فهرست مطالب somaye mashhadi

This study aims is to assess the tetraethylenepentamine-functionalized Rosa Canina-L fruits activated carbon prepared by microwave-assisted technique for the removal of Methylene Blue dye from an aqueous solution. The morphological and anatomical characterization of the developed adsorbent was carried out using various analytical techniques such as Fourier Transform Infrared Spectroscopy and Field emission scanning electron microscopy. The surface morphology and physical condition of the absorbent surface show a porous morphology that contains numerous deep holes suitable for dye absorption. Taguchi design of the experiment was used to find the best conditions for the removal of MB dye from the aqueous solution. The effects of different parameters such as pH, adsorbent dose, reaction time, initial dye concentration, and temperature at 3 different levels were considered using an L27 Taguchi method. Analysis of data was performed using one- way variance and calculation of signal-to-noise rate. Based on signal- to- noise ratios, the optimum process conditions were pH 4, adsorbent dose 0.03 g, contact time 30 min, initial MB concentration 25 mg/L and temperature 298 K. According to one- way variance results, the influence of the controllable factors in descending order is pH > adsorbent dose > temperature > initial dye concentration > contact time. Moreover, the adsorption behavior of this adsorbent fits well with the Langmuir isotherm and pseudo-second-order kinetic model. The whole process of adsorption of Methylene Blue dye onto this adsorbent was found to be spontaneous and exothermic under standard conditions.

In this study, we have synthesized a new Fe3O4/AC nanocomposite using low cost adsorbent by microwave assisted in situ co-precipitation technique that was used as an effective adsorbent for the removal of methylene blue (MB) using the Taguchi design method as an optimization strategy. The optimum parameters are pH 7, Fe3O4/AC nanocomposite dose 0.03 g, contact time 30 min, initial concentration of MB 25 mg/L and temperature 298 K. The obtained results of ANOVA show that their percent contribution in descending order is pH (66.81%) > adsorbent dose (25.54%) > temperature (4.83%) > initial MB concentration (1.23%) > contact time (0.32%). The kinetic data were fitted to the pseudo-first-order, pseudo-second-order and intra-particle diffusion models and adsorption of MB dye followed pseudo-second-order kinetic. The obtained values of regression coefficient for Langmuir (0.98), Frendluich (0.93) and Dubinin–Radushkevich (0.94) showed that adsorption process fits to the Langmuir isotherm and the maximum adsorption capacity is 384.6 mg/g. Moreover, the thermodynamics studies suggested the spontaneous nature of adsorption process.

In this work, the Nanofibers were synthesized using electrospun of polystyrene solution in DMF/ THF solvent. The important parameters such as voltage, the distance between injector and collector, speed injection, the concentration of polystyrene and speed rotation of collectors in electrospun technique were optimized. Results showed that, within certain limits, by increasing the voltage, high Electro distance, low injection rate and high speed of the collector, we will get the Nanofibers with diameters less and regular chain structure. In optimal conditions, the average of polystyrene fibers diameter was 70-102 nm. Polystyrene absorbent modified by dithizone. By selecting the best conditions, the modified polystyrene Nanofibers were produced with an average diameter of 73-126 nm. The synthesized polystyrene Nanofibers were used for preconcentration of Copper in wastewater samples. The effective parameter on extraction such as adsorbent amount, pH, type and volume of eluent solvent and salt amount was evaluated and optimized with “one at the time” method. According to the results, optimum conditions are the solid phase: 0/006 gr, pH = 7, eluent solvent: acetonitrile solution with a volume of 0/7 mL, 1/3 g amount of potassium nitrate salt. This method was applied to real samples and good results were obtained. High enrichment factors and very good detection limit are highlights of this method.