ENVIRONMENTAL RESEARCH
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2024
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IF 7.7
Shi-Wen Lv,Jialu Pan,Xiaoran Wang,Yifan Shao,Yanqing Cong,Lin Che
It is of great significance to establish an effective method for removing Cr(VI) from wastewater. Herein, Fe-doped g-C 3 N 4 (namely Fe-g–C 3 N 4 –2) was synthesized and then employed as photocatalyst to conduct the test of Cr(VI) reduction. Notably, the embedding of Fe ion in g-C 3 N 4 can offer the Fe 2+ /Fe 3+ redox couples, so reducing the interfacial resistance of charge transfer and suppressing the recombination of photogenerated electrons and holes. The impurity energy levels will form in g-C 3 N 4 after the introduction of Fe ion , thereby boosting the light absorption capacity of catalyst. Thus, Fe-g–C 3 N 4 –2 showed good performance in photocatalytic Cr(VI) reduction, and the reduction efficiency of Cr(VI) can reach 39.9% within 40 min. Different with many previous studies, current work unexpectedly found that the addition of p -benzoquinone (BQ) can promote the Cr(VI) reduction, and the reduction efficiency of Cr(VI) over Fe-g–C 3 N 4 –2 was as high as 93.2% in the presence of BQ (1.5 mM). Further analyses showed that BQ can be reduced to hydroquinone (HQ) by photogenerated electrons, and UV light can also directly induce BQ to generate HQ by using H 2 O as the hydrogen donor . The HQ with reducing ability can accelerate the Cr(VI) reduction. In short, current work shared some novel insights into photocatalytic Cr(VI) reduction in the presence of BQ. Future research should consider possible reactions between photogenerated electrons and BQ. For the UV-induced photocatalysis , the suitability of BQ as the scavenger of O 2 •‒ must be given carefully consideration.
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Environmental Science-Nano
·
2017
·Vol. 5
·期 2
·487-496
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IF 6.047
Changqing Zhu,Fuqiang Liu,Li Song,Hao Jiang,Aimin Li
Magnetic core–shell Fe3O4@polyanilines (Fe3O4@PANI) were controllably synthesized to harvest microwave (MW) energy for ultrafast Cr(VI) reduction. The nanocomposites are excellent MW acceptors due to the combination of the magnetic loss of Fe3O4 and dielectric loss of PANI. Under MW irradiation, abundant hot spots are generated on Fe3O4@PANI to accelerate the reduction of surface-bound Cr(VI). Moreover, Fe3O4@PANI is highly stable in an acidic solution and readily recoverable with an external magnet after use. The PANI shell possesses good enrichment ability for Cr(VI), creating a high Cr(VI) surface concentration which benefits the sequential reduction. Furthermore, an increase in the PANI coating amount from 24.78% to 55.15% increases the Cr(VI) adsorption capacity (qe) from 0.63 mmol g−1 to 1.68 mmol g−1, which linearly enhances the removal rate constant (k) of Cr(VI) under an MW field as k = 0.30qe − 0.03. The addition of oxalic acid as a sacrificial electron donor increases the Cr(VI) removal rate by 120.09% and protects the PANI shell from excessive oxidation by Cr(VI); this prolongs the lifetime of Fe3O4@PANI. In the presence of oxalic acid, the MW-driven Cr(VI) reduction on Fe3O4@PANI proceeds at a rate constant of 0.5773 min−1, which is much higher than that of palladium-based chemocatalysis. Moreover, Fe3O4@PANI can be in situ regenerated by MW and directly reused in the next cycle, and no efficiency loss occurs in 5 continuous runs. The mechanism study based on Cr species tracking and solid analyses indicates that a synergistic adsorption and reduction cycle proceed consecutively, contributing to the rapid Cr(VI) removal. This study demonstrates that Fe3O4@PANI is a promising alternative to utilize MW for ultrafast Cr(VI) reduction and has the advantages of time-saving and energy efficiency.
