ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
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2021
·Vol. 28
·期 23
·30312-30322
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IF 4.223
Wang Yingya,Zhang Hanbing,Yaseen Muhammad,Tong Zhangfa,Chen Ninghua,Shi Huazhen
In order to endow alkaline Ca-bentonite (ACB) with magnetic separation ability, simultaneously obtain better magnetic stability and stronger removal capacity of heavy metal cations; magnetic alkaline Ca-bentonite/carboxymethylcellulose-chitosan film (MACB/C-C) was prepared by organic modification of magnetic alkaline Ca-bentonite (MACB) using non-toxic carboxymethylcellulose and chitosan. Textural characterization results revealed that magnetic Fe 3 O 4 nanoparticles were successfully immobilized on ACB and modified with C-C. The functionalized layer of C-C concurrently enhanced the stability of Fe 3 O 4 and removal performances of heavy metal cations. Adsorption results indicated that MACB/C-C exhibited thorough separation from aqueous solution and greater uptake ability for Pb(II) and Cd(II) (483 mg·g −1 and 123 mg·g −1 ) than the nascent MACB (335 mg·g −1 and 76 mg·g −1 ), respectively, at pH 5 and 25 °C temperature. The adsorption of Pb(II) and Cd(II) on MACB/C-C mainly occurred via surface precipitation and complexation when pH > 2. MACB/C-C could be efficiently recycled with marginal decrease in adsorption capacity. The current approach credited to the convenient operation, simplified synthesis, and high efficiency of MACB/C-C could be deemed as a promising alternative for the removal of heavy metal cations from wastewater.
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JOURNAL OF SOILS AND SEDIMENTS
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2021
·Vol. 21
·期 7
·2540-2550
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IF 3.308
Yang Han,Ye Zhi,Feng Fang,Xu Nan,Yang Jing,Yao Zihan,Li Zuling,Chen Jianping
Purpose Lead (Pb(II)) can be accumulated in soil and transferred to humans via the food chain. Therefore, it is essential to improve Pb(II) immobilization during soil remediation. Materials and methods Nanosized zero-valent iron (nZVI) from green tea extract (tea polyphenols, TPs) was successfully synthesized as an additive reductant. Further, the nZVI was supported on montmorillonite (Mont), resulting in a GT-nZVI@Mont composite characterized by multiple techniques, including Zeta potential, SEM, TEM, XRD, and XPS. Moreover, the transport experiments and the toxicity characteristic leaching procedure (TCLP) were conducted to identify the optimum conditions (i.e., GT-nZVI@Mont dosage, Pb(II) concentration, and pH) for the remediation. Results and discussion The experimental results showed that the enhanced transportability of GT-nZVI@Mont was about 40% more than that of GT-nZVI. Meanwhile, Pb(II) immobilization was increased at various pH values (especially under anoxic conditions). The Pb(II) immobilization capacity of GT-nZVI@Mont was 900.8 mg∙g -1 (per unit of Fe content), which was significantly higher than 530.1 mg∙g -1 per unit of Fe content in GT-nZVI. Such enhancement could be ascribed to the synergistic effects of the wrapped TP around the Fe 0 core and the Mont interlayer support, capable of protecting the Fe 0 surface from further oxidation. When GT-nZVI@Mont reacted with the Pb(II) in soil, TPs’ unwrapped coverage increased the reaction sites of Fe 0 cores for Pb(II) reduction and adsorption. Conclusions GT-nZVI@Mont with sufficient transportability provided efficient in situ remediation of Pb(II) in contaminated soil at a wide pH range.
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JOURNAL OF ENVIRONMENTAL MANAGEMENT
·
2021
·
IF 6.789
Xin Zhao,Meng Li,Fuqiang Zhai,Yanling Hou,Rui Hu
Phosphate species can complex with nuclides and heavy metals from aqueous solutions strongly. The introduction of phosphate groups onto the surface of biochar sorbents (mostly <1.0 at.% of P) is highly desired. In this study, phosphate modified hydrochars (HTBs) were prepared through the hydrothermal carbonization of bamboo sawdust with various duration (2, 12, 24 h) in the presence of phytic acid (0–70 wt%). The results showed that the addition of PA with a low concentration of 10 wt% carbonized at 2 h generated hydrogen protons to etch the pristine sawdust, inducing the granulation of surfaces and a 5.5-fold enhancement of surface area. While HTBs carbonized with increasing PA concentrations (30–70 wt%) and longer duration (12 and 24 h) presented more carbonaceous particles with rising sizes from <100 nm to 2.5 μm, which should be due to the cross-linkage of dehydrated phosphate-containing organic carbon components to the matrix, enabling the resultful surface modification (maximum of 2.1 wt% of P). The uptake of U(VI), Pb(II) and Cd(II) on HTBs was investigated given various geochemical conditions including contact time, pH, ionic strength , humic acid and temperature. HTBs could capture U(VI), Pb(II) and Cd(II) efficiently from the ideal and simulated wastewaters, and be reused well after six recycles. This work opened a new strategy for the potential of phosphate-hydrochars in the aqueous remediation.
