INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2023
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IF 8.2
Chunzi Xu,Yunlan Xu,Dengjie Zhong,Haixing Chang,Jiaxin Mou,Hui Wang,Hongyu Shen
In order to improve the stability, electrostatic interaction and ion exchange ability of chitosan for Cr (VI) removal, it is an effective strategy to introduce polyvalent metal ions and polymers into chitosan molecular chain through crosslinking. In this paper, Zr 4+ and glutaraldehyde crosslinked polyethyleneimine functionalized chitosan (CGPZ) composite was successfully synthesized and characterized by XRD, SEM, FTIR , BET, and XPS . The results showed that polyethyleneimine was successfully grafted onto chitosan by Schiff base reaction, while the appearance of Zr O and Zr N bonds verified the successful preparation of CGPZ. The monolayer maximum adsorption capacity of Cr(VI) by CGPZ was 593.72 mg g −1 at 298 K and t = 210 min. The removal efficiency of 100 mg L −1 Cr(VI) reached 95.7 %. The thermodynamic, isotherm and kinetic results show that the adsorption process of Cr (VI) by CGPZ is a spontaneous endothermic process controlled by entropy, which accords with Freundlich model and pseudo-second-order kinetic model. The regeneration experiments show that both HCl and NaOH can effectively desorb Cr(III) and Cr(VI) from the adsorbent surface, and the adsorbent has good acid-base resistance and regeneration performance. The removal of Cr(VI) mainly involves electrostatic attraction, ion exchange, reduction and complexation. CGPZ can synergistically adsorb Cr(VI) by electrostatic interaction of -NH 2 /-C=N and ion exchange of Cl − ion in the center of Zr, then reduce Cr(VI) to Cr(III) (45.4 % at pH = 2.0) by the -OH group on its surface, and chelate Cr(III) through COO- and -NH- groups.
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Analytical Methods
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2022
·Vol. 15
·期 2
·221-227
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IF 3.532
Xianyuan Xu,Jingfang Guo,Zhen Lei
A recyclable peroxidase mimic Fe3O4@polydopamine/Prussian blue (Fe3O4@PDA/PB) composite was facilely prepared by coating PDA on an Fe3O4 nanoparticle core and in situ growth of PB nanoparticles on a PDA shell. The prepared Fe3O4@PDA/PB composite exhibited excellent peroxidase-like activity and can catalytically oxidize the colorless colorimetric substrate 3,3′,5,5′-tetramethylbenzidine (TMB) into a blue colored product in the presence of H2O2 at 30 °C in 1 min. The catalytic mechanism was deduced to be the nanozyme-promoted generation of a hydroxyl radical (·OH), and the catalytic behavior followed the typical Michaelis–Menten kinetics. Based on Cr(VI)-boosted peroxidase-like activity of Fe3O4@PDA/PB, a simple and fast colorimetric method for detection of Cr(VI) was developed. Under the optimum conditions, the colorimetric method exhibited wider linear range (100 nM to 140 μM), low LOD (51.1 nM), good selectivity and short detection time (1 min). Moreover, the feasibility of the proposed colorimetric method was evaluated by determination of Cr(VI) in spiked tap water and lake water samples. Good recoveries (95.2–102.9%) and low relative standard deviations (RSDs) (1.6–4.4%) were obtained, showing great promise for practical use.
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Arabian Journal of Chemistry
·
2023
·
IF 6
Qingrong Han,Fei Liu,Chengjiu Wang,Zhentao Tang,Cheng Peng,Yuzhu Tan
In recent years, the quality and safety issues of Chinese medicinal herbs have received great attention worldwide. Thereinto, heavy metal contamination has been one of the most serious concerns. Compared to the wide research in the analysis of heavy metals in medicinal herbs, the studies on the removal of heavy metals are relatively limited. In this study, polyethylene glycol functionalized Fe 3 O 4 @MIL-101(Cr) (Fe 3 O 4 @MIL-101(Cr)@PEG) was designed and synthesized to remove heavy metals from the decoction of Ligusticum chuanxiong Hort. The in-house fabricated Fe 3 O 4 @MIL-101(Cr)@PEG was characterized by a porous structure and a large specific surface area. Then, the efficiency of the material for the removal of five heavy metals was tested under optimal adsorption conditions. Meanwhile, the content of Senkyunolide A, Senkyunolide I, and Ferulic acid, the solid content, and the HPLC fingerprints similarity were used as the quality monitoring indicators of Ligusticum chuanxiong Hort decoction before and after the heavy metal removal. Results showed that the magnetic nanomaterial had excellent removal efficiency for As 5+ (81.4 %), Cd 2+ (88.19 %), and Pb 2+ (83.79 %) and certain removal efficiency for Ni 2+ (51.59 %) and Zn 2+ (55.4 %) under the spiked concentration of 50 μg/mL. The content of Senkyunolide A, Senkyunolide I, and Ferulic acid were decreased by less than 8.00 % after the removal of heavy metals. Besides, the loss rate of solid content was only 0.18 %, and the fingerprints similarity was over 99.9 %. The results indicated that Fe 3 O 4 @MIL-101(Cr)@PEG could efficiently and selectively remove heavy metals from Ligusticum chuanxiong Hort without affecting its effective components. Due to the advantages of low-cost, simple manipulation, and good efficiency, the material can be recommended for heavy metals removal from the aqueous solutions of medicinal herbs, providing a new and promising application for the removal of exogenous contaminants in medicinal herbs.
