Lin Zhang

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Name: 张林; Lin Zhang

Organization: Zhejiang University

Department: College of Materials Science and Chemical Engineering

Title: Professor

TOPICS

Material Chemistry

Carbon Nanotubes

Chemicals
References

Chlorine-Resistant Polyamide Reverse Osmosis Membrane with Monitorable and Regenerative Sacrificial Layers

Co-reporter:Hai Huang, Saisai Lin, Lin Zhang, and Li’an Hou

ACS Applied Materials & Interfaces March 22, 2017 Volume 9(Issue 11) pp:10214-10214

Publication Date(Web):February 27, 2017

DOI:10.1021/acsami.6b16462

Improving chlorine stability is a high priority for aromatic polyamide (PA) reverse osmosis (RO) membranes especially in long-term desalination. In this Research Article, PA RO membranes of sustainable chlorine resistance was synthesized. Glycylglycine (Gly) was grafted onto the membrane surface as a regenerative chlorine sacrificial layer, and the zeta-potential was used to monitor the membrane performance and to conduct timely regeneration operations for chlorinated Gly. The Gly-grafted PA membrane exhibited ameliorative chlorine resistance in which the N–H moiety of glycylglycine served as sacrificial pendants against chlorine attacks. Cyclic chlorination experiments, combined with FT-IR and XPS analysis, were carried out to characterize the membrane. Results indicated that the resulting N-halamines could be fast regenerated by a simple alkaline reduction step (pH 10). A synchronous relationship between the zeta-potential and the chlorination extent of the sacrificial layer was observed. This indicated that the zeta-potential can be used as an on-site sensor to conduct a timely regeneration operation. The intrinsic mechanism of the surface sacrificial process was also studied.Keywords: chlorination; grafting membrane; regenerative membrane; reverse osmosis; zeta-potential;

Preparation and characterization of cyclodextrin functionalized polydimethylsiloxane films via interfacial self-assembly

Co-reporter:Tiefan Huang, Yubiao Niu, Fang Zhang, Lin Zhang, Shengfu Chen, Qiming Jimmy Yu

Applied Materials Today 2017 Volume 9(Volume 9) pp:

Publication Date(Web):1 December 2017

DOI:10.1016/j.apmt.2017.07.003

•A facile and practical strategy for preparing polydimethylsiloxane films with a cyclodextrin layer on surface was introduced.•The interface of water and oil phase was used as template for self-assembly of cyclodextrins.•The films can effectively remove dye molecules, such as congo red and methylene blue, from water.•The films can be used as drug delivery system for small-molecule drugs release.Functionalized surfaces have many applications in areas such as sensor technology, selective adsorbents and controlled drug release. In this paper, polydimethylsiloxane (PDMS) films functionalized with a layer of cyclodextrin (CD) were prepared by using a facile and practical interfacial molecular self-assembly strategy. The surface and film structures were characterized and confirmed with FTIR-ATR and XPS spectroscopy. The prepared films were also tested for adsorption capacities for molecules of congo red and methylene blue and inclusion capabilities for antibacterial drug ciprofloxacin hydrochloride. For the CD layer preparation, amphiphilic cyclodextrin (am-β-CD) was synthesized by region-selective modification of the primary hydroxyl groups of β-cyclodextrin with long aliphatic chains, and then self-assembled on the interface between water and a PDMS organic casting solution. A layer of am-β-CD molecules was assembled onto the surface of the PDMS substrate via the mechanisms of molecular chain entanglements and hydrophobic interactions, which was confirmed by various characterization techniques. Fluorescent molecular staining experiments indicated that the self-assembled cyclodextrins layer on the PDMS substrate surface mostly retained the ability to include guest molecules. Adsorption tests showed that the functionalized films had a much higher adsorption capacity for the dye molecules than that of bare PDMS films. Inclusion experiments also showed that ciprofloxacin hydrochloride loaded functionlized PDMS films exhibited excellent antibacterial performance, indicating that the films could be used as a reservoir to store small drug molecules. All these results demonstrated that the novel films prepared could have potential applications in various areas, such as drug-loaded system and water purification.Download high-res image (93KB)Download full-size image

Aromatic Polyamide Reverse-Osmosis Membrane: An Atomistic Molecular Dynamics Simulation

Co-reporter:Tao Wei, Lin Zhang, Haiyang Zhao, Heng Ma, Md Symon Jahan Sajib, Hua Jiang, and Sohail Murad

The Journal of Physical Chemistry B 2016 Volume 120(Issue 39) pp:10311-10318

Publication Date(Web):September 7, 2016

DOI:10.1021/acs.jpcb.6b06560

Polyamide (PA) membrane-based reverse-osmosis (RO) serves as one of the most important techniques for water desalination and purification. Fundamental understanding of PA RO membranes at the atomistic level is critical to enhance their separation capabilities, leading to significant societal and commercial benefits. In this paper, a fully atomistic molecular dynamics simulation was performed to investigate PA membrane. Our simulated cross-linked membrane exhibits structural properties similar to those reported in experiments. Our results also reveal the presence of small local two-layer slip structures in PA membrane with 70% cross-linking, primarily due to short-range anisotropic interactions among aromatic benzene rings. Inside the inhomogeneous polymeric structure of the membrane, water molecules show heterogeneous diffusivities and converge adjacent to polar groups. Increased diffusion of water molecules is observed through the less cross-linked pathways. The existence of the fast pathways for water permeation has no effect on membrane’s salt rejections.

