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Table of Content
28 July 2018, Volume 26 Issue 7
    Separation Science and Engineering
    Degradation and mineralization of aniline by O3/Fenton process enhanced using high-gravity technology
    Yuejiao Qin, Shuai Luo, Shuo Geng, Weizhou Jiao, Youzhi Liu
    2018, 26(7):  1444-1450.  doi:10.1016/j.cjche.2018.01.018
    Abstract ( 662 )   PDF (935KB) ( 48 )  
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    The degradation and mineralization of aniline (AN) using ozone combined with Fenton reagent (O3/Fenton) in a rotating packed bed (RPB) was proposed in this study, and the process (RPB-O3/Fenton) was compared with conventional O3/Fenton in a stirred tank reactor (STR-O3/Fenton) or single ozonation in an RPB (RPB-O3). Effects of high gravity factor, H2O2 dosage, H2O2 dosing method and initial pH on the AN mineralization efficiency were investigated in the RPB-O3/Fenton process. In addition, the behavior of Fe(Ⅱ) was monitored at different H2O2 dosing methods and pH values. Finally, the optimal operation conditions were determined with high gravity factor of 100, initial pH of 5, Fe(Ⅱ) concentration of 0.8 mmol·L-1 and H2O2 dosage of 2.5 ml. Under these conditions, for aniline wastewater at the volume of 1 L and concentration of 200 mg·L-1, a fast and thorough decay of AN was conducted in 10 min, and the TOC removal efficiency reached 89% in 60 min. The main intermediates of p-benzoquinone, nitrobenzene, maleic acid and oxalic acid were identified by liquid chromatography/mass spectroscopy (LC/MS), and the degradation pathways of AN in RPB-O3/Fenton system were proposed based on experimental evidence. It could be envisioned that high-gravity technology combined with O3/Fenton processes would be promising in the rapid and efficient mineralization of wastewater.
    Three-liquid-phase extraction and separation of V(V) and Cr(VI) from acidic leach solutions of high-chromium vanadium-titanium magnetite
    Pan Sun, Kun Huang, Xiaoqin Wang, Na Sui, Jieyuan Lin, Wenjuan Cao, Huizhou Liu
    2018, 26(7):  1451-1457.  doi:10.1016/j.cjche.2018.01.023
    Abstract ( 614 )   PDF (522KB) ( 63 )  
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    A new method by liquid-liquid-liquid three phase system, consisting of acidified primary amine N1923 (abbreviated as A-N1923), poly(ethylene glycol) (PEG) and (NH4)2SO4 aqueous solution, was suggested for the separation and simultaneous extraction of V(V) and Cr(VI) from the acidic leach solutions of highchromium vanadium-titanium magnetite. Experimental results indicated that V(V) and Cr(VI) could be selectively enriched into the A-N1923 organic top phase and PEG-rich middle phase, respectively, while Al(Ⅲ) and other co-existing impurity ions, such as Si(IV), Fe(Ⅲ), Ti(IV), Mg(Ⅱ) and Ca(Ⅱ) in acidic leach solutions, could be enriched in the (NH4)2SO4 bottom aqueous phase. During the process for extraction and separation of V(V) and Cr(VI), almost all of impurity ions could be removed. The separation factors between V (V) and Cr(VI) could reach 630 and 908, respectively in the organic top phase and PEG middle phase, and yields of recovered V(V) and Cr(VI) in the top phase and middle phase respectively were all above 90%. Various effects including aqueous pH, A-N1923 concentration, PEG added amount and (NH4)2SO4 concentration on three-phase partitioning of V(V) and Cr(VI) were discussed. It was found that the partition of Cr(VI) into the PEG-rich middle phase was driven by hydrophobic interaction, while extraction of V(V) by A-N1923 resulted of anion exchange between NO3- and H2V10O284-. Stripping of V(V) and Cr(VI) from the top organic phase and the middle PEG-rich phase were achieved by mixing respectively with NaNO3 aqueous solutions and NaOH-(NH4)2SO4 solutions. The present work highlights a new approach for the extraction and purification of V and Cr from the complex multi-metal co-existing acidic leach solutions of high-chromium vanadium-titanium magnetite.
