Processes
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2018
·Vol. 6
·期 5
·54
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IF 1.279
Lei Chen,Cuiyun Liu,Yongjun Sun,Wenquan Sun,Yanhua Xu,Huaili Zheng
The ampholytic chitosan based flocculant carboxylated chitosan graft-(3-chloro-2-hydroxypropyl) trimethylammonium chloride-dimethyl diallyl ammonium chloride (CPCTS-g-P (CTA-DMDAAC)) was synthesized by photo polymerization using carboxylated chitosan (CPCTS), 3-chloro-2-chloropropyltrimethylammonium chloride (CTA) and dimethyldiallylammonium chloride (DMDAAC) as the cationic co-monomers. The effects of monomer concentration, the ratio of CPCTS and cationic monomers, cationic degree, initiator time, photoinitiator concentration, and pH value on the properties of CPCTS-g-P (CTA-DMDAAC) were studied. Themicrocystis aeruginosathat was cultured in laboratory was used for CPCTS-g-P (CTA-DMDAAC) flocculation tests. The effects of CPCTS-g-P (CTA-DMDAAC) dosage, pH value and G value on flocculation performance were investigated. The maximum removal rate of chlorophyll-a (Chl-a) and chemical oxygen demand (COD) that were obtained by CPCTS-g-P (CTA-DMDAAC) were 98.8% and 96.5% under the conditions of dosage 4 mg/L, pH 7 and G value 200 s−1, respectively. The flocculation experiments showed that chitosan-based flocculant CPCTS-g-P (CTA-DMDAAC) had better flocculation performance than commercially available flocculants cationic polyacrylamide (CPAM), Polyferric Sulfate (PFS), and polymeric aluminium (PAC).Keywords:chitosan-based flocculant;alga removal;graft copolymerization;photopolymerization;flocculation properties
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高影响因子
APPLIED MICROBIOLOGY AND BIOTECHNOLOGY
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2018
·Vol. 102
·期 4
·1749-1758
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IF 3.34
Pan Xin,Wang Li,Ye Jiajie,Qin Song,He Bingfang
Penicillin G acylase (PGA) was isolated from Providencia rettgeri PX04 (PrPGApx04) and utilized for the kinetically controlled synthesis of β-lactam antibiotics. Site-directed mutagenesis was performed to increase the process efficiency. Molecular docking was carried out to speculate the key mutant positions corresponding with synthetic activity, which resulted in the achievement of an efficient mutant, βF24G. It yielded higher conversions than the wild-type enzyme in the synthesis of amoxicillin (95 versus 17.2%) and cefadroxil (95.4 versus 43.2%). The reaction time for achieving the maximum conversion decreased from 14 to 16 h to 2–2.5 h. Furthermore, the secondary hydrolysis of produced antibiotics was hardly observed. Kinetic analysis showed that the ( k cat / K m ) AD value for the activated acyl donor D-hydroxyphenylglycine methyl ester (D-HPGME) increased up to 41 times. In contrast, the ( k cat / K m ) Ps values for the products amoxicillin and cefadroxil decreased 6.5 and 21 times, respectively. Consequently, the α value ( k cat / K m ) Ps /( k cat / K m ) AD , which reflected the relative hydrolytic specificity of PGA for produced antibiotics with respect to the activated acyl donor, were only 0.028 and 0.043, respectively. The extremely low hydrolytic activity for the products of the βF24G mutant enabled greater product accumulation to occur during synthesis, which made it a promising enzyme for industrial applications.
