فهرست مطالب moslem mansour lakouraj

In this paper, polyaniline nanostructurs with different morphologies were synthesized in medium containing ionic liquids (ILs) such as, imidazolium buthyl sulfonate [IMBS], pyridinium chloro acetic acid [PyCAA][Cl] and pyridinium hydrogen sulfate [HPy][HSO4] with various weight ratios of aniline/ILs. Structure and properties of synthesized polyanilines were investigated by using FTIR spectroscopy, UV-Vis, XRD, SEM and TGA. Electrical conductivity and viscosity of synthesized polyanilines were studied by four probe technique and Ubbelohde viscometer, respectively. XRD patterns and SEM images showed that acidic ILs are affected in crystallinity and formation of one and many dimensional nanostructures. Electrical conductivity, solubility, viscosity and thermal stability of synthesized polyanilines in acidic ILs medium are more than that the synthesized polyaniline in standard condition. It seems, ILs as a soft template caused growth and order of polyaniline chains in various morphologies.

Hypothesis: Currently, the dyes/heavy metal ions contamination of wastewater is the most important environmental problem throughout the world. Up to now, many techniques such as ion exchange, precipitation, adsorption, and membrane processes have been employed to remove dyes/heavy metal ions from water. Among them, adsorption is a simple and inexpensive technique for the removal of dye contaminations. The aim of the current work is the development of a low cost material based on hydrolyzed poly(N-vinylpyrrolidone-co- maleic anhydride) and rice husk as an effective adsorbent for Rhodamine B (RB) removal. The adsorption studies on the synthesized nanocomposite were carried out under different conditions, including, pH of solution, contact time, nanocomposite dosages and initial dye concentrations. Furthermore, the kinetic and thermodynamic studies of the adsorption data were examined.
Hydrolyzed poly(N-vinylpyrrolidone-co-maleic anhydride)/rice husk nanocomposite was prepared by a two-step method. In the first step, the poly (N- vinylpyrrolidone-co-maleic anhydride)/rice husk nanocomposite was synthesized through in-situ radical polymerization technique using benzoyl peroxide as initiator. In the second step, the hydrolyzed poly(N-vinylpyrrolidone-co-maleic anhydride) /rice husk nanocomposite was prepared through hydrolysis using sodium hydroxide solution (2 N).
Findings: The prepared nanocomposite was characterized by FTIR, XRD, SEM and TGA. The SEM images showed that the nanocomposite had a particle size between 50-100 nm and the XRD patterns revealed an amorphous structure. The results demonstrated that more than 88% of RB was removed by a nanocomposite synthesized under the conditions of pH 8, 70 mg adsorbent, 40 mg/L dye concentration and 180 min contact time. Furthermore, the experimental data showed a good agreement with Freundlich isotherm and pseudo-second order kinetic models.

Dextrin-g-polypyrrole/graphene oxides (PDGP/GO) nanocomposite was synthesized using in-situ polymerization and direct blending of PDGP and graphene oxide nanoparticles. The products were named nanocomposite 1 and nanocomposite 2, respectively. The prepared nanocomposites were characterized by Fourier transform infrared (FTIR) spectroscopy. Surface morphology and structure of nanocomposites were investigated by X-ray diffractometry (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The performance of the synthesized nanocomposites in removing Pb (II) and methylene blue dye from aqueous solutions was evaluated. The effect of pH, adsorbent dosage, contact time and contaminant concentration on Pb (II) and methylene blue uptake capacity was studied. On the other hand, the percentage removal of Pb (II) metal ion by nanocomposite 2 (96%) was higher than that of nanocomposite 1 (88%). The optimum condition for effective removal of methylene blue dye by nanocomposite 1 (94%) and nanocomposite 2 (98%) could be obtained at pH 8, nanocomposite dosage of 100 mg, contact time of 60 min and methylene blue concentration of 80 mg/L. Langmuir and Freundlich isotherm models, pseudo-first-order and pseudo-second-order kinetics equations and thermodynamic models were used to determine the mechanism of Pb (II) and methylene blue adsorption on the nanocomposite 2. The results showed that the Langmuir isotherm, pseudo-first-order kinetic and spontaneous adsorption were suitable models for Pb (II) sorption on nanocomposite 2, while the Freundlich isotherm, pseudo-second-order kinetic and spontaneous adsorption were suitable models for methylene blue dye removal. Therefore, the PDGP/GO nanocomposite prepared by direct blending could be considered as a promising adsorbent for Pb (II) and methylene blue removal from aqueous solutions.

Cross-linked poly(vinyl alcohol)/poly(vinyl pyrrolidone) (PVP/PVA) hydrogels were prepared in aqueous media using K2S2O8. The gel fraction, degree of swelling in water, and mechanical properties, such as TGA, DSC, and tensile strength were measured. It was found that the gel fraction increases with increasing potassium peroxodisulphate concentration but never reach to 100%. The swelling behaviour of the gels were specified by a relatively fast rate of swelling at the beginning of the process and measured as gram of water per minute. The amount of absorbed water as immersion water uptake of greater than 1400% is obtained. Because of the neutrality of the hydrogels, the maximum of swelling was achieved at pH=7. Maximum extents of swelling were achieved at 25oC and the swelling of hydrogels was found to decrease at higher temperatures. The hydrogel could be considered as a good barrier against common microbes including Sarcina lutea, Escherichia Coli, and Pesudomonase aeruginosa. The thermal analysis shows that the gels are stable up to 350oC. According to the DMTA thermogram, the glass temperature of 44.8°C is observed for 50 % w/w of hydrogel sample. Tensile strength as high as 90.8-10.0 Kg/cm2 and elongation-at-break about 60% were achieved using 1.1×10-5 M concentration of KPS