Co-reporter:Yanqing Tang, Yangcheng Lu, and Guangsheng Luo
Industrial & Engineering Chemistry Research September 13, 2017 Volume 56(Issue 36) pp:10036-10036
Publication Date(Web):August 17, 2017
DOI:10.1021/acs.iecr.7b02039
Micro–nano-assembled manganese carbonate (MnCO3) was synthesized via aqueous precipitation assisted by ethanol. The effects of time and the flow rate of ethanol introduction on the morphology and size of products were carefully investigated. The results reveal that ethanol may participate in the precipitation of MnCO3 nanoparticles, the retarding of aggregate fusion, and the reassembly of aggregates at different stages. By a delayed but swift introduction of ethanol, we can regulate these effects to endow the micro–nano-assembled MnCO3 with high surface area, uniform morphology, and calcination-resistant skeleton simultaneously. The synthesis of monodispersed micro–nano-assembled MnCO3 at elevated concentrations of reactants is also possible by introducing ethanol earlier.
Co-reporter:Xiaojing Liu, Yangcheng Lu, and Guangsheng Luo
Industrial & Engineering Chemistry Research August 30, 2017 Volume 56(Issue 34) pp:9489-9489
Publication Date(Web):August 14, 2017
DOI:10.1021/acs.iecr.7b02352
Conducting emulsion polymerization in continuous flow mode for polymer nanoparticle synthesis has the potential to improve productivity and reliability but has to face the fact that the emulsion is difficult to remain stable without stirring. In this work, a mixed nonionic–anionic emulsifier TX-100/SDBS (4:1) was found to perform much better in stabilizing pre-emulsion than anionic emulsifier SDBS and then was exploited in the microflow system to achieve reliable operation, controllable conversion, and continuous synthesis of nanoparticles with uniform size (PDI < 0.09). The reaction temperature could be elevated to 95 °C, and the emulsifier concentration could be decreased to 8.515 mM. The average size of the nanoparticles was facilely adjusted from 52 to 92 nm by changing the emulsifier concentration.
Co-reporter:Tongbao Zhang;Guangsheng Luo;Dawei Xin
Industrial & Engineering Chemistry Research April 23, 2014 Volume 53(Issue 16) pp:6723-6729
Publication Date(Web):2017-2-22
DOI:10.1021/ie500503b
A microreactor competent to control the microprecipitation environment is exploited to investigate the direct precipitation process between iron and phosphorus sources. The dependency of the reaction species on the purity of the final products is revealed. The Fe3+ hydrolysis and the pH of the mixture are confirmed to have decisive influences on the generation of byproducts. The addition of phosphoric acid in the iron source is verified to be an effective method to simultaneously inhibit Fe3+ hydrolysis and adjust the pH of the mixture. By optimizing the amount of phosphoric acid addition, pure nanoiron phosphate with an average size of ca. 20 nm is successfully prepared by a continuous precipitation process. Assuming instantaneous mixing and fast precipitation reactions, Fe3+ and HPO42– are indicated as the main species during the pure iron phosphate precipitation. The criteria would lay a practical guidance for achieving a continuous synthesis of nanoiron phosphate with high purity.
Co-reporter:Shan Zhu;Rudolf Faust
RSC Advances (2011-Present) 2017 vol. 7(Issue 44) pp:27629-27636
Publication Date(Web):2017/05/22
DOI:10.1039/C7RA05246D
In this work, a micromixing module was utilized in the polymerization of isobutylene (IB) initiated by tert-butyl chloride (t-BuCl) and catalyzed by ethylaluminum dichloride (EADC)/bis(2-chloroethyl)ether (CEE) complex for the synthesis of highly reactive polyisobutylene (HRPIB). Better micromixing performance resulted in HRPIB with narrower molecular weight distribution, where the PDI could be decreased from 3.5 without micromixing module to 2.5 or less. The polymerization rate also increased while the molecular weight and content of exo-olefin end groups of HRPIBs could be adjusted conveniently by the ratio of CEE to EADC and monomer concentration. A dynamic mechanism was proposed to explain the effects of micromixing on the enhanced HRPIB synthesis.
