جستجوی مقالات مرتبط با کلیدواژه « پلی (n- وینیل پیرولیدون-کو- مالئیک انیدرید) » در نشریات گروه « مهندسی شیمی، نفت و پلیمر »

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.

Poly (N- vinylpyrrolidone -co- maleic anhydride) @ eggshell @ Fe3O4 (PNVPMA@ES@Fe3O4) eco-friendly nanocomposite was synthesized by a two-step method. In the first step, the PNVPMA copolymer was synthesized via radical polymerization method. In the second step, the PNVPMA@ES@Fe3O4 nanocomposite was synthesized through an in-situ co-precipitation technique. The PNVPMA@ES@Fe3O4 nanocomposite was used as high performance eco-friendly adsorbent to remove Congo red (CR) dye from aqueous solutions at various conditions, such as pH effect, contact time, adsorbent dosage and dye concentration. Results showed that the percentage removal of CR by synthesized magnetic nanocomposite was more than 95% at pH=6 and contact time 30 min. The results showed that the interactions between CR and the PNVPMA@ES@Fe3O4 nanocomposite were in agreement with the Langmuir isotherm and pseudo second order kinetic model. Also, thermodynamic model showed that the CR adsorption on the synthesized nanocomposite was spontaneous.