Journal of Cleaner Production
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2019
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IF 6.395
Song Gao,Qinze Liu,Qiang Liu,Chengbing Yuan,Tingting Gao,Jinshui Yao
In this work, hollow globular Cr(VI)-adsorbents were successively fabricated via the assembly of tannic acid (TA) and 1, 6-hexanediamine (HA) converting to polymerization using polyvinyl alcohol (PVA) as precursor. PVA@poly(tannic acid - 1, 6-hexanediamine) (PVA@PTHA) with hollow structure can chelate Cr on their bodies accompanying of reduction of Cr(VI) to Cr(III) caused by phenolic hydroxyl groups, which is proved by means of TEM , XPS , SEM and EDX, etc . Many factors affecting the adsorption of Cr(VI) were studied systematically, i.e. , initial Cr(VI) concentration (20–260 mg/L), contact time (0–48 h), foreign ions (Cu 2+ , Fe 3+ , Mn 2+ ), and pH value (2–7). The adsorption-reduction process followed the Langmuir isotherm model (R 2 = 0.9994) and fitted well with the pseudo-second-order kinetic model (R 2 = 0.9984). Besides, the removal capabilities of PVA@PTHA for Cr(VI) were affected insignificantly by nitrate ion (NO 3 − ) or sulfate ion (SO 4 2− ) as a competitive ion. In brief, PVA@PTHA is low-cost green adsorbent with the maximum adsorption capacity of 434.0 mg/g for Cr(VI)-sewage treatment.
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NEW JOURNAL OF CHEMISTRY
·
2019
·Vol. 43
·期 13
·5039-5046
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IF 3.069
Yao Chen,Shihao Xu,Shuai Han,Suyun Chu,Liang Yang,Changlong Jiang
Poly(m-phenylenediamine) (PmPD) is an efficient material for the adsorption of Cr(VI). However, it is facile to aggregate in water, which reduces its adsorption capacity, and it is not facile to be separated from water. Hence, magnetic or membrane structures by compositing PmPD with other functional materials are usually synthesized to solve the above problems. Here, we utilized polyvinyl alcohol (PVA) chains to obtain a dense network structure, which embedded and constrained PmPD into the network to form a membrane. PmPD constrained in the membrane existed stably and was facilely separated from water due to the large size of the membrane. Meanwhile, the PmPD/PVA membranes showed good mechanical properties and combined both the extraordinary adsorption capacity and reusability. In this study, the maximum Cr(VI) adsorption capacity of the composite membrane structures was 498.87 mg g−1 at room temperature. The adsorption and removal mechanism can be explained by the fact that the protonated imine units adsorb Cr(VI) via electrostatic attraction; following this, Cr(VI) changed to Cr(III) by reduction and chelated on the imine units. This study demonstrated that the PmPD/PVA membrane has a great potential for the separation of Cr(VI) from wastewater due to its low-cost and high adsorption capacity.
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ACS Earth and Space Chemistry
·
2019
·
IF 2.243
Zhipeng Shu,Lihu Liu,Guohong Qiu,Xiong Yang,Mingzhe Zhang,Wenfeng Tan,Chengshuai Liu,Fei Wu
The formation and transformation of schwertmannite affect the migration, conversion, and toxicity of chromium (Cr) in soils and sediments. Schwertmannite could be obtained from the oxidation of Fe(II) by hydroxyl radicals (OH•) and superoxide radicals (O2•–) generated from the photolysis of NO3– under acidic and sulfate-rich conditions. As one of the most abundant components, montmorillonite is widely distributed in soils and sediments. However, the effect of montmorillonite on the photochemical formation process and corresponding Cr adsorption behaviors of schwertmannite remains elusive. This study indicates that schwertmannite could be formed on the montmorillonite surface during the photocatalytic oxidation of dissolved Fe(II). The formation rate, particle size, and crystallinity degree of schwertmannite formed on montmorillonite surface increased with increasing FeSO4 concentration (1.0–5.0 mmol L–1). The presence of montmorillonite led to a decrease in the particle size of schwertmannite. When the initial concentration of Fe(II) was 5.0 mmol L–1, the specific surface area of schwertmannite–montmorillonite aggregates reached 243.3 m2 g–1, which was remarkably larger than that of single-phase schwertmannite (24.6 m2 g–1) and montmorillonite (138.1 m2 g–1). The schwertmannite–montmorillonite aggregates showed a higher adsorption capacity for Cr(VI) (97.4 mg Cr g–1 Fe) than single-phase schwertmannite (72.9 mg Cr g–1 Fe). This work reveals the possible formation pathway and Cr adsorption behavior of schwertmannite on the surface of montmorillonite in waters and soils.