Co-reporter:Tongbao Zhang, Xin-Bing Cheng, Qiang Zhang, Yangcheng Lu, Guangsheng Luo
Journal of Power Sources 2016 Volume 324() pp:52-60
Publication Date(Web):30 August 2016
DOI:10.1016/j.jpowsour.2016.05.071
•Construct uniformly dispersed a-FePO4 and CNT nanocomposite through interface interaction.•Achieve high energy density for lithium-ion battery based on a-FePO4.•Present the best rate capacity of a-FePO4 as cathode for lithium-ion battery.•Reveal excellent long-term stability of a-FePO4 as cathode for lithium-ion battery.Using amorphous FePO4 (a-FePO4) nanoparticles with a high purity, a narrow size distribution and good dispersion, we successfully developed a new strategy to generate a uniformly dispersed a-FePO4-CNT nano-composite using the interface interaction between surface-modified a-FePO4 and CNT dispersion under mild sonication. The uniformly dispersed a-FePO4-CNT nano-composite exhibited the best performance and long-term stability as a cathode material in a lithium-ion battery compared to previously reported results. The developed nano-composite could deliver a theoretical specific capacity at 0.1 C, 162 mAh g−1 at 1 C and 117 mAh g−1 at 5 C. No capacity fading was observed at 1 C after 500 cycles, and nearly 90% of the initial discharge capacity could be retained at 5 C after 2000 cycles. This study confirms the validity of the proposed strategy to construct a cathode structure, and also describes the potential of a-FePO4 for building high-power energy-storage and conversion systems.
Co-reporter:S. Zhu, Y. C. Lu, K. Wang and G. S. Luo
RSC Advances 2016 vol. 6(Issue 12) pp:9827-9834
Publication Date(Web):18 Jan 2016
DOI:10.1039/C5RA26553C
In this work, with AlCl3 addition in the range from 4 to 10 mmol L−1 and enough isopropyl ether (iPr2O) addition, we successfully synthesized highly reactive polyisobutylene (HRPIB) using a microflow system within 12 s or less. The temperature window was extended from −20 °C to 50 °C, and the molecular weight (Mn) was adjustable between 500 and 15000. The evolutions of HRPIBs and the effects of reaction conditions were carefully investigated, revealing multiple effects of an excess of iPr2O over AlCl3 including: (1) decreasing the intensive isomerization co-initiated by free AlCl3; (2) inhibiting the chain termination to present chain transfer dominated kinetics; (3) weakening the temperature sensitivity of Mn as a restriction on temperature elevation; (4) retarding the chain propagation to slow the reaction and increase the probability of isomerization. Key access to fast synthesis of high quality HRPIB is proposed to make a compromise of these effects by properly selecting iPr2O:AlCl3.
Co-reporter:Yangcheng Lu, Shan Zhu, Kai Wang, and Guangsheng Luo
Industrial & Engineering Chemistry Research 2016 Volume 55(Issue 5) pp:1215-1220
Publication Date(Web):January 13, 2016
DOI:10.1021/acs.iecr.5b04265
In this study, we use AlCl3/H2O as an initiation system to generate poly(isobutene-co-isoprene) within 1 s in a microflow device. This flash process is almost independent of the temperature over the range from −92 to −65 °C but is highly sensitive to the mixing intensity during the initial system injection. Assuming a one-to-one correspondence of the polymer chain and effective initiator, there is an optimal ratio of AlCl3 to H2O to achieve high-efficiency chain initiation. Considering the free HCl and H2O as chain termination agents in the flash process, a dimensionless calibration is obtained to quantitatively present how the monomers, effective initiators, and chain termination agents determine the product molecular weight. This work opens up the possibility of understanding cationic polymerization in-depth and achieving reliable, designable, and continuous production of commercial poly(isobutene-co-isoprene), such as butyl rubber, at elevated temperatures.
