JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY
·
2020
·Vol. 20
·期 3
·1660-1669
·
IF 1.134
Deng Yu-Ying,Xiao Xin-Feng,Wang Dan,Han Bo,Gao Yu,Xue Jian-Liang
Cu-BTC was synthesised by hydrothermal method in this study to adsorb and remove the toxic heavy metal hexavalent chromium Cr(VI) in water. The EDTA-chitosan/Cu-BTC was prepared by the surface modification of Cu-BTC with EDTA-modified chitosan. The initial concentration effects of adsorbed
chromium solution, adsorbent dosage, adsorption time, adsorption temperature and pH of chromium solution on adsorption capacity were estimated using the single-factor optimisation experiment. Results show that the adsorption capacity of the modified composite was higher than that of Cu-BTC.
Cu-BTC and EDTA-chitosan/Cu-BTC exhibited significant adsorption of Cr(VI) under acidic conditions in water and basically independent of temperature. Their adsorption processes conformed with the pseudo-second-order model. The Langmuir adsorption isotherm model obtained the adsorption isotherm,
which indicated that the adsorption process was single molecule adsorption. Isotherm fitting obtained the maximum adsorption amounts of Cr(VI) for Cu-BTC and EDTA-chitosan/Cu-BTC at 27.32 and 46.51 mg·g-1, respectively. Factor and principal component analyses show that the
main factors affecting the adsorption of Cr(VI) in the EDTA-chitosan/Cu-BTC composites are pH, initial concentration and adsorption time. Therefore, EDTA-chitosan-modified Cu-BTC was a more feasible metal-organic framework material than Cu-BTC because of better adsorption performance, which
can be used for adsorption removal of Cr(VI) in water.
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SCIENCE OF THE TOTAL ENVIRONMENT
·
2022
·
IF 10.753
Jing Yang,Qian Guo,Lei Li,Ruixue Wang,Yucheng Chen,Xingrun Wang
Compare to the content of Cr(VI), the distribution of specific Cr(VI) species in soil is rarely paid attention to, which may lead to an inaccurate environmental risk assessment of Cr(VI) contaminated soil or inability to meet stringent requirement for soil remediation . Herein, to reveal the primary mechanisms and factors controlling the evolution of Cr(VI) species in soil, the distribution of Cr(VI) and Cr(III) species in soils with different particle sizes and textures was systematically investigated by using a modified sequential extraction procedure and spectroscopy characterizations (e.g., SEM-EDS mapping). The results show that a significant proportion of Cr(VI) can be captured by minerals containing exchangeable calcium ions and metal oxide hydrates in the soil, forming a relatively stable adsorbed Cr(VI). Also, a small fraction of Cr(VI) can precipitate as calcium chromate with free calcium ion which is the most stable Cr(VI) species in the soil. The majority of Cr(VI) discharged into soil tends to be reduced by ferrous ions or minerals containing ferrous ions with a product of Fe(III)-Cr(III) coprecipitate. Therefore, the speciation of Cr in the soil is closely correlated to Fe and Ca. After the equilibrium of adsorption, precipitation, and reduction reactions of Cr(VI), the rest of Cr(VI) retains as the form of its original water-soluble state in soil. The evolution of Cr(VI) species and the content of specific Cr species in soil are mainly determined by the contents of iron, exchangeable calcium ions and metal oxide hydrates, which effect the Cr(VI) reduction, precipitation and adsorption, respectively.