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PubMed
高影响因子
NEW JOURNAL OF CHEMISTRY
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2018
·Vol. 42
·期 21
·17644-17651
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IF 3.201
Shaobo Li,Tao Zhu,Lichun Dong,Mingdong Dong
Heteroatom doping has been demonstrated to be an effective way to tune the properties of nanomaterials including chemical reactivity and electronic and optical performance. In this study, rGO/g-C3N4 and boron doped rGO/g-C3N4 (B-rGO/g-C3N4) nanocomposites were fabricated via a rapid plasma treatment method, and their photocatalytic performance under visible light radiation was examined. The results showed that the photocatalytic efficiency of B-rGO/g-C3N4 for rhodamine B degradation can be 50% higher than that of rGO/g-C3N4 at an optimum rGO loading of 5 wt%. XPS and FTIR analyses indicated the enhanced C–O–C covalent bonding between rGO and g-C3N4 in B-rGO/g-C3N4, and the optical characterization demonstrated that it could further improve the separation of the photo-generated chargers and narrow the bandgap of the nanocomposite. This work provides an idea that boron doping could be an effective way to promote the chemical interaction between different components in composite materials, which is important in designing and developing new functional nanomaterials.
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SCIENCE OF THE TOTAL ENVIRONMENT
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2018
·
IF 4.61
Usman Farooq,Muhammad Danish,Shuguang Lyu,Mark L. Brusseau,Mengbin Gu,Waqas Qamar Zaman,Zhaofu Qiu,Qian Sui
The surface properties of nanocomposites are influenced by the existence of inorganic species that may affect its performance for specific catalytic applications. The impact of different ionic species on particular catalytic activity had not been investigated to date. In this study, the surface charge (zeta potential) of graphene-oxide-supported nano zero valent iron (G-nZVI) was tested in definitive cationic (Na + , K + , Ca 2+ and Mg 2+ ) and anionic (Br − , Cl − , NO 3 − , SO 4 2− , and HCO 3 − ) environments. The efficiency of G-nZVI catalyst was inspected by measuring the generation of reactive oxygen species (ROS) for the degradation of 1,1,1-trichloroethane (TCA) in sodium percarbonate (SPC) system. Tests conducted using probe compounds confirmed the generation of OH and O 2 − radicals in the system. In addition, the experiments performed using scavenging agents certified that O 2 − were primary radicals responsible for TCA removal, along with prominent contribution from OH radicals. The study confirmed that G-nZVI catalytic capability for TCA degradation is notably affected by various cationic species. The presence of Ni 2+ and Cu 2+ significantly enhanced (94%), whereas Na + and K + had minor effects on TCA removal. Overall, the results indicated that groundwater ionic composition may have low impact on the effectiveness of G-nZVI-catalyzed peroxide TCA treatment.
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PubMed
高影响因子
Catalysis Science & Technology
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2018
·Vol. 8
·期 11
·2853-2859
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IF 5.365
Ya-Nan Liu,Xiao Zhou,Cong-Cong Shen,Zhi-Wei Zhao,Yi-Fan Jiang,Liu-Bo Ma,Xiao-Xiang Fang,Zeb Akif,Tuck-Yun Cheag,An-Wu Xu
Herein, a polymeric graphitic carbon nitride (for simplicity, g-C3N4) photocatalyst has been identified as a promising material for hydrogen production from water due to its comparatively low cost and facile modification of its electronic structure. However, to date, how to speed up the transfer rate of photogenerated charges, especially hole transfer rate, still remains a formidable challenge. Herein, a novel system of g-C3N4/1,1′-ferrocenedicarboxylic acid (FcDA) composites was developed for efficient visible light-driven H2 evolution, in which the redox mediator FcDA served as hole-transport molecules and platinum (Pt) acted as an electron sink. The FcDA molecules are anchored onto g-C3N4 by hydrogen-bonding interactions between the carboxylic groups and amino groups as well as π–π interactions between aromatic FcDA and graphitic C3N4. The matched energy-levels between g-C3N4 and FcDA facilitate photogenerated hole transfer from the g-C3N4 valence band to FcDA that results in the formation of FcDA+ radicals, and thus, photoinduced electrons and holes are efficiently separated. Due to the additional charge separation pathway, enhanced hole transfer kinetics, and the extremely rapid intermolecular radical reactions, charge recombination is effectively suppressed; therefore, more electrons can be released for hydrogen production. Under optimal experimental conditions, the developed g-C3N4/FcDA composite with 4 wt% FcDA exhibits high water splitting activity with a H2 evolution rate of up to 77.91 μmol h−1, which is nearly 6 times that of bare g-C3N4 (13.18 μmol h−1). Moreover, the obtained g-C3N4/FcDA photocatalyst displays excellent stability, and there is no obvious decrease in the H2-production rate after five test cycles. Thus, we anticipate that our simple modification strategy will offer an avenue to merge the polymeric g-C3N4 photocatalyst with surface organometallic chemistry for high-efficiency solar-to-fuel conversion.
