查找使用阿拉丁产品的科研文献

Photocatalytic conversion of polylactic acid microplastics using CoO/g-C3N4 composite with improved formation of low-molecular-weight oxygenates

Naseer Ahmad,Muhammad Jamshed,Mansoor Ahmad,Neha,Bei Wang,Siew Ling Lee,Wei Sun

CoO/g-C 3 N 4 shows marginal improvement in PLA microplastic degradation. • CoO modification narrows the distribution of low-molecular-weight oxygenated products. • A lactate/lactic-acid-type product is tentatively identified as a key intermediate. • O 2 • ˉ is confirmed as the dominant reactive species during photocatalysis. Polylactic acid (PLA) microplastic endures in the environment despite the biodegradable nature of PLA, requiring effective methods for conversion under mild conditions. In this work, a CoO/g-C 3 N 4 composite was synthesized by a wet impregnation-calcination method and evaluated for UV-driven photocatalytic conversion of PLA microplastics. A loading-screening study identified the nominal 0.53 wt% CoO/g-C 3 N 4 composite as the best-performing composition among the tested loadings, and ICP analysis confirmed an elemental Co content of 0.4170 wt%, close to the theoretical value of 0.4168 wt%. Replicated photocatalytic tests showed apparent conversions of 14.50 ± 0.06%, 56.07 ± 0.72%, 65.46 ± 0.27%, and 69.68 ± 0.65%, after 100 min for UV only, CoO, g-C 3 N 4 , and CoO/g-C 3 N 4 , respectively. The corresponding apparent pseudo-first-order rate constant for CoO/g-C 3 N 4 was 0.01153 ± 0.00021 min −1 . The recyclability experiment showed that the catalyst retained 92.02% of its initial apparent conversion after four cycles, and ICP-MS analysis of the final-cycle filtrate showed a trace Co concentration of 0.083 μg/L. Radical-trapping and electron paramagnetic resonance analysis suggested that O 2 • ˉ was the dominant reactive species, whereas • OH and h + provided secondary contributions. Product analysis by total organic carbon, high-performance liquid chromatography, liquid chromatography-mass spectrometry, and pyrolysis-gas chromatography/mass spectrometry suggested that CoO/g-C 3 N 4 composite promoted a narrower distribution of low-molecular-weight oxygenated products compared with pristine g-C 3 N 4 . Additional LC/MS analysis using an authentic lactic acid standard and a lactic acid-spiked PLA sample supported the assignment of the m / z 89.02 product signal to lactic-acid/lactate-type species. These results indicate that CoO modification influences both the apparent conversion and the product distribution during UV-driven photocatalytic PLA transformation. Download: Download high-res image (156KB) Download: Download full-size image

S-scheme g-C3N4/Ce-MgAl-LDH heterojunction for tetracycline degradation: response surface methodology-guided optimization and mechanistic insights

Yanling Hu,Yanshu Chen,Ruitong Li,Ximan Wang,Sigen A,Yunfeng Wu,Dehui Bian,Siqi Bao

Constructed an S-scheme g-C 3 N 4 /Ce-MgAl-LDH heterojunction via hydrothermal method. • Achieved complete TC-HCl degradation in 20 min under visible light with H 2 O 2 synergy. • Identified superoxide radicals as dominant species and proposed three degradation pathways. • Revealed enhanced charge separation via Ce doping and S-scheme interfacial transfer. • Demonstrated 85.3% stability after five cycles with reduced ecotoxicity of intermediates. Antibiotic contamination, especially by tetracycline hydrochloride (TC-HCl), presents significant environmental and health challenges. In this study, a 3D flower-like g-C 3 N 4 /Ce-MgAl-LDH composite was synthesized for effective TC-HCl degradation. In situ XPS and DFT calculations confirmed that the formed S-scheme heterojunction enhances charge separation while maintaining strong redox capabilities. Response surface methodology (RSM) identified pH as the key factor influencing degradation efficiency. Under optimized conditions, the catalyst achieved complete TC-HCl removal within 20 min and a mineralization efficiency of 39.8% based on TOC analysis. Quenching experiments and EPR spectroscopy revealed superoxide radicals (·O 2 - ) as the primary reactive species. The composite also demonstrated excellent environmental adaptability, broad-spectrum activity, and cyclic stability, retaining 85.3% of its activity after five successive cycles. This work combines an advanced S-scheme photocatalyst design with RSM-guided optimization, offering a practical strategy for antibiotic wastewater treatment. Mechanism diagram of TC-HCl degradation in the CN/LDH-15%/H 2 O 2 /Vis system Download: Download high-res image (190KB) Download: Download full-size image

Construction of Z-scheme C-LaFeO3/Co-doped g-C3N4 heterojunction for synergistic photocatalysis-PMS activation in antibiotic degradation