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高影响因子
KOREAN JOURNAL OF CHEMICAL ENGINEERING
·
2022
·Vol. 39
·期 7
·1839-1849
·
IF 3.146
Zhang Xiaoting,Zhang Shusheng,Ouyang Gangfeng,Han Runping
A zirconium-based metal organic framework (UiO-66-NH 2 ) was prepared using a greener approach for the removal of hexavalent chromium (Cr(VI)) from solution. The characterization of UiO-66-NH 2 was performed using several methods, and the influence of the solution pH, adsorbent dosage, salt, adsorption time, Cr(VI) concentration and adsorption temperature on adsorption quantity was performed in batch mode. UiO-66-NH 2 can efficiently remove Cr(VI) through the synergistic effect of adsorption and reduction. At pH solution of 1.1 and solid-to-liquid ratio of 2 g·L −1 , the removal rate of 100 mg·L −1 Cr(VI) increased to 95.2%. The maximum adsorption capacity of UiO-66-NH 2 from Langmuir model was 252 mg·g −1 . The adsorption equilibrium process can be well described by Langmuir, Koble-Corrigan and Temkin models, while the kinetic process can be predicted by pseudo-second-order and Elovich model. UiO-66-NH 2 showed a good adsorption capacity in a wide range of pH (pH=1.1–10) and also had better regeneration performance after five cycles using 0.01 mol·L −1 NaOH; consequently, it can be a promising adsorbent for the removal of Cr(VI) from solution.
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Nanomaterials
·
2022
·Vol. 12
·期 21
·3923
·
IF 5.719
Wen-Yi Wang,Tian Sang,Yan Zhong,Chao-Hao Hu,Dian-Hui Wang,Jun-Chen Ye,Ni-Ni Wei,Hao Liu
The surfactant modification of catalyst morphology is considered as an effective method to improve photocatalytic performance. In this work, the visible-light-driven composite photocatalyst was obtained by growing CdS nanoparticles in the cubic crystal structure of CdCO3, which, after surfactant modification, led to the formation of CdCO3elliptical spheres. This reasonable composite-structure-modification design effectively increased the specific surface area, fully exposing the catalytic-activity check point. Cd2+from CdCO3can enter the CdS crystal structure to generate lattice distortion and form hole traps, which productively promoted the separation and transfer of CdS photogenerated electron-hole pairs. The prepared 5-CdS/CdCO3@SDS exhibited excellent Cr(VI) photocatalytic activity with a reduction efficiency of 86.9% within 30 min, and the reduction rate was 0.0675 min−1, which was 15.57 and 14.46 times that of CdS and CdCO3, respectively. Finally, the main active substances during the reduction process, the photogenerated charge transfer pathways related to heterojunctions and the catalytic mechanism were proposed and analyzed.Keywords:surfactant;CdS/CdCO3;photocatalytic;Cr(VI)
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SCIENCE OF THE TOTAL ENVIRONMENT
·
2018
·
IF 4.61
Shunquan Shi,Jiakuan Yang,Sha Liang,Mingyang Li,Quan Gan,Keke Xiao,Jingping Hu
Fe 3 O 4 @SiO 2 -NH 2 magnetic particles with core-shell structure were attached on carboxylated biochar derived from phoenix tree leaves to synthesize a novel magnetic biochar for removing Cr(VI) ions from acidic solutions. FSEM, FTEM, XRD characterizations of the synthesized magnetic biochar revealed that the Fe 3 O 4 @SiO 2 -NH 2 magnetic particles distributed uniformly on the surface or macrospores of carboxylated biochar by strong chemical bonding. The Cr(VI) ions adsorption capacity of magnetic biochar was 27.2 mg·g −1 , surpassing original carboxylated biochar (18.2 mg·g −1 ). VSM and XPS characterizations demonstrated that the attached Fe 3 O 4 @SiO 2 -NH 2 magnetic particles not only endowed biochar with perfect magnetic property (23 emu·g −1 ) but also provided complexing sites for binding Cr(III) cations reduced from Cr(VI) anions. The Cr(VI) ions removal by magnetic biochar contained three steps: (1) adsorption of Cr(VI) anions by protonated functional groups; (2) reduction of Cr(VI) anions to Cr(III) cations by electron-donor groups; and (3) chelation of Cr(III) cations by amine groups. The adsorption recycling test showed that magnetic biochar kept 85% of its initial Cr(VI) adsorption capacity at the sixth cycle, and the Fe leakage under pH 1.0 was smaller than 0.25 mg·L −1 . The results indicated that this novel magnetic biochar was applicable for the practical treatment of Cr(VI)-containing wastewater.
