CELLULOSE
·
2019
·Vol. 26
·期 18
·9863-9875
·
IF 3.917
Wang Jinran,Wan Jinquan,Ma Yongwen,Wang Yan
Abstract The deinking of mixed office waste paper by cellulase, M/Las (modification of laccase aspartic acid system), and C-M/Las (cellulase synergistic modification of laccase aspartic acid system) was investigated. The fiber morphology parameters, hydrogen bond patterns, cellulose crystallinity, and fiber microstructure were observed via fiber quality analyzer (FQA), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The results showed that the effective residual ink concentration of enzyme deinked pulp decreased compared with blank pulp (pulp without enzymatic treatment). The deinking efficiencies of C-M/Las, cellulase, and M/Las were 18.17%, 14.01%, and 12.31%, respectively. FQA analysis indicated that the fiber length and curl index decreased, while the fiber width slightly increased. FTIR analysis revealed that after cellulase, M/Las, and C-M/Las treatment, the content of intermolecular hydrogen bonds increased by 14.65%, 13.37%, and 19.80%, respectively. This indicates that there is a synergistic effect between cellulase and M/Las. XRD showed that the cellulose crystallinity decreased after enzymatic deinking. SEM micrographs of fibers treated with enzymes revealed that the fiber surface became rough and more fibrils appeared. The water retention value was increased after enzymatic deinking. Graphic abstract
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JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
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2019
·Vol. 30
·期 19
·18246-18258
·
IF 2.195
Yu Zongxue,Feng XiaoFang,Min Xia,Li XiuHui,Shao LiangYan,Zeng HaoJie
In the study, the reduced graphene oxide/graphitic Bi 12 O 17 Cl 2 –TiO 2 heterojunctions sheet membrane(RGO/PDA/Bi 12 O 17 Cl 2 –TiO 2 ) was fabricated by the dopamine modification and assembling the RGO/PDA/Bi 12 O 17 Cl 2 –TiO 2 composites on the surface of commercial CA(cellulose acetate) membrane to degrade methylene blue (MB) and p-chlorophenol (4-CP) to harmless products. These membrane materials were comprehensively characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and UV–vis diffuse reflectance spectra (DRS). The results showed that RGO/PDA/Bi 12 O 17 Cl 2 –TiO 2 nanofiber membrane exhibited extremely high degradation performance with a good distribution of RGO/PDA/Bi 12 O 17 Cl 2 –TiO 2 on the CA nanofiber membrane surface. Besides, the complete photodegradation of 100 mL MB (15 mg L −1 ) solution and 100 mL 4-CP (15 mg L −1 ) solution with artificial visible-light was achieved after 100 min and 160 min, respectively. The RGO/PDA/Bi 12 O 17 Cl 2 –TiO 2 -CA composite membrane revealed the ability of continuous and simultaneous flow-through separation of oil/water emulsion and degradation of soluble organic dye under visible-light irradiation in a short time. Moreover, the nanofiber membranes exhibited excellent stability and reusability for MB-containing oil–water mixed emulsion separation has great potential to be applied in industrial application.
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JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
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2020
·Vol. 31
·期 3
·2699-2707
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IF 2.22
Zhang Jianxia,Li Haiying,Li Yu,Zhao Bing,Ju Xiangnan,Chen Wenbin,Lu Bingliang,Zeng Xiangan,Liu Li
This paper reports the preparation of an excellent acetone gas-sensitive material consisting of a Eu 3+ -decorated α-Fe 2 O 3 microflower (EFM) composite film by a simple hydrothermal and calcination method. For comparison, pure α-Fe 2 O 3 microflowers (PFM) are prepared with the same method. Scanning electron microscopy (SEM) images show that the samples are a loose 3D flower-like structure with many voids surrounded by many thin nanosheets. The structure of the samples was investigated using X-ray diffraction and X-ray photoelectron spectroscopy (XPS). The PFM and EFM gas sensors were systematically tested for gas sensitivity at an optimum temperature of 145 °C. The sensitivity of the EFM gas sensor with 50 ppm of acetone gas was 83, which was up to four times that of the PFM sensitivity (19). The EFM sensor had an extremely fast response time (4 s) and recovery time (38 s). Moreover, the minimum concentration of acetone that we could detect was 0.1 ppm with a response value of 2.1. The enhancement of gas sensitivity was attributed to the high catalytic activity of the Eu 3+ additive.