Zuyang Huang,Lianyang Huang,Shuohai Fang,Yunchuan Yang,Meidan Lai,Xin Zhong,Changzhong Liao,Zihao Wu,Jun Liu

Advanced oxidation processes (AOPs) based on photocatalysis and peroxymonosulfate (PMS) activation hold great promise for the remediation of organic wastewater. To overcome the limitation of narrow light utilization, sluggish PMS activation, and weak synergy between photocatalysis and PMS activation, the rational integration of transition-metal-mediated PMS activation with heterostructure engineering under light provides an efficient pathway for accelerating internal electric field construction and enhancing pollutant degradation. Herein, a C-LaFeO 3 anchored Co-doped g-C 3 N 4 (C-LFO/Co-CN) catalyst was synthesized via a multi-step in situ calcination strategy. When the mass ratio of C-LFO: Co: CN was optimized to 10:1:100, the C-LFO/Co-CN catalyst exhibited optimal photo-Fenton-like synergistic performance, achieving an initial 30-minute degradation rate 5.8 times higher than that under visible light alone. It was revealed that the Co sites directly interact with PMS to form high-valent cobalt (Co(IV) = O). Furthermore, the reconstruction of the internal electric field establishes a Z -scheme heterojunction. This configuration drives the directional migration of photogenerated electrons under illumination, promoting the direct involvement of photogenerated holes from the C-LFO valence band in the degradation of NOR. The influx of photogenerated electrons in Co-CN facilitates the reduction of Co valence states, while in C-LFO, the Fe sites further participate in the formation of a Co Fe valence state cycling system under the activation of PMS. These synergistic dual-metal redox cycles ultimately promote the highly efficient degradation of NOR in the (C-LFO/Co-CN)-PMS-Vis system. This study provides new mechanistic insights and theoretical guidance for efficient photocatalysis–PMS synergistic catalysts for wastewater treatment.

Facile synthesis of Co3O4/g-C3N4 with enhanced peroxidase-like activity for colorimetric detection of glutathione and L-cysteine

Xiaoxia Hu,Xin Yang,Chunhua Wang,Tiantian Tan,Xiaojie Liu,Xiaodan Liu

Biothiols, such as glutathione (GSH) and L-cysteine (L-Cys), were essential for maintaining human physiological homeostasis, and their abnormal levels are closely associated with various diseases. Herein, a composite nanoenzyme Co3O4/g-C3N4 with significantly enhanced peroxidase-like activity was successfully synthesized by combining ZIF-67-derived Co3O4 with graphitic carbon nitride (g-C3N4). The 3,3′,5,5′-tetramethylbenzidine (TMB) could be efficiently oxidized to blue TMB (oxTMB) by Co3O4/g-C3N4 in the presence of H2O2, while biothiols (GSH and L-Cys) inhibited this catalytic reaction due to their antioxidant properties, leading to a visible color fading. Based on the mechanism, a colorimetric detection method was established for quantitative analysis of GSH and L-Cys with linear ranges of 0~30 μM for GSH and 1~30 μM for L-Cys, respectively. Moverover, a convenient smartphone-assisted sensing platform was established for detection of GSH and L-Cys benefiting from the Co3O4/g-C3N4 based colorimetric strategy. These established methods had been applied to detect GSH and L-Cys in human urine, which showed great potential for self-health monitoring.

Synergistic Enhancement of Visible-Light-Driven Photocatalytic H2O2 Production over g-C3N4/ZnCdS by Zn Vacancies and Heterointerface Engineering

Zhenyu Wang,Wei Yan,Yingcong Wei,Jing Xu,Yuee Xie,Yuanping Chen,Xiaohong Yan

Hydrogen peroxide (H2O2) is an important green oxidant, and developing efficient visible-light-driven routes for its synthesis is highly desirable. Herein, a CN/ZnV-ZCS composite photocatalyst was constructed by coupling g-C3N4(CN) with Zn-vacancy-containing ZnCdS (ZnV-ZCS) for photocatalytic H2O2production. The optimized CN/ZnV-10 delivered 44.58 mmol g−1H2O2within 60 min under 425 nm LED irradiation, outperforming pristine CN, ZCS, ZnV-ZCS, and vacancy-free CN/ZCS, with good cycling stability. Trapping and EPR results identify O2as the key electron acceptor and ·O2−as an important intermediate. Structural characterization and XPS results indicate successful Zn-vacancy introduction, intimate heterointerface formation, and interfacial electron redistribution. Combined VB-XPS, photoelectrochemical, and reactive-species analyses suggest that Zn vacancies are favorable for O2adsorption/activation, whereas the CN/ZnV-ZCS heterointerface promotes charge separation and migration. Based on the available evidence, a Z-scheme interfacial charge-transfer pathway is established in the CN/ZnV-ZCS system.

