JOURNAL OF ELECTROANALYTICAL CHEMISTRY
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2021
·
IF 4.464
Baitong Niu,Biying Yao,Meihua Zhu,Hongxu Guo,Shaoming Ying,Zhangxu Chen
A fern leave-like structure metal-organic frameworks (MOFs), MIL-47(as) has been fabricated by a simple one-pot hydrothermal reaction and characterized by a variety of means, such as X-ray diffraction, Fourier transform infrared spectroscopy, micro-morphology analysis, X-ray photoelectron spectroscopy and specific surface area and pore size distribution. The as-prepared MOFs were found to be an effective material for the selective electrochemical detection of microgram levels of Pb(II), Cu(II) and Hg(II) in aqueous solution performed by differential pulse voltammetry. The electrochemical properties and applications of the modified electrode were also studied, in which operational parameters such as pH, deposition potential, and deposition time, were optimized to detect trace amounts of Pb(II), Cu(II) and Hg(II) ions. The as-prepared electrode not only has good stability and repeatability, but also has good practical detection ability.
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FOOD CHEMISTRY
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2021
·
IF 7.514
Hui Cao,Denghui Meng,Xutao Liu,Tai Ye,Min Yuan,Jinsong Yu,Xiuxiu Wu,Yan Li,Fengqin Yin,Fei Xu
A novel dual-frequency ultrasound-assisted enzymatic digestion (DUED) technique was used to extract Pb(II) from certified reference materials (CRMs) of wheat flour. Following this, the interactions of Pb(II) with wheat proteins were investigated to provide evidence for the selection of enzyme species. The results showed that the simultaneous use of α-amylase and flavourzyme resulted in the recovery of 97.9% of Pb(II) in 6 min under a 40 kHz ultrasonic bath combined with a 20 kHz ultrasonic probe. The exopeptidase activity of the flavourzyme was found to be the main contributor to the extraction of Pb(II) from the CRMs. Additionally, the proposed method exhibited a low detection limit (8.2 ng/g) and high recoveries of real samples (93.4%-112.2%) with RSD less than 7.33%. Furthermore, the oxygen-containing groups of wheat proteins, the nitrogen-containing groups of albumins and globulins, and the sulfur-containing groups of gliadins and glutenins were found to offer coordination sites for Pb(II).
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Journal of Cleaner Production
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2020
·
IF 7.246
Dezhi Zhao,Zheng Wang,Shuang Lu,Xianming Shi
Eco-friendly adsorbents for removing heavy metals from wastewater are urgently needed. This work fabricated an amidoxime-modified polypropylene (PP) fiber as a cost-effective and recyclable adsorbent to remove heavy metals. The laboratory study aimed to evaluate the competitive adsorption of Cu(II), Pb(II) and Zn(II) onto AO-PP fiber in aqueous solutions. The adsorption isothermal data fitted the Langmuir isotherm well, and the maximum adsorption capacities (mg/g) were in the order of Cu (47.23)>Pb (45.64)>Zn (37.78) when applying the Langmuir isotherm at pH 5.0. Adsorption equilibrium could be reached within 90 min. The adsorption was pH-dependent and followed the pseudo-second-order model well. The adsorption can be explained by the coordination between N- and O-containing groups and the metallic ions. Metallic ion affinity, steric hindrance , and covalent index were the main factors affecting the competitive adsorption behavior. Regeneration experiments revealed that the obtained adsorbent maintained favorable adsorption capacity even after 20 cycles. Cement mortars incorporating the metal-adsorbed fiber exhibited improved mechanical properties and satisfactory leaching performance. This work experimentally validated the effective use of AO-PP fiber to capture heavy metals from wastewater as well as subsequent sequestration of the recycled fibers in a suitable material matrix , providing a new reference for heavy metal harvesting and final disposal.