Co-reporter:Tongbao Zhang, Yangcheng Lu, and Guangsheng Luo
ACS Applied Materials & Interfaces 2014 Volume 6(Issue 16) pp:14433
Publication Date(Web):July 16, 2014
DOI:10.1021/am503708a
To develop a green, cost-efficient and robust peroxidase mimic, micro/nano hierarchical morphology (for ease of separation and reuse), relative chemically stable composition (for ease of storage) and stable crystal structure (for long-term stability) are highly desired. Herein, using phosphoric acid as a chelating ligand to control the release of iron ions, hierarchical iron(III) hydrogen phosphate hydrate crystals are successfully prepared by nanosheets formation and following self-assembling in a facile low-temperature hydrothermal process. They are first found to have peroxidase-like activity and showed higher affinity for H2O2 and lower affinity for 3,3′,5,5′-tetramethylbenzidine compared with horseradish peroxidase. The affinity feature is used for quantitative detection of H2O2 and shows a wide linear detection range from 57.4 to 525.8 μM (R2 = 0.994) with a low detection limit of 1 μM. Benefited from chemical stability of hierarchical iron(III) salt crystals, they own good reproducibility (relative standard deviation = 1.95% for 10 independent measurements), long-term stability (no activity loss after 10 cycles), and ease of recovery (by simple centrifugation). Because the method is easily accessible, iron hydrogen phosphate hierarchical crystals have great potential for practical use of H2O2 sensing and detection under harsh conditions.Keywords: H2O2 detection; hierarchical morphology; hydrothermal process; iron(III) hydrogen phosphate crystals; peroxidase mimic
Co-reporter:Y. Liu, Y. C. Lu and G. S. Luo
Soft Matter 2014 vol. 10(Issue 19) pp:3414-3420
Publication Date(Web):06 Feb 2014
DOI:10.1039/C3SM53003E
Towards developing a more universal and productive nanoprecipitation processes, we focus on the preparation of polysulfone (PSF) nanoparticles through instantaneous solvent displacement in a metal membrane contactor between dimethylformamide (DMF) and water. In the original nanoprecipitation process, cubic nuclei can form instantaneously, but slow growth and aggregation have intensive interactions. Moreover, the reservation of DMF may enhance the adhesive effect between polymeric particles, causing severe particle aggregation. To overcome this difficulty, a modified nanoprecipitation method appending a quenching step was proposed. The well-dispersed PSF nanoparticles are successfully obtained when ethyl acetate is introduced. In this way, DMF can be extracted from water solution, thus facilitating the precipitating of PSF. Furthermore, selecting water as the continuous fluid, the particle size can be adjusted simply by tuning the operating parameters, including the PSF concentration in the dispersed fluid and the ratio of two feeds. Compared with previous reports on the continuous nanoprecipitation process for polymeric nanoparticles preparation, this work shows advantages including expanding the adaptability to more functional polymers, providing better flexibility on process or product development independent of the use of surfactant, and presenting a high throughput and easy-to-scale-up equipment platform.
Co-reporter:Yangcheng Lu, Yang Liu, Chen Zhou, and Guangsheng Luo
Industrial & Engineering Chemistry Research 2014 Volume 53(Issue 27) pp:11015-11020
Publication Date(Web):2017-2-22
DOI:10.1021/ie5019832
Decreasing the size of Li2CO3 powder has benefits in its applications for drug delivery and materials manufacture. To this end, selecting a water–ethanol mixture as solvent, we investigate the precipitation reaction between LiOH and CO2 in a microfiltration membrane dispersion microreactor. The results show that both interphase mass transfer rate of CO2 and the solubility of Li2CO3 play important roles in a successful Li2CO3 nanoparticles preparation. The ratio of the solubilities of LiOH and Li2CO3 reaches nearly two orders higher than that in water at the mass fraction of ethanol (φ) being around 0.9, and 0.870 or higher of φ can guarantee obtaining nanoparticles with narrow size distribution (CV < 0.3). The particle size is sensitive to φ and the flux of liquid/slurry feed, and the increases of which can lead to the decreasing of particle size in the range from 150 to 30 nm. The usage of LiOH slurry with content up to 10 wt % can increase the particle size a little but does not affect the uniformity of nanoparticles in morphology. Such a Li2CO3 nanoparticles preparation process could be green with water as the only byproduct and discharge.
