H*ads dynamics engineering via bimetallic Pd-Cu@MXene catalyst for enhanced electrocatalytic hydrodechlorination.

Electrocatalytic hydrodechlorination (EHDC) is a promising approach to safely remove halogenated emerging contaminants (HECs) pollutants. However, sluggish production dynamics of adsorbed atomic H (H*ads) limit the applicability of this green process. In this study, bimetallic Pd-Cu@MXene catalysts were synthesized to achieve highly efficient removal of HECs. The alloy electrode (Pd-Cu@MX/CC) exhibited better EHDC performance in comparison to Pd@MX/CC electrode, resulting in diclofenac degradation efficiency of 93.3 ± 0.1%. The characterization analysis revealed that the Pd0/PdII ratio decreased by forming bimetallic Pd-Cu alloy. Density functional theory calculations further demonstrated the electronic configuration modulation of the Pd-Cu@MXene catalysts, optimizing binging energies for H* and thereby facilitating H*ads production and tuning the reduction capability of H*ads. Noteably, the amounts and reduction potential of H*ads for Pd-Cu@MXene catalysts were 1.5 times higher and 0.37 eV lower than those observed for the mono Pd electrode. Hence, the introduction of Cu into the Pd catalyst optimized the dynamics of H*ads production, thereby conferring significant advantages to EHDC reactions. This augmentation was underscored by the successful application of the alloy catalysts supported by MXene in EHDC experiments involving other HECs, which represented a new paradigm for EHDC for efficient recalcitrant pollutant removal by H*ads.

Projecting the impact of climate change and elevated CO2 concentration on rice irrigation water requirement in China.

Climate change and elevated CO2 concentrations significantly affect rice growth and water consumption. Understanding the specific impacts of climate change and elevated CO2 concentrations on rice physiological phenology, crop water demand (ETC), and irrigation water requirement (IR) is of great significance for the sustainable utilization of water resources and food security. This is particularly true in China, the world's largest rice producer. In this study, with the help of two rice phenological models, the modified Penman-Monteith equation, and the paddy water balance model, we project the changes in rice phenological period, ETC, and IR in four main rice-producing regions of China in the period 2015-2100 based on the 11 GCM outputs. The results show that the rice growing period is shortened in most rice-producing regions, except for the parts of the middle and lower reaches of the Yangtze River. Meanwhile, the trend of ETC and IR of rice varies slightly among regions in the future scenario, with almost all regions decreasing yearly except for the middle and lower reaches of the Yangtze River, where the trend is increasing. The progressively increasing atmospheric CO2 concentration has a "fertilization effect" on the crop, which can reduce the water requirements of rice. In the SSP585 scenario, the " CO2 fertilization effect" can reduce up to 8.87 × 108 m3 of ETC and 6.94 × 108 m3 of IR in the middle and lower reaches of the Yangtze River in the period of 2090s. This study provides beneficial references to understand the response of rice ETC and IR to future climate change and CO2 concentration elevation in China and highlights that the simulation in terms of crop irrigation must account for the "CO2 fertilization effect".

Separation of nutrients and acetate from sewage sludge fermentation liquid in flow-electrode capacitive deionization system: Competitive mechanisms of ions and influence of activated carbon.

Effective separation of volatile fatty acids (VFAs), ammonia (NH4+-N) and reactive phosphorous (RP) generated from anaerobic fermentation liquid is critically important for efficient resource recovery. Flow-electrode capacitive deionization (FCDI) is proven to be capable of efficient removal of ions, environmentally friendly and cost-effective in operation. The performances of FCDI system in the separation of NH4+-N, RP, and acetate and mechanism of pHs and activated carbon on their performances were investigated. Results showed that a pH of 5.0 promoted the removal of NH4+-N (53.1 %) and RP (39.5 %), and 72.0 % of acetate was retained in the solution, which revealed that removal of NH4+-N and RP, and retention of acetate were evidently affected by speciation of ions. Furthermore, the recovery of NH4+-N and RP was undermined by the adsorption of ions on activated carbon. This study provides a novel insight of ion selective mechanism during the operation of the FCDI system.

Localizing the position of the Segond fracture bed under CT measurements to determine the functional tibial insertion of an anterolateral ligament.

