oxidation process could also effectively degrade several other ECs (i.e., iohexol, sulfamethoxazole, acetochlor, ibuprofen), indicating the potential application of this process in pollutant removal. These findings will propel the development of the UV222/PAA process and provide valuable insights for its application in water treatment.

In situ alkali‐free growth of octahedral Ag2O nanoparticles by bacterial cellulose for efficient antibacterial application

AbstractUniform octahedral Ag2O nanoparticles were in situ synthesized within natural bacterial cellulose (BC) films without any inorganic alkali. The morphological transformation of Ag2O from nanoparticles and small nanoplates to an octahedral structure was well controlled by varying the UV exposure time. To reduce and anchor Ag2O nanoparticles, abundant hydroxyl groups on the surface of natural BC fibers ensured an ideal environment for the mild redox reaction between Ag+ and –OH groups. The structural features and structure–activity relationship of Ag2O/BC films were confirmed through TEM, energy dispersive spectroscopy assisted SEM analysis, Fourier transform IR, X‐ray photoelectron spectroscopy, TGA and XRD. The structure–antibacterial activity relationship of the Ag2O/BC films was proved against both Gram‐positive (Staphylococcus aureus) and Gram‐negative (Escherichia coli) bacteria. They also showed excellent performance in the photocatalytic degradation of organic dyes. Ag2O/BC films have potential bactericidal applications in the field of pharmacy, specifically for wound dressing and flexible wearable materials. © 2024 Society of Chemical Industry.

One-step thermal oxidation synthesis of carbon-doped TiO2 with enhanced photocatalytic activity using CO2 as the carbon source

The study proposed a simplified carbon doping synthesis strategy to enhance the photocatalytic activity of titanium dioxide (TiO2). Utilizing CO2 gas as the carbon source, the material was directly synthesized onto a titanium substrate through a one-step thermal oxidation method. Raman and XPS analyses indicated that with the increase in CO2 partial pressure, the influence of the carbon source was amplified, resulting in carbon doping in a graphite-like structure and the induction of oxygen vacancies. Electrochemical impedance spectroscopy and UV–vis spectra demonstrated that the introduced carbon species acted as a photosensitizer, augmenting the transfer of photogenerated carriers. Photoluminescence spectra suggested that oxygen vacancies could enhance the non-radiative scattering of photogenerated carriers. These two effects synergistically improved the photocatalytic activity of TiO2 significantly, although the degree of enhancement was dependent on the optimized ratio of carbon content to oxygen vacancy content. Only with optimal carbon content and oxygen vacancy levels could the undesired radiative recombination of photogenerated carriers be prevented, ensuring that the energy derived from visible light was effectively utilized to drive chemical reactions. Under these optimal conditions, the TC-O5 and TC-O10 samples exhibited excellent photocatalytic degradation performance of methyl orange under visible light, with degradation rates of 86.27% and 82.54%, respectively, and displayed outstanding cycling stability, with the degradation rate remaining above 90% for three cycles. This method proved to be simple, efficient, and easily operable, offering significant advantages for industrial-scale preparation.

Roles of B[sbnd]O[sbnd]Cu sites and graphite nitrogen on persulfate non-radical activation for tetracycline degradation

The activation of peroxymonosulfate (PMS) by carbon-based catalysts is deemed to be a promising method for the degradation of refractory organic contaminants in wastewater. Herein, a Cu-doping strategy in B and N co-doped carbon nanotubes with highly dispersed BOCu sites and graphite nitrogen were successfully synthesized for activating PMS to degradate tetracycline. The best removal rate of tetracycline within 60 min (97.63 %) was obtained by the 1.5 % Cu-BNC and the degradation rate was increased by 17.9 times. The enhanced catalyst activity was attributed to the promoting the cycle of the Cu(I)/Cu(II) redox pair by the formed BOCu sites, and the accelerating the electron transfer process by the adsorption of graphitic N for PMS. The non-free radical pathway including 1O2 and electron transfer played a dominant role in the 1.5 % Cu-BNC/PMS system. The degradation intermediates of TC were identified and three possible degradation pathways were proposed. Further toxicity analysis of the intermediates showed that the 1.5 % Cu-BNC/PMS system had a significant effect on weakening and reducing the biological toxicity and mutagenicity of TC. Moreover, it presented an excellent degradation performance in raw natural water. In general, the proposed regulation of carbon-based catalysts via the coordination-driven effect provides ideas for efficient wastewater treatment.

