ELECTROCHIMICA ACTA
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2013
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IF 3.777
Ruizhuo Ouyang,Wangyao Zhang,Shilin Zhou,Zi-Ling Xue,Lina Xu,Yingying Gu,Yuqing Miao
We report here the successful fabrication of an improved Bi film wrapped single walled carbon nanotubes modified glassy carbon electrode (Bi/SWNTs/GCE) as a highly sensitive platform for ultratrace Cr(VI) detection through catalytic adsorptive cathodic stripping voltammetry (AdCSV). The introduction of negatively charged SWNTs extraordinarily decreased the size of Bi particles to nanoscale due to electrostatic interaction which made Bi(III) cations easily attracted onto the surface of SWNTs in good order, leading to higher quality of Bi film deposition. The obtained Bi/SWNTs composite was well characterized with electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), the static water contact angle and the voltammetric measurements. The results demonstrate the improvements in the quality of Bi film deposited on the surface of SWNTs such as faster speed of electron transfer, more uniform and smoother morphology, better hydrophilicity and higher stripping signal. Using diethylene triaminepentaacetic acid (DTPA) as complexing ligand, the fabricated electrode displays a well-defined and highly sensitive peak for the reduction of Cr(III)–DTPA complex at −1.06 V (vs. Ag/AgCl) with a linear concentration range of 0–25 nM and a fairly low detection limit of 0.036 nM. No interference was found in the presence of coexisting ions, and good recoveries were achieved for the analysis of a river sample. In comparison to previous approaches using Bi film modified GCE, the newly designed electrode exhibits better reproducibility and repeatability toward aqueous detection of trace Cr(VI) and appears to be very promising as the basis of a highly sensitive and selective voltammetric procedure for Cr(VI) detection at trace level in real samples.
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高影响因子
Journal of the Taiwan Institute of Chemical Engineers
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2017
·
IF 4.217
Ran Li,Qing-Da An,Bing-Qi Mao,Zuo-Yi Xiao,Shang-Ru Zhai,Zhan Shi
Employing mussel-inspired concept, a controllable “Sol-Gel-like” condensation of dopamine (DA) and aminosilane coupling agents (A1, A2, A3 represent APTMS, TSPED and TPDA, respectively) was undertaken to synthesize magnetic hollow composites (Fe 3 O 4 @A/PDA), aiming for removing Cr(VI) from wastewater. Compared to reported magnetic amino-functionalized composites for heavy metal removal, it is a new green process via post-grafting pathways that can avoid using organic solvents and high-temperature treatment. Structural characterization and batch experiments are correlated to illustrate the adsorption performance of resultant composites. Upon screening resultant adsorbents, Fe 3 O 4 @A2/PDA exhibited the highest adsorption capacity; the maximum Cr(VI) removal amount could be up to 284.1 mg g −1 at 298 K and pH 2.0. The pseudo-second-order and Langmuir model preferably fitted the adsorption process , besides, the activation energy is 7.17 kJ/mol −1 . The hollow composites could be easily separated from solutions by a magnet, and over 70% Cr(VI) could be removed even after five cycles. Electrostatic attraction and reduction reaction could be used to explain the adsorption mechanism that on the basis of XPS analysis. According to thermodynamic analysis, the adsorption is a spontaneous endothermic process. The high Cr(VI) adsorption capacity, fast adsorption kinetics and easy separation properties of hollow Fe 3 O 4 @A2/PDA composites make it be potential to alleviate Cr-containing aqueous solutions.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2016
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IF 3.782
Nannan Qin,Ya Zhang,Hongjian Zhou,Zhigang Geng,Gang Liu,Yunxia Zhang,Huijun Zhao,Guozhong Wang
The reactivity of zero valent iron (Fe 0 ) for removing Cr(VI) is self-inhibiting under neutral and alkaline conditions, due to the precipitation of ferrous hydroxide on the surface of Fe 0 . To overcome this difficulty, we incorporated a second metal (Co) into Fe 0 to form FeCo bimetallic nanoparticles (FeCo BNPs), which can achieve higher activity and significant improvement in the reaction kinetics for the removal of Cr(VI) compared with Fe 0 . The FeCo BNPs were synthesized by a hydrothermal reduction method without using any templates. The characterization analysis indicated that the products were highly uniform in large scale with 120–140 nm size in diameter. The obtained FeCo BNPs exhibited a remarkable removal ability for Cr(VI) in the pH range of 5.3–10.0. Especially, FeCo BNPs were able to reduce trace Cr(VI) (1.0 mg L −1 , pH = 7.5) down to about 0.025 mg L −1 within 1 h. XPS analysis confirmed that Cr(VI) was reduced to Cr(III) by FeCo BNPs, while Fe and Co was oxidized, implying a chemical reduction process. The enhanced removal of trace Cr(VI) could be originated from the introduction of Co, which not only served as a protecting agent against surface corrosion by galvanic cell effect, but also enhanced the efficient flow of electron transfer between iron and Cr(VI). All the results primarily imply that FeCo BNPs can be employed as high efficient material for wastewater treatment.
