Co-reporter:Lei Peng, Wenkang Lei, Ping Yu and Yunbai Luo
RSC Advances 2016 vol. 6(Issue 13) pp:10365-10371
Publication Date(Web):20 Jan 2016
DOI:10.1039/C5RA17728F
The separation of water and oil is a promising work due to the increasing worldwide oil pollution and leakage of chemical solvents. Superhydrophobic porous materials were prepared for their separation. In this work, various porous substrates of copper meshes, filter papers and polyurethane (PU) sponges were chosen to obtain superhydrophobic surfaces. Superhydrophobic surfaces were fabricated by polyvinylidene fluoride (PVDF) and hydrophobic nano-silica particle coatings through a spraying approach. The superhydrophobicity, stability of coatings and oil/water separation effect of these as-coated materials were studied. The results demonstrated that all the surfaces showed high water contact angles (>150°), good reusability and excellent oil selectively. Moreover, the coated filter paper was scaled up for practical use of removing trace water from mineral insulating oil in our group. It is promising that this superhydrophobic coating could be used in more applications.
Co-reporter:Wenkang Lei;Zaikun Wu;Jie Ma;Ping Yu
Research on Chemical Intermediates 2016 Volume 42( Issue 9) pp:6893-6905
Publication Date(Web):2016 September
DOI:10.1007/s11164-016-2503-1
Two routes to 1,2-cyclohexanediol were studied. Specifically: (a) the hydrolysis of cyclohexene oxide and (b) the direct dihydroxylation of cyclohexene with aqueous hydrogen peroxide. Both reactions were carried out with zeolites as catalysts under solvent-free conditions, aiming to establish green routes for the synthesis of 1,2-cyclohexanediol. In the first route, H-Beta and H-ZSM-5 zeolites were used as catalysts, respectively. According to the results, H-ZSM-5 was a suitable catalyst for the hydrolysis of cyclohexene oxide. A 88.6 % yield of 1,2-cyclohexanediol could be obtained at a 96.2 % conversion of cyclohexene oxide under mild conditions, and the catalyst could be reused for three times. Compared with H-ZSM-5, H-Beta gave a much lower selectivity (63 %), although it was more active. In the second route, Ti-Beta zeolites with three different Ti loadings prepared via a simple two-step strategy were characterized and used. The results indicated that it was the framework Ti species which was responsible for the catalytic activity. The resultant Ti-Beta-3 % could give a 90.2 % cyclohexene conversion at a 66.2 % selectivity of 1,2-cyclohexanediol.
Co-reporter:Mingjie Hu;Le Gao;Wei Fu;Xinhai Liu;Fucai Huang;Chi Huang
Journal of Chemical Technology and Biotechnology 2015 Volume 90( Issue 12) pp:2195-2207
Publication Date(Web):
DOI:10.1002/jctb.4533
Abstract
BACKGROUND
Butanol produced by fermentation from waste biomass suffers from low final concentration. Separation of butanol from its dilute aqueous solution is of significant importance. Among various separation methods, pervaporation has been proved to be one of the most promising methods for the butanol–water system and developing pervaporation membranes with high performance is therefore of interest.
RESULTS
A high performance interpenetrating polymer network (IPN) polyurethane (PU) pervaporation membrane was obtained, giving membrane selectivity of 130.3 with butanol permeability of 2.5 × 104 Barrer at 60 °C. Both membrane selectivity and butanol permeability increased with feed temperature at temperatures up to 60 °C and then decreased.