Effect of phase structure of Bi5O7I on the photocatalytic activity of S-scheme AgBr/Ag/Bi5O7I

The synthesis of pure needle-shaped monoclinic-Bi5O7I (m-Bi5O7I) was reached for the first time at pH 12.2 under a hydrothermal condition, using bismuth citrate as a Bi source. To enhance the photocatalytic activity of m-Bi5O7I, S-scheme AgBr/Ag/m-Bi5O7I (denoted as AAmB) was constructed via a photodeposition method. AAmB exhibited excellent photocatalytic degradation performance towards methylene blue (MB) under visible light illumination with apparent rate constants (0.01047 min−1), and it is approximately 4 times higher than that of AgBr/Ag/orthorhombic-Bi5O7I (plate-shaped) (called as AAoB) (0.00267 min−1) prepared at pH 12.5. Besides, the specific surface area of as-constructed AAmB heterojunction (18.5 m2·g−1) was also higher than that of AAoB (1.0 m2·g−1). These results indicate that the phase structure of Bi5O7I influences the morphology and specific surface area of the heterojunction. Furthermore, AAmB showed superior photodegradation activity for other pollutants, such as tetracycline (TC), bisphenol A (BPA), rhodamine B (RhB), etc. When bismuth nitrate was used as a raw material, only o-Bi5O7I was obtained at a wide pH range from 12 to 13, and the photocatalytic performance of the as-constructed AgBr/Ag/o-Bi5O7I heterojunction based on this o-Bi5O7I was notably lower than that of AAmB.

A Type-II CQDs regulating FeOOH decorated BiVO4 photoelectrode for highly efficient photoelectrochemical degradation of tetracycline

Bismuth vanadate (BiVO4) photoelectrode is of great potentials to be used for photoelectrochemical (PEC) removal of antibiotic pollutant. However, it still suffers from lower efficiency. Herein, a type-II FeOOH-CQDs/BiVO4 photoelectrode was fabricated via the in-situ growth of FeOOH nanoparticles over BiVO4 using Carbon quantum dots (CQDs) as mediator. Benefiting from the type-II heterojunction between BiVO4 and FeOOH, as well as the excellent charger transfer assisted by CQDs, FeOOH-CQDs/BiVO4 exhibited excellent PEC degradation performance towards a typical antibiotic- tetracycline (TC). In a typical PEC process, FeOOH-CQDs/BiVO4 photoelectrode (2 cm × 2 cm) yielded a high removal ratio of ∼ 99 % toward TC within 120 min at an applied potential of 0.6 V (vs. Hg/Hg2Cl2). Moreover, the PEC configuration was verified to be used for TC degradation in actual waters, such as tap water and lake water, with > 90 % of removal ratio. The radical trapping experiments revealed holes and superoxide radical dominated in the TC degradation process. This work provides an insight on the type-II heterojunction photoelectrode to enhance the PEC degradation of TC, which would help for the treatment of antibiotic wastewater.

Synthesis of Cu doped NiO for their antioxidant and photocatalytic properties: Green synthesis using Lycopodium Linn

Metal oxide nanoparticles produced by plant extracts are more stable and biocompatible in comparison with those produced by physical and chemical methods. This research focuses on the synthesis of pure and Cu doped NiO nanoparticles (NPs) using Phytolacca dodecandra L'Herit (P.d) leaf extract and evaluation of their antioxidant and photocatalytic activities. The obtained Cu-doped NiONPs have been characterized through X-ray diffraction (XRD), Transmission electron microscope (TEM), Fourier transform infrared (FT-IR), Ultraviolet-visible (UV–Vis), N2 adsorption-desorption and X-ray photoelectron spectra (XPS) analyses in different concentrations (1, 3, and 5 %) of copper at an optimum temperature of 400 °C. The photocatalytic activity of prepared samples was studied by degradation of Rose Bengal (RB) and Methylene Blue (MB) dye aqueous solutions. Under UV radiation for 60 min. 5-Cu-NiO nanophotocatalyst showed degradation efficiency of 98.7 % (0.5 mol/L), high apparent constant (0.9871 min−1) and long term stability towards MB dye. In the antioxidant test, NiO NPs and Cu−NiO NPs prevented the oxidation of 50 % of the H2O2 molecules at a concentration of 363.96 and 350.29 μg/mL, respectively. Moreover, the enhancement of the antioxidant activity of the biosynthesized NiO NPs might be an effect of copper ions present in the particles. Facile and green synthesis process with the excellent degradation performance demonstrates that the Cu doped NiO NPs have a great potential for wastewater treatment applications.

