Journal of Oleo Science
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2020
·
IF 1.304
Maomao Kou,Siting Feng,Nanjing Zhong
In this study, Lecitase® Ultra (LU) was immobilized onto the parent and the amino-functionalized SBA-15. The immobilization conditions were studied and the activity of the parent SBA-15 supported LU (SBA-15-LU) was found to be at 2177.78 ± 101.84 U/g. After 3-aminopropyl and n-(2-aminoethyl)-3-aminopropyl groups functionalization, enzymatic activity was increased to 3555.56 ± 200.21 and 3444.44 ± 346.41 U/g respectively. The immobilized LU samples were then used to catalyze glycerolysis. The possibility for diacylglycerols (DAG) and monoacylglycerols (MAG) production was evaluated and it was found only suitable for DAG production. In addition, the glycerolysis activity of the immobilized LU was impaired by the tert-pentanol and solvent-free was found suitable. Similar DAG content over 50 wt% could be obtained from glycerolysis by the three immobilized LU samples. The reusability in glycerolysis was evaluated, and 9.79 % of the initial glycerolysis activity was remained from the SBA-15-LU after 5 cycles of reuse. Encouragingly, after 3-aminopropyl and n-(2-aminoethyl)-3-aminopropyl groups functionalization, 62.93 and 83.91% of their initial activity was respectively remained after 5 cycles of reuse.
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高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
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2020
·
IF 2.627
Xiao Liang,Qing Li,Zhiyuan Shi,Shaowei Bai,Quanshun Li
Enzyme immobilization has been accepted as an efficient technique for improving the stability and recyclability of enzymes. Herein, biomimetic mineralization strategy was employed to achieve the immobilization of urease in a type of metal–organic frameworks (zeolite imidazolate framework-8, ZIF-8), and the immobilized enzyme urease@ZIF-8 was systematically evaluated for its structure, activity, stability and recyclability, using the hydrolysis of urea as a model. The entrapment of urease was found to be realized in a synchronous manner with the formation of ZIF-8 crystal. The loading of urease in ZIF-8 was measured to be ca. 10.6% through the bicinchoninic acid (BCA) protein assay. The encapsulated urease could efficiently maintain its native conformation, which endowed the immobilized urease with excellent activity and stability, even in harsh conditions ( e.g. , in the presence of trypsin, acidic or alkali conditions, or at high temperature). Further, urease@ZIF-8 exhibited good recyclability during the degradation of urea, in which it could keep 58.86% of initial activity after being used for 5 cycles. Thus, biomimetic mineralization could be potentially utilized as a promising method to prepare immobilized ureases with superior activity, stability and recyclability, thereby facilitating the construction of efficient catalysts for industrial biocatalysis and biosensing.
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CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Juanjuan Wan,Lijuan Zhang,Bo Yang,Boyu Jia,Jiakuan Yang,Xintai Su
Enzymes have important advantages in sludge dewatering , but their catalytic performance is limited by their poor activity and stability. To address this issue, we develop a series of immobilized enzymes (immobilized acid protease, IE 1; immobilized pectinase, IE 2; immobilized laccase, IE 3) prepared by the electrostatic interaction between the Fe 3 O 4 @SiO 2 -NH 2 as immobilized carrier and the free enzyme, and used for sludge dewatering. As-obtained immobilized enzymes endowed high efficiency and stable sludge dewatering performance in a wide pH range, and had the best dewatering performance when the pH was 5. Specifically, the specific resistance filtration (SRF) performance of the immobilized enzyme at pH 5 was better than that of the control group, and the order was FE 3, 3.84 × 10 13 m kg −1 > FE 1, 2.52 × 10 13 m kg −1 > CL 1, 2.16 × 10 13 m kg −1 > CL 2, 1.34 × 10 13 m kg −1 > FE 2, 2.06 × 10 13 m kg −1 > IE 2, 0.89 × 10 13 m kg −1 > IE 1, 0.82 × 10 13 m kg −1 > IE 3, 0.73 × 10 13 m kg −1 . Such improvement is attributed to two respects: Firstly, the immobilized enzyme has good activity, stability, and abundant functional groups on the surface, which is conducive to the attachment and continuous decomposition of organic matter. Secondly, the solid immobilized carrier can construct the skeleton structure in situ and effectively promote the release of water in sludge. This study provides a feasible way for the practical application of biological enzyme in sludge dewatering.