Background: Many studies have confirmed the existence of ligament structures in the anterolateral region of the knee that maintain rotational stability of the knee joint, namely, the anterolateral ligament (ALL). Most scholars believe that knee joint reconstruction should be considered during revision surgery and a high level of pivot displacement test (stage 2 or 3). During ALL reconstruction, the choice of ligament reconstruction sites affects the success rate and prognosis of the operation. Therefore, the choice of ligament reconstruction sites is particularly important. There is little research on the lateral ALL tibia insertion point, and most clinicians use the midpoint Gerdy's tubercle and fibular head as insertion points. However, the reconstruction effect is not ideal. Objective: This study aims to measure the position of the Segond fracture bed on CT images to determine the ALL position of the tibia. Method: To determine the position of the Segond fracture bone bed, the CT AM Volume Share 2 system was used to manually measure the position of bone fragments in 23 Segond fracture patients. Using the highest point of Gerdy's tubercle in the CT axial slices and the outermost point of the fibular head in the CT axial slices as reference points, the direction and angle of the CT slices were adjusted to ensure that the highest point of the Gerdy tubercle, the outermost point of the fibular head, and the center of Segond fracture bed were in the same sagittal slice. A CT sagittal slice measures the vertical distance from the center of the Segond fracture bed to the Gerdy-fibular line segment (G-F line segment), which is the line connecting the highest point of the segment to the outermost point of the fibula. The distance from the vertical point at the center of the Segond fracture bed of the G-F line to the highest point of the Gerdy tubercle was measured. All measurements were performed using the same measurement standard and were expressed as a percentage of the length of the G-F line. The measured results were statistically analyzed using SPSS 25.0 descriptive statistical research methods. Results: The average length of the G-F segment measured on CT images was 39.6 ± 2.0 mm, and the average vertical length from the center of the Segond fracture bed to the G-F segment was 13.1 ± 1.1 mm, accounting for 33.2% ± 2.1% of the length of the G-F segment. The length from the vertical point of the fracture bed on the G-F line segment to the highest point of the Gerdy tubercle was 14.7 ± 1.3 mm, accounting for 37.1% ± 2.9% of the length of the G-F segment. Conclusion: Through the study of the CT measurement of the Segond fracture location, we obtained the location of the functional tibial insertion of ALL, which is different from the anatomical insertion of ALL and is more inclined to the Gerdy tubercle and above, which has reference value for the treatment of recovering the function of anterolateral ligament after reconstruction.

Grafting Polymerization of Long-Chain Hydrophobic Acrylic Monomer onto Lignin and Its Application in Poly(Lactic Acid)-Based Wholly Green UV Barrier Composite Films.

The development of low-cost and high-performance bio-based composites derived from forestry waste lignin and polylactic acid has emerged as a topic of central attention. However, the weak compatibility between lignin and polylactic acid often resulted in high brittleness of the composites. Graft copolymerization is not only the most effective way to modify lignin but also can significantly improve the compatibility of lignin and polylactic acid. In this study, bio-based monomer lauryl methacrylate was grafted onto lignin by feasible radical polymerization to prepare lignin graft copolymers with excellent thermal stability and hydrophobicity, which are expected to improve the compatibility with polylactic acid. Wholly bio-based composites were prepared by compounding this graft copolymer with polylactic acid. The results showed that the crystallization ability of the composite was improved, and the highest crystallinity was increased from 6.42% to 17.46%. With addition of LG-g-PLMA lower than 9%, the thermal stability of the composites was slightly improved. At 5% copolymer addition, the elongation at break and tensile toughness of the composites increased by 42% and 36%, respectively. Observation of the frozen fracture surface of the composite by SEM found that wire drawing and ductile deformation appeared when a small amount of LG-g-PLMA was added. The thus prepared composites also showed excellent UV barrier properties. This approach provides a new idea for the high-value application of lignin.

Atomic hydrogen-mediated enhanced electrocatalytic hydrodehalogenation on Pd@MXene electrodes.

In this study, a Pd@MXene catalyst was synthesized to enhance the electrocatalytic hydrodehalogenation (ECH) of emerging halogenated organic pollutants (HOPs) by improving the dispersibility, catalytic activity, and stability of palladium (Pd). The average size of Pd nanoparticles (NPs) was reduced to 3.62 ± 0.34 nm with a more intensive peak of Pd (111), which facilitated atomic hydrogen (H*) production. The Pd@MX/CC electrode demonstrated superior ECH activity for diclofenac (DCF) degradation, with a reaction rate constant (kobs) 2.48 times higher than that of Pd/CC (without MXene). The satisfactory ECH performance of Pd@MX/CC remained consistent within a wide range of initial DCF concentrations (5-100 mg/L), and no significant ECH attenuation was observed even after up to 10 batches. Furthermore, the high activity of Pd@MX/CC was also observed in the ECH of other halogenated organic pollutants (levofloxacin, tetrabromobisphenol A, and diatrizoate). Density functional theory (DFT) calculations revealed that electronic configuration modulation of the Pd@MXene catalyst optimized binging energies to H* , DCF, and dechlorinated products, thereby enhancing the ECH efficiency of DCF.