A cross-linking graphene oxide–polyethyleneimine hybrid film containing ciprofloxacin: one-step preparation, controlled drug release and antibacterial performance

Co-reporter:Tiefan Huang, Lin Zhang, Huanlin Chen and Congjie Gao

Journal of Materials Chemistry A 2015 vol. 3(Issue 8) pp:1605-1611

Publication Date(Web):30 Dec 2014

DOI:10.1039/C4TB01896F

A novel drug delivery system based on a graphene oxide film cross-linked by polyethyleneimine was prepared via a one-step preparation technique. Due to cross-linking, the stability of the film was significantly improved compared with the bare graphene oxide film and an extra drug-loading site was endowed to the film by PEI. The release behavior of ciprofloxacin, as a model drug, was investigated under various pH values in vitro, and the results exhibited slow drug release without an initial burst effect. Release kinetic models were employed to represent the drug release processes, and the release behavior of ciprofloxacin of the resulting cross-linking film was consistent with near zero-order kinetics. In comparison to a graphene oxide–polyethyleneimine hybrid film, the ciprofloxacin loaded hybrid film exhibited a significant antibacterial effect due to the ciprofloxacin release and diffusion from the film. This study provides insight into the design of suitable cross-linking GO hybrid films for biomedical field and many other applications.

Sol–gel fabrication of a non-laminated graphene oxide membrane for oil/water separation

Co-reporter:Tiefan Huang, Lin Zhang, Huanlin Chen and Congjie Gao

Journal of Materials Chemistry A 2015 vol. 3(Issue 38) pp:19517-19524

Publication Date(Web):14 Aug 2015

DOI:10.1039/C5TA04471E

A non-laminated graphene oxide membrane crosslinked by polyethyleneimine was prepared via a one-step sol–gel process. In the as-prepared membrane, the GO nanosheets remain disordered as in the sol state to form a randomly arranged GO self-assembled structure, which results in a much higher flux compared with the general laminated GO membrane prepared via vacuum filtration or spin coating because of the lower flow resistance. Furthermore, this random self-assembly of GO nanosheets gives rise to a hierarchical micro/nanoscale rough structure on the membrane surface. Along with the crosslinking reaction, PEI was grafted onto the GO nanosheets to make them hydrophilic. Combining the hydrophilic surface chemistry with the micro/nanoscale hierarchical surface structure, the non-laminated GO membrane exhibited the desired superhydrophilic and underwater superoleophobic properties. We have tested the membrane to separate a series of surfactant-free and surfactant-stabilized oil-in-water emulsions. A high separation efficiency (>99%) and flux were achieved using only gravity without any extra power, much larger than commercial filtration membranes with similar permeation properties. Moreover, the membrane shows an outstanding antifouling performance for oil droplets and can be recycled easily for long-term use.

Formation of cyclodextrin monolayer through a host–guest interaction with tailor-made phenyltriethoxysilane self-assembled monolayer

Co-reporter:Yubiao Niu, Tiefan Huang, Zhijun Zhou, Guohua Xu, Lin Zhang, Tao Wei

Colloids and Surfaces A: Physicochemical and Engineering Aspects 2015 470() pp: 224-229

Publication Date(Web):

DOI:10.1016/j.colsurfa.2015.01.088

Desalting and recovering naphthalenesulfonic acid from wastewater with concentrated bivalent salt by nanofiltration process

Co-reporter:Jiaxu Qin, Xingguo Dai, Yong Zhou, Lin Zhang, Huanlin Chen, Congjie Gao

Journal of Membrane Science 2014 468() pp: 242-249

Publication Date(Web):

DOI:10.1016/j.memsci.2014.05.055

Improving the performance of polyamide reverse osmosis membrane by incorporation of modified multi-walled carbon nanotubes

Co-reporter:Haiyang Zhao, Shi Qiu, Liguang Wu, Lin Zhang, Huanlin Chen, Congjie Gao

Journal of Membrane Science 2014 450() pp: 249-256

Publication Date(Web):

DOI:10.1016/j.memsci.2013.09.014

Acid and multivalent ion resistance of thin film nanocomposite RO membranes loaded with silicalite-1 nanozeolites

Co-reporter:Hai Huang, Xinying Qu, Xiaosheng Ji, Xin Gao, Lin Zhang, Huanlin Chen and Lian Hou

Journal of Materials Chemistry A 2013 vol. 1(Issue 37) pp:11343-11349

Publication Date(Web):19 Jul 2013

DOI:10.1039/C3TA12199B

The incorporation of NaA nanozeolites into thin film composite (TFC) reverse osmosis (RO) membranes has been found to elevate water permeability, but the unfavorable acid and multivalent ion sensitivity of NaA limits the application of the thin film nanocomposite (TFN) membranes for seawater desalination. To overcome these drawbacks, the chemically stable silicalite-1 nanozeolite was incorporated into the skin layer of the RO composite membrane via interfacial polymerization. In this paper, the resulting membrane was characterized with outstanding chemical stability (acid and multivalent cation tolerance) compared with the NaA mixed membrane. Additionally, silicalite-1 showed better capacity to enhance membrane permeability than NaA, which can be explained by larger channel pores and a higher water diffusion rate in silicalite-1. This investigation indicates that the silicalite-1 mixed membrane has great potential in large-scale seawater desalination because of its excellent permeability and chemical stability.

4-Dimethylaminopyridine Promoted Interfacial Polymerization between Hyperbranched Polyesteramide and Trimesoyl Chloride for Preparing Ultralow-Pressure Reverse Osmosis Composite Membrane

Co-reporter:Jiaxu Qin, Saisai Lin, Shuqin Song, Lin Zhang, and Huanlin Chen

ACS Applied Materials & Interfaces 2013 Volume 5(Issue 14) pp:6649

Publication Date(Web):June 24, 2013

DOI:10.1021/am401345y

We have presented a concept of ultralow-pressure reverse osmosis membrane based on hyperbranched polyesteramide through interfacial reaction promoted by pyridine derivate. In this strategy, a key catalyst of 4-dimethylaminopyridine, which can both eliminate the steric hindrance of acyl transfer reaction and facilitate the phase transfer in interfacial polymerization, is adopted to drive the formation of a thin film composite membrane from the hyperbranched polyesteramide and trimesoyl chloride. The results of the characterization demonstrate that a dense, rough, and hydrophilic active layer with a thickness of about 100 nm is formed when the 4-dimethylaminopyridine catalyst is used. The salt rejections for Na2SO4, NaCl, and MgSO4 of the as-prepared composite membrane are higher than 92%, especially for Na2SO4 with 98% rejection. The water fluxes reach about 30–40 L·m–2·h–1 even at an operation pressure of 0.6 MPa. The membrane exhibits good chlorine-resistance ability but poor resistance abilities to acidic and alkaline solutions in the physical–chemical stability experiment. It is also found that the resultant membrane possesses excellent separation performance for PEG-200, showing a promising way to separate small organic molecules from water.Keywords: hyperbranched polyesteramide; multifunctional catalyst; reverse osmosis membrane; ultralow-pressure;

