SEPARATION SCIENCE AND TECHNOLOGY
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2019
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IF 1.354
Chenhua Shu,Lina Wang,Peijun Kong,Meizhu Gao
A poly ionic liquid, poly(1-vinyl imidazole)-p-xylylene dichloride (PVIm-PXDC), was synthesized and used for fuel oil denitrogenation. The structure of PVIm-PXDC was characterized and the denitrogenation performance was investigated. Results indicate that the pseudo-second-order kinetic model and Langmuir model are appropriate to describe the adsorption kinetics and thermodynamics, respectively. The adsorption ability of PVIm-PXDC for different nitrogen compounds follows the order of indole > pyrrole > quinoline > pyridine. The equilibrium adsorption amount decreased about 10% for all the nitrogen compounds after six regeneration cycles and the denitrogenation and regeneration processes have no influence on the structure of PVIm-PXDC.
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CONSTRUCTION AND BUILDING MATERIALS
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2019
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IF 4.046
Bo Liang,Kai Shi,Yanfang Niu,Zhengchun Liu,Jianlong Zheng
Styrene-butadiene-styrene (SBS)-modified asphalt plays an integral role in asphalt pavements. To facilitate the understanding of the correlations between the physical and chemical properties of asphalt cement and SBS , a method for the direct quantitative determination of the SBS modification mechanism via potentiometric titration is proposed. This method will theoretically guide the processing design of SBS-modified asphalts. Potentiometric titration is applied to investigate the unsaturation of SBS-mixed, SBS-modified, and SBS/sulfur-modified asphalts with different SBS dosages ranging from 0% to 10%. The unsaturation of SBS-mixed asphalt exhibits a good linear increase with an increase in SBS dosage. A noticeable loss of SBS unsaturation occurs in SBS- and SBS/sulfur-modified asphalts after undergoing complete modification. In addition, unsaturation presents an evident inflection point at approximately 5 wt% SBS with an increase in SBS dosage. This finding indicates SBS changing from a dispersed phase to a continuous phase in the modified asphalts. Remarkably, the addition of sulfur can accelerate the emergence of an inflection point. Results corroborate that various types of virgin asphalt exhibit different inflection points. SBS/sulfur-modified asphalt demonstrates stronger chemical cross-linking than SBS-modified asphalt. These findings are further confirmed via fluorescence imaging, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. Potentiometric titration potentially provides a direct quantitative method for probing the modification mechanism of and designing customized processing for SBS-modified asphalts.
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Journal of Materials Chemistry A
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2019
·Vol. 7
·期 44
·25641-25649
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IF 10.733
Jinqiu Yuan,Mengyuan Wu,Hong Wu,Yanan Liu,Xinda You,Runnan Zhang,Yanlei Su,Hao Yang,Jianliang Shen,Zhongyi Jiang
The demand for thin-film composite nanofiltration membranes bearing unprecedented water permeance and desirable salt rejection is ever increasing in desalination. Conventional interfacial polymerization usually generates a thick (∼100 nm) skin layer on hydrophobic substrate having low-porosity, leading to limited water permeance. Herein, we engineered a highly porous and superhydrophilic composite substrate to modulate the interfacial polymerization and generate an ultrathin polyamide skin layer, even below 10 nm. The composite substrate was constructed by depositing covalent organic framework nanosheets (CONs) on a microfiltration membrane via vacuum-assistant assembly. Owing to the highly porous structure and superhydrophilic nature of CONs, the composite substrate favored a high storage capacity and uniform distribution of the amine monomers. We manipulated the monomer storage capacity of the substrate by varying the loading content of CONs and demonstrated that higher amino monomer concentration could accelerate the self-sealing and self-termination of the interfacial polymerization, thus generating a thinner skin layer from ∼70 nm to sub-10 nm. Moreover, the highly porous structure of CONs imparted little additional water transport resistance. The sub-10 nm film composite membrane exhibited a superior water permeance of 535.5 L m−2 h−1 MPa−1 with a high rejection of 94.3% for Na2SO4, which was about 2–8 times higher than that of state-of-the-art nanofiltration membranes with comparable rejection.
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POLYMERS FOR ADVANCED TECHNOLOGIES
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2019
·Vol. 31
·期 4
·807-816
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IF 2.162
Chun-Hui Du,Xin-Yi Zhang,Chun-Jin Wu
Chitosan (CS) with good hydrophilicity and charged property was used to modify graphene oxide (GO), the obtained GO-CS was used as a novel modifier to fabricate thin film composite forward osmosis (FO) membranes. The results revealed that the amino groups on CS reacted with carboxyl groups on GO, and the lamellar structure of the GO nanosheets was peeled off by CS, resulting in the reducing of their thicknesses. The GO-CS improved the hydrophilicity of polyethersulfone (PES) substrate, and their contact angles decreased to 64° with the addition of GO-CS in the substrate. GO-CS also increased the porosity of the substrate and surface roughness of FO membrane, thereby optimizing the water flux and reverse salt flux of FO membrane. The average water flux of the FO membrane reached the optimal flux of 21.34 L/(m 2 h) when GO-CS addition was 0.5 wt%, and further addition of GO-CS to the substrate would decrease the water flux of FO membrane, and the reverse salt flux also decreased to the lowest value of 2.26 g/(m 2 h). However, the salt rejection of the membrane increased from 91.4% to 95.1% when GO-CS addition increased from 0.5 to 1.0 wt% under FO mode using 1 mol/L sodium chloride (NaCl) solution as draw solution (DS). In addition, high osmotic pressure favored water permeation, and at the same concentration of DS, magnesium chloride (MgCl 2 ) exhibited better properties than NaCl. These results all suggested that GO-CS was a good modifier to fabricate FO membrane, and MgCl 2 was a good DS candidate.