CONCLUSION
Hydroxyl-terminated polybutadiene (HTPB) based PU was used in pervaporation recovery of butanol. Pervaporation performance was obviously improved by formation of IPN structure. The pervaporation performance was studied using the solution-diffusion model and the mechanism of performance improvement was also studied. © 2014 Society of Chemical Industry
Co-reporter:Yangbo Huang, Haiyang Jin, Hao Li, Ping Yu and Yunbai Luo
RSC Advances 2015 vol. 5(Issue 128) pp:106113-106121
Publication Date(Web):09 Dec 2015
DOI:10.1039/C5RA20499B
In this study, a facile method has been developed to prepare high performance thin film composite (TFC) forward osmosis (FO) membranes, which was conducted by coating the surface of a polysulfone (PSf) substrate with polydopamine (PDA) prior to the interfacial polymerization of trimesoyl chloride and m-phenylenediamine. The PDA coating layer was investigated by ATR-FTIR, XPS, FESEM and contact angle measurements. Results showed that the PDA layer played the following roles: (1) endowing the PSf substrate with catechol and ethylamino groups to enhance the hydrophilicity, which resulted in a significant increase in water flux; (2) facilitating the formation of a denser selective polydopamine layer during the interfacial polymerization process to enhance salt rejection. The TFC membrane based on PDA coated dual PSf surfaces showed a water flux of 43.4 LMH and a salt flux of 6.46 gMH in pressure retarded osmosis (PRO) mode using 2 M NaCl as draw solution.
Co-reporter:Hao Li, Lei Peng, Yunbai Luo and Ping Yu
RSC Advances 2015 vol. 5(Issue 119) pp:98566-98575
Publication Date(Web):10 Nov 2015
DOI:10.1039/C5RA20891B
Membrane fouling and chlorine degradation are two of the major challenges the reverse osmosis (RO) membrane industry is facing in recent years. In the present study, a commercial aromatic polyamide RO membrane (XLE-400, DOW Co., Ltd.) was modified via surface coating of polydopamine (PDA) followed by the grafting of polyethylenimine (PEI). The successful modification was confirmed by X-ray photoelectron spectroscopy (XPS). Membrane surface properties were characterized through scanning electron microscopy (SEM), atomic force microscopy (AFM), zeta potential and contact angle. The results showed that modification enhanced the surface hydrophilicity, moved the surface charge towards the positive side and made the surface slightly rougher without damaging the surface peak-and-valley substrate. The influence of modification on the permselectivity of the membrane was also examined. The modified membrane had a higher salt rejection and a slightly lesser water flux than the unmodified membrane. Furthermore, the chlorination, fouling and simulated biofouling experiments were done. The results showed that, due to the abundant presence of grafted amino groups coming from PEI, the modified membrane exhibited higher chlorine resistance, anti-fouling and antibacterial properties.
Co-reporter:Hao Li;Ping Yu;Haigang Li
Journal of Applied Polymer Science 2015 Volume 132( Issue 10) pp:
Publication Date(Web):
DOI:10.1002/app.41584
ABSTRACT
Membrane-based separation technology is one of the most active separation technologies being employed in water treatment. Polyamides (PA) are widely used membrane materials because they exhibit excellent performance, such as high flux with high salt rejection, and enhanced stability against wide range of pH and temperature. Unfortunately, PA membranes exhibit extremely poor resistance to chlorine leading to increased operation costs and decreased membrane lifetime. In this study, we find new ways for prolonging membrane lifetime and reducing the operating costs by investigating the chlorination and modification of PA membranes. Varying concentrations of hypochlorite were used to chlorinate a commercial reverse osmosis membrane (BW-30, DOW). The results showed that short-time exposure to high concentrations of hypochlorite could cause more serious problems to membranes than long-time exposure to low concentrations under the similar total exposure. The performance of the chlorinated membranes was recovered to some extent after treatment with NaOH solution (pH 10), indicating that the alkali treatment could initiate the reversible regeneration of chlorinated membranes. Furthermore, an industrial grade epoxy resin was used to modify the membranes to enhance the chlorine resistance via the reaction between the amide nitrogen and epoxy bond. The successful modifications were confirmed by attenuated total reflectance Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, and atomic force microscopy. Moreover, the chlorination tests showed that the modifications performed in these experiments enhanced the chlorine resistance of the membranes, especially for the membranes exposed to low concentration of chlorine. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41584.
