ENVIRONMENTAL POLLUTION
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2020
·
IF 6.793
Zhiyan Huang,Lu Jiang,Pingxiao Wu,Zhi Dang,Nengwu Zhu,Zehua Liu,Hanjin Luo
For further understanding leaching characteristics of heavy metals in tailings and better immobilization on heavy metals against acid rain, batch experiments were conducted. The leaching results of Cu(II), Zn(II), Cd(II) and Mn(II) can be well fit by second-order kinetics equation , and Pb(II) can be well fit by two-constant equation. The leaching intensity of heavy metals in tailings was ranged as: Mn(II)> Cu(II)> Cd(II)> Zn(II)> Pb(II). Triethylenetetramine functioned montmorillonite (TETA-Mt) was successfully synthesized and can obtain simultaneous immobilization effect compared with Mt and TETA, and immobilization rates on Cu(II), Cd(II), Mn(II) and Zn(II) can reach above 90%, the immobilization rate on Pb(II) can reach more than 75%. The mechanisms for efficient immobilization of heavy metals on TETA-Mt included buffering and adsorption abilities. The mechanism for TETA-Mt adsorption of heavy metals included physical absorption, chelation and chemical sedimentation. The results showed that TETA-Mt can be applied to effective immobilization of heavy metals in tailings and efficient remediation of acid mine drainage (AMD) in acid rain area.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2020
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IF 5.162
Wei Huang,Shuai Pan,You Li,Lulu Yu,Ruijiang Liu
In this work, magnetic Fe 2 O 3 /Fe 3 O 4 nanocomposites were prepared via a novel rapid combustion process. The silica was precipitated on the surface of Fe 2 O 3 /Fe 3 O 4 nanocomposites. The silica-coated magnetic nanocomposites were cross-linked with glutaraldehyde, on which cellulase was covalently immobilized. The morphology, composition, and property of the prepared nanomaterials were characterized by the scanning electron microscopy (SEM), the energy dispersive spectrometry (EDS), the X-ray diffraction (XRD), the vibrating sample magnetometer (VSM), and the Fourier transform infrared (FTIR) spectroscopy. The immobilization conditions were optimized by varying operating parameters and determined to be 0.05 mL of 0.5% cellulase solution for 2 h. The catalytic stabilities of the immobilized cellulase were evaluated. The results showed that the immobilized cellulases performed higher apparent activity at pH 4.5 and exhibited good thermal stability compared with their free counterparts. The Michaelis-Menten equation showed that K m and V max of free cellulase were 3.46 mol·L −1 and 0.53 mol·min −1 , respectively. The immobilized cellulase had higher K m and V max (18.99 mol·L −1 and 0.59 mol·min −1 ). The retained activity of the immobilized cellulase maintained over 71% of the initial activity after being used for five cycles.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2019
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IF 3.131
Hao Yang,Hanlin Ding,Xiaonuo Zhang,Xuegang Luo,Yu Zhang
In this study, a new surface-modified biobased composite was obtained by modifying the surface of fungal mycelium microspheres (FHMs) with polydopamine (PDA). A. niger mycelium/PDA microspheres (AM/PDA microspheres) were used as a highly efficient adsorbent for the removal of U(VI) ions. This study examined the effects of the initial pH, ionic strength, and electrolyte ions on the U(VI) adsorption capacity of the AM/PDA microspheres. The results confirmed that U(VI) was successfully adsorbed on the AM/PDA microspheres. We compared their adsorption capacity with that of other adsorbents, and the adsorption rate and adsorption capacity of the AM/PDA microspheres were found to be higher than those of the other adsorbents. Equilibrium was achieved after 300 min, and the AM/PDA microspheres had a maximum adsorption capacity of 250.70 mg/g. We aimed not only to investigate the factors that affect the adsorption process but also to provide a new mycelial-based composite adsorbent for U(VI)-contaminated water.
