The purpose of this study is to experimentally investigate the SAR (Sodium Adsorption Ratio) and TDS (Total Dissolved Solids) reduction in reverse osmosis (RO) concentrate, using two types of natural zeolites. In order to reduce salinity of wastewater, experiments are carried out by varying the type of zeolite, concentration of zeolite, and residence time. The results show that both zeolites can lower the SAR and TDS of wastewater; however, Rhyolitic tuff is more effective than clinoptilolite. It is observed that the concentration of zeolite has not significant effects on wastewater treatment so, using the lowest level of selected concentration reduces the cost of desalination. In addition, the effect of residence time is negligible. The experimental set up shows that the SAR reduction slop is higher than TDS.
Authors:Fatemeh Bahadori, Alireza Azizi and Kamran Ghasemzadeh
In the present study, ethