Sharif Digital Repository

Water treatment from industrial and domestic pollutants is one of the most important issues in recent decades. In the present research, simulation of water purification using single-layer graphene membrane were studied. The effects of nanopores diameter, applied pressure, concentration of contaminant ions, and functional groups on the amount of filtered water and ion rejection through the membrane were quantified. Contaminant ions including Na+, K+, Mg2+, Ca2+, and Cl- were dissolved in water. Based on the results, by increasing the pore diameter and applied pressure, more water would pass through the membrane. Also it was concluded that pores with functional groups have better performance... 

Chlorinated hydrocarbons such as trichloroethylene form a kind of dense non-aqueous phase liquid contaminants in groundwater and soil that are so difficult to remediate. In recent years, many field research has been demonstrated application of nano scale zero valent iron can degrade these contaminants.
In this research, nZVI particle synthesized by liquid phase reduction method. Nickel (25%wt ) has been added to increase the reduction rate and also reduce intermediate pollutions. However, the combination of a noble metal to nZVI, leads to more rapid oxidation and tendency to agglomeration. So nZVI particles coated by applying a water soluble-starch solution (0.4%wt) as a stabilizer. The... 

Bimetallic nanoparticles with unique structure, synergistic effect between two metals, and the tunable physical/chemical properties have been used for catalysis. Various methods exist for the staibility, and improvement of the catalytic performance of nanoparticles. In this thesis, different co-catalysts were applied to increase tha staibility, and activity of nanoparticles and metal oxides. In this way, Ni-based bimetallic nanoparticles including CuNi, CoNi, and AgNi, and AgPt with different concentrations were synthesized on the cerium oxide nanorods derived from cerium metal-organic frameworks and magnetic graphene oxide nanosheets, respectively and characterized. The catalytic... 

In this study preparation of polymeric membrane for grey water treatment is examined. Grey water is the wastewater that is produced by household activities such as baths, showers and sinks. These sources make 50 to 80 percent of total household wastewater. Because of low contamination of these kind of wastewater, they can be treated with Nanofiltration membrane process. Membrane used for treatment is thin composite polyamide membrane. This membrane is made with interfacial polymerization reaction of Piperazine and m-phenylenediamine as amine monomer and trimesoyl chloride as chloride acid monomer on a Polysulfone ultrafiltration membrane. In order to promote the flux, Polyethylene glycol is... 

In this project, transport and absorption of magnetic particles for the purpose of water purification has been simulated. The used magnetic particles must be collected; otherwise they would cause additional pollution. Therefore, separation and absorption of particles is vital. The particles can be collected with an applied magnetic field. In this study different kinds of magnetic fields are applied and effect of different parameters, such as particle diameter, Reynolds number and magnetic field are considered. By increasing particle diameter and magnetic filed strength, the absorption efficiency increases. But by increasing Reynolds number absorption efficiency decreases. The particle with... 

Poly vinylidene fluoride (PVDF) as a fluorine polymer with acceptable thermal, chemical and physical property attractive create attention in membrane technology for water treatment application. However, with differential surface free energy between PVDF and water (∆G_s=30 mJ/m^2) PVDF polymer is divided as a hydrophobic materials, that is one of the basic problem for PVDF polymer. Due to its hydrophobicity the water molecules repulsion away from hydrophobic PVDF membrane surface as a spontaneous process with an entropy increasing and therefore pollutant molecules with hydrophobic functional group have tendency to adsorb onto membrane surface and dominate the boundary layer. In recent years... 

Novel zeolite-based micromotors consisted of silver-exchanged zeolite core and three different partial catalytic coatings (Mg/Au, Pt and Ag) were synthesized to eliminate the biological and chemical contamination from water in a fast and efficient way. These engines are benefited by the adsorption capacity and antibacterial activity of silver-zeolites in combination with the autonomous propulsion of catalytic micromotors. The remarkable bactericidal capacity of these particles relies on reactive silver ion released from zeolite and accordingly, increased chance of contact with bacteria during movement. These motors showed rapid killing of bacteria and effective elimination of the Pseudomonas... 

Contaminants in drinking water, including microbial contaminants, have a great impact on the health of people in the community and can seriously threaten public health. In recent years, diseases caused by pathogenic bacteria due to the consumption of contaminated water have led to many deaths. As a result, water treatment has been one of the most important human concerns. Among the new water treatment technologies, metal-organic(MOF) frameworks are a new generation of porous materials that have properties such as high surface area, water stability and functionality due to their dual structure. As a result, they are widely used today in various scientific fields, including water purification.... 

The N-doped rGO/NiFe2O4@Ti-doped ZnO as a novel ternary nanocomposite with magnetic recyclable was obtained by a facile and low-cost hydrothermal method. The structure, morphology, and optical as well as magnetic properties of synthesized nanocomposite were analyzed using the X-ray diffraction (XRD), Fourier-transform infrared spectra (FTIR), Raman spectroscopy, Emission scanning electron microscopy (FESEM) with Energy dispersive spectra, Transmission electron microscopy (TEM), UV-vis diffusive reflectance spectra, and Vibrating sample magnetometer (VSM). The photocatalytic activity was determined by the degradation of Methylene blue (MB) and Methylene orange (MO) dyes under visible light... 

In the past decades, hydrogels have been used as an adsorbent with high potential to remove pollutants in water. Hydrogels are three-dimensional polymer networks that have the ability to absorb and store water and water-soluble compounds due to the presence of hydrophilic functional groups in their structure. Different particles with unique characteristics can be used to increase the efficiency of hydrogel absorption. Based on the type of pollutant, hydrogels are divided into three different forms, including particles, films and nanocomposites. In this research, the absorption effect of metal cations as well as the absorption kinetics of polyvinyl pyrrolidine-based hydrogels, sodium...