Dataset on carbonation and chloride-induced steel corrosion in cementitious mortars.

Machine learning (ML) has seen success in civil and structural engineering, but its application to forecasting corrosion of steel reinforcement in concrete structures is limited due to small datasets from isolated studies. Moreover, the existing corrosion dataset of reinforced concrete typically lacks sufficient and comprehensive material and environmental information that enables reliable corrosion prediction of reinforced concrete under complex corrosion scenarios. This work aims to bridge the gap by compiling and building a comprehensive corrosion dataset focusing on carbon steel in cementitious mortars. This dataset involves 46 distinct mortar mixtures with embedded steel bars. The samples first underwent accelerated corrosion testing (either by carbonation or chloride contamination), followed by investigating their corrosion behaviours under varying relative humidity (RH) conditions. Corrosion data were obtained during this period, in which all corrosion measurements were conducted in laboratory settings and the results are tabulated in spreadsheet format (.xlsx). The dataset encompasses mixture parameters, material properties, environmental parameters, and electrochemical parameters. This extensive dataset provides valuable corrosion data for training ML models to predict steel corrosion across various corrosion-related variables.

Encapsulate Co3O4 within ultrathin graphene sheets to enhance peroxymonosulfate activation by tuning surface electronic structures.

Heterojunctions composed of cobalt-based materials and carbon materials have been recognized as the efficient catalysts for peroxymonosulfate (PMS) activation to generate reactive oxygen species for the removal of environmental contaminants. However, the role of carbon materials in promoting the heterojunction systems has not been fully understood. This study synthesized a heterojunction material of graphene sheets encapsulating Co3O4 (GCO-500) through the pyrolysis of cobalt MOF and applied it to activate PMS for the removal of lomefloxacin. The results showed a high removal rate of 93.59 % with a degradation rate of k1 = 0.0156 min-1. Co3O4 clusters was encapsulated within ultrathin graphene sheets (<2 nm). DFT calculations revealed that graphene layers improve the electron transfer ability of Co3O4 and increased the d-band center of Co3O4 (-1.61 eV) that promote the adsorption of PMS on GCO-500 (-1.32 eV). In the meanwhile, organic pollutant was enriched in graphene layers with high adsorption energy (-13.08 eV), which greatly enhanced the degradation efficiency of pharmaceuticals. This study provides an effective catalyst for PMS activation and sheds light on the fundamental electronic-level understanding of cobalt-based and carbon heterojunction catalysts in PMS activation.

Molecular understanding on ultraviolet photolytic degradation of cyano liquid crystal monomers.

Cyano liquid crystal monomers (LCMs) are proposed as emerging chemical pollutants with persistent, bioaccumulative, and toxic properties. Herein, five cyano LCMs, including 4-cyano-4'-ethylbiphenyl (2CB), 4-Butyl-4'-cyanobiphenyl (4CB), 4-cyano-4'-ethoxybiphenyl (2OCB), 4-(trans-4-Ethylcyclohexyl)benzonitrile (2CHB) and 4-(trans-4-Vinylcyclohexyl)benzonitrile (2eCHB), were selected to investigate the reaction kinetics and excited state characteristic variations with their molecular structures by ultraviolet (UV) photolysis. Theoretical calculations reveal that the benzene ring, ethoxy and double bond can deeply alter the electron distribution of cyano LCMs. This will affect the exciton separation ability, excitation properties and active sites to electrophilic attack, causing the distinction in photolysis efficiency. Due to the effective charge separation during local excitation (LE) process and the property of being most susceptible to electrophilic attack by 1O2 and O2•-, 2eCHB with double bond exhibits the largest degradation rate. Conversely, the weakest exciton separation of 2OCB with ethoxy during charge transfer (CT) process limits its subsequent sensitized photolysis process. The molecular orbital and fragment contributions to holes and electrons further deepen the understanding of the excited states charge transfer. This study confirmed that the intrinsic molecular structure, chemical nature and existing sites directly defined the excitation and decomposition activity in the UV photolysis of cyano LCMs.