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JOM
·
2019
·Vol. 72
·期 9
·3186-3194
·
IF 2.305
Li Yun,Yang Shenghai,Taskinen Pekka,He Jing,Chen Yongming,Tang Chaobo,Jokilaakso Ari
This study proposed a cleaner pyrometallurgical lead-acid battery (LAB) recycling method for lead extraction and sulfur conservation without an excessive amount of SO 2 generation. A reducing atmosphere was introduced to the lead paste recycling system to selectively reduce PbSO 4 to PbS. At the same time, PbO and PbO 2 components contained in the lead paste were also reduced to metallic Pb. Then, the intermediate PbS further reacted with a sulfur-fixing agent, typically Fe 3 O 4 , to generate PbO and FeS. Sulfur was transformed from PbSO 4 to PbS and finally conserved as FeS. Thus, SO 2 emissions and pollution were significantly eliminated. This work investigated the thermodynamic and experimental feasibility and phase conversion mechanism of this proposed method, the detailed lead extraction and sulfur fixing mechanisms were clarified, and the phase transformation and microstructural evolution processes were characterized. Additionally, a bench experiment of industrial, end-of-life LAB paste was conducted to detect the lead recovery and sulfur fixation efficiency.
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JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY
·
2019
·Vol. 323
·期 2
·993-1002
·
IF 1.186
Ma Zhili,Wang Yanfei,Luo Yige,Xie Xiaoqing,Xiong Zeng
Highly crosslinked organic–inorganic hybrid polymer poly(cyclotriphosphazene-co-melamine) microspheres (PZM) were synthesized by a simple method. The microspheres was characterized by FTIR, SEM and EDX. It was applied to eliminate thorium(IV) from aqueous solution under various conditions, i.e., pH, initial concentration, dosage and contact time. The experimental data were well-imitated via the pseudo-second-order kinetic model and its adsorption processes comply with the Langmuir isotherm model. Adsorption thermodynamic studies demonstrated that the adsorption process, in essence, was spontaneous and endothermic. Furthermore, the maximum experimental adsorption capacity was 98.6 mg g −1 for initial thorium(IV) concentration 50 mg L −1 . When pH = 0.0, the thorium(IV) removal efficiency reached at 76.9%, which indicates that the adsorbent can also was used in a peracid environment. Adsorption behavior of thorium(IV) onto the microspheres were weakly affected via temperature, implying that adsorption would be done at room temperature.
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CHINESE JOURNAL OF POLYMER SCIENCE
·
2019
·Vol. 38
·期 2
·143-150
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IF 2.804
Yang Sheng-Qing,Zhao Jin-Nan,Zhao Jing-Bo,Zhang Jun-Ying
Cross-linked polyamides (cPAs) were prepared through direct bulk Michael addition and subsequent polycondensation. Several mixed hexanediamine multi-esters (HDAMEs) were generated through the Michael addition of 1,6-hexanediamine (HDA) and methyl acrylate (MA) at 50 °C with different HDA/MA molar ratios. Melt polycondensation of HDAMEs then proceeded at 150 or 170 °C in flasks to obtain viscous fluids, and curing was continued in tetrafluoroethylene molds to obtain cPA films. The Michael addition was monitored on the basis of FTIR and ESI-MS spectra. The cPA films were characterized by DSC, TGA, dynamic mechanical analysis, and tensile test. These directly prepared cPAs exhibited T g of 1–39 °C, tensile strength of up to 45 MPa, and strain at break from 18% to 40%. The cPAs with high tensile strength and good toughness were successfully synthesized through the direct bulk Michael addition from HDA and MA followed with polycondensation.
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Microbial Cell Factories
·
2019
·Vol. 18
·期 1
·1-10
·
IF 4.402
Tao Weiyi,Lin Junzhang,Wang Weidong,Huang He,Li Shuang
Background Bioemulsifiers are surface-active compounds, which exhibit advantages including low toxicity, higher biodegradability and biocompatibility over synthetic chemical surfactants. Despite their potential benefits, some obstacles impede the practical applications of bioemulsifiers, including low yields and high purification costs. Here, we aimed to exploit a novel protein bioemulsifier with efficient emulsifying activity and low-production cost, as well as proposed a design-bioemulsifier system that meets different requirements of industrial emulsification in the most economical way. Results The esterase AXE was first reported for its efficient emulsifying activity and had been studied for possible application as a protein bioemulsifier. AXE showed an excellent emulsification effect with different hydrophobic substrates, especially short-chain aliphatic and benzene derivatives, as well as excellent stability under extreme conditions such as high temperature (85 °C) and acidic conditions. AXE also exhibited good stability over a range of NaCl, MgSO 4 , and CaCl 2 concentrations from 0 to 1000 mM, and the emulsifying activity even showed a slight increase at salt concentrations over 500 mM. A design-bioemulsifier system was proposed that uses AXE in combination with a variety of polysaccharides to form efficient bioemulsifier, which enhanced the emulsifying activity and further lowered the concentration of AXE needed in the complex. Conclusions AXE showed a great application potential as a novel bioemulsifier with excellent emulsifying ability. The AXE-based-designer bioemulsifier could be obtained in the most economical way and open broad new fields for low-cost, environmentally friendly bioemulsifiers.