    Insight into the degradation mechanism of cefixime under crystallization condition
    Lingyu Wang, Xiaona Li, Yumin Liu, Dandan Han, Shiyuan Liu, Teng Zhang, Bo Yu, Junbo Gong
    2018, 26(7):  1458-1467.  doi:10.1016/j.cjche.2018.01.012
    Abstract ( 1123 )   PDF (648KB) ( 176 )  
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    The chemical stability of cefixime was determined by high-performance liquid chromatography (HPLC) under different conditions, including factors such as pH, solvents, initial concentration, temperature and additives. The degradation process follows the first-order kinetics. A pH-rate profile exhibits the U-shape and shows the maximum stability of cefixime at pH=6. The stability in different pure solvents is ranked as acetone N ethanol N methanol N water, while the degradation rate of cefixime exists a maximum at the ratio of 0.6 in water + methanol mixtures. In addition, the degradation rate increases with the temperature increasing and the activation energy of degradation was found to be 27.078 kJ·mol-1 in acetone + water mixed solvents. The addition of different additives was proven to either inhibit or accelerate the degradation. The degradation products were analyzed using HPLC, LC-MS and infrared spectroscopy, and the possible degradation pathways in acid as well as alkaline environment were proposed to help us understand the degradation behavior of cefixime.
    Experimental and simulation of the reactive dividing wall column based on ethyl acetate synthesis
    Jiangwei Xie, Chunli Li, Fei Peng, Lihui Dong, Shuaiming Ma
    2018, 26(7):  1468-1476.  doi:10.1016/j.cjche.2018.01.021
    Abstract ( 716 )   PDF (877KB) ( 62 )  
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    Reactive dividing wall column (RDWC) is a highly integrated unit which combines reaction distillation (RD) with dividing wall column separation technology into one shell, and it realized the chemical reaction and the separation of multiple product fractions simultaneously. In this paper, the reaction of esterification with acetic acid and ethanol to produce ethyl acetate was used as the research system, experiments and simulations of the RDWC were carried out. This system in the traditional process mostly used the homogeneous catalyst (e.g. sulfuric acid). However, in view of the corrosion of the equipment caused by the acidity of the catalyst, we used the heterogeneous catalysts - iron exchange resins - Amberlyst15 and proposed a novel catalyst loading method. Firstly, the reliability of the model of the simulation was verified by the experimental study on the change of liquid split ratio and reflux ratio. After that, the four-column model was established in Aspen Plus to analyze the effects of the amount of azeotropic agent, reflux ratio and acetic acid concentration. Finally, for a fair comparison, the economic analysis was conducted between traditional RD column and RDWC. The results showed that RDWC can save 34.7% of total operating costs and 18.5% of TAC.
    Modeling investigation of geometric size effect on pervaporation dehydration through scaled-up hollow fiber NaA zeolite membranes
    Jiacheng Wang, Peng Ye, Xuechao Gao, Yuting Zhang, Xuehong Gu
    2018, 26(7):  1477-1484.  doi:10.1016/j.cjche.2018.01.027
    Abstract ( 637 )   PDF (681KB) ( 32 )  
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    A mass transfer model in consideration of multi-layer resistances through NaA zeolite membrane and lumen pressure drop in the permeate side was developed to describe pervaporation dehydration through scaled-up hollow fiber supported NaA zeolite membrane. It was found that the transfer resistance in the lumen of the permeate side is strongly related with geometric size of hollow fiber zeolite membrane, which could not be neglected. The effect of geometric size on pervaporation dehydration could be more significant under higher vacuum pressure in the permeate side. The transfer resistance in the lumen increases with the hollow fiber length but decreases with lumen diameter. The geometric structure could be optimized in terms of the ratio of lumen diameter to membrane length. A critical value of dI/L (Rc) to achieve high permeation flux was empirically correlated with extraction pressure in the permeate side. Typically, for a hollow fiber supported NaA zeolite membrane with length of 0.40 m, the lumen diameter should be larger than 2.0 mm under the extraction pressure of 1500 Pa.