Enhanced Resonance for Facilitated Modulation of Large-Area Perovskite Films with Stable Photovoltaics.

Upscaling efficient and stable perovskite films is a challenging task in the industrialization of perovskite solar cells partly due to the lack of high-performance hole transport materials (HTMs), which can simultaneously promote hole transport and regulate the quality of perovskite films especially in inverted solar cells. Here, a novel HTM based on N-C = O resonance structure is designed for facilitating the modulation of the crystallization and bottom-surface defects of perovskite films. Benefiting from the resonance interconversion (N-C = O and N+ = C-O- ) in donor-resonance-donor (D-r-D) architecture and interactions with uncoordinated Pb2+ in perovskite, the resulting D-r-D HTM with two donor units exhibits not only excellent hole extraction and transport capacities, but also efficient crystallization modulation of perovskite for high-quality photovoltaic films in large area. The D-r-D HTM-based large-area (1.02 cm2 ) devices exhibit high power conversion efficiencies (PCEs) up to 21.0%. Moreover, the large-area devices have excellent photo-thermal stability, showing only a 2.6% reduction in PCE under continuous AM 1.5G light illumination at elevated temperature (≈65 °C) for over 1320 h without encapsulation.

High-Performance Photocatalytic Reduction of Nitrogen to Ammonia Driven by Oxygen Vacancy and Ferroelectric Polarization Field of SrBi4 Ti4 O15 Nanosheets.

Photo-responsive semiconductors can facilitate nitrogen activation and ammonia production, but the high recombination rate of photogenerated carriers represents a significant barrier. Ferroelectric photocatalysts show great promise in overcoming this challenge. Herein, by adopting a low-temperature hydrothermal procedure with varying concentrations of glyoxal as the reducing agent, oxygen vacancies (Vo) are effectively produced on the surface of ferroelectric SrBi4 Ti4 O15 (SBTO) nanosheets, which leads to a considerable increase in photocatalytic activity toward nitrogen fixation under simulated solar light with an ammonia production rate of 53.41 µmol g-1 h-1 , without the need of sacrificial agents or photosensitizers. This is ascribed to oxygen vacancies that markedly enhance the self-polarization and internal electric field of ferroelectric SBTO, and hence, facilitate the separation of photogenerated charge carriers and light trapping as well as N2 adsorption and activation, as compared to pristine SBTO. Consistent results are obtained in theoretical studies. Results from this study highlight the significance of surface oxygen vacancies in enhancing the performance of photocatalytic nitrogen fixation by ferroelectric catalysts.

Photocatalytic degradation of GenX in water using a new adsorptive photocatalyst.

GenX, the ammonium salt of hexafluoropropylene oxide dimer acid, has been used as a replacement for perfluorooctanoic acid. Due to its widespread uses, GenX has been detected in waters around the world amid growing concerns about its persistence and adverse health effects. As relevant regulations are rapidly evolving, new technologies are needed to cost-effectively remove and degrade GenX. In this study, we developed an adsorptive photocatalyst by depositing a small amount (3 wt.%) of bismuth (Bi) onto activated-carbon supported titanate nanotubes, Bi/TNTs@AC, and tested the material for adsorption and subsequent solid-phase photodegradation of GenX. Bi/TNTs@AC at 1 g/L was able to adsorb GenX (100 µg/L, pH 7.0) within 1 h, and then degrade 70.0% and mineralize 42.7% of pre-sorbed GenX under UV (254 nm) in 4 h. The efficient degradation also regenerated the material, allowing for repeated uses without chemical regeneration. Material characterizations revealed that the active components of Bi/TNTs@AC included activated carbon, anatase, and Bi nanoparticles with a metallic Bi core and an amorphous Bi2O3 shell. Electron paramagnetic resonance spin-trapping, UV-vis diffuse reflectance spectrometry, and photoluminescence analyses indicated the superior photoactivity of Bi/TNTs@AC was attributed to enhanced light harvesting and generation of charge carriers due to the UV-induced surface plasmon resonance effect, which was enabled by the metallic Bi nanoparticles. •OH radicals and photogenerated holes (h+) were responsible for degradation of GenX. Based on the analysis of degradation byproducts and density functional theory calculations, photocatalytic degradation of GenX started with cleavage of the carboxyl group and/or ether group by •OH, h+, and/or eaq-, and the resulting intermediates were transformed into shorter-chain fluorochemicals following the stepwise defluorination mechanism. Bi/TNTs@AC holds the potential for more cost-effective degradation of GenX and other per- and polyfluorinated alkyl substances.