Improving the antifouling property of polysulfone ultrafiltration membrane by incorporation of isocyanate-treated graphene oxide

Co-reporter:Haiyang Zhao, Liguang Wu, Zhijun Zhou, Lin Zhang and Huanlin Chen

Physical Chemistry Chemical Physics 2013 vol. 15(Issue 23) pp:9084-9092

Publication Date(Web):08 Apr 2013

DOI:10.1039/C3CP50955A

In this paper, isocyanate-treated graphene oxide (iGO), which can be well dispersed in organic solvent, was prepared in a simple manner and showed excellent compatibility with polysulfone (PSF). iGO–PSF ultrafiltration membranes were prepared by the classical phase inversion method. The separation performance and the antifouling property of the prepared membranes were investigated in detail. The antifouling property of the prepared membranes was found to be greatly enhanced by the addition of iGO, and we attributed the enhanced antifouling property to the improved hydrophilicity, the more negative zeta potential and the improved smoothness of the membrane surface.

A novel polysulfone-based affinity membrane with high hemocompatibility: preparation and endotoxin elimination performance

Co-reporter:Tiefan Huang, Mo Zhang, Lihua Cheng, Lin Zhang, Man Huang, Qiuping Xu and Huanlin Chen

RSC Advances 2013 vol. 3(Issue 48) pp:25982-25988

Publication Date(Web):23 Oct 2013

DOI:10.1039/C3RA43594F

A polysulfone (PSF)-based hollow fiber affinity membrane for in vitro endotoxin elimination was explored and prepared successfully. This depended on the well-known hemocompatibility of PSF membrane. The PSF hollow fiber membranes were firstly activated by a chloromethylation reaction, and treated with ethylenediamine and glutaraldehyde successively. L-Serine (Ser) was finally immobilized on the surface of the membranes as the functional ligand. The modified membrane was confirmed by X-ray photoelectron spectroscopy, attenuated total reflectance Fourier transform infrared spectroscopy, and contact angle analysis. L-Ser density up to 8.4 μmol cm−2 on PSF membranes could be achieved. The adsorption performance was preliminarily studied by comparing the PSF membrane and PSF–Ser membrane in deionized water and sodium phosphate buffer, showing that the PSF–Ser membrane had improved endotoxin adsorption capacity with decreased Bovine Serum Albumin (BSA) adsorption. The PSF–Ser membrane was further investigated in human plasma, and showed excellent removal efficiency and specificity for endotoxin. These results demonstrate the promising application potential of this novel affinity membrane in sepsis therapy.

Role of NaA zeolites in the interfacial polymerization process towards a polyamide nanocomposite reverse osmosis membrane

Co-reporter:Hai Huang, Xinying Qu, Hang Dong, Lin Zhang and Huanlin Chen

RSC Advances 2013 vol. 3(Issue 22) pp:8203-8207

Publication Date(Web):28 Mar 2013

DOI:10.1039/C3RA40960K

This paper explores the behaviour and role of NaA nanozeolites during an interfacial polymerization process towards a polyamide thin film nanocomposite (TFN) reverse osmosis membrane by incorporating nanozeolites into two different reactive phases. In the two cases, the different interactions occurring between the zeolites and polyamide were investigated by FT-IR spectra, XPS analysis, and examining the membrane morphology and the desalination performance. The polyamide TFN membrane with an increased degree of cross-linking was obtained with nanozeolites in the organic phase, as the NaA zeolite reacted with the acyl chloride monomer in the organic phase. Additionally, the membrane with nanozeolites added to the organic phase had a superior reverse osmosis performance, since the porous zeolite appeared in the top layer as a water channel.

Silane-modified NaA zeolite/PAAS hybrid pervaporation membranes for the dehydration of ethanol

Co-reporter:Ping Wei;Xinying Qu;Hang Dong;Huanlin Chen;Congjie Gao

Journal of Applied Polymer Science 2013 Volume 128( Issue 5) pp:3390-3397

Publication Date(Web):

DOI:10.1002/app.38555

Abstract

To improve the pervaporation selectivity of poly(acrylic acid) sodium (PAAS) membranes incorporated with NaA zeolite, the interface compatibility between zeolite nanocrystals and the polymer matrix was improved by modifying NaA zeolite using 3-aminopropyltriethoxysilane (APTES). Both X-ray photoelectron spectra and FTIR confirmed the chemical modification, while the results of zeolite particle size analysis and scanning electron microscopy revealed the improved dispersion of the modified zeolite. Transmission electron microscopy images of these hybrid membranes indicated that the interface between the polymer and modified zeolite phases had improved. The effects of loaded NaA zeolite on the pervaporation performance of hybrid membranes were investigated. The selectivity of hybrid membranes made from APTES-modified zeolite was higher than that using the original zeolite under the same conditions, because fewer voids resulted from the incompatibility between the zeolite and PAAS and the structure was more homogenous. Based on the Arrhenius plots, the activation energies of water and the ethanol ratio were lower for modified zeolite hybrid membranes, because water molecules experienced less restrictive passage through the membranes compared with the original zeolite-based hybrid membrane. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Ultrasonic treatment of polyacrylic acid sodium/NaA zeolite hybrid membranes for the pervaporation dehydration of ethanol

