ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2018
·Vol. 25
·期 21
·21058-21069
·
IF 2.8
Wang Ziyang,Wang Yan,Yu Cong,Zhao Yanxia,Fan Meixia,Gao Baoyu
In this study, a modified sodium alginate (MSA) composited with TiCl 4 was used to treat the synthetic Ag nanoparticles (AgNPs) water in coagulation-ultrafiltration process. The floc properties and membrane fouling of TiCl 4 and MSA composite coagulants (TiCl 4 + MSA) were investigated by a laser diffraction instrument and ultrafiltration fouling model. The recycle of the AgNP-containing flocs was evaluated by XRD and photocatalytic experiments. The results showed that TiCl 4 + MSA could achieve better coagulation performance than TiCl 4 alone with AgNP and DOC removal up to 97 and 59% at the optimum condition (pH = 5 and dosage = 12 mg TiCl 4 /L). TiCl 4 + MSA produced larger and looser flocs than TiCl 4 and TiCl 4 + SA composite coagulant (TiCl 4 + SA), which was benefit for the inhibition of subsequence membrane fouling. The strongly attached external fouling resistance ( R ef-s ) and the reversible internal fouling resistance ( R if-r) of TiCl 4 + MSA were only 43 and 39.2% of those achieved by TiCl 4 at the optimal coagulation condition. Besides, the adopted AgCl-TiO 2 could be recycled from AgNP-containing flocs. And MSA could promote the form of TiO 2 anatase. It gives us a possible way for silver nanoparticle recycle.
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BIOPROCESS AND BIOSYSTEMS ENGINEERING
·
2018
·Vol. 41
·期 9
·1271-1281
·
IF 2.139
Cao Weifeng,Wang Yujue,Luo Jianquan,Yin Junxiang,Wan Yinhua
α,ω -Dicarboxylic acids (DC) are versatile chemical intermediates with different chain length. For biosynthesis of DC, to obtain the highly pure product via crystallization, it is required to remove pigments and proteins in fermentation broth. However, a trade-off between decolorization/deproteinization ratio and DC recovery during the purification process was found, which impeded DC production by fermentation. When ultrafiltration (UF) was applied to treat α,ω -dodecanedioic acid (DC 12 ) broth, 93.4% of DC 12 recovery, 80.5% of decolorization ratio and 61.7% of deproteinization ratio were achieved by a PES 3 membrane. However, the membrane technology could not effectively retain the pigments or proteins with low molecular weight when a high DC 12 permeation was required. Meanwhile, the selected activated charcoal or macroporous resins were not good adsorbents for the present system. Furthermore, an integrated process for decolorization and deproteinization was developed. After filtration with PES3 membrane, an activated charcoal was used to remove the small proteins and pigments in the UF permeate. As a result, 91.4% of DC 12 recovery, 94.7% of decolorization ratio and 84.8% of deproteinization ratio were obtained by such two-stage strategy. These results would serve as a valuable guide for process design and practical operation in subsequent industrial application.
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JOURNAL OF BIOENERGETICS AND BIOMEMBRANES
·
2018
·Vol. 50
·期 4
·297-305
·
IF 2.914
Ma Long,Dong Jia-Xin,Fu Wen-Rong,Li Xue-Yi,Chen Jing,Liu Yi
In this work, the effects of two non-ionic, non-hydroxyl organic solvents, dimethyl sulfoxide (DMSO) and dimethyl formamide (DMF) on the morphology and function of isolated rat hepatic mitochondria were investigated and compared. Mitochondrial ultrastructures impaired by DMSO and DMF were clearly observed by transmission electron microscopy. Spectroscopic and polarographic results demonstrated that organic solvents induced mitochondrial swelling, enhanced the permeation to H + /K + , collapsed the potential inner mitochondrial membrane (IMM), and increased the IMM fluidity. Moreover, with organic solvents addition, the outer mitochondrial membrane (OMM) was broken, accompanied with the release of Cytochrome c , which could activate cell apoptosis signaling pathway. The role of DMSO and DMF in enhancing permeation or transient water pore formation in the mitochondrial phospholipid bilayer might be the main reason for the mitochondrial morphology and function impaired. Mitochondrial dysfunctions induced by the two organic solvents were dose-dependent, but the extents varied. Ethanol (EtOH) showed the highest potential damage on the mitochondrial morphology and functions, followed by DMF and DMSO.
