Abstract
In this work, oil-in-water emulsions (O/W) were prepared successfully by membrane emulsification with 0.5 μm pore size membrane. Sunflower oil was emulsified in aqueous Tween80 solution with a simple crossflow apparatus equipped with ceramic tube membrane. In order to increase the shear-stress near the membrane wall, a helical-shaped reducer was installed within the lumen side of the tube membrane. This method allows the reduction of continuous phase flow and the increase of dispersed phase flux, for cost effective production. Results were compared with the conventional cross-flow membrane emulsification method. Monodisperse O/W emulsions were obtained using tubular membrane with droplet size in the range 3.3-4.6 μm corresponded to the membrane pore diameter of 0.5 μm. The final aim of this study is to obtain O/W emulsions by simple membrane emulsification method without reducer and compare the results obtained by membrane equipped with helix shaped reducer. To indicate the results statistical methods, 3p type full factorial experimental designs were evaluated, using software called STATISTICA. For prediction of the flux, droplet size and PDI a mathematical model was set up which can describe well the dependent variables in the studied range, namely the run of the flux and the mean droplet diameter and the effects of operating parameters. The results suggested that polynomial model is adequate for representation of selected responses.
Address
(1) K. Albert, Gy. Vatai, A. Koris:
Szent István University, Faculty of Food Science, Department of Food Engineering, 1118 Budapest, Ménesi st. 44, Hungary; (2) L. Giorno:
Istituto per la Tecnologia delle Membrane, Consiglio Nazionale delle Ricerche, ITM-CNR, Via P. Bucci 17/C, 87030 Rende (CS), Italy.
Abstract
Boron is one of the most problematic inorganic pollutants and is difficult to remove in water. Strict standards have been imposed for boron content in water because of their high toxicity at high concentrations. Technologies using membrane processes such as reverse osmosis (RO) and nanofiltration (NF) have increasingly been employed in many industrial sectors. In this work, removal of boron from model water solutions was investigated using polyamide reverse osmosis and nanofiltration membranes. RO-AG, RO-SG, NF-90 and NF-HL membranes were used to reduce the boron from model water at different operational conditions. To understand the boron separation properties a characterization of the four membranes was performed by determining the pure water permeability, surface charge and molecular weight cut-off. Thereafter, the effect of feed pressure, concentration, ionic strength, nature of ions in solution and pH on the rejection of boron were studied. The rejection of boron can reach up to 90% for the three membranes AG, SG and NF-90 at pH = 11. The Spiegler-Kedem model was applied to experimental results to determine the reflection coefficient of the membrane
Key Words
boron; RO/NF membrane; Spiegler-Kedem model; mass transfer
Address
Desalination and water Treatment research unit, Faculty of Sciences of Tunis, Tunis El Manar University, El Manar II, 2092, Tunisia.
Abstract
As a highly hydrophilic fibrillar mineral in nature, attapulgite (ATP) is a promising new additive for preparation of ultrafiltration (UF) hybrid membrane. In this work, ATP particles, which were grafted with a new Gemini surfactant of Ethyl Stearate-di(octadecyl dimethyl ammonium chloride) to detach the crystal bundles to single crystal and enhance the uniform dispersion in an organic polymer matrix, were incorporated into poly(vinylidene fluoride) (PVDF) matrix, and PVDF/Gemini-ATP hybrid membranes for adsorptive removal of Ni(II) ions from aqueous solution were prepared via a phase inversion method. Chemical composition, crystalization and morphology of the modified ATP were characterized by Fourier transform infrared spectroscopy (FTIR), Transmission electron microscope (TEM) and X-ray diffraction (XRD), respectively. The morphology of the hybrid membrane was characterized by Scanning electron microscopy (SEM), the performance of permeability, hydrophilicity and adsorption of Ni(II) ions were studied, and the adsorption kinetics of the PVDF/ATP hybrid membranes were particular concerned. The results showed that the hybrid membrane displayed a good thermal stability and hydrophilicity. Comparing with PVDF membrane, the hybrid membrane possessed good adsorption capacity for Ni(II) ions, and the adsorption kinetics fit well with Lagergren second-order equation.
Key Words
PVDF; attapulgite; hybrid membrane; Gemini surfactant; adsorption; Ni(II)
Address
State Key Laboratory of Separation Membranes and Membrane Processes, School of Materials Science and Engineering, Tianjin Polytechnic University, Tianjin 300387, China.