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CHEMICAL ENGINEERING JOURNAL
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2018
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IF 6.735
Xiao-hui Wei,Chao Li,Chunlai Wang,Song Lin,Jinhui Wu,Min-jie Guo
Hierarchical organic-inorganic nanocomposites derived from polyethersulfone (PES) nanofibrous membranes with a post-modification of dopamine (DA) and polyethylenimine (PEI), comprising a high content (33 wt%) of MgO nanoparticles of smaller dimensions (12.7 ± 3.0 nm), were successively fabricated using electrospinning and DA/PEI self-polymerization methods. The obtained hybrid membranes have a rapid capture and great destructive capacity towards paraoxon-ethyl toxin degradation with a relatively short interaction time (up to 92% within 40 min) for effective environmental remediation.
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JOURNAL OF CHROMATOGRAPHY A
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2018
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IF 3.716
Fan Hu,Zhanghui Wang,Baoku Zhu,Liping Zhu,Youyi Xu
Energy-efficient and time-saving process for recovery of hazardous dyes from wastewater is highly desired in dyeing industry. In this work, poly( N -vinyl imidazole) (PVI) gel-filled membrane adsorbers were developed for highly efficient recovery of dyes through adsorption filtration. The membrane adsorbers were fabricated via dip-coating of Nylon macroporous membranes in PVI solutions followed by quaternization crosslinking with p-xylylene dichloride (XDC). Physicochemical characterizations indicated that PVI gel was successfully filled and fixed inside the Nylon matrix. In optimized conditions. The treating capacity of membrane adsorbers to typical dye sunset yellow (25 ppm of the feed concentration) reached up to 197 mg/g with the removal ratio >99%. Both the treating capacity and the removal ratio were kept steady even when the permeation flux was as high as 1000 L/m 2 h. The membrane adsorbers developed in this work were able to not only remove anionic dyes from water, but also separate anionic dyes from cationic ones. The zeta potential and adsorption tests showed that the electrostatic interaction between PVI gel and dye molecules was responsible for the high removal efficiencies to anionic dyes. The membrane adsorbers can be regenerated effectively with NaOH solution and demonstrated good stability in both acidic and alkaline conditions.
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TRANSACTIONS OF TIANJIN UNIVERSITY
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2018
·Vol. 25
·期 2
·143-151
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IF 0
Du Jianzeng,Li Yonghong,Miao Zhenyu
Novel Ni/ZnO – HZSM-5 adsorbents were synthesized by incipient wetness impregnation. The Ni/ZnO – HZSM-5 adsorbent can achieve deep desulfurization and olefin aromatization at the same time. Thiophene sulfur was removed from 495 to less than 10 ppm via reactive adsorption desulfurization (RADS). Olefins were also converted into aromatics. HZSM-5 did not only support adsorbents but also cooperated with active Ni sites to catalyze olefins into aromatic hydrocarbons. Aromatization of 1-pentene, 2-pentene, 2-methyl-2-butene, and 1-hexene on adsorbents was investigated. The adsorbents were characterized by the Brunauer–Emmett–Teller, X-ray diffraction, temperature-programmed reduction, and temperature-programmed desorption of ammonia and thermogravimetric analysis. The experimental results showed that strong acids on the adsorbent disappeared after HZSM-5 loaded active metal sites, and almost no coke was generated on adsorbents in RADS.
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ENERGY & FUELS
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2018
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IF 3.024
Tingting Huang,Jingyao Chang,Shuisen He,Chenglong Wen,Yu Fan
This paper proposes a novel one-step hydrothermal polyoxometalate (POM) dispersion method for synthesizing NiMo/Al2O3 hydrodesulfurization (HDS) catalysts with high Ni/Mo atomic ratios. The proposed method disperses Mo12O30(μ2-OH)10H2[Ni(H2O)3]4 on the surface of Al2O3 under a hydrothermal environment, which promotes the formation of highly dispersed MoS2 slabs with increased stacking. The proximity between Ni and Mo in POM improves the decoration of MoS2 slabs by Ni, and the high Ni/Mo ratio of POM synthesized by the one-step method ensures that the corresponding catalyst possesses a high concentration of active NiMoS phases. The as-prepared POM-based NiMo/Al2O3 catalyst possesses much better activity in 4,6-dimethyldibenzothiophene HDS than its counterparts synthesized via the traditional incipient wetness impregnation method.