Biomimetic synthesis of C-doped g-C3N4 spinous hollow microspheres from sunflower pollen with enhanced visible-light photocatalytic performance

Wenshi Liu,Baogang Wang

Construction of ternary BiOBr/NH2-MIL-101(Fe)/g-C3N4 nanocomposite as an efficient photocatalyst for degradation of tetracycline

Zhao Xu,Guo Hongyan,Zhang Nannan,Yue Zhi,Gu Xungang

A novel dual Z-scheme BiOBr/NH 2 -MIL-101(Fe)/g-C 3 N 4 (BNG) heterojunction was constructed via a simple two-step solvothermal process. NH 2 -MIL-101(Fe) nanoparticles and BiOBr microspheres were uniformly deposited on the surface of g-C 3 N 4 . The prepared BNG exhibited significantly enhanced photocatalytic performance for tetracycline (TC) degradation compared to single catalyst. The optimized BNG-19 composite (with 19% NH 2 -MIL-101(Fe)/g-C 3 N 4 ) achieved 92.38% degradation of TC within 75 min under visible light, which was 2.47, 1.78, and 1.84 times higher than that of pure g-C 3 N 4 , NH 2 -MIL-101(Fe), and BiOBr, respectively. Moreover, the composite exhibited excellent stability with 82.4% removal efficiency after five cycles. The enhanced photocatalytic performance was attributed to the synergistic dual Z-scheme charge transfer mechanism, which was directly evidenced by in-situ irradiated XPS showing opposite directional shifts of Bi 4f (positive) and Fe 2p/N 1s (negative). This unique charge transfer pathway effectively promoted the separation of photogenerated carriers, with •OH and •O 2 ⁻ identified as the dominant reactive species. This work provides a new strategy for constructing g-C 3 N 4 -based dual Z-scheme heterostructures with direct mechanistic evidence for efficient environmental remediation.

Effects of g-C3N4 on bacterial community and tetracycline resistance genes in two typical sediments in tetracycline pollution remediation

Hu Xuemei,Chen Xiaoyong,Tang Yao,Xu Zhenggang,Zeng Yelin,Wang Yonghong,Zhao Yunlin,Wu Yaohui,Wang Guangjun

Photocatalysis, as a novel technique, has been widely used for antibiotic pollution remediation in wastewater. In the processes of degradation and removal of antibiotics, the impact of photocatalysts on microenvironment is very important but remains poorly understood. In the present study, the effect of typical photocatalyst g-C3N4 (Graphitic carbon nitride) on microbial community was investigated in two sediment types (riverbed sediment and pig-farm sediment) polluted by tetracycline (TC) in central southern China. The riverbed sediment and pig farm sediment samples were respectively exposed to g-C3N4 (25, 75, 125 mg⋅kg–1) and TC (60, 120, 180 mg⋅L–1) treatments alone or combination for 30 days, respectively. The bacterial community and antibiotic resistance genes (ARGs) of the treated sediments were analyzed by Illumina sequencing and metagenomic sequencing. Studies had shown that: TC, g-C3N4, and TC/g-C3N4 have significant effects on the changes of microbial communities and components in riverbed sediment, but they do not exist in pig farm sediment. The most alterations of microbial taxa were Acidobacteriota, Actinobacteriota, and Desulfobacterota in riverbed sediment, and Elusimicrobiota in the pig farm sediment under various treatments. Through network analysis, it was found that the distribution of microorganisms in the pig farm sediment is more complex and more stable. The addition of g-C3N4 reduced the absolute abundance of ARGs in the two examined sediments, but not significantly changed their relative abundance of ARGs. The g-C3N4 application was beneficial to the removal of TC residues and to the prevention of the generation and transmission of ARGs in sediments. Our results suggested that g-C3N4 was a suitable photocatalyst with excellent application prospect for the removal of TC residues and the control of ARGs in environment.

Sequential hydrogenation of nitroaromatics to alicyclic amines via highly-dispersed Ru–Pd nanoparticles anchored on air-exfoliated C3N4 nanosheets