Polylactic Acid/Lignin Composites: A Review.

With the gradual depletion of petroleum resources and the increasing global awareness of environmental protection, biodegradable plastics are receiving more and more attention as a green substitute for traditional petroleum-based plastics. Poly (lactic acid) is considered to be the most promising biodegradable material because of its excellent biodegradability, biocompatibility, and good processability. However, the brittleness and high cost limit its application in more fields. Lignin, as the second largest renewable biopolymer in nature after cellulose, is not only rich in reserves and low in cost, but it also has an excellent UV barrier, antioxidant activity, and rigidity. The molecular structure of lignin contains a large number of functional groups, which are easy to endow with new functions by chemical modification. Currently, lignin is mostly treated as waste in industry, and the value-added utilization is insufficient. The combination of lignin and poly (lactic acid) can on the one hand solve the problems of the high cost of PLA and less efficient utilization of lignin; on the other hand, the utilization of lignocellulosic biomass in compounding with biodegradable synthetic polymers is expected to afford high-performance wholly green polymer composites. This mini-review summarizes the latest research achievements of poly (lactic acid)/lignin composites. Emphasis was put on the influence of lignin on the mechanical properties of its composite with poly (lactic acid), as well as the compatibility of the two components. Future research on these green composites is also prospected.

Enhancing Hydrophobicity and Oxygen Barrier of Xylan/PVOH Composite Film by 1,2,3,4-Butane Tetracarboxylic Acid Crosslinking.

Hemicellulose has potential advantages in food packaging because of its abundant reserves, degradability and regeneration. However, compared with fossil-derived plastic films, hemicellulose-based films show inferior hydrophobicity and barrier properties because of their low degree of polymerization and strong hydrophilicity. Focusing on such issues, this work covers the modification of a xylan/polyvinyl alcohol (PVOH) film using 1,2,3,4-butane tetracarboxylic acid (BTCA) as esterifying agent. The thus prepared composite film was more compact owing to the esterification reaction with xylan and PVOH forming a crosslinked network structure and reducing the distance between molecular chains. The results showed that BTCA had a positive effect on the oxygen barrier, hydrophobicity and mechanical properties of the composite film. The tensile strength of the xylan/PVOH composite film with 10% BTCA content increased from 11.19 MPa to 13.99 MPa. A 20% BTCA loading resulted in an increase in the contact angle of the composite film from 87.1° to 108.2°, and a decrease in the oxygen permeability from 2.11 to 0.43 (cm3·µm)/(m2·d·kPa), corresponding to increase in the contact angle by 24% and a decrease in oxygen permeability by 80%. The overall performance enhancement indicates the potential application of such composites as food packaging.

Research Progress in Hemicellulose-Based Nanocomposite Film as Food Packaging.

As the main component of agricultural and forestry biomass, hemicellulose has the advantages of having an abundant source, biodegradability, nontoxicity and good biocompatibility. Its application in food packaging has thus become the focus of efficient utilization of biomass resources. However, due to its special molecular structure and physical and chemical characteristics, the mechanical properties and barrier properties of hemicellulose films are not sufficient, and modification for performance enhancement is still a challenge. In the field of food packaging materials preparation, modification of hemicellulose through blending with nanofibers or nanoparticles, both inorganic and organic, has attracted research attention because this approach offers the advantages of efficient improvement in the expected properties and better cost efficiency. In this paper, the composition of hemicellulose, the classification of nanofillers and the research status of hemicellulose-based nanocomposite films are reviewed. The research progress in modification of hemicellulose by using layered silicate, inorganic nanoparticles and organic nanoparticles in food packaging is described. Challenges and outlook of research in hemicellulose-based nanocomposite film in food packaging is discussed.

Evolution and prediction of drought-flood abrupt alternation events in Huang-Huai-Hai River Basin, China.