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JOURNAL OF CHEMICAL AND ENGINEERING DATA
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2018
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IF 2.196
Ying Zhang,Yutian Chen,Taotao Zhan,Maogang He
The speed of sound in n-heptane was measured by the Brillouin light scattering (BLS) method. The examined region is T = (513.40 to 650.90) K along seven isobaric lines at p = (2.5, 3.0, 4.0, 5.0, 6.0, 8.0, and 10.0) MPa, which was near the critical point of n-heptane. The relative expanded uncertainty (k = 2) of BLS experimental system is estimated to be <0.013 for the speed of sound measurement. The variation tendencies of the speed of sound with increasing temperature and pressure were illustrated. Moreover, the calculated results from the multiparameter equation of state (EOS) proposed by Span and Wagner were employed to assess the experimental data in this paper. The absolute average of the deviations (AAD) between the experimental data and the calculated results is 1.22% in the whole investigated p–T region.
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ENERGY CONVERSION AND MANAGEMENT
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2018
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IF 6.377
Dongren Cai,Yiwei Xie,Ling Li,Jieyong Ren,Xiaocheng Lin,Ting Qiu
With the combination of molecular simulation and relevant experiments, the efficient Brønsted-Lewis acidic ionic liquid (IL) was designed and synthesized for biodiesel production from soapberry oil. In molecular simulation, 4-methylthiazole (MT) is proved to be the best matrix for IL preparation via electrostatic potential analysis and proton affinity analysis, and it also is verified by experiments. In orthogonal experiment, the relationship in catalytic activity between Brønsted-Lewis acidic IL and corresponding materials (Brønsted acidic IL and metal chloride) was revealed. Meanwhile, [Ps-MTH][CF 3 SO 3 ] and FeCl 3 are verified as the best materials for preparation of Brønsted-Lewis acidic IL, and [Ps-MTH][CF 3 SO 3 ]-FeCl 3 ( x = 0.65) is determined as the most efficient catalyst in the end. The Lewis acidity, Brønsted acidity and interaction of [Ps-MTH][CF 3 SO 3 ] and FeCl 3 in [Ps-MTH][CF 3 SO 3 ]-FeCl 3 ( x = 0.65) were characterized by FT-IR. And the catalytic mechanism of transesterification catalyzed by prepared IL was clarified. In order to maximize the biodiesel yield, optimization of process variables was conducted using Box-Behnken response surface methodology. The 97.04% of high biodiesel yield is obtained under the optimum conditions: reaction temperature was 127 °C, molar ratio (methanol to soapberry oil) was 27.96:1, catalyst amount was 3.06 mmol and reaction time was 8 h. Furthermore, [Ps-MTH][CF 3 SO 3 ]-FeCl 3 ( x = 0.65) presents good catalytic activity in different transesterification for biodiesel production. And its catalytic activity decreases from 97.04% to 93.59% after being used for 5 times, which reflects good reusability. The main properties of soapberry biodiesel were also measured and compared to the ASTM D6751 standard.
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ACS Applied Materials & Interfaces
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2018
·
IF 8.097
Ebrahim Ataeivarjovi,Zhigang Tang,Jian Chen
In this present work, a novel approach has been proposed by which a solvent absorption and membrane desorption methods can significantly reduce the carbon dioxide (CO2) emission and energy consumption. In this method, the CO2 capture processing is based on the combination of membrane and physical solvent. Here, dimethyl carbonate and polydimethylsiloxane (PDMS)–SiO2 nanocomposite were used as the physical solvent and desorption membrane, respectively. However, the main focus of this research was on the CO2 desorption behavior of PDMS–SiO2 hybrid membrane. To do so, the influence of the operating conditions and membrane properties on the pervaporation process to capture CO2 have been investigated. The PDMS–SiO2 hybrid membrane containing 10 wt % SiO2 was the most effective membrane. Results revealed that increase in CO2 concentration from 1.5 to 3 wt % led to decrease in the selectivity from 94 to 47 and increase in flux from 1.7 to 5.38 (kg/m2·h). In addition, an increase in temperature increased the flux and reached the highest level (8.17 kg/m2·h) at 40 °C. However, the selectivity decreased to 36.13. It was found that the addition of SiO2 nanoparticles to the PDMS membrane not only enhanced the membrane performance but also decreased the energy consumption about 75% compared with gas stripping method and mass transfer about 49% compared with pure PDMS membrane. Finally, these results illustrated that such a novel technique used for pervaporation separation process is a green and promising alternative to separate CO2 from the physical solvent.
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Small
·
2019
·Vol. 15
·期 31
·1901888
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IF 10.856
Bin Shang,Min Chen,Limin Wu
Tunable underwater oil adhesion is a critical issue in interfacial science and industrial applications. Although much progress has been made to date, development of novel smart coating materials that can selectively change the wetting property at different areas is considerably scarce. Here, a simple strategy is proposed to fabricate photothermal responsive coatings, which can change the oil adhesion behavior from low-adhesive rolling state to high-adhesive pinning state for a variety of oily liquids in a remote, local, and reversible manner. Owing to this unique controllability, the adhesion and no-adhesion of oil droplets on the coated surfaces can be easily manipulated by remote and local near-infrared radiation.
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危险品化学品经营许可证（带存储）