CHEMICAL ENGINEERING JOURNAL
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2020
·
IF 10.652
Yongkui Li,Xianjin Qi,Guohua Li,Hua Wang
Nonferrous smelting wastewaters containing high levels of arsenic and sulfuric acid threaten human health and ecological environments due to insufficient disposal technologies and/or possible leakages during transportation to long-term storage facilities. Chemical precipitation is one important route for arsenic removal and immobilization via the formation of arsenic-stabilized minerals. In this study, we propose a new strategy for the treatment of wastewaters containing high levels of arsenic using pyrite as an in situ S and Fe source to prepare environmentally friendly scorodite and As 2 S 3 precipitates. Dissolved pyrite release (S-II) and Fe (II) ions in highly acidic wastewater, both of which drive arsenic precipitation. Sulfide ions readily react with As(III) to generate the stable As 2 S 3 while Fe(II)/As(III) were oxidized to Fe(III)/As(V) by H 2 O 2 . The reaction between Fe(III) and As(V) took place on the pyrite surface as a nucleation site to form amorphous ferric arsenate that ultimately transformed into crystalline scorodite. Sulfide ions were oxidized to H 2 SO 4 that further promoted pyrite dissolution. Up to 99.4% of arsenic was successfully removed from copper smelting wastewaters with an initial arsenic concentration of 11200 mg/L. The concentration of leached As from the As-bearing precipitate was 1.78 mg/L under optimized conditions, which were: a 1.4 FeS 2 /As molar ratio, an initial solution pH of 2, an H 2 O 2 /As molar ratio of 1%, a reaction temperature of 90 °C, and a reaction time of 12 h. In summary, a prospective process successfully shows arsenic removal and immobilization from smelting wastewater, and further demonstrates the potential for the efficient and affordable disposal of wastewater.
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POLYMER
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2020
·
IF 4.231
Ke Wang,Qi Liu,Guiyan Liu,Yongfei Zeng
The study of thermoresponsive homopolymers has attracted great attention due to their broad application value. Herein, a series of novel thermoresponsive homopolymers of poly[oligo(ethylene glycol) (acyloxy) methacrylate]s containing oligo(ethylene glycol) (OEG) units and substituent groups of ester have been designed and prepared by RAFT polymerization . The solution properties of these polymers have been investigated in detail, which indicate that most of them exhibit lower critical solution temperature (LCST) in water and upper critical solution temperature (UCST) in alcohols, and their LCST-type or UCST-type cloud point temperature ( T CP L or T CP U ) is closely related to the OEG units and ester groups. Furthermore, the parameters affecting the thermoresponse of these polymers including polymerization degree (DP) and concentration have also been investigated. The present work not only discovers a series of novel thermoresponsive polymers, but also has certain guiding significance on the understanding of molecular structure and thermoresponsive property relationships, which is useful for the design of new thermosensitive polymers.
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ANALYTICA CHIMICA ACTA
·
2019
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IF 5.256
Yunqing Wu,Yuxin Chen,Shiqin Zhang,Lizhi Zhang,Jingming Gong
A novel and ultrasensitive electrochemiluminescent (ECL) bioassay has been developed for the detection of atrazine (ATZ), whereby bifunctional S, N-codoped carbon dots (S, N-CDs) and activated mesoporous bicarbons (BCs) have been innovatively integrated to synergistically amplify the ECL signal. When endogenous dissolved O 2 is used as a coreactant, its sluggish reduction hinders the enhancement of ECL intensity of the luminophore, thus restricting its further application in bioanalysis . Here, bifunctional S, N-CDs severe as not only the ECL luminophore but the coreaction accelerator of dissolved O 2 to generate more intermediates to boost the coreaction without using any other coreactant and coreaction accelerator. The as-formed nanoarchitectures of BCs possess enlarged surface area as the nanocarriers . They could provide adequate active sites for immobilization of tyrosinase (Tyr), which greatly prompts the ECL bioassay applications. Such a smart integration of bifunctional S, N-CDs, activated mesoporous BCs and the enzyme inhibition reaction achieves a unique and attractive high-performance signal-on ECL bioassay, realizing ultrasensitive detection of ATZ. Under the optimal condition, this bioassay exhibits two linear ranges, from 0.0001 to 0.01 μg L −1 and 0.01–20 μg L −1 with a detection limit of 0.08 ng L −1 at signal to noise ratio of 3. The as-fabricated assay is sensitive and economical, opening a new way for the enhancement of ECL signal output and a versatile strategy for ultrasensitive ECL bioanalysis.
