فهرست مطالب m. torab mostaedi

Due to environmental, health, and economic concerns, recycling of plastic waste has increased significantly in recent years, and numerous mixes and composites of recycled polymer materials have been studied. Unfortunately, polypropylene makes up a very small portion of the five primary polymers that make up polymer waste. The aim of this study is to research the usage of recycled polypropylene (rPP) in combination with virgin polypropylene (PP) and to use electron radiation to improve the mixture's characteristics for potential applications. After being exposed to electron radiation, mixtures containing rPP at 0, 5, 10, and 15 wt.% were examined to ascertain their gel content, melt flow index, mechanical properties, and structural characteristics. The irradiation results in the formation of crosslinking in the PP mixture, as evidenced by the decrease in melt flow index and the result of gel content of the irradiated mixes. The tensile strength and elongation at break are unaffected by increasing the amount of rPP, but after exposure to radiation, the tensile strength of samples containing 0 to 10 wt.% of rPP declines by 10% and that of samples with 15% by weight reduces by 15%. In comparison to samples not exposed to radiation, the elongation-at-break increase was also reduced, which appears to be a result of developing a crosslinking net in the polymer's structure. The polymer mixture still exhibits a reasonable hammering behavior, and the decrease caused by the application of rPP and irradiation is of an appropriate quantity. The irradiation sample's analysis using a scanning electron microscope also demonstrates improved interaction of PP with rPP. Based on the findings, it would appear that the irradiation combination containing 10 wt.% rPP is the optimal sample to use for environmentally recycling post-consumer PP waste, creating new, high-performing products for a variety of applications, Cost reduction, and sustainable production.

The decontamination of structures with radioactive substances is one of the most important areas of environmental chemistry. In this study, an intelligent polymeric coating containing a Br-PADAP detector was made to identify and remove the uranyl nitrate contaminant (UO2(NO3)2.6H2O). In this study, the effect of pH was investigated for the first time. Also, the parameters of different substrates, detector concentration, contaminant drying temperature, coating drying temperature, and mechanical properties of the contaminant adsorption were investigated. The results of an evaluation of FT-IR, TGA, and liquid scintillation tests well prove the presence of uranium ions in the coating. The polymer coating containing the EDTA and Br-PADAP detector becomes purple to brown by absorbing a contaminant solution containing uranium ions. Quantitative evaluation based on MATLAB software image processing methods also shows a color change. Decontamination factors (DFs) in this coating were shown to be above 97% at 2000 ppm, and higher than in previous studies. The polymer solution was obtained with optimal formulation and flexible film.

Alkali decomposition with NaOH is the most commonly used method for extraction of zirconium from zircon mineral. This process includes alkali fusion, water leaching and acid leaching steps. In this study, Taguchi method was utilized to find the optimum operational conditions of alkali decomposition process. The results showed that under the optimal conditions of NaOH/ZrSiO4 mole ratio of 6:1, NaOH concentration of 30% and fusion temperature of 650 °C, 98.6% of the initial zircon was decomposed, as no pick of ZrSiO4 was observed in the XRD pattern of the alkali fusion product. The conditions of water leaching step were investigated as well, and under the optimal conditions of, liquid–solid ratio of 5:1, leaching temperature of 30 °C and leaching three times, 96.2% of sodium and 77.9% of silica content in the alkali fusion product were removed. The crystal phase structures of ZrO2 and SiO2 were observed in the residual solid after heat treatment. In the acid leaching step, leaching with 4 mol/L sulfuric acid with liquid/solid ratio of 20 at temperature of 60 °C, resulted in 92.73% recovery of zirconium and the silica content in the acid leaching solution was obtained 31 ppm. Results of this research suggest the optimal operational conditions of the facile, low price and proper industrial method for recovery of zirconium from zircon mineral.