Abstract
In this study, poly(vinyl-alcohol) and water insoluble β-cyclodextrin polymer (β-CDP) cross-linked with citric acid, have been used as macrocyclic carrier in the preparation of polymer inclusion membranes (PIMs) for aniline (as molecule model) extraction from aqueous media. The obtained membranes were firstly characterized by X-ray diffraction, Fourier transform infrared and water swelling test. The transport of aniline was studied in a two-compartment transport cell under various experimental conditions, such as carrier content in the membranes, stirring rate and initial aniline concentration. The kinetic study was performed and the kinetic parameters were calculated as rate constant (k), permeability coefficient (P) and flux (J). These first results demonstrated the utility of such polymeric membranes for environmental decontamination of toxic organic molecules like aniline. Predictive modeling of transport flux through these materials was then studied using design of experiments; the design chosen was a two level full factorial design 2k. An empirical correlation between aniline transport flux and independent variables (Poly β-CD membrane content, agitation speed and initial aniline concentration) was successfully obtained. Statistical analysis showed that initial aniline concentration of the solution was the most important parameter in the study domain. The model revealed the existence of a strong interaction between the Poly β-CD membrane content and the stirring speed of the source solution. The good agreement between the model and the experimental transport data confirms the model's validity.
Key Words
polymer inclusion membranes (PIMs); insoluble β-cyclodextrin polymer; aniline; design of experiment; statistical analysis
Address
(1) F. Oughlis-Hammache, M. Skiba, F. Hallouard, M. Lahiani-Skiba:
Pharmaceutical Technology and Biopharmaceutics Laboratory, Faculty of Medicine and Pharmacy, Rouen University, 22 Bd Gambetta, 76183 Rouen, France; (2) F. Oughlis-Hammache:
Université du 20 Août 1955-Skikda; (3) F. Oughlis-Hammache, L. Moulahcene, O. Kebiche-Senhadji, M. Benamor:
Laboratoire des Procédés Membranaires et des Techniques de Séparation et de Récupération (LPMTSR), Faculté de Technologie, Université A. Mira de Béjaia — Algérie; (4) F. Hallouard:
In-Cyclo, 75 Route de Lyons, 76183 Rouen, France.
Abstract
The enantiomeric and racemic effects of tartaric acid (TA) on the properties of polysulfone (PSn) ultrafiltration membranes were studied in terms of morphology and hydrophilicity (HPCT) of membrane. Asymmetric membranes were prepared by direct blending of polyvinyl pyrrolidone (PVP) with D-TA and DL-TA in membrane casting solution. FTIR analysis was done for the confirmation of the reaction of PVP and TA in blended membranes and plain PSn membranes. Scanning electron microscope (SEM), field emission scanning electron microscope (FESEM) and atomic force microscopy (AFM) were used for analyzing the morphology and structure of the resulting membranes. The membranes were characterized in terms of pure water flux (PWF), hydraulic permeability and HPCT. PWF increased from 52 L/m2h to 79.9 L/m2h for plain and D-TA containing PSn membrane, respectively. Water contact angle also found to be decreased from 68° to 55°. In Additionally, permeation and rejection behavior of prepared membranes was studied by bovine serum albumin (BSA) solution. A considerable increase in BSA flux (from 19.1 L/m2h for plain membrane to 32.1 L/m2h for D-TA containing membrane) was observed. FESEM images affirm that the pore size of the membranes decreases and the membrane permeability increases from 0.16 to 0.32 by the addition of D-TA in the membrane. D-TA increases the HPCT whereas; DL-TA decreases the HPCT of PSn membrane. PVP (average molecular weight of 40000 Da) with D-TA (1 wt%) gave best performance among all the membranes for each parameter.
Key Words
arsenic removal; contaminated water; hydrophobic membrane; membrane distillation
Abstract
The enantiomeric and racemic effects of tartaric acid (TA) on the properties of polysulfone (PSn) ultrafiltration membranes were studied in terms of morphology and hydrophilicity (HPCT) of membrane. Asymmetric membranes were prepared by direct blending of polyvinyl pyrrolidone (PVP) with D-TA and DL-TA in membrane casting solution. FTIR analysis was done for the confirmation of the reaction of PVP and TA in blended membranes and plain PSn membranes. Scanning electron microscope (SEM), field emission scanning electron microscope (FESEM) and atomic force microscopy (AFM) were used for analyzing the morphology and structure of the resulting membranes. The membranes were characterized in terms of pure water flux (PWF), hydraulic permeability and HPCT. PWF increased from 52 L/m2h to 79.9 L/m2h for plain and D-TA containing PSn membrane, respectively. Water contact angle also found to be decreased from 68° to 55°. In Additionally, permeation and rejection behavior of prepared membranes was studied by bovine serum albumin (BSA) solution. A considerable increase in BSA flux (from 19.1 L/m2h for plain membrane to 32.1 L/m2h for D-TA containing membrane) was observed. FESEM images affirm that the pore size of the membranes decreases and the membrane permeability increases from 0.16 to 0.32 by the addition of D-TA in the membrane. D-TA increases the HPCT whereas; DL-TA decreases the HPCT of PSn membrane. PVP (average molecular weight of 40000 Da) with D-TA (1 wt%) gave best performance among all the membranes for each parameter.
