MICROCHIMICA ACTA
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2018
·Vol. 185
·期 5
·1-9
·
IF 5.705
Han Xiujuan,Meng Zuchao,Zhang Hongfang,Zheng Jianbin
Various carbon nanomaterials for use in anodic stripping voltammetric analysis of Hg(II), Cu(II), Pb(II) and Cd(II) are screened. Graphene, carbon nanotubes, carbon nanofibers and fullerene (C 60 ), dispersed in chitosan (Chit) aqueous solution, are used to modify a glassy carbon electrode (GCE). The fullerene-chitosan modified GCE (C 60 -Chit/GCE) displays superior performance in terms of simultaneous determination of the above ions. The electrodes and materials are characterized by electrochemical impedance spectroscopy, cyclic voltammetry, scanning electron microscopy, Raman spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The excellent performance of C 60 -Chit/GCE is attributed to the good electrical conductivity, large surface area, strong adsorption affinity and unique crystalline structure of C 60 . Using differential pulse anodic stripping voltammetry, the assay has the following features for Hg(II), Cu(II), Pb(II) and Cd(II), respectively: (a) Peak voltages of +0.14, −0.11, −0.58 and − 0.82 V (vs SCE); (b) linear ranges extending from 0.01–6.0 μM, 0.05–6.0 μM, 0.005–6.0 μM and 0.5–9.0 μM; and (c), detection limits (3σ method) of 3 nM (0.6 ppb), 14 nM (0.9 ppb), 1 nM (0.2 ppb) and 21 nM (2.4 ppb). Moreover, the modified GCE is well reproducible and suitable for long-term usage. The method was successfully applied to the simultaneous determination of these ions in spiked foodstuff.
Compared with graphene, carbon nanotubes and carbon nanofibers, an electrode modified with fullerene in chitosan electrode displays superior performance for the simultaneous anodic stripping voltammetric detection of Hg(II), Cu(II), Pb(II) and Cd(II).
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Scientific Reports
·
2017
·Vol. 7
·期 1
·1-11
·
IF 4.259
Wang Yaoguang,Wu Di,Wei Qin,Wei Dong,Yan Tao,Yan Liangguo,Hu Lihua,Du Bin
In this study, branched polyethylenimine (PEI) enhanced magnetic carboxymethyl chitosan (MCMC-PEI) was synthesized and applied as adsorbent for the rapid removal of Pb(II) from aqueous solution. The successful synthesis of the adsorbent was proved by scanning electron microscope (SEM), Fourier transform infrared spectrum (FTIR) and X-ray powder diffraction (XRD). Simultaneously, the effect of the parameters such as initial concentration, adsorbent mass and pH of the solution on the removal of Pb(II) was studied by using response surface methodology (RSM). And central composite design (CCD), which is a widely used form of RSM, was employed in the experimental design procedure. The adsorption results revealed that the adsorption process could reach equilibrium rapidly within 10 min. Furthermore, the adsorption kinetic data could be well described by pseudo-second order model. The maximum adsorption capacity was 124.0 mg/g according to the Langmuir-Freundlich model, which fitted the adsorption isotherm of Pb(II) better than Langmuir model and Freundlich model, respectively. Thermodynamic studies (Δ G < 0, Δ H < 0, Δ S > 0) implied a spontaneous and exothermic process in nature. Meanwhile, the fabricated adsorbent exhibited excellent reusability. Therefore, the excellent adsorption property of MCMC-PEI made it a promising application in water treatment.
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Journal of Cleaner Production
·
2017
·
IF 5.715
Nan Zhou,Honggang Chen,Qiuju Feng,Denghui Yao,Huanli Chen,Haiyan Wang,Zhi Zhou,Huiyong Li,Yun Tian,Xiangyang Lu
The acidic environment has been confirmed to have significant influence on the biochar products through hydrothermal carbonization . To investigate the effect of H 3 PO 4 on the surface properties and adsorption mechanisms of the biochar, fresh banana peels were used as feedstock and transformed into hydrochars under the catalysis of H 3 PO 4 with concentration ranges from 0% to 50%wt. The addition of H 3 PO 4 greatly impacted the physicochemical properties of the as-obtained hydrochars, such as carbonization degrees, pH values, amount of surface acidic functional groups and then further affected the adsorption mechanisms of lead ions on those hydrochars. Hydrochars catalyzed by H 3 PO 4 with higher concentration showed higher degree of carbonization, lower value of pH and fewer amount of acidic functional groups, while lower content of H 3 PO 4 could not completely catalyze the degradation reactions and resulted in larger quantity of intermolecular locked oxygen containing groups that could not be participated into the adsorption process . Among all six samples, hydrochar generated in 30%wt H 3 PO 4 exhibited the best adsorption property of 241 mg g −1 , possibly due to the largest concentration of the acidic functional groups on the surface rather than in the intermolecular structure of the carbon. It had been confirmed that the adsorption mechanisms were the combination of surface complexation, cationic exchange and part of precipitation. Hydrochars derived from fresh banana peel via hydrothermal carbonization catalyzed by phosphoric acid could be excellent adsorbents for lead removal in aqueous environments .