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INORGANIC CHEMISTRY
·
2021
·
IF 5.165
Zhe Dai,Yi-Gang Chen,Yao Guo,Fang Wang,Yuan-Yu Yang,Xian-Ming Zhang
The design of material by chemical and/or crystalline modification of a classic structure model benefits not only the optimized physical properties but also the controllability and efficiency. Herein, a new nonlinear-optical (NLO) beryllium borate crystal, Sr2Pb(BeB5O10)(BO3) (SPBBO), is successfully designed and synthesized by chemical and crystalline modification of the perovskite-like K3B6O10Cl NLO crystal. SPBBO displays a 3D BeB5O103– open-framework structure composed of interconnecting BeB5O13 groups with filled cationic Sr/Pb and anionic BO3 groups, which exhibits the striking enhancement of the second-harmonic-generation (SHG) response (8 × KDP) and birefringence (0.10) compared to the parent model. Replacement of K by Sr and Pb with a lone pair and replacement of Cl by conjugated BO3 result in the synergistic conjugation of Pb with host BeB5O103– and filled BO3 groups, contributing to the striking enhancement of the SHG and birefringence. Single-crystal measurements show that SPBBO has a short UV absorption edge of 280 nm with a wide energy band gap of 4.35 eV and an outstanding laser-induced resistant behavior with a remarkably high laser-induced damage threshold of 2100 MW cm–2. The excellent properties indicate that the SPBBO crystal is a very promising UV NLO functional material.
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ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2019
·Vol. 26
·期 32
·33427-33439
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IF 2.914
Wang Zongwu,Wu Qing,Zhang Jing,Zhang Huan,Feng Jinglan,Dong Shuying,Sun Jianhui
The efficient removal of heavy metals from aqueous environment is imperative and challenging. A novel ternary composite constructed of diaminopyridine polymers, graphene oxide, and ferrite magnetic nanoparticles was designed by a facile in situ polymerization strategy for the removal of Pb(II) from aqueous solution. Detailed characterization of morphological, chemical, and magnetic properties was employed systematically to confirm the formation of the composite material. Batch adsorption experiment studies suggested that the composite was an excellent adsorbent for Pb(II) which was easily collected after use via exposure to an external magnetic field for 30 s. The effects of different parameters such as solution pH, adsorbent dosage, contact time, initial Pb(II) concentration, temperature, and co-existing ions were examined. The maximum adsorption capacity at pH = 5 was estimated to be 387.2 mg g −1 at 298 K by the Langmuir isotherm model, accompanied by favorable adsorption recyclability according to the investigation of regeneration experiments. Thermodynamic studies revealed that the Pb(II) adsorption via our ternary composite was endothermic and spontaneous. The corresponding removal performance for effluent containing Pb(II) from the battery industry was successfully examined. The present results indicated that our designed adsorbent is beneficial to the practical Pb(II) removal in wastewater purification.
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CARBOHYDRATE POLYMERS
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2020
·
IF 7.182
Qi Wu,Hui He,Hang Zhou,Fei Xue,Hongxiang Zhu,Shile Zhou,Lei Wang,Shuangfei Wang
A novel multiple active sites cellulose-based adsorbent (MCC/TEPAA-BCTTC) with a high density of multiple active adsorption sites (N, O, S) was prepared by using epichlorohydrin cross-linking microcrystalline cellulose (MCC) with tetraethylenepentamine (TEPA), followed by grafting with bis(carboxymethyl) trithiocarbonate (BCTTC). It was shown that the removal rates of MCC/TEPAA-BCTTC for Pb(II) (1 mg/L), Cu(II) (3 mg/L) and Cr(VI) (1 mg/L) reached 100 %, 98 % and 99 %, respectively, and the remaining concentration after adsorption reached the United States Environmental Protection Agency (US EPA) standards for Pb(II) and Cu(II) and the China integrated wastewater discharge standard for Cr(VI). These results indicate that the high removal rate of MCC/TEPAA-BCTTC for removing anionic and cationic heavy metal ions in low-concentration mixed heavy metal ions environments was mainly due to the high density of multiple adsorption sites that act via multiple cooperative mechanisms.