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POLYMER DEGRADATION AND STABILITY
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2020
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IF 4.032
Guoqiang Wang,Meichao Hou,Min Jiang,Rui Wang,Yin Liang,Guangyuan Zhou
A series of poly (propylene naphthalate-co-propylene 2,5-furandicarboxylate)s (PPNFs) were synthesized by the melt polycondensation method from 2,5-furandicarboxylic acid (FDCA), 2,6-naphthalenedicarboxylic acid (2,6-NDCA) and 1,3-propanediol (1,3-PDO). Their composition and sequence distribution were analyzed by 1 H NMR and 13 C NMR. Crystallization behaviors , thermal and mechanical properties were investigated. The weight-average molecular weights of PPN, PPF and PPNFs were higher than 28 000 g mol −1 and the polydispersity index was between 2.1 and 2.7. DSC and XRD results show that poly (propylene 2,5-furandicarboxylate) (PPF) and poly (propylene naphthalate) (PPN) are semi-crystalline polymers, but all PPNFs are amorphous polymers. With increasing the content of FDCA, the initial temperature of α-relaxation rose significantly. When the content of FDCA was 74 mol%, PPNF74 exhibited the high bio-based content (77.6 wt%) and good mechanical properties ( σ m = 71 MPa and ε b = 146%).
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Catalysis Science & Technology
·
2021
·Vol. 11
·期 16
·5663-5670
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IF 6.119
Mengqi Xue,Daochuan Jiang,Haiwei Du,Zhongjun Li,Hong Bi,Yupeng Yuan
Localizing charge carriers close to catalytically active sites can reduce the charge recombination in photoexcited polymeric carbon nitride (PCN), which thus potentially increases its photocatalytic H2 generation. However, this strategy has not been applied to enhance the photocatalytic performance of PCN. Herein density functional theory (DFT) calculations unravel that N defect (Ndefect) engineered tri-s-triazine units form a highly localized mid-gap state in PCN, which can localize the π electrons for efficient separation of electrons and holes. Moreover, Ndefect engineered tri-s-triazine units impart the lowest Gibbs free energy barrier of −0.129 eV for the reduction of H+ to adsorbed H, thereby serving as the catalytically active sites. Enlightened by theoretical results, the Ndefect engineered tri-s-triazine units were created via post oxidation of PCN in an electronic furnace. Such PCN with N defects offers an increased photocatalytic H2 generation under visible light exposure. The highest H2 generation rate is up to 98.1 μmol h−1, 3.8 times higher than that by using pristine PCN (26.1 μmol h−1). This work manifests the significance of localizing charge carriers close to the catalytically active sites for increased photocatalytic performance of PCN.
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Journal of Cleaner Production
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2021
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IF 9.297
Gang Zhou,Yuying Wu,Peifang Wang,Hao Li,Rong Huang,Yitong Liu,Junhong Guo
Exploring photocatalysts to accelerate heavy metal Cr(VI) photoreduction is of great significance. Different from traditional strategies, this work proposes a simple and feasible strategy to construct cadmium/rhenium sulfide (CdS/ReS2) S-scheme heterojunctions for enhancing carrier separation through a covalent-anion-driven self-assembling approach. Herein, the construction of internal electric field induced by an atomic-hybridization at CdS/ReS2 interface drives the photoexcited electrons from one-dimensional CdS nanowires to two-dimensional ReS2 nanosheets upon light irradiation, resulting in the formation of an S-scheme carrier kinetic pathway, which enables the separation of electron-hole pairs to accelerate Cr(VI) photoreduction . As a result, the reduction reaction of CdS/ReS2 heterojunction is increased about 11.4 and 24.3 times compared to pristine CdS and ReS2. Our findings provide a new insight in regulating carrier transfer pathway and designing new-type photocatalysts .