    Understanding the influence of microwave on the relative volatility used in the pyrolysis of Indonesia oil sands
    Hong Li, Peng Shi, Xiaolei Fan, Xin Gao
    2018, 26(7):  1485-1492.  doi:10.1016/j.cjche.2018.02.035
    Abstract ( 477 )   PDF (1982KB) ( 41 )  
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    In this paper, pyrolysis of Indonesian oil sands (IOS) was investigated by two different heating methods to develop a better understanding of the microwave-assisted pyrolysis. Thermogravimetric analysis was conducted to study the thermal decomposition behaviors of IOS, showing that 550℃ might be the pyrolysis final temperature. A explanation of the heat-mass transfer process was presented to demonstrate the influence of microwave-assisted pyrolysis on the liquid product distribution. The heat-mass transfer model was also useful to explain the increase of liquid product yield and heavy component content at the same heating rate by two different heating methods. Experiments were carried out using a fixed bed reactor with and without the microwave irradiation. The results showed that liquid product yield was increased during microwave induced pyrolysis, while the formation of gas and solid residue was reduced in comparison with the conventional pyrolysis. Moreover, the liquid product characterization by elemental analysis and GC-MS indicated the significant effect on the liquid chemical composition by microwave irradiation. High polarity substances (ε < 10 at 25℃), such as oxyorganics were increased, while relatively low polarity substances (ε > 2 at 25℃), such as aliphatic hydrocarbons were decreased, suggesting that microwave enhanced the relative volatility of high polarity substances. The yield improvement and compositional variations in the liquid product promoted by the microwave-assisted pyrolysis deserve the further exploitation in the future.
    Catalysis, kinetics and reaction engineering
    Selective aerobic oxidation of p-cresol with co-catalysts between metalloporphyrins and metal salts
    Yuanbin She, Yao Fan, Lei Zhang, Ying Xu, Min Yu, Haiyan Fu
    2018, 26(7):  1493-1498.  doi:10.1016/j.cjche.2018.01.015
    Abstract ( 621 )   PDF (1551KB) ( 68 )  
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    A green and efficient method for the selective aerobic oxidation of p-cresol to p-hydroxybenzaldehyde catalyzed by co-catalysts between metalloporphyrins and metal salts was investigated and developed. The relationship between the synergistic catalytic effects and the composition as well as amount of co-catalysts was investigated. Moreover, the influence of different reaction conditions was studied in details. A high p-cresol conversion (>99%) and p-hydroxybenzaldehyde selectivity (83%) were obtained using only 1.125×10-5 mol T(p-CH3O)PPFeCl-Co(OAc)2 used under mild, optimized reaction conditions. A possible mechanism for the reaction was also proposed. This work would be meaningful and instructive for the further researches and applications of co-catalyst system on oxidation of cresols and could give some enlightenment on the selectively catalytic oxidation of the side-chain alkyls of aromatics.
    Optimal reaction conditions for pyridine synthesis in riser reactor
    Shuaishuai Zhou, Zelong Liu, Xiao Yan, Qin Di, Mengxi Liu, Chunxi Lu, Guangzhou Jin
    2018, 26(7):  1499-1507.  doi:10.1016/j.cjche.2018.01.020
    Abstract ( 687 )   PDF (829KB) ( 32 )  
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    Pyridine has been generally synthesized by aldehydes and ammonia in a turbulent fluidized-bed reactor. In this paper, a novel riser reactor was proposed for pyridine synthesis. Experiment result showed that the yield of pyridine and 3-picoline decreased, but the selectivity of pyridine over 3-picoline increased compared to turbulent fluidized-bed reactor. Based on experimental data, a modified kinetic model was used for the determination of optimal operating condition for riser reactor. The optimal operating condition of riser reactor given by this modified model was as follows:The reaction temperature of 755 K, catalyst to feedstock ratio (CTFR) of 87, residence time of 3.8 s and initial acetaldehydes concentration of 0.0029 mol·L-1 (acetaldehydes to formaldehydes ratio by mole (ATFR) of 0.65 and ammonia to aldehydes ratio by mole (ATAR) of 0.9, water contention of 63wt% (formaldehyde solution)).
    Desulfurization of liquid hydrocarbon fuels via Cu2O catalyzed photo-oxidation coupled with liquid-liquid extraction
    Xiaoming Gao, Jiao Fei, Yanyan Shang, Feng Fu
    2018, 26(7):  1508-1512.  doi:10.1016/j.cjche.2018.01.022
    Abstract ( 577 )   PDF (986KB) ( 24 )  
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    By combining the photochemical reaction and liquid-liquid extraction (PODS), we studied desulfurization of model fuel and FCC gasoline. The effects of air flow, illumination time, extractants, volume ratios of extractant/fuel, and catalyst amounts on the desulfurization process of PODS were analyzed in detail. Under the conditions with the air as oxidant (150 ml·min-1), the mixture of DMF-water as extractant (the volume ratio of extractant/oil of 0.5) and photo-irradiation time of 2 h, the sulfur removal rate reached only 42.63% and 39.54% for the model and FCC gasoline, respectively. Under the same conditions, the sulfur removal rate increased significantly up to 79% for gasoline in the presence of Cu2O catalyst (2 g·L-1). The results suggest that the PODS combined with a Cu2O catalyst seems to be a promising alternative for sulfur removal of gasoline.