Co-reporter:Ping Wei;Xin Ying Qu;Hang Dong;Huanlin Chen;Congjie Gao

Journal of Applied Polymer Science 2013 Volume 130( Issue 6) pp:3979-3984

Publication Date(Web):

DOI:10.1002/app.39685

ABSTRACT

Ultrasonics was used to improve the dispersion of NaA zeolite in polyacrylic acid sodium (PAAS) membranes. The effect of ultrasonication time on the dispersion of NaA zeolite in the membranes, the membrane structure, and performance were investigated. The casting solution and resulting membranes were characterized by viscosity measurement, polarizing optical microscopy (POM), scanning electron microscopy, and X-ray diffraction (XRD). With increasing ultrasonication time, the viscosity of the casting solution decreased as the chain entanglements decreased. The POM and XRD results showed that crystallization occurred in the PAAS membrane after ultrasonic processing. A more homogeneous morphology was obtained due to improvement in the dispersion of zeolite under ultrasonic treatment for 0.5–1.0 h. As a result, the separation performance was enhanced. The water/ethanol separation factor increased from 176.2 to 577.8. However, the relative separation factor decreased when the ultrasonic time exceeded 2.5 h, due to the appearance of a lamellar structure. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3979–3984, 2013

Capturing carbon dioxide from air using a fixed carrier facilitated transport membrane

Co-reporter:Muhammad Syukri Abd Rahaman, Lin Zhang, Li-Hua Cheng, Xin-Hua Xu and Huan-Lin Chen

RSC Advances 2012 vol. 2(Issue 24) pp:9165-9172

Publication Date(Web):28 Aug 2012

DOI:10.1039/C2RA20783D

This paper reports the facilitated separation process of carbon dioxide (CO2) from air using polyethylenimine (PEI)–poly(vinyl alcohol) (PVA)/polyethersulphone (PES) hollow fibre composite membranes. The membranes were prepared by coating a thin layer of PEI–PVA on PES hollow fibre membranes. The prepared membranes were assembled and tested for CO2 permeance and CO2/N2 selectivity using compressed air as the feed. The effects of the PEI concentration and drying temperature for the preparation of composite membranes were investigated, the operation conditions were optimised, and the capability of capturing CO2 from air was evaluated using these membranes. The drying temperature for maximising the CO2 reaction was found to be 100 °C. It was found that the separation performance increased when the PEI concentration increased. The highest permeance for a membrane containing 6% PEI was 1.4 × 10−7 mol m−2 s−1 Pa−1 with a CO2/N2 selectivity of up to 300 at a lower pressure (1 bar). At a higher feed pressure (3 bar), the permeance increased by 300% from 2.6 × 10−8 mol m−2 s−1 Pa−1 to 7.7 × 10−8 mol m−2 s−1 Pa−1 when the feed flow rate was increased. By using 6% PEI in the membrane active layer, a CO2 concentration of up to 0.8% was collected on the permeate side at the higher feed pressure (3 bar). These results clearly show that CO2 can be concentrated from air by a facilitated transport mechanism.

Pervaporation Separation of Xylene Isomers by Hybrid Membranes of PAAS Filled with Silane-Modified Zeolite

Co-reporter:Xin Y. Qu, Hang Dong, Zhi J. Zhou, Lin Zhang and Huan L. Chen

Industrial & Engineering Chemistry Research 2010 Volume 49(Issue 16) pp:7504-7514

Publication Date(Web):July 2, 2010

DOI:10.1021/ie100256u

Silicalite-1 zeolite was modified with 3-aminopropyltriethoxysilane (APTES) and then loaded into poly(acrylic acid) sodium (PAAS) to prepare PAAS/silicalite-1 hybrid pervaporation membranes for the separation of xylene isomer mixtures. Characterization by Fourier transform infrared (FT-IR) and nuclear magnetic resonance (NMR) spectroscopies confirmed that chemical modification on the zeolite surface had taken place. Based on sorption equilibrium experiments, the diffusion coefficients of permeates in the membrane were obtained, and the order of the diffusion coefficients of xylene isomers was found to be Do < Dm < Dp. An investigation of the effects of the original versus modified zeolite loading on the pervaporation performance was performed. With the original zeolite, the permeation flux of the binary xylene mixtures showed little change, whereas the selectivity of the hybrid membrane exhibited some enhancement. After modification of the zeolite surface, the selectivity of the hybrid membrane was clearly improved, the permeation flux of the membrane decreased slightly, and the maximum separation factors of the p-/o-xylyne (αp/o) and p-/m-xylene (αp/m) mixtures were determined to be 2.62 and 2.68, respectively. The experimental results revealed that the modification promoted the compatibility of the PAAS and silicalite-1 zeolite interface.

Preparation and Pervaporation Property of Chitosan Membrane with Functionalized Multiwalled Carbon Nanotubes

Co-reporter:Shi Qiu, Liguang Wu, Guozhong Shi, Lin Zhang, Huanlin Chen, and Congjie Gao

Industrial & Engineering Chemistry Research 2010 Volume 49(Issue 22) pp:11667-11675

Publication Date(Web):October 12, 2010

DOI:10.1021/ie101223k

This study was designed to prepare functionalized multiwalled carbon nanotubes (MWNTs-COOH) incorporated chitosan membrane for separation of ethanol/water mixtures by pervaporation. The pristine MWNTs were treated by mixed acid and then functionalized by diisobutyryl peroxide. The structure and property of the functionalized MWNTs were characterized by Fourier transform infrared and Raman spectroscopies and transmission electron microscopy. A series of functionalized MWNTs incorporated chitosan membranes were prepared by solution blending method. The swelling degree of the resulting membranes in ethanol/water mixtures was 6 times that of the pristine chitosan membrane. The permeation flux of the membranes increased significantly with increasing functionalized MWNTs content in blend membrane matrix in pervaporation. On the basis of the experiments of sorption equilibrium, the solubility and the diffusion coefficient of membranes in water, ethanol, and 90% ethanol/water mixtures were obtained. Compared with the calculated diffusion coefficient (D90), the measured diffusion coefficient (D90T) in 90% ethanol/water mixtures was higher, taking M(2) for an example, D90 was 0.193 × 10−6 m2/s, and D90T was 0.41 × 10−6 m2/s, which indicated the functionalized MWNTs were more prone to increased water permeation when ethanol and water penetrated into the membrane simultaneously. In addition, effects of MWNTs content in the membrane matrix and operating temperature on pervaporation performances were investigated. After introducing functionalized MWNTs, the Arrhenius activation parameters for the total permeation decreased from 28.15 to 12.91 kJ/mol, which indicated that the carbon nanotubes filled membranes were easier to penetrate and exhibited higher flux performance than a pristine membrane.