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FUEL PROCESSING TECHNOLOGY
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2016
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IF 3.847
Ting-Ting Zhao,Wen-Zhi Ge,Fen Yue,Ying-Xiong Wang,Christian Marcus Pedersen,Fan-Gui Zeng,Yan Qiao
Lignite showed high capacity for reducing Cr(VI) to Cr(III) and hence removed Cr(VI) from aqueous solution, but the reduced Cr(III) cannot be released from adsorbent afterwards especially under acidic condition. In order to know why Cr(III) ions are immobilized within lignite adsorbent and how to recovery Cr species, the interaction of Cr(III) ions with lignite oxidized by Cr(VI) was studied by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). The data obtained from these studies indicate that Cr(III) ions are bonded to oxygenic functional groups in lignite oxidized by Cr(VI) and electrons are delocalized over -O-Cr-O- domain. It is also revealed that the O atoms of C = O and C-O groups in the adsorbent matrix are bonded to Cr(III) ions along with the decrease of electron density, while the O atoms of O -C = O group are along with the increase of electron density. Based on these important structural information, we developed a method to treat Cr-loaded lignite further and to recover the Cr species.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2016
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IF 3.782
Jiabai Cai,Xueqing Wu,Fengying Zheng,Shunxing Li,Yaling Wu,Yanping Lin,Liting Lin,Biwen Liu,Qiaoying Chen,Luxiu Lin
After polystyrene@titanium dioxide (PS@TiO 2 ) composite with different size was calcined at designated temperature, TiO 2 hollow sphere with controllable size was obtained for high efficient photo-reduction of Cr(VI). The feature of the TiO 2 hollow sphere was investigated by SEM, TEM , XRD , UV–Vis, and photoluminescence . The photo-reduction of Cr(VI) were measured for the performance assessment of the TiO 2 hollow sphere, Cr(VI) was used as an electron acceptor . After irradiation for 2 h, the photo-reduction rate of Cr(VI) (pH = 2.82) for TiO 2 (450 nm) was 96%, which exhibited an increase of 5% and 8% compared with TiO 2 (370 nm) and TiO 2 (600 nm). The absorption edges of TiO 2 hollow sphere (450 nm) was largest with the increasing of hollow sphere size from 370 to 600 nm. The optimal hollow sphere size of TiO 2 was 450 nm for the photo-reduction of Cr(VI), because the light-harvesting efficiency (the best of absorption edge) and photo-generated electron-hole separation rate (the best of photo-reduction rate) of TiO 2 hollow sphere were controlled by its hollow sphere size. In addition, we find that the behavior of the hydrogen production was inhibited by the coexistence Cr(VI) solution. This study can improve our understanding of the mechanism for the activity enhancement by the optimal hollow sphere size of TiO 2 .
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Journal of Environmental Chemical Engineering
·
2024
·
IF 7.4
Haowen Zou,Wenqiang Xu,Shuaixuan Ying,Shichao Cai,Bo Chen,Ping Wang,Zhongkuan Wu,Feng He
Mechanochemically sulfidated microscale zero valent iron (S-mZVI bm ) exhibits promising Cr(VI) removal performance but is prone to be passivated by Cr(VI), how to mitigate the passivation is still a challenge. In this study, we successfully synthesized phthalic acid (PA, carboxyl-rich organic acid) modified S-mZVI bm particles (PA-S-mZVI bm (4:1)) through ball milling. The pre-corrosion of the ZVI surface by PA effectively increased the specific surface area of ZVI. Additionally, the carboxyl groups complexed with Cr(VI), thereby enhancing its Cr(VI) removal capacity and alleviating the passivation. The Cr(VI) removal by PA-S-mZVI bm (4:1) was mainly a chemisorption process on the surface and its Cr(VI) removal capacity (55.47 mg/g) was 1.26 and 9.94 – 14.83 times that of PA-mZVI bm and S-mZVI bm , respectively. The electron efficiency of Cr(VI) removal by both PA-S-mZVI bm (4:1) and S-mZVI bm was ∼100 %, however, the Fe(0) utilization efficiency of PA-S-mZVI bm (4:1) was at least 15 times higher than that of S-mZVI bm , explaining the superior performance of PA-S-mZVI bm (4:1). This study confirmed that PA modification could effectively mitigate the passivation and improve the Fe(0) utilization efficiency of S-mZVI bm .