Co-reporter:Lei Peng, Hao Li, Yi Zhang, Jiao Su, Ping Yu and Yunbai Luo
RSC Advances 2014 vol. 4(Issue 87) pp:46470-46475
Publication Date(Web):09 Sep 2014
DOI:10.1039/C4RA06337F
Oil spills are a serious threat to environment and marine ecosystems; hence, it is urgent to identify an economic and efficient countermeasure to deal with them. In this work, a kind of superhydrophobic 3D porous material is fabricated for oil spill cleanup. Oil is selectively absorbed in the material at first, and then sucked by a pump. The superhydrophobicity and factors influencing oil collection rates are studied. The results show that the water contact-angle is 155°, and the oil collection rate can reach 2.8 g s−1 under appropriate conditions. A plurality of these materials can be connected to a similar pump simultaneously, forming a network for oil cleanup. As the 3D material together with the pumping method can realize a continuous cleanup with high efficiency, it can be thought of as a promising candidate for oil spill cleanup applications.
Co-reporter:Lei Peng;Shuai Yuan;Ge Yan;Ping Yu
Journal of Applied Polymer Science 2014 Volume 131( Issue 20) pp:
Publication Date(Web):
DOI:10.1002/app.40886
ABSTRACT
As the ecological damage caused by marine oil spills has become one main threat to marine ecological security, materials that can reduce environmental pollution are in high demand. In this study, a simple low-cost method for fabricating a hydrophobic polyurethane sponge was investigated. Its hydrophobicity was evaluated through the measurement of the contact angles of water and oil. The mechanical properties, oil-absorption capacity, and selectivity were also tested. The results show that this sponge exhibited good mechanical properties, a high absorption capacity and selectivity, and a high reusability (>200 times) in oil–water separation. More importantly, the absorbed oil could be collected by simple squeezing. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40886.
Co-reporter:Yi Zhang, Zaikun Wu, Shaoli Chen, Ping Yu, and Yunbai Luo
Industrial & Engineering Chemistry Research 2013 Volume 52(Issue 18) pp:6069
Publication Date(Web):April 10, 2013
DOI:10.1021/ie302928v
Given the fact that the basicity of imidazolate was higher than that of acetate, imidazolate-based ionic liquids (ILs) were developed to be studied. By combining six different cations, including traditional cation, functionalized cation, and dication, together with imidazolate, a series of ILs were prepared and found to be effective for CO2 capture. The mechanism of the studied ILs was proposed as the formation of the carboxylation reactions on C2 position of the imidazolium rings. A strong interaction between the newly formed carboxylate portion of the zwitterion and the C2–H proton of another cation was also formed, leading to a 0.5 molar ratios of CO2 to IL. In addition, the CO2 absorption capacity of dicationic IL was 1.0 molar ratio, twice that of the monocationic analogue. Significantly, an improvement on absorption result was exhibited by the amino-functionalized IL, but similar performance was not observed in the hydroxyl-functionalized one. The effects of operating pressure and temperature on CO2 absorption were also discussed.
Co-reporter:Tao Wan, Ping Yu, Shenggang Wang and Yunbai Luo
Energy & Fuels 2009 Volume 23(Issue 2) pp:1089-1092
Publication Date(Web):February 4, 2009
DOI:10.1021/ef800904b
In this study, the production of biodiesel from soybean oil by transesterification was carried out over sodium aluminate as a heterogeneous catalyst. The solid base showed high catalytic activity for methanolysis reaching a 93.9% yield under optimal reaction conditions (reflux temperature, 1.5 wt% of catalyst, 12:1 molar ratio of methanol/oil, and 50 min). The catalyst treated at different temperatures was characterized by inductively coupled plasma-optical emission spectroscopy (ICP-OES), X-ray diffraction (XRD), thermogravimetry/differential thermogravimetry (TG/DTG), and Fourier transform infrared spectroscopy (FT-IR). The reaction contained homogeneous and heterogeneous contributions at the same time. Removing water and carbon dioxide was an effective way to elevate the catalyst stability in methanol.
Co-reporter:J.-C. Wei;P. Yu;B. Cai;Y.-B. Luo;H.-Z. Tan
Chemical Engineering & Technology 2009 Volume 32( Issue 1) pp:114-119
Publication Date(Web):
DOI:10.1002/ceat.200800479
Abstract
The absorption rates of NO into aqueous solutions of NaClO2 blended with Na2CO3 were investigated in a stirred reactor. The experimental results showed that the reaction rate could be expressed as . An equation for a second-order reaction rate constant between NO and NaClO2, kmn = 5.79 · 1015 exp(–5557.26/T), was obtained. The addition of Na2CO3 into the solution of NaClO2 decreased the reaction rate constant. The optimal absorption conditions involved a NO concentration of 540 ppm, NaClO2 concentration of 50 mol m–3, Na2CO3 concentration of 10 mol m–3, temperature of 333 K and O2 concentration of 4 %, which were determined by an orthogonal experiment. Under these optimal conditions, it was possible for the absorption rate to reach up to 1.9271 · 10–5 mol/(s m2).