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Science China-Chemistry
·
2013
·Vol. 56
·期 5
·567-575
·
IF 1.327
Xiang Ting,Zhang ZuLei,Liu HaiQing,Yin ZhengZhi,Li Lei,Liu XiaoMing
Nanofiber membranes from the composite of cellulose acetate/polyvinylpyrrolidone were prepared using electrospinning technique. After treated with water and alcoholic KOH to remove partially polyvinylpyrrolidone and deacetylate the cellulose acetate, the membranes were further functionalized with thiol groups using thioglycolic acid. Related materials were characterized using infrared and thermogravimetric analysis. And the results showed that the membranes were success of functionalisation. Then the nanofiber membranes were used in the sorption-desorption process. The effects of pH, contacting time and adsorption capacity of nanofiber membranes were studied against Cu(II), Cd(II) and Pb(II) ions. And the maximum adsorption capacities of Pb (II), Cu (II), and Cd (II) ions were estimated at 30.96, 19.63, 34.70 mg g −1 . Our results suggested that the adsorption behaviour of metal ions could be described using Langmuir model. Their adsorption kinetics was in agreement with the model of pseudo-second order, suggesting chemical adsorption as the rate-limiting step of the adsorption mechanism. The durability of the thiol-functionalized cellulose nanofiber membranes was also evaluated by repetitive adsorption-desorption.
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SCIENCE OF THE TOTAL ENVIRONMENT
·
2024
·
IF 8.2
Lian Xia,Feng Luo,Xiaojuan Niu,Yue Tang,Yuangen Wu
Pb(II) is a prevalent heavy metal ion classified as a 2B carcinogen. Excessive intake of Pb(II) in the human body can damage the central nervous system, kidneys, liver, and immune system, leading to permanent brain damage, anemia, and cancer. Colorimetry can be applied to rapidly determine Pb(II) residues, but there are still many challenges in the accuracy and sensitivity of detection. Based on the inhibitory impact of Pb(II) on the oxidase-like activity of octahedral silver oxide (Ag 2 O), a colorimetric sensor with smartphone-assisted analysis for the Pb(II) detection was first developed. Herein, it has been found that Pb(II) can adsorb onto the surface of octahedral Ag 2 O, hindering the production of O 2 − in the reaction system. This ultimately results in the suppression of oxidase-like activity, leading to a lighter purple appearance of the colorimetric reaction solution. The sensor exhibits a high degree of sensitivity and a limit of detection (LOD) for Pb(II) was calculated as 2.2 μg L −1 . Hence, the developed colorimetric sensor with high sensitivity, excellent specificity, and high tolerance to sodium ions is hopeful to have practical applications in Pb(II) detection in environmental water samples. Moreover, the sensor will provide a novel strategy for heavy metal ion detection and other substances.
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FOOD CHEMISTRY
·
2024
·
IF 8.5
Zhanqiu Tang,Xinyi Feng,Hongyuan Tian,Junhua Wang,Weidong Qin
A novel method is introduced for extracting and enriching Cd(II) and Pb(II) from edible oils using glutathione disulfide (GSSG) as both an extractant and a phase-separation agent. The ions in the oils were initially extracted into an aqueous solution containing GSSG. After mixing the solution with acetonitrile at the appropriate volume ratio, a new phase formed, resulting in enrichment of the analytes. The experimental conditions were optimized using response surface methodology with a central composite design. Under optimal conditions, the method offered a combined enrichment factor of >660, with combined extraction efficiencies of 84.31% and 83.35% for Cd(II) and Pb(II), respectively. Finally, the method was conjugated to capillary electrophoresis to determine Cd(II) and Pb(II) in edible oil samples, with detection limits of 0.45 and 1.24 ppb, respectively. In comparison to traditional approaches, the GSSG-based method demonstrates rapidity, efficiency, and recyclability in extracting heavy metal ions from complex matrices.