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APPLIED MICROBIOLOGY AND BIOTECHNOLOGY
·
2018
·Vol. 102
·期 14
·6047-6056
·
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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CHINESE JOURNAL OF POLYMER SCIENCE
·
2018
·Vol. 36
·期 8
·970-978
·
IF 2.016
Meng Xiang-Li,Yu Gen-Hua,Ma Jian
Novel poly(aryl ether sulfone ketone)s (PAESK) were synthesized from bisphenol A (BPA), 9,9′-bis(4-hydroxyphenyl) fluorene (BHPF), 4,4′-dichlorodiphenylsulfone (DCS) and 4,4′-difluorobenzophenone (DFB) via nucleophilic substitution polymerization, which were subsequently used to fabricate ultrafiltration membrane by phase-inversion method for high temperature condensed water treatment. The obtained high molecular weight co-polymers with fluorene group with good solubility and good thermal stability, can be easily cast into flexible, white and non-transparent flat films. The influence of molar ratio of BPA and BHPF on the properties of the prepared co-polymers and membranes was investigated in detail. SEM study of the morphology of the membranes indicated that the prepared membranes possessed homogeneous pores on the top surface and were sponge-like or finger-like in cross-section. Pure water flux of the membranes increased from 71.87 L·m −2 ·h −1 to 247.65 L·m −2 ·h −1 , while the retention of BSA decreased slightly, and the water contact angle decreased from 82.1° to 55.6° with the PVP concentration from 0 wt% to 10 wt%. With increasing concentration of PVP, the mechanical properties of membranes decreased, while the thermal stability increased. The permeate flux measurement showed that the PAESK membrane had the potential for high temperature condensed water treatment.
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International Journal of Minerals Metallurgy and Materials
·
2018
·Vol. 25
·期 5
·481-488
·
IF 1.261
Li Zhi-li,Rao Feng,Song Shao-xian,Li Yan-mei,Liu Wen-biao
In saline water flotation, the salinity can cause a distinguishable slime coating of clay minerals on chalcopyrite particles through its effect on their electrical double layers in aqueous solutions. In this work, kaolinite was used as a representative clay mineral for studying slime coating during chalcopyrite flotation. The flotation of chalcopyrite in the presence and absence of kaolinite in tap water, seawater, and gypsum-saturated water and the stability of chalcopyrite and kaolinite particles in slurries are presented. Zeta-potential distributions and scanning electron microscopy images were used to characterize and explain the different slime coating degrees and the different flotation performances. Kaolinite particles induced slime coating on chalcopyrite surfaces and reduced chalcopyrite floatability to the greatest extent when the pH value was in the alkaline range. At 0.24wt% of kaolinite, the chalcopyrite floatability was depressed by more than 10% at alkaline pH levels in tap water. Salinity in seawater and gypsum-saturated water compressed the electrical double layers and resulted in extensive slime coating.
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ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2018
·Vol. 410
·期 18
·4387-4395
·
IF 3.307
Qiu Xiuzhen,Xu Xian-Yan,Chen Xuncai,Wu Yiyong,Guo Huishi
A novel molecularly imprinted quartz crystal microbalance (QCM) sensor was successfully prepared for selective determination of sialic acid (SA) in human urine samples. To obtain the QCM sensor, we first modified the gold surface of the QCM chip by self-assembling of allylmercaptane to introduce polymerizable double bonds on the chip surface. Then, SA molecularly imprinted polymer (MIP) nanofilm was attached to the modified QCM chip surface. For comparison, we have also characterized the nonmodified and improved surfaces of the QCM sensor by using atomic force microscopy (AFM) and Fourier transform infrared (FTIR) spectroscopy. We then tested the selectivity and detection limit of the imprinted QCM sensor via a series of adsorption experiments. The results show a linear response in the range of 0.025–0.50 μmol L −1 for sialic acid. Moreover, the limit of detection (LOD) of the prepared imprinted QCM sensor was found to be 1.0 nmol L −1 for sialic acid, and high recovery values range from 87.6 to 108.5% with RSD < 8.7 ( n = 5) for the spiked urine sample obtained. Overall, this work presents how a novel QCM sensor was developed and used to detect sialic acid in human urine samples.
Specific recognition of sialic acid by the MIP-QCM sensor system
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CHEMICAL RESEARCH IN CHINESE UNIVERSITIES
·
2018
·Vol. 34
·期 3
·363-368
·
IF 1.248
Ma Lian,Xu Bin,Liu Leijing,Tian Wenjing
A label-free fluorescent aptasensor for specific and ultrasensitive monitoring ochratoxin A(OTA) was developed using the specific aptamer of OTA(OSA) as recognition element, an aggregation-induced emission(AIE) molecule(a 9,10-distyrylanthracene with two ammonium groups, DSAI) as a fluorescent probe, and graphene oxide(GO) as a quencher. In the absence of OTA, the AIE probe DSAI and OSA complex(DSAI/OSA) is adsorbed on the GO surface, and the fluorescence of DSAI will be quenched efficiently via the fluorescence resonance energy transfer(FRET) from DSAI to GO. Upon the OTA addition, a more stable complex(OSA-OTA) is formed and released from GO. Meanwhile, DSAI and OSA-OTA can form a new complex(DSAI/OSA-OTA), then the fluorescent signal of DSAI recovers gradually. Therefore, by introducing GO and DSAI, the fluorescence signal of DSAI can be easily turned from “off” to “on” after the addition of OTA, and the ultrasensitive detection of OTA by monitoring the change of the fluorescence signal of DSAI can be readily realized. The detection limit of the assay can reach 0.324 nmol/L with a linear detection range of 10—200 nmol/L. And the aptasensor exhibits high selectivity for OTA against other analogues. Moreover, it has been successfully applied for the detection of OTA in red wine samples.