Efficient ofloxacin degradation via photo-Fenton process over eco-friendly MIL-88A(Fe): Performance, degradation pathways, intermediate library establishment and toxicity evaluation.

The high-throughput production of the eco-friendly MIL-88A(Fe) was achieved under mild reaction conditions with normal pressure and temperature. The as-prepared MIL-88A(Fe) exhibited efficient photo-Fenton catalytic ofloxacin (OFL) degradation upon visible light irradiation with good stability and reusability. The OFL (20.0 mg/L) was completely degraded within 50 min under visible light with the aid of MIL-88A(Fe) (0.25 g/L) and H2O2 (1.0 mL/L) in aqueous solution (pH = 7.0). The hydroxyl radicals (·OH) are the main active species during the photo-Fenton oxidation process. Meanwhile, the degradation intermediates and the corresponding degradation pathways were identified and proposed with the aid of both ultra-high performance liquid chromatography tandem quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS) and density functional theory (DFT) calculations. Finally, the degradation product library was firstly established to identify intermediate transformation products (TPs) with their variation of concentration, and their corresponding toxicologic activities were assessed via Toxtree and T.E.S.T software as well. Finally, the MIL-88A is efficient and stable with four cycles' catalysis operations, demonstrating good potential for water treatment.

Visible light photocatalytic degradation of sulfanilamide enhanced by Mo doping of BiOBr nanoflowers.

Design of high-efficiency visible light photocatalysts is critical in the degradation of antibiotic pollutants in water, a key step towards environmental remediation. In the present study, Mo-doped BiOBr nanocomposites are prepared hydrothermally at different feed ratios, and display remarkable visible light photocatalytic activity towards the degradation of sulfanilamide, a common antibacterial drug. Among the series, the sample with 2% Mo dopants exhibits the best photocatalytic activity, with a performance 2.3 times better that of undoped BiOBr. This is attributed to Mo doping that narrows the band gap of BiOBr and enhances absorption in the visible region. Additional contributions arise from the unique materials morphology, where the highly exposed (102) crystal planes enrich the photocatalytic active sites, and facilitate the adsorption of sulfanilamide molecules and their eventual attack by free radicals. The reaction mechanism and pathways are then unraveled based on theoretical calculations of the Fukui index and liquid chromatography/mass spectrometry measurements of the reaction intermediates and products. Results from this study indicate that deliberate structural engineering based on heteroatom doping and morphological control may serve as an effective strategy in the design of highly active photocatalysts towards antibiotic degradation.

Oxygen defective titanate nanotubes induced by iron deposition for enhanced peroxymonosulfate activation and acetaminophen degradation: Mechanisms, water chemistry effects, and theoretical calculation.

The large consumption of acetaminophen (APAP) worldwide and unsatisfactory treatment efficiencies by conventional wastewater treatment processes give rise to the seeking of new technology for its effective removal. Herein, we proposed a facile one-step hydrothermal method to synthesize defective iron deposited titanate nanotubes (Fe/TNTs) for peroxymonosulfate (PMS) activation and APAP degradation. The retarded first-order reaction rate of APAP degradation by Fe/TNTs was 5.1 times higher than that of neat TNTs. Characterizations indicated iron deposition effectively induced oxygen vacancies and Ti3+, facilitating the electrical conductivity and PMS binding affinity of Fe/TNTs. Besides, oxygen vacancies could act as an electron mediator through PMS activation by iron. Moreover, the formation of Fe-O-Ti bond facilitated the synergistic redox coupling between Fe and Ti, further enhancing the PMS activation. SO4•- was the major radical, causing C-N bond cleavage and decreasing the overall toxicity. In contrast, APAP degradation by neat TNTs-PMS system mainly works through nonradical reaction. The Fe/TNTs activated PMS showed desired APAP removal under mild water chemistry conditions and good reusability. This work is expected to expand the potential application of titanate nanomaterials for PMS activation, and shed light on facile synthesis of oxygen defective materials for sulfate-radical-based advanced oxidation processes.