Co-reporter:Tao Wan;Ping Yu;Shangkun Gong;Qiang Li
Korean Journal of Chemical Engineering 2008 Volume 25( Issue 5) pp:998-1003
Publication Date(Web):2008 September
DOI:10.1007/s11814-008-0161-8
Biodiesel was synthesized from rapeseed oil by transesterification over Magnesium oxide loaded with KF. The catalytic activity strongly depends on the loading amount of KF and calcined temperature. We found that the reaction reached a 79.37% yield when the loading amount was at 35 wt% and calcined at 500 °C. The simply dried 30% KF/MgO at 80 °C was found to give equally good results from the catalyst calcined at 500 °C, avoiding the usual activation at high temperature. The catalysts were characterized by the Hammett indicator method, BET, TG/DTG, XRD, NMR, EDS, and FT-IR. According to the instrumental analysis, the activity in the transesterification probably belonged to coordinately unsaturated F− and liberation of hydroxide during preparation. The effects of methanol/oil ratio and catalyst amounts on the conversion were also studied in this paper.
Co-reporter:Lei Zhang;Ping Yu
Journal of Applied Polymer Science 2007 Volume 103(Issue 6) pp:4005-4011
Publication Date(Web):27 DEC 2006
DOI:10.1002/app.25604
Flat-sheet composite membranes were developed by the traditional phase inversion technique using poly;(vinyl alcohol) (PVA). PVA composite pervaporation (PV) membranes were prepared with crosslinked PVA selective layer and porous polyacrylonitrile (PAN) and polyether sulfone (PES) substrate layer material as supports for separating heat sensitivity substance ε-caprolactam (CPL) from CPL/water mixtures. Glutaraldehyde was used as crosslinking agent. The effect of the composition of glutaraldehyde on membrane stability and structure were investigated. The operating parameters, such as feed concentration and operating temperature, remarkably affected PV performance of the composite membranes. The composite membranes with PVA casted on PAN (PVA/PAN) showed superior PV performance than that casted on PES (PVA/PES). This study has also shown that the type of porous support plays an important role in the PV performance. As a result, this work has presented the information needed of the behavior of PV membranes for dehydration applications of industrial caprolactam. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 4005–4011, 2007
Co-reporter:Liao Dongmei;Luo Yunbai;Yu Ping;Chen Zhigang
Applied Organometallic Chemistry 2006 Volume 20(Issue 4) pp:
Publication Date(Web):27 FEB 2006
DOI:10.1002/aoc.1049
The acid dissociation constants of 2,4,6-trimercaptotriazine (H3TMT) were determined by acid-base titration and now can be employed in the preparation of complexes having specific Cu–TMT ratios. IR, EA and TGA characterized the compounds. We analyzed the relevant IR spectra and attribute 2910–2925, 3030–3250 and 3430 cm−1 to triazine ring overtone, NH stretching vibrations and water in the TMT complexes, respectively. The solubility of Cu–TMT complexes was determined with ICP-AES. The results indicate that Cu3 (TMT)2 · 2H2O (3) is much more insoluble and more stable than Cu (H2TMT)2 (1), Cu (HTMT)·0.5H2O (2) and CuS. The extremely small value of KSP for compound 3 (2.11 × 10−46) indicates that Na3TMT is a very advantageous chelating agent in precipitating complex copper (e.g. copper-ammine species) from industrial wastewaters. The influences of ammonia concentration, pH and settling time on the effectiveness of copper precipitation were investigated. Also, a ‘real world’ printed circuit board factory effluent initially containing 350.9 ppm of Cu was treated and it was found that more than 99.9% of the copper was removed from the solution as an insoluble compound 3. Copyright © 2006 John Wiley & Sons, Ltd.