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JOURNAL OF MOLECULAR LIQUIDS
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2020
·
IF 5.065
Chen Wang,Guo Lin,Yunhao Xi,Xiteng Li,Zhen Huang,Shixing Wang,Jiling Zhao,Libo Zhang
A novel Zr-MOF adsorbent was synthesized by one-step method and was used to selectively adsorb Hg(II) and Pb(II) from wastewater. The adsorbent can reduce the concentration of mercury and lead to less than the national standard (Hg is 50 μg/L and Pb is 1 mg/L). The entire adsorption process conforms to the pseudo second-order kinetic and Hill isotherm models. At pH 4, the adsorbent removed more than 90% of mercury (to 22 μg/L) and lead (to 0.732 mg/L) in 10 min and 960 min, and the maximum adsorption capacity was 1080 mg/g and 510 mg/g, respectively. In addition, the practical application in wastewater proved that the adsorbent can selectively adsorb Hg(II) and Pb(II) from the mixed ion solution and it still meets national standards for wastewater discharge. The research of repeated experiments proves that the adsorbent can be used repeatedly. The adsorption mechanism was clarified by FTIR, XPS spectroscopy before and after adsorption, and density functional theory (DFT) calculation. In summary, the adsorbent is stable in aqueous solution and has great potential for the efficient removal of trace heavy metal ions (mercury and lead) in future treatment of wastewater.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2020
·
IF 5.162
Hongling Zhang,Jianzhe Ma,Fengyun Wang,Yuting Chu,Lei Yang,Mingzhu Xia
The carboxymethyl-chitosan-montmorillonite (CMC-MMT) organic-inorganic hybrid material was applied to adsorb Pb(II) and Congo red (CR) anionic dye from aqueous solution. Molecular dynamics(MD) simulation was carried out to reveal the mechanism of CMC hybrid MMT. The results suggested that CMC has been adsorbed on the interlayer space and surface of MMT, hydrogen bonds had been formed between hydroxyl & carboxyl groups of CMC with the surface of MMT, Van der Waals interaction was also existed, while amino groups of CMC hadn't obvious interaction with the surface of MMT. Batch experiments were executed to investigate the adsorption effect of CMC-MMT was compared with Na-MMT and CMC. The results showed that CMC-MMT exhibited the higher adsorption capacity than Na-MMT and CMC, The OH and COOH or NH 2 groups of CMC chains may serve as electrostatic interaction active sites and coordination sites, which improved the adsorption performance of CMC-MMT on Pb(II)，and the insertion of CMC enlarged the inter-layer space of MMT, resulting in more surface active sites in the CMC-MMT hybrid composite, which increased the adsorption of organic pollutant CR. The kinetic and isotherm studies indicated that the pseudo-second-order and the Langmuir model well described the adsorption equilibrium of Pb(II) and CR on CMC-MMT.
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RSC Advances
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2021
·Vol. 11
·期 47
·29590-29597
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IF 3.361
Chuanen Guo,Chengxiang Wang,Hongyan Sun,Dongmei Dai,Hongtao Gao
High-performance electrode modification materials play a crucial role in improving the sensitivity of sensor detection in electrochemical determination of heavy metals. In this study, a rGO/MoS2/CS nanocomposite modified glassy carbon electrode (GCE) was used to construct a sensitive sensor for detecting lead ions in tobacco leaves. The reduced graphene oxide (rGO) was used to increase the conductivity of the sensor, and the nano-flowered MoS2 could provide a large reaction specific surface area and a certain active site for heavy metal reaction. Chitosan (CS) was used to improve the enrichment ability of heavy metals and increase the electrocatalytic activity of electrode. Thus, an electrochemical sensor with excellent performance in reproducibility, stability and anti-interference ability was established. The stripping behavior of Pb(II) and the application conditions of the sensor were studied by square wave anodic stripping voltammetry (SWASV). The investigation indicated that the sensor exhibited high detection sensitivity in the range of 0.005–0.05–2.0 μM, and the limit of detection (LOD) was 0.0016 μM. This work can provide a fast and effective method for determination of Pb(II) in samples with low content, such as tobacco leaves.
