چكيده به لاتين
Highly porous polymer absorbents (PolyHIPE) were made by emulsion polymerization method with a high percentage of internal phase, consisting of styrene and divinylbenzene monomers. Then 1-vinyl-imidazole monomer was added to the system. In order to stabilize the system during the synthesis, this monomer was inserted into the sponge structure with the help of a vacuum pump. 4 solutions with different monomer concentrations were used. FTIR analysis was performed to ensure the placement of this monomer in the sponge structure, and the wavelengths related to the functional groups containing nitrogen element were observed in the samples containing 1-vinylimidazole. The FESEM analysis of these 4 samples contained evidence of the placement of particles on the surface of the sponge walls. In order to check the efficiency of PolyHIPE sponge in the absorption operation and check the time to reach the equilibrium of the system, a certain amount of adsorbent equivalent to 0.3 gr/100ml was placed in a 1500 ppm solution of iron ion for 3 hours. During different time intervals, samples were taken from each solution container and subjected to ICP test. The system had reached equilibrium after 180 minutes and the highest removal percentage was related to the adsorbent with the highest percentage of 1-vinylimidazole monomer. In order to remove iron ions, iron oxide nanoparticles were needed, which after preparation were subjected to DLS analysis to measure the size distribution of the particles. Next, 3 solutions with different concentrations of iron oxide nanoparticles were introduced into the PolyHIPE sponge. By examining the adsorption efficiency of these 3 samples in the conditions mentioned in the previous case, it was found that the sample containing 15% 1-vinylimidazole and 20% iron oxide nanoparticles had the best efficiency of iron ion removal.Then, to investigate the effect of factors such as pH, effluent concentration and adsorbent dose, Design Expert software was used to design a statistical experiment with the response surface method. As a result, it was observed that increasing the effluent concentration from 1000 ppm to 2000 ppm causes a significant decrease in the removal percentage. Regarding the pH factor, the highest removal percentage was for pH=8. But the process of changes in removal efficiency relative to adsorbent dose depended on the effluent concentration. Next, the result of the effect of interfering ions on the absorption process indicated that the PolyHIPE sponge shows a favorable efficiency for the removal of different ions. Further, in order to check the mechanical properties of PolyHIPE sponge, modified cellulose nanoparticles were added to it. It was observed that the general trend of changes in Young's modulus is increasing with the increase in the percentage of nanoparticles. Different isotherms were examined for this research, and according to the correlation coefficient, the best describing isotherm in this research was the Langmuir isotherm. Also, pseudo-second-order kinetic model was found to be the optimal model for all 4 different percentages of 1-vinylimidazole monomer.