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JOURNAL OF SOLID STATE ELECTROCHEMISTRY
·
2019
·Vol. 23
·期 11
·3031-3041
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IF 2.531
Deng Yafeng,Ma Zhanhong,Ren Fengzhang,Wang Guangxin
In spite of the TiO 2 compact layer (TCL) being widely used, it still needs more study. This paper took Ni-doped TCLs as the research target, using an innovative two-step method perfectly prepared Ni-doped TCLs with different thicknesses. And then on the basis of Ni-doped TCLs, the TiO 2 nanorod array (TNA) films were successfully prepared. The effects of Ni-doped TCLs with different thicknesses on the morphology, structure, and photoelectric performance of TNA films were investigated. The results indicated that Ni-doped TCLs with appropriate thickness can significantly improve performance of TNA films and obtain satisfactory PCE stability with time. Compared with the TNA films based on Ni:TCL5, Ni:TCL10, and Ni:TCL30, the TNA film with Ni:TCL20 exhibited better comprehensive photoelectric performance, the DSSCs based on this TNA film achieved the highest J sc (10.191 mA cm −2 ), V oc (0.574 V), PCE (4.42%), and the most excellent PCE stability with time.
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Biotechnology for Biofuels
·
2019
·Vol. 12
·期 1
·1-18
·
IF 5.452
Pang Yaru,Zhao Yakun,Li Shenglong,Zhao Yu,Li Jian,Hu Zhihui,Zhang Cuiying,Xiao Dongguang,Yu Aiqun
Background Limonene is an important biologically active natural product widely used in the food, cosmetic, nutraceutical and pharmaceutical industries. However, the low abundance of limonene in plants renders their isolation from plant sources non-economically viable. Therefore, engineering microbes into microbial factories for producing limonene is fast becoming an attractive alternative approach that can overcome the aforementioned bottleneck to meet the needs of industries and make limonene production more sustainable and environmentally friendly. Results In this proof-of-principle study, the oleaginous yeast Yarrowia lipolytica was successfully engineered to produce both d -limonene and l -limonene by introducing the heterologous d -limonene synthase from Citrus limon and l -limonene synthase from Mentha spicata , respectively. However, only 0.124 mg/L d -limonene and 0.126 mg/L l -limonene were produced. To improve the limonene production by the engineered yeast Y. lipolytica strain, ten genes involved in the mevalonate-dependent isoprenoid pathway were overexpressed individually to investigate their effects on limonene titer. Hydroxymethylglutaryl-CoA reductase (HMGR) was found to be the key rate-limiting enzyme in the mevalonate (MVA) pathway for the improving limonene synthesis in Y. lipolytica . Through the overexpression of HMGR gene, the titers of d -limonene and l -limonene were increased to 0.256 mg/L and 0.316 mg/L, respectively. Subsequently, the fermentation conditions were optimized to maximize limonene production by the engineered Y. lipolytica strains from glucose, and the final titers of d -limonene and l -limonene were improved to 2.369 mg/L and 2.471 mg/L, respectively. Furthermore, fed-batch fermentation of the engineered strains Po1g KdHR and Po1g KlHR was used to enhance limonene production in shake flasks and the titers achieved for d -limonene and l -limonene were 11.705 mg/L (0.443 mg/g) and 11.088 mg/L (0.385 mg/g), respectively. Finally, the potential of using waste cooking oil as a carbon source for limonene biosynthesis from the engineered Y. lipolytica strains was investigated. We showed that d -limonene and l -limonene were successfully produced at the respective titers of 2.514 mg/L and 2.723 mg/L under the optimal cultivation condition, where 70% of waste cooking oil was added as the carbon source, representing a 20-fold increase in limonene titer compared to that before strain and fermentation optimization. Conclusions This study represents the first report on the development of a new and efficient process to convert waste cooking oil into d -limonene and l -limonene by exploiting metabolically engineered Y. lipolytica strains for fermentation. The results obtained in this study lay the foundation for more future applications of Y. lipolytica in converting waste cooking oil into various industrially valuable products.