Preparation and properties of functionalized carbon nanotube/PSF blend ultrafiltration membranes

Co-reporter:Shi Qiu, Liguang Wu, Xuejie Pan, Lin Zhang, Huanlin Chen, Congjie Gao

Journal of Membrane Science 2009 Volume 342(1–2) pp:165-172

Publication Date(Web):15 October 2009

DOI:10.1016/j.memsci.2009.06.041

Multi-walled carbon nanotubes (MWNTs) functionalized by isocyanate and isophthaloyl chloride groups were synthesized via the reaction between carboxylated carbon nanotubes and 5-isocyanato-isophthaloyl chloride (ICIC). Furthermore, blends of polysulfone (PSF) and functionalized MWNTs with different composition dissolved in dimethylformamide (DMF) were used to prepare ultrafiltration membranes by a classical phase-inversion method. It was found that the content of functionalized MWNTs was an important factor influencing the morphology and permeation properties of the blend membranes. The pure water flux of the blend membranes increased with the content of functionalized MWNTs, up to 0.19%, and then gradually decreased. The static water contact angle of the blend membrane surface showed that the hydrophilicity of the surface increased with the content of functionalized MWNTs in the blend. In addition, SEM images of the blend membrane surface and cross-section showed that the average pore size and pore structure of the blend membranes changed with the content of functionalized MWNTs up to 0.19%, and after that, the average pore size decreased. Finally, protein adsorption performance of membrane indicated that MWNT content suppressed the adsorption of protein on membrane, and thus alleviated membrane fouling.

Recovery of fumaric acid by hollow-fiber supported liquid membrane with strip dispersion using trialkylamine carrier

Co-reporter:Sheng-Ji Li, Huan-Lin Chen, Lin Zhang

Separation and Purification Technology 2009 Volume 66(Issue 1) pp:25-34

Publication Date(Web):7 April 2009

DOI:10.1016/j.seppur.2008.12.004

This paper presents the transport of fumaric acid (FA) from an aqueous feed solution through a hollow-fiber supported liquid membrane (HFSLM) with strip dispersion. Trialkylamine (N7301) was used as carrier. Many factors having strong impacts on the extraction characteristics of the system were studied in detail, including the characteristics of feed and strip solutions, the composition of membrane solvent phase and the operating conditions. Membrane solvents were chosen from different chemical classes (four “inert” solvents: o-xylene, toluene, benzene, n-dodecane; and three “active” solvents or co-solvents: polar solvent n-octanol, electron donating solvent methyl isobutyl ketone-MIBK, and electron accepting solvent chloroform). And the Hansen solubility parameter theory was applied to analyze the influence of different solvents on the transport of fumaric acid. At the optimum operating condition, the extraction of FA reached 89.5% and the total TOC removal rate was 96.5%. FA crystal was obtained by acidification of the sodium fumarate solution. The total mass transfer coefficient was modeled and the modeling result agreed well with the experimental result. After five consecutive transport studies without reimpregnation of the carrier, the extraction remained fairly constant and no significant loss of the membrane solution was observed.

Silicalite-Filled PEBA Membranes for Recovering Ethanol from Aqueous Solution by Pervaporation

Co-reporter:Jin Gu;Xuan Shi;Yunxiang Bai;Hongmang Zhang;He Huang

Chemical Engineering & Technology 2009 Volume 32( Issue 1) pp:155-160

Publication Date(Web):

DOI:10.1002/ceat.200800252

Abstract

Pervaporation (PV) performances of silicalite-filled polyether-block-amide (PEBA) membranes for separation of ethanol/water mixtures have been studied. The effects of silicalite content, ethanol concentration in feed, and feed temperature on the PV performances of the membranes have been investigated. It is found that addition of silicalite can improve PV performances of PEBA membranes. When the silicalite content is 2.0 wt %, both permeation flux and separation factor reach the maximum values, which are 833 g/m²h and 3.6, respectively. With increasing of ethanol in the feed and feed temperature, both separation factor and total flux increased. The higher permeation activation energy of ethanol (E_ethanol = 21.62 kJ/mol) compared to that of water (E_water = 18.33 kJ/mol) for the 2.0 wt% silicalite-filled PEBA membrane accounts for the increase of the separation factor with feed temperature.

Preparation of reverse osmosis composite membrane with high flux by interfacial polymerization of MPD and TMC

Co-reporter:Shi Qiu;Liguang Wu;Huanlin Chen;Congjie Gao

Journal of Applied Polymer Science 2009 Volume 112( Issue 4) pp:2066-2072

Publication Date(Web):

DOI:10.1002/app.29639

Abstract

In this study, reverse osmosis (RO) composite membrane with extra-thin separation layer was prepared by the interfacial polymerization (IP) of metaphenylene diamine (MPD) with trimesoyl chloride (TMC) on the surface of polysulfone (PS) support membrane. The properties and structures of skin layer of RO composite membranes were characterized by FTIR and SEM, it was found that IP had occurred and the separation layer was formed. The effects of the monomer concentration on membrane flux and salt rejection were investigated, and the optimum concentration of MPD and TMC were 2 and 0.3% (w/v), respectively. To improve flux, the phase-transfer catalyst was added to the water phase, and the effects were remarkable when the concentration of MPD was low, in which both salt rejection and flux increased by 20% than initial results. When some of the hydrophilic additives such as alcohols and phenols were added into water phase, the flux of the prepared membrane increased from 13.03 to 33.42 L/(m² h) without loss in salt rejection. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Immobilization of carbonic anhydrase by embedding and covalent coupling into nanocomposite hydrogel containing hydrotalcite