Co-reporter:Tong B. Zhang, Yang C. Lu, and Guang S. Luo
Crystal Growth & Design 2013 Volume 13(Issue 3) pp:1099-1109
Publication Date(Web):January 8, 2013
DOI:10.1021/cg301441t
In this work, pure iron phosphate products with various morphologies and crystal structures were obtained by coupling fast precipitation in a microreactor and the aging process. Morphology control from amorphous nanoparticle to monoclinic microsheet or microsphere can be simply realized by only changing the addition of H3PO4 in the reaction system. Microscopic observations on morphology evolvement revealed the formation of different morphology, or crystal structure could be illustrated by the synergetic effect of precursor produced in the mixing unit and postgrowth from solution in aging generally. Furthermore, Cr(III) adsorption determinations confirmed monoclinic-phase FePO4 had a better adsorption capacity than amorphous FePO4, and microsheet FePO4 has potential as a Cr(III) adsorbent with rationality in crystal structure, surface area, and macroscopic size.
Co-reporter:Tongbao Zhang, Yangcheng Lu and Guangsheng Luo
CrystEngComm 2013 vol. 15(Issue 44) pp:9104-9111
Publication Date(Web):10 Sep 2013
DOI:10.1039/C3CE41570H
In this work, the single-crystal dendritic iron hydroxyl phosphate is synthesized via a facile and well-controlled hydrothermal process without any additional surfactant or template. The morphology of the product at various scales is characterized by scanning electron microscopy and transmission electron microscopy. The phase and crystal structure is determined and carefully confirmed by using X-ray powder diffraction, high resolution transmission electron microscopy and selected area electron diffraction combined with thermal analysis comprehensively. A reasonable self-template route, as well as the precipitation–dissolution–recrystallization process is revealed according to the time dependence of morphology, crystal structure, zeta potential and precipitate amount. Finally, the single-crystal dendrite is tested as a Fenton catalyst for the degradation of phenol, a typical advanced oxidation process (AOP). Attributed to the perfect crystal structure and the hierarchical architecture, this novel catalyst presents numerous advantages including remarkable catalytic activity over a wide pH range (e.g., pH = 3–8), outstanding cycle performance (no observation of activity loss in five runs), and extremely low leaching iron concentration (below 0.5 mg L−1).
Co-reporter:Tongbao Zhang, Yangcheng Lu, Jianquan Liu, Kai Wang, and Guangsheng Luo
Industrial & Engineering Chemistry Research 2013 Volume 52(Issue 16) pp:5757-5764
Publication Date(Web):April 1, 2013
DOI:10.1021/ie400547z
The ammonium silicofluoride ammonification process is a potential atomic economical process for nanosized silica preparation. In this work, this process was continuously conducted in a micropores dispersion microreactor and specially investigated. The exploration on the evolution of the yield and the specific surface area of product with reaction proceeding under various feeding conditions indicated that both of two consequent stages of fast precipitation and precipitate aging may occur remarkably in the microchemical system. However, their overlap could be reduced by enhancing mixing and strictly controlling the residence time. Correspondingly, this process could stably preparing high-quality SiO2 nanoparticles (specific surface area >400 m2/g) at equilibrium yield. Furthermore, optimization on reaction temperature was discussed, and the adaptability of high concentration (NH4)2SiF6 as feed was tested as well. This research provided fundamentals and a guide for developing and designing an industrial production technology of nanosized silica based on the ammonium silicofluoride ammonification process.
Co-reporter:Tongbao Zhang, Yangcheng Lu, and Guangsheng Luo
Industrial & Engineering Chemistry Research 2013 Volume 52(Issue 21) pp:6962
Publication Date(Web):May 9, 2013
DOI:10.1021/ie400192y
In this work, the size adjustment of FePO4 nanoparticles in the range of 9–50 nm was conducted on a general platform of coupling fast precipitation in a microreactor and thermal treatment process. Specifically, we used the mixture of nitric acid and phosphoric acid as the continuous fluid to change the free Fe3+ concentration and control the supersaturation of FePO4 in fast precipitation. Inductively coupled plasma optical emission spectroscopy (ICP-OES) and X-ray diffraction (XRD) verified that as-prepared nanoparticles were high-purity amorphous FePO4·2H2O. Transmission electron microscopy (TEM) verified their good dispersity and narrow size-distribution (standard deviation, ∼5 nm). Brunauer–Emmet–Teller (BET) and Cr (III) adsorption verified their property accordant as ion adsorbents. The effect of mixed acids on species with respect to iron was also investigated by UV–vis spectra. The technique would be easily scaled up for size controllable and property accordant FePO4 nanoparticles preparation.