In the present study, the uranium recovery by utilizing the bulk liquid membrane which contains Alamine 336 has been investigated. The effect of uranium and sulfuric acid concentration in the donor phase, carrier concentration in the liquid membrane phase, and ammonium carbonate concentration in the acceptor phase and transport kinetics were studied. The optimum conditions of uranium transport were obtained at 0.15 mol.L-1 H2SO4 in donor phase, 0.5 mol.L-1 (NH4)2CO3 in the acceptor phase, 0.0125 mol.L-1 Alamine 336 in kerosene. The results demonstrated that by increasing the concentration of sulfuric acid up to 0.15 mol.L-1  and the Alamine 336 concentration to 0.0125 mol.L-1, the uranium transfer will increase and then decrease. The uranium transfer was decreased with an increment in initial uranium concentration. Studying the effect of time on the uranium transfer showed that the cause of rate-controlling is the release of uranyl from the liquid membrane phase to the acceptor phase. The kinetics of uranium transport was modeled assuming consecutive irreversible pseudo-first-order reactions. The extraction rate constant of 0.0061 min-1 and 0.0107 min-1 and the stripping rate constant of 5.56×10-4 and 12× 10-4 min-1 were obtained for liquid membrane containing Alamine 336 and sulfated Alamine 336, respectively.

Rare earth compounds widely used in industrial applications and new processes with green solvents are appropriate for recovering these elements. In this study, the ionic liquid application development was investigated to extract europium ions in single and binary systems. A green procedure for europium (III) extraction from aqueous chloride solution was investigated using phosphonium ionic liquid Cyphos IL 104. Comparative conditions were investigated for analyzing better results with the presence of organic extractant such as Cyanex272, D2EHPA in the batch experiments. The experiment design was carried out based on the central composite design principles to analyze the relationships between the responses and the significant parameters. The obtained data revealed that the quadratic equation has good desirability to predict the extraction percentage. Investigation of the extraction process showed that the ionic liquid Cyphos IL104 has selective power in the extraction of europium and the efficiency is higher than the organophosphorus extractants. Accordingly, optimum conditions for maximum removal of europium ions were obtained equal to 5.5, 1, 16 min, and 0.008 M for feed acidity (pH), phase ratio, time, Cyphos IL 104 concentration. Examination of binary systems of rare earth elements showed that ionic liquid had positive and negative effects on the separation factor. The high efficiency of ionic liquid in the reuse condition indicated that the system is appropriate from an economic perspective.

Alkali fusion with NaOH is the most commonly used method for the extraction of zirconium from zircon sand. In the alkali fusion process, the acid leaching step has a great influence on the zirconium recovery and purity of the final product. In this study, the Grey-Taguchi method was utilized to find the optimum conditions of the acid leaching process. In order to apply this method, acid type, acid concentration, leaching temperature, and liquid/solid ratio were selected as control factors with responses of zirconium recovery and R=Si/Zr ratio. The results demonstrated that the optimum condition for acid leaching requires 4 mol/L sulfuric acid with a liquid/solid ratio of 20 at 60 °C. Zirconium recovery and Si/Zr ratio (R) under these optimum conditions were 92.73% and 0.0018, respectively. Also, the silica content in the acid leaching solution was 30.94 ppm. The results of this research suggest facile, low price, and proper method comparing to the carbochlorination method for recovery of zirconium from zircon mineral.

In this study, the thermal decomposition of thorium oxalate dihydrate (Th(C2O4)2. 2H2O) was investigated by using design of experiment- technique. The thermal decomposition experiments were carried out in a two- temperature procedure and the influence of the decomposition temperature of the second step, as well as, durations of both steps on the crystallinity, size, size distribution, morphology and specific surface area of the produced thorium oxide were investigated. For this purpose the experiments were designed by using Taguchi method. The results showed that the optimum decomposition temperature and duration of the first and second heating stages were 400 °C for 4 hours and 750 °C for 4 hours, respectively. The powder characterization showed that the cubic thorium oxideparticles synthesized in the optimal conditions had uniform size distribution with an approximate size of 350 nanometers. Moreover, the crystallinity of ThO2 phase and specific surface area of these particles were 95% and 35.23(m2 g-1), respectively.