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JOURNAL OF ENVIRONMENTAL MANAGEMENT
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2019
·
IF 4.865
Yasir Hamid,Lin Tang,Bilal Hussain,Muhammad Usman,Muhammad Laeeq ur Rehman Hashmi,Muhammad Bilal Khan,Xiaoe Yang,Zhenli He
The present study evaluated the efficiency of pre-selected composite amendments (CA-1: biochar-lime-sepiolite-zeolite and CA-2: manure-lime-sepiolite) for immobilization and sorption of Cd and Pb in field and batch sorption experiments. The field experiment was performed in a co-contaminated clay purple soil (stagnic anthrosols). Along with a control experiment (T1), CA-1 and CA-2 were tested at different rates including 750, 1500, 3000 and 6000 kg ha −1 by growing wheat as the test crop. The obtained results revealed that the highest dose of both composites (T5: 6000 kg ha −1 and T9: 6000 kg ha −1 ) increased the soil pH to 6.85 and 6.81, respectively as compared to the control (5.63). DTPA-extractable Cd and Pb contents decreased with composite treatments (T7 and T4) at harvest stage samples. Metal fractionation depicted that application of amendments decreased the exchangeable fraction at harvesting stage. Application of CA-2 and CA-1 (3000 kg ha −1 ) significantly increased the plant biomass (by 28% and 24%, respectively) and grain yield (by 26% and 22%, respectively) of wheat. Furthermore, batch sorption experiment results revealed that Langmuir adsorption model better fitted the sorption results with R 2 values ranging between 0.99 and 0.91 for Cd and Pb, respectively. CA-1 and CA-2 exhibited the maximum adsorption capacity for Cd with no significant difference among treatments but Pb adsorption capacity was highest in CA-1 followed by CA-2 and control. The results of our experiments revealed that the application of organics combined with inorganic materials enhanced Cd and Pb immobilization and sorption, consequently reducing metals availability in laboratory and field conditions. Moreover, for field trials, application of the composite amendments at 3000 kg ha −1 emerged as the suitable treatment for tested wheat-grown area.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2019
·
IF 3.375
Dewei Wan,Chaoren Yan,Qiuyu Zhang
Multifunctional magnetic polydopamine (PDA) nanospheres have become a research hotspot, especially in the field of biocatalysis, owing to their good biocompatibility and abundant functional groups. However, facile and rapid synthesis of hollow magnetic mesoporous PDA (HM-MPDA) with high saturation magnetization, large tailored pore size, excellent structural thermal stability, and controllable shell thickness is still a challenge. Herein, HM-MPDA nanospheres with ultrahigh magnetization (∼82.2 emu/g), ultra-large tunable pore sizes (11.53–49.53 nm), rigid pore structures (at 550 °C), and controllable shell thickness (23–178 nm) are synthesized based on a novel nanoemulsion co-assembly approach. Impressively, the hollow magnetic mesoporous PDA nanoflowers (HM-MPDA-NFs) are obtained by simply adjusting the amount of 1,3,5-trimethylbenzene and the P123/F127 weight ratios. Considering their unique properties, lipases were successfully immobilized on the pore walls of HM-MPDA-NFs, which were employed for the preparation of biodiesel. Under the optimum esterification conditions, the conversion of biodiesel can reach up to 87.9% and still exceed 71.3% after six times of recycling. More importantly, this study opens up a new way to fabricate hollow magnetic mesoporous nanocarriers, which can provide many applications in biocatalysis, dye adsorption, electrochemistry, and biosensing.
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Acta Biomaterialia
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2019
·
IF 6.638
Yiyuan Duan,Shan Yu,Peifang Xu,Xuemei Wang,Xue Feng,Zhengwei Mao,Changyou Gao
Capture of endothelial progenitor cells (EPCs) in situ has been considered as a promising strategy for the rapid endothelialization and long-term patency of artificial blood vessels and implant devices. In this study, a CD133 + EPC capture surface was fabricated by grafting CD133 antibody (a more specific EPC surface marker than CD34) and Arg-Glu-Asp-Val (REDV) peptideon the methacrylate-grafted hyaluronic acid (MA-HA) and heparin-hybridized (MA-HA&Heparin) resisting layer. Vascular endothelial growth factor (VEGF) was further conjugated to the immobilized heparin. This engineered surface showed good hemocompatibility and significantly higher ability of capturing CD133 + EPCs from human peripheral blood mononuclear cells (PBMCs) and obviously upregulated the expression of endothelial cell (EC) marker genes of EPCs such as VEGF receptor 2 (VEGFR2), CD31 , VE-cadherin, and von Willebrand factor (vWF), facilitating the differentiation of EPCs into ECs. The dramatically enhanced EPC proliferation on this surface was dependent on the integrin-VEGFR synergistic signaling, as ERK1/2 phosphorylation was only significantly enhanced on the REDV and VEGF co-immobilized surface. This study highlights a new surface coating strategy for blood-contact materials based on the specific EPC capturing and rapid endothelialization. Statement of Significance Capture of endothelial progenitor cells (EPCs) in situ is a promising strategy for the rapid endothelialization and long-term patency of artificial blood vessels and scaffolds. More specific capture of EPCs by targeting CD133 rather than CD34 can better reduce the risk of inflammation and restenosis. On the other hand, an appropriate microenvironment for EPC proliferation is equally important for endothelialization, which is rarely considered by the existing EPC capture strategies. In this study, the capture ratio of EPCs was significantly increased by simultaneously grafting CD133 antibody and VEGF on a MA-HA and heparin-hybridized antifouling layer. Further, proliferation of EPCs after capture was significantly promoted by grafting VEGF and REDV peptide through the integrin–VEGFR synergistic signaling. This study highlights a new strategy for the surface coating of blood-contact materials based on specific EPC capture and rapid endothelialization.