Highly efficient AgBr/h-MoO3 with charge separation tuning for photocatalytic degradation of trimethoprim: Mechanism insight and toxicity assessment.

A highly solar active AgBr/h-MoO3 composite was constructed by a facile precipitation method, and the charge separation tuning was achieved by photoreduction of AgBr. The photoreduced Ag0 on AgBr/h-MoO3 acted as charge transfer bridge to form Z-scheme heterostructure, while the high degree of Ag reduction converted the material into type-II heterostructure. The synthesized optimal material promoted charge separation and visible light activity due to the incorporation of highly solar active AgBr, which showed ca. 2 times activity on trimethoprim (TMP) degradation than h-MoO3. The contribution of reactive species on TMP degradation followed the order of O2- >1O2 > h+, which agree well with the proposed charge separation mechanism. The photocatalytic degradation mechanism of TMP was proposed based on the radical quenching, intermediate analysis and DFT calculation. The toxicity analysis based on QSAR calculation showed that part of the degradation intermediates are more toxic than TMP, thus sufficient mineralization are required to eliminate the potential risks of treated water. Moreover, the material showed high stability and activity after four reusing cycles, and it is applicable to treat contaminants in various water matrix. This work is expected to provide new insight into the charge separation tuning mechanism for the AgX based heterojunction, and rational design of highly efficient photocatalysts for organic contaminants degradation by solar irradiation.

A novel electrocatalytic filtration system with carbon nanotube supported nanoscale zerovalent copper toward ultrafast oxidation of organic pollutants.

In this study, we designed an integrated electrochemical filtration system for catalytic activation of peroxymonosulfate (PMS) and degradation of aqueous microcontaminants. Composites of carbon nanotube (CNT) and nanoscale zero valence copper (nZVC) were developed to serve as high-performance catalysts, electrode and filtration media simultaneously. We observed both radical and nonradical reaction pathways, which collectively contributed to the degradation of model pollutants. Congo red was completely removed via a single-pass through the nZVCCNT filter (τ <2 s) at neutral pH. The rapid kinetics of Congo red degradation were maintained across a wide pH range (from 3.0-7.0), in complicated matrixes (e.g., tap water and lake water), and for the degradation of a wide array of persistent organic contaminants. The superior activity of nZVCCNT stems from the boosted redox cycles of Cu2+/Cu+ in the presence of an external electric field. The flow-through design remarkably outperformed the conventional batch system due to the convection-enhanced mass transport. Mechanism studies suggested that the carbonyl group and electrophilic oxygen of CNT served as electron donor and electron acceptor, respectively, to activate PMS to generate •OH and 1O2via one-electron transport. The electron-deficient Cu atoms are prone to react with PMS via surface hydroxyl group to produce reactive intermediates (Cu2+-O-O-SO3-), and then 1O2 will be generated by breaking the coordination bond of the metastable intermediate. The study will provide a green strategy for the remediation of organic pollution by a highly efficient and integrated system based on catalytic oxidation, electrochemistry, and nano-filtration techniques.

Silicate-Enhanced Heterogeneous Flow-Through Electro-Fenton System Using Iron Oxides under Nanoconfinement.

