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Peracetic acid (PAA)-based advanced oxidation processes have garnered increasing attention for eliminating organic pollutants in wastewater treatment.

Schematic diagram of the photocatalytic reduction mechanism for the PAM40 system.

Understanding how nanomaterials interact with cell membranes has important implications for ecotoxicology and human health. Here, we investigated the interactions between graphitic carbon nitride (g-C

Our paper builds the model on the basis of past literatures to express the relationship between the both height and depth of Global Value Added Chains(GVCs) and the domestic value added in exports (the DVAR in exports) of Chinese heterogeneous enterprises. The World Input-Output table (WIOD) is used to measure the industry upstream degree, which is combined with the Chinese Customs database in order to achieve the indicator of the GVCs. What’s our marginal innovation is that this paper defines the height of the enterprises’ Global Value Chains(GVCs) by the distance from the export upstream degree to the import downstream degree, extending from the industrial level to the enterprise level. The research shows that the higher position embedded in the GVCs, the more an enterprise can promote the DVAR in exports. The closer the enterprise is to the world's forefront division of labor, and the deeper it is embedded in GVCs, the more it can promote the DVAR in exports. Moreover, the higher import quality, the larger import scale and the more import downstream degree, the more the DVAR in exports will decrease. Comparing with general enterprises, processing enterprises have greater import downstream degree leading to the reduction in independent R&D and key components, so improving the position of GVCs cannot significantly improve the DVAR in exports. Although high-tech enterprises rely heavily on imports of core technology and key components with greater import downstream degree , they can improve the DVAR in exports through improving the height of GVCs. From the mechanism test, we can know that improving the height of GVCs can indirectly promote the DVAR in exports by improving the total factors productivity(TFP), reducing the import scale of intermediate goods and low-end manufacturing industry agglomeration. JEL Classification: E24, F16, L16.

A novel Z-scheme heterojunction photocatalyst Bi-BOC/BO-OVs was successfully prepared. OVs and metal Bi enhanced light response and separation of photoinduced carriers. Thus, catalyst showed superior catalytic activity in simulated water matrices.

This research provides a feasible strategy for the development and application of a novel nanosized photocatalyst and an innovative approach for the treatment of freshwater aquaculture wastewater.

Carbon dots can be efficiently degraded in UV, O3, and chlorine-based disinfection processes.

Effective photoexcitation and carrier migration are the essential aspects to strengthen semiconductor-engaged redox reaction. Herein, a three-dimensional thin-wall hollow porous cystic-like g-C

Z-scheme heterojunction-based photocatalysts typically have robust removal efficiencies for water contaminants. Herein, we employed p-type PhCsub2/subCu and n-type UiO-66-NHsub2/subto develop a direct Z-scheme UiO-66-NHsub2/sub/PhCsub2/subCu photocatalyst with an ultrahigh redox potential for Cr(VI) photoreduction and norfloxacin (NOR) photodegradation. Moreover, UV-vis diffuse reflectance, photoelectrochemical measurements, photoluminescence (PL) spectra and electron spin resonance (ESR) technique revealed that the UiO-66-NHsub2/sub/PhCsub2/subCu composite boosted light capturing capacities to promote photocatalytic efficiencies. Strikingly, the optimized UiO-66-NHsub2/sub/PhCsub2/subCu50 wt% rapidly reduced Cr(VI) (96.2%, 15 min) and degraded NOR (97.9%, 60 min) under low-power blue LED light. In addition, the UiO-66-NHsub2/sub/PhCsub2/subCu photocatalyst also exhibited favorable mineralization capacity (78.4%, 120 min). Benefitting from the enhanced interfacial electron transfer and ultrahigh redox potential of the Z-scheme heterojunction, the UiO-66-NHsub2/sub/PhCsub2/subCu photocatalyst greatly enhanced the separation efficacies of photogenerated carriers. This resulting abundance of active species (e.g., esup-/sup, hsup+/sup, Osub2/subsup•-/sup, and •OH) were generated to photo-reduce Cr(VI) and photo-oxidize NOR. Base on the identified intermediates, four degradation pathways of NOR were proposed. Finally, the Z-scheme mechanism were systematically confirmed through X-ray photoelectron spectroscopy (XPS), ESR, cyclic voltammetry (CV) tests, and photodeposition techniques.

