Seyed Mahmoud Mousavi

Dynamic prediction of milk ultrafiltration performance: A neural network approach

Neural network models were tested in connection with the dynamic prediction of permeate flux (JP), total hydraulic resistance (RT) and the solutes rejection for the crossflow ultrafiltration of milk at different transmembrane pressure (TMP) and temperature (T). This process has complex non-linear dependencies on the operating conditions. Thus it provides demanding test of the neural network approach to the process variables prediction. Two neural network models with single hidden layer were constructed to predict the time dependent rate of JP/RT and rejections from a limited number of training data. The modelling results showed that there is an excellent agreement between the experimental data and predicted values, with average errors less than 1%. The experimental results showed that the RT and solutes rejection (except for protein) increased greatly with time at each value of TMP and T, whereas the JP decreased significantly for the same conditions. Increasing TMP at constant T led to an increase in the JP, RT and solutes rejection, but increasing T at constant TMP had no significant effect on the JP, RT and rejection of components.

Effects of Curvature Ratio and Coil Pitch Spacing on Heat Transfer Performance of Al2O3/Water Nanofluid Laminar Flow through Helical Coils

In the present work, the influence of curvature ratio and coil pitch for Al2O3/water nanofluid laminar flow on heat transfer behavior and pressure drop through helical coils were investigated experimentally. These experiments were performed for coils with curvature ratio 10 and 20 plus coil pitch 24 and 42. The volume fractions of nanoparticles were 0.25–1.0%. Nanofluids at all concentrations showed much higher heat transfer rate and pressure drop in comparison with distilled water, which is due to the nanoparticles present in the fluid. In addition, due to curvature of coils, significant enhancement was observed in heat transfer rate as well as pressure drop when helical coils utilize instead of straight one. Moreover, the heat transfer rate improved with the increase of pitch coils and decrease of curvature ratio. Also, the Nusselt numbers for nanofluid flow inside coils was correlated with helical number, Prandtl number, and volume concentration of nanofluid.

Preparation of modified polyethersulfone membranes using variation in coagulation bath temperature and addition of hydrophilic surfactant

In this study, novel asymmetric polyethersulfone membranes were prepared from PES/PEG/Tween-20/NMP system via immersion precipitation. Pure water was used as gelation media. Simultaneous effects of variation in coagulation bath temperature (CBT) and addition of Tween-20 on morphology, wettabiliy, pure water permeation flux (PWF) and bovine serum albumin (BSA) rejection of the prepared membranes were studied by scanning electron microscopy (SEM), atomic force microscopy (AFM), contact angle measuring instrument and experimental set up. The obtained results indicate that the small addition of surfactants in the casting solution along with using the lowest level of CBT increases hydrophilicity of the PES membranes. Also it was found out that addition of Tween-20 in the casting solution along with increasing the CBT incites the formation of the bigger pores on the top surface and results in the formation of membranes with higher porosity in the sublayer.

Modeling of arsenic, chromium and cadmium removal by nanofiltration process using genetic programming

In this paper, genetic programming (GP) as a novel approach for the explicit formulation of nanofiltration (NF) process performance is presented. The objective of this study is to develop robust models based on experimental data for prediction the membrane rejection of arsenic, chromium and cadmium ions in a NF pilot-scale system using GP. Feed concentration and transmembrane pressure were considered as input parameters of the models. The ions rejection is considered as output parameter of the models. Some statistical parameters were considered and calculated in order to investigate the reliability of each model. The results showed quite satisfactory accuracies of the proposed models based on GP. The results also nominated GP as a potential tool for identifying the behavior of a NF system.

Preparation and characterization of poly (ethersulfone) nanofiltration membranes for amoxicillin removal from contaminated water

Nowadays, antibiotics such as amoxicillin have been entered in water bodies. Nanofiltration has been proposed as an attractive technology for removal of antibiotics from aquatic environment instead of conventional wastewater treatment. In this paper, novel asymmetric flat sheet nanofiltration membranes were prepared via immersion precipitation technique and by using the poly(ethersulfone)/Brij®S100/Poly(vinylpirrolidone)/1-methyl-2-pyrolidone casting solutions. The effect of addition of Brij®S100 as a non-ionic surfactant additive as well as concentration of poly (ethersulfone) on morphology, wettability, pure water flux and rejection of amoxicillin were studied using the scanning electron microscopy, water contact angle apparatus and experimental set-up. The results indicated that the addition of Brij®S100 to the casting solutions resulted in the formation of membranes with higher hydrophilicity and relatively noticeable rejection of amoxicillin up to 99% in comparison with unmodified poly(ethersulfone) membrane. Contrary to amoxicillin rejection, pure water flux was decreased when higher poly(ethersulfone) concentration was employed.