Preparation of 2D/2D CoAl-LDH/BiO(OH)XI1−X Heterojunction Catalyst with Enhanced Visible–Light Photocatalytic Activity for Organic Pollutants Degradation in Water

Hydrotalcite/bismuth solid solution (2D/2D CoAl-LDH/BiO(OH)XI1−X) heterojunction photocatalysts were fabricated through a hydrothermal route. Because of their identical layered structure and interlayer hydroxides, CoAl-LDH(2D) and BiO(OH)XI1−X(2D) form a tightly bonded heterojunction, resulting in efficient light absorption, excitation, and carrier migration conversion. At the same time, the large specific surface area and abundant hydroxyl groups of the layered structure make the heterojunction catalyst exhibit excellent performance in the photocatalytic degradation of organic pollutants. Under visible light irradiation and in the presence of 1 g/L of the catalyst, 10 mg/L of methyl orange (MO) in water could be completely degraded within 20 min, and the degradation rate of tetracycline (TC) reached 99.23% within 5 min. CoAl-LDH/BiO(OH)XI1−X still maintained good photocatalytic degradation activity of tetracycline after five cycles, and the structure of the catalyst did not change. The reaction mechanism related to the degradation of TC by photocatalytic reactions was explored in detail, and the photoexcitation of the semiconductor heterojunction, as well as the subsequent free radical reaction process and the degradation pathway of TC were clarified. This work provides a promising strategy for the preparation of efficient photocatalytic materials and the development of water purification technology.

Sulfur vacancy-induced 1T-MoS2 co-catalyst loaded on Zn3In2S6 for simultaneous promoting photocatalytic hydrogen evolution and pollutant degradation

In the field of photocatalytic hydrogen evolution, Zn3In2S6 has caught tremendous attention because of its suitable band gap and outstanding stability. However, the lower number of active sites as well as lower efficiency of photoproduced carrier separation restricted its further application. Introducing co-catalysts and structural defects are effective methods to solve the above problems. In this paper, Zn3In2S6 loaded metal phase MoS2 to construct flower-shaped spherical catalysts 1T-MoS2/Zn3In2S6 (M/ZIS6) with abundant sulfur vacancies. The visible-light-driven photocatalytic hydrogen evolution rate of 2.4 % M/ZIS6 was 8.71 mmol∙g−1·h−1, which far exceeded those of pure Zn3In2S6 (0.80 mmol∙g−1·h−1) and 2.4 % Pt/Zn3In2S6 (3.86 mmol∙g−1·h−1). Moreover, 2.4 % M/ZIS6 simultaneously displayed the excellent photocatalytic degradation performance toward acid orange 7 (AO7) in the hydrogen evolution reaction process. Co-catalyst metal phase 1T -MoS2, abundant sulfur defects, and a large and dense contact interface between 1T -MoS2 and Zn3In2S6 mainly contributed to the enhanced photocatalytic performance of 2.4 % M/ZIS6. This work provided a potential concept to construct efficient photocatalysts with noble metal-free co-catalyst for bifunctional applications.

Tribocatalytic activity in lithium borate-bismuth tungstate nanocrystal glass-ceramics

The harnessing and utilization of mechanical energy through frictional route have emerged as a promising avenue for advancing clean energy initiatives. Triboelectric charges are generated on the surface of two different materials during friction. These charges are similar to photocatalytic charges and can be utilized for dye degradation by a process called tribocatalysis. In this study, it was found that lithium borate bismuth tungstate (0.7Li2B4O7−0.3Bi2WO6) nanocrystal glass-ceramics synthesized by melt-quench technique exhibit excellent tribocatalytic dye degradation performance by harvesting friction energy. X-ray diffraction technique, Raman Spectroscopy and Transmission Electron Microscopy (TEM) was performed to examine the structure, phase, and microstructure of the prepared samples. The maximum tribocatalytic decomposition of Methylene Blue (MB) dye observed was 56 % for as-quenched sample (AQ) and 74 % for heat-treated sample (HT) after 10 h of mechanical stirring at 700 rpm and for Rhodamine B (RhB) dye the degradation achieved was 34 % and 64 % in 8 h for AQ and HT respectively. Due to their superior dye decomposition capabilities, glass-ceramic crystals hold significant promise for harnessing mechanical energy through friction in wastewater treatment processes.