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CARBOHYDRATE POLYMERS
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2019
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IF 6.044
Jinfeng Mei,Hui Zhang,Zhongyu Li,Hongxiang Ou
A kind of water-soluble chitosan, chitosan oligosaccharide, was used to synthesize a crosslinking hydrogel using a simple method, and the outstanding adsorption property of the hydrogel for Cr(VI) was investigated. The three-dimensional structure of the synthetic material was analyzed by means of 13 C solid state nuclear magnetic resonance (NMR), Fourier transform infrared (FT-IR), X-ray diffraction (XRD) and Scanning Electron Microscope (SEM) measurements. The hydrogel also exhibited high thermal stability and mechanical strength. Its adsorption capacity for Cr(VI) reached 148.1 ± 2.4 mg/g with a fast adsorption rate. Pseudo-second-order kinetic model and Langmuir isotherm well described the adsorption process. Notably, the hydrogel still showed 100% removal efficiency for Cr(VI) at low concentration (0.02–1 mg/L) in the detectable range. The simple preparation process, high mechanical strength and excellent adsorption property indicate that the hydrogel has great potential for the removal of Cr(VI) ions from water and wastewater.
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PubMed
高影响因子
NEW JOURNAL OF CHEMISTRY
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2018
·Vol. 42
·期 11
·9006-9015
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IF 3.201
Huating Sun,Tianxing Wu,Yunxia Zhang,Dickon H. L. Ng,Guozhong Wang
Molybdenum disulfide (MoS2) was successfully synthesized via a facile one-step hydrothermal method without addition of templates or surfactants. The obtained MoS2 product was characterized via various techniques including FESEM, HRTEM, XRD, BET and XPS analyses. Their application in capturing Cr(VI) ions in water was investigated. The results showed that the MoS2 nanosheets were ultrathin with a thickness of 5–10 nm and had a uniform lateral size of 100–200 nm. Impressively, these MoS2 nanosheets not only possessed enlarged interlayer spacing, but also had multiple defects on the basal planes, which were proved to be crucial in the removal of Cr(VI). The kinetics of chromium adsorption was found to follow the pseudo-second-order rate equation and the adsorption isotherm data were well fitted to the Langmuir model with a chromium in-take capacity of about 84.03 mg g−1. This structure-enhanced removal was likely related to the synergism of adsorption and reduction, in which the anionic Cr(VI) was adsorbed on the surface of D-MoS2via electrostatic interaction. At the same time, some fraction of the adsorbed Cr(VI) was reduced to low toxic Cr(III) and the generated Cr(III) species were adsorbed by the adsorbent. More significantly, the adsorption and reduction processes not only transferred the Cr(VI) from the aqueous environment to the surface of solid adsorbents but also alleviated the toxicity of Cr(VI). It was evident that this study may promote the application of other transition metal dichalcogenides in environmental remediation.
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APPLIED CATALYSIS B-ENVIRONMENTAL
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2018
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IF 11.698
Xue Bai,Yanyan Du,Xiaoyun Hu,Yudong He,Chunliang He,Enzhou Liu,Jun Fan
A novel RP-MoS 2 /rGO nanocomposite as low-cost, environmental sustanable, stability and high-performance photocatalyst was successfully fabricated for the first time through a facile two-step hydrothermal method. Even without a noble-metal cocatalyst, the introduction of MoS 2 /rGO hybrid made RP exhibit excellent photocatalytic performance, including photoreduction of Cr (VI) and photooxidation of different organic pollutants, owing to the increased number of excited electrons/holes and enhanced separation efficiency of charge carriers. Importantly, the synergy of photocatalytic reduction and oxidation, as well as photocatalysis and adsorption played an important role in enhancing photocatalytic activity and reaching a high efficiency. Besides, the chemical structure of the RP-MoS 2 /rGO with P–S and P O bands ensure the stability of the nanocomposite materials. Overall, the photocatalytic elimination of the Cr (VI)-Organic molecule coexistence system in this work shows promising application to treatment the reality wastewater.