    Chemical Engineering Thermodynamics
    Densities and surface tensions of ionic liquids/sulfuric acid binary mixtures
    Tao Zhang, Jing Hu, Shengwei Tang
    2018, 26(7):  1513-1521.  doi:10.1016/j.cjche.2018.02.001
    Abstract ( 804 )   PDF (2025KB) ( 42 )  
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    The densities and surface tensions of[Bmim] [TFO]/H2SO4,[Hmim] [TFO]/H2SO4 and[Omim] [TFO]/H2SO4 binary mixtures were measured by pycnometer and Wilhelmy plate method respectively. The results show that densities and surface tensions of the mixtures decreased monotonously with increasing temperatures and increasing ionic liquid (IL) molar fraction. IL with longer alkyl side-chain length brings a lower density and a smaller surface tension to the ILs/H2SO4 binary mixtures. The densities and surface tensions of the mixtures are fitted well by Jouyban-Acree (JAM) model and LWW model respectively. Redlich-Kister (R-K) equation and modified Redlich-Kister (R-K) equation describe the excess molar volumes and excess surface tensions of the mixtures well respectively. Adding a small amount of ILs (χIL < 0.1) into sulfuric acid brings an obvious decrease to the density and the surface tension. The results imply that the densities and surface tensions of ILs/H2SO4 binary mixtures can be modulated by changing the IL dosage or tailoring the IL structure.
    Energy, Resources and Environmental Technology
    Dissolution-regrowth synthesis of SiO2 nanoplates and embedment into two carbon shells for enhanced lithium-ion storage
    Zhijun Yan, Xiangcun Li, Xiaobin Jiang, Le Zhang, Yan Dai, Gaohong He
    2018, 26(7):  1522-1527.  doi:10.1016/j.cjche.2018.01.016
    Abstract ( 662 )   PDF (754KB) ( 23 )  
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    In this work, SiO2 nanoplates with opened macroporous structure on carbon layer (C-mSiO2) have been obtained by dissolving and subsequent regrowing the outer solid SiO2 layer of the aerosol-based C-SiO2 double-shell hollow spheres. Subsequently, triple-shell C-mSiO2-C hollow spheres were successfully prepared after coating the CmSiO2 templates by the carbon layer from the carbonization of sucrose. When being applied as the anode material for lithium-ion batteries, the C-mSiO2-C triple-shell hollow spheres deliver a high capacity of 501 mA·h·g-1 after 100 cycles at 500 mA·g-1 (based on the total mass of silica and the two carbon shells), which is higher than those of C-mSiO2 (391 mA·h·g-1) spheres with an outer porous SiO2 layer, C-SiO2-C (370 mA·h·g-1) hollow spheres with a middle solid SiO2 layer, and C-SiO2 (319.8 mA·h·g-1) spheres with an outer solid SiO2 layer. In addition, the battery still delivers a high capacity of 403 mA·h·g-1 at a current density of 1000 mA·g-1 after 400 cycles. The good electrochemical performance can be attributed to the high surface area (246.7 m2·g-1) and pore volume (0.441 cm3·g-1) of the anode materials, as well as the unique structure of the outer and inner carbon layer which not only enhances electrical conductivity, structural stability, but buffers volume change of the intermediate SiO2 layer during repeated charge-discharge processes. Furthermore, the SiO2 nanoplates with opened macroporous structure facilitate the electrolyte transport and electrochemical reaction.