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JOURNAL OF HAZARDOUS MATERIALS
·
2019
·
IF 7.65
Li Song,Yuefeng Feng,Changqing Zhu,Fuqiang Liu,Aimin Li
Cr(VI) and Cd(II) are typical heavy metal ions and their co-removal is significant. Nitrogen-doped, bi-functional, and biomass-based composites (CP-BA) were successfully applied for efficient and synergistic removal of Cr(VI) and Cd(II). The mutual promotion ratios of adsorption capacity by Cr(VI) and Cd(II) were 161.32 % and 14.13 %, respectively. In addition, all coexisting inorganic anions could extremely promote the removal of Cd(II) with the best promotion ratio upon phosphate ions as high as 80.00 %. The following co-removal mechanisms were deeply revealed: (1) Cr(VI) combined with protonated imine groups could weaken the electrostatic repulsion between CP-BA and Cd(II) by electrostatic shielding, and further promoted the coordination of Cd(II) with hydroxyl, carboxyl and neutral imine groups. (2) Cd(II) which were coordinated to neutral imine groups could form cation bridges, and thus promoted the interaction with Cr(VI) because of the electrostatic attraction. Moreover, the removal capacity for Cr(VI) and Cd(II) did not display obvious reduction even after four cycles. Therefore, CP-BA showed a great potential in the co-removal of inorganic anion-cation complexes from wastewater.
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JOURNAL OF APPLIED POLYMER SCIENCE
·
2018
·Vol. 135
·期 30
·46530
·
IF 1.901
Kaijie Dong,Qinze Liu,Gang Wei,Tao Hu,Jinshui Yao,Xian Zhang,Tingting Gao
A novel magnetic adsorbent, poly(catechol-1,4-butanediamine)-coated Fe 3 O 4 composite (Fe 3 O 4 @PCBA), was successfully fabricated via an easy and gentle method according to the mussel-inspired adhesion property of polydopamine. Effects of many factors on the adsorption performance of Fe 3 O 4 @PCBA for Cr(VI) were investigated, including temperature, pH value, contacting time, adsorbent dosage, and initial Cr(VI) concentration. The thermodynamics, adsorption isotherm, kinetics, and intraparticle diffusion of adsorption were also studied systematically. Results indicated that the removal rate of Cr(VI) was approximately close to 100% when the initial concentration was less than 120 mg/L, and the maximum uptake capacity of Fe 3 O 4 @PCBA for Cr(VI) was 280.11 mg/g complied with Langmuir isotherm model. Accordingly, the nocuous Cr(VI) could be partially reduced to Cr(III) during the adsorption period. Hopefully, this strategy could be extended to prepare series of magnetic Fe 3 O 4 @catechol–amine adsorbents with different amino and phenolic hydroxyl groups for Cr(VI) removal. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135 , 46530.
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ACS Applied Nano Materials
·
2024
·
IF 5.3
Xingrui Tong,Jinling Bao,Danfeng Chang,Dapeng Wang,Haibo Chang,Liquan Jing
Designing an efficient hole–electron separation method is essential to improving the photocatalytic efficiency of photocatalysts. Herein, we constructed a 3D MoS2/MgIn2S4 S-scheme heterojunction material using a solvothermal method. The built-in electric field formed by the interaction between MoS2 and MgIn2S4 promoted the separation of electrons and holes, significantly improving the photocatalytic activity of 3D MoS2/MgIn2S4. The 3% MoS2/MgIn2S4 composite photocatalyst successfully achieved a 100% reduction of Cr(VI) within 90 min and demonstrated good hydrogen production efficiency without using a sacrificial agent. Theoretical calculations confirmed the formation of S-scheme heterojunctions. Malondialdehyde and dehydrogenase tests showed that the Cr(VI) solution after reduction was not harmful to plant growth. Furthermore, we systematically investigated the effects of different Cr(VI) concentrations, catalyst dosages, ions, pH values, and organic acids on photocatalytic efficiency. The design of the S-scheme heterojunction photocatalysts provided a promising strategy for the photoreduction 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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ENVIRONMENTAL POLLUTION