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SCIENCE OF THE TOTAL ENVIRONMENT
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2019
·
IF 5.589
Xu Yan,Mengmeng Song,Mo Zhou,Chunlian Ding,Zhongren Wang,Yunyan Wang,Weichun Yang,Zhihui Yang,Qi Liao,Yan Shi
CuO nanoparticles (NPs) released into aqueous environments induce metal toxicity, which generally exerts negative effects on various organisms and leads to great challenge for wastewater biotreatment. In this study, a promotion effect of CuO NPs on biological process was first found. Cr(VI) reduction by Cupriavidus basilensis B-8 (hereafter B-8) was enhanced in the presence of CuO NPs. The efficiency of Cr(VI) bioreduction was much higher with B-8 and CuO NPs (approximately 100%) than with B-8 (approximately 37.6%) and CuO NPs (39.9–44.7%) alone, indicating a stimulatory effect of CuO NPs on Cr(VI) reduction by B-8. Our material analyses revealed different response mechanisms of B-8 to Cr(VI), with and without CuO NPs. The addition of CuO NPs influenced the interaction of Cr(VI) with the N-, P-, S-, and C-related functional groups of B-8. Transcriptomic analysis indicated that multiple mechanisms, including Cr(VI) uptake and reactive oxygen species detoxification, were induced by Cr(VI). Many genes involved in various metabolic processes were significantly upregulated by the addition of CuO NPs. To a certain extent, the pressure of DNA repairment by B-8 induced by Cr(VI) was also alleviated by the presence of CuO NPs. They contributed to facilitate B-8 growth and enhance Cr(VI) reduction, even with 50 mg/L Cr(VI). This study not only elaborated the mechanisms of bacterial Cr(VI) reduction when enhanced by CuO NPs, but also provided a novel perspective for wastewater biotreatment.
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Journal of Energy Chemistry
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2014
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IF 0
Yong Xie,Rui-Xia Yang,Nian-Yu Huang,Hua-Jun Luo,Wei-Qiao Deng
We reported a bifunctional material, Cr-salen implanted conjugated microporous polymer (Cr-CMP), which is able to capture excellent CO 2 amounts and has a remarkable catalytic activity towards the cycloaddition reaction of CO 2 to epoxides forming cyclic carbonates at mild conditions without additional solvents. This heterogeneous Cr-CMP catalyst has a superior catalytic activity to its related homogeneous catalyst and can be reused more than ten times without a significant decrease in catalytic activity.
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Journal of Materials Chemistry A
·
2015
·Vol. 3
·期 12
·6586-6591
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IF 7.443
Hongfei Shi,Huaqiao Tan,Wan-bin Zhu,Zaicheng Sun,Yuejia Ma,Enbo Wang
A series of Cr-doped Bi4Ti3O12/Bi2Ti2O7 (BTO) heterostructure fibers have been synthesized via a one-step, facile and economical electrospinning/calcination process. SEM and TEM results reveal that the diameters of the as-prepared fibers are 100 ± 30 nm. The light adsorption of Bi4Ti3O12 and Bi2Ti2O7 in the fibers has been remarkably improved by Cr doping. With increased Cr doping, XRD and XPS show that the amount of Bi2Ti2O7 increases in the fibers. As a result, the Bi4Ti3O12/Bi2Ti2O7 heterojunction structure is enhanced, which further promotes the charge separation of photogenerated charge carriers. Photocatalytic tests indicated that the as-prepared Cr-doped Bi4Ti3O12/Bi2Ti2O7 fibers exhibit good photocatalytic activity for photodegradation of methyl orange (MO) under visible-light irradiation.
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JOURNAL OF ELECTROANALYTICAL CHEMISTRY
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2015
·
IF 2.729
Xiuli Song,Tailai Yang,Haiyan Du,Wenyan Dong,Zhenhai Liang
Transition metal mixed oxides of Mn and Cr with the nominal compositional formula Mn x Cr 1 − x O 1.5 ( x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0) were obtained by the thermal decomposition method. The powders were analyzed by SEM (scanning electron microscopy), XRD (X-ray diffraction) and XPS (X-ray photoelectron spectroscopy). The electrochemical properties of the Mn x Cr 1 − x O 1.5 electrodes for the OER (oxygen evolution reaction) in alkaline solution were evaluated by LSV (linear sweep voltammetry), staircase voltammetry and chronoamperometry . The results indicated that the mixed oxides were solid solutions of Mn 2 O 3 (bixbyite) and Cr 2 O 3 (eskolaite), and when x = 0.2, the catalyst had better catalytic activity in the OER process than did that of single Mn 2 O 3 and Cr 2 O 3 . At the high potential region (1.0 V vs Ag/AgCl), the current density of the Mn 0.2 Cr 0.8 O 1.5 electrode was ~ 80 times higher than that of Mn 2 O 3 and ~ 9 times higher than Cr 2 O 3 , and its overpotential ( η = 367.3 mV at a current density of 1.0 mA·cm − 2 ) was considerably lower than that of single Mn 2 O 3 ( η = 996.5 mV) and Cr 2 O 3 ( η = 648.5 mV) catalysts and was comparable to the precious metal oxide IrO x . The stability testing indicated that the mixed oxides had good stabilities in strong alkaline solution during the OER process.
