INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2021
·
IF 6.953
Zhiying Shao,Jilai Lu,Jian Ding,Fengjiao Fan,Xinyang Sun,Peng Li,Yong Fang,Qiuhui Hu
Chitosan-pectin gel beads (CPBs) were synthesized via a facile and green method and applied to remove heavy metals from aqueous solution. The structural characteristics of CPBs were investigated by SEM and FTIR, the mechanical strength of CPBs was measured by Texture Analyzer and the stability of CPBs was evaluated in acidic solution. To study the adsorption characteristics, the effect of pH, contact time, initial heavy metals concentration, temperature, adsorption mechanism and regeneration were systematically investigated. The adsorption kinetics fitted well pseudo-second-order model, and the adsorption isotherms were well described by Langmuir model. The maximum adsorption capacities of Cu(II), Cd(II), Hg(II) and Pb(II) were 169.4, 177.6, 208.5 and 266.5 mg/g, respectively. The adsorption-desorption experiments revealed that the CPBs exhibited a great reusability. Thus, the synthesized CPBs in this study had the potential to be utilized as an environment-friendly and green adsorbent for the removal of heavy metals.
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JOURNAL OF HAZARDOUS MATERIALS
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2021
·
IF 10.588
Zhike Wang,Ting-Ting Li,Hao-Kai Peng,Hai-Tao Ren,Ching-Wen Lou,Jia-Horng Lin
Hydrogels have extensively studied as adsorbents, raw materials for the preparation of adsorbent hydrogels have low strength, while high strength hydrogels have weak adsorption capacity. In this study, PVA hydrogel was crosslinked via trihydroxy melamine and epichlorohydrin, and β-cyclodextrin with strong adsorption capacity was added to remove the heavy metal ions . Results showed that the addition of trihydroxy melamine with 8%, the compressive strength of the hydrogel was increased by approximately 20%. The Langmuir isotherm model showed that the adsorption capacity of the hydrogel for Pb(II) and Ni(II) reached 505.9 mg/g and 286.7 mg/g, respectively, and the efficiency of removing the low-concentration heavy metal ions in water more than 99%. The hydrogel is low cost, and maintained highly removal efficiency under low pH. The removal efficiency of the hydrogel remained above 90% after five repeated adsorption-desorption experiments. The hydrogels have a potential to be used in wastewater treatment as adsorbents.
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JOURNAL OF MOLECULAR LIQUIDS
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2020
·
IF 5.065
Xiang Meng,Rui Hu
Nitrogen/phosphorus enriched biochars with enhanced porosity were prepared through a one-step pyrolysis of bamboo sawdust activated by guanidine phosphate (GP). The thermal decomposition of GP released alkaline gas and hydrogen proton to create more micropores in biochar matrix which were extended to be mesopores further. Nitrogenous/phosphorous moieties of GP were introduced into biochars efficiently via cross-linking with the carbon skeleton. GP-activated biochar pyrolyzed at 450 °C exhibited enriched surface functional groups (11.3 at.% for N, 4.1 at.% for P), resulting in high sorption capacities for aquatic Pb(II) (166.2 mg/g), Cu(II) (81.7 mg/g), and Cd(II) (60.3 mg/g). Pb(II) was passivated fast with the formation of minerals including Pb 5 (PO 4 ) 3 OH and Pb 5 (PO 4 ) 3 Cl. Cu(II) was strongly coordinated with the N-containing species especially pyridinic N. Cd(II) was also captured efficiently due to the chemical complexation, cation exchange and cation-π bonds. GP-activated biochars could be well-recycling used to capture these heavy metals. Regarding these, the activation of biomass residuals could be an efficient approach to functionalize the surface of biochars with enhanced porosity, which is great benefiting for the immobilization of heavy metals from contaminated water.
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SCIENCE OF THE TOTAL ENVIRONMENT
·
2020
·
IF 6.551
Ting-Ting Li,Zhike Wang,Hai-Tao Ren,Hao-Kai Peng,Xiao Zhang,Qian Jiang,Ching-Wen Lou,Jia-Horng Lin
This study reports a novel adsorbent structure and shows the satisfactory removal performance of Pb(II) and Ni(II). The fabric structure increases the strength of the hydrogel. The hydrogel plays a major role in the composite structure as a matrix, while the fabric bears the applied load and protects the structure from mechanical damage. The double-network composite hydrogel is reinforced by plasma grafted polylactic acid melt-blown non-woven fabric and polyethylene glycol dimaleate, and its compressive strength reaches 40.6 kPa at 60% strain. The interface substantially improves the compression strength by 42.9%. Through the adsorption isotherm model, the adsorption capacity of the hydrogel for Pb(II) and Ni(II) reaches 233.12 and 165.06 mg/g, respectively, and the removal rate of heavy metal ions in water at low concentrations exceeds 95%, showing the excellent removal rate of heavy metals. Even after the fifth cycle, the removal efficiency barely declines, indicating the feasibility of repeatedly use. Cost analysis reveals that the adsorbent is relatively low cost, solving the problems of difficult recovery, low strength, and easy damage of hydrogel adsorbents, and promoting the industrial application of hydrogels as adsorbents.