Cu/Co Bimetallic Carbon Catalyst as a Highly Efficient Promoter for Reactive Dyes Degradation with PMS.

The synergistic effect between bimetallic catalysts has been confirmed as an effective method for activating persulfate (PMS). Therefore, we immobilized copper-cobalt on chitosan to prepare bimetallic carbon catalysts for PMS activation and degradation of reactive dyes. Experimental results demonstrate that the CuCo-CTs/PMS catalytic degradation system exhibits excellent degradation performance toward various types of reactive dyes (e.g., Ethyl violet, Chlortalidone, and Di chlorotriazine), with degradation rates reaching 90% within 30 min. CuCo-CTs exhibit high catalytic activity over a wide pH range of 3-11 at room temperature and under static conditions, degrading over 92% of RV5 within 60 min. ultraviolet-visible (UV-vis) spectroscopy and color changes in the dye solution confirm the effective degradation of RV5, with a degradation rate of 97.2% within 10 min. Additionally, CuCo-CTs demonstrate good stability and reusability, maintaining a degradation rate of 92.8% after eight cycles. Kinetic studies indicate that the degradation follows pseudo-first-order kinetics. Furthermore, based on the results of radical scavenging experiments, the catalytic degradation mechanism of the dye involves both radical and nonradical pathways, with 1O2 identified as the primary active species. This study provides insights and experimental evidence for the application of persulfate oxidation in the treatment of dyeing wastewater.

One-pot synthesis of NiCo-phyllosilicate supported on zeolite for enhanced degradation of antibiotic contaminants

The overuse of antibiotics currently results in the presence of various antibiotics being detected in water bodies, which poses potential risks to human health and the environment. Therefore, it is highly significant to remove antibiotics from water. In this study, we developed novel rod-like NiCo-phyllosilicate hybrid catalysts on calcined natural zeolite (NiCo@C-zeolite) via a facile one-pot process. The presence of the zeolite served as both a silicon source and a support, maintaining a high specific surface area of the NiCo@C-zeolite. Remarkably, NiCo@C-zeolite exhibited outstanding catalytic performance in antibiotic degradation under PMS activation. Within just 5 min, the degradation rate of metronidazole (MNZ) reached 96.14%, ultimately achieving a final degradation rate of 99.28%. Furthermore, we investigated the influence of catalyst dosage, PMS dosage, MNZ concentration, initial pH value, and various inorganic anions on the degradation efficiency of MNZ. The results demonstrated that NiCo@C-zeolite displayed outstanding efficacy in degrading MNZ under diverse conditions and maintained a degradation rate of 94.86% at 60 min after three consecutive cycles of degradation. Free radical quenching experiments revealed that SO•− 4 played a significant role in the presence of NiCo@C-zeolite-PMS system. These findings indicate that the novel rod-like NiCo-phyllosilicate hybrid catalysts had excellent performance in antibiotic degradation.

Salt assistant bimetallic sludge-derived porous carbon for efficient peroxymonosulfate activation

The development of cost-effective, environmentally benign, and high-performance peroxymonosulfate (PMS) activation towards wastewater treatment is still considered a challenge. In this work, the sludge-derived porous carbon loaded with bimetal oxides (DSC-FeMn) was fabricated by molten salt assistant strategy using the combination of zinc chloride, metal ions and Fe containing sludge. The obtained DSC-FeMn exhibited high catalytic activity for nearly 100 % 4-chlorophenol (4-CP) removal within 30 min with the k of 0.304 min−1, which was 1.07 and 11.94 times that of the single Fe and Mn-sludge-derived carbon (DSC-Fe, DSC-Mn), respectively. Quenching experiments, electron paramagnetic resonance tests (EPR), X-ray photoelectron spectroscopy (XPS), H2-temperature programmed reduction (H2-TPR) and electrochemical experiments proved that the radical pathway, dominated by OH and SO4−, led to the excellent degradation performance of DSC-FeMn, which was attributed to the redox cycling between Fe and Mn. This study provides a new idea for sludge resource utilization, and it deepens the understanding of the mechanism of PMS activation by the synergistic interaction between bimetal.