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APPLIED CATALYSIS A-GENERAL
·
2014
·
IF 3.674
Siyang Tang,Zhen Liu,Xiaowei Yan,Ning Li,Ruihua Cheng,Xuelian He,Boping Liu
An extensive experimental kinetic study of ethylene trimerization was carried out over the Chevron-Phillips homogeneous catalyst system [Cr(2-ethylhexanoate) 3 (Cr(2-EH) 3 )/2,5-dimethylpyrrole (DMP)/co-catalyst/halide] in terms of the effects from organic halide additives, type of co-catalysts, temperature, ethylene pressure, Cr concentration, and ligand/Cr molar ratio, etc. Ten kinds of organic halides and four kinds of organometallic co-catalysts were tested in this work. The 1,1,2,2-tetrachloroethane (TCE) and triethylaluminum (TEA) were found to be the best candidates for this catalyst system. The molar ratios of DMP/Cr, TCE/Cr and TEA/Cr showed a strong impact on the catalytic performance of ethylene trimerization. A detailed catalytic kinetic behavior and the kinetic simulation were also performed for the first time over this catalyst system. It could be extrapolated that the dependency of the trimerization reaction rate on ethylene concentration and catalyst concentration is second-order and first-order, respectively. The apparent activation energy of this reaction is 99.1 kJ/mol at the temperature range from 65 °C to 95 °C. And the apparent reaction rate equation is achieved as follows:. R = 5.23 × 10 18 exp − 99.1 R T C ca 1.12 C e 1.95 .
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SENSORS AND ACTUATORS B-CHEMICAL
·
2014
·
IF 3.84
Wangyao Zhang,Yang Yang,Fenfen Li,Guosheng Song,Yong Shao,Ruizhuo Ouyang,Lina Xu,Weiwei Li,Yuqing Miao
A simple one-step method was successfully developed to prepare stable nanosized Ni(OH) 2 @Cr(OH) 3 hybrid particles by just adding NaOH to a mix solution containing Ni(NO 3 ) 2 and Cr(NO 3 ) 3 at room temperature. In contrast, under the exact same conditions, flocculent Ni(OH) 2 or Cr(OH) 3 precipitate was obtained after the addition of equivalent NaOH in a solution containing same amount of Ni(NO 3 ) 2 or Cr(NO 3 ) 3 as in the mix solution. The interaction between Ni(II) and Cr(III) ions was believed to make major contribution to the formation of stable Ni(OH) 2 @Cr(OH) 3 nanohybrid without aggregation to large-size particles. The prepared Ni(OH) 2 @Cr(OH) 3 hybrid nanoparticles were well characterized by the scanning electron microscopy (SEM), the transmission electron microscopy (TEM), X-ray diffraction (XRD), and electrochemical measurements with results showing uniform size, smooth surface, good monodispersibility, fast electron transfer rate as well as promising electrocatalytic properties toward glucose (Glu) and cysteine (Cys) oxidation. The presence of a small amount of Cr(OH) 3 in the composite not only improved the stability and monodispersibility of the Ni(OH) 2 @Cr(OH) 3 hybrid particles, decreased their size to nanoscale, but also exerted positive effect to the electrochemical properties of the obtained Ni(OH) 2 based nanomaterials like the electron transfer rate and the electrocatalytic activity. Satisfactory electrocatalytic performances of the Ni(OH) 2 @Cr(OH) 3 nanohybrid toward Glu and Cys oxidations were achieved, respectively, in certain concentration ranges with acceptable detection limits and correlation coefficients, suggesting the potential facilitation of electrocatalysis toward other small molecules by the newly prepared Ni(OH) 2 @Cr(OH) 3 nanohybrid.
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