Co-reporter:Ya-Tao Zhang, Tian-Tian Zhi, Lin Zhang, He Huang, Huan-Lin Chen

Polymer 2009 50(24) pp: 5693-5700

Publication Date(Web):

DOI:10.1016/j.polymer.2009.09.067

Synthesis and characterization of poly(acrylic acid-co-acrylamide)/hydrotalcite nanocomposite hydrogels for carbonic anhydrase immobilization

Co-reporter:Ya-Tao Zhang;Li-Hai Fan;Tian-Tian Zhi;He Huang;Huan-Lin Chen

Journal of Polymer Science Part A: Polymer Chemistry 2009 Volume 47( Issue 13) pp:3232-3240

Publication Date(Web):

DOI:10.1002/pola.23367

Abstract

To combine the advantages of a biopolymer with hydrotalcite in an enzyme immobilization system, the intercalation polymerization was used to prepare poly(acrylic acid-co-acrylamide)/hydrotalcite (PAA-AAm/HT) nanocomposite hydrogels using sodium methyl allyl sulfonate as intercalation agent. Transmission electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy results revealed that sodium methyl allyl sulfonate chains entered into the interlayer of HT, the interaction between them has taken place, and HT was dramatically exfoliated into nanoscale and homogeneously dispersed in the PAA-AAm matrix. Transmission electron microscopy and cryo scanning electron microscope results showed that dried hydrogels were regular spherical particles, and swollen hydrogels revealed homogeneous porous network structures. Then, PAA-AAm/HT nanocomposite hydrogels were used to immobilize carbonic anhydrase (CA), and the CO₂ hydration activities of free enzyme and immobilized enzyme were evaluated. Results showed that immobilized CA retained the majority of the enzyme activity. The reason may be the formation of a microenvironment almost all of which is composed of free water inside the porous network structures. Therefore, the immobilized CA is of great potential in the removal of trace CO₂ from the closed spaces. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3232–3240, 2009

Preparation and morphology of high-performance exfoliated poly(sodium acrylate)/hydrotalcite nanocomposite superabsorbents

Co-reporter:Yatao Zhang;Lihai Fan;Lihua Cheng;Huanlin Chen

Polymer Engineering & Science 2009 Volume 49( Issue 2) pp:264-271

Publication Date(Web):

DOI:10.1002/pen.21252

Abstract

A poly-matrix composite—poly(sodium acrylate) (PSA)/hydrotalcite (HT) (PSA/HT) nanocomposite superabsorbent—with obvious improvements in both the water absorbency and salt absorbency has been prepared by the intercalated HT, using sodium methyl allyl sulfonate as an intercalation agent. The superabsorbents acquired their highest water (salt) absorbency when the content of HT is 3 wt%. The highest absorbency for deionized water and 0.9 wt% NaCl _(aq) were 1100 g/g and 145 g/g, respectively. Microstructures were analyzed by X-ray diffraction and scanning electron microscope. Chemical analysis was determined measurements. Results showed that HT incorporated into the superabsorbents was by Fourier infrared spectroscopy and energy dispersion spectroscopy. Results showed that the superabsorbent particles were in the form of spheres, and the hydrogels were in the form of regular network structures. POLYM. ENG. SCI., 2009. © 2008 Society of Plastics Engineers

Evaluation of a membrane-sparged helical tubular photobioreactor for carbon dioxide biofixation by Chlorella vulgaris

Co-reporter:Li-Hai Fan, Ya-Tao Zhang, Lin Zhang, Huan-Lin Chen

Journal of Membrane Science 2008 Volume 325(Issue 1) pp:336-345

Publication Date(Web):15 November 2008

DOI:10.1016/j.memsci.2008.07.044

A membrane-sparged helical tubular photobioreactor (MSTR) with a cultivation volume of 800 ml was designed in this study. It consisted of a cylindrical-shaped light receiver and a mass transfer system. A helical tube was used to ensure good light regime, and hollow fiber membranes were uniformly fitted inside the reactor, which functioned as a gas sparger and produced small bubbles. Mass transfer coefficients, mixing intensities and capabilities of CO2 biofixation through the photosynthesis of Chlorella vulgaris in MSTR under different gas, liquid flow rates and light intensities were compared with two other photobioreactors (BCTR and MCTR). BCTR took a perforated pipe as sparger, while MCTR employed a membrane contactor as the whole mass transfer system. To establish if the limitation of CO2 removal was improved in MSTR, pH, dissolved oxygen, cell damage, and characteristic times for mixing, mass transfer and CO2 consumption were analyzed during batch culture.

Recovery of Petroleum Ether from Solanesol Extracting Solution through Vacuum Hydrophilic Membrane Distillation

Co-reporter:Xin Y. Qu, Lin Zhang, De S. Tang, Zhi J. Zhou and Huan L. Chen

Industrial & Engineering Chemistry Research 2008 Volume 47(Issue 23) pp:9544-9551

Publication Date(Web):October 31, 2008

DOI:10.1021/ie071499+

The objective of this work is to study the feasibility of vacuum membrane distillation (VMD) by hydrophilic membranes to recover petroleum ether from the extracting solution of solanesol. Being different from the traditional membrane distillation (MD) process, hydrophilic membranes were used to avoid the membrane wetting for the nonaqueous solutions. The VMD performances of polyvinylidene fluoride (PVDF) membrane and two kinds of polyacrylonitrile (PAN) membranes with different structures were compared in the process of recovering petroleum ether. The results showed that good solvent flux (>15 kg/m2 h) and solanesol rejection (>98%) for the PAN membranes were obtained, indicating that PAN membranes had considerable potential use in this area, while the PVDF membrane was not appropriate for the nonaqueous solution system because of membrane wetting. The effects of operation conditions on VMD performances of the two PAN membranes were investigated, and it was found that high-feed temperatures, low-downstream pressures enhanced the permeate flux for both membranes, and the flux of PAN1 membrane decreased more obviously than that of PAN2 membrane under high-feed concentration because of its larger pore size. General models including Knudsen and viscous flows were proposed, and a good agreement between the experimental and the theoretical fluxes was obtained. Additionally, temperature and concentration polarizations were proved to have an obvious influence on mass transport of PAN1 membrane. It was advisable to work at the downstream pressure of 20 kPa, the feed temperature of 30 °C, and the feed flow rate of 27.5 mL/s to obtain favorable results for PAN2 membrane.