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Journal of Environmental Chemical Engineering
·
2019
·
IF 0
Sefiu A. Rasaki,Tiju Thomas,Minghui Yang
Due to high surface area and large pore volume, nanostructure zinc oxides/its composites have gained a lot of research interests for heavy metal removal from water. Low stability of the ZnO at low and high pH is however a problem. In this work, ZnO@MgO, ZnO and MgO are synthesized via co-precipitation, followed by calcinations. The samples show remarkable removal of Pb(II) from water when compared to commercial samples; the best results is obtained using ZnO@MgO which exhibit adsorption capacity of 250 mg g −1 equivalent to 100% removal capacity. The optimum removal capacity is retained in a wide range of pH (i.e. pH 6–9) at temperature 30 °C. Low adsorption capacity coupled with low stability in acidic condition; a problem associated with ZnO-based adsorbents when it is being used for the removal of heavy metals from water/wastewater; often prevents this system from being practically used; is overcome here. The ZnO@MgO adsorbent shows chemical stability over wide range of pH(2–9). The adsorption is chemisorptive in nature, endothermic and evidently aided by high surface heterogeneity (△H° ˜25 kJ mol-1 and △S°˜110.6 J mol −1 K −1 ). Appreciable adsorption capacity over wide range of pH-value, high recovery and reusability results from nanosphere morphology of the composite sample; all these novel properties are attributed to the strong electronic coupling effect between MgO and ZnO. This work is expected to spur further research on ZnO-based composite materials in allied areas, including (i) mitigation of atmospheric pollution and (ii) water treatment processes.
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BIORESOURCE TECHNOLOGY
·
2019
·
IF 6.669
Jianhong Ma,Tong Li,Yutang Liu,Tao Cai,Yuanfeng Wei,Wanyue Dong,Hui Chen
In this study, lignin extracted from rice husk was used to synthesis double network hydrogel adsorbent, named RH-CTS/PAM gel. RH-CTS/PAM gel exhibited macroporous structure and high buried water content, which gave rise to the exceptional adsorption performance. As results, in individual systems, the equilibrium time of Pb(II), Cu(II) and Cd(II) with initial concentration of 200 mg/L could be reached within 10 min, with the theoretical maximum adsorption capacity of 374.32, 196.68 and 268.98 mg/g, respectively. The adsorption rate and capacity of Pb(II), Cu(II) and Cd(II) in multicomponent systems were lower than that of individual systems. However, in a few cases of ternary system, higher adsorption rate and capacity was observed compare to binary systems. Adsorption mechanism indicated that both oxygen-containing and nitrogen-containing functional groups played a dominant role during the adsorption process, and mainly through chemical interaction along with a small amount of physical interaction.
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COLLOID AND POLYMER SCIENCE
·
2014
·Vol. 292
·期 9
·2157-2172
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IF 2.41
Chen Xing Juan,Cai Jian Chong,Zhang Zheng Han,Liu Li Jia,Yang Guang Lei
A novel cross-linked chitosan-poly(aspartic acid) chelating resin was synthesized by combining chitosan and poly(aspartic acid) derivative with crosslinker. The structure and morphology of the resin containing disulfide bonds were characterized by 1 H NMR, FT-IR, Raman spectra, and SEM. Adsorption of Pb(II) and Hg(II) from aqueous solution by the resulted chelating resin was investigated in batch techniques. The result of the Raman spectra suggests that the disulfide bonds in the resin also play an important role in the adsorption of Pb(II) and Hg(II). The kinetic data were fitted to pseudo-first-order, pseudo-second-order, and intraparticle diffusion models, which is suggestive of following closely the pseudo-second-order kinetic model. Equilibrium data were fitted to Langmuir, Freundlich, and D–R isotherm models. The results of equilibrium isotherm reveal that the empirical Langmuir equation provides an accurate description of the experimental data under the studied concentration range. In addition, thermodynamic and regeneration properties of the adsorbent were also studied.
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WATER AIR AND SOIL POLLUTION
·
2016
·Vol. 227
·期 4
·1-11
·
IF 1.551
Ren Huixue,Jiang Jiahui,Wu Daoji,Gao Zhimin,Sun Youmin,Luo Congwei
Selective adsorption of Pb(II) and Cr(VI) by surfactant-modified and unmodified zeolites is discussed in this paper. The influences of pH, ionic strength, temperature, and adsorption time on Cr(VI) and Pb(II) adsorption are studied, The characteristics of the surface and inner structures of zeolites before and after modification are analyzed through infrared spectroscopy, scanning electron microscopy, X-ray diffraction, Brunauer–Emmett–Teller analysis, and zeta potential measurement. Results show that the characteristics of electric charge on the zeolite surface had changed after modification, which resulted in selective adsorption of Cr(VI) and Pb(II). Moreover, kinetic study reveals that adsorption by the different zeolites coincides with the Langmuir model and pseudo-second-order kinetic equation. The intraparticle diffusion equation proves that the Cr(VI) adsorption is mainly electrostatic, whereas Pb(II) adsorption proceeds via intrapore and electrostatic adsorption on the zeolite surface. This difference in mechanisms endows selectivity of metal ion adsorption by the modified zeolites. This study provides a reference on zeolite modification for use in various applications, such as wastewater treatment.