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RSC Advances
·
2024
·Vol. 14
·期 39
·28320-28331
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IF 3.9
Linjie Yi,Hongwei Wang,Xianliang Ren,GaoBin Liu,Hongen Nian,Zhiqin Zheng,Fang Wu
Structural modification is expected to be a facile way to enhance the adsorption performance of MXene. In this work, the structural modification of Ti3C2Tx was carried out by a spray freezing method, and two kinds of nano-structure (spherical and flaky) of Ti3C2Tx were prepared by adjusting the solution concentration of Ti3C2Tx. Then the Cr(VI) adsorption capacity and removal efficiency of the spherical and flaky Ti3C2Tx was investigated, respectively. It is found that flaky Ti3C2Tx was produced with a Ti3C2Tx concentration of 3 mg mL−1, while spherical Ti3C2Tx was obtained with a concentration of 6 mg mL−1. The long diameter of flaky Ti3C2Tx is about 8–10 μm, and the specific surface area is 17.81 m2 g−1. While spherical Ti3C2Tx had a diameter of about 1–4 μm and a specific surface area of 17.07 m2 g−1. The optimized structure of flaky and spherical Ti3C2Tx improves the maximum adsorption capacity by 97% and 33%, respectively, compared with the few-layer Ti3C2Tx. The maximum adsorption capacity of flaky Ti3C2Tx was 928 mg g−1, while that of spherical Ti3C2Tx was 626 mg g−1. The adsorption capacity of both Ti3C2Tx structures decreased with the increase of pH, and reached the maximum value at pH = 2; meanwhile, the adsorption capacity of both Ti3C2Tx structures increased with the increase of Cr(VI) concentration. The adsorption of Cr(VI) on flaky Ti3C2Tx was very fast, reaching equilibrium in 3 min, while spherical Ti3C2Tx took 5 min. The adsorption of Cr(VI) on both Ti3C2Tx structures belonged to the monolayers, heat-absorbing chemical adsorption, and the diffusion process of Cr(VI) was regulated by the external diffusion and internal diffusion of particles. Its adsorption mechanism was the combination of reductive adsorption and electrostatic adsorption.
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ACS ES&T Engineering
·
2024
·
IF 7.4
Kai He,Yuanfang Lai,Shuchen Wang,Li Gong,Feng He
Metal doping for improving the reactivity of zerovalent iron (ZVI) has been well studied, while Mn(II)-modified microscale ZVI (Mn-mZVI) has not yet been explored. Herein, ball-milled Mn-mZVI was fabricated and used for Cr(VI) removal. Characterization analysis showed that the structure, composition, and charge of mZVI changed after the Mn(II) modification. The comparative test showed that Mn-mZVI could remove 100% of Cr(VI) within 10 min, whereas mZVI removed negligible Cr(VI) within 60 min. The zeta-potential and electrochemical evidence verified that the enhanced electrostatic attraction and electron-transfer ability contributed to the superior Cr(VI) removal performance of Mn-mZVI. Moreover, the solution pH increase caused the decline of Cr(VI) removal, and the presence of NO3– inhibited Cr(VI) removal, whereas other coexisting ions showed little influence on the Cr(VI) removal performance of Mn-mZVI. Chemical and material characterization analyses revealed that Cr(VI) reduction by Mn-mZVI was the combined action of Fe(0) and generated Fe(II). In addition, the reusability of Mn-mZVI was not ideal due to the surface passivation and loss of Mn(II), but the reactivity could be reactivated by ball-milling the reacted Mn-mZVI again with Mn(II). Overall, this work provides a new mentality for mZVI modification and is important to develop promising mZVI-based materials for Cr(VI) pollution control.