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JOURNAL OF FOOD COMPOSITION AND ANALYSIS
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2024
·
IF 4
Jiangxiong Zhu,Hao Yin,Yidong Xin,Lumei Wang,Xueqing Geng,Haiyun Zhao,Yun Deng
A novel structure-switching “turn-on” fluorometric aptasensor was developed for simultaneous detection of Hg(II) and Pb(II) in grapes, broccoli, and cabbage. The sensing mechanism utilizes fluorescence resonance energy transfer (FRET) between a FAM-labeled aptamer (FAM-Apt) and a BHQ1-labeled complementary strand (CS-BHQ1). In the absence of target ions, FAM-Apt and CS- BHQ1 bind through complementary base pairing, bringing FAM and BHQ1 into close proximity, which induces FRET and quenches FAM’s fluorescence. Target ion binding induces a conformational change in the FAM-Apt, disrupting FRET and restoring fluorescence. Optimized parameters include reagent addition sequence, Apt and CS concentrations, incubation times, buffer conditions, and salt concentrations. Under optimized conditions, the aptasensor achieved limits of detection (LODs) of 2.29 μg/L for Hg(II) and 0.24 μg/L for Pb(II), much lower than the regulatory limits for fruits and vegetables, and the limits of quantification (LOQ) for food samples were 6.02 μg/kg and 2.07 μg/kg, respectively. Furthermore, the constructed aptasensor could rapidly complete detection within 22.5 min and demonstrated high selectivity against interfering ions. Spiked sample recoveries ranged from 98.07-104.12% for Hg(II) and 89.23-105.46% for Pb(II), with relative standard deviations of 0.95-5.64% and 1.21-14.53%, respectively. This aptasensor provides a sensitive, rapid, and cost-effective alternative to conventional detection methods.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2024
·
IF 3.8
Alhadi Ishag,Weiyu Zhu,Yanxue Yue,Rongbo Hou,Bo Zhang,Yubing Sun
The simultaneous adsorption of U(VI), Pb(II), and humic acid (HA) in water solutions on a nanoscale zerovalent iron/molybdenum disulfide (nZVI/MoS2) composite was investigated using batch, spectroscopic, and modeling techniques. An increased removal of U(VI) and Pb(II) and a gradual decrease in HA removal on nZVI/MoS2 was observed with increasing pH from 2.0 to 7.0. The adsorption capacities of U(VI), Pb(II), and HA under ternary systems were 57.72, 40.43, and 55.43 mg/g (298 K, pH 4.0), respectively. In addition, nZVI/MoS2 exhibited good regeneration due to the high surface area and uniform distribution of nZVI. The interaction mechanism was demonstrated to be inner-sphere surface complexation by XPS analysis and surface complexation modeling (SCM). The presence of Pb(II) and HA inhibited U(VI) reduction into U(IV) by nZVI according to XPS analysis; meanwhile, two inner-sphere complexation reactions (weak and strong sites) rather than redox reactions were demonstrated by SCM. These findings showed that nZVI/MoS2 could be used as an efficient adsorbent for the high elimination of radionuclides, heavy metals, and organics in actual compound pollution of wastewater.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2025
·
IF 5.4
Xuejiao Liu,Beibei Pan,Zhiwei Li,Poonnawit Hanphaiboon,Yin Wang
Activated carbon supported nanoscale zero-valent iron (NZVI/AC) has been proved to be versatile for removing several kinds of contaminants from environmental matrix. The structural properties of NZVI/AC composites play a crucial role in determining both the decontamination efficiency and adsorption capacity of these materials. However, studies relevant to structural evolution and corresponding manipulation routes for AC-supported NZVI are still scarce. Herein, AC-supported NZVI were prepared under different synthesis conditions followed by characterizing them using several techniques and evaluating their reactivity toward heavy metal in aqueous solution. NZVI/AC synthesized under different molecular weight of PEG and m AC :m Fe possessed a similar removal efficiencies of Pb(II) from aqueous solution, meanwhile, NZVI/AC synthesized with a suitably prolonged time at n BH4 :n Fe = 8.0 exhibited obvious enhancement for Pb(II) removal from aqueous solution. As for structural evolution of AC-supported NZVI, results show that the crystallization was more complete, the shape was converted from needle to sphere, the particle size was becoming smaller, the particle distribution was more homogeneous, the specific surface area was smaller, and the surface oxidation was lower as suitably increasing m AC :m Fe , n BH4 :n Fe , and reaction time. The size and density of iron precursor by complexation of PEG and Fe 2+ , and ratio of nuclei formation to growth values are essentially responsible for manipulating structure of AC-supported NZVI. Spherical AC-supported NZVI with higher iron content based on smaller particle size, uniform distribution, and lower surface oxidation in one is responsible for significant enhancement of Pb(II) removal rate and capacity thanks to higher surface reactivity, more accessible surface-active sites, and faster electron transfer from core to shell of iron. This study would provide a new insight into comprehending manipulation mechanism for the key structure of AC-supported NZVI composites for aquatic remediation.