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INDUSTRIAL CROPS AND PRODUCTS
·
2023
·
IF 5.9
Xiaojing Qin,Rongrong Tao,Song Cheng,Baolin Xing,Weibo Meng,Yanhe Nie,Chuanxiang Zhang,Jianglong Yu
ZnO based-double functional biochar (ZnO-BC) derived pine sawdust is prepared by microwave heating using simple one-pot method for levofloxacin (LEV) and Cr(Ⅵ) removal from wastewater. ZnO-BC has well developed pore structure with BET surface area of 915.47 m 2 /g, which also has well ZnO crystalline. These characteristics make ZnO-BC available as the adsorbent and photocatalyst for LEV and Cr(Ⅵ) removal wastewater. LEV and Cr(Ⅵ) adsorption date fit well with the Hill and Pseudo-second order equation with LEV and Cr(Ⅵ) adsorption amount of 193.42 and 21.03 mg/g, respectively. The LEV and Cr(Ⅵ) adsorption behavior are determined by the chemisorption process. The hydrogen bond, π-π interaction, surface complexation, pore filling are responsible for LEV removal. While the hydrogen bonding, complexation and redox are crucial to the removal of Cr(Ⅵ) from wastewater. LEV removal is 85.72–97.19% at 15–25 mg/L at 120 min, and Cr(Ⅵ) removal is 72.62–99.9% at 40–60 mg/L at 75 min under UV irradiation. The possible photocatalytic mechanisms of the LEV and Cr(Ⅵ) are further investigated and analyzed.
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CHEMOSPHERE
·
2023
·
IF 8.8
Yang-xiao-xiao Shi,Jia-qi Cui,Feng Zhang,Ke-wei Li,Jun Jiang,Ren-kou Xu
Hexavalent chromium (Cr(VI)) is a toxic heavy metal and its mobility and bioaccessibility in soils are influenced by soil properties. In this study, the soil pH and organic carbon contents of Ultisol , Alfisol , and Inceptisol were adjusted before they were polluted with 230 mg kg −1 Cr(VI). Alkaline digestion, sequential extraction, and an in vitro experiment were conducted to study the valence state, species, and bioaccessibility of Cr in the soils. The results showed that a high soil pH was not favorable for reduction of Cr(VI); therefore the Cr(VI) and exchangeable Cr contents were positively related to soil pH. Soil organic carbon promoted the reduction of Cr(VI). Almost all Cr(VI) was reduced to Cr(III) when the soil organic carbon content reached 10 g kg −1 . Chromium bioaccessibility in simulated gastric and intestinal phase solutions was influenced by Cr(VI) and Cr(III) adsorption/desorption, dissolution/precipitation, and redox reactions. Chromium bioaccessibility differences between the gastric and intestinal phases were associated with the Cr(VI)/Cr(III) ratio. Acidic conditions and a high organic carbon content promoted the conversion of Cr(VI) to Cr(III). When soil pH was increased from 4.01 to 5.85, Cr(VI) in Alfisol without the addition of humic acid increased from 96.38 to 174.78 mg kg −1 , the exchangeable Cr proportion increased from 9.7% to 22.6%, and Cr bioaccessibility increased from 41.29% to 49.14% in the gastric phase and from 41.32% to 48.24% in the intestinal phase. When the organic carbon content increased from 3.95 to 9.28 g kg −1 in Alfisol, Cr(VI) content decreased from 167.66 to 20.52 mg kg −1 , which led to a decrease in Cr bioaccessibility from 49.15% to 13.8% in the gastric phase and from 45.85% to 7.67% in the intestinal phase. Therefore, acidic conditions and increasing soil organic carbon levels can reduce the health risk posed by Cr in soils.
