Processes
·
2024
·Vol. 12
·期 5
·905
·
IF 2.8
Tianji Liu,Huawei Guo,Qing Yu,Yajun Wang,Huan Liu,Yanan Zeng,Yitong Wang,Chunyu Liu,Junguo Li
In this study,Chlorella pyrenoidosawas cultured with different concentrations of Cr(III) and Cr(VI), and the changes in biomass, lipid content, protein content and total sugar content ofChlorella pyrenoidosaunder different culture conditions were detected. The effects of Cr(III) and Cr(VI) on the intracellular antioxidant system and related key enzymes of lipid synthesis were analyzed. The results showed that appropriate Cr(III) and Cr(VI) concentrations could makeChlorella pyrenoidosaregulate the contents of SOD, POD, ASA, CAT and GSH in cells, improve the enzyme activity of ACC and promote lipid synthesis. The aim was to investigate the mechanism of lipid synthesis by analyzing the distribution of Cr(III) and Cr(VI) in algal cells. The lipid content ofChlorella pyrenoidosareached its highest level at 50.43 wt% and 38.00 wt% when both Cr(III) and Cr(VI) concentrations in the culture environment were 0.5 mg/L. These values were 1.37 and 1.03 times higher than the control group, respectively. The addition of appropriate Cr(III) and Cr(VI) concentrations can increase ME enzyme activity and decrease PEPC enzyme activity, shorten the biomass accumulation cycle and prolong the lipid synthesis cycle.
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JOURNAL OF CHROMATOGRAPHY A
·
2025
·
IF 4
Yonglin Liu,Shuran He,Hanfei Gao,Xinyi Wang,Qingjian Zhang,Wei Tian,Baorong Duan,Lin Liu
s The study investigated the removal of Cr(Ⅲ) and Cd(Ⅱ) by argillaceous limestone (AL) in a binary adsorption system. The results indicate that AL’s capacity to adsorb Cr(Ⅲ) is enhanced by the presence of Cd(Ⅱ). Conversely, the presence of Cr(Ⅲ) significantly decreases the adsorption of Cd(Ⅱ). The adsorption mechanisms involve precipitation, chelation, and ion exchange. AL’s adsorption behavior was well described by the pseudo-second-order kinetic model, suggesting that the adsorption process was dominated by chemical interactions and the monolayer adsorption pattern. The pH affects adsorption primarily by altering the protonation degree of the AL surface. In the single-component system, the maximum adsorption capacity for Cr(III) reached 30.98 mg·g⁻ 1 at pH 7.0, while that for Cd(Ⅱ) reached 38.80 mg·g⁻ 1 at pH 8.0. In the binary system, Cr(Ⅲ) achieved its highest adsorption capacity (42.56 mg·g⁻ 1 ) at pH 6.0, while Cd(Ⅱ) exhibited a maximum capacity of 19.16 mg·g⁻ 1 at pH 7.0. The presence of Na⁺ and Ca 2 ⁺ ions reduced the adsorption efficiency, with greater inhibition observed as ionic strength increased. This study clarifies the composite adsorption behavior of AL in multi-ion systems and can advance the direct application of natural minerals in environmental pollution remediation.
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DALTON TRANSACTIONS
·
2015
·Vol. 45
·期 20
·8347-8354
·
IF 4.197
Chen Dong,Genhua Wu,Zhuqing Wang,Wenzhi Ren,Yujie Zhang,Zheyu Shen,Tianhua Li,Aiguo Wu
A colorimetric assay is proposed for the selective detection of Cr(III) and Cr(VI) via the aggregation-induced color change of gallic acid capped gold nanoparticles (GA-AuNPs). The AuNPs are characterized using UV-vis spectroscopy, transmission electron microscopy (TEM), dynamic light scattering (DLS) and Fourier-transform infrared spectrometry (FT-IR). To detect Cr(III) and Cr(VI) coexisting in a sample, citrate and thiosulfate were applied to mask Cr(VI) for the detection of Cr(III), and ethylenediaminetetraacetic acid disodium salt (EDTA) was applied to mask Cr(III) for the detection of Cr(VI). At optimized experimental conditions, the selectivity of these AuNPs-based detection systems is excellent for Cr(III) and/or Cr(VI) compared with other types of metal ions. The limit of detections (LODs) of a mixture of Cr(III) and Cr(VI), Cr(III) and Cr(VI) by eye vision are 1.5, 1.5 and 2 μM, respectively, and those by UV-vis spectroscopy are 0.05, 0.1 and 0.1 μM, respectively. The minimum detectable concentrations for Cr(III) or Cr(VI) are all below the guideline value set by the US Environmental Protection Agency (EPA). The applicability of the AuNPs-based colorimetric sensor is also validated by the detection of Cr(III) and Cr(VI) in electroplating wastewater and real water samples with high recoveries.