Co-reporter:Zhendong Liu;Man Zhang;Weiming Wan;Guangsheng Luo
Journal of Applied Polymer Science 2013 Volume 129( Issue 3) pp:1202-1211
Publication Date(Web):
DOI:10.1002/app.38662
Abstract
The expansion of polymer nanosphere applications requires facile and versatile preparation techniques. In this study, combining circled premix membrane emulsification and thermally initiated miniemulsion polymerization, we developed a new strategy for preparing uniform polystyrene nanospheres within a duration as short as 1 h. The size of the nanospheres, ranging from 40 to 120 nm, was dependent on the premix membrane emulsification cycle number, the transmembrane flow rate, and the membrane pore size; this was almost consistent with characterizations of droplet size evolution. The coefficient of variation, around 15%, indicated that the size distribution of the nanospheres was still narrow, even as the monomer-to-water ratio was as high as 0.2. This method may be competitive for further applications because of its high production efficiency and low system requirements. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Co-reporter:Liu Zhendong;Lu Yangcheng;Yang Bodong ;Luo Guangsheng
Journal of Applied Polymer Science 2013 Volume 127( Issue 1) pp:628-635
Publication Date(Web):
DOI:10.1002/app.37832
Abstract
Monodispersed droplets could be easily generated in coaxial microdevice, and a reaction based upon these discrete droplets is an attractive approach thanks to isolated reaction units, efficient mixing, and precise residence time control. In this work, free radical polymerization of butyl acrylate was conducted in monodispersed droplets of several hundred microns. Two different heating methodologies, microwave heating and conventional heating with oil bath were adopted to initiate polymerization, respectively. The polymerization under conventional heating could be regarded as an isothermal process, while the polymerization under microwave heating gradually underwent a temperature increase. So the poly (butyl acrylate) obtained by microwave heating has larger average molecular weight and higher polydispersity index. Meanwhile, the conversion of butyl acrylate was significantly improved by microwave heating compared with conventional heating, even though the reaction temperature under microwave heating might be lower than the temperature of the oil bath. This remarkable enhancement was a direct proof of the nonthermal effect of the microwave field for free radical polymerization. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Co-reporter:Rui Wang, Yangcheng Lu, Kai Wang, and Guangsheng Luo
Journal of Chemical & Engineering Data 2013 Volume 58(Issue 11) pp:3222-3225
Publication Date(Web):October 28, 2013
DOI:10.1021/je400681a
Liquid–liquid equilibrium data for the ternary system of water + 1,3-dichloro-2-propanol + epichlorohydrin were determined at the temperature of (283.15, 293.15, 303.15) K and atmosphere pressure. The reliability of experimental method was examined by the mass balance verification and the Othmer–Tobias equation. The experimental data were successfully correlated with both the NRTL model and UNIQUAC model, and the NRTL model presents more satisfactory result. These LLE data and model parameters obtained in this work are helpful for understanding, designing, and developing epichlorohydrin synthesis processes.
Co-reporter:Bodong Yang, Yangcheng Lu, Tingwei Ren, Guangsheng Luo
Reactive and Functional Polymers 2013 73(1) pp: 122-131
Publication Date(Web):January 2013
DOI:10.1016/j.reactfunctpolym.2012.08.012
Co-reporter:Bodong Yang, Yangcheng Lu, and Guangsheng Luo
Industrial & Engineering Chemistry Research 2012 Volume 51(Issue 26) pp:9016-9022
Publication Date(Web):June 12, 2012
DOI:10.1021/ie3004013
A thermal-initiated polymerization procedure is described for the controlled preparation of monodispersed polyacrylamide (PAM) hydrogel microspheres. A coaxial microfluidic device was designed to disperse uniform drops (∼500 μm) of acrylamide monomer aqueous solution into n-octane. Using a delay loop immersed into a heat bath, the polymerization is initiated and carried out in separate droplets. Combining the improvement of heat transfer in the microfluidic device and the sufficient addition of n-octane, the controllable preparation can still be achieved at 95 °C, much higher than 20–60 °C as reported prevalently. Herein, the PAM microspheres can be prepared within 2 min or less, with the CV of diameter less than 4%. Furthermore, based on this controllable reaction platform, PAM microspheres were prepared at various reaction temperatures (higher than 90 °C) and monomer solution compositions to investigate the fundamental rules of controlling on their skeleton structure and absorbent capacity in deionized water.