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CHEMICAL ENGINEERING JOURNAL
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2021
·
IF 13.273
Guijun Li,Yibo Tang,Tiantian Fu,Yang Xiang,Zhongping Xiong,Yujun Si,Chaozhong Guo,Zhiqiang Jiang
The development of efficient and cost-effective bifunctional electrocatalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is crucial for the commercialization of rechargeable metal-air batteries. Herein, the pyrolysis of a precursor containing g-C 3 N 4 , thiourea, cobalt chloride and ferric chloride was used to fabricate S, N co-doped carbon nanotubes functionalized with Co 3 Fe 7 alloy nanoparticles (CoFe/S-N-C). The obtained CoFe/S-N-C catalyst exhibited an ORR half wave potential of 0.855 V ( vs . RHE) in 0.1 M KOH, outperforming a commercial Pt/C catalyst ( E 1/2 = 0.844 V). The catalyst also demonstrated superior OER catalytic activity (1.588 V at 10 mA cm −2 ) relative to RuO 2 in 0.1 M KOH, thus displaying outstanding bifunctional ORR and OER activity. A rechargeable Zn-air battery fabricated using CoFe/S-N-C shows good very performance (maximum power density of 120 mW cm −2 with a specific capacity of 814 mAh g −1 ) which was superior to a Zn-air battery fabricated using Pt/C and RuO 2 as ORR and OER catalysts (92 mW cm −2 and 787 mAh g −1 , respectively). Further, the fabricated battery using CoFe/S-N-C showed good stability, offering a discharge voltage ∼ 1.10 V and a recharge voltage ∼ 2.15 V at 10 mA cm −2 over 300 cycles, evidence of the durability of the CoFe/S-N-C catalyst.
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Catalysis Science & Technology
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2021
·Vol. 11
·期 19
·6498-6506
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IF 6.119
Shengxin Chen,Ran An,Yingwei Li,Yuting Zhu,XinBao Zhu,Ruixia Liu,Xingang Li
Although poly(ionic liquid)s (PILs) have received extensive attention and research, the strategy for designing efficient PILs catalysts remains a challenge. This work reports a series of efficient PILs catalysts with increasing ionic ratio and various anion species to regulate electrophilic/nucleophilic ability, and explores the effect of the ionic ratio on the coupling reaction of propylene oxide (PO) with CO2 or methanol. These PILs are synthesized by a quaternization reaction between poly(N-vinylimidazole) (PVIM) and dihaloalkanes, where the amount of crosslinker of dihaloalkanes controls the ionic ratio of PILs, further affecting their microcosmic environment, morphologies and properties. It is noteworthy that the ionic ratio with IL units and imidazoline group can work as a trigger and promoter in the coupling reaction of PO with CO2 or methanol. The ionic ratio could open the reaction compared with the parent PVIM and the choice of anion could turn the reaction on or off. It suggested that the active microstructure and electrophilic/nucleophilic ability of PILs could be regulated by the ionic ratio. In these active sites, the IL units-connected imidazoline group could weaken the interaction of the cation–anion, giving enhanced leaving ability of the anion, contributing to the excellent catalytic performance.
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ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2019
·Vol. 411
·期 29
·7737-7745
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IF 3.286
Pan Daodong,Xun Mingyue,Lan Hangzhen,Li Jianlin,Wu Zhen,Guo Yuxing
A newly developed molecularly imprinted photonic polymer (MIPP) film, which was prepared by colloidal crystal templating and surface molecular imprinting, was used for selective capture of S-layer protein (SLP) from a complex Lactobacillus acidophilus sample. The colloidal crystal templates were formed by a dipping process followed by chemical binding of the imprinted template SLP molecules. A sandwich structure consisting of two glass slides was formed after the SLP–silica layer had been covered with a poly(methyl methacrylate) glass slide. After polymerization of the SLP–silica layer with the preprepared polymerization solution, hydrofluoric acid and acetic phosphate buffer solutions removed the silica particles and SLP molecules, respectively. The MIPP film obtained exhibited a three-dimensional, highly ordered and interconnected macroporous structure (pore size greater than 200 nm), which is specifically accessible to SLP molecules. The adsorbed SLP molecules were simply and straightforwardly detected by a fiber-optic spectrometer. The redshift of the Bragg diffraction peak of the MIPP film was linearly related to the number of SLP molecules that had been harvested in the film. The detection limit of the SLP–MMIP–fiber-optic spectrometer method for SLP was 1 ng mL -1 . The MIPP sensor was successfully applied to detect SLP molecules in a crudely extracted Lactobacillus acidophilus sample. Our results prove the applicability of the SLP–MIPP film for fast and real-time measurement of SLP.