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APPLIED CATALYSIS B-ENVIRONMENTAL
·
2017
·
IF 9.446
Yaxi Zhang,Mengjiao Xu,Hao Li,Hao Ge,Zhenfeng Bian
The photocatalytic reduction efficiency of hexavalent chromium (Cr 2 O 7 2− (Cr(VI)) is suffering from high recombination of photoinduced charges, poor adsorption capacity of Cr(VI), and slow desorption of product trivalent chromium (Cr 3+ (Cr(III))) from photocatalyst surface. In this work, carbon dots (CDs) was coupled with TiO 2 mesocrystals (MT), where CDs displayed both the electron collectors and the active sites. During photoreduction of Cr(VI), the as-prepared CD/MT exhibited activity about 5.4 times higher than the pure TiO 2 mesocrystals. The positive charges on the CD/MT surface favored the selective adsorption of Cr(VI) and rapid desorption of Cr(III), which has an obvious promotion on the photocatalytic reduction of Cr(VI) and retention of photoreduction activity. Meanwhile, the CDs coupled on TiO 2 mesocrystals facilitated the separation of photogenerated charges. This work provides a simple and effective adsorption-photoreduction-desorption mechanism for the photocatalytic reduction of Cr(VI).
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CHINESE CHEMICAL LETTERS
·
2013
·
IF 1.21
Bing Zhao,Ya-Cui Zhou,Meng-Jiao Fan,Zhi-Yu Li,Li-Yan Wang,Qi-Gang Deng
Three tetraaryl imidazole derivatives 5a–5c bearing thiazole groups were synthesized in the presence of [Bmin]Br by one-pot reaction and their structures were fully characterized by the 1 H NMR, IR, MS and elemental analysis. The results of UV–vis spectra and fluorescent spectra upon metal ions complexation show that compound 5a displays high selectivity and sensitivity for Cr 3+ ions. The complexation ratio of compound 5a and Cr 3+ is 1:1.
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Chemical Engineering Journal Advances
·
2025
·
IF 7.1
Wuxin Hou,Jizhuang Zuo,Yongle Gao,Yao Wang,Li Liu
The generation of humins by-products in biorefinery is often unavoidable. We here report the valorization of chitosan-derived humins for removal of heavy metal ions to enhance the atomic economy of the biomass conversion. Chitosan-derived humins were synthesized by catalysis of oxalic acid (OA), whereby the adsorption performance for Cd(II), Cr(III) and Cr(VI) was explored. The adsorption data were well fitted by the pseudo-second-order kinetic model, complemented by the Freundlich and Temkin isotherm models, revealing maximum adsorption capacities of humins for heavy metal ions as follows: 358.7 mg/g for Cr(VI), 152.6 mg/g for Cd(II), and 40.2 mg/g for Cr(III). The mechanistic studies revealed that the adsorption of Cd(II) and Cr(III) by humins mainly occurs through ion exchange (carboxyl groups) and surface complexation (hydroxyl, carbonyl, and amino groups). In comparison, the adsorption of Cr(VI) by humins involves electrostatic attraction, alongside ion exchange and surface complexation. After carbonization and activation, the specific surface area increased markedly, however the adsorption capacity decreased owing to reduced oxygen- and nitrogen-containing functional groups. Competitive adsorption studies, industrial wastewater experiments, and cyclic adsorption tests demonstrate that humins exhibit remarkable adsorption performance even in complex environments. This work highlights that chitosan-derived humins are promising adsorbents for the remediation of heavy metal ions.