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Journal of Materials Chemistry C
·
2018
·Vol. 6
·期 8
·2088-2094
·
IF 5.976
Xiran Shen,Xudong Yang,Chunyan Su,Jinghua Yang,Long Zhang,Binghui Liu,Siyu Gao,Fangyuan Gai,Zhubao Shao,Guanghui Gao
Stimuli-sensitive nanocomposites have received special attention because of their potential applications in various fields. In this work, we report a novel thermo-responsive photoluminescent silver clusters/hydrogel nanocomposite with red emission, as a probe for highly sensitive and selective detection of Cr(VI) in aqueous solutions. The hydrogel nanocomposites integrate the advantages of p(NIPAM-co-AAc) hydrogel submicron particles and Ag clusters: the p(NIPAM-co-AAc) hydrogel submicron particles can act as templates for Ag nanoclusters and exhibit thermo-responsive properties. In addition, Ag nanoclusters endow excellent photoluminescent properties to our nanocomposites, resulting in photoluminescent sensors. As a result, we obtained novel thermo-responsive Ag clusters/p(NIPAM-co-AAc) hydrogel nanocomposites through photoreduction process. The photoluminescence (PL) intensity of as-prepared nanocomposites exhibited a linear and reversible response from 2 to 85 °C and displayed a high PL quenching for the sensitive and selective detection of Cr(VI), rather than Cr(III). The limit of detection could reach as low as 1 ppb, which indicates that it is an ideal sensor tool for environmental monitoring, laboratory detections and various other applications.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Liqing Zhang,Bo Li,Yonggang Wei,Haoyuan Xu
Environmental problems caused by Cr(VI) need to be solved urgently. As a green and safe adsorbent, magnesium oxide has the characteristics of strong adsorption capacity and safety, non-toxic and harmless. In this study, high-performance Cr(VI) adsorption material (F-MgO) was prepared by combination hydrothermal modification of recycling MgO and doping of solid waste fly ash with the MgO that was a by-product of high magnesium laterite nickel ore. The adsorption properties of F MgO composites for Cr(VI) were evaluated, and the maximum adsorption capacity of Cr(VI) by F MgO reaches 172.6 mg/g at pH = 2.0. The F-MgO also showed high stability and excellent cycle adsorption performance. The adsorption mechanism was extensively studied by adsorption kinetics and DFT theoretical calculation, and electrostatic adsorption and chemical interaction between Cr(VI) and F MgO active sites were demonstrated. The prepared F MgO composites from waste resources with a simple synthetic method have great potential in the treatment of chrome-containing wastewater to achieve the purpose of treating waste with waste.
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ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
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2024
·
IF 0
Hammad Eman N.,Eltaweil Abdelazeem S.,Abouelenein Saeyda A.,El-Subruiti Gehan
Water contamination by heavy metals, especially chromium (VI), poses a critical environmental issue due to its carcinogenic nature and persistence in the environment. Addressing this, the current study develops an efficient adsorbent, CPBr-MIL-88A@AmGO, which utilizes the synergistic capabilities of Cetylpyridinium bromide–modified MIL-88A and amine-functionalized graphene oxide to enhance Cr(VI) removal from aqueous solutions. The obtained results indicate that CPBr-MIL-88A@AmGO achieves its highest removal efficacy at pH 2, where the interaction of CPBr and AmGO’s positively charged centers significantly contributes to the adsorption processes. According to the Langmuir isotherm model, the composite’s adsorption capacity reached a maximum of 306.75 mg/g. The adsorption kinetics adhered to a pseudo-second-order model along with the endothermic nature of the process. Although the presence of SO 4 2- ions significantly reduces adsorption capacity, other interfering ions including Na + , K + , Ca 2+ , Cl - , and NO 3 - only slightly affect it. Remarkably, the composite maintains high removal efficiency, over 82%, even after 7 recycling tests, underscoring its potential for practical applications in water treatment systems. The proposed mechanism involves the contribution of electrostatic attractions, ion exchange, complexation, and the reduction of Cr(VI) to Cr(III) in the removal process. This study not only offers a potent solution for Cr(VI) remediation but also contributes to sustainable water resource management.
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Journal of Water Process Engineering
·
2024
·
IF 6.3
Shuang Fu,Yingbo Chen,Xintong Wu,Liu Ye,Linzhe Xu,Xinyu Zhao
Nanofiltration (NF) membranes play a crucial role in wastewater treatment based on their unique separation mechanism. However, conventional polyamide nanofiltration membranes are susceptible to degradation in extreme pH or chlorine environments, resulting in a limited range of applications. In this study, hydrophilic functional coatings were constructed on polyethersulfone (PES) support using the biopolymer materials, κ-carrageenan (κ-CGN) and sodium carboxymethyl cellulose (CMC). The coatings were cross-linked with glutaraldehyde (GA) to form a dense three-dimensional network structure insoluble in water, enabling structural stability in harsh environments. The Na 2 SO 4 retention of the κ-CGN/CMC/PES composite membranes was maintained at 92.1 and 91.4 % after 38 days of immersion in 20 wt% H 2 SO 4 and 2 M NaOH aqueous solutions, respectively. Meanwhile, κ-CGN/CMC/PES maintained a good salt retention (Na 2 SO 4 , ∼90.0 %) after chlorine treatment (72,000 ppm h). The excellent separation performance of the κ-CGN/CMC/PES composite membranes at different pH and concentration of Cr (VI) indicated its wide application for Cr(VI) removal at harsh conditions.
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