摘要 : CeO 2 /sludge-based biochar composites were prepared by a combination of carbonization and oxidation and applied to photocatalytic degradation of humic acid reactions. The effects of the preparation process sequence on the products were investigated from the perspectives of microscopic morphology and phase composition . The results showed that when the carbonization temperature was selected as 700 °C and the oxidation temperature was selected as 650 °C, accompanied by a certain holding time, structurally stable composites were obtained. In the composites, the biochar increased the adsorption property of the system, as well as facilitated the improvement of CeO 2 photocatalytic activity . The adsorption degradation rates of S ICO and S CIO on humic acid after 3 h of illumination were 57.92% and 82.88%, respectively, which were much better than those of pristine CeO 2 and pure sludge-based biochar. This study provided new path for the practical application of municipal sludge disposal products.

摘要 : The development of an accurate, selective, sensitive, and quantitative monitoring method for copper ion (Cu 2+ ) in water and soil is crucial for addressing environmental pollution. Herein, a photocatalytic fuel cell self-powered sensor (PFC-SPS) platform was proposed by carbon-rich carbon nitride photoanode for Cu 2+ determination. Carbon-rich carbon nitride is formed by replacing nitrogen atoms of tertiary nitrogen with carbon generated through the thermal decomposition of biomass chitosan. The carbon-rich structure enhances the π delocalization in the carbon nitride skeleton, improving the optical absorption and accelerating the transmission of charge, endowing the photoanode with high and stable output signal. The formed Cu 2+ -aptamer complex increases the surface resistance of electrode, hindering the catalytic reaction of H 2 O 2 oxidation and leading to the decrease in the output power density signal. This PFC-SPS platform detected Cu 2+ with a wide range of 1.0 ∼ 1.5 × 10 3 nM, a low limit of 0.40 nM, excellent selectivity, stability and accuracy for real river water and agricultural soil samples. It is expected that the platform can achieve low-cost and portable monitoring by a digital multimeter, and this work also proposes a strategy for detecting heavy metal ions based on the synergism of a photocatalytic fuel and self-powered platform.

摘要 : There has been significant interest in using Modified basalt fibers (MBF) based bio-carriers in biological contact oxidation reactors to enhance biological remediation while minimizing secondary pollution and carbon footprints. These MBF filaments form a unique spherical structure called "bio-nest, " which supports diverse microbial communities and facilitates various biogeochemical processes. However, impact of different structural alignments of the filaments within the bio-nest on system performance has not been fully understood. To address this question, this study investigated the variable spatial structures of MBF filaments using response surface methodology . The MBF carrier media were retrofitted in a pilot-scale bio-contact oxidation reactor (R-MBF) under multiple runs, and optimal parameters for the spatial distribution were identified. The optimal parameters were identified as 17.27 cm for horizontal spacing, 15.04 cm for vertical spacing, and 62.51 % for filling ratio at 6 h of HRT. R-MBF demonstrated successful treatment performance, achieving a total nitrogen removal rate of 0.231 kg/m 3 /d simulated by the modified Stover-Kincannon model. Denitrifying and decarboxylating bacteria, heterotrophic nitrifying-aerobic denitrifying bacteria, ammonia-oxidizing bacteria, and nitrite-oxidizing bacteria were likely involved in pollutants transformation. The findings of the study emphasize the significance of filament optimization prior to installation as it may improve the efficiency of system's performance.

摘要 : Atrazine (ATZ), as a widely used herbicide, is easy to cause water pollution and serious harm to human health because of its high mobility and long residue period. Herein, a photoelectrochemical (PEC) aptasensor based on graphitic carbon nitride (g-C 3 N 4 ) loaded by CoN nanoparticles as the electron acceptor (CoN/g-C 3 N 4 ) was proposed for sensitive detection of ATZ. CoN/g-C 3 N 4 composites were synthesized by using a straightforward hydrothermal and ammonia calcination process. CoN can act as the electron acceptor to promote the transfer of photogenerated charge on the electron donor (g-C 3 N 4 ). The strong electron-absorbing capacity and wide visible light absorption range of CoN nanoparticles are conducive to the extraction of photogenerated charge. The photocurrent response of g-C 3 N 4 under visible light irradiation was remarkably improved when CoN nanoparticles were introduced. Based on the excellent PEC performance of CoN/g-C 3 N 4, a PEC aptasensor for detecting ATZ was successfully constructed. The linear response range of the sensor to ATZ was to be from 1.0 × 10 −4 to 10 fM, and the detection limit was up to 3.3 × 10 −5 fM. This aptasensor had excellent stability, selectivity, and excellent anti-jamming capability against real water samples. In view of specific recognition and excellent sensing performance, this aptasenor can be used as a practical technology for selective and sensitive detection of ATZ in the aquatic environment.

摘要 : Supercapacitors have attracted great attention in the field of energy storage due to their advantages of high-power density, fast storage efficiency, fast discharge speed and long cycle life, etc. Electrode materials are the key factor of supercapacitor to improve their performance. As an excellent electrode material for supercapacitors, g-C3N4 with high nitrogen content, abundant active sites and good stability is favored by researchers. In this paper, the structural characteristics and energy storage mechanism of g-C3N4 based electrode materials for supercapacitor were reviewed, and the performance improvement strategies of the composites were elaborated. Finally, the application research progress of g-C3N4 based supercapacitor electrode materials was summarized. It was indicated that g-C3N4 based materials had excellent application prospects for supercapacitor use.