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International Journal of Electrochemical Science
·
2023
·
IF 1.5
Yuhan Yao,Zhaolin Zhan,Jianxiong Liu,Xiao Wang,Xiaohua Yu,Ju Rong
Response surface methodology (RSM) was used in this study to determine the optimum operating conditions for the reduction of galvanized sheet corrosion using a Cr-free passivation films. Passivation films layer with strong corrosion resistance was formed on the surface of galvanizing which was impregnated in chromium-free passivating agent. Furthermore, the RSM was used to ascertain the main and interactive effects (deviation between the experimental and theoretical values: 0.12%). The coefficient of determination (R 2 ) showed that the RSM approach was appropriate for optimization of the Cr-free passivator. Silane coupling agent, ammonium molybdate, nanosilica, and tannic acid played a key role in changing the corrosion area and potential. The results revealed that, compared with Cr 6+ passivation, Cr-free passivation yielded considerably more homogeneous and smoother surfaces (surface roughness of Cr-free passivation film: 0.54 μm). In addition, the properties of the zinc coating after Cr- free passivation were clearly superior to those of the zinc coating subjected to the conventional Cr 6+ passivation treatment. E corr, current density, and polarization resistance values of this superior coating were -1073 mV, 0.017 A cm -2 , and 989.2 Q, respectively. This study can serve as an experimental and a theoretical guide for the development of Cr-free passivation films.
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JOURNAL OF ALLOYS AND COMPOUNDS
·
2023
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IF 6.2
Yangjie Fu,Yanjie Mao,Longyang Wang,Mengyi Qiu,Youran Xu,Jianying Qian,Men Tan,Kejie Zhang,Derek Hao,Qi Wang,Guoxiang Yang
Proper design and successful synthesis of photocatalysts with efficient interfacial charge transfer, strong redox capabilities, and strong environmental applications are critical. Herein, a novel Z-scheme heterojunction AgI/Ce-2MI nanocomposite with redox-retaining properties was successfully prepared by a simple precipitation method. Compared with AgI and Ce-2MI, the efficiency of the optimized Z-scheme AgI/Ce-2MI composites in photocatalytic reduction of Cr(VI) in water within 75 min could exceed 90%. The reduction rate of AgI/Ce-2MI to Cr(VI) was 0.0277 min −1 , which was 2.6 times and 6.8 times that of AgI and Ce-2MI, respectively. In addition, the cycle performance of AgI/Ce-2MI under different pH conditions was compared, and it was found that under the condition of pH= 2, its five-time catalytic activity stability showed good performance. Moreover, the enhancement process of reactive oxygen species •O 2 - and •OH were further verified by active radical capture experiment and ESR. Therefore, this study can provide a Z-scheme heterojunction nanocomposite photocatalytic process with environmental purification functions.
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JOURNAL OF DISPERSION SCIENCE AND TECHNOLOGY
·
2023
·
IF 2.2
Hui Wang,Dengjie Zhong,Yunlan Xu,Haixing Chang,Hongyu Shen,Chunzi Xu,Jiaxin Mou,Nianbing Zhong,Bin Tang
In this work, in view of the poor adsorption capacity of sludge-based biochar, a sludge-based biochar adsorbent co-modified with hydrochloric acid and polypyrrole (PPy/SBC-HCl) was prepared and used to remove Cr(VI) from aqueous solution. Its characterization of SEM, EDS, BET, XRD, FT-IR, and XPS show that the removal mechanism of Cr(VI) by PPy/SBC-HCl includes electrostatic adsorption, ion exchange, reduction, and complexation. The removal efficiency of Cr(VI) by PPy/SBC-HCl decreases with the increase of pH. The coexisting cations Ca2+ and Mg2+ have a slight negative effect on it, while the oxoacid anions have a great negative effect on it. The adsorption of Cr(VI) by PPy/SBC-HCl is a spontaneous endothermic process, which conforms to the pseudo-second-order adsorption kinetic model and the Freundlich adsorption isotherm model. The maximum adsorption capacity is 97.37 mg g−1 at pH 2.0 and temperature 298 K.
