فهرست مطالب rahman salamat-ahangari

Raisin factories face a problem called waste and unusable waste in their industry. Due to the richness of industrial waste in this industry from carbon, in this work, we synthesized activated carbon by chemical method from raisin waste. For the synthesis of activated carbon, a chemical method with a zinc chloride activating agent was used in one to one mass ratio. After the optimization of various parameters such as type of activation agent, the ratio of activating agent, carbonization temperature and carbonization time, the best conditions for activated carbon were obtained. Then, in order to evaluate the efficiency of the synthesized activated carbon, a methylene blue dye removal test as a model was performed. Optimal conditions for the removal of methylene blue dye using the activated carbon including neutral pH, ambient temperature and the amount of adsorbent 0.01 g in 10 mL of solution with a concentration of 20 mg L-1 were obtained. In these conditions, the removal efficiency is more than 99%. The adsorption capacity is about 20 mg g-1 and the reaction kinetics is quasi-second order and according to thermodynamic studies the endothermic reaction is spontaneous and with increasing entropy. The dye adsorption mechanism on the adsorbent also follows the Langmuir isotherm, which indicates the uniformity of the adsorbent surface and the monolayer adsorption. Finally, in order to compare the performance of synthetic activated carbon, the amount of dye removal under optimal conditions was compared with the commercial activated carbon including Merck, Jacobi and activated carbon obtained from the almond shell. The results showed that synthetic activated carbon can compete with commercial samples.

This study has been undertaken to investigate into limiting molar conductivity, Walden product and subsequently association constants of some symmetrical uni-univalent alkali metal salts of lithium chloride, sodium chloride, potassium chloride, potassium bromide and potassium iodide in the mixed sucrose + water solvents ( 10 % and 20% weight percents) with concentration ranged covered from 0.004 up to 0.1 mol L-1 at 298.15 K. Data correlation and comparative studies was done using Fuoss-Justice , Debye-Huckel-Onsager (DHO), Bjerrum and Fuoss 1958 models. The results by DHO was not reasonable and led to negative values for association constants, Bjerrum model was not sensitive to distance parameter and led to the same result for potassium and the same for chloride salts, in the same manner but straightforwardly Fuoss 1958 led to the identical results for some cation and anion , whereas Fuoss- Justice model with remarkably dependency on distance model parameters agreed with experimental data excellently and the trend of association constants, limiting molar conductance and Walden product were concordant. Additionally the present study manifests the variability of Walden product and hydrodynamic radii for lithium and sodium iodide meaningfully.

Stabilizations and atomic level quadrupole coupling constant (CQ) properties have been investigated for graphene–like monolayers (G–monolayers) of boron nitride (BN), boron phosphide (BP), aluminum nitride (AlN), and aluminum phosphide (AlP) structures. To this aim, density functional theory (DFT) calculations have been performed to optimize the model structures and also to evaluate the CQ parameters. The results of optimizations indicated that the formations, polarities, and semiconducting properties of BN G–monolayer are more favorable than other investigated G–monolayers. Moreover, the atomic level CQ parameters also indicated that the atoms at the tips of monolayers have the most activities among other atoms and different properties have been seen for the atoms at different positions of monolayers. Differences of electronegativities are also important for the magnitudes of CQ properties as could be seen by larger values of CQ parameters for B and Al atoms in the BN and AlN G–monolayers in comparison with BP and AlP G–monolayers.