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JOURNAL OF HAZARDOUS MATERIALS
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2021
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IF 10.588
Yiqing Guo,Xiaoqin Li,Li Liang,Zhang Lin,Xintai Su,Wenchao Zhang
Sulfidated nanoscale zero-valent iron (S-nZVI) has shown excellent removal capacity for the removal of cadmium (Cd) in aqueous phase. Herein, the effectiveness and the mechanism of S-nZVI for the remediation of Cd contaminated soil were investigated for the first time. The results of sequential extraction procedures (SEP) showed that the exchangeable (EX) Cd was decreased by over 97.6% at the optimal dosage of 5 g kg -1 S-nZVI during 30 d incubation and converted to less available Cd such as iron-manganese oxides-bound (OX) and organic matter-bound (OM) fractions. pH has negligible effect on the immobilization of Cd in soil, since OX fraction was stabilized in the range of 72–92% at initial soil pH range from 5.3 to 7.5. SEM-EDS analysis of the separated magnetic particles implied that Cd was successfully enriched on S-nZVI and the distribution of Cd was closely related to Fe, S, and O. CdO and CdS was confirmed as the key products for Cd immobilization in soil. Meanwhile, the S-nZVI was oxided to α-FeOOH, γ-FeOOH, and γ-Fe 2 O 3 . The existence of CdO was visibly related to the iron oxides , suggesting the synergetic immobilization effect by iron oxides. Overall, S-nZVI was promising for the remediation of Cd-contaminated soil.
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ANALYTICA CHIMICA ACTA
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2021
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IF 6.558
Weihang Wang,Chi Zhang,Jiaxin Guo,Gaiping Li,Baoxian Ye,Lina Zou
Here, we developed a homogeneous electrochemical biosensor for the sensitive determination of antibiotic by the CHA reaction and the consecutive adenine mediated probe fixation. The binding of target to the target recognition sequences in the triple-helix DNA can release the trigger. It can initiate the catalytic hairpin assembly (CHA) to generate lots of mimic targets, which were labeled with electroactive substance ferrocene (Fc). Because the generated mimic target has consecutive sequence of adenines (PolyA), they can be self-assembled on the AuNPs modified electrode and finally realize electrochemical detection . Under optimal conditions, this developed biosensor achieved a satisfactory limit of detection of 0.089 nM (S/N = 3) and a linear range from 0.1 nM to 100 nM for sensitive detection of oxytetracycline with good specificity. The whole process is carried out in homogeneous solution, not only realizes signal amplification, but also avoids the complex modification process of electrode surface. Compared with some reported electrochemical sensors , the method is easier to operate and has good precision.
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CHEMICAL ENGINEERING JOURNAL
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2019
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IF 8.355
Mengxia Wang,Yanling Li,Dongye Zhao,Li Zhuang,Guiqin Yang,Yanyan Gong
Mercury (Hg) is one of the most toxic heavy metals in soil and groundwater, and mercury methylation is the key step for invasion of Hg into the food chain. Iron sulfide nanoparticles stabilized by carboxymethyl cellulose (CMC-FeS) have demonstrated excellent sorption/immobilization for mercury in water and soil. However, information has been lacking pertaining to the effects of CMC-FeS on speciation and microbial methylation of Hg at part per billion (ppb) level in groundwater. This work studied Hg speciation in the presence of CMC-FeS and the inhibitive effect of CMC-FeS on the microbial methylation of Hg in groundwater. CMC-FeS (CMC-to-FeS molar ratio of 0.0004) offered unusually high Hg sorption capacity, fast sorption rate, and good selectivity for mercury. The maximum Langmuir sorption capacity of CMC-FeS reached 3358.28 mg/g, which was enhanced by 8.81% compared to non-stabilized FeS. X-ray powder diffraction (XRD), Fourier transform infrared (FTIR), and X-ray photoelectron spectroscopy (XPS) analyses suggested that mercury removal was attributed to surface complexation, ion exchange, and chemical precipitation, resulting in the formation of FeS-Hg complexes and mercury sulfide (HgS). Dissolved oxygen had negligible effect on mercury uptake. The simple nanoparticle treatment inhibited mercury methylation by up to 60.8% when tested with a model metal-reducing bacterium Geobacter sulfurreducens PCA. When aged for 6 months, the nanoparticles exhibited excellent physical stability and high mercury capacity, and the immobilized mercury did not show any leaching. The present study provides direct evidence that immobilization of Hg by CMC-FeS remarkably inhibits microbial methylation of Hg, and thus mitigates toxic effects of mercury in water on human and the environmental health.