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Biomass Conversion and Biorefinery
·
2021
·Vol. 13
·期 9
·8277-8286
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IF 4.987
Wang Dongmei,Luo Weiye,Zhu Jingyi,Wang Tengfei,Gong Zhengjun,Fan Meikun
In this study, a novel alkali-modified biochar prepared from ginkgo leaves was produced by simply one-step pyrolysis and was investigated as an adsorbent for the removal of Pb, Cd, and Cu from aqueous solutions. After modified by alkali, ginkgo leaves biochar exhibited abundant surface functional groups and large porosity, resulting in high adsorption capacities for Pb (589.32 mg·g −1 ), Cd (563.55 mg·g −1 ), and Cu (81.7 mg·g −1 ). Simulation results showed that pseudo-second-order model and Langmuir model were better fitted to analyze the heavy metals adsorption process by alkali-BC, indicating that multilayer adsorption was the main reason for heavy metals removal. Besides, effect of pH and coexisting cations on adsorption of Pb, Cd, and Cu by alkali-BC was studied. Moreover, competitive adsorption of the three heavy metal ions by alkali-BC in binary system was also explored. Finally, the removal mechanism of Pb, Cd, and Cu in aqueous solution was analyzed and summarized. Due to the good performance in a wider pH range and high absorption capacity, alkali-BC would be an efficient adsorbent for heavy metals in real environmental samples.
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JOURNAL OF MOLECULAR LIQUIDS
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2021
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IF 6.165
Jiahao Li,Shiyao Li,Jiaao Chen,Rong Cheng,Fangyuan Chen,Xuli Li,Xuemei Zhang,Tianyu Zeng,Haobo Hou
Many Industrial effluents contain high concentrations of Cd(II) and Pb(II), which are serious problems for causing threat to human health. Adsorption has drawn considerable attention owing to its high efficiency and easy operation. In this paper, nanoscale nitrogen-doped aerogel microspheres (NCA) was synthesised through polymerization of phenolic resin and melamine in an emulsion suspension system. Factors influencing the adsorption properties of NCA and carbon aerogels microspheres (CA) toward Cd(II) and Pb(II) ions were studied, namely, pH, adsorbent content, initial Cd(II) and Pb(II) concentrations, and contact time. Furthermore, three models isotherm including Langmuir, Freundlich, and Sipss and three kinetic models were used in interpreting the adsorption process. NCA exhibited an excellent adsorption property and maximum removal capacity of 935.56 mg·g −1 for Pb(II) and 282.07 mg·g −1 for Cd(II). Results from XPS analysis implied that the amount of Pb absorbed by NCA was higher than that of CA mainly because of the complexing effect of nitrogen-containing functional groups on Pb(II). Furthermore, density functional theory (DFT) calculations confirm that N doping is beneficial to Pb(II) adsorption. These results suggested that NCA can be used as an adsorbent for the removal of Cd(II) and Pb(II) from industrial effluents.
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JOURNAL OF HAZARDOUS MATERIALS
·
2021
·
IF 10.588
Ruomeng Zhu,Pengling Zhang,Xinxin Zhang,Mei Yang,Ruiqi Zhao,Wei Liu,Zhongyue Li
A key matter in heavy metal removal technology is to develop the adsorbents with efficient adsorption sites. In this study, an oxygen-rich covalent organic framework (JUC-505) was functionalized by carboxyl (−COOH) groups to form synergetic effects aiming for the removal of Cd(II) and Pb(II) ions. JUC-505-COOH shows a high Cd(II) uptake of 504 mg⋅g −1 surpassing most of the reported porous adsorbents. Meanwhile, the kinetics study shows a rapid adsorption process at a high initial concentration (100 mg⋅L −1 ), and the equilibrium can be reached within 5 min. We investigated the adsorption mechanism in-depth by density functional theory calculations, proving the synergistic effects of surface complexation and hydrogen-bond, which are from the post-modified −COOH groups and the in-situ oxygen atoms of JUC-505, respectively. Moreover, under the interference of common ions in natural water, the removal efficiency of Cd(II) is almost insusceptible, which sheds lights on the potential for the application in the natural water purification . In addition, the Pb(II) uptake (559 mg⋅g −1 ) and the adsorption kinetics also surpass most of the reported porous adsorbents.
