Environmental Science-Nano
·
2017
·Vol. 5
·期 2
·487-496
·
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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TALANTA
·
2017
·
IF 4.162
Li Liang,Xinghua Wang,Ying Sun,Pinyi Ma,Xinpei Li,Huilan Piao,Yanxiao Jiang,Daqian Song
The metal-organic framework (MOF) functionalized magnetic graphene oxide/mesoporous silica composites (Fe 3 O 4 @SiO 2 -GO/MIL-101(Cr)) were synthesized and utilized as magnetic solid-phase extraction (MSPE) adsorbent for the extraction of seven triazine herbicides (terbuthylazine, secbumeton , terbumeton , atraton , atrazine , prometon and trietazine) in rice samples. Several experimental parameters, including type and volume of extraction solvent, amount of MIL-101(Cr), extraction time, volume of desorption solvent and desorption time were investigated and optimized. The limits of detection (LODs) of seven triazine herbicides obtained by using the proposed MSPE method combined with high performance liquid chromatography (HPLC) were in the range of 0.010–0.080 µg kg −1 . The recoveries of the triazine herbicides in spiked rice samples ranged from of 83.9–103.5% with the relative standard deviations lower than 8.7%. The intra and inter-day (n = 6) precisions for all triazine herbicides at the spiked level of 100.0 µg kg −1 were 1.4–5.9% and 2.6–7.8%, respectively.
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高影响因子
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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SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Fenglei Liu,Linkai Si,Baowei Hu
Herein, we proposed a novel chitosan-induced self-assembly strategy to construct three-dimensional magnetic MXenes/chitosan composites to eliminate U(VI)/Cr(VI). Spectroscopic analysis elucidated that the magnetic composites exhibited a three-dimensional network structure, and the abundant –OH and –NH 2 groups played a pivotal role in boosting elimination performance of the composites. Batch experiment demonstrated that the synergistic effect of the amino and hydroxyl groups contributed greatly to adsorption, and the maximum adsorption capacity of U(VI) and Cr(VI) was up to 106.2 and 83.1 mg/g, respectively. Meanwhile, the kinetic studies showed that an obvious transition between diffusion control and mass transfer control, and the adsorption behavior was endothermic and spontaneous. Furthermore, a comprehensive synergistic adsorption mechanism was proposed based on the systematic spectra analysis. Namely, the target contaminant was rapidly immobilized on the 3D composites via electrostatic interaction, then the U(VI) was complexed with the amino groups, while a part of Cr(VI) was reduced to Cr(III) by the hydroxyl groups. Thus, this study not only paved the way for mitigating the increasing heavy metal/radionuclide contamination, but also promoted the application of MXexes-based materials in the field of environmental remediation.
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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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PubMed
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2024
·
IF 4.9
Jingfang Guo,Guodong Wang,Jing Zou,Zhen Lei
In this work, chitosan modified cuprous oxide nanoparticles (Cu 2 O/CTS NPs) with Cr(VI)-specific oxidoreductase-like activity were facilely synthesized via one-step reduction method. In the presence of Cr(VI), colorless 3,3′,5,5′-tetramethylbenzidine (TMB) was rapidly oxidized to blue colored oxTMB with the aid of Cu 2 O/CTS NPs. Systematic studies including steady-state kinetics analysis, X-ray photoelectron spectra (XPS) analysis, radical trapping experiments and photoluminescence spectroscopy were conducted to investigate the catalytic mechanism, which was verified to be electron transfer and active species-involved redox reaction. Based on promoted catalytic oxidation of TMB, a selective and sensitive colorimetric method for fast detection of Cr(VI) was proposed. Under the optimal conditions, this colorimetric method exhibited a wide linear range (0.01–35 μM), low limit of detection (0.5 nM) and short assay time (1 min). In addition, test strip for visual detection of Cr(VI) was constructed by processing the Cu 2 O/CTS NPs+TMB+Cr(VI) sensing system on paper. With the aid of smartphone, a detection limit of 312 nM was achieved within 5 min, showing great potential for on-site detection. Moreover, the method was applied to detect Cr(VI) in spiked tap and lake water samples, the good recoveries (96.10%−103.13%) and low relative standard deviations (1.03%−3.25%) demonstrated the feasibility of the assay.
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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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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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Frontiers in Microbiology
·
2016
·
IF 4.165
Han Rui,Li Fangbai,Liu Tongxu,Li Xiaomin,Wu Yundang,Wang Ying,Chen Dandan
It is widely recognized that the outer membrane c-type cytochromes (OM c-Cyts) of metal-reducing bacteria play a key role in microbial metal reduction processes. However, the in situ redox status of OM c-Cyts during microbial metal reduction processes remain poorly understood. In this study, diffuse-transmission UV/Vis spectroscopy is used to investigate the in situ spectral reaction of Cr(VI) reduction by c-Cyts in intact Shewanella oneidensis MR-1 cells under different incubation conditions. The reduced c-Cyts decreased transiently at the beginning and then recovered gradually over time. The Cr(VI) reduction rates decreased with increasing initial Cr(VI) concentrations, and Cr(III) was identified as a reduced product. The presence of Cr(III) substantially inhibited Cr(VI) reduction and the recovery of reduced c-Cyts, indicating that Cr(III) might inhibit cell growth. Cr(VI) reduction rates increased with increasing cell density. The highest Cr(VI) reduction rate and fastest recovery of c-Cyts were obtained at pH 7.0 and 30∘C, with sodium lactate serving as an electron donor. The presence of O2 strongly inhibited Cr(VI) reduction, suggesting that O2 might compete with Cr(VI) as an electron acceptor in cells. This study provides a case of directly examining in vivo reaction properties of an outer-membrane enzyme during microbial metal reduction processes under non-invasive physiological conditions.