Effect of coagulation bath temperature on formation mechanism of poly(vinylidene fluoride) membrane

Co-reporter:Xuyun Wang;Dahai Sun;Quanfu An;Huanlin Chen

Journal of Applied Polymer Science 2008 Volume 110( Issue 3) pp:1656-1663

Publication Date(Web):

DOI:10.1002/app.28169

Abstract

Effects of coagulation bath temperature on the membrane formation mechanism and the morphologies of the formed membranes were studied. The binodal and spinodal lines in the phase diagrams of water/DMAc/Poly(vinylidene fluoride) (PVDF) were calculated based on the thermodynamics equations of membrane formation, and the gel phase boundaries of the systems at 25°C and 60°C were determined via cloud point measurement. The obtained ternary phase diagrams of water/DMAc/PVDF contain three regions: the one-phase region, the liquid–liquid two-phase region, and the gel region. In the phase diagrams, the liquid–liquid demixing line (binodal) is located inside the gelation line. At low temperature, there exists a wide region between gelation line and binodal line. Gelation could occur in the absence of liquid–liquid demixing, and becomes the dominant membrane formation mechanism. At high temperatures (60°C), however, the gelation line approaches the binodal line, which results in a much smaller gelation zone. The kinetics of the solvent out-flux and water influx were enhanced, liquid–liquid demixing is the dominant mechanism. The membrane formation mechanisms at different temperature were confirmed by the light transmission measurements during membrane forming process and the morphologies of the membranes examined by SEM imaging. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008.

Extraction and purification of solanesol from tobacco: (I). Extraction and silica gel column chromatography separation of solanesol

Co-reporter:De-Song Tang, Lin Zhang, Huan-Lin Chen, Yue-Rong Liang, Jian-Liang Lu, Hui-Ling Liang, Xin-Qiang Zheng

Separation and Purification Technology 2007 Volume 56(Issue 3) pp:291-295

Publication Date(Web):15 September 2007

DOI:10.1016/j.seppur.2007.01.040

Solanesol, a main polyprenol occurred in tobacco, has gained the attention of biochemists because of its value as a source of isoprene units for the synthesis of metabolically active quinones and vitamin K analogs. This article deals with extraction and purifyication of solanesol. Ground tobacco leaf was extracted with petroleum ether in 50 °C water bath under reflux for 2 h, and then filtrated, the powder leaf was re-extracted successively with petroleum ether and the extracts were pooled and concentrated to get pasty residue. The residue was saponified and subsequently loaded onto silica gel column chromatography. The chemical was eluted using a binary solvent mixture of petroleum ether–acetone (90:10, v/v) and the eluent was collected by fraction size of 5 ml. Tentative identification was carried out using TLC. The fractions mainly contained solanesol were pooled and dried by rotary evaporation. The yield of solenosol was 0.38% of the dry weight of tobacco leaf, and the purity was 83.04%.

Optimization of Carbon Dioxide Fixation by Chlorella vulgaris Cultivated in a Membrane-Photobioreactor

Co-reporter:L.-H. Fan;Y.-T. Zhang;L.-H. Cheng;L. Zhang;D.-S. Tang;H.-L. Chen

Chemical Engineering & Technology 2007 Volume 30(Issue 8) pp:

Publication Date(Web):20 JUL 2007

DOI:10.1002/ceat.200700141

In this paper, an enclosed membrane-photobioreactor was designed to remove CO₂ using Chlorella vulgaris. The performances of four reactors, which included the presented novel bioreactor, a draft tube airlift photobioreactor, a bubble column and a membrane contactor, were compared. The effects of the gas flow rate, light intensity, quality of the inner light source, and the characteristics of membrane module on CO₂ fixation were investigated. The results showed that the rate of CO₂ fixation in the membrane-photobioreactor was 0.95–5.40 times higher than that in the other three conventional reactors under the optimal operating conditions

Optimal design of nanofiltration system for surface water treatment

Co-reporter:Fei Bi, Haiyang Zhao, Zhijun Zhou, Lin Zhang, Huanlin Chen, Congjie Gao

Chinese Journal of Chemical Engineering (December 2016) Volume 24(Issue 12) pp:1674-1679

Publication Date(Web):1 December 2016

DOI:10.1016/j.cjche.2016.05.012

Both reverse osmosis (RO) and nanofiltration (NF) membranes have been increasingly used for water purification and desalination. However, the salt rejection of NF membranes is quite different from that of RO membranes, which makes a significant distinction in their process designs. This work started from the performance investigation of a single NF membrane element and then focused on the process design of the NF system for surface water treatment. In experimental tests, it was found that the observed rejection of the NF element becomes nearly constant when the concentrate flow is large enough, while the membrane flux of the NF element is quite stable regardless of the water flow across the membrane surface. These findings can be used to instruct the process design of the NF system for surface water treatment. In process design, a two-stage arrangement is sufficient for the NF system to reach the highest water recovery, while the RO system requires a three-stage arrangement.