Co-reporter:Jisong Zhang, Jing Tan, Kai Wang, Yangcheng Lu, and Guangsheng Luo
Industrial & Engineering Chemistry Research 2012 Volume 51(Issue 45) pp:14685
Publication Date(Web):October 26, 2012
DOI:10.1021/ie301816k
A microchemical system, including two micromixers and a delay loop, is specially designed to carry out the chlorohydrination of allyl chloride with chlorine in water. Chlorine is dissolved in water in the first micromixer and then reacts with allyl chloride to produce dichloropropanol in the second micromixer. The reaction can be accomplished in the delay loop with a residence time less than 10 s and the selectivity higher than 98%. A multistage strategy which connects several microchemical units in series has been developed and demonstrated. The dichloropropanol concentration higher than 6 wt % with the selectivity higher than 96% can be successfully reached using this strategy. The results show that low temperature and high pressure could greatly improve the microreaction performance. In contrast to the conventional reaction process, the microreaction process has the advantages for higher yield, higher dichloropropanol concentration, less water waste, and lower energy consumption. Moreover, the new process could make the reaction process employing chlorine more controllable and safe.
Co-reporter:Zhendong Liu, Yangcheng Lu, Bodong Yang, and Guangsheng Luo
Industrial & Engineering Chemistry Research 2011 Volume 50(Issue 21) pp:11853-11862
Publication Date(Web):September 12, 2011
DOI:10.1021/ie201497b
In this work, a new controllable and continuous free radical polymerization process was developed and characterized in a coaxial capillary microreactor. In this process, the monomer solution was first dispersed into monodispersed droplets followed by thermal-initiated polymerization in the following capillary immersed in an oil bath. Poly(butyl acrylate) prepared in this microreactor possessed a much higher average molecular weight (Mn) and far lower polydispersity index (PDI) than that produced in a typical stirred vessel. The microreactor method possesses two unique advantages which allow for the optimization of the free radical polymerization process. First, the use of highly monodispersed droplets as polymerization units ensures that the polymerization process occurs uniformly in each individual droplet. Second, the small droplet size, on the order of several hundred micrometers, greatly enhances heat transfer efficiency with no heat accumulation within the droplets during polymerization. A simplified numerical simulation was used to show the superiority of the microreactor in effectively removing polymerization heat due to the miniaturization of the droplets to submillimeter scale. Simulation results also demonstrated that, in contrast to polymerization processes occurring in macroreactors, the polymerization conducted in the microreactor proceeded in a nearly isothermal condition. Experimental results in the microreactor showed that the molecular weight distribution was mainly determined by the size of the droplet, while the molecular weight of the polymer could be adjusted by changing the reaction temperature and 2,2-azobis(isobutyronitrile) concentration. This type of microreactor can potentially be applied to research involving the mechanisms of highly exothermic free radical polymerization processes and can also be used as an efficient tool for their controllable preparation.
Co-reporter:Yangcheng Lu;Yang Xia;Guangsheng Luo
Microfluidics and Nanofluidics 2011 Volume 10( Issue 5) pp:1079-1086
Publication Date(Web):2011 May
DOI:10.1007/s10404-010-0736-7
Aqueous two phase systems (ATPSs) have good biocompatibility and special selectivity. Their phase equilibrium and applications in biological analysis have received much attention. Herein, parallel laminar flow (PLF) in the microchannel can provide an effective platform to enhance mass transfer and preserve separate phases simultaneously. As fundamentals in feasible and convenient sampling of PLF for ATPS, the phase separation methods and rules in branched microchannel were studied in this work, selecting PEG 4000 + Na2SO4 + H2O as a model system. The exploration of flow pattern showed that a stable PFL was easily to form in the shallow microchannel of 200 μm (depth) × 600 μm (width), as long as the velocity of lower phase was higher than 0.51 mm/s. The phase interface of PLF could be easily controlled by the flow ratio of two phases. Single-phase separation could be reliably achieved in T-junction outlets when the flow rate of outlet ascertains to be smaller or larger than that of inlet on the same side. The trifurcate outlets with an extra middle channel could help realize a simultaneous two-phase separation. The flow rate of the extra channel is the key for the phase separation performance, the range of which available for simultaneous two-phase separation is determined by the resistance balance and the flow rates deviation offsetting as well. It is favor for increasing phase separation efficiency to make the products of flow rate, viscosity, and the length of corresponding outlet channel close with each other for the upper phase and the lower phase. The adjustable lengths of three channels can provide flexible choices to enhance simultaneous two-phase separation of diversified ATPSs at various operating flow ratios. A multiport microchip with T-junction inlets and trifurcate outlets designed for adjusting the lengths of branched channels on-chip is a convenient tool for PLF contact and in situ phase separation of ATPSs in varieties of application.