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高影响因子
APPLIED SURFACE SCIENCE
·
2019
·
IF 5.155
Xue-Chun Yang,Yun-Ling Yang,Shao-Lin Zhang,Yu-Feng Liu,Si-Jie Fu,Meng Zhu,Jian-Feng Hu,Zhi-Jun Zhang,Jing-Tai Zhao
A novel porous nitrogen doped carbon dots (NCDs)@g-C 3 N 4 composite was successfully synthesized by a facile hydrothermal approach. The surface area of NCDs@g-C 3 N 4 can reach up to 60.9 m 3 /g, and pores with diameter between 20–50 nm are the most widely distributed. The photocatalytic activity of NCDs@g-C 3 N 4 toward the degradation of Methylene blue (MB) under visible light irradiation was remarkably higher than that of g-C 3 N 4 and NCDs. The improved photocatalytic activity can be attributed to the fact that the addition of NCDs not only broadens the photo-response range, but also suppresses the photo-generated electrons and holes recombination of g-C 3 N 4 . Degradation rate of 2.0 wt% NCDs@g-C 3 N 4 is about twice than that of pristine g-C 3 N 4 at 60 min under the same conditions. In addition, at 120 min, MB was almost degraded completely by 2.0 wt% NCDs@g-C 3 N 4 with the degradation rate as high as 97.9%, while the pristine g-C 3 N 4 was only 69%. NCDs@g-C 3 N 4 can be used as a potential catalyst for organic contaminants degradation considering its high photo-response range and excellent photocatalytic activity. Moreover, NCDs, g-C 3 N 4 and NCDs@g-C 3 N 4 also can be used as fluorescent inks for anti-counterfeiting.
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高影响因子
JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY
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2018
·Vol. 94
·期 2
·398-408
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IF 2.587
Chen Li,Lei Wang,Xudong Wang,Cuicui Li,Qibin Xu,Guangyuan Li
BACKGROUND Proton-exchange membrane (PEM) has a significant effect on the performance and overall cost of microbial fuel cells (MFCs). In this study, a novel composite PEM is fabricated by compositing sulfonated graphene oxide (SGO) with the Poly(vinylidene fluoride)-g-Poly(styrene sulfonic acid) (PVDF-g-PSSA) copolymer. The performance of MFCs with these newly prepared composite PEMs as separators was evaluated. A Quartz crystal microbalance with dissipation (QCM-D) combined with membrane-coated sensor crystals was used to investigate the biofouling mechanism of PEMs in MFCs at a micro-perspective. RESULTS The successful sulfonation of GO was confirmed by Fourier transform infrared spectrometry and X-ray photoelectron spectroscopy. When the SGO loading was 1.0 wt%, the SGO/PVDF-g-PSSA membrane had higher water uptake (32.56%), proton conductivity (0.083 S cm −1 ) and excellent hydrophilicity (contact angle 70.78°) than that of Nafion 117. QCM-D results further confirmed its better anti-fouling property vs that of the PVDF-g-PSSA, GO/PVDF-g-PSSA, and Nafion 117 membranes. Moreover, the MFC working with the SGO/PVDF-g-PSSA membrane exhibited the highest maximum power density and best stability of power production after 3 months of operation. CONCLUSION The SGO/PVDF-g-PSSA-1.0 composite PEM can be used as an alternative material to Nafion in MFCs and is conducive to the long-term stable operation of MFCs. © 2018 Society of Chemical Industry
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高影响因子
APPLIED SURFACE SCIENCE
·
2019
·
IF 5.155
Peng Lv,Chongyang Zhao,Woo Jae Lee,Siping Huo,Se-Hun Kwon,Jun Fang,Yang Yang
Zero-dimensional/two-dimensional (0D/2D) TiO 2 /g-C 3 N 4 heterostructural photocatalysts were fabricated via ALD technique. TiO 2 nanoparticles were “site-selectively grown” on g-C 3 N 4 nanosheets and the surface modification induced band engineering of the composite photocatalysts. Thus, the redox properties of the photocatalysts were fine tuned. Under visible light , since only g-C 3 N 4 was excited, TiO 2 was acting as the electron transport channel in the optimized interfacial structures . They effectively suppressed the recombination and facilitated the transfer of photogenerated charges, improving the photocatalytic activity. When both the components