The progress of high-efficiency photocatalysts and the suppression of photoinduced charge recombination remain the primary goals for practical applications. In this study, we demonstrate the convenient synthesis of graphite carbon nitride nanobelts (CNNB) for the enhanced photocatalytic degradation of organic contaminants through peroxydisulfate (PDS) activation. In operation, the PDS serves as an electron acceptor, whereas the organic pollutants acts as hole catchers, thus achieving an external dual transmission mechanism. Consequently, the CNNB/PDS system shows outstanding photocatalytic performance for the removal of sulfamethazine (SMT) under blue-LED light irradiation, which was ∼17- and ∼5 times more efficient than pristine g-C3N4/PDS and CNNB, respectively. Furthermore, a potential SMT degradation pathway was deduced based on the detection of degradation intermediates and theoretical calculations. Finally, reactions looking at several influencing factors indicated that the CNNB/PDS system could be used far more productively for the removal of SMT under ambient aqueous conditions. Hence, this synergistic external dual transmission mechanism process might serve as a promising technology for the removal of organic pollutants.

Although photochromic and photocatalytic performance are the most significant features of WO3, the effects of photochromism on photocatalytic activities have not been investigated further. Herein, a novel gear-shaped WO3, with high coloration efficiency, fast reversibility, and remarkable photocatalytic performance was successfully prepared via a facile hydrothermal method. The influence of photochromic effects on its photocatalytic properties was evaluated under visible light irradiation. The results showed that the yellow WO3 sample exhibited higher photocatalytic efficiencies toward tetracycline hydrochloride (TCH), oxytetracycline (OTC), rhodamine B (RhB), and ciprofloxacin (CIP) (94.3%, 87.9%, 76%, and 68.6%, respectively, in 60 min). Further research found that the redox conversion between W6+ and W5+ played a key role in separating e−/h+ pairs. Importantly, the rapid and reversible conversion between W6+ and W5+ could be realized through light radiation or H2O2 treatment. Therefore, the gear-shaped WO3 possessed tunable and sustainable photocatalytic properties and maintained a high level of activity after recycling ten times under visible light irradiation. This work provides new insights into practical WO3 applications for environmental remediation based on photochromic regulation.

Graphitic carbon nitride (g-C

Extensively used bisphenol A (BPA) in industry aggravates the pollution of water environment. Thus, we are committed to developing an efficient adsorbent to remove BPA, exploring the adsorption performance and mechanism. Here, a novel nitrogen-containing covalent organic framework, named PyTTA-Dva-COF as an effective adsorbent for removing BPA from aqueous solutions was prepared by a simple solvent-thermal method. PyTTA-Dva-COF exhibited uniform nanofibrous structure, abundant and robust C=N functional groups, as well as high chemical stability. The saturated adsorption capacity is 285 mg/g, and the adsorption process conforms to Langmuir isotherm model. The kinetic data conforms to the pseudo-second-order kinetic model, and the thermodynamic parameters, ∆G°

The low separation rate of electron-hole pairs in single-component photocatalysts severely limits their applications for wastewater treatment. For this study, SnO2/BiOCOOH photocatalysts in flower-like microspheres were controllably synthesized via a one-step hydrothermal method and were characterized by various advanced techniques. These SnO2/BiOCOOH nanocomposites demonstrated excellent photocatalytic activities for the degradation of rhodamine B (RhB), titan yellow, and levofloxacin hydrochloride (LVF). Specifically, 98.5% of RhB, 80% of titan yellow, and 85% of LVF were degraded under 5 W LED (λ = 365 nm) light irradiation within 30, 40, and 60 min, respectively. Radical trapping experiments and electron spin resonance results indicated that h+ was the dominant active radical, whereas ·O2- and ·OH played an auxiliary role in the photocatalytic system. Subsequently, a potential photocatalytic mechanism was proposed based on the experimental results.

As one of the most toxic heavy metal ions, lead pollution has become an urgent problem. Here, a cubic crystal nanoparticle (Prussian blue analogue, PBA), referred to as potassium manganese ferrocyanide (KMFC) was synthesized and used as a highly-effective sorbent for removing Pb(II) from aqueous solution. KMFC is a mesoporous material that has excellent ion exchange properties, which was confirmed by a series of characterizations. This paper investigated the adsorptive attributes of KMFC for lead ions in aqueous solution. The influences of temperature, contact time and pH on adsorption were studied in batch experiments. The KMFC possessed a robust adsorption capacity for resident lead ions in aqueous solution, which attained 1075.27 mg g−1 at room temperature (25 °C), based on the Langmuir model, which was far higher than any previously reported values. The adsorption process was well fitted to a pseudo-second-order kinetic model, as well as Langmuir and Temkin isotherm models, and was endothermic and spontaneous on the basis of thermodynamic analysis. The adsorption of Pb(II) on the surface of KMFC started with electrostatic attraction, due to the electronegativity of KMFC. Further, ion exchange was the dominant mechanism in this adsorption process, which was confirmed by FTIR, XPS, and other supplementary experiments. The good chemisorption (K+ exchange) properties of KMFC suggested that it likely has excellent prospects in applications for heavy metal ions adsorption. This study not only provided a new perspective for the design and development of heavy metal sorbents but provided a deep insight into the mechanism of adsorption of heavy metal ions by PBA.