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ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2024
·Vol. 31
·期 23
·34607-34621
·
IF 0
He Haixia,Cheng Yanhui,Qiu Siwei,Sun Lei,Jin Bohua,Yuan Xiangjuan
A series of ZnO decorated reduced graphene oxide (rGO) (ZnrGO x ) with different doping ratios were synthesized by the alkaline hydrothermal method using graphene oxide (GO) and Zn(NO 3 ) 2 ·6H 2 O as precursors, and subsequently used for the adsorption study of Cr(VI) in water. The morphology, crystalline phase structure, and surface elemental properties of ZnrGO x composites were revealed by XRD, SEM, BET, FT-IR, and XPS characterizations. The results showed that ZnO nanoparticles can be clearly seen on the surface of layered rGO. Meanwhile, as the doping rate increased, the C = C double bonds were broken and more carboxylic acid groups formed in ZnrGO x . In addition, the ZnrGO 0.1 composite had the most excellent adsorption performance and good stability, and reusability. The adsorption removal rate of Cr(VI) can reach 99%, and the maximum adsorption amount of Cr(VI) was 68.9655 mg/g in 3 h. The isothermal and kinetic model simulations showed that Cr(VI) adsorption on ZnrGO 0.1 composite is a chemical adsorption process, spontaneous and endothermic. Based on the concentrations of different valence states of Cr in the solid and liquid phases, 40% of Cr(VI) was reduced to Cr(III) on the surface of ZnrGO 0.1 composite. Moreover, the adsorption-reduction mechanisms of Cr(VI) on ZnrGO 0.1 composite were further elucidated. The ZnrGO 0.1 composite manifested great potential as an efficient adsorbent for Cr(VI) removal. Graphical Abstract
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2024
·
IF 9.4
Zhenyang Song,Yuting Xu,Mengyuan Zhang,Wei Zhu,Xudong Yang,Di Hao,Qing Li
Hypothesis Hexavalent chromium, recognized as one of the most toxic heavy metals, demands the development of advanced materials capable of both adsorption and photocatalysis for effective Cr (VI) removal. Experiments This study successfully synthesized a two-dimensional zinc porphyrin covalent organic framework (ZnPor-COF) via a solvent-based method. Performance evaluations have demonstrated that the ZnPor-COF possesses outstanding capabilities for the adsorptive and/or photocatalytic elimination of Cr (VI). Particularly noteworthy is the observation that when adsorption and photocatalysis are coupled, the ZnPor-COF attains an exceptional 99.7 % removal rate for a Cr (VI) concentration of 30 mg/L within just 60 min, with minimal susceptibility to coexisting ions. After five consecutive cycles, the material sustains a removal efficiency of 90 %, indicative of its robust cyclability. Findings Theoretical calculations, as well as experimental validations, have indicated that the integration of Zn ions into the porphyrin COF not only results in an expanded specific surface area and an increased count of adsorption sites but also significantly improves the COF’s photosensitivity and the capability for charge carrier separation. Furthermore, the core of the synergistic effect between adsorption and photocatalysis lies in the ability of photocatalysis to substantially augment the adsorption process.
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JOURNAL OF ENVIRONMENTAL MANAGEMENT
·
2024
·
IF 8
Yuhang Yang,Bing Li,Mingxi Li,Zhiyi Deng,Zuoyi Chen,Jinhua Wu
Zero-valent iron (Fe 0 ) usually suffers from organic acid complexation and ferrochrome layer passivation in Cr(VI) removal from bioleached wastewater of Cr slag. In this work, a synergetic system combined Fe 0 and mixed hetero/autotrophic bacteria was established to reduce and stabilize Cr(VI) from bioleached wastewater. Due to bacterial consumption of organic acid and hydrogen, severe iron corrosion and structured-Fe(II) mineral generation (e.g., magnetite and green rust) occurred on biotic Fe 0 surface in terms of solid-phase characterization, which was crucial for Cr(VI) adsorption and reduction. Therefore, compared with the abiotic Fe 0 system, this integrated system exhibited a 6.1-fold increase in Cr(VI) removal, with heterotrophic reduction contributing 3.4-fold and abiotic part promoted by hydrogen-autotrophic bacteria enhancing 2.7-fold. After reaction, the Cr valence distribution and X-ray photoelectron spectroscopy indicated that most Cr(VI) was converted into immobilized products such as Fe x Cr 1-x (OH) 3 , Cr 2 O 3 , and FeCr 2 O 4 by biotic Fe 0 . Reoxidation experiment revealed that these products exhibited superior stability to the immobilized products generated by Fe 0 or bacteria. Additionally, organic acid concentration and Fe 0 dosage showed significantly positive correlation with Cr(VI) removal within the range of biological adaptation, which emphasized that heterotrophic and autotrophic bacteria acted essential roles in Cr(VI) removal. This work highlighted the enhanced effect of heterotrophic and autotrophic activities on Cr(VI) reduction and stabilization by Fe 0 and offered a promising approach for bioleached wastewater treatment .