Co-reporter:Yangcheng Lu, Xiaochuan Yang and Guangsheng Luo
Journal of Chemical & Engineering Data 2010 Volume 55(Issue 1) pp:510-512
Publication Date(Web):July 14, 2009
DOI:10.1021/je900324s
Experimental liquid−liquid equilibrium data were measured for benzene + cyclohexane + 1-butyl-3-methylimidazolium hexafluorophosphate ([C4mim]PF6) at atmospheric pressure and (298.2, 308.2, and 318.2) K. The selectivity of [C4mim]PF6 for benzene is in the range of (20 to 60) when the mass fraction of benzene in the cyclohexane-rich phase is less than 0.08, which increases with a decrease in benzene content. The selectivity is also dependent on the temperature. The highest selectivity is obtained at 308.2 K in this work. Considering the high selectivity for benzene and the negligible solubility in benzene + cyclohexane mixtures, [C4mim]PF6 may be used as a potential extracting solvent for the separation of benzene and cyclohexane.
Co-reporter:Gao Mingyuan, Lu Yangcheng, Luo Guangsheng
Analytica Chimica Acta 2009 648(1) pp: 123-127
Publication Date(Web):
DOI:10.1016/j.aca.2009.06.040
Co-reporter:Yangcheng Lu;Yingxin Wu
Frontiers of Chemical Science and Engineering 2008 Volume 2( Issue 2) pp:204-208
Publication Date(Web):2008 June
DOI:10.1007/s11705-008-0027-y
To control the morphology of cellulose membranes used for separation, they were prepared by the NMMO method using water, methanol, ethanol and their binary solution as coagulation baths. Morphologies of the surface and cross section of dry membranes were observed. The pore structure parameters of wet membranes were determined. By comparison, the process and mechanism of pore formation in dry membranes were suggested, and the relativity of cellulose crystal size to average pore diameter in wet membranes and their influences were discussed. The results show that the morphology of dry membranes is clearly varied with coagulation baths, while the porosity of wet membranes is almost constant. Porous structures can appear in the compact region of dry membranes due to swelling from water. These pores have a virtual effect on the average pore diameter of wet membranes. By changing the composition of coagulation baths, the microstructure of cellulose membranes in a dry or wet environment can be adjusted separately.
Co-reporter:Lu Yangcheng, Lin Quan, Luo Guangsheng, Dai Youyuan
Analytica Chimica Acta 2006 Volume 566(Issue 2) pp:259-264
Publication Date(Web):4 May 2006
DOI:10.1016/j.aca.2006.02.072
This work describes a new sampling method termed directly suspended droplet microextraction (DSDME) was developed. In this technique a free microdroplet of solvent is delivered to the surface of an immiscible aqueous sample while being agitated by a stirring bar placed on the bottom of the sample cell. After some time, the microdroplet of solvent is withdrawn by a syringe and analyzed. Under the proper stirring conditions, the suspended droplet can remain in a top-center position of the aqueous sample. The droplet can become partly engulfed within the sample while maintaining a stable shape with mechanical equilibrium and the mass transfer could be effectively intensified. Using 1,8-dioxyanthraquinone as a model compound and 1-octanol as the solvent, the extraction performance was investigated using HPLC. Since DSDME is based on a self-stable single microdroplet system, there are no requirements for special equipment or other supporting material like hollow fibers. Other advantages include ease of operation, free from cross contamination, quick to reach extraction equilibrium, and the ability to be combined with various analysis instruments. In our experiments, good linearity (r2 = 0.9992) and precision (R.S.D. < 1%, n = 5) were achieved. DSDME is a promising pre-treatment method for the fast analysis of trace components in complicated matrices.