    Distinct synergetic effects in the ozone enhanced photocatalytic degradation of phenol and oxalic acid with Fe3+/TiO2 catalyst
    Yongbing Xie, Yingying Chen, Jin Yang, Chenming Liu, He Zhao, Hongbin Cao
    2018, 26(7):  1528-1535.  doi:10.1016/j.cjche.2018.01.017
    Abstract ( 674 )   PDF (660KB) ( 20 )  
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    In this work, phenol and oxalic acid (OA) degradation in an ozone and photocatalysis integrated process was intensively conducted with Fe3+/TiO2 catalyst. The ferrioxalate complex formed between Fe3+ and oxalate accelerated the removal of OA in the ozonation, photolysis and photocatalytic ozonation process, for its high reactivity with ozone and UV. Phenol was degraded in ozonation and photolysis with limited TOC removal rates, but much higher TOC removal was achieved in photocatalytic ozonation due to the generation of·OH. The sequence of UV light and ozone in the sequential process also influences the TOC removal, and ozone is very powerful to oxidize intermediates catechol and hydroquinone to maleic acid. Fenton or photo-Fenton reactions only played a small part in Fe3+/TiO2 catalyzed processes, because Fe3+ was greatly reduced but not regenerated in many cases. The synergetic effect was found to be highly related with the property of the target pollutants. Fe3+/TiO2 catalyzed system showed the highest ability to destroy organics, but the TiO2 catalyzed system showed little higher synergy.
    A study on simultaneous removal of NO and SO2 by using sodium persulfate aqueous scrubbing
    Xue Kang, Xiaoxun Ma, Jian'an Yin, Xuchun Gao
    2018, 26(7):  1536-1544.  doi:10.1016/j.cjche.2018.02.026
    Abstract ( 567 )   PDF (3879KB) ( 27 )  
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    Nitric oxide (NO) removal and sulfur dioxide (SO2) removal by sodium persulfate (Na2S2O8) were studied in a Bubble Column Reactor. The proposed reaction pathways of NO and SO2 removal are discussed. The effects of temperatures (35-90℃), Na2S2O8 (0.05-0.5 mol·L-1), FeSO4 (0.5-5.0 m mol·L-1) and H2O2 (0.25 mol·L-1) on NO and SO2 removal were investigated. The results indicated that increased persulfate concentration led to increase in NO removal at various temperatures. SO2 was almost completely removed in the temperature range of 55-85℃. Fe2+ accelerated persulfate activation and enhanced NO removal efficiency. At 0.2 mol·L-1 Na2S2O8 and 0.5-1.0 mmol·L-1 Fe2+, NO removal of 93.5%-99% was obtained at 75-90℃, SO2 removal was higher than 99% at all temperatures. The addition of 0.25 mol·L-1 H2O2 into 0.2 mol·L-1 Na2S2O8 solution promoted NO removal efficiency apparently until utterly decomposition of H2O2, the SO2 removal was as high as 98.4% separately at 35℃ and 80℃.
    Experimental study on the effects of drying methods on the stabilities of lignite
    Yixin Zhang, Jixiang Dong, Fanhui Guo, Xiaokai Chen, Jianjun Wu, Zhenyong Miao
    2018, 26(7):  1545-1554.  doi:10.1016/j.cjche.2018.05.012
    Abstract ( 571 )   PDF (1573KB) ( 37 )  
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    The drying processes are always applied prior to the transportation or utilization of lignite, and result in notable changes in the stabilities of lignite. In this paper, the study on the effects of nitrogen and MTE drying process on the physico-chemical properties and stabilities of Zhaotong lignite was carried out. The briquettes produced by MTE drying in this study were 150 mm in dimension, and so had a much larger particle size than nitrogendried samples. Nitrogen adsorption, mercury intrusion porosimetry and scanning electron microscopy all suggested that drying was accompanied by the transformation of larger pores into smaller ones. Compared to nitrogen drying, the pore structures could be stabilized by the MTE process. The soluble salts were removed during MTE drying which resulted in the decrease in ash and the concentrations of some of the major metals. The removal of water enhanced the hydrophilicity of nitrogen dried samples, but did not affect the hydrophilicity of MTE dried samples. The moisture holding capacity of MTE dried samples reduced faster than nitrogen dried samples with the decrease of residual moisture content. The moisture readsorption processes of MTE dried samples were strongly inhibited due to the much larger particle size of sample produced by MTE drying than nitrogen drying. The susceptibility to spontaneous combustion, indicated by cross point temperature and self-heating tests, of nitrogen and MTE dried samples increased with the decrease of residual moisture content. The MTE dried samples are more liable to spontaneous combustion than nitrogen dried samples with the same residual moisture and particle size. However, the larger particle size of the MTE product made it more stable with respect to spontaneous combustion and also moisture readsorption.