were excited under UV–vis light, the dynamic equilibrium of the conduction band positions on these n–n type semiconductor heterojunctions led to the increased recombination rate of charges, decreasing the reactivity for H 2 evolution. However, the photocatalytic degradation of organic pollutants by these composite photocatalysts exhibited enhanced activities, resulting from the photogenerated holes on VB of TiO 2 which could promote oxidation of organic pollutants with strong oxidation potentials. Furthermore, TiO 2 /g-C 3 N 4 photocatalysts with limited numbers of deposition cycles exhibited optimal photocatalytic activity under visible light. In contrast, excessive deposition cycles on g-C 3 N 4 for TiO 2 /g-C 3 N 4 led to continuous film and increased thickness of TiO 2 , resulting in the attenuation of the reactivity. We verified this TiO 2 /g-C 3 N 4 photocatalysts with less mass-loading, but more enhanced photocatalytic activity.
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高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
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2019
·
IF 14.229
Zizheng Ai,Yongliang Shao,Bin Chang,Lei Zhang,Jianxing Shen,Yongzhong Wu,Baibiao Huang,Xiaopeng Hao
As a metal-free polymeric semiconductor, graphitic carbon nitride (g-C 3 N 4 ) is a promising candidate for photocatalytic water splitting but suffers from the insufficient optical absorption and sluggish utilization of photocarriers. Herein, based on the energy band engineering theory, a new design philosophy of tunable p-n homojunction is proposed and realized in a novel P-doped g-C 3 N 4 (PCN) material. Through regulating the tendency of transformation in p-n homojunction, a strong internal electric field is built and integrated with two secondary internal electric fields by further decorating with Ti 3 C 2 , leading to the formation of a triple-internal electric field system. Thus the spatial separation efficiency of photocarriers is improved and their lifetime is prolonged. The specific photocatalyst exhibits excellent overall water splitting performance in pure water with a notable quantum yield. This work presents a peculiar concept of adjustable p-n homojunction and holds great significance for the rational design of advanced photocatalyst in water splitting.
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高影响因子
Arabian Journal of Chemistry
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2024
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IF 5.3
Yuan Li,Jie Zhang,Jie-lin Zhang,Jin-ya Fan,Qian Zhao,Qi-qi Chu,Shi-hong Zhong,Rui Gu
Bang Jian has a long-standing history of medicinal use, noted for its detoxifying effects and the treatment of various fevers, laryngitis, and thermal illnesses. Presently, Gentiana veitchiorum and G. szechenyii are the predominant varieties utilized. However, comparative data on their chemical compositions remains scarce. In this study, employing UPLC-Q-TOF/MS metabolomics, conducted a comprehensive comparison of the chemical constituents in G. veitchiorum and G. szechenyii and assessed their antioxidant activities. Results indicated both varieties exhibit significant antioxidant capabilities, with G. szechenyii displaying superior efficacy. The IC 50 values for DPPH, Hydroxyl, and ABTS in G. szechenyii were determined to be 0.16, 0.48, and 0.80 mg/mL, respectively. Through UPLC-Q-TOF/MS, 56 compounds were identified, revealing notable differences in metabolite composition between the two species. 24 differential metabolites were identified as potential chemometric markers, facilitating the accurate differentiation of G. veitchiorum and G. szechenyii . Correlation analyses identified six compounds—depressine, szechenyin A, syringic acid, isoorientin-2′'-O-glucopyranoside, isoscoparin 2″-O-glucoside, and naringenin—as significant to the variance in antioxidant activity. These findings enhance our understanding of the phytochemical and antioxidant properties of G. veitchiorum and G. szechenyii , offering a theoretical foundation for their clinical application.