Discussion on calculation of maximum water recovery in nanofiltration system

Co-reporter:Fei Bi, Haiyang Zhao, Lin Zhang, Qian Ye, Huanlin Chen, Congjie Gao

Desalination (2 January 2014) Volume 332(Issue 1) pp:142-146

Publication Date(Web):2 January 2014

DOI:10.1016/j.desal.2013.11.017

•A method has been proposed to calculate the maximum recovery for NF2 system.•Water recovery for a NF element should be lower than 25% to maintain it stable.•The CP degree was recommended to be 1.15 at the recovery of 25% in NF system.In desalination process, the effect of concentration factor (CF) and concentration polarization degree (CP degree) on water recovery in nanofiltration (NF) system displays a significant difference from that in reverse osmosis (RO) system due to their different salt rejections. In this work, the relationship between CF, salt rejection and water recovery was firstly discussed in a single NF element. In order to keep a stable performance, a spiral NF2 membrane was taken as an example, and water recovery for the single NF2 element should be about 25% instead of 15%, which is generally considered suitable for the single RO element. Then, the CP degree was calculated according to the theoretical model and experimental test, and the ultimate value was pointed out to be below 1.2. Thus, when calculating the scaling tendency of the sparingly soluble salts, the salt concentration near the membrane surface was recommended to be 1.15 times as high as that in bulk solution. Finally, a calculation method for maximum recovery was proposed for NF system. Because of the varied rejection with different NF membranes for the same feed water, which is significantly different from that in RO system, the pre-test is very necessary for NF system design.

Extraction and purification of solanesol from tobacco: (I). Extraction and silica gel column chromatography separation of solanesol

Co-reporter:De-Song Tang, Lin Zhang, Huan-Lin Chen, Yue-Rong Liang, Jian-Liang Lu, Hui-Ling Liang, Xin-Qiang Zheng

Separation and Purification Technology (15 September 2007) Volume 56(Issue 3) pp:291-295

Publication Date(Web):15 September 2007

DOI:10.1016/j.seppur.2007.01.040

A comprehensive review of vacuum membrane distillation technique

Co-reporter:Mostafa Abd El-Rady Abu-Zeid, Yaqin Zhang, Hang Dong, Lin Zhang, Huan-Lin Chen, Lian Hou

Desalination (15 January 2015) Volume 356() pp:1-14

Publication Date(Web):15 January 2015

DOI:10.1016/j.desal.2014.10.033

•The vital role of VMD for the water shortage and energy crisis is demonstrated.•The advantages of VMD in exploiting solar energy are reported.•The different application areas for VMD are presented.•The integrated processes of VMD and other technologies are introduced.•Several classical models about heat and mass transfer in VMD process are given.The purpose of this review is to provide an overview of the vacuum membrane distillation (VMD) process in regard to its advantages, disadvantages and miscellaneous implementations, particularly in the solar energy field. Based on its advantages, a prominent role of VMD configuration in alleviating and tackling a sharp potable water shortage problem is presented, and multiple applications of a VMD hollow-fiber membrane module are exhibited in detail. The impact of different operating parameters on VMD output is dissected, and the diversified membrane characteristics are pointed out. Eventually, the mechanism model of the VMD heat and mass transfer is demonstrated.

Improving the performance of the air gap membrane distillation process by using a supplementary vacuum pump

Co-reporter:Mostafa Abd El-Rady Abu-Zeid, Lin Zhang, Wang-Yong Jin, Tao Feng, Yier Wu, Huan-Lin Chen, Li'an Hou

Desalination (15 April 2016) Volume 384() pp:31-42

Publication Date(Web):15 April 2016

DOI:10.1016/j.desal.2016.01.020

•The performance of AGMD significantly improved by using a supplementary vacuum pump.•The permeate flux, performance ratio, gained output ratio and thermal efficiency increased by 24.96, 15.25, 14.29 and 11.99%, respectively, from AGMD to V-AGMD.•Compared with AGMD, the energy consumption of V-AGMD didn’t increase.In this study, the process of air gap membrane distillation (AGMD) supplemented by a vacuum pump was developed to eliminate the disadvantage of the air gap and to improve the process performance. The vacuum-air gap membrane distillation (V-AGMD) process was evaluated by comparing with the AGMD process while varying operating conditions such as the feed inlet temperature, feed flow rate, cooling water temperature and feed salt concentration. The optimal operating conditions were obtained by orthogonal experiments of the AGMD and V-AGMD processes. It was found that the vacuum pump could promote the permeate flux (PF), thermal efficiency (η), gained output ratio (GOR) and performance ratio (PR). Under the optimal conditions, a feed flow rate of 4 l/min and feed inlet temperature of 50 °C, PF and GOR could be increased by 24.96% and 14.29%, respectively, from AGMD to V-AGMD. While the feed inlet temperature at 80 °C, cooling water temperature at 20 °C and feed salt concentration at 253 ppm, PR and η increased about 15.25% and 11.99% at 2 l/min and 4 l/min, respectively. The results of this work proved that improving the performance of the AGMD process is possible by using a supplementary vacuum pump.

A cross-linking graphene oxide–polyethyleneimine hybrid film containing ciprofloxacin: one-step preparation, controlled drug release and antibacterial performance

Co-reporter:Tiefan Huang, Lin Zhang, Huanlin Chen and Congjie Gao

Journal of Materials Chemistry A 2015 - vol. 3(Issue 8) pp:NaN1611-1611

Publication Date(Web):2014/12/30

DOI:10.1039/C4TB01896F

Improving the antifouling property of polysulfone ultrafiltration membrane by incorporation of isocyanate-treated graphene oxide

Co-reporter:Haiyang Zhao, Liguang Wu, Zhijun Zhou, Lin Zhang and Huanlin Chen

Physical Chemistry Chemical Physics 2013 - vol. 15(Issue 23) pp:NaN9092-9092

Publication Date(Web):2013/04/08

DOI:10.1039/C3CP50955A

Acid and multivalent ion resistance of thin film nanocomposite RO membranes loaded with silicalite-1 nanozeolites

Co-reporter:Hai Huang, Xinying Qu, Xiaosheng Ji, Xin Gao, Lin Zhang, Huanlin Chen and Lian Hou