Showing 3 results for Alamdar Milani
Volume 1, Issue 2 (Spring 2023)
Abstract
In the Magnetically Assisted Chemical Separation (MACS) process, tiny ferromagnetic particles coated with solvent extractant are used to selectively separate radionuclides and hazardous metals from aqueous waste streams. The contaminant-loaded particles are then recovered from the waste solutions using a magnetic field. In the present study, Cyanex272 or C272 (bis (2,4,4-trimethylpentyl) phosphinic acid) coated magnetic particles are being evaluated for the possible application in the extraction of Uranium (VI) from nuclear waste streams. The uptake behaviour of U(VI) from nitric acid solutions was investigated by batch studies.
Adsorption of uranium (VI) from aqueous solution onto adsorbent was investigated in a batch system. Adsorption isotherm and adsorption kinetic studies of uranium (VI) onto nanoparticles coated Cyanex272 were carried out in a batch system. The factors influencing uranium (VI) adsorption were investigated and described in detail, as a function of the parameters such as initial pH value, contact time, adsorbent mass, and initial uranium (VI) concentration. Magnetically Assisted Chemical Separation (MACS) process adsorbent showed best results for the fast adsorption of U (VI) from aqueous solution at aqueous phase acidity value of 0.5 molar. In addition, more than 80% of U (VI) was removed within the first 2 hours, and the time required to achieve the adsorption equilibrium was only 140 minutes. Langmuir and Frendlich adsorption models were used for the mathematical description of the adsorption equilibrium. Equilibrium data agreed very well with the Langmuir model, with a maximum adsorption capacity of 48 mg.g-1. Adsorption kinetics data were tested using pseudo-first-order, pseudo-second-order and intra-particle diffusion models. Kinetic studies showed that the adsorption followed a pseudo-second-order kinetic model, indicating that the chemical adsorption was the rate-limiting step.
Volume 5, Issue 1 (7-2021)
Abstract
Abstract:
Research subject: Leaching and recovery parameters controlling the releasing of selenium from Sar-Cheshmeh copper anode slimes are studied and determined.
Research approach: Copper anode slimes is produced during the production of cathodic copper at the bottom of electrolyte cells, which is composed of insoluble anode components in the electrolyte. The copper anode slimes are made up of those components of the anodes, which are not soluble in the electrolyte. They contain varying quantities of precious metals like gold, silver, selenium and tellurium, and other precious metals in the anodic copper. They are being extracted as a by-product in the copper production process. Due to the fact that the main source of selenium is sulfur deposits such as copper and nickel. Copper anodic slimes is currently the only source of selenium in the world. In this study, the extraction of selenium from anodic copper slimes has been feasible. To do this, acid leaching has been used. Copper anodic sludge is the raw material for the production of more than 90% of the world's selenium and is the main source of selenium production.[1-3]
Main result: In this paper, the effect of operational parameters such as acid concentration, temperature, process time and liquid to solid ratio on selenium recovery through copper slimes leaching was investigated. The optimum conditions of batch leaching For maximum selenium extraction from anodic copper slimes are attained at 3 mol L-1 of HNO3 concentration, 0.01 (W/V) solid to liquid ratio for 60 min contact time at 70 ºC. Under the optimized conditions, the selenium leaching efficiency was 99%. The thermodynamic data showed positive values of both ΔH and ΔS which indicates that the leaching process is indeed endothermic and random while the obtained negative values of ΔG show that selenium dissolution process is spontaneous in nature.
Volume 5, Issue 1 (7-2021)
Abstract
Research subject: With the rapid development of science and technology, cerium and cerium oxide are widely used in various fields, including in the manufacture of aluminum, aluminum alloys, some steels and in permanent magnets, catalysts, Polishing powder, Glass, Cinema, and Ceramic Technology. Solvent extraction is one of the effective techniques for extraction, separation, and purification of cerium.
Research approach: The extraction of cerium(IV) from sulfuric acid solutions using Cyanex 921 in kerosene was investigated. The different parameters affecting the extraction process of cerium(IV) such as pH of aqueous solutions, reagent, metal ion concentration, contact time as well as temperature, are separately investigated. Experiments in the pH range of 0.5 to 5.5, at 25±1 oC, using Cyanx 921 in the concentration range of 0.06 to 0.4 mol L-1, and a mixture of Cyanx 921 and D2EHPA was performed in different ratios.
Main results: From the temperature study, the extraction reaction for Ce(IV) was found to be exothermic in nature. The results indicated that the effective extraction of cerium(IV) from sulfuric acid solutions cannot be achieved in a single equilibration because the solubility of Cyanex 921 in aliphatic diluents is limited at ambient temperature. To rectify this issue, the possibility of using a synergistic mixture of Cyanex 921 and D2EHPA as extractant system to recover cerium(IV) from sulfuric acid solutions was investigated. Mixtures of Cyanex 921 and D2EHPA resulted in synergistic extraction of cerium(IV) from sulfuric acid solutions. The results indicated that, under experimental conditions, the maximum synergistic coefficient was obtained at the molar ratio of (0.6M D2EHPA/0.2M Cyanex 921) 3.0, and cerium(IV) was extracted into organic phase in the form of Ce(SO4)(HSO4)2.Cyanex 921.
