جستجوی مقالات مرتبط با کلیدواژه « روش سطح پاسخ » در نشریات گروه « فیزیک »

Heavy metal ions have increased wastewater production with the development of various nuclear activities. One of the most significant metal ions that harm the environment and living organisms, especially humans, is the uranyl ion. There are many methods to remove metal ions, and biological adsorption is the cheapest and most efficient method. In this research, the absorption of uranyl ions from aqueous solutions from tea waste has been studied. Due to the presence of various functional groups such as carboxyl, hydroxyl, amine, etc, tea wastes have good cations adsorption ability. The effective parameters in adsorption including pH, adsorbent dose, temperature, initial uranyl concentration, and contact time parameters were investigated. Response surface methodology (RSM) was used to conduct experiments and analyze the results. The optimum conditions for uranyl adsorption by tea waste adsorbent were pH = 3.9, temperature 25°C, adsorbent dose 0.275 g, initial concentration of uranyl 10 mg/L, and contact time 90 minutes. Using Freundlich's isothermal and pseudo-second-order models, we fitted the most accurate isothermal and kinetic models. Results showed that tea waste was a good bio adsorbent for uranyl adsorption from real wastewater with a 93.50% adsorption rate.

In this study, graphene oxide (GO) adsorbent was prepared by modified Hummer’s method and functionalized with aminomethylphosphonic acid. Its application to the adsorption of Sr ions from aqueous solutions in a batch sorption process was investigated. Adsorbents were characterized by TEM and FT-IR. The TEM images of functionalized graphene oxide showed that graphene sheets are formed in wavy sheets. The FTIR spectrum revealed that graphene oxide was highly functionalized with aminomethylphosphonic acid and oxygenated functional groups were reduced. Response surface methodology investigates pH, adsorbent dosage, and temperature parameters. The quadratic model corresponds well with the experimental data. The results illustrated that there is no systematic error in the experiments. The verification of the model with random experiments showed a low error in the values predicted by the model. The kinetic data were analyzed by Pseudo-first-order, Pseudo-second-order, and Double- exponential kinetic models, and experimental data were well modeled by the pseudo-second-order kinetic model. The research results showed that graphene oxide functionalized with aminomethylphosphonic acid has a good ability to strontium adsorption from aqueous solutions.

The ability of amino-functionalized hydrothermally synthesized titanosilicate nanoparticles (TiSiNH2) was investigated for the adsorption of Th(IV) from aqueous solutions in batch mode. The effects of four process independent variables including pH, initial metal concentration, sorbent amount and temperature were investigated using response surface methodology (RSM) based on central composite design (CCD). The accuracy of model was verified by coefficient of determination. The results of optimization showed that the sorption capacity of TiSiNH2 for Th(IV) under optimal conditions was 83.04 mg g-1. The results of modeling showed that, experimental data of adsorption capacity of sorbent for Th(IV) were better fitted with double exponential kinetic model and Langmuir isotherm can describe the equilibrium data well. The maximum adsorption capacity of TiSiNH2 for Th(IV) was estimated to be 87.71 mg g-1 by Langmuir isotherm.