Co-reporter:Yangcheng Lu, Rui Wang, Jisong Zhang, Qianru Jin, Guangsheng Luo
Chinese Journal of Chemical Engineering (July 2015) Volume 23(Issue 7) pp:1123-1130
Publication Date(Web):1 July 2015
DOI:10.1016/j.cjche.2014.10.021
Synthesizing epichlorohydrin (ECH) from dichloropropanol (DCP) is a complicated reaction due to the partial decomposition of ECH under harsh conditions. A microchemical system can provide a feasible platform for improving this process by conducting a separation once full conversion has been achieved. In this work, referring to a common DCP feed used in industry, the reaction performance of mixed DCP isomers with NaOH in the microchemical system on various time scales was investigated. The operating window for achieving high conversion and selectivity was on a time scale of seconds, while the side reactions normally occurred on a time scale of minutes. Plenty of Cl− ions together with a high temperature were proved to be critical factors for ECH hydrolysis. A kinetic study of alkaline mediated ECH hydrolysis was performed and the requirements for an improved ECH synthesis were proposed by combining quantitative analysis using a simplified reaction model with experimental results on the time scale of minutes. Compared with the conventional distillation process, this new strategy for ECH synthesis exploited microchemical system and decoupled the reaction and separation with potentials of higher productivity and better reliability in scaling up.The enhancement of ECH synthesis process could be easily accessible and well predicted by decoupling reaction and separation in a microchemical system according to the difference of main reaction and side reactions in kinetics.Download full-size image
Co-reporter:Yangcheng Lu, Jing He, Longwen Wu, Guangsheng Luo
Chinese Journal of Chemical Engineering (February 2016) Volume 24(Issue 2) pp:323-329
Publication Date(Web):1 February 2016
DOI:10.1016/j.cjche.2015.10.002
In this work, an equilibrium-dispersion model was successfully established to describe the breakthrough performance of Ca(II) imprinted chitosan (Ca(II)-CS) microspheres packed column for metal adsorption, and the assumptions of Langmuir isotherms and axial dispersion controlled mass transfer process were confirmed. The axial dispersion coefficient in Ca(II)-CS microspheres packed column was found to be almost proportional to the linear velocity and fit for prediction through single breakthrough test. Sensitivity analysis for breakthrough curve indicated the axial dispersion coefficient as well as Langmuir coefficient was sensitive variable for deep removal requirement. The retrieval of the adsorption isotherms of Ca(II)-CS microspheres from breakthrough curve was fulfilled by modelling calibration. A strategy based on the correlation between adsorption isotherms and breakthrough performance was further proposed to simplify the column adsorption design using absorbents with small/uniform size and fast adsorption kinetics like Ca(II)-CS microspheres to cut down the gap between lab and industry.Equilibrium-dispersion model is appreciate for Ca(II)-CS microspheres to correlate adsorption isotherms with breakthrough performance, and paves a shortcut for column adsorption design.Download high-res image (174KB)Download full-size image
Co-reporter:Gao Mingyuan, Lu Yangcheng, Luo Guangsheng
Analytica Chimica Acta (19 August 2009) Volume 648(Issue 1) pp:123-127
Publication Date(Web):19 August 2009
DOI:10.1016/j.aca.2009.06.040
In this paper, a novel suspended droplet microextraction method was developed for the detection of trace of organic compounds in water samples. The process was executed in a rotating extraction vial without the use of a stir bar. A single drop of octan-1-ol placed on top of the water sample was used as the solvent. The droplet remained on top of the water sample as a thin layer with an expanding surface area during the extraction stage, while during the sampling stage, the droplet was collected and sampled by inserting a needle. The volume of the microdroplet used was 3 μL or less, to ensure high organic compound sensitivity. The microextraction experimental setup was simple, utilizing centrifugal forces and possesses the advantages of low cross-contaminant/interference and applicability to water samples apt to emulsification. Nitrobenzene was selected as a model organic compound, and samples were analyzed using gas chromatography (GC) or UV–vis spectrometry. Analysis of the microextraction method results showed a relative standard deviation (RSD) less than 3.82%.