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CHEMICAL ENGINEERING JOURNAL
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2019
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IF 8.355
Hanlin Ding,Xiaonuo Zhang,Hao Yang,Xuegang Luo,Xiaoyan Lin
In this paper, a facile immobilization method was applied to load alginate , ferric oxide and dopamine onto fungal mycelium to prepare a series of spherical composites as potential adsorbents for the separation and removal of thorium from aqueous solution. The structure and chemical properties of the as-prepared adsorbents were characterized in detail via scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM-EDX), Fourier transform infrared spectrometry (FT-IR), X-ray photoelectron spectroscopy (XPS), pH value at the point of zero charge (pH PZC ) and thermogravimetric (TG) analysis. Based on the adsorption studies, the magnetic gamma-ferric oxide (γ-Fe 2 O 3 ) and polydopamine (PDA) cofunctionalized fungal microspheres (FPFMs) exhibited excellent adsorption performance for thorium and could represent convenient agents for the removal and recovery of thorium. The equilibrium adsorption data for the FPFMs were well fitted by the Langmuir model, and a high maximum thorium adsorption capacity of 326.346 mg·g −1 was obtained. The thermodynamic parameter values (Δ H 0 > 0, Δ S 0 > 0, Δ G 0 < 0) demonstrated that the thorium adsorption process was feasible, endothermic and spontaneous in nature. This work indicated that FPFMs have great potential to be employed as effective adsorbents for practical industrial water pollution treatment . Importantly, the possible mechanism of thorium adsorption on the homogeneous surface of FPFMs represented a combination of chelation interactions, coordination and ion exchange.
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FOOD CONTROL
·
2019
·
IF 4.248
Na Li,Xiaoying Liu,Jihe Zhu,Bijing Zhou,Junxian Jing,Aibing Wang,Rui Xu,Zhou Wen,Xingbo Shi,Shiyin Guo
A simple and sensitive electrochemical biosensor for acrylamide (AA) detection based on hemoglobin (Hb) entrapped in ionic liquid-carbon paste was constructed. The Hb-carbon ionic liquid paste electrode (Hb/CILPE) was studied and characterized by scanning electron microscopy (SEM) and electrochemical method. The surface passivation of the Hb/CILPE could be achieved by the addition of acrylamide molecule, which caused the lower current response value owing to the adduct formed by acrylamide and Hb as a result of the reaction between the α-NH2 group and the N-terminal valine of Hb. The experimental conditions such as pH value of supporting electrolyte, pulse increment and concentrated time of AA was examined. Under the optimum conditions, the differential pulse voltammetry (DPV) responses of Hb/CILPE toward AA was evaluated in a good linear range from 1.0 × 10 −11 to 1.0 × 10 −5 M, with a detection limit of 5.0 × 10 −12 M at S/N = 3. This biosensor can be successfully applied to the determination of AA in a real sample without complex pretreatment. Compared with other electrochemical methods for detecting AA, the prepared electrochemical biosensor exhibited advantages of simple preparation, easy surface renewal, better reproducibility and satisfactory stability.
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Materials Science & Engineering C-Materials for Biological Applications
·
2020
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IF 5.88
Xinxin Chen,Xiang Wang,Siyu Wang,Xiuhang Zhang,Jiaao Yu,Ce Wang
There has been a recent increase in research interest regarding the development of wound dressings containing bioactive compounds capable of improving outcomes for complex healing needs. In the present study, we describe the generation of bromelain immobilized eletrospun poly(ε-caprolactone) (PCL) fibers (BrPDA-PCL fibers) using the dopamine-assisted co-deposition strategy. We wanted to combine the structural advantage of electrospun fiber and the activity of bromelain and PDA to develop functional wound dressings. We found that bromelain activity could be better stabilized when via its immobilization on electrospun fibers. The resultant BrPDA-PCL fibers exhibited promising properties including optimal mechanical stability, wettability, and rates of water vapor transmission. In addition, these BrPDA-PCL fibers were biocompatible, allowing for effective cellular adhesion and proliferation. The results of zone of inhibition testing further confirmed that these fibers achieved effective antibacterial activity against Escherichia coli and Staphylococcus aureus . When used in vivo, as compared with PCL fibers or control animals the BrPDA-PCL fibers enhanced wound healing rates while reducing associated inflammation. As such, these results indicate that these biocompatible BrPDA-PCL fibers exhibit desirable physicochemical properties making them ideal for use as a wound dressing to enhance the repair of full-thickness wounds to the skin.