Jiale Wu,Liguo Wang,Shuang Xu,Yan Cao,Ziqiang Han,Huiquan Li

Developing efficient and green catalytic systems is highly desired in the syntheses of alicyclic amines via hydrogenation of nitroaromatics. Herein, we developed Ru–Pd dual active site catalysts in which Ru and Pd species were anchored and highly dispersed on air-exfoliated carbon nitride (Ru–Pd/C3N4-air). As-prepared catalysts were employed in the hydrogenation of nitrobenzene (NB) to cyclohexylamine (CHA). Compared with single Ru or Pd based catalysts, Ru–Pd dual active site catalysts obtained a higher CHA production rate of 26.7 mol CHA mol−1 Ru·Pd h−1 at 80 °C and 3 MPa H2. The activation energy for the hydrogenation of the nitro group and benzene ring was calculated as 26.26 kJ mol−1 and 66.30 kJ mol−1, respectively. Intrinsic kinetic studies demonstrated that Pd was the dominant metal for hydrogenation of nitro group, while Ru was dominant for benzene ring. Thereinto, the corresponding non-dominant metals enhanced activation and dissociation of H2, thereby improving catalytic activity significantly. This excellent performance of Ru–Pd catalysts could be attributed to highly dispersed Ru–Nx and Pd–Nx at a nanoscale distance, which was conducive to metal-assisted hydrogenation. Stability investigation showed that the performance of Ru–Pd catalysts could be essentially maintained at a high level. Additionally, the substrate scope could be successfully extended to hydrogenation of other nitroaromatics with different substituents.

In situ loading amorphous CoSx on N-doped g-C3N4 through light assisted synthesis for enhanced photocatalytic hydrogen generation

Puhui Deng,Chuanjun Xi,Ning Chen,Hongpeng Shi,Linping Zhang,Yu Hou

Loading co-catalysts are an effective strategy to break the confinement of bulk carbon nitride in photocatalysis . Employing this strategy, N-doped g-C 3 N 4 decorated with CoS x was successfully prepared through a photochemical synthesis route. The optimum hydrogen evolution performance of N-CN-CoS x -4 was 1757 μmol g −1  h −1 under visible light irradiation . Superior interfacial carrier transfer properties and improved light absorption of N-CN-CoS x -4 could elucidate its better photocatalytic activity . This research offers a reference for the construction of high-efficiency, stable and low-priced photocatalysts .

Ru Single Atoms on One-Dimensional CF@g-C3N4 Hierarchy as Highly Stable Catalysts for Aqueous Levulinic Acid Hydrogenation

Ying Yang,Suoying Zhang,Lin Gu,Shijie Hao

Herein, we report a stable catalyst with Ru single atoms anchored on a one-dimensional carbon fiber@graphitic carbon nitride hierarchy, by assembling wet wipes composed of fiber-derived carbon fiber (CF), melamine-derived graphitic carbon nitride (g-C3N4) and RuCl3 before NaBH4 reduction. The atomically dispersed Ru species (3.0 wt%) are tightly attached via N-coordination provided by exterior g-C3N4 nanosheets, and further stabilized by the interior mesoporous CF. The obtained CF@g-C3N4–Ru SAs catalyst can be cycled six times without notable leaching of Ru or loss of GVL yield in the acidic media. This catalyst is more stable than Ru nanoparticles supported on CF@g-C3N4, as well as Ru single atoms anchored on CF and g-C3N4, and proves to be one of the most efficient metal catalysts for aqueous LA hydrogenation to γ-valerolactone (GVL). The isolated Ru atoms by strong N-coordination, and their enhanced electron/mass transfer afforded by the one-dimensional hierarchy, can be responsible for the excellent durability of CF@g-C3N4–Ru SAs under harsh reaction conditions.Keywords:Ru single atom;one-dimensional hierarchy;levulinic acid;γ-valerolactone;stability

Synthesis and Characterization of g-C3N4/Ag3PO4/TiO2/PVDF Membrane with Remarkable Self-Cleaning Properties for Rhodamine B Removal

Renguo Liu,Xue Li,Jinhui Huang,Haoliang Pang,Qiongfang Wan,Kun Luo,Ya Pang,Lingyu Wang

g-C3N4/Ag3PO4/TiO2nanocomposite materials were loaded onto a polyvinylidene fluoride (PVDF) membrane using a phase inversion method to obtain a photocatalytic flat membrane for dye removal. The morphology, structure, and photocatalytic activity of the g-C3N4/Ag3PO4/TiO2nanoparticles and composite membrane were evaluated. The g-C3N4/Ag3PO4/TiO2/PVDF membrane exhibited superior morphology, hydrophilic properties, and antifouling performance compared with the raw PVDF membrane. Four-stage filtration was performed to evaluate the self-cleaning and antifouling capacity of the g-C3N4/Ag3PO4/TiO2/PVDF membrane. Upon irradiating the composite membrane with visible light for 30 min, its irreversible fouling resistance (Rir) was low (9%), and its flux recovery rate (FRR) was high (71.0%) after five filtration cycles. The removal rate of rhodamine B (RhB) from the composite membrane under visible light irradiation reached 98.1% owing to the high photocatalytic activity of the membrane, which was superior to that of raw PVDF membrane (42.5%). A mechanism of photocatalytic composite membranes for RhB degradation was proposed. Therefore, this study is expected to broaden prospects in the field of membrane filtration technology.Keywords:g-C3N4/Ag3PO4/TiO2nanocomposite;photocatalytic membrane;self-cleaning;membrane fouling;dye