Herein, a silicate-enhanced flow-through electro-Fenton system with a nanoconfined catalyst was rationally designed and demonstrated for the highly efficient, rapid, and selective degradation of antibiotic tetracycline. The key active component of this system is the Fe2O3 nanoparticle filled carbon nanotube (Fe2O3-in-CNT) filter. Under an electric field, this composite filter enabled in situ H2O2 generation, which was converted to reactive oxygen species accompanied by the redox cycling of Fe3+/Fe2+. The presence of the silicate electrolyte significantly boosted the H2O2 yield by preventing the O-O bond dissociation of the adsorbed OOH*. Compared with the surface coated Fe2O3 on the CNT (Fe2O3-out-CNT) filter, the Fe2O3-in-CNT filter demonstrated 1.65 times higher kL value toward the degradation of the antibiotic tetracycline. Electron paramagnetic resonance and radical quenching tests synergistically verified that the dominant radical species was the 1O2 or HO· in the confined Fe2O3-in-CNT or unconfined Fe2O3-out-CNT system, respectively. The flow-through configuration offered improved tetracycline degradation kinetics, which was 5.1 times higher (at flow rate of 1.5 mL min-1) than that of a conventional batch reactor. Liquid chromatography-mass spectrometry measurements and theoretical calculations suggested reduced toxicity of fragments of tetracycline formed. This study provides a novel strategy by integrating state-of-the-art material science, Fenton chemistry, and microfiltration technology for environmental remediation.

Surface modification of BiOBr/TiO2 by reduced AgBr for solar-driven PAHs degradation: Mechanism insight and application assessment.

A novel solar active AgBr/BiOBr/TiO2 catalyst was synthesized by a facile coprecipitation method for solar-driven water remediation. The synthesized material composed of flower-like TiO2 nanoparticles loaded on BiOBr nanosheets and with homogeneous surface distributed Ag/AgBr nanoparticles. The internal electric field between BiOBr/TiO2 heterojunction greatly facilitated the charge carrier migration; the introduction of narrow band gap semiconductors (AgBr and BiOBr) promoted the visible light adsorption; and the Ag/AgBr nanoparticles acted as photosensitizer to further improve the light utilization. The new material showed 7.6- and 4.0-times activity of pure TiO2 and BiOBr under solar light, and the contribution of reactive species on anthracene degradation followed the order of h+ >O2•-> •OH. The degradation mechanism and pathway were proposed based on intermediates analysis and DFT calculation. The QSAR analysis revealed that the environmental risks of contaminants were greatly reduced during the photocatalysis process but some intermediates were still toxic. The high photocatalytic activity, stability and adaptability all indicated that this new material owns great application potential for cost-effective photocatalytic remediation of persistent organic contaminants under solar light.

Insights into catalytic activation of peroxymonosulfate for carbamazepine degradation by MnO2 nanoparticles in-situ anchored titanate nanotubes: Mechanism, ecotoxicity and DFT study.

Developing efficient pharmaceuticals and personal care products (PPCPs) degradation technologies is of scientifical and practical importance to restrain their discharge into natural water environment. This study fabricated and applied a composite material of amorphous MnO2 nanoparticles in-situ anchored titanate nanotubes (AMnTi) to activate peroxymonosulfate (PMS) for efficient degradation and mineralization of carbamazepine (CBZ). The degradation pathway and toxicity evolution of CBZ during elimination were deeply evaluated through produced intermediates identification and theoretical calculations. AMnTi with a composition of (0.3MnO2)•(Na1.22H0.78Ti3O7) offered high activation efficiency of PMS, which exhibited 21- and 3-times degradation rate of CBZ compared with the pristine TNTs and MnO2, respectively. The high catalytic activity can be attributed to its unique structure, leading to a lattice shrinkage and small pores to confine the PMS molecule onto the interface. Therefore, efficient charge transfer and catalytic activation through MnOTi linkage occurred, and a MnTi cycle mediating catalytic PMS activation was found. Both hydroxyl and sulfate radicals played key roles in CBZ degradation. Theoretical calculations, i.e., density functional theory (DFT) and computational toxicity calculations, combined with intermediates identification revealed that CBZ degradation pathway was hydroxyl addition and NC cleavage. CBZ degradation in this system was also a toxicity-attenuation process.

Bifunctional Bi12O17Cl2/MIL-100(Fe) composites toward photocatalytic Cr(VI) sequestration and activation of persulfate for bisphenol A degradation.