    Degradation analysis of A2/O combined with AgNO3 + K2FeO4 on coking wastewater
    Pengyu Zhu, Kaijin Zhu, Rob Puzey, Xiaoli Ren
    2018, 26(7):  1555-1560.  doi:10.1016/j.cjche.2018.02.003
    Abstract ( 629 )   PDF (832KB) ( 64 )  
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    In this work, a coking wastewater was selected and a biochemical A2/O treatment device for fractional degradation was designed and employed. After each stage of the treatment, the products were analyzed through gas chromatography-mass spectroscopy (GC-MS) to determine their composition. Finally, AgNO3 + K2FeO4 was used as an advanced deep catalytic oxidation treatment. It was concluded from the analysis that cyclic organics could be degraded and the chemical oxygen demand (COD) was controlled within 50 mg·L-1, in line with the target value. Meanwhile, the spectra obtained from the GC-MS were in accordance with the conclusions reached based on the COD. The research results showed that all hard-degradable organics in coking wastewater could be eliminated through the A2/O bio-membrane treatment and the advanced treatment of making use of K2FeO4 as an oxidant and Ag+ as a catalyst, the catalytic efficiency with Ag+ as a catalyst of K2FeO4 was very high. Ag+ could evidently improve the oxidation capacity of K2FeO4 to wastewater in its short stability time, and this is an important innovation.
    Materials and Product Engineering
    Hierarchical porous MgBO2(OH) microspheres: Hydrothermal synthesis, thermal decomposition, and application as adsorbents for Congo red removal
    Panpan Sun, Liyuan Chen, Lin Xu, Wancheng Zhu
    2018, 26(7):  1561-1569.  doi:10.1016/j.cjche.2018.01.013
    Abstract ( 628 )   PDF (2604KB) ( 33 )  
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    A facile eco-friendly hydrothermal route (180℃, 12.0 h) has been developed for the first time to the uniform hierarchical porous MgBO2(OH) microspheres without the aid of any organic additive, surfactant or template, by using the abundant MgCl2·6H2O, H3BO3 and NaOH as the raw materials. The as-obtained porous microspheres exhibit a specific surface area of 94.752 mg·g-1, pore volume of 0.814 cm3·g-1, and ca. 84.0% of which have a diameter of 2.25-3.40 μm. The thermal decomposition of the porous MgBO2(OH) microspheres (650℃, 2.5℃·min-1) leads to the porous Mg2B2O5 microspheres with well-retained morphology. When utilized as the adsorbents for the removal of CR from mimic waste water, the present porous MgBO2(OH) microspheres exhibit satisfactory adsorption capacity, with the maximum adsorption capacity qm of 309.1 mg·g-1, much higher than that derived from most of the referenced adsorbents. This opens a new window for the facile green hydrothermal synthesis of the hierarchical porous MgBO2(OH) microspheres, and extends the potential application of the 3D hierarchical porous metal borates as high-efficiency adsorbents for organic dyes removal.
    On the database-based strategy of candidate extractant generation for de-phenol process in coking wastewater treatment
    Ran Xu, Yuehong Zhao, Qingzhen Han, Xinyu Liu, Hongbin Cao, Hao Wen
    2018, 26(7):  1570-1580.  doi:10.1016/j.cjche.2018.01.014
    Abstract ( 534 )   PDF (783KB) ( 51 )  
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    A database-based strategy of candidate generation was proposed for molecular design of new de-phenol extractants following the idea of finding new applications of existing commercial compounds. The strategy has the advantage that the environmental, safety and health risks of candidate compounds are known and controllable. In this work, the Existing Commercial Compounds (ECC) database and special combined search strategy were developed as the base for the proposed CAMD method following such idea, and molecules for phenol extraction used in coking wastewater treatment were selected from the ECC database. The candidate solvents cover the following categories:ketones, esters, ethers, alcohols, anhydrides and benzene compounds, which are consistent with the de-phenol extractants commonly used in the industry or experiment. The compounds with higher partition coefficient and selectivity than widely used methyl isobutyl ketone (MIBK) are mainly ketones. 26 obtained molecules show higher partition coefficient and selectivity than MIBK, which are suggested to be further investigated by experiment. Furthermore, analysis of these potential molecules may present the effective functional groups as the initial group set to generate new molecular structures of de-phenol extractants. The results show that the proposed method enables us to efficiently generate chemicals with benefits of less time, less economical cost, and known environmental impact as well.