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高影响因子
RSC Advances
·
2016
·Vol. 6
·期 98
·95469-95475
·
IF 3.289
Lingli Bu,Jingdong Peng,Huanjun Peng,Shaopu Liu,Huan Xiao,Dan Liu,Ziyu Pan,Yu Chen,Fang Chen,Yan He
Chromium(VI) is proved to be highly carcinogenic and mutagenic, thus sensitive and rapid sensors for monitoring Cr(VI) are in urgent demand. In this work, a facile fluorescent assay for the sensitive and selective detection of Cr(VI) was proposed based on static quenching combined with inner filter effect (IFE) using phosphate functionalized carbon dots (PCDs) as nanoprobes. A good linear quenching was observed in the range of 1.0–400 μM with a detection limit of 0.24 μM (σ/S = 3) under the optimized conditions. The nanoprobe was employed for detecting Cr(VI) in real water samples including river water and tap water with satisfactory recovery. Moreover, with the addition of Cr(VI), the color changes of PCDs can be easily observed by the naked eye under a UV lamp. Based on this, Cr(VI) test papers were fabricated for spot quick detection of Cr(VI).
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APPLIED SURFACE SCIENCE
·
2016
·
IF 3.15
Yuanfeng Pan,Pingxiong Cai,Madjid Farmahini-Farahani,Yiduo Li,Xiaobang Hou,Huining Xiao
Pentaerythritol (PER) was esterified with 2-bromoisobutyryl bromide to synthesize a four-arm initiator 4Br-PER for atom transfer radical polymerization (ATRP). Star-shaped copolymers (P(AM- co -DMAEMA) 4 , CSP) were prepared via ATRP using dimethyl aminoethyl methacrylate (DMAEMA) and acrylamide (AM) as comonomers, while Br-PER and CuBr/2,2′-bipyridine (BPY) as the initiator and the catalyst, respectively. The resulting four-arm initiator and star-shaped polymer (CSP) were characterized with FT-IR, 1 H NMR and Ubbelohde viscometry. Alkaline clay (AC) was immobilized with CSPs to yield amino groups, and the cationic star polymer-immobilized alkaline clay (CSP-AC) was applied to remove Cr(VI) from the aqueous solution in batch experiments. Various influencing factors, including pH, contact time and immobilization amount of CSP on adsorption capacity of CSP-AC for Cr(VI) were also investigated. The results demonstrated that Cr(VI) adsorption was highly pH dependent. The optimized pH value was 4.0. The adsorption isotherms of the adsorbent fit the Langmuir model well, with the maximum adsorption capacity of 137.9 mg/g at 30 °C. The material should be a promising adsorbent for Cr(VI) removal, with the advantages of high adsorption capacity.
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RSC Advances
·
2016
·Vol. 6
·期 32
·27039-27046
·
IF 3.289
Honglin Yao,Qianqian Ding,Hongjian Zhou,Zhenfu Zhao,Gang Liu,Guozhong Wang
In this study, mesoporous amino-group functionalised iron/silica hollow spheres (Fe/SiO2–NH2 HSs) were successfully developed as a magnetic absorbent for the highly effective removal of Cr(VI) ions. The Fe/SiO2–NH2 HSs were synthesized using monodispersed silica colloids as a chemical template, followed by a one-pot hydrothermal treatment, hydrogen reduction and surface modification with an amino silane coupling agent. The Fe/SiO2–NH2 HSs have a diameter of ca. 950 nm and a shell thickness of ca. 60 nm, and the surfaces were composed of Fe and SiO2 units with amino functional groups. Meanwhile, the ferromagnetic property endowed them with easy recyclability for practical applications. The Fe/SiO2–NH2 HSs exhibited significantly improved ability to remove pollutant Cr(VI) and methyl orange. The removal percentage of Cr(VI) (8 mg L−1) could reach 98.3% in just 5 min using Fe/SiO2–NH2 HSs; however, only 10% of Cr(VI) were removed using the unmodified samples. XPS analysis suggested that the removal of Cr(VI) was attributed to the adsorption and reduction synergistic process of the Fe/SiO2–NH2 HSs. During the process, an electrostatic attraction occurred between the positively charged amino-groups and the negatively charged pollutant species in the aqueous solution, and adsorbed Cr(VI) ions were reduced to Cr(III) species by the iron of Fe/SiO2–NH2 HSs.
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