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Nature Energy
·
2019
·Vol. 4
·期 5
·408-415
·
IF 54
Li Nengxu,Tao Shuxia,Chen Yihua,Niu Xiuxiu,Onwudinanti Chidozie K.,Hu Chen,Qiu Zhiwen,Xu Ziqi,Zheng Guanhaojie,Wang Ligang,Zhang Yu,Li Liang,Liu Huifen,Lun Yingzhuo,Hong Jiawang,Wang Xueyun,Liu Yuquan,Xie Haipeng,Gao Yongli,Bai Yang,Yang Shihe,Brocks Geert,Chen Qi,Zhou Huanping
Defects play an important role in the degradation processes of hybrid halide perovskite absorbers, impeding their application for solar cells. Among all defects, halide anion and organic cation vacancies are ubiquitous, promoting ion diffusion and leading to thin-film decomposition at surfaces and grain boundaries. Here, we employ fluoride to simultaneously passivate both anion and cation vacancies, by taking advantage of the extremely high electronegativity of fluoride. We obtain a power conversion efficiency of 21.46% (and a certified 21.3%-efficient cell) in a device based on the caesium, methylammonium (MA) and formamidinium (FA) triple-cation perovskite (Cs 0.05 FA 0.54 MA 0.41 )Pb(I 0.98 Br 0.02 ) 3 treated with sodium fluoride. The device retains 90% of its original power conversion efficiency after 1,000 h of operation at the maximum power point. With the help of first-principles density functional theory calculations, we argue that the fluoride ions suppress the formation of halide anion and organic cation vacancies, through a unique strengthening of the chemical bonds with the surrounding lead and organic cations.
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JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY
·
2018
·Vol. 317
·期 3
·1419-1428
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IF 1.181
Ouyang Jinbo,Wang Yun,Li Tianqi,Zhou Limin,Liu Zhirong
The carboxyl-modified multiwalled carbon nanotubes were immobilized in chitosan-based composite membranes (CS-CNTs) which were used as efficient sorbents for U(VI) sorption. The incorporation of CNTs in the CS-CNTs membranes improves their mechanical strength as well as U(VI) sorption performance. XPS analysis indicates that both amine and carboxyl groups are responsible for the complexation of U(VI). The sorption kinetics followed the pseudo-second order equation, whereas the sorption isotherms fitted well with Langmuir model ( q m = 126.7 mg g −1 at 298 K). Moreover, the U(VI)-loaded CS-CNT8 can be effectively desorbed by 0.2 M acidified EDTA and reused.
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MACROMOLECULAR RESEARCH
·
2018
·Vol. 26
·期 13
·1241-1250
·
IF 1.767
Shen Xiang,Liu Peng,Xu Jiao,Liu Teng,Liu Jianjun,Shen Xianfu,Xia Shubiao,Wang Fan
Membrane technology has been accepted as a very effective approach to purify oily wastewater. However, the serious membrane fouling induced by the adsorption of oily foulants significantly hinders the development of membrane technology in treating oily wastewater. To improve the anti-fouling property and oil/water separation efficiency of membrane, this work reports on the covalent immobilization of short-chain arginine (Arg) molecules onto polyacrylonitrile/polyacrylonitrile- co -poly(glycidyl methacrylate) (PAN/PAN- co -PGMA) blend membrane surface via a ring-opening reaction between epoxy groups and amine groups. It was found that the covalent immobilization of Arg molecules effectively increased the surface hydrophilicity of the membrane, resulting in a significant decrease of the interaction force between the foulants and the membrane surface. This typical characteristic was revealed by the pure water contact angle and the force-extension curve measurements. The Arg-immobilized membranes exhibited much higher separation efficiency against oil/water emulsions than the pristine PAN and PAN/PAN- co -PGMA membranes. Especially when the grafting amount of Arg was 157.3 μg/cm 2 , the oil rejection ratio of an Arg-immobilized membrane was as high as 99.2%. In addition, the flux recovery ratio of the membrane still reached 88.8%, even after two cycle filtrations of pure water and oil/water emulsion. These results indicated that the Arg-immobilized membrane may have practical applications for oil/water emulsion separation.
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