Cellulose acetate butyrate membrane containing TiO2 nanoparticle: Preparation, characterization and permeation study

Cellulose acetate butyrate/TiO2 hybrid membranes were prepared via phase inversion by dispersing the TiO2 nanoparticles in casting solutions. The influence of TiO2 nanoparticles on the morphology and performance of membranes was investigated. The scanning electron microscope images and experiments of membrane performance showed that the membrane thickness and pure water flux were first increased by adding the TiO2 nanoparticles to the casting solution up to 4 wt% and then decreased with the addition of further nanoparticles to it. The obtained results indicated that the addition of TiO2 in the casting solution enhanced the rejection and permeate flux in filtration of bovine serum albumin solution. Furthermore, increasing the TiO2 nanoparticle concentration in the casting solution increased the flux recovery and consequently decreased the fouling of membrane.

Extraction of Arsenic(V) from Water Using Emulsion Liquid Membrane

In this article, the extraction of arsenic(V) from water by means of emulsion liquid membrane is investigated. The influence of operating factors such as stirring speed, concentration of sulfuric acid in the external aqueous phase, concentration of sodium sulfate in internal stripping phase, and concentration of carrier in the membrane phase on the extraction efficiency are investigated and their optimum values, which provide the maximum recovery of arsenic, are determined. Taguchi experimental design is used in order to reduce the number of experiments. The optimum amounts for the extraction of arsenic from water, based on the results, are: stirring speed, 500 rpm; concentration of sulfuric acid in the feed, 1.5 g mol/lit; concentration of reagent in internal phase, 1.5 g mol/lit; and concentration of carrier in 3 ml kerosene which is added to the membrane phase, 0.1 g mol/lit.

Development of High Performance Nanofiltration Membranes with Hydrophilic Surface for the Removal of Cadmium from Contaminated Water

In present research, novel asymmetric polysulfone (PSF) membranes with high hydrophilicity and noticeable rejection of cadmium, as one of the major environmental problems, were prepared from PSF/PEG400/NMP system via immersion precipitation. Pure water was used as gelation media. The variation effect of the coagulation bath temperature (CBT) and addition of PEG400 on morphology, wettability, and permeability of the prepared membranes were studied by scanning electron microscopy (SEM), contact angle measuring, and the experimental set up. The results demonstrated that both the hydrophilicity and the rejection properties of the prepared membranes were significantly enhanced by a small addition of PEG400 in the casting solution along with using the lowest level of CBT. Also, it was found out that the addition of PEG400 in the casting solution along with increasing the CBT resulted in the formation of membranes with high permeability and sub-layer porosity and thin top layer.

Ultrasound assisted preparation of water in oil emulsions and their application in arsenic (V) removal from water in an emulsion liquid membrane process

Water in oil emulsions are prepared by using an ultra-sonication device and used in an emulsion liquid membrane process in order to recover arsenic (V) ions from an aqueous medium. The aim of this work is the investigation of the effect of emulsifier concentration and composition, and also sonication time on the emulsion droplet size and the extraction efficiency in order to obtain stable emulsions with small droplets that favor the extraction. Results show that ultrasonic waves reduce internal droplet size which enhances the extraction of arsenic. In addition, internal droplet size is decreased initially and then increased by increasing Span 80 concentration. On the other hand, by increasing Span 80 concentration, extraction amount is increased and then decreased. Furthermore, emulsifier blends provide more stability for the emulsion. Increasing concentration of Tween 20 as a hydrophilic emulsifier up to an optimum concentration decreases internal droplet size and increases extraction amount. By increasing sonication time up to 4 min, the internal droplet size is decreased and the extraction amount is increased. If sonication time is increased further, the internal droplet size is increased and the extraction amount is decreased.

Preparation of hydrophilic nanofiltration membranes for removal of pharmaceuticals from water

Asymmetric polyethersulfone (PES) nanofiltration membranes were prepared via phase inversion technique. PES polymer, Brij 58 as surfactant additive, polyvinylpyrrolidone (PVP) as pore former and 1-methyl-2-pyrrolidone (NMP) as solvent were used in preparation of the casting solutions. Distillated water was used as the gelation media. The scanning electron microscopy (SEM) images and measurements of contact angle (CA) and zeta potential were used to characterize the prepared membranes. Also performance of the membranes was examined by determining the pure water flux (PWF) and pharmaceuticals rejection. The addition of Brij 58 to the casting solution resulted in formation of the membranes with higher thickness and more porous structure in the sublayer in comparison with the net PES membrane. The surface hydrophilicity of the membranes was remarkably enhanced via the presence of Brij 58 in the casting solution, so that, the contact angel diminished from 74.7° to 28.3° with adding 6 wt. % of Brij 58 to the casting solution. The addition of Brij 58 to the casting solution resulted in formation of the membranes with superior PWF and higher rejection of amoxicillin and ceftriaxone in comparison with the pure PES membrane.