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INORGANIC CHEMISTRY COMMUNICATIONS
·
2019
·
IF 1.795
Yaxiao Zhang,Chao Li,Yingchun Su,Wei Mu,Xiaojun Han
Heavy metal pollution causes serious health threat to humanbeings. Herein we fabricated a novel bismuth oxycarbide (BOC) modified glassy carbon electrode (GCE) for the simultaneous detection of cadmium and lead ions using differential pulse anodic stripping voltammetry (DPASV). The main factors influencing the detection performance, such as solution pH, deposition voltage and deposition time were optimized to be 4.5, −1.3v, and 700s, respectively. The detection limits for lead ions and cadmium ions were 4.30 μg/L and 3.97 μg/L, respectively. These detection limits are both lower than 5 μg/L for cadmium ions and 10 μg/L for lead ions national standards. The BOC modified GCE exhibits good selectivity and reliability for the detection of lead ions and cadmium ions. BOC/GCE may find great potential for heavy metal ions detection in real water sample.
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JOURNAL OF HAZARDOUS MATERIALS
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2019
·
IF 7.65
Jiujiang Ji,Guo Chen,Jun Zhao
To explore the effect of coexisted amino and thiol groups on adsorption of heavy metal, a novel magnetic nanoparticle was prepared by sequentially modification with (3-Chloropropyl) trimethoxysilan, polyetherimide, epichlorohydrin and thiourea. Subsequently, it was characterized by TEM, N 2 adsorption/desorption, FTIR Spectroscopy, zeta potential, and VSM. The maximum adsorption capacity for Pb 2+ , Cd 2+ and Cu 2+ reached 110.13 mg·g −1 , 40.23 mg·g −1 and 29.37 mg·g −1 , respectively. The adsorption of the magnetic nanoparticles with different surface group for heavy metals were compared, which indicated that the amino and thiol group played an important role in the adsorption of heavy metals. Especially, the adsorption capacity increased dramatically after modification with the thiol group, which was attributed to the synergistic coordination of −NH 2 and −SH. The adsorption kinetics is consistent with the quasi-second-order kinetics equation, and the adsorption thermodynamic process is consistent with the Langmuir isotherm equation. The effects of experimental conditions, such as pH, the concentration of metals, adsorption time and temperature, on adsorption of Pb 2+ were studied in detail. In addition, over 90% of removal rate was remained after 6 cycles. The magnetic nanoadsorbents was a promising nanoadsorbent with high adsorption speed, simultaneous adsorption of various heavy metals, strong anti-interference ability and reusability.
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CHEMICAL ENGINEERING JOURNAL
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2019
·
IF 8.355
Jingtao Bi,Xin Huang,Jingkang Wang,Ting Wang,Hao Wu,Jinyue Yang,Haijiao Lu,Hongxun Hao
In this work, to simultaneously remove organic dyes and Pb(II) from wastewater, a series of magnetic Fe 3 O 4 @C@TiO 2 -nanotube composites were designed and successfully synthesized via a new facile oil-phase cyclic magnetic adsorption (OCMA) method. The structural properties of the synthesized composites were investigated by different characterization methods systematically. It was found that Fe 3 O 4 was uniformly deposited on the inner walls of TiO 2 nanotubes. Although a Type III band alignment was formed in the catalysts, Fe 3 O 4 @C@TiO 2 -nanotube composites exhibited enhanced light absorbing ability and enlarged absorption edge due to efficient separation of h + and e − , which was verified by UV–Vis (Ultraviolet–visible) and PL (Photoluminescence) spectra. Decontamination experiments of 1FeCTi showed that more than 98% of RhB and about 92% of Pb(II) ions could be removed through adsorptive removal in the dark equilibrium period and further elimination during the illuminating period. The pseudo-first-order model, L-H model and adsorption-reaction model were established to describe the adsorption of Pb(II) in the dark, photodegradation of RhB and further elimination of Pb(II), respectively. A four-step mechanism was proposed to describe the decontamination process of Pb(II) during the illuminating period according to the final forms of Pb (Pb δ1 , Pb δ2 , Pb 0 and PbO). Finally, it was found that the photocatalytic activity would be maintained in the recycle experiments due to the existence of 1FeCTi@PbO heterostructure.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2019
·
IF 4.784
Xue Xue Liang,Xiao-Kun Ouyang,Songyan Wang,Li-Ye Yang,Fangfang Huang,Chao Ji,Xiaohong Chen
