SEPARATION AND PURIFICATION TECHNOLOGY
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2022
·
IF 9.136
Tingting Wang,Yongchang Sun,Lu Bai,Caohui Han,Xiaoyin Sun
Chitosan coated biochar-supported nano zero-valent iron aerogel (C-nZVI@BC) was successfully synthesized for the efficient removal of Cr(VI) from aqueous solution. Results showed that the C-nZVI@BC has a 2.1-fold higher adsorption capacity of Cr(VI) than the uncoated sample. Chitosan coating on nZVI@BC and BC support could prevent the oxidation and agglomeration of nZVI. Ultrafast adsorption of Cr(VI) with 61 %, 77 %, and 87 % of the maximum adsorption capacities were achieved within 1 min with the initial concentrations of Cr(VI) at 100 mg/L, 300 mg/L, and 600 mg/L, respectively. The C-nZVI@BC exhibited high adsorption performance under aerobic conditions, and showed high Cr(VI) removal rates (>83 %) in a wide pH range (2–8). Cr(VI) and Cr(III) could be simultaneously removed by C-nZVI@BC, and the key mechanisms were adsorption, reduction, and complexation. The acid and alkali resistance experiment of C-nZVI@BC showed that C-nZVI@BC still has better adsorption capacity of Cr(VI) (96.7 mg/g) in acid environment. The application of C-nZVI@BC in the simulated electroplating wastewater treatment indicated a high removal rate of Cr(VI). C-nZVI@BC could effectively reduce the low concentration of Cr(VI) below the standard of the World Health Organization. The syringe filtration and column adsorption experiments implied the potential of C-nZVI@BC for Cr(VI) removal in groundwater. In addition, C-nZVI@BC could be a direct reducing agent for Cr(VI) and an activator of persulfate (PS) for the degradation of antibiotics, and C-nZVI@BC + PS showed 77 % and 82 % removal of tetracycline and chlortetracycline within 5 min. Overall, C-nZVI@BC was a suitable adsorbent for pollutant removal.
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高影响因子
APPLIED SURFACE SCIENCE
·
2022
·
IF 7.392
Jian Ma,Congjie Liang,Changjiang Yu,Huaming Li,Hui Xu,Yingjie Hua,Chongtai Wang
Photocatalytic reduction of hexavalent chromium (Cr(VI)) is an effective way to reduce its environmental risk. However, it remains a challenge to achieve a high removal rate in mild conditions. In order to efficiently remove Cr(VI) from water, a novel Z-scheme heterojunction composite photocatalyst rCB-20 (Cu 2 O/rGO/BiOBr, 20% Cu 2 O) was successfully prepared using a simple two-step strategy in this work. The characterizations of the catalyst show that the Z-scheme heterojunction formed between Cu 2 O and BiOBr is favorable for facilitating the separation of photogenerated carriers. The existence of rGO can reduce the resistance of electron transport. Therefore, the composite photocatalyst exhibits a very high photocatalytic activity in the photoreduction of Cr(VI). For example, using it to completely remove Cr(VI) with a concentration of 20 mg•L −1 in the pH = 4 solution only requires 40 min. Even the complete removal of the same concentration of Cr(VI) in neutral water at pH 7 does not take more than 90 min. Meanwhile, it possesses a high stability in catalytic activity and structure.
