چكيده به لاتين
The purpose of this research is the synthesis of urchin nanostructures based on iron-manganese binary oxide and investigation of the factors affecting the morphology of nano-urchin-like and the physical and chemical properties of the nano adsorbent especially the specific surface area and funectional groups inorder to use separation processes of the pharmaceutical pollutant diclofenac sodium from aqua solution. At first, the effect of the effective factors in the synthesis stage with the co-precipitation method on needle morphology was studied by using Taguchi 9L test design. After checking the initial synthesized structures, the synthesis steps were repeated taking into account a more important factor called reaction time in order to obtain needle structures with better morphology and more surface area. Different characteristics of particles, including morphology, physical and chemical properties, were studied and investigated by means of scanning electron microscope tests, elemental analysis, X-ray diffraction, Fourier transform to infrared, determination of specific surface area, average size of pores and zeta potential. The results of the characteristic analyzes of the optimized sample showed that increasing the initial ratio of the reactants along with the reaction time at the optimal temperature had a significant effect on the specific surface area, the average size of the holes and the total volume of the holes, which is of importance due to the application of the synthesized needle nanostructure in the surface absorption process. It has a high capacity to increase the absorption capacity and reduce the pollutant concentration. In order to compare and understand more about the difference in needle nanostructure morphology with changes in the synthesis process, a smooth model structure based on iron-manganese binary oxide was synthesized. By comparing the characterization results, it was found that the synthesized structure in the smooth model in the wavelength range of 790-897 cm-1 lacks the spectrum indicating the FeO-OH bond (goethite). Also, the results of X-ray diffraction spectroscopy analysis and specific surface area in different models of synthesized needle nanostructures show that the value of specific surface area increases with the increase of the crystalline percentage of needles in a fixed ratio of raw materials. The results of the analysis of the specific surface area in two smooth and needle models show that the optimized needle nanostructure number 5 has a specific surface area of 198 m2/g with an average pore size of 5 nm, which is compared to the smooth model with a specific surface area of 18 m2/g and average The size of the pores is 15 nm, and the structure of the holes of both models is based on the Iopak classification of mesoholes. The above needle nanostructure with the amount of 0.03 grams in the concentration of 60 mg/liter of diclofenac, pH = 4.5, temperature of 25 degrees Celsius and time of 3 hours has the ability to remove diclofenac sodium in the process of surface absorption in the closed system by 83.3%. is much higher compared to the results using the smooth model absorber. The absorption balance experiments show that the absorption of diclofenac on the smooth needle nanostructure follows the Langmuir-Freundlich model and the maximum absorption capacity of diclofenac with the needle and smooth nanostructure in the Langmuir model at 25°C is 126.5 and 66.25 mg/g, respectively. The pH factor has played an important role in the performance of the surface adsorption process.. Considering the electric zero point of both adsorbents in the range of 7.7 to 7.8 and the PKa of diclofenac sodium (4.2), the adsorption mechanism at lower pH with electrostatic interaction between The functional group of diclofenac sodium COO- and the positive charge of the absorbent surface and in the needle nanostructure model the formation of a complex between the nanoneedles (iron oxide hydroxide) and the functional group in diclofenac sodium are explained.