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ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2019
·Vol. 26
·期 11
·11126-11139
·
IF 2.914
Li Zhenyuan,Pan Zhidong,Wang Yanmin
A raw illite-smectite mixed-layered clay (RI/S) was ground for preparing nano-sized I/S clay (NI/S) and subsequently amino-functionalized via grafting of 3-aminopropyltrithoxysilane (APTES) (NH 2 -RI/S and NH 2 -NI/S, respectively). The samples were characterized by particle size analysis, specific surface area measurement, X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and 29 Si nuclear magnetic resonance ( 29 Si NMR). Compared to RI/S, NI/S has a narrow particle size distribution and appears in a platelet-like morphology due to the disintegration/exfoliation of RI/S after grinding. Based on the 29 Si NMR spectra, the appearances of tri-silicate units indicate the chemically grafting of APTES molecules on NH 2 -RI/S and NH 2 -NI/S, respectively. NH 2 -NI/S can adsorb greater amounts of Pb(II) cations and Cr(VI) anions rather than NH 2 -RI/S since NH 2 -NI/S grafts more amounts of amine groups (-NH 2 ). The isotherm data for adsorption of Pb(II) cations and Cr(VI) anions can be described by the Langmuir model at different temperatures (i.e., 10 °C, 30 °C, and 50 °C), respectively. The maximum adsorption amounts of Pb(II) cations and Cr(VI) anions onto NH 2 -NI/S calculated by the Langmuir isotherm model are 131.23 mg/g and 36.91 mg/g at 50 °C, respectively. The adsorptions of Pb(II) cations and Cr(VI) anions onto NH 2 -NI/S involve in the surface complexation of NI/S and amine groups.
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SENSORS AND ACTUATORS B-CHEMICAL
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2018
·
IF 5.667
Yuanyuan Lu,Xinqiang Liang,Jianming Xu,Ziyi Zhao,Guangming Tian
CuZrO 3 nanocomposites were prepared by chemical precipitation and oxidation at a high temperature (700 °C). The structural features of the fabricated CuZrO 3 nanocomposites (CuZrO 3 NCs) were elucidated by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The results presented herein show that these nanocomposites formed a nanograde needle structure with high crystallinity. By mixing with graphene (Gr), a CuZrO 3 -Gr composite modified glassy carbon electrode (CuZrO 3 -Gr/GCE) was successfully constructed for the simultaneous electrochemical detection of Pb(II) and Cd(II) in a acetate (NaAc-HAc) buffer solution (pH 4.6) via square wave anodic stripping voltammetry (SWASV). Due to the synergetic effect of the CuZrO 3 nanoparticles and graphene, the CuZrO 3 -Gr/GCE showed excellent electrical conductivity and mechanical stability in the presence of Pb(II) and Cd(II) ions. The limits of detection were 0.1 μg L −1 for Pb(II) and 0.5 μg L −1 for Cd(II). Application of this method for the co-detection of two ions in soil samples is expected to obtain useful results and possess significant advantages over tradition detection methods.
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CHEMOSPHERE
·
2018
·
IF 4.427
Guanghui Wang,Wenzhe Fan,Qin Li,Nansheng Deng
In this work, aspartic acid-β-cyclodextrin (ACD) was synthesized by the reaction of β-cyclodextrin with aspartic acid and epichlorohydrin, and graphene oxide-TiO 2 (GO-TiO 2 ) composite catalyst was prepared by a hydrothermal method. The complexation of ACD with New Coccine (NC) and Pb 2+ was characterized with FT-IR and XPS, respectively, the results show that ACD can simultaneously complex NC and Pb 2+ . XRD analysis and SEM images of GO-TiO 2 show that TiO 2 platelets are well distributed on both sides of the graphene oxide sheets, and display a similar XRD pattern to the pure TiO 2 nanoparticles with the typical diffraction peak of anatase phase. The effects of ACD on the photocatalytic degradation of NC and photocatalytic reduction of Pb 2+ were investigated in the single pollution system, and the synergistic effects on the simultaneous photocatalytic NC degradation and Pb 2+ reduction in the presence of ACD were also evaluated. The results showed that the presence of ACD was favorable to the acceleration of photocatalytic oxidation of NC and photocatalytic reduction of Pb 2+ in the single pollution system, and the photocatalytic reaction rate constants of NC and Pb 2+ in the presence of ACD increased 58% and 42%, respectively. For the combined pollution system, the synergistic effects on the simultaneous conversion of NC and Pb 2+ in aqueous solutions were also further enhanced. ACD enhanced photocatalytic activity was attributed to the improvement of the electron transfer and mass transfer at the GO-TiO 2 interface.