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高影响因子
ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2022
·Vol. 414
·期 24
·7253-7263
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IF 4.478
Mei Xiping,Wang Dongxiu,Wang Songbai,Li Junfen,Dong Chuan
In this paper, intrinsic dual-emission fluorescent carbon dots (CDs) doped with N and S atoms have been firstly fabricated. The characterization results show that CDs are successfully synthesized with two separate fluorescence emissions at 468 nm and 628 nm, respectively. The strong and selective interaction of Cr (VI) ions with CDs lead to obvious fluorescence decrease of CDs at 468 nm, which is caused by a mixed quenching mechanism. At the same time, the fluorescence at 628 nm increase. Interestingly, the CDs solution show obvious color change under the daylight and UV light, so visualization detection of Cr (VI) can be realized in water samples. Based on the data of the emission intensity ratios of F 468 / F 628 , Cr (VI) can be detected from 3.8 to 38.9 μM combined with the linear correlation coefficient of 0.998, and the lowest detection concentration is 47.2 nM. The platform is satisfactorily applied to the detection of Cr (VI) ions in water samples. In addition, the CDs could be applied as fluorescent probes for cell imaging with dual fluorescent emission. Graphical abstract
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PubMed
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2022
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IF 5.876
Hao Wang,Shuai Wang,Shixing Wang,Libo Zhang,Yang Zhou,Fan Yang
In the past decades, due to the worst effect of hexavalent chromium on human and environmental health, people have been committed to removing hexavalent chromium from industrial wastewater. In recent years, metal organic frameworks (MOFs) adsorbents have attracted more and more attention in the removal of pollutants from water. Here, an efficient and selective adsorbent(UiO-66-PRAA) was prepared by modified UiO-66-NH 2 with phenothiazine-N-rhodanine to remove Cr(VI) ion from wastewater. The maximum absorption capacity of UiO-66-PRAA at 303 K and pH = 2 was 333.67 mg/g for Cr(VI). Which is higher than that of bare UiO-66-NH 2 . Elovich kinetic and Sips isotherm models are more suitable for describing the adsorption process of Cr(VI) on UiO-66-PRAA, which indicates that the process is a chemically controlled multilayer adsorption. In addition, the removal mechanisms include chelation, ion exchange and reduction. The adsorbent still shows good adsorption performance under the coexistence of different ions. The excellent cycle performance of UiO-66-PRAA confirms its high potential in removing Cr(VI) from polluted water. In general, UiO-66-PRAA has been shown well adsorption properties and reusability, and our finding might provide a new idea for developing efficient and reusable adsorbent to remove Cr(VI) from wastewater.
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高影响因子
ENVIRONMENTAL POLLUTION
·
2023
·
IF 8.9
Changjin Liang,Honghai Wu,Yufeng Guan
Ferrihydrite (Fh) is a vital geosorbent in the natural environment. Here, Fh materials with lanthanum (La) substituted in varied La/La + Fe ratios were synthesized, and these La-Fh materials were investigated in-depth via adsorption kinetic and isothermal experiments to explore their adsorption performance for chromate [Cr(VI)] in soils. Material properties of La-Fh were further characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectrometer (FTIR), and X-ray photoelectron spectroscopy (XPS). The results clearly indicate that La 3+ can be integrated into the Fh lattice, but the increase in La amount substituted into Fh is slowed down when the La/La + Fe ratio reaches to a larger value. Those La 3+ cations that fail to become integrated may either get adsorbed or form a phase of La(OH) 3 on La-Fh surfaces. We also find that La substitution reduces the specific surface area (SSA) of La-Fh samples but raises their pH pzc , which hampers La-Fh conversion to hematite and thus increases the chemical stability. These changes are related to the La-Fh structure and surface aspects, but they do not negatively affect the Cr(VI) adsorption efficacy, which can be promoted over a wide pH range to an alkaline pH. For instance, the maximum adsorption amount of Cr(VI) by 20%La-Fh is 30.2 mg/g at a near-neutral pH. However, the entire chromate adsorption processes are affected by H 2 PO 4 − and humic acid due to their strong affinities for Cr(VI), but almost not influenced by NO 3 − and Cl − . All the Cr(VI)-Fh reactions are well described by the fitted adsorption Freundlich model and conform to the pseudo-second-order reaction kinetic equation . The mechanisms which enhance La-Fh's adsorption ability for Cr(VI) are governed by chemical interactions, because La substitution can increase the hydroxyl density on Fh surfaces and thus improve the reactivity of La-Fh towards Cr(VI), leading to an evidently enhanced Cr(VI) immobilization onto La-Fh.