Drought-flood abrupt alternation (DFAA) as a compound natural disaster can cause severe socioeconomic loss and environmental destruction. Under climate change, the Huang-Huai-Hai River Basin has experienced evident increases in temperature and variability of precipitation. However, the study of the evolution characteristics of DFAA in the Huang-Huai-Hai River Basin is limited and the risk of exposure to DFAA events under future climatic conditions should be comprehensively assessed. In this study, the DFAA events including drought to flood (DTF) and flood to drought (FTD) events in the Yellow River Basin (YRB), Huai River Basin (HuRB), and Hai River Basin (HaRB) are identified by the long-cycle drought-flood abrupt alternation index (LDFAI) and the temporal variation and spatial distribution of the number and intensity of DFAA events from 1961 to 2020 are examined. The 24 climate model simulations of Coupled Model Intercomparison Project Phase 6 (CMIP6) are used to evaluate the variation of DFAA events based on the bias-corrected method. The results show that both DTF and FTD events occurred >10 times in most areas of the Huang-Huai-Hai River Basin from 1961 to 2020, and severe DFAA events occurred more frequently in the HaRB. The occurrence of DTF events decreased and FTD events continuously increased in the YRB, while they showed opposite trends in the HuRB and HaRB. In the future, the Huang-Huai-Hai River Basin is projected to experience more DTF events under the SSP1-2.6 and SSP2-4.5 scenarios, while more FTD events under the SSP3-7.0 and SSP5-8.5 scenarios. Most areas in the Huang-Huai-Hai River Basin are projected to be at medium or high risk of the frequency and intensity of DFAA events under different future scenarios, especially in the central part of the YRB. These findings can provide scientific reference to the formulation of management policies and mitigation strategies.

Highly stable and low-temperature-tolerant zinc ion storage enabled by carbitol electrolyte additive engineering.

Aqueous zinc (Zn)-ion energy storage system is widely regarded as a promising candidate for future electrochemical energy storage applications but suffers insufficient lifespan and limited operating temperature. To address these issues, we introduce a carbitol additive for a novel hybrid electrolyte to enhance cycling stability and temperature adaptability by optimizing the coordination structure of Zn ion. The modified electrolyte not only restrains the hydrogen evolution, but also promotes a high-orientation Zn deposition and significantly limits the Zn dendrite growth. Taking advantage of improved electrolyte properties, the Zn symmetric cells with 10 % carbitol-modified electrolyte exhibit long-term cycle stability for 5000 h at 25 °C, and 400 h at -10 °C. More notably, the carbitol-modified electrolyte endows a stable reversible capacitance for Zn ion hybrid supercapacitors to be operated at different temperatures. Our work affords a reasonable electrolyte engineering strategy to fabricate a highly stable and low-temperature-tolerant Zn ion storage system.

Effect of Biomass as Nucleating Agents on Crystallization Behavior of Polylactic Acid.

Polylactic acid (PLA) is one of the most productive biodegradable materials. Its bio-based source makes it truly carbon neutral. However, PLA is hard to crystallize as indicated by a low crystallization rate and a low crystallinity under conventional processing conditions, which limits its wider application. One of the most effective ways to enhance the crystallization ability of PLA is to add nucleating agents. In the context of increasing global environmental awareness and the decreasing reserves of traditional petroleum-based materials, biomass nucleating agents, compared with commonly used petroleum-based nucleating agents, have received widespread attention in recent years due to their abundance, biodegradability and renewability. This paper summarizes the research progress on biomass nucleating agents for regulating the crystallization behavior of polylactic acid. Examples of biomass nucleating agents include cellulose, hemicellulose, lignin, amino acid, cyclodextrins, starch, wood flour and natural plant fiber. Such green components from biomass for PLA are believed to be a promising solution for the development of a wholly green PLA-based system or composites.

Enhanced visible-light driven photocatalytic degradation of bisphenol A by tuning electronic structure of Bi/BiOBr.