Graphical abstract
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Inorganic Chemistry Frontiers
·
2018
·Vol. 5
·期 6
·1415-1422
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IF 5.106
Ailijiang Abudurusuli,Kui Wu,Yilimiranmu Rouzhahong,Zhihua Yang,Shilie Pan
Four new quaternary chalcogenides with the formula of Na6Zn3MIII2Q9 (MIII = Ga, In; Q = S, Se) have been successfully synthesized for the first time. They are isostructural and crystallize in the monoclinic C2/c space group. As seen from their structures, they exhibit two opposite direction layers composed of the interconnection of countless (Zn/MIII)10Q20 supertetrahedra (T3-type) clusters, and then three coordination-type NaQn units (n = 4–6) exist among the interlayers to bridge them together. Note that these T3 clusters connect with each other by vertex-sharing to form the layers in the title compounds, which can be viewed as the first discovered examples in the known quaternary chalcogenides that only exhibit the tetrahedron-sharing T3 clusters. Moreover, we have also systematically compared the structural differences of all the T3-containing quaternary chalcogenides and the result shows that the title compounds possess the shortest interlayer spacing and more tilting T3 cluster-built layers in comparison with other related compounds. The measured optical properties indicate that their optical bandgaps are in the range from 2.22 to 3.15 eV, respectively. The photoluminescence result shows that the title compounds have potential application prospects as blue and green light emitters in view of their obvious emission peaks centered at 463 and 541 nm. Electronic structures and density of states were also calculated by first-principles calculations and the results indicate that their optical bandgaps are mainly determined by the T3 clusters.
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APPLIED MICROBIOLOGY AND BIOTECHNOLOGY
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2018
·Vol. 102
·期 14
·6047-6056
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IF 3.34
Zhang Zhi-Jun,Cai Rui-Feng,Xu Jian-He
A nitrilase from Hoeflea phototrophica DFL-43 (HpN) demonstrating excellent catalytic activity towards benzoylacetonitrile was identified from a nitrilase tool-box, which was developed previously in our laboratory for ( R )- o -chloromandelic acid synthesis from o -chloromandelonitrile. The HpN was overexpressed in Escherichia coli BL21 (DE3), purified to homogeneity by nickel column affinity chromatography, and its biochemical properties were studied. The HpN was very stable at 30–40 °C, and highly active over a wide range of pH values (pH 6.0–10.0). In addition, the HpN could tolerate against several hydrophilic organic solvents. Steady-state kinetics indicated that HpN was highly active towards benzoylacetonitrile, giving a K M of 4.2 mM and a k cat of 170 s −1 , the latter of which is ca. fivefold higher than the highest record reported so far. A cascade reaction for the synthesis of optically pure ( S )-β-phenylalanine from benzoylacetonitrile was developed by coupling HpN with an ω-transaminase from Polaromonas sp. JS666 in toluene-water biphasic reaction system using β-alanine as an amino donor. Various ( S )-β-amino acids could be produced from benzoylacetonitrile derivatives with moderate to high conversions (73–99%) and excellent enantioselectivity (> 99% ee ). These results are significantly advantageous over previous studies, indicating a great potential of this cascade reaction for the practical synthesis of ( S )-β-phenylalanine in the future.
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POLYMERS FOR ADVANCED TECHNOLOGIES
·
2018
·Vol. 29
·期 10
·2665-2673
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IF 2.137
Xiaodong Guo,Xin Wang,Xiongrui Liu,Yanyang Zheng,Jianzhong Xu,Haiyun Ma
A phosphazene derivative flame retardant with a highly cross-linked microsphere structure, named poly(cyclotriphosphazene-c-sulfonyldiphenol) (PCPS) microspheres, were synthesized by 1-pot reaction and then applied on flame retarded epoxy (EP) resin. The microstructure and chemical composition of PCPS microspheres were characterized using scanning electron microscopy, transmission electron microscopy, and element mapping. The thermal stability of PCPS microspheres and PCPS/EP composites was explored through thermogravimetric analysis. Thermogravimetric data showed that the PCPS microspheres have excellent thermal stability, and the char yield is about 43% at the end of 800°C. The incorporation of PCPS microspheres significantly increased the char yield of PCPS/EP composites. The flammability was investigated by limited oxygen index tests and cone calorimeter. The limited oxygen index value of PCPS/EP composite was increased to 29.8 from 26.6 when 3 wt% of PCPS microspheres was added. Compared with neat EP, the flame retardancy was greatly improved. The peak heat release rate and smoke production rate of PCPS/EP composites were reduced by 45.0% and 43.6%, respectively. The mechanical properties including tensile strength and modulus were both improved due to the enhancement of PCPS microspheres. The PCPS microspheres act as a dual function for improving both the flame resistance and mechanical strength of PCPS/EP system.
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