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SURFACE & COATINGS TECHNOLOGY
·
2026
·
IF 6.9
Sitian Zhu,Zhigang Xu,Qiang Shen,Chuanbin Wang,Lianmeng Zhang
Trivalent chromium (Cr(III)) electrodeposition is regarded as an environmentally benign alternative to hexavalent chromium plating, but the protective performance of Cr(III)-ZrC composite coatings can be limited by ZrC nanoparticle agglomeration and non-uniform incorporation. In this work, the nonionic surfactant Synperonic F108 (SF) was introduced for the first time into a Cr(III)-ZrC composite electrodeposition system to regulate ZrC dispersion and improve coating uniformity and corrosion resistance. SF was proposed to form a steric stabilization layer on ZrC nanoparticles, and the dispersion results were consistent with reduced agglomeration and more homogeneous incorporation into the Cr(III) matrix. At an optimal SF concentration of 0.5 g/L, the dynamic light scattering (DLS)-measured median agglomerate size of ZrC decreased from 268 to 139 nm, and scanning Kelvin probe force microscopy (SKPFM) revealed the lowest surface-potential standard deviation of 9.04 mV, indicating improved dispersion and reduced local electrochemical heterogeneity. Consequently, compared with the SF-free coating, the corrosion current density of the 0.5 g/L SF coating decreased by 90.5%, from 5.39 to 0.51 μA·cm −2 , while its charge-transfer resistance increased to 69.7 × 10 4 Ω·cm 2 . Time-dependent electrochemical impedance spectroscopy and an 80-day scratched immersion test in 3.5 wt% NaCl solution further confirmed the superior long-term protective performance of the optimized coating. The enhanced performance is consistent with reduced agglomeration-induced defects, improved microstructural uniformity, and reduced local electrochemical heterogeneity, which may contribute to limiting preferential electrolyte ingress during long-term exposure. These findings demonstrate that surfactant-mediated dispersion regulation is an effective strategy for improving Cr(III)-based composite coatings.
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Journal of Environmental Chemical Engineering
·
2023
·
IF 7.7
Linshan Zhang,Guozong Yue,Luming Yang,Deshun Huang
Ultra-thin MXene nanosheets (Nss) were facilely prepared via delaminating and intercalating the multi-layered MXene using tetramethylammonium hydroxide (TMAOH). Electron-rich characteristics, abundant surface active sites and the negative charges made MXene Nss having both good reduction ability and adsorption capacities, which would effectively remove anion Cr(VI) via reduction and remove cation Cr(III) via adsorption. Batch adsorption tests were carried out to study the pH impact, adsorption kinetics and isotherms. Upon adsorption, the well dispersed MXene Nss suspension was aggregated to form flocs and sediment at the bottom. The maximum Cr(VI) and Cr(III) removing capacities are calculated to be 554.9 mg/g at 318 K and 283 mg/g at 298 K, respectively. The mechanisms on Cr(VI)/Cr(III) adsorption were well studied employing SEM, TEM , XPS and FT-IR. In addition, the MXene Nss also showed good adsorption capacity towards other metal cations (such as Cu 2+ , Cd 2+ , and Pb 2+ ), manifesting that the current MXene Nss has the potential to be used as a general-purpose adsorbent.
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Molecular Catalysis
·
2023
·
IF 4.6
Yi Liu,Shuangjiang Li,Xiaojian Yu,Ying Chen,Xiaoning Tang,Tianding Hu,Lan Shi,Manoj Pudukudy,Shaoyun Shan,Yunfei Zhi
For the simultaneous attainment of the utilization of renewable biomass resources and the mitigation of greenhouse effects, it is very promising to develop a green, recyclable, and highly efficient heterogeneous catalyst for the synthesis of cyclic carbonates by CO 2 cycloaddition reaction with epoxides. Herein, novel cellulose nanofibers (CNF) supported (Salen)Cr(Ⅲ) complex was effectively synthesized for the aforementioned reaction. The cellulose nanofibers (CNF) were firstly modified with (3-aminopropyl) triethoxysilane (APTES), and then its Schiff base with salicylaldehyde was synthesized, which further subjected to coordination treatment with chromium chloride to form a novel heterogeneous catalyst, labelled as CNF-(Salen)Cr(Ⅲ). The catalytic performance of the catalysts shown that CNF-(Salen)Cr(Ⅲ) and co-catalyst TBAB can synergistically catalyze the cycloaddition of CO 2 with epichlorohydrin (ECH) at mild reaction conditions, and the yield of chloropropene carbonate (CPC) reached up to 97.8% with high selectivity. The CNF-(Salen)Cr(Ⅲ) complex maintained high catalytic activity after six cycles of repeated runs and has acceptable catalytic effect on other series of epoxies. Based on density functional theory (DFT) calculations, a reaction mechanism including adsorption activation of epoxides, epoxides ring opening, CO 2 insertion, and the formation of cyclic carbonate, was proposed for the CNF-(Salen)Cr(Ⅲ) complex catalyzed cycloaddition of CO 2 with epoxides.