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SCIENCE OF THE TOTAL ENVIRONMENT
·
2024
·
IF 8.2
Liuyuan Tang,Jing Yang,Xiaona Liu,Lingke Kang,Wenjun Li,Ting Wang,Tianwei Qian,Bo Li
Microorganisms capable of simultaneously remediating heavy metals (HMs) and polycyclic aromatic hydrocarbons (PAHs) pollution hold significant importance in bioremediation efforts. In this study, we investigated the ability of Pseudomonas aeruginosa AO-4 to simultaneously degrade phenanthrene (PHE) and reduce Cr (VI). Specifically, it has the ability to reduce 100 % of Cr (VI) (30 mg/L) while degrading 43.8 % of PHE (50 mg/L). In batch experiments, it was observed that the presence of Cr (VI) can enhance the degradation of PHE by strain AO-4. The solubility of PHE in soluble extracellular polymeric substances (S-EPS) was found to be related to the initial concentration of Cr (VI), which could explain why Cr (VI) promotes the degradation of PHE. Additionally, XPS analysis confirmed that Cr (VI) was reduced to Cr (III) with S-EPS produced by Pseudomonas aeruginosa AO-4. GC–MS analysis was conducted to analyze the degradation metabolites of phenanthrene, di(2-ethylhexyl) phthalate and 2TMS derivatives of salicylic acid were detected, indicating that Pseudomonas aeruginosa AO-4 is capable of degrading phenanthrene through two distinct pathways. These findings demonstrate the potential of Pseudomonas aeruginosa AO-4 in the treatment of co-contamination scenarios involving PAHs and HMs.
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APPLIED CATALYSIS B-ENVIRONMENTAL
·
2024
·
IF 20.2
Hui Li,Li Du,Ying Zhang,Xu Liu,Shuang Li,Chun Cheng Yang,Qing Jiang
The rational construction of high-efficiency transition metal phosphides catalysts for hydrogen evolution reaction (HER) is crucial since their sluggish kinetics of water dissociation remain severe barriers for HER performance. The theoretical calculations indicate a unique adsorption-diffusion-decomposition mechanism for H 2 O molecules on CoP (111) surface. Herein, Fe could decrease H 2 O decomposition barrier energies and increase the amount of active sites, along with Cr could accelerate H 2 O adsorption, diffusion and increase the conductivity of the reaction surface. Aided by this mechanism, a self-supported electrode of Cr and Fe dual-doped CoP nanorod arrays grown on nickel foam was prepared. The electrode only requires an overpotential of 27 mV at 10 mA cm −2 for alkaline HER with excellent durability for 400 h. Moreover, the catalyst presents only 1.505 V at 10 mA cm −2 for alkaline water electrolysis. This work provides an in-depth understanding on catalytic mechanism of CoP-based materials.
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MICROCHEMICAL JOURNAL
·
2024
·
IF 4.9
Li Gong,Siwei Jin,Renlong Liu,Zuohua Liu,Yijiao Zhang,Li Zhang,Tengda Zhao,Huanbao Fa,Wei Yin
Achieving the real-time, low-cost, portable and accurate NH 3 detection is of great importance in industry owing to the toxicity of NH 3 . In this paper, Pt NPs@MIL-101-NH 2 composites modified screen-printed electrodes (SPEs) were prepared by solvothermal method and ionic liquids [BMIM][BF 4 ] were used as electrolytes. Finally, the prepared Pt NPs@MIL-101-NH 2 /SPEs were combined with a miniature electrochemical workstation to construct a novel electrochemical NH 3 sensor. The experimental results showed that Pt NPs@MIL-101-NH 2 has excellent adsorption capacity for NH 3 , and the sensor has good linearity in the range of 0.7–600 ppm with low limit of detection (0.58 ppm) and fast response time for 10 ppm NH 3 (8.0 s). Furthermore, this sensor also possesses excellent stability, reproducibility, anti-interference and accuracy. The synthesized Pt NPs@MIL-101-NH 2 nanocomposite was proved to be an excellent candidate for constructing high-performance NH 3 sensor for industry.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Yixin Pan,Leilei Sun,Zhixin Yu,Xiahui Guo,Lujia Chen,Man Huang
In this study, a composite material (FeS-Mor) of nano ferrous sulfide (FeS) and mordenite was prepared by coprecipitation method using mordenite as a stabilizer to prevent the aggregation of FeS to achieve the purpose of efficient removal of chromium from water. Experimental results revealed that the optimum pH for Cr(VI) removal was ∼ 2 with a removal capacity of 199.0 mg/g and efficiency of 99.5 % at 303 K. Common co-existing cations of Na + , Ca 2+ and K + promoted the removal efficiency, while Mg 2+ inhibited the removal of Cr(VI). While Common anions of SO 4 2− , CO 3 2− , Cl − and NO 3 − inhibited chromium removal. The pseudo-second-order kinetics model fitted the kinetic removal of Cr(VI) onto FeS-Mor composites best under absent/present co-existing cations, indicating that chemical reduction and complexation dominated the removal process. The thermodynamic results were best described with the Freundlich model and showed an endothermic process of Cr(VI) removal. The FeS-Mor composites with FeS:Mor mass ratio in the range of 1:1–1:2 exhibited the best performance in removal efficiency and reusability. These results reveal that introducing mordenite to develop an efficient FeS-based nanocomposite system can significantly improve the performance of chromium remediation from aqueous solutions.