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JOURNAL OF ENVIRONMENTAL MANAGEMENT
·
2024
·
IF 8
Tao Chen,Guangzhu Cao,Yi Qiang,Yanfeng Lu,Ronggao Qin,Wan Xu,Yiming Xie,Ruoyu Mao
The modified walnut shell biochar (WBC) was prepared through zinc-iron bimetallic oxide modification (ZF@WBC) at 600 °C under oxygen-limited conditions in this study. Through adsorption experiments, characterization analyses, and density functional theory (DFT) calculations, the adsorption properties of ZF@WBC to Pb (II) were investigated and the mechanism underlying such adsorption was elucidated. Characterization results showed that the surface area (375.9709 m 2 /g) and total pore volume (0.205319 cm 3 /g) of ZF@WBC were significantly greater than those of walnut shell biochar. The maximum adsorption capacity of ZF@WBC for Pb (II) was found to be 104.26 mg/g, which is 2.57 times higher than that of WBC according to the adsorption experiments conducted. The observed adsorption behavior followed both the pseudo-second-order (PSO) kinetic model and Langmuir isothermal adsorption model, suggesting that chemisorption plays a major role in the absorption process. Based on SEM, XRD, XPS, FTIR characterizations along with DFT calculations performed in this study, it can be concluded that surface complexation, ion exchange, electrostatic attraction, physical absorption are among the main mechanisms responsible for absorption of Pb (II) by ZF@WBC. Furthermore, even in the presence of interfering ions at different concentrations, ZF@WBC exhibited a removal rate above 70% for Pb (II). Therefore, ZF@WBC has great potential as an effective absorbent for removing Pb (II) from wastewater, while also offering opportunities for biomass waste resource utilization.
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Analytical Methods
·
2017
·Vol. 10
·期 1
·51-58
·
IF 1.9
Xiao-Li Du,Tian-Fang Kang,Li-Ping Lu,Shui-Yuan Cheng
A novel electrochemiluminescence (ECL) biosensor based on CdSe@CdS quantum dots (QDs) functionalized MoS2 modified electrode was developed for sensitive detection of Pb(II) using HRP-mimicking DNAzyme biocatalytic precipitation (BCP) for ECL signal quenching. Polycationic poly(diallyldimethylammonium chloride) (PDDA) and negatively charged QDs were adsorbed on the surface of MoS2, in sequence, to form the MoS2–QDs composites, which were employed as a matrix for the immobilization of the G-rich DNA strand, i.e., T30695. The MoS2–QDs were characterized by UV-vis absorption spectroscopy, fluorescence spectroscopy, energy dispersive spectrometry, transmission electron microscopy, and field emission scanning electron microscopy. CdSe@CdS QDs can produce an ECL signal using 0.1 M K2S2O8 as a co-reactant. T30695 can combine with Pb(II) ions to form a stable parallel G-quadruplex. The G-quadruplex can further combine with hemin to form DNAzyme, which can catalyze H2O2 and oxidize 4-chloro-1-naphthol (4-CN) to produce an insoluble precipitation of benzo-4-chlorohexadienone on the surface of the sensor. When the concentration of Pb(II) in the solution was increased, more of DNAzyme was generated and subsequently more 4-CN molecules were oxidized catalytically, leading to a decrease of the ECL signal. Using this quenching strategy, the ECL signal of the biosensor was linearly dependent on the logarithm of the Pb(II) concentration ranging from 1.0 × 10−15 to 1.0 × 10−11 M with a detection limit of 0.98 f M. The stability and selectivity of the sensor were also investigated. The sensor was applied in the determination of Pb(II) in the real water samples and satisfactory results were obtained.
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