The adsorbents for water treatment and purification are commonly not recyclable because of the lack of a reagent-less "switch" to readily release the adsorbed compounds. Herein, the interface of Bi2O2CO3 (BOC) nanosheets is designed, synthesized, and modified with citric acid, namely, modified Bi2O2CO3 (m-BOC). The m-BOC is able to selectively adsorb methylene blue (MB) in the dark and the adsorbed MB could be released in the light from m-BOC without the addition of any chemicals. The adsorption mechanism is attributed to the electrostatic attraction between positively charged MB and the negatively charged surface of m-BOC. In contrast, the desorption of MB has resulted from the photo-induced charge redistribution on the surface of m-BOC, which unlocks the coordination bond between m-BOC and the carboxylic group. As a result, BOC is recycled. Such a mechanism was verified by both experimental investigation and DFT calculation. This work provides a promising interfacial engineering strategy for the remediation of dye-polluted water and smart separation in chemical engineering.

Tartaric acid (TA) is an important component of plant rhizosphere secretion, having a certain influence on the adsorption and desorption behavior of heavy metals in soil. Humin could serve as an environmentally compatible passivator of heavy metal in soil. The aims of this study were to simulate the adsorption of Pb (II) via humin in a soil solution, explore the effects of TA on the adsorption of Pb (II) by humin and elucidate the mechanism of its influence. The results indicated that the adsorption of Pb (II) on the surface of humin within and without TA was consistent with the Langmuir isotherm equation and the pseudo-secondary kinetic model (R2 > 0.99). The effect of TA on adsorption was related to the concentration of TA. With the increasing of TA concentration, the adsorption of Pb (II) by humin showed a peak change and the adsorption amount reached the maximum with 0.5 mmol L−1 humin, is 192.31 mg L−1 with 0.1 mmol TA. Basing on adsorption experiments and characterization of FTIR, SEM, EDX and XPS. It revealed that the oxygenated groups of TA can be combined with humin by hydrogen bonding, in the low concentration TA (less than 0.5 mmol L−1), which is equivalent to an increment of the carboxyl group on the surface of humin, thus adsorption amount was increased. The increasing of the concentration of TA led to an increment of free TA in the solution, which would complex with the lead ions in the solution, and indirectly reduce the amount of Pb(II) adsorption on the humin.

Oxygen vacancy was considered to act as electron scavengers, delaying electron-hole pair recombination for their critical impacts on the electronic-band structural modulation and optical absorption of a semiconductor. However, the generation and stabilization of oxygen vacancies (Vo) remains a considerable challenge. Herein, a N-doped carbon dots/Vo-rich TiO2 nanowire array (NCDs/TiO2 NA-Vo) photoelectrode with a stable oxygen vacancy layer in TiO2 energy band was constructed successfully by doping with NCDs. This optimized NCDs/TiO2 NA-Vo photoelectrode exhibited high activity and durability with a degradation reaction constant that was ∼ two and three fold higher than that of TiO2 NA-Vo and TiO2 NA electrodes, respectively, and maintained a high degradation efficiency after eight consecutive degradation cycles. Moreover, the NCDs/TiO2 NA-Vo photoelectrode demonstrated a photocurrent density of 0.56 mA cm−2, which was more than three times that of TiO2 NA electrode. These excellent visible light-driven photoelectrocatalysis (PEC) activities could be attributed to the stabilized and regulated oxygen vacancy layer induced by NCDs, which further accelerated the interfacial charge separation to generate more free radicals (e.g., OH, O2 −, and 1O2) confirmed by electron-spin resonance (ESR) and Photoluminescence Spectra (PL). Our work provides an effective strategy to regulate the defected TiO2 electrodes in the applications of visible light-driven wastewater treatment.

Sulfonamides (SAs) have been of ecotoxicological concern for ambient ecosystems due to their widespread application in the veterinary industry. Herein, we developed a powerful advanced oxidation peracetic acid (PAA) activation process for the remediation of SAs by Co

Development of economic and efficient absorbent for the simultaneous removal of antibiotics and heavy metals is needed. In this study, a three-dimensional porous ultrathin g-C