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PubMed
高影响因子
SYNTHETIC METALS
·
2021
·
IF 3.266
Yaoyao Hao,Yinyue Zhou,Nuohan Xu,Kaixun Tian,Pei Liang,He Jiang
Iron oxide @ poly(m-phenylenediamine) (Z) particles (Fe 3 O 4 @PmPD(Z)) were synthesized by in-situ polymerization of PmPD on the Fe 3 O 4 nanoparticles via ZIF-8 intermediate platform to remove Cr(VI) from wastewater. Analyses of FT-IR, TEM, etc. were performed to evaluate the morphology and structure of synthesized material, and the results confirmed the successful synthesis of Fe 3 O 4 @PmPD(Z). In addition, the TEM and BET analyses results show that the PmPD shell is a flocculating structure, and the increased specific surface area increases the contact with Cr(VI). The Fe 3 O 4 @PmPD(Z) exhibits much better Cr(VI) adsorption performance than Fe 3 O 4 @PmPD, and its adsorption capacity is increased by about 30%, the maximum Cr(VI) adsorption capacity can reach 371.75 mg g −1 at 318 K. According to FT-IR, XPS , and EDS , the removal mechanisms can be attributed to the redox reaction of Cr(Ⅵ) and NH to form N and Cr(Ⅲ), and N shares electron pair with Cr(Ⅲ) to form chelation. At the same time, the appearance of N + also contributes to the removal of Cr(Ⅵ) by generating electrostatic attraction with the negatively charged HCrO 4 - . Besides, the Fe 3 O 4 @PmPD(Z) also exhibits excellent properties of recovery and reuse. Therefore, the current work proves that Fe 3 O 4 @PmPD(Z) has the potential to remove heavy metals in wastewater.
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高影响因子
Journal of Water Process Engineering
·
2023
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IF 7
Feng Li,Zhen Wu,Xiaolong Tang,Xiangwei Li,Xingqiang Liu,Shuyuan Yu,Longfu Wei,Changlin Yu
Ti-based semiconductors the eco-friendly materials. Here, using n-tetrabutyl titanate and calcium acetate as raw materials, a dual- Z -scheme TiO 2 /CaTi 4 O 9 /CaTiO 3 heterojunction was facilely constructed via the solvothermal combination with calcination route. The obtained samples were intensively characterized by some physicochemical methods such as TG, XRD, FT-IR, SEM , TEM, XPS, UV–Vis DRS, PL , N 2 physisorption-desorption, and electrochemical tests. The optimum TiO 2 /CaTi 4 O 9 /CaTiO 3 photocatalyst fabricated at a solvothermal temperature of 160 °C and calcination temperature of 700 °C shows high efficiency for H 2 production, which was 11, 5, and 1.6 times higher than that of rutile-phase TiO 2 , CaTiO 3 and commercial P25(TiO 2 ), respectively. The Cr(VI) reduction rate over TiO 2 /CaTi 4 O 9 /CaTiO 3 was 3.3, 5.2, and 3.1 times higher than those of rutile-phase TiO 2 , CaTiO 3, and commercial P25, respectively. The superior photocatalytic performance is attributed to the strong redox ability of carriers excited by wide band gap semiconductors and the unique dual- Z -scheme which largely promotes carrier separation.