Spatial confinement of Co3O4 in hollow carbon sphere to boost peroxymonosulfate activation for effective degradation of organic pollutants

Herein, hollow carbon sphere (HCS) is constructed via hard template method for loading the Co3O4, and obtained catalyst (namely Co3O4/HCS) is then employed to activate peroxymonosulfate (PMS) for the removal of tetracycline (TC). Owing to high specific surface area and good conductivity of HCS, Co3O4 modified with HCS exhibits low interface resistance and fast charge transfer rate. Meanwhile, hollow structure of HCS can provide spatial confinement effect for Co3O4 and accelerate the mass transfer process between Co3O4 and PMS. As predicted, peroxy bond break of PMS over Co3O4/HCS is significantly boosted compared with pure Co3O4, so reaction system can produce more SO4•–, OH•, 1O2 and high-valent metal complexes to conduct TC degradation. Importantly, Co3O4/HCS-mediated electron transfer process between PMS and TC is also involved in TC degradation. As a result, Co3O4/HCS shows excellent performance in TC degradation, and the highest removal efficiency of TC is more than 95 % within 10 min. Benefiting from the protective effect of HCS, only a small amount of Co ion is released from Co3O4/HCS during the reaction process. Besides, Co3O4/HCS possesses good reusability and anti-interference ability. In short, current work provides a promising catalyst for PMS activation to treat wastewater containing antibiotic.

Preparation of S-C3N4/AgCdS Z-Scheme Heterojunction Photocatalyst and Its Effectively Improved Photocatalytic Performance.

In this study, S-doped graphitic carbon nitride (S-C3N4) was prepared using the high-temperature polymerization method, and then S-C3N4/AgCdS heterojunction photocatalyst was obtained using the chemical deposition method through loading Ag-doped CdS nanoparticles (AgCdS NPs) on the surface of S-C3N4. Experimental results show that the AgCdS NPs were evenly dispersed on the surface of S-C3N4, indicating that a good heterojunction structure was formed. Compared to S-C3N4, CdS, AgCdS and S-C3N4/CdS, the photocatalytic performance of S-C3N4/AgCdS has been significantly improved, and exhibits excellent photocatalytic degradation performance of Rhodamine B and methyl orange. The doping of Ag in collaboration with the construction of a Z-scheme heterojunction system promoted the effective separation and transport of the photogenerated carriers in S-C3N4/AgCdS, significantly accelerated its photocatalytic reaction process, and thus improved its photocatalytic performance.

Sunflower-inspired hydrogel evaporator with mutual reinforcement of evaporation and photodegradation for integrated water management

Solar interface photothermal evaporation is a promising strategy to ensure affordable water production. However, obtaining freshwater from wastewater containing highly concentrated volatile organic compounds (VOCs) is still a high hanker. Here, a polyvinyl alcohol (PVA)-based hydrogel evaporator was developed to mutually reinforce photothermal evaporation and photocatalytic degradation. The vertical structure promoted the rapid transfer of water molecules between the microchannels. Moreover, the solar absorption efficiency can be improved through multiple reflections. Furthermore, introducing polypyrrole (PPy) and MXene@TiO2@g-C3N4 (MTG) heterojunction can not only regulate the interaction force between the polymer network and water molecules to reduce the evaporation enthalpy, but also endow the PVA/PPy@MTG hydrogel with excellent photocatalytic degradation performance. Besides, the first principles simulation indicated that this hydrogel displayed higher binding energy for contaminants than water molecules. Therefore, it can achieve an evaporation rate of ∼3.0 kg m−2 h−1 and energy efficiency of ∼97.2 % under 1-sun, higher than the structure-disordered PVA/PPy@MTG hydrogel. In addition, it can degrade different complex components, especially for highly concentrated VOCs (100 ppm) with an efficiency of >94.2 %, exceeding most of the reported integrated evaporators. This work will pave a potential pathway to design novel evaporation for sustainable water remediation.