Bifunctional Bi12O17Cl2/MIL-100(Fe) composite (BMx) was firstly constructed via facile ball-milling method. The optimal BM200 was highly efficient for Cr(VI) sequestration and activation of persulfate (PS) for bisphenol A (BPA) decomposition under white light illumination, which was much more remarkable than the pristine MIL-100(Fe) and Bi12O17Cl2, respectively. Furthermore, the photocatalytic reduction efficiency can be significantly improved via the addition of some green small organic acids (SOAs). As well, the BPA degradation can be achieved over an extensive initial pH range of 3.0-11.0. When the PS concentration increased to more than 2.0 mM, the BPA degradation efficiency decreased due to the SO4-• self-scavenging effect. It was also found that the co-existence of inorganic anions like H2PO4-, HCO3-, SO42-, Cl- and NO3- could decelerate the BPA degradation. The excellent photocatalytic Cr(VI) reduction and persulfate activation performances originated from both MIL-100(Fe) with excellent PS activation ability and Bi12O17Cl2 with a favorable band position, which not only enabled the efficient separation of charges but also accelerated the formation of SO4-• radicals. The BM200 displayed prominent stability and recyclability. More importantly, the credible degradation pathway was proposed based on UHPLC-MS analysis and DFT calculation. This research revealed that the Fe-based MOFs/bismuth-rich bismuth oxyhalides (BixOyXz, X = Cl, Br and I) composites possessed great potential in wastewater remediation.

Photo-ammonification of low molecular weight dissolved organic nitrogen by direct and indirect photolysis.

The photo-ammonification process plays a crucial role in the transformation of dissolved organic nitrogen (DON) to dissolved inorganic nitrogen (DIN). However, previous studies have primarily focused on DON biotransformation than on abiotic processes. This study investigated the photo-ammonification process of nine model low molecular weight (LMW) DON molecules (e.g., amino acids, nucleotides, and urea) under the influence of different light sources. The results showed that photo-ammonification of model DON was mainly induced by UV light, while negligible contribution by visible light was found. Depending on their molecular structures, amino acids yielded different ammonia amounts, whereas negligible photo-ammonification was observed for nucleotides and urea. As for the reactive species, OH promoted ammonia yields of all the model amino acids; 3CDOM⁎ contributed to the photo-ammonification of six amino acids; 1O2 only had a positive impact on ammonification of tryptophan, histidine, and tyrosine; and CO3- accelerated ammonia generation from histidine and methionine. In natural water samples, tryptophan, tyrosine, histidine, and methionine generated significant ammonia. OH and 1O2 were speculated as the contributing reactive species based on kinetic studies as well as significant fluorescent humic-like and tyrosine-like substances degradation in irradiated samples compared to the raw samples characterized by the EEM-PARAFAC analysis. The negative linear correlations between photo-ammonification rates and the ELUMO-EHOMO of the amino acids emphasized the importance of the role of the molecular structure. Overall, these results revealed the LMW DON photo-ammonification mechanism in sunlit surface waters and highlighted its significance in the nitrogen biogeochemical cycle as well as water quality management.

Fractal Characteristics of Corrosion-Induced Cracks in Reinforced Concrete.

Based on the fractal geometry, a quantitative index describing the development degree of the internal corrosion expansion of reinforced concrete was proposed. This approach could describe the similarity and complexity of the development of corrosion-induced cracks in concrete simultaneously. Based on this approach, the influence of cracking pattern and coarse aggregate distribution on crack distribution was investigated. This study obtained the crack distribution of reinforced concrete by using the half-soaking galvanic accelerated corrosion method. The results showed that the cracking pattern was the main factor affecting the complexity of crack distribution. For cracks with the simplest cracking pattern, the presence of coarse aggregate and its surface irregularity greatly affected their development trend.

A Mathematical Model for the Electrical Resistivity of Cement Paste at Early Ages Considering the Partially Saturated State.