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CHEMOSPHERE
·
2018
·
IF 4.427
Bo Chen,Sijiang Chen,Huinan Zhao,Yang Liu,Fengxia Long,Xuejun Pan
Ascribing to their significant differences in physicochemical properties , it is extremely challenging to treat complex wastewater containing more than one class of pollutants via one-step treatment. Here, we focused on disposal of complex wastewater bearing organic dye and heavy metal by using adsorptive method. Thus, by combining the advantages of polyethyleneimine (PEI), β-cyclodextrin (β-CD) as well as Fe 3 O 4 magnetic nanoparticles , a versatile β-CD and PEI bi-functionalized magnetic nanoadsorbent (Fe 3 O 4 -PEI/β-CD) with spatially separated sorption sites was successfully constructed for simultaneous capture of methyl orange (MO) and Pb(II) in complex wastewater. In this setting, β-CD cavities and positively charged N-containing groups of PEI were mainly responsible for removal of MO via host-guest inclusion and electrostatic attraction, respectively, and oxygen-bearing groups on the edge of β-CD as well as the free amino moieties in PEI acted as the active sites for Pb(II) uptake. In their individual mono-pollutant system, the adsorption processes can be better described via applying pseudo-second-order kinetic and Langmuir isotherm models. Interestingly, presence of MO in Pb(II)-MO binary system significantly promoted the uptake of Pb(II). But the coexisting Pb(II) had almost no effects on MO uptake. Such results demonstrated that both MO and Pb(II) could be simultaneously and synergistically removed by Fe 3 O 4 -PEI/β-CD through multiple mechanisms (such as electrostatic attraction, host-guest inclusion, chelating, etc.). Particularly, the excellent regeneration and stability make Fe 3 O 4 -PEI/β-CD an ideal integrative adsorbent for purification of actual wastewater contaminated by MO and Pb(II). Thus, this study provides some insights into designing a well-performed and easily recyclable adsorbent for simultaneous and synergetic capture of both organic and inorganic contaminants in complex wastewater.
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ENVIRONMENTAL POLLUTION
·
2016
·
IF 4.839
Xia Jia,Yonghua Zhao,Tuo Liu,Shuping Huang,Yafei Chang
Glomalin-related soil protein (GRSP), which contains glycoproteins produced by arbuscular mycorrhizal fungi (AMF), as well as non-mycorrhizal-related heat-stable proteins, lipids, and humic materials, is generally categorized into two fractions: easily extractable GRSP (EE-GRSP) and total GRSP (T-GRSP). GRSP plays an important role in soil carbon (C) sequestration and can stabilize heavy metals such as lead (Pb), cadmium (Cd), and manganese (Mn). Soil contamination by heavy metals is occurring in conjunction with rising atmospheric CO 2 in natural ecosystems due to human activities. However, the response of GRSP to elevated CO 2 combined with heavy metal contamination has not been widely reported. Here, we investigated the response of GRSP to elevated CO 2 in the rhizosphere of Robinia pseudoacacia L. seedlings in Pb- and Cd-contaminated soils. Elevated CO 2 (700 μmol mol −1 ) significantly increased T- and EE- GRSP concentrations in soils contaminated with Cd, Pb or Cd + Pb. GRSP contributed more carbon to the rhizosphere soil organic carbon pool under elevated CO 2 + heavy metals than under ambient CO 2 . The amount of Cd and Pb bound to GRSP was significantly higher under elevated (compared to ambient) CO 2 ; and elevated CO 2 increased the ratio of GRSP-bound Cd and Pb to total Cd and Pb. However, available Cd and Pb in rhizosphere soil under increased elevated CO 2 compared to ambient CO 2 . The combination of both metals and elevated CO 2 led to a significant increase in available Pb in rhizosphere soil compared to the Pb treatment alone. In conclusion, increased GRSP produced under elevated CO 2 could contribute to sequestration of soil pollutants by adsorption of Cd and Pb.
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