    DNA-assisted rational design of BaF2 linear and erythrocyte-shaped nanocrystals
    Xinmei Zhao, Huanhuan You, Faming Gao
    2018, 26(7):  1581-1585.  doi:10.1016/j.cjche.2018.01.019
    Abstract ( 552 )   PDF (786KB) ( 26 )  
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    The synthesis of inorganic materials with special morphologies with the assistance of biological molecules is a potential development in the field of controllable growth and assembly of nanomaterials. In this paper, BaF2 nanocrystals in patterns of well-defined linear and erythrocyte-shaped structure were synthesized with the assistance of Escherichia coli DNA. Morphology and the arrangement of BaF2 particles on DNA were controllable by altering the reaction condition. Square nanoparticles arranged in linear chains were gained with the assistance of normal DNA; while, erythrocyte-shaped BaF2 nanospheres were synthesized with the assistance of denatured DNA. Besides, the influences of solvent, reaction temperature, concentration of reactants and the heating time on the morphology of the BaF2 particles were studied.
    Preparation of vapreotide-templated silver nanocages and their photothermal therapy efficacy
    Ruiyan Zhu, Yanji Li, Kexin Bian, Zhengrong Gao, Dawei Gao
    2018, 26(7):  1586-1590.  doi:10.1016/j.cjche.2018.01.026
    Abstract ( 674 )   PDF (551KB) ( 16 )  
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    Vapreotide acetate (Vap) was used as a biotemplate to synthesize silver nanocages through direct co-incubation of a AgNO3 solution, following by reduction using fresh NaBH4. The characterized vapreotide-templated silver nanocages (Vap-AgNCs) presented a wide and red shifted absorption band with a maximum between 480 nm and 800 nm and possessed a uniform structure with a face-centered cubic crystal structure. The biocompatibility of Vap-AgNCs was assessed using the MTT method, indicating Vap-AgNCs had better biocompatibility when its concentration was lower than 2.5×10-4 mmol·L-1. The photothermal characteristics of Vap-AgNCs were analyzed with laser irradiation (808 nm, 1.5 W·cm-2) and the results showed that the temperature of the VapAgNCs solution reached 45℃ starting from 25℃ within 5 min. Additionally, Vap-AgNCs with a laser led to HeLa cell death. Therefore, the prepared Vap-AgNCs is expected to be an effective photothermal therapy agent.
    High efficiency production of ginsenoside compound K by catalyzing ginsenoside Rb1 using snailase
    Zhiguang Duan, Chenhui Zhu, Jingjing Shi, Daidi Fan, Jianjun Deng, Rongzhan Fu, Rong Huang, Cuiying Fan
    2018, 26(7):  1591-1597.  doi:10.1016/j.cjche.2018.02.004
    Abstract ( 679 )   PDF (620KB) ( 36 )  
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    The rare ginsenoside Compound K (C-K) is attracting more attention because of its good physiological activity and urgent need. There are many pathways to obtain ginsenoside C-K, including chemical and biological methods. Among these, the conversion of PPD-type ginsenosides by enzymatic hydrolysis is a trend due to its high efficiency and mild conditions. For effectively extracting from the other panaxadiol saponins, the conversion process for ginsenoside C-K was investigated using snailases in this study. The univariate experimental design and response surface methodology were used to determine the optimal hydrolysis conditions for the conversion of ginsenoside Rb1 into ginsenoside C-K by snailases. The optimum conditions were as follows:pH 5.12, temperature 51℃, ratio of snailase/substrate 0.21, and reaction time 48 h. On the basis of these parameters, the addition of 1.0 mmol·L-1 ferric ion was found to significantly improve the enzymolysis of snailases for the first time. With the above conditions, the maximum conversion rate reached 89.7%, suggesting that the process can obviously increase the yield of ginsenoside C-K. The bioassay tests indicated that the ginsenoside C-K showed anti-tumor activity in a series of tumor cell lines. Based on these results, we can conclude that the process of rare ginsenoside CK production by enzymolysis with snailase is feasible, efficient, and suitable for the industrial production and application.