For cementitious materials, electrical resistivity is often used in the study of the cement hydration process at early age, as one of the few indicators that can be continuously and non-destructively monitored. Variation characteristics of resistivity are widely reported to interact with the early-age performance of cement paste, such as hydration kinetics parameters and setting time. However, there is no reasonable mathematical model to predict the resistivity at early ages, especially within the first 24 h, due to significant changes in the porosity and degree of saturation. In this work, a mathematical model was developed by considering the partially saturated state and density change of C-S-H (calcium silicate hydrate). To verify the model, two experimental methods were chosen, including the non-contact electrical resistivity test and isothermal calorimetry test. The hydration heat and resistivity of cement paste with a water-cement ratio of 0.35 and 0.45 were continuously monitored for 3 days. In the resistivity test, embedded temperature sensors were used to monitor the internal temperature and temperature correction was treated carefully in order to obtain accurate data. The test results prove that the mathematical model can accurately predict electrical resistivity and describe the saturation state of early-age cement pastes under sealed curing.

Pre-accumulation and in-situ destruction of diclofenac by a photo-regenerable activated carbon fiber supported titanate nanotubes composite material: Intermediates, DFT calculation, and ecotoxicity.

Pharmaceuticals and personal care products (PPCPs) have been widely detected in ecosystems. However, effective water purification technologies for PPCPs degradation are lacking. In this work, an active activated carbon fiber supported titanate nanotubes (TNTs@ACF) composite was synthesized via one-step hydrothermal process, which was applied for adsorption and photocatalytic degradation of PPCPs under simulated solar light. Characterizations indicated that the successful grafting of TNTs onto ACF was achieved and surface modification occurred. Diclofenac (DCF, a model PPCPs) was rapidly adsorbed onto TNTs@ACF, and subsequently photodegraded (98.8 %) under solar light within 2 h. TNTs@ACF also performed well over a wide range of pH, and was resistant to humic acid. The good adsorption and photocatalytic activity of TNTs@ACF was attributed to the well-defined hybrid structure, enabling corporative adsorption of DCF by TNTs and ACF, and extending the light absorbance to visible region. Furthermore, the description of degradation pathway and evaluation of ecotoxicity for DCF and its intermediates/byproduct were proposed based on experimental analysis, density functional theory (DFT) calculation and quantitative structure-activity relationship (QSAR) analysis, respectively, indicating the photocatalytic degradation of DCF can offer the step-by-step de-toxicity. Our study is expected to offer new strategy as "pre-accumulation and in-situ destruction" for environmental application.

Novel CuCo2O4 Composite Spinel with a Meso-Macroporous Nanosheet Structure for Sulfate Radical Formation and Benzophenone-4 Degradation: Interface Reaction, Degradation Pathway, and DFT Calculation.

A series of CuCo2O4 composite spinels with an interconnected meso-macroporous nanosheet morphology were synthesized using the hydrothermal method and subsequent calcination treatment to activate peroxymonosulfate (PMS) for benzophenone-4 (BP-4) degradation. As-prepared CuCo2O4 composite spinels, especially CuCo-H3 prepared by adding cetyltrimethylammonium bromide, showed superior reactivity for PMS activation. In a typical reaction, BP-4 (10.0 mg/L) was almost completely degraded in 15 min by the activation of PMS (200.0 mg/L) using CuCo-H3 (100.0 mg/L), with only 9.2 µg/L cobalt leaching detected. Even after being used six times, the performance was not influenced by the lower leaching of ions and surface-absorbed intermediates. The possible interface mechanism of PMS activation by CuCo-H3 was proposed, wherein a unique interconnected meso-macroporous nanosheet structure, strong interactions between copper and cobalt, and cycling of Co(II)/Co(III) and Cu(I)/Cu(II) effectively facilitated PMS activation to generate SO4•- and •OH, which contributed to BP-4 degradation. Furthermore, combined with intermediates detected by liquid chromatography quadrupole time-of-flight mass spectrometry and density functional theory calculation results, the degradation pathway of BP-4 involving hydroxylation and C-C bond cleavage was proposed.