Visible-light (VL) photocatalysis has been regarded as an intriguing technology for the control of persistent environmental pollutants. In this study, the novel homogeneous Co doped-Bi/BiOBr nanocomposites (CB-X) were prepared via a facile one-step hydrothermal method, featured with a uniform 0D Bi nanodots distribution on 2D Co-doped BiOBr nanosheets, and the photocatalytic performance was evaluated by decomposing the BPA as a prototype contaminant. The degradation experiment indicated that the optimal CB-2 nanocomposite exhibited the best photocatalytic activity with a 94% removal efficiency of BPA under the VL irradiation of 30 min; And the corresponding apparent rate constant (k) was as high as 0.107 min-1, which was 10.7 times greater than that of Bi/BiOBr (0.010 min-1). Benefiting from the modulation effect of Co-doping on the intrinsic electron configuration of Bi/BiOBr, the elevated VL adsorption capacity and accelerated h+/e- pairs separation rate were achieved, which were evidenced by photoluminescence (PL) spectroscopy, photo-electrochemical measurements and density functional theory (DFT) calculation. Moreover, the major reactive species in CB-X/VL system were uncovered to be •O2- and 1O2, whereas •OH and h+ presented a secondary contribution in the BPA elimination. Finally, the possible photocatalytic mechanism involved in CB-X nanocomposites and BPA degradation pathways were proposed on the basis of the various intermediates and products detected by LC-MS/MS.

Generalized Zero-Shot Learning With Multiple Graph Adaptive Generative Networks.

Generative adversarial networks (GANs) for (generalized) zero-shot learning (ZSL) aim to generate unseen image features when conditioned on unseen class embeddings, each of which corresponds to one unique category. Most existing works on GANs for ZSL generate features by merely feeding the seen image feature/class embedding (combined with random Gaussian noise) pairs into the generator/discriminator for a two-player minimax game. However, the structure consistency of the distributions among the real/fake image features, which may shift the generated features away from their real distribution to some extent, is seldom considered. In this paper, to align the weights of the generator for better structure consistency between real/fake features, we propose a novel multigraph adaptive GAN (MGA-GAN). Specifically, a Wasserstein GAN equipped with a classification loss is trained to generate discriminative features with structure consistency. MGA-GAN leverages the multigraph similarity structures between sliced seen real/fake feature samples to assist in updating the generator weights in the local feature manifold. Moreover, correlation graphs for the whole real/fake features are adopted to guarantee structure correlation in the global feature manifold. Extensive evaluations on four benchmarks demonstrate well the superiority of MGA-GAN over its state-of-the-art counterparts.

Non-radical mechanism and toxicity analysis of ß-cyclodextrin functionalized biochar catalyzing the degradation of bisphenol A and its analogs by peroxydisulfate.

Bisphenols (BPs) are distributed in worldwide as typical environmental hormones, which potentially harm the ecological environment and human health. In this study, four BPs, i.e., bisphenol A, bisphenol F, bisphenol S, and bisphenol AF, were used as prototypes to identify the intrinsic differences in degradation mechanisms correlated with the molecular structures in peroxydisulfate (PDS)-based advanced oxidation processes (AOPs). Electron transfer was the main way of modified biochar to trigger the heterogenous catalysis of PDS, which can cause the degradation of BPs. Phenolic hydroxyl groups on bisphenol pollutants were considered as possible active sites, and the existence of substituents was the main reason for the differentiation in the degradation efficiency of various bisphenols. Results of ecotoxicity prediction showed that most intermediates produced by the degradation of BPs in the ß-SB/PDS system, which was dominated by the electron transfer pathway, had a lower toxicity than the parent molecules, while the toxicity of several ring cleavage intermediates was higher. This study presents a simple modification scheme for the conversion of biochar into functional catalysts and provides insights into the mechanism of heterogeneous catalytic degradation mediated by modified biochar as well as the degradation differences of bisphenol pollutants and their potential ecotoxicity.

Wastewater post-coagulation sludge recycled as a multifunctional adsorbent via pyrolysis enhanced in carbon dioxide (CO2).

Massive wastewater post-coagulation sludge (WPCS) generated from the tertiary treatment facilities has been regarded as an environmentally burdensome waste. Herein, to take advantage of the abundant amounts of Al/Fe (hydr)oxides, the WPCS was converted into functional char via pyrolysis under CO2 and N2 atmosphere. The higher organic matter content and porous structure of WPCS than drinking water treatment sludge made it a more suitable precursor for biochar and adsorbent production. CO2 expedited the thermolysis of the organics in WPCS and the Fe (hydr)oxides in WPCS further decreased the temperature of CO2-mediated reaction. Therefore, the corresponding products outcompeted the chars in N2, achieving ∼37% higher specific surface area, stronger aromaticity and more amorphous Al and Fe contents of 201.19 ± 2.25 and 27.03 ± 0.56 mg g-1, accompanied by more loss of surface functional groups like carboxyl and hydroxyl. Accordingly, WPCS chars under CO2 showed superior performance for removing phosphate (15.58 ± 0.19 mg g-1), along with the adsorption of heavy metal (37.17 ± 1.25 mg g-1 of Pb (II)) and dye (14.45 ± 0.11 mg g-1 of methylene blue). In sum, this study proposes a win-win strategy to convert coagulation sludges into resources and a new candidate for multifunctional adsorbent production.