Herein, supporting g-C

The advanced oxidation processes (AOPs) was regarded as one of the effective strategies for the degradation of organic pollutant. Herein, anovel Z-scheme type MoO3/g-C3N4 composite photocatalyst synergize with peroxydisulfate (PDS) to enhanced photocatalytic activity. Systematic studies indicated that the synergistic MoO3/g-C3N4/PDS photocatalyticsystem exhibited significantly enhanced photocatalytic activity for the degradation of ofloxacin (OFLX) in contrast to MoO3/g-C3N4 and pure g-C3N4. A 94.4% removal efficiency could be accomplished with 0.6 g/L catalyst and 5 mM peroxydisulfate (PDS) under visible light within 120 min.The enhanced photocatalytic performance of MoO3/g-C3N4/PDS could be attributed to the capture of the photoinduced electrons of PDS as well as the generation of SO4•− which can oxidize water to generate •OH. Quenching experiments revealed that O2•− and h+were the dominant active species involved in the MoO3/g-C3N4/PDS system under visible light irradiation. Degradation pathways of OFLX were then proposed based on the identification of intermediates. Reactions in inorganic anions aqueous solutions showed that MoO3/g-C3N4/PDS system provided a superior approach for the remediation of OFLX from aqueous solutions.

Non-metal doping has been frequently used in g-C3N4 (CN) as a feasible and economical technique for maintaining its metal-free properties, while improving its photocatalytic performance. In this study, a novel phosphorus and oxygen co-doped graphitic carbon nitride (POCN) was successfully synthesized through a one-step thermal polymerization method and exhibited remarkable photocatalytic activity for the photocatalytic degradation of fluoroquinolones (FQs). The degradation rate of enrofloxacin (ENFX) was 6.2 times higher than that of CN. Based on the results of X-ray photoelectron spectroscopy (XPS) and nuclear magnetic resonance spectroscopy (NMR), P atoms replaced the corner and bay carbon sites, whereas O atoms replaced the nitrogen sites in the g-C3N4 framework. The improvement of the photocatalytic effect of POCN0.01 was attributed to its narrow bandgap, effective charge separation and enhanced specific surface area. This is the first report to describe the use of phosphorus doping to promote the generation of reactive oxygen species (ROS). ROS scavenging tests revealed that O2 − was the primary active species during the degradation of ENFX. Furthermore, pathways for the degradation of ENFX were proposed via the detection of intermediate products via HRAM LC–MS/MS and the prediction of active sites using the Fukui function.

Increasing attention has been attracted in developing new technologies to remove chlorofene (CF) and dichlorofene (DCF), which were active agents in antimicrobials for general cleaning and disinfecting. This study investigated the significant influences of bicarbonate (HCO3−) on the degradation of CF and DCF in the Cu(II)-mediated Fenton-like system Cu2+/H2O2. Our results indicate that HCO3− may play a dual role to act 1) as a ligand to stabilize Cu(II), forming soluble [CuII(HCO3−)(S)]+ species to catalyze H2O2 producing hydroxyl radical ( OH) and superoxide ion (O2− ) and 2) as a OH scavenger. Furthermore, the reaction kinetics, mechanisms, and intermediates of CF and DCF were assessed. The apparent rate constants of CF and DCF were enhanced by a factor of 8.5 and 5.5, respectively, in the presence of HCO3− at the optimized concentration of 4 mM. Based on the intermediate identification and frontier electron densities (FEDs) calculations, the associated reaction pathways were tentatively proposed, including C–C scission, single or multiple hydroxylation, and coupling reaction. In addition, significant reduction in the aquatic toxicity of CF and DCF was observed after treatment with Cu2+/H2O2–HCO3- system, evaluated by Ecological Structure Activity Relationships (ECOSAR) program. These findings provide new insights into Cu(II)-mediated reactions to better understand the environmental fate of organic contaminants in carbonate-rich waters.

The adsorption behavior and mechanism of Cr(VI) on different acid-modified UiO-66s (Form-UiO-66 and Ac-UiO-66) were systematically investigated for the first time through a series of characterizations, and theoretical calculations of batch experiments. The characterization results demonstrate that acid-modified UiO-66 exhibited a larger specific surface area than did unmodified UiO-66. In addition, since the regulator (formic acid) of Form-UiO-66 was the stronger competition, the specific surface area of Form-UiO-66 (1138 m2 g−1) was larger than that of Ac-UiO-66 (915 m2 g−1). Under optimal experimental conditions, the maximum adsorption capacity of Cr(VI) was 243.9 mg g−1 on Form-UiO-66, and 151.52 mg g−1 on Ac-UiO-66, which was far higher than on the reported unmodified UiO-66 (36.4 mg g−1). The results of pH testing, zeta potential, and X-ray photoelectron spectroscopy analysis indicate that Cr(VI) ions were fixed to adsorbent surfaces via electrostatic adsorption. Acid-modified UiO-66 increased the surface active site via the increase in its specific surface area to enhance adsorption capacity of Cr(VI). These results indicated that both the surface charge and specific surface area of the adsorbent primarily determined the Cr(VI) adsorption capacity. Acid modified UiO-66 exhibited enhanced adsorption capacity, stability, and regeneration, compared to traditional adsorbents, and these results provide new insights into adsorption by MOFs.