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ENVIRONMENTAL POLLUTION
·
2024
·
IF 7.6
Yijin Yuan,Qi Tian,Longzhu Hou,Richuan Rao,Chengli Yao,Haoyan Zhu
The treatment of textile wastewater containing harmful metal ions poses a significant challenge in industrial applications due to its environmental impact. In this study, the use of sulfite for treating simulated dye wastewater containing New Coccine (NC) and Cr(VI) was investigated. The removal of NC was influenced by the redox reaction between Cr(VI) and sulfite, demonstrating a strong self-boosting effect of Cr(VI) on NC removal. Remarkable NC decoloration (95%) and Cr(VI) reduction (90%) were achieved within 1 min, highlighting the effectiveness of the treatment. Quenching experiments and electron paramagnetic resonance (EPR) technology confirmed that singlet oxygen ( 1 O 2 ) was the main oxidative agent for organic dye removal and SO 4 •− , •OH and Cr(V) were also identified as key contributors to NC degradation. The Cr(VI)/sulfite system exhibited higher efficiency in degrading azo dyes, such as NC and Congo Red (CR), compared to non-azo dyes like Methylene Blue (MB). This superiority may be attributed to the action of Cr(V) on azo groups. Additionally, the COD removal experiments were conducted on the actual dye wastewater, showing the excellent performance of the Cr(VI)/Sulfite system in treating industrial textile wastewater. This approach presents a promising strategy for effective “waste control by waste”, offering great potential for addressing challenges related to dye wastewater treatment and environmental pollution control in practical industrial scenarios.
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ENVIRONMENTAL RESEARCH
·
2024
·
IF 7.7
Jiwen Li,Yaqian Duan,Linlin Wang,Jingjun Ma
The poor light absorption and low carrier separation efficiency of Titanium dioxide (TiO 2 ) limit its further application. The introduction of plasma metal Ag have the potential to solve these drawbacks owing to its plasma resonance effect. Thus core-shell structure Ag@TiO 2 plasma photocatalysts was prepared by using facile reduction method in this work. More specifically, Ag@TiO 2 composite catalysts with different Ag loading amounts were prepared in the presence of surfactant PVP. Ag@TiO 2 demonstrates excellent light absorption performance and photoelectric separation efficiency compared with pure TiO 2 . As a result, it displays excellent performance of Cr(VI) reduction under visible light. The optimal composite catalysts Ag@TiO 2 –5P achieves exceptional visible-light-driven photocatalytic Cr(VI) reduction efficiency of 0.01416 min −1 that is 2.29 times greater than pure TiO 2 . To investigate the role of PVP, we also synthesized Ag@TiO 2 -5 without PVP. The experimental results show that although Ag@TiO 2 -5 Cr(VI) reduction performance is superior to pure TiO 2 , it significantly decreases compared with Ag@TiO 2 –5P. The results of TEM and optoelectronic testing show that agglomeration of Ag particles leads to a decrease in the photoelectric separation efficiency of Ag@TiO 2 -5. The smaller Ag particles provide more active sites and demonstrating a stronger overall local surface plasmon resonance (LSPR) effect. DMPO spin-trapping ESR spectra testing indicates that ∙O 2 − and ∙OH are the main reactive species. This research provides a potential strategy to prepare Ag-based plasma photocatalysts for environment protection.
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2024
·
IF 8.1
Xitao Qiao,Shuaidong Wang,Xin Han,Jiaye Qin,Yanyan Wang,Guangke Tian
Cu 2 S and Cu–S based materials with the introduction of 15 at% and 63% at% Cr respectively were prepared on carbon cloth (CC) (Cu 2 S/CC, Cu 5.6 CrS 6 /CC and CuCr 1.4 S 5 /CC) by one-pot hydrothermal synthesis. It was found that the phase composition and morphology of Cu–S undergo significant changes with the introduction of Cr content, thereby impacting their electrocatalytic hydrogen evolution reaction (HER) properties. In particular, for Cu 5.6 CrS 6 /CC, 15 at% Cr introduction facilitated the formation of a highly catalytically active Cu 7 S 4 -dominant phase and a hexagonal flake-like morphology with a large specific surface area conducive to fully exposing the catalytically active sites. The synergistic advantages in morphology and phase composition endow Cu 5.6 CrS 6 /CC with the best HER electrocatalytic performance with a low overpotential of 81 mV (10 mA cm −2 ) and 142 mV (100 mA cm −2 ), a Tafel slope of 43 mV dec −1 , and 10000 cycle stability. This study provides an idea for implementing a synergistic strategy of phase engineering and morphology modulation by introducing Cr to construct high-performance HER catalysts.
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