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ENGINEERING IN LIFE SCIENCES
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2019
·Vol. 19
·期 11
·815-824
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IF 1.936
Xin Li,Dawei Li,Pengfei Lv,Jinyan Hu,Quan Feng,Qufu Wei
In this study, 2-hydroxyethyl methacrylate (HEMA) was used as the monomers for surface grafting on electrospun PU/RC nanofiber membrane via atom transfer radical polymerization (ATRP) method, and the PU/RC-poly(HEMA) nanofiber membrane was investigated as a carrier for LAC. Free and immobilized LAC was characterized, and efficiency of bisphenol A (BPA) removal was determined. The results indicated that the PU/RC-poly(HEMA)-LAC showed relatively higher pH stability, temperature stability, and storage stability than free and PU/RC-LAC; moreover, more than 60% of the PU/RC-poly(HEMA)-LAC activity was retained after 10 cycles of ABTS treatment. Notably, the BPA removal efficiency of PU/RC-poly(HEMA)-LAC membrane generally ranged from 87.3 to 75.4% for the five cycles. Therefore, the PU/RC-poly(HEMA) nanofiber membrane has great potential as a carrier for the LAC immobilization for various industrial applications and bioremediation.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2018
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IF 2.829
Mingjuan Han,Ying Li,Zheng Gu,Huali Shi,Chong Chen,Qiang Wang,Hui Wan,Guofeng Guan
A novel functionalized MOF heterogeneous catalyst (MIL-101(Cr) @MBIAILs), 2-Mercaptobenzimidazole ILs with electron-rich SH groups immobilized onto the surface of the well-defined MIL-101(Cr) frameworks, was constructed and fabricated by the S Cr coordination bond on the basis of the facile post-synthetic modification strategy. The heterogeneous catalyst was measured by XRD , FTIR, SEM, TEM , TGA , EA and N 2 adsorption–desorption, and the catalytic behavior of the catalyst was assessed by the esterification about oleic acid and methanol as a model reaction. The results showed that MBIAILs have been successfully immobilized onto the surface of MIL-101(Cr) frameworks by S Cr coordinate bonds. More importantly, the conversion of oleic acid just decreased from 91.0% to 82.1% when the catalyst had been reused six times. This exhibited the prepared catalyst had superior catalytic behavior and excellent reusability.
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BIORESOURCE TECHNOLOGY
·
2018
·
IF 5.807
Qingtai Chen,Dong Liu,Chongchong Wu,Kaisheng Yao,Zhiheng Li,Nan Shi,Fushan Wen,Ian D. Gates
An activity-tunable biocatalyst for Nannochloropsis sp. cell-walls degradation was prepared by co-immobilization of cellulase and lysozyme on the surface of amino-functionalized magnetic nanoparticles (MNPs) employing glutaraldehyde. The competition between cellulase and lysozyme during immobilization was caused by the limited active sites of the MNPs. The maximum recovery of activities (cellulase: 78.9% and lysozyme: 69.6%) were achieved due to synergistic effects during dual-enzyme co-immobilization. The thermal stability in terms of half-life of the co-immobilized enzymes was three times higher than that in free form and had higher catalytic efficiency for hydrolysis of cell walls. Moreover, the co-immobilized enzymes showed greater thermal stability and wider pH tolerance than free enzymes under harsh conditions. Furthermore, the co-immobilized enzymes retained up to 60% of the residual activity after being recycled 6 times. This study provides a feasible approach for the industrialization of enzyme during cell-walls disruption and lipids extraction from Nannochloropsis sp.
