Sharif Digital Repository

In this work, sulfonated polycarbonate (SPC ) membranes with different acid contents have been prepared by conducting sulfonation reaction at room temperature using Chlorosulfonic acid (CSA) as sulfonating agent at different concentration of acid in reacting solution. The SPC membranes were obtained by casting from 10% solution of SPC in chloroform at room temperature. The prepared membranes were characterized using Ion exchange capacity (IEC), and degree of sulfonation (DS), Fourier Transform Infrared (FTIR), NMR spectra, Thermal Gravimetric Analysis (TGA) and Water uptake. The obtained results showed that with increaseing in Chlorosulfonic acid content in sulfonation reaction IEC and DS of... 

Today, energy crises and the environmental pollution have become serious problems for the human being. To address these problems, extensive efforts have been made to replace fossil fuels with other clean energy resources such as fuel cells. In the meantime, polymer electrolyte fuel cells are very important as they are now commonly used in the field of transportation, and their importance become even more obvious as we consider the fact that the by-products from electricity production by such cells are simply water and heat. This research studies the efficiency of the polymer called “polysulfone” as an electrolyte fuel cell, which has the above named mechanical thermal and chemical... 

In Hemodialysis, membrane dialyser and commonly hollow fibers are used to treat patients who suffer from end stage renal failure. When blood flows into membrane, it loses uremic toxins such as urea and creatinine. On the other hand, some of the vital proteins of blood pass through the membrane or they are adsorbed on the membrane surface. The more hydrophilicity of the membrane, the less adsorption of proteins is. In this study, to achieve high hydrophilicity and low adsorption of proteins on the polysulfone membrane surface, the presence of hydrophilic nano-particles SBA-15 in membrane composition is investigated. The nano-particles with mass percentages 0.25%, 0.5 % and 1 % to one mass of... 

There are different types of sensors for measuring the concentration of gases that usually have high prices because of their complicated method of production. We can produce much cheaper sensors in special conditions by using polymer membranes. Different gases can be separated by using appropriate polymer membranes and the difference between diffusion rate of these gases is the basis of the separation method and gases pass through the membrane with different flow rates in the specific entrance pressure. The flow rate of total gas which flows will be different for a binary gaseous mixture at specific temperature and pressure with different concentrations because the flow rate is relative to... 

Low frequency (LF) O2 plasma was used to modify the surface of polysulfone (PSF) gas separation membranes. The effect of treatment time and plasma power input on the membranes was also investigated. Pure CO2 and CH4 gas permeation measurements were performed before and after plasma treatment. The results showed the increase of permeability of the treated membranes due to surface ablation and surface polarization. However, the CO2/CH4 permselectivity of the treated membranes varied from 7.7 to 45.3 depending on the treatment conditions. Attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy determined the introduction of oxygen containing polar groups on the surface... 

A new technique for surface modification of flat sheet hemodialysis membranes has been investigated. This new strategy presents a dynamic surface modification for membranes in order to assess the hydrophilicity, antifouling, and biocompatibility effects of two functional monomers on dialysis membrane. PSF membranes containing polyvinylpyrrolidone were prepared via phase inversion technique. Afterward, free radical polymerization combined with surface polymerization used to introduce acrylic acid and 2-hydroxyethyl methacrylate onto polysulfone membrane surface. Various monomer concentrations were selected to obtain an optimum condition. Field emission scanning electron microscope (FE-SEM),... 

Recently separation technology has been developed and engineers are trying to find more rapid and more economic ways in order to reach pure materials. One of the most important needs of human being is natural gas which has some impurities. Acid gases such as carbon dioxide and hydrogen sulfide must be separated from methane. This operation is called gas sweetening. Membrane contactors are equipments recently developed and may be used instead of packed towers for gas sweetening in the future. In this project we designed and made a membrane contacting unit to separate carbon dioxide and hydrogen sulfide from methane. This unit lets you to study the effect of many parameters such as gas and... 

In this research, modification of polysolfune ultrafiltration membranes is investigated. The enhancement is done via grafting of the acrylic acid as a hydrophilic monomer on the membrane surface. This is a free radical grafting method in which free radicals are formed via redox reaction of ammonium persulfate and sodium metabisulfite as an initiator. Water contact angle, molecular weight cut-off, pure water flux and fouling experiments were used to figure out the optimum conditions for the membrane performance. In addition, scanning electron microscopy (SEM) and atomic force microscopy (AFM) were utilized to determine morphological changes of the membrane surface. Furthermore, Fourier... 

This study aims to investigate polysulfone (PSF) hollow fiber mixed matrix membranes (MMMs) properties containing Uio-66-NH2 and Mil-125-NH2 nanoparticles, groups of metal-organic frameworks (MOFs), for hemodialysis application. The nanoparticles were synthesized, and the membranes were produced by the phase inversion method. Membranes characterization conducted by ATR-FTIR, FE-SEM, EDX, TEM, and AFM was confirmed the presence of MOFs nanoparticles. Also, the evaluation of specific surface area of nanoparticles was done by BET. The water contact angle (WCA) results indicated the improvement of MMMs hydrophilicity, enhancing the pure water flux from 46.8 L/ m2h for the pristine membrane to... 

One of the major environmental problems in recent years is the presence of micropollutants that cause many problems for the environment and living organisms. Diclofenac is one of the micropollutants and endocrine disruptors. Conventional treatment methods do not have the ability to effectively remove pharmaceutical pollutants and micro-pollutants, and finding a suitable approach to remove these pollutants is of great importance. In recent years, biological methods such as the use of enzymes and molds have received attention, but due to the relative removal of pollutants, these methods have been combined with membrane technology to improve the level of pollutant removal and increase the...