Journal of Environmental Chemical Engineering
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2023
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IF 7.7
Qing Li,Xiaojie Zhuang,Guanhong Zhou,Zhenfei Yang,Ting Yang,Hongbo Xiao,Tao Xu,Wenlei Wang
A novel polyacrylic acid/carboxylated nanocellulose fiber/polyethylene glycol hydrogel loaded with nano-ZnO (ZnO-PAA/CNF/PEG: GH-2 (wt(ZnO)% = 12% and wt(PEG)% = 16%)) was synthesized to remove Cr(VI) from wastewater by adsorption synergistic photocatalytic reduction. The effects of ZnO content, PEG content and pH on the removal efficiency of Cr(VI) were investigated. The removal performance and mechanism of Cr(VI) by hydrogels were systematically studied by various techniques. The results showed that when the initial pH = 2, the initial concentration of Cr(VI) = 20 mg/L, the hydrogel dose = 0.5 g/L, and Irradiation power of mercury lamp was 500 W, the removal efficiency of Cr(VI) was 97.22% (dark adsorption for 60 min and photocatalysis for 50 min). The addition of PEG greatly reduced the agglomeration of nano-ZnO in GH-2 and facilitated the separation of photogenerated electron-hole pairs. The adsorption process of Cr(VI) by GH-2 accords with pseudo-second-order kinetics. The photocatalytic process conforms to the pseudo-first-order reaction kinetics. Under the optimal experimental conditions, the removal efficiency of Cr(VI) by GH-2 was still as high as 87.99% after 5 cycles. The removal mechanism of Cr(VI) was mainly through electrostatic attraction, chemical adsorption and photocatalytic reduction. This study provides a feasible method for the synthesis of hydrogel materials with excellent adsorption synergistic photocatalytic performance for the treatment of Cr(VI)-containing wastewater.
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Journal of Environmental Chemical Engineering
·
2023
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IF 7.7
Wenjun Qu,Huili Wang,Guodong Li,Zhaoping Song,Xiaona Liu,Fengshan Zhang,Wenxia Liu,Dehai Yu,Dandan Ji
The removal of heavy metal ions and medical antibiotics from wastewater is crucial for environmental protection and human health. However, the adsorption capacities and reusability of previously reported adsorbent materials have been insufficient for efficient and sustainable wastewater treatment . In this study, we present a composite material, UiO-66-AMP@PAN, synthesized from metal-organic frameworks (MOFs) and polyacrylonitrile (PAN), which exhibits superior adsorption properties and reusability. The material demonstrates excellent adsorption capacities for heavy metal ions Pb(II) and Cr(VI) as well as the antibiotic tetracycline hydrochloride (TCH), among which the maximum adsorption capacities for Pb(II)(pH=7) and Cr(VI)(pH=5) and antibiotic tetracycline hydrochloride (TCH) (pH=9) were 455.8 mg/g, 442.08 mg/g and 405.92 mg/g, respectively. The adsorption efficiency of UiO-66-AMP@PAN as an adsorbent for adsorbing Pb(II)(pH=7) and Cr(VI)(pH=5) and the antibiotic tetracycline hydrochloride (TCH) (pH=9) remained above 90% even after ten consecutive cycles. The performance of UiO-66-AMP@PAN as an adsorbent has remained unchanged across multiple adsorption-desorption cycles, demonstrating its potential for long-term use in wastewater treatment applications. This innovative approach paves the way for the development of more efficient and environmentally friendly adsorption materials to address the challenges posed by heavy metal ions in wastewater and medical antibiotics.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2022
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IF 5.518
Junqi Wei,Yu Duan,Mingzhi Li,Haiying Lin,Jiatong Lv,Zixuan Chen,Jia Lin,Hainong Song,Ronghai Zhang,Lianghong Li,Lixin Huang
The nanoscale Zero-Valent Iron (nZVI) is vulnerable to being oxidized and aggregated, which weakens its reactivity and hampers application potential, manganese sulfide (MnS) modification and biochar supporter could provide a new possibility for this issue. In this work, the nZVI was firstly anchored onto bagasse biochar and then vulcanized by MnS (MnS-nZVI@BC) to achieve low aggregation and preeminent removal capacity. The flaky nZVI was uniformly in-situ growth on the biochar's surface to construct flower-like gullies, of which the surface was covered with some amorphous MnS layer. The monolayer chemical reaction dominated the Cr(VI) removal process, and higher temperature benefited the redox reaction to enhance the prominent removal capacity at 405.10 mg/g at 318.15 K, and it was slightly promoted with the coexisting ions. The quadruplicity of redox, electrostatic attraction, adsorption, and co-deposition should be taken into consideration in the mechanism, in which MnS could not only enhance the reducibility from dominant contributor nZVI, but also directly participate in the redox reaction; and Fe(II) also played an important role in the process; whereafter, Fe(III) and Cr(III) form Cr(III)/Fe(III) hydroxide deposited on the surface of the material. Overall, the findings exhibited the great potential of MnS-nZVI@BC in wastewater treatment while also providing an alternative basis to reveal mechanisms involving versatile aspects.
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SEPARATION AND PURIFICATION TECHNOLOGY
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2022
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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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APPLIED SURFACE SCIENCE
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2022
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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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ANALYTICAL AND BIOANALYTICAL CHEMISTRY
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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
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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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APPLIED SURFACE SCIENCE
·
2022
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IF 7.392
Yi Wen,Zheng Huang,Min Zhao,Longshan Zhao
The discharge of industrial heavy metal wastewater not only leads to environmental pollution, but also harms human health, so it is imperative to control heavy metal pollution. In the current work, a sequence of anatase/brookite TiO 2 @COF with different mass ratios, bi-phase TiO 2 and bare COF were successfully synthesized by simple hydrothermal synthesis. The photocatalytic activity of the prepared catalysts was assessed by reducing Cr(Ⅵ) in model pollutant (K 2 Cr 2 O 7 ). Under the condition of pH = 3, the Cr(Ⅵ) reduction rate of TiO 2 @COF-4 was as high as 99.19% in 30 min. The photocatalytic activity of TiO 2 @COF-4 remained stable in four consecutive cycles, suggesting that it has a potential application prospect for the removal of Cr(Ⅵ) in the actual environment. The morphology and structure of photocatalysts were observed by different techniques (SEM/EDS, HRTEM, BET analysis, XRD, FTIR and XPS). The specific reasons for the enhancement of photocatalytic performance of materials were explored by different methods (PL, UV–vis DRS, Mott-Schottky plots, I-T curves and EIS). Finally, we concluded that the photocatalytic system of TiO 2 @COF-4 may follow the typical direct Z- scheme mechanism. This work provides an effective solution for the water treatment of heavy metal pollution.
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ENVIRONMENTAL POLLUTION
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2023
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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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SYNTHETIC METALS
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2021
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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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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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Journal of Water Process Engineering
·
2023
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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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