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CHEMICAL ENGINEERING SCIENCE
·
2025
·
IF 4.3
Xiaoxiao Yu,Yuanhong Tang,Tong Shao,Xiaohan Xu,Hong Xiao,Xiaojing Wang,Hong Peng,Xiaohui Lu,Shihuai Deng,Gang Yang,Yanzong Zhang,Zhenxing Zeng
The selective removal of highly toxic heavy metal ion Pb(II) from wastewater is of significant importance to the ecological environment and human health, while the development of high performance adsorbents for selective Pb(II) adsorption remains a big challenge. Herein, a cleverly designed heavy metal adsorbent over potassium and cyano modified carbon nitride (KCCN) is proposed, exhibiting excellent performance toward Pb(II) selective removal. The amino and cyano groups in KCCN are found high affinity to that of Pb(II) in such a potassium doped system, as a result showing an excellent Pb(II) selective adsorption performance in the presence of various ions without obviously changing the distribution coefficient K d value. In addition, the adsorption process is found to follow the Langmuir isotherm model and pseudo-second-order kinetic, with a maximum adsorption capacity for Pb(Ⅱ) of 293.26 mg/g. Furthermore, no obvious adsorption capacity drop is found after five cycles of Pb(II) adsorption processes, demonstrating the high reusability on Pb(II) removal.
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JOURNAL OF MOLECULAR STRUCTURE
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2025
·
IF 4.7
Abdelazeem S. Eltaweil,Ahmed E. Awad,Eman M. Abd El-Monaem,Azza M. Shaker,Gehan M. El-Subruiti
The growing issue of Pb 2+ ions contamination in marine environments necessitates the development of effective adsorbents to significantly mitigate this ecological challenge. In response, a novel composite material comprising layered double hydroxide (LDH), boron nitride (BN), and tin ferrite (SnFe 2 O 4 ) was synthesized for the removal of Pb 2+ ions. The synthesized SnFe 2 O 4 /BN/NiAl-LDH composite was characterized using FTIR, XRD, ZP, SEM, and XPS techniques. Pb 2+ ions removal reached equilibrium within 30 minutes, with a removal efficiency of 95.42%. Pb 2+ removal efficiency increased progressively in the following order based on the data: SnFe 2 O 4 /BN/NiAl-LDH (1:1) > SnFe 2 O 4 /BN/NiAl-LDH (3:1) > SnFe 2 O 4 /BN/NiAl-LDH (1:3). Furthermore, the experimental data were consistent with the Langmuir and Freundlich isotherms, as well as the pseudo-second-order kinetic model, with a maximum adsorption capacity of 434.8 mg/g. Notably, the composite retained over 70% removal efficiency after five cycles, demonstrating its efficient recyclability. In summary, SnFe 2 O 4 /BN/NiAl-LDH exhibits rapid and efficient adsorption, easy separation, and excellent recyclability.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2024
·
IF 7.7
Yiwen Zhang,Anwen Li,Tian Tian,Xunyong Zhou,Yutong Liu,Min Zhao,Longshan Zhao
A kind of new magnetic oyster shell (OS) composite (OS-Fe 3 O 4 @SiO 2 @NH 2 @PEI) was synthesized and used as an adsorbent to remove carmine (CM), sunset yellow (SY) and Pb (II) from water. Firstly, Fe 3 O 4 magnetic nanoparticles were introduced on the surface of waste oyster shell powder, then amino silanization was used to improve the stability of the material, and finally polyethylenimide (PEI) was grafted by Schiff base reaction. The composite was characterized by FT-IR, SEM, EDS, XPS , VSM, BET, TEM and zeta potential . The effects of adsorbent dosage and initial solution pH on the three samples were investigated by adsorption experiments. The adsorption kinetics and isotherms were investigated in depth under the best experimental conditions. The composite adsorbent not only selectively removed anionic azo dyes, but also had good recycling. In addition, OS-Fe 3 O 4 @SiO 2 @NH 2 @PEI still had good performance in mixed samples. These results indicated that OS-Fe 3 O 4 @SiO 2 @NH 2 @PEI was successfully used for the removal of a wide range of anionic dyes and heavy metal ions from the environment, and provided a new strategy for recycling waste.
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