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JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2019
·Vol. 30
·期 20
·18617-18625
·
IF 2.195
Meng Zuchao,Li Mao,Liu Xiang,Lei Zigang
A new hydrazine electrochemical sensor was fabricated based on in situ synthesis of Cu 3 (BTC) 2 /GO nanocomposite. Cu 3 (BTC) 2 /GO composite were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier transform infrared spectrometry (FT-IR). Meanwhile, the electrochemical behaviors of hydrazine on the Cu 3 (BTC) 2 /GO/GCE were studied by cyclic voltammetry and linear sweep voltammetry. Under the optimized conditions, Cu 3 (BTC) 2 /GO/GCE had enhanced electrocatalytic activity toward hydrazine due to synergic catalytic effect between Cu 3 (BTC) 2 and GO. The electrochemical sensor exhibited a wider linear range (1.0 µM to 5000 µM) and a lower detection limit (0.5 μM) as well as good reproducibility and stability. The proposed sensor has also been used for the determination of hydrazine in tap water with satisfactory results.
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Journal of Biological Engineering
·
2020
·Vol. 14
·期 1
·1-13
·
IF 3.429
Liu Qingxiu,Zhang Wei,Chen Siying,Zhuang Zhenjing,Zhang Yi,Jiang Lingli,LIN Jun Sheng
Background Aptamers, single-stranded DNAs or RNAs, can be selected from a library containing random sequences using a method called Systematic Evolution of Ligands by EXponential Enrichment (SELEX). In SELEX, monitoring the enriching statuses of aptamer candidates during the process is a key step until today. Conformational change of an aptamer caused by target-binding in gel can be used to indicate its statuses of binding. Results In this study, an easy-to-implement gel-based diffusion method (GBDM) was developed to monitor the interaction between enriched aptamer candidates and their targets. In order to prove the concept, characterization of aptamers targeting their targets including protein (thrombin) and non-protein molecules (acetamiprid, ATP, atrazine, profenofos and roxithromycin), respectively, were performed using mini gels. Our method has advantages over the common methods including easy performed with labor- and time- saving in experimental operation. The concept has been proven by monitoring enrichment of dynamic aptamer candidate libraries targeting a small molecule 2,2-bis(4-chlorophenyl) acetic acid (DDA) during SELEX process. A mini gel cassette was designed and fabricated by our laboratory to make mini agarose gels for diffusion with different directions. Conclusions These results indicate that GBDM, in particular, chasing diffusion is suitable for monitoring the interaction between enriched aptamer candidates and their targets. These pioneering efforts are helpful for novel aptamer selection by breaking through the technical bottleneck of aptamer development and helpful for development of novel aptasensors.
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MICROCHIMICA ACTA
·
2019
·Vol. 186
·期 12
·1-10
·
IF 5.479
Dong Nan,Zhang Lingxue,Yao Jianmei,Ma Peijian,He Jing,Li Tao,Wang Yuan
A detailed study has been carried out on monohydroxycucurbit[7]uril-based stir-bar sorptive extraction (SBSE). A polydimethylsiloxane coating was produced by a sol–gel technique and doped with monohydroxycucurbit[7]uril ((HO) 1 Q [7]) as a selective sorbent phase. (HO) 1 Q [7] was chemically bound to the sol–gel silica substrate through hydrolysis and polycondensation. The coating possesses a porous surface, shows strong solvent resistance and good thermal stability, and has a long lifespan. Four groups of compounds, with polarities ranging from apolar polycyclic aromatic hydrocarbons to polar ketones, aromatic amines and phenols, were selected as test analytes. They were extracted with the coated stir bar, then desorbed with methanol and quantified by high-performance liquid chromatography with ultraviolet detection. The limits of detection range between 1.3 and 15 μg L −1 , the linear ranges extend from 5 to 10,000 μg L −1 , and the relative recoveries from spiked samples range between 76.4 and 97.9%. The intraday relative standard deviations range from 2.3 to 8.6% (for n = 3, at 500 μg L −1 ). Compared with a commercial PDMS-coated stir bar and a polyether sulfone-coated stir bar, the new stir bar shows wider applicability and better extraction efficiency for each group of compounds. In addition, the stir bar can simultaneously extract mixtures of chemicals of different polarities. This endows it with the potential for recovering a broad group of polar organic compounds.
A stir bar for sorptive extraction based on monohydroxycucurbit[7]uril has been prepared by a sol–gel technique. The stir bar coupled with HPLC with UV detection allows for the determination of a variety of polar compounds and multicomponent mixtures, respectively.
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