·
2020
·
IF 6.793
Chuanqi Tang,Yiming Zhang,Jiangang Han,Ziqi Tian,Liang Chen,Jianqiang Chen
Supported carbon quantum dots (CQDs), used as fluorescent sensors for the detection of metal ions , have rarely been used to remove heavy metals from water. Nitrogen-doped CQDs immobilized in hydrophilic silica hydrogels exhibited a more superior sensitivity and selectivity for the detection of Re(VII) and Cr(VI) than other metal ions, including Fe(III), Fe(II), Zn(II), Cu(II) and Mn(II). For the first time, low limits of detection (LOD) of 2.3 μM for Re(VII) detection and 65 nM for Cr(VI) detection were reported by a facile method. Based on the high selectivity of fluorescent silica hydrogels for Re(VII) and Cr(VI) detection, the removal of Re(VII) and Cr(VI) by graphene oxide (GO) in water was monitored with the hydrogels used as a turn-off fluorescent sensing platform. The consistent results of the sorption isotherms of each metal on GO, which were obtained from the fluorescence spectra and by UV absorption, further verified the possibility of monitoring metal removal by fluorescence detection. Remarkably, GO removed 1186 mg/g of Re(VII) but only 178 mg/g of Cr(VI). The density functional theory (DFT) calculations indicated that both Re(VII) and Cr(VI) formed stable bonds with silica hydrogels, confirming that the interactions between the metal ions and the substrate would promote the fluorescence quenching of the supported CQDs. On the other hand, Re(VII) interacted more strongly with the carboxyl groups of GO than Cr(VI). In addition, a real-time detection system was designed to alarm the service life of a GO filter used for Re(VII) removal.
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CHEMICAL ENGINEERING JOURNAL
·
2020
·
IF 10.652
Yue Hu,Guangming Zhan,Xing Peng,Xiufan Liu,Zhihui Ai,Falong Jia,Shiyu Cao,Fengjiao Quan,Wenjuan Shen,Lizhi Zhang
In this study, we coated a high proton conductive shell on the zero-valent iron (ZVI) surface by mechanically ball-milling ZVI with oxalic acid dihydrate (OX-ZVI), and demonstrated that the generated FeC 2 O 4 ·2H 2 O shell dramatically improved the Cr(VI) removal rate of ZVI by about 15–80 times. Owing to a higher proton conductivity of FeC 2 O 4 ·2H 2 O shell than that of Fe 2 O 3 shell, proton could easily transfer through FeC 2 O 4 ·2H 2 O shell into iron core and be reduced to H, accompanying with fast surface-bound Fe 2+ generation, resulting in high efficiency of Cr(VI) removal in a wide pH range. Meanwhile, the removed Cr(VI) was deposited on OX-ZVI surface in the formation of Fe x Cr 1-x (OH) 3 composites, accompanied by the appearance of typical hollow structure derived from iron core dissolution. This study clarifies the significance of proton transfer on the reactivity of zero-valent iron, and also provides a new strategy to prepare highly active zero-valent iron for Cr(VI) removal.
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CHEMICAL PHYSICS LETTERS
·
2025
·
IF 3.1
Hainan Zhang,Shuhui Liang,Jianwei Zhang,Xiangge Han,Weiqi Zhou,Jia Gao,Yaohua Li,Shuliang Dou,Yao Li,Feifei Ren
Vanadium dioxide (VO₂) undergoes reversible metal–insulator transitions at critical temperature of 68 °C, rendering it promising for tunable electromagnetic applications. Here, Cr-doped VO₂/Ethyl cellulose (EC) composites are synthesized to raise the transition temperature to 87 °C while retaining shielding effectiveness values of 9.9–26.3 dB (X-band) and 10.2–25.2 dB (Ku-band). Notably, the surface temperature of material plateaus at 70 °C after exposure to one sun for 10 min, preventing passive phase transitions under light exposure. This work provides valuable insights into the design of intelligent electromagnetic interference shielding materials with active thermal regulation capabilities.
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