The performance of Fe 3 O 4 /attapulgite (APT) nanoparticles in Pb(II) adsorption from aqueous solutions could be improved by modifying the particles with aminopropyltriethoxysilane (APTS) and then combining with chitosan (CS) into beads. After preparing the APTS-Fe 3 O 4 /APT@CS beads, their surface morphology and crystal phases were analyzed by Fourier-transform infrared spectroscopy, scanning electron microscopy, and X-ray diffraction. The magnetic properties of APTS-Fe 3 O 4 /APT@CS were studied by a vibrating sample magnetometer, while their heat resistance and stability were characterized by thermal weight analysis. A recycling test and comparison of adsorption capacities were also carried out. The adsorption capacity of Fe 3 O 4 /APT was improved by the modification with APTS and CS. The adsorption process conforms to the pseudo-second-order kinetic and Langmuir adsorption isotherm models. The adsorption of Pb(II) reaches a maximum of 625.34 mg/g, which compares favorably with other reported adsorbents. The results show that APTS-Fe 3 O 4 /APT@CS is a promising hybrid adsorbent for effective removal of Pb(II) from water.
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ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2019
·Vol. 27
·期 5
·5108-5121
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IF 2.914
Fu Binbin,Xie Fencun
A novel cellulose microcrystalline-manganese dioxide nanocomposite (CMC-NMO) was synthesized by the redox reaction between potassium permanganate and ethanol based on cellulose microcrystalline. The cellulose microcrystalline (CMC) as support providing growth sites for the manganese dioxide nanowhiskers produced by the redox reaction and its application for Pb(II) and Cd(II) removal from aqueous was investigated. The characterization of as-synthesized material was revealed by various spectroscopic and microscopic techniques. Infrared-transform infrared (FITR) indicates that the incorporation of manganese oxide to CMC does not change the initial structure of it. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) data show that the manganese dioxide nanowhiskers with a few nanometers are uniformly dispersed on the surface of cellulose. Kinetics experiments reveal that Pb(II) and Cd(II) adsorption on CMC-NMO is a fast process and pseudo-second-order model fits the adsorption better. The maximum adsorption capacities of Pb(II) and Cd(II) obtained from the Langmuir model are 290.8 mg/g and 67.4 mg/g, respectively. The mechanism is mainly attributed to surface complexation and electrostatic attraction by energy dispersive analysis of X-rays (EDAX), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) analysis. In addition, depth removal experiments show that the residual concentrations of Pb(II) and Cd(II) in natural water after adsorption are lower than 0.01 mg/L. The regeneration and cyclic utilizing studies indicate that CMC-NMO has good adsorption stability. Therefore, the results indicate that this material can be employed as a potential adsorbent for current serious Pb(II) and Cd(II) pollution caused by industrial emissions.
Graphical abstract
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Polymers
·
2018
·Vol. 10
·期 7
·750
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IF 2.935
Nan Wang,Li-Ye Yang,Yang-guang Wang,Xiao-kun Ouyang
In this work, a tetraethylenepentamine (TEPA)-grafted metal-organic framework material (MIL-101) was synthesized. The introduction of TEPA increased the abundance of functional groups on the MIL-101. As a powdery adsorbent, MIL-101-TEPA can be difficult to separate. In order to solve this problem, we combined MIL-101-TEPA with sodium alginate (SA) and injected the mixture into a CaCl2solution to solidify the powder into beads with a particle size of 3 mm. The easily recovered adsorbent was applied to the adsorption of Pb(II) from water. The structure and characterization of the adsorbent were investigated through scanning electron microscope (SEM), Fourier-transform infrared spectroscopy (FTIR), X-Ray diffraction (XRD), thermogravimetric analysis (TGA), and X-ray photoelectron spectroscopy (XPS). We also optimized the adsorption conditions. The results of the study showed that the adsorption process was chemisorptive and endothermic in nature. The maximum adsorption capacity of the composite beads was 558.6 mg/g. Meanwhile MIL-101-TEPA@CA showed good repeatable utilization.Keywords:sodium alginate;functional MIL-101;composite beads;adsorption;Pb(II)
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