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JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
·
2018
·Vol. 134
·期 2
·1071-1082
·
IF 2.209
Zhou Shaojie,Qian Yi,Chen Xilei,Li Long
Layered double hydroxides-silicon dioxide hybrids (LDH-Si) were in situ synthesized by a co-precipitation method. Flame-retardant, smoke suppression and thermal degradation properties of the LDH-Si in ethylene-vinyl acetate (EVA) composites were studied using cone calorimeter test (CCT), limiting oxygen index (LOI), smoke density test (SDT), and thermogravimetry–Fourier transform infrared spectrometry. The CCT results indicated that the peak heat release rate and peak smoke production rate of the EVA/LDH-Si composite with 2.5 mass% SiO 2 were decreased by 28.5 and 21.9% compared to EVA/LDH composite, respectively. The LOI results showed that a suitable addition of SiO 2 can significantly enhance the LOI values of the EVA composites. It was obtained from SDT that SiO 2 could help smoke suppression. The EVA/LDH-Si composites possessed a higher thermal stability than the EVA/LDH composites at high temperatures.
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JOURNAL OF MATERIALS SCIENCE
·
2018
·Vol. 53
·期 8
·6239-6250
·
IF 2.993
Chi Dequan,Liu Fei,Hao Chuncheng,Chen Jing,Na Haining,Zhu Jin
The conformational transition of cyclohexylene ring has been recognized as the secondary transition of polyesters containing this aliphatic ring structure. Previously, the stereochemistry, i.e., trans / cis ratio, has been identified as an important factor that has a significant impact on the conformational transition of the cyclohexylene ring. In this paper, we have proposed and proved the side chain effect as another important factor that plays the same role as the stereochemistry, due to the fact that the conformational transition of the ring is usually associated with the coupled motion of it with neighboring unit. Our strategy is to design and synthesize a series of polyesters with 1,4-cyclohexanedicarboxylic acid and diols with different side chains. Polyester without any side chain has the lowest secondary relaxation temperature ( T
β
). Incorporation of asymmetric short side chain will result in increased T
β
, since it will reduce the coupled motion of the neighboring unit with the cyclohexylene ring during the conformational transition process, and thus reduces the flexibility of the chain and increases steric hindrance. However, further incorporation of long side chain will result in decreased T
β
because of the plasticization effect. Moreover, we also found that polyesters with low T
β
tend to have not only better impact strength, but also good ductility and elasticity. Our study enables people to take advantage of the cyclohexylene ring structure for the design and synthesis of thermoplastic and elastomer with better performance.
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JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2018
·Vol. 29
·期 7
·6068-6076
·
IF 2.324
Zhou Jianping,Wang Jianfeng,Li Hua,Shen Fenglei
Using propylene carbonate (PC) as solvent, a hybrid gel polymer electrolyte (GPE) based on poly(propyleneglycol) bis(2-aminopropyl ether) (2-APPG) and 3-isocyanatepropyltriethoxysilane (ICS) was successfully synthesized by sol–gel method. The result shows the hybrid gel polymer electrolyte with [O]/[Li] ratio of 22 has a high ionic conductivity, good thermal stability, as well as good electrochemical stability. The ionic conductivities reach as high as 1.43 × 10 − 3 S cm − 1 at 30 °C and 3.36 × 10 − 3 S cm − 1 at 100 °C, respectively. Nearly 0 weight loss was observed up to 100 °C. The electrochromic device is fabricated by using the hybrid gel polymer as electrolyte. The results demonstrate its high coloration efficiency (267.4 cm 2 C − 1 ) and long cycle life (150 cycles with the linear potential sweep between − 3.5 and + 2.5 V), When the applying voltage is increased to as high as 5 V on the electrochromic device, a fast response is obtained (colored/bleached time are 13/19 s), which indicates its potential application under high voltage conditions.
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Nanoscale Research Letters
·
2018
·Vol. 13
·期 1
·1-5
·
IF 3.125
Han Zhenzhen,Li Nan,Shi Aihua,Wang Haohua,Ma Feng,Lv Yi,Wu Rongqian
A SeO 2 ethanol solution as the facile precursor has been used for the preparation of quaternary Cu 2 ZnSnSe 4 (CZTSe) nanoplates. Monodispersed single-phase CZTSe nanoplates have been prepared successfully by a facile one-pot thermal chemical method. The as-prepared CZTSe nanoplates show uniform morphology with a bandgap of ~ 1.4 eV. As a proof of concept, the CZTSe nanoplates have been used as a visible-light-driven photocatalyst for Rhodamine B dye degradation and show high photocatalytic activity and stability. The excellent dye removal is mainly ascribed to the efficient light utilization of CZTSe nanoplates.
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