摘要 : Due to the poor Fenton reactivity, single-atom Mn-based materials are generally identified as one of the most promising active catalysts for oxygen reduction reaction (ORR). Regulating the electronic density and coordination environment of atomically dispersed Mn centers is an effective strategy to enhance ORR activity of Mn-based materials. By introducing Zn sites, atomically dispersed Mn centers with multitudes of coordination (including Zn/Mn–Nx and Mn–Nx moieties) can be constructed to form Mn-based ORR catalyst (Zn/Mn-NC) with dual-atom sites. Around Mn–Nx sites, the Zn atoms can effectively modulate the electronic structure and coordination state of Mn centers in Zn/Mn-NC through d–d orbital coupling. The electronic interaction between Zn and Mn sites improves ORR activity, thereby optimizing the oxygen adsorption energy of Mn sites in Zn/Mn-NC and reducing the overall energy barrier. Zn/Mn-NC displays higher ORR half-wave potential than Pt/C (0.89 V vs 0.86 V). The quasi-solid-state zinc-air battery (ZAB) with Zn/Mn-NC as the cathode displayed excellent rechargeability, recyclability, and mechanical robustness. The strategy presented regulates the electronic density and coordination environment of single-atom Mn-based ORR catalysts in quasi-solid-state ZABs.

摘要 : A two-dimensional layered CeO2/Bi2O3 composite was synthesized by microwave solvothermal method. X-ray diffraction (XRD), Raman spectroscopy, field emission scanning electron microscope (FESEM), transmission electron microscope (TEM), UV-Vis diffuse reflection spectroscopy (DRS), and X-ray photoelectron spectroscopy (XPS) were used to studied crystal structure, morphology, optical performance, elemental composition and the surface electronic state of the samples. The photocatalytic properties of the prepared samples were evaluated by photocatalytic desulfurization under visible light. When the molar ratio of Ce and Bi was 1:2, CeO2/Bi2O3 composite presented the highest photocatalytic desulfurization rate. Transient Photocurrent measurement, electrochemical impedance spectroscopy (EIS) and photoluminescence spectroscopy (PL) showed that CeO2 and Bi2O3 formed a heterojunction, which could promote the separation of photogenerated electrons and holes, improving the photocatalytic activity. Furthermore, it was found that the active species of hydroxyl radical (·OH) played an important role in the photocatalytic degradation of dibenzothiophene (DBT) based on the active species capture experiment. Finally, a plausible mechanism for the photocatalytic oxidative desulfurization of this nanocomposite was proposed.

摘要 : The CeO2/BiOI/g-C3N4 composites were synthesized by solvothermal and ultrasonic stirring method. The composition, microstructure and optical properties of the material were characterized by XRD, SEM, TEM and UV-Vis DRS. The obtained CeO2/BiOI/g-C3N4 has tighter interface structure, good light response property, uniform phase distribution and high degree of crystallization. Photocatalytic degradation experiments showed that under visible light(λ>420 nm), the photocatalytic degradation efficiency of CeO2/BiOI/g-C3N4 (Ce/Bi molar ratio was 2∶1, and g-C3N4 mass fraction was 5%) for RhB was 71%, which was 7 times that of pure CeO2 and 10 times that of pure BiOI. The sample remained high photocatalytic efficiency after four cycles, revealing its good circulatory stability. Finally, the photocatalytic mechanism of the composites was introduced. It was clear that the real active substances in the photocatalytic experiment were holes and superoxide radicals.

摘要 : Porous layered g-C3N4 was selected as base material via direct calcination method to synthesize g-C3N4/CeO2/BiOBr ternary composite photocatalytic materials with heterogeneous structure, while CeO2/BiOBr composites were introduced by ultrasonic stirring method. The composition, structure and optical properties of g-C3N4/CeO2/BiOBr were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, UV-Vis DRS and photoluminescence analysis, and so on. The results show that the g-C3N4/CeO2/BiOBr has sandwich layered stacking structure, good interface contact structure and excellent light response performance due to the uniform phase distribution and high degree of crystallization. When the molar fraction of Ce∶Bi is 1∶1 and the mass fraction of g-C3N4 is 15%, the obtained three-phase composite shows the highest photocatalytic degradation property for RhB. The degradation rate for RhB is 99%, which is 86 times that of pure CeO2 and 3 times that of pure BiOBr. In addition, the composite has good stability with the RhB degradation efficiency of 89% after four cycles.

摘要 : 4-Chlorophenol (4-CP) is one of the water pollutants with high toxicity and low biodegradability. Accurate detection against 4-CP is of great value to maintain human life. A photoelectrochemical (PEC) sensor based on three-dimensional carbon-rich carbon nitride (named 3D-CN) material was proposed for monitoring 4-CP from water environment. 3D-CN material was prepared by a low-temperature supramolecular self-assembly combined with thermal-polymerization strategy. 3D and carbon rich structure endow 3D-CN material with significantly extended π-conjugated system and enhanced charge mobility, which not only easily activates inherent π → π electronic transition, but also awakens n → π electronic transition in 3D-CN material. The n → π electronic transition can further extend the absorption band edge, results into excellent PEC performance of 3D-CN material. The constructed PEC 4-CP sensor showed excellent selectivity, stability, reproducibility, and accuracy for actual water sample detection. Furthermore, the sensor provided a wide detection range (1.6–3200 μg L –1 ) and a low limit detection (0.53 μg L –1 ). This work proposes a new idea for the development of graphitic carbon nitride (g-C 3 N 4 ) materials with high PEC performance by introducing a synergistic regulation strategy of carbon rich and 3D structure, and broadens the application of g-C 3 N 4 -based materials in the field of PEC sensors.