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ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY
·
2022
·
IF 7.129
Shengliang Zhao,Xuandi Lai,Feiyan Liu,Liqiong Chen
Hexavalent chromium (Cr(VI)) determination is of great importance to the public health because of its extensive sources and high toxicity. However, interference from non-target ions and complex matrix remains challenges for Cr(VI) detection. In this work, we constructed a novel sensing system for high selectivity detection of Cr(VI), which is composed of strong emitting carbon dots (CE-CDs) and a specific masking agent. The detection conditions, anti-interference capability and the sensing and masking mechanisms of CE-CDs-based sensing method were systematically investigated. The results revealed that the optimal detection conditions included pH 4–10, reaction time 180 s and CE-CDs concentration 18 mg/L. Under optimal conditions, the linear range of the method was up to 500 µm, and the detection limit was as low as 23 nM. In addition, the interference of Hg(II) can be accurately eliminated by using DMPS, an effective masking agent. During the sensing process, inner filter effect and ion-molecular interaction between Cr(VI) and CE-CDs accounted for the fluorescence quenching mechanism, while the efficient masking was attributed to the strong coordination interaction between Hg(II) and DMPS. Most notably, this method had broad applicability, even for the trace detection of Cr(VI) in colored leather with complex matrix. These findings indicate that this approach is expected to open up new avenues for Cr(VI) detection.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2022
·
IF 9.136
Ruimeng Wang,Xinqi Luan,Jingyu Bao,Yaseen Muhammad,Syed Jalil Shah,Guanchen Wang,Jing Li,Guoyou Lin,Hongbing Ji,Zhenxia Zhao
High capacity adsorption of volatile organic compounds (VOCs) in high humidity environment is a crux but challenge for atmospheric VOCs governance. In this work, tubular carbonized N-doped polymers (TCNP) were implanted into MIL-101 via N-Cr-O interface self-assembly, enabling high adsorption for vapor toluene in high humidity. Through mechanical ball milling and carbonization, Cr ions were preloaded on TCNP to form highly dispersed 3–5 nm Cr-N crystallite as anchors for growing MIL-101(Cr/Cu). Newly constructed smaller micropores of 6.8 Å with aromatic rings/N sites at the interface and doped Cu ions in MOF framework synergistically enhanced π-π conjugation and electrostatic interaction for C 7 H 8 molecules. This endowed [TCNP 5 /MIL(Cr/Cu)] N-Cr 2.9 times higher toluene uptake (6.34 mmol/g) at low vapor pressure ( P / P 0 = 0.02) and 1.9 times diffusivity under high humidity (60% RH) than that of MIL-101(Cr) at 298 K. The adsorption breakthrough curves for vaporous toluene showed that TCNP@MIL-101(Cr/Cu) exhibited outstandingly higher adsorption equilibrium capacity (2.7 mmol/g) under 80% RH, corresponding to approximately 2–10 times than those of reported state-of-the-art adsorbents under similar conditions. This study provided a novel interface construction strategy for hydrophobic MOF composites, which supplied deeper understanding for VOCs adsorption and promoted MOFs practical application in VOCs capture under humid environment.
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JOURNAL OF SOLID STATE CHEMISTRY
·
2022
·
IF 3.656
Meng Chen,Chao Wang,Lei Wang,Jixiang Xu
In this work, carbon quantum dots@In 2 S 3 hollow tube (CQDs@In 2 S 3 ) with sheet-like hierarchical structure was synthesized by sulfidation CQDs@In-MIL-68. The CQDs@In 2 S 3 -2 exhibited the optimal Cr(VI) reductive ratio of nearly 100% after 45 min light irradiation in solution with pH of 4. The enhanced Cr(VI) reduction activity was ascribed to the efficient separation of electrons and holes after coupling of CQDs. The ·O 2 − was the dominant active specie to reduce Cr(VI), and possible mechanism was proposed. This work provides thought for design of high-performance photocatalysts by loading electron-collecting species to remove environmental pollutants .
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2022
·
IF 9.136
Wenbin Gao,Yan Tan,Binhai Wu,Yuzhen Chen,Zhan Hu,Yifan Wang,Yujiao Wen,Zhi Zhou,Nan Zhou
Quinclorac (QNC) and Cr(VI), are common contaminants in surface waters, posing serious hazard to human and ecological health. Nano FeS, an effective catalyst that has excellent redox properties, is susceptible to over-oxidation and agglomeration problems, which impede its practical application. Herein, nano-Fe 1−x S was modified by stable iron oxide (Fe 3 O 4 ) and biochar (BC AA /Fe 1−x S/Fe 3 O 4 ), which presented the core (Fe 1−x S) shell (Fe 3 O 4 )-like structure uniformly dispersed on BC AA surface. The composite overcame the disadvantages of nano-Fe 1−x S and achieved high removal efficiency of 100% and 99.98% for QNC and Cr(VI), respectively. Based on XPS analysis, Fe(II) content was reduced from 53.3% to 34.2% and S(II) content from 13.0% to 6.5%. Fe(II) species in the composite were the main active substance for QNC degradation and Cr(VI) reduction, and S(II) species also indirectly provided electrons to promote Fe 2+ /Fe 3+ cycling. Then, we identified the intermediates of QNC and active radicals • OH or SO 4 •− in the system to suggest possible degradation pathways. We further discovered no mutual interference between QNC and Cr(VI) and proposed the possible mechanism for simultaneous removal that QNC degradation by radical attack and Cr(VI) reduction by electrons.
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危险品化学品经营许可证（带存储）