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NEW JOURNAL OF CHEMISTRY
·
2018
·Vol. 43
·期 1
·146-153
·
IF 3.201
Haotian Zhu,Jing Du,Ying Lu,Fang Su,Yangguang Li
A new polyoxometalate (POM)-based organic–inorganic hybrid compound, {[(Zn(H2biim)2)3(P2W18O62)]·6H2O}n (1) (H2biim = 2,2′-biimidazole), has been hydrothermally synthesized and characterized by physico-chemical and spectroscopic methods. The structure of compound 1 exhibits a two-dimensional (2-D) network character, in which each Dawson-type polyoxoanion [P2W18O62]6− ({P2W18}) is connected with six [Zn(H2biim)2]2+ ({Zn(II)-H2biim}) complex fragments, while each {Zn(II)-H2biim} unit bridges two {P2W18} clusters, forming a 2-D network with a (6,3)-net topology. Compound 1 shows high enzyme-immobilizing capability for horseradish peroxidase (HRP). The maximum HRP load is 90.1 mg g−1 under optimal conditions. Furthermore, the immobilized enzyme (HRP/1) exhibits high catalytic activity and good stability, which can be applied to detect trace amounts of H2O2 in solution with a low detection limit of 3.11 × 10−3 mmol L−1.
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JOURNAL OF SOLID STATE ELECTROCHEMISTRY
·
2014
·Vol. 18
·期 12
·3463-3469
·
IF 2.234
Chen Ya,Huang Yihan,Guo Dongmei,Chen Cui,Wang Qinghong,Fu Yingzi
A sensitive electrochemical method was explored for chiral recognition of 3,4-dihydroxyphenylalanine (DOPA) enantiomers based on immobilization of β -cyclodextrin ( β -CD) onto the nanocomposite comprising multiwalled carbon nanotubes (MWCNTs) and ionic liquid (IL) 1-butyl-3-methylimidazolium hexafluorophosphate (BIMIMPF 6 ) modified glassy carbon electrode ( β -CD/MWCNTs-IL/GCE). The combination of ionic liquid and carbon nanotubes could create unique nanomaterials which facilitated the electron transfer. In addition, β -CD was brought in to act as the chiral selector for DOPA enantiomers recognition. The immobilization process of β -CD/MWCNTs-IL/GCE was monitored by cyclic voltammetry, electrochemical impedance spectroscopy, and scanning electron microscopy. The chiral interface ( β -CD/MWCNTs-IL/GCE) was employed to discriminate DOPA enantiomers via differential pulse voltammetry. The results indicated that the proposed sensor exhibited a stronger electrochemical response toward D-DOPA over the linear range from 4.0 × 10 −3 to 4.0 × 10 −9 mol L −1 and the detection limit was 1.2 × 10 −9 mol L −1 (S/N = 3). This work provided an available platform for enantioselective recognition of DOPA enantiomers based on the nanocomposite.
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JOURNAL OF MEMBRANE SCIENCE
·
2015
·
IF 5.056
Junhui Wu,Zhi Wang,Wentao Yan,Yao Wang,Jixiao Wang,Shichang Wang
A commercial polyamide reverse osmosis (RO) membrane was surface modified in a sequential two-step dip coating process for improvement of the hydrophilicity and fouling resistance. In the first step, an ultrathin metal-polyphenol precursor layer was deposited onto the membrane surface via the self-assembly of tannic acid (TA) and Fe(III) ions, and polyethylenimine (PEI) was added as a covalent cross-linker. In the second step, poly(N-vinylpyrrolidone) (PVP), a common hydrophilic polymer , was immobilized onto the metal-polyphenol precursor layer through the strong hydrogen bonding interactions between the lactam groups in PVP and the phenolic hydroxyl groups in the precursor layer. X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), transmission electron microscopy (TEM) and zeta potential measurements confirmed the successful immobilization of the precursor layer and PVP. Atomic force microscopy (AFM) test indicated a smoother surface of the modified membrane. Furthermore, the water flux of the modified membrane was only slightly decreased and the salt rejection was almost unchanged. More importantly, static contact angle measurement showed that the membrane surface hydrophilicity was significantly improved after the PVP immobilization (contact angle from 59.0±1.2° to 14.5±2.4°). Membrane fouling experiments were performed over three “filtration–rinsing” cycles using two proteins (lysozyme and bovine serum albumin) and one polysaccharide (sodium alginate) as model foulants. The results of the fouling experiments revealed that the fouling resistance of the reverse osmosis membrane was obviously improved by the surface immobilization of PVP. Besides, cross-flow filtration test under high hydrodynamic shear condition for 15 days indicated the excellent stability of the immobilized PVP. This work provided a new potential strategy for improving the fouling resistance of RO membranes.
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