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ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2022
·Vol. 29
·期 30
·45623-45634
·
IF 5.19
Liang Linqing,Wang Jiahong,Tong Xinhao,Zhang Shutong
The Fe 3 O 4 @nSiO 2 @mSiO 2 /NTA (FNMs-NTA) was prepared by grafting magnetic mesoporous microspheres with nitrilotriacetic acid (NTA) and applied as an adsorbent for the removal of Cr(III) from complex solutions. Some characterization techniques including Brunauer–Emmett–Teller (BET), Fourier transform infrared spectrometer (FT-IR), X-ray diffraction (XRD), small-angle X-ray diffraction (SAXS), vibrating sample magnetometer (VSM), and thermal gravimetric analysis (TGA) were used to characterize functional groups and pore structure of FNMs-NTA, which proved that NTA was successfully decorated onto the magnetic Fe 3 O 4 @nSiO 2 @mSiO 2 (FNMs) and FNMs-NTA featured a regular mesoporous structure. The batch adsorption of Cr(III) by FNMs-NTA exhibited high adsorption capacity (16.0 mg·g −1 at pH 3.0, and 25 °C). Adsorption data followed Freundlich isotherm and adsorption process was a spontaneous adsorption process. Moreover, the kinetics of adsorption were well explained by pseudo-second-order kinetic model. FNMs-NTA showed resistance to interfering inorganic cations (Na + , Ca 2+ ) and complexing agents (EDTA). Furthermore, FNMs-NTA exhibited remarkable regeneration performance and easy separation under external magnetic field. X-ray photoelectron spectroscopy (XPS) analysis showed the FNMs-NTA had excellent adsorption ability for Cr(III) because of the ion exchange and surface complexation.
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JOURNAL OF MOLECULAR LIQUIDS
·
2023
·
IF 6
Guang Tian,Xiangxiang Li,Falin He,Shuqi Guo,Yaoyue Wang,Yuze Li,Wansong Zong,Rutao Liu
Chromium (Cr) poses potential threats on human and ecological health through both food and environmental pathways. However, the response mechanisms of Cr to function-related proteins in human subjects and the differential effects in the case of different valence states of Cr are still lacking. Herein, the binding interactions and mechanisms of lysozyme to Cr(III) and Cr(VI) were investigated by isothermal titration microcalorimetry, multi-spectroscopy, enzyme activity assay, and molecular simulations. Our results indicated that the binding of Cr in different valence states with lysozyme was a relatively affinity process and mainly driven by hydrophobic forces. Both Cr species induced the looseness of backbone for lysozyme and the enhancement of hydrophilicity around the backbone microenvironment. Otherwise, the α-helix of lysozyme was decreased with different valence states of Cr, while Cr(III) showed a greater degree of influence and a stronger regularity. Interestingly, no significant changes in the microenvironment around aromatic amino acid residues were observed under the exposure of different valence states of Cr. Differential structural changes of lysozyme resulted in activity alterations. At 80 mg·L −1 of Cr, Cr (VI) reduced the lysozyme activity to 81.44% of the control, while the lysozyme activity was significantly reduced to 24.45% under the exposure of Cr (III). Further molecular docking showed that amino acids near the binding sites of different valence states of Cr with lysozyme were not identical, but the enzyme active site, Asp52, was all within the binding pocket. This study elucidates the differential toxicity effects and interaction mechanisms of Cr in different valence states, and offers a comprehensive strategy for exploring the in vitro responses of toxicants exposure.
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RSC Advances
·
2020
·Vol. 10
·期 46
·27775-27787
·
IF 3.119
Qining Liu,Honghui Liu,Huixia Chen,Xinrun Wang,Dahai Hu,Xichuan Cheng,Hongbin Xu
In this paper, the reoxidation behaviours of CrOOH and Cr(OH)3 are investigated as the major reduction products of Cr(VI). The atmosphere oxidation of Cr(III) is studied in the environment of soil without manganese and hydrogen peroxide. The influence of temperature and pH value on the oxidation rate of Cr(III) is examined by Experiment methods in details. According to the experimental results, the oxidation of Cr(III) is promoted in the environment with high pH value, however, the oxidation process is stable with temperature. The oxidation process of CrOOH and Cr(OH)3 are theoretically researched by thermodynamic calculation and density functional theory (DFT) simulation. The results of DFT indicate that both CrOOH and Cr(OH)3 are oxidized during the chemical adsorption process of O2 in alkaline environment. With the transformation from Cr(III) to Cr(VI), the Cr–O covalent bond forms in the adsorption process. The crystal structure difference between CrOOH and Cr(OH)3 leads to the different oxidation reaction between O2 and Cr(III). The significant alteration of oxidation process in (110), (310), (321) crystal planes is also observed indicating the crystal orientation dependence. Based on the chemical reaction kinetics, the chemical equivalent constant K of CrOOH is higher than Cr(OH)3, illustrating higher chemical stability in air. In summary, both experimental study and theoretical analysis on the reoxidation phenomenon of Cr(III) reduced from Cr(VI) in natural environment demonstrate that not only the external factors such as temperature and pH value but also the crystal structure of Cr(III) compound have dramatic influence on the oxidation process.
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