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高影响因子
ACS Applied Polymer Materials
·
2025
·
IF 4.7
Yangyi Wu,Lijun Fan,Yixiang Chen,Xianhong Zhang,Dong Chen,Wantai Yang
In this work, a series of nonmigrating polymeric plasticizers with a branched structure, poly(vinyl chloride-co-hydroxyethyl acrylate)-g-polycaprolactone (PVC-co-PHEA-g-PCL), were fabricated by the sequential precipitation copolymerization and ring-opening polymerization (ROP). Initially, the precipitation copolymerization of vinyl chloride monomer with hydroxyethyl acrylate was conducted in a nonaqueous reaction medium by controlling the monomer feed ratio via semibatch to synthesize poly(vinyl chloride-co-hydroxyethyl acrylate) (PVC-co-PHEA) copolymers. The gel permeation chromatography and nuclear magnetic resonance spectroscopy (H NMR) demonstrated that the synthesized PVC-co-PHEA copolymers had low number-average molecular weight (Mn, 8000–12,000 g/mol) and possessed uniform polymer composition (wHEA = 2.9%, 7.0%, and 12.0%). Subsequently, utilizing the hydroxy side-group of the PVC-co-PHEA copolymer as the incipient macroinitiator for the ROP of ε-caprolactone to form a series of PVC-co-PHEA-g-PCLs with different grafting densities and side-chain lengths. Characterization by 1H NMR spectra, wide-angle X-ray diffraction, dynamic mechanical analysis, and differential scanning calorimetry indicated the successful preparation of PVC-co-PHEA-g-PCLs with a branched structure and their suitability as permanent plasticizers in the PVC matrix. The enhancement in both the mechanical strength and superior migration resistance highly verified the strong chain entanglement between PVC-co-PHEA-g-PCLs with the PVC matrix in comparison to the pure dioctyl phthalate (DEHP) and PCL-3000. Moreover, these PVC-co-PHEA-g-PCLs also exhibited outstanding compatibility with the PVC matrix and resulted in the PVC blend with excellent transmittance.
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高影响因子
Journal of Environmental Chemical Engineering
·
2025
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IF 7.2
Weirui Chen,Weijie Chen,Yimin Luo,Yanqi Feng,Xukai Li,Jing Wang,Ping Li,Liying Bin,Bing Tang,Laisheng Li
g-C 3 N 4 (CN) based catalysts were effective for photocatalytic ozonation (PCO), but their stability during reaction remained a mystery. This study investigated the change on PCO activity and stability of CN induced by F or I doping. Compared with CN, F-CN had the greater VB potential while I-CN had a greater CB position, which both led to their better O 3 activation. F-CN and I-CN PCO showed the greater oxalic acid (OA) degradation than that of CN PCO process. Though the enhanced activity, both F-CN and I-CN demonstrated the lower stability compared with that of CN. Because of the existing of reactive oxygen species (ROS) like •OH, •O 2 - and h vb + , CN, F-CN and I-CN were partially oxidized, generating NO 3 - and organic molecules such as cyanuric acid. h vb + and •OH mainly accounted for the decomposition of three CN. Triazine ring oxidation resulted in internal tearing and edge fracture as well as the formation of O-containing groups on all CN-based catalysts. O contents in catalysts initially increased and then decreased with reaction time, indicating that surface O-containing groups were unstable. The structural destroy could be eased with the present of organic pollutants. This study deepened the understanding of fate of CN based catalysts during PCO application.
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高影响因子
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