Degradation of Perfluorooctanoic Acid with Hydrated Electron by a Heterogeneous Catalytic System.

Hydrated electron (eaq-)-induced reduction protocols have bright prospects for the decomposition of recalcitrant organic pollutants. However, traditional eaq- production involves homogeneous sulfite photolysis, which has a pH-dependent reaction activity and might have potential secondary pollution risks. In this study, a heterogeneous UV/diamond catalytic system was proposed to decompose of a typical persistent organic pollutant, perfluorooctanoic acid (PFOA). In contrast to the rate constant of the advanced reduction process (ARP) of a UV/SO32-, the kobs of PFOA decomposition in the UV/diamond system showed only minor pH dependence, ranging from 0.01823 ± 0.0014 min-1 to 0.02208 ± 0.0013 min-1 (pH 2 to pH 11). As suggested by the electron affinity (EA) and electron configuration of the diamond catalyst, the diamond catalyst yields facile energetic photogenerated electron emission into water without a high energy barrier after photoexcitation, thus inducing eaq- production. The impact of radical scavengers, electron spin resonance (ESR), and transient absorption (TA) measurements verified the formation of eaq- in the UV/diamond system. The investigation of diamond for ejection of energetic photoelectrons into a water matrix represents a new paradigm for ARPs and would facilitate future applications of heterogeneous catalytic processes for efficient recalcitrant pollutant removal by eaq-.

In-situ pyrolysis of Taihu blue algae biomass as appealing porous carbon adsorbent for CO2 capture: Role of the intrinsic N.

An environment-friendly, cost-effective, and facile N self-doping porous carbon (NC) were prepared through in-situ pyrolysis of nitrogen abundant Taihu blue algae biomass for CO2 uptake. It was found that the CO2 sorption capacity of porous carbon prepared through carbonization at 800 °C with KOH activation (N-C-800) exhibit higher CO2 uptake capacity of 4.88 (1 bar and 0 °C) and 2.76 mmol/g (1 bar and 25 °C) respectively, with the CO2/N2 selectivity of N-C-800 attaining 39.3. Besides, the adsorption capacity of N-C-800 remained stable even after 7 repeated cycles, with a slight loss of nearly 6%. Moreover, total graphitic N (Ntg) sources from the intrinsic N in N-C-800 is not only higher than other agro-sourced porous carbon materials, but the graphitic N performed a sound correlation with the CO2 uptake capacity. Combining experiments with Density Functional Theory (DFT) calculations, higher adsorption energy of N-C-800 (-13.6 kJ/mol, comparing with -6.9 kJ/mol of N-free carbon framework) would render the efficient adsorption of CO2 molecular onto the graphitic N site. The current study not only provides a new option for the reclamation of Taihu blue algae biomass as N self-doping material, but a proof-of-concept investigation employing NC materials as an appealing candidate for CO2 capture.

Effective in-situ reduction of Cr(VI) from leather wastewater by advanced reduction process based on CO2·- with visible-light photocatalyst.

Advanced reduction process (ARP) has drawn an increasing interest as a new manner for removing oxidative pollutants in water. In this paper, we demonstrate the possibility of in-situ reduction of Cr(VI) by CO2·- produced from formate originally existing in leather wastewater by visible-light-driven ARP containing black TiO2 photocatalyst. The prepared black TiO2 with nanotube structure achieves remarkable enhanced the reduction rate of Cr(VI) as high as 96.2% (k = 0.0114 min-1) in the presence of formate, which is approximately 4.75 times than that of 56.3% (k = 0.0024 min-1) in the absence under 120 min visible-light irradiate at unadjusted pH. The results exhibit a distinct contrast with commercial TiO2 (P25). A series of control experiments are also performed, indicating that formate is able to convert the oxidative environment into a highly reductive one, and the formate concentration, black TiO2 dosage and pH may greatly impact on the Cr(VI) reduction rate. According to the electron spin resonance (ESR) measurement, CO2·- radicals can be directly verified as dominate radical in this system. Moreover, this system appears to be attractive for creating photochemical systems where in-situ production of CO2·- radicals may be realized by using formate. Then this in-situ ARP system will provide a new perspective for the Cr(VI) removing, which makes leather wastewater treatment much easier and more sustainable in the future.