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高影响因子
Journal of Water Process Engineering
·
2023
·
IF 7
Chumin Yan,Xiaoli Dong,Yu Wang,Nan Zheng,Hongchao Ma,Xiufang Zhang
Inorganic semiconductors prepared from MOFs as sacrificial precursors are promising photocatalytic materials. In this work, the direct Z -scheme MoS 2 /NH 2 -MIL-68(In)-derived In 2 S 3 (MoS 2 /In 2 S 3 ) heterojunction composites have been synthesized by sulfidation treatment of MoS 2 /NH 2 -MIL-68(In) (MoS 2 /NM68) composites. Morphological and crystal structural results confirmed that MoS 2 was uniformly dispersed in In 2 S 3 . According to the reduction for Cr(VI) experimental results, the photocatalytic performance of MoS 2 /In 2 S 3 heterojunction composite under visible light irradiation is significantly better than that of pristine MoS 2 and In 2 S 3 , respectively. In addition, the photocatalytic activities of the MoS 2 /In 2 S 3 (II) at different pH and high concentrations of Cr(VI) were also investigated. This paper presents a novel approach to the construction of heterojunction photocatalytic materials using MOFs as sacrificial precursors.
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高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Cong Liu,Yanhui Li,Xu Cui,Chen Liang,Gaojun Xing,Qian Duan
This study synthesized a recyclable dual-responsive core–shell photocatalyst Fe 3 O 4 @SiO 2 @TiO 2 @ZnIn 2 S 4 /ZnPc (FSTZP) used for hexavalent chromium (Cr (VI)) reduction. Core-shell Fe 3 O 4 @SiO 2 @TiO 2 (FST) was prepared and modified with ZnIn 2 S 4 and zinc-tetra ( N -carbonylacrylic) aminephthalocyanine (ZnPc) to obtain FSTZP and characterized by XRD, XPS, SEM, HRTEM and UV–vis DRS. In FSTZP, ZnIn 2 S 4 could provide more adsorption active sites and promote charge-carrier separation; ZnPc would efficiently use visible light to transfer energy. Both of ZnIn 2 S 4 and ZnPc in FSTZP could improve the light-harvesting resulting in excellent photocatalytic performance of FSTZP towards Cr (VI) reduction and pollutant degradation. The highest reduction efficiency of Cr (VI) by FSTZP (0.3 g/L) was up to 96.4% in 60 min at pH = 6. The removal efficiencies of Rhodamine B (RhB), Methylene blue (MB), Methyl Orange (MO) and Tetracycline hydrochloride (TC•HCl) by FSTZP (0.3 g/L) under visible light were 99%, 99%, 95% and 86% in 40 min at pH = 6. Meanwhile, almost all of Cr (VI) and organic molecules in the coexistence system could be removed by FSTZP under visible light. FSTZP also presented the adsorption property and the mechanism of dual-responsive FSTZP for Cr (VI) reduction and organic pollutants removal was explored. Moreover, as an efficient photocatalyst, FSTZP still maintained stability after reused for fourth photocatalytic cycle by magnetic recovery. This study was devoted to develop an efficient photocatalyst suitable for removing Cr (VI) and organic pollutants.
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高影响因子
ChemCatChem
·
2021
·Vol. 13
·期 8
·2034-2044
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IF 5.686
Lei Guo,Jingxia Yang,Huiqing Zhang,Runkai Wang,Jingli Xu,Jinjie Wang
Graphical The rule of seven : The brilliant photocatalytic performance of CN−OH/CeO 2 −NP is due to the synergistic improvement of surface structure. The heptazine ring of g−C 3 N 4 can establish a consummate complexing with K ion. Moreover, unsaturated-coordination O between CN−OH/CeO 2 −NP composite can establish a firmly interfacial interaction with g−C 3 N 4 nanosheets by p–π bond. Furthermore, the hydroxyl groups on the surface of ceria can form hydrogen bond with the NOH/NH x group of g−C 3 N 4 nanosheets. Photocatalysis is an efficient and eco-friendly method of solving the environmental problems, but the low charge separation efficiency of photocatalysts limits their application. Herein, we report the fabrication of CeO 2 /g−C 3 N 4 composites via an in-situ growth of CeO 2 on the dispersed g−C 3 N 4 sheets (CN−OH) in an strong KOH condition, and the resultant CeO 2 /CN−OH composites set up a new interface structure, which demonstrate a dramatically boosted the photocatalytic activity compared with CeO 2 /g−C 3 N 4 composites by conventional two-step combination method. The decomposition efficiency of CeO 2 /CN−OH for 2,4-dichlorophenol (2,4-DCP) degradation comes up to 6 times of bare CeO 2 or g−C 3 N 4 . Compared to conventional CeO 2 /g−C 3 N 4 , the CeO 2 /CN−OH showed 65.9 % and 23.2 % improvement for 2,4-DCP and Cr(VI) removal, respectively. The significantly enhanced photodegradation ascribe to the alkaline modified CN−OH and the fabrication of CeO 2 /CN−OH n–n type heterojunction, both can improve the charge separation efficiency and increase the reaction active sites. Furthermore, the probable pathway and concreted photocatalytic mechanism for 2,4-DCP degradation are proposed based on the detected intermediate products.
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高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2020
·
IF 5.774
Zhoujun He,Ruowen Liang,Chen Zhou,Guiyang Yan,Ling Wu
Industrial sewage often contain metal ions and dyes, and it is difficult to efficiently remove them simultaneously. In this work, novel ternary MIL-53(Fe)/carbon quantum dots/noble metal (MIL-53(Fe)/CQDs/MNPs, MNPs = Ag, Pd, Au) nanocomposites have been rationally constructed and successfully fabricated by a facile two-step strategy with self-assembling and in-situ photoreduction. The resulting MIL-53(Fe)/CQDs/2%Au composite exhibits excellent photoactivity for the Cr(VI) reduction, the reduction ratio is nearly 100% after 20 min of visible light illumination. The rate constant of MIL-53(Fe)/CQDs/2%Au is calculated to be 0.1820 min −1 , which is around 7.4, 2.76, 1.77 and 1.47 times higher than that of as-prepared MIL-53(Fe), MIL-53(Fe)/CQDs, MIL-53(Fe)/CQDs/2%Ag and MIL-53(Fe)/CQDs/2%Pd, respectively. More significantly, MIL-53(Fe)/CQDs/2%Au nanocomposite has been proven to serve as bifunctional photocatalyst for simultaneously removing Cr(VI)/dye mixed system pollutants. The superior photoactivity may be due to the enhanced light absorption intensity, the superior electrical conductivity of Au and CQDs, as well as surface plasmon resonance (SPR) effect of Au. In particular, the possible photocatalytic reaction mechanism has been carefully investigated and proposed.
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高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2020
·Vol. 55
·期 30
·14953-14964
·
IF 3.553
Lv Bo,Xia Lihong,Yang Yu,Wang Xiaoming,Yin Chen,Li Yaoping,Zhang Fuqin
Carbon fibers (CFs) and TiH 2 were used as raw materials to grow TiC on the surface of CFs in a molten salt system. After hydrothermal reaction with sodium hydroxide, part of TiC was converted into sodium titanate. The sodium ions were substituted by H + by the hydrochloric acid solution treatment. CFs@TiC/TiO 2 composite was generated after high-temperature treatment. XRD, Raman, XPS, SEM, and AFM were used to characterize the structure and morphology of the composites. Results showed that a porous TiC film layer was homogeneously formed which was evenly wrapped on the surface of CFs. Through hydrothermal, displacement, and calcination processes, part of TiC was transformed into anatase TiO 2 with controllable morphology. Photocatalytic degradation experiments by the composite catalysts were carried out. The chemical reactions involved in the formation of composite structures and their effects on photocatalysis were analyzed and discussed. Notably, the morphology characteristics of the heterogeneous structure has a marked impact on the photocatalytic degradation of organic pollutants and photocatalytic reduction of hexavalent chromium [Cr(VI)]. Furthermore, the composites can be easily recycled and reused with good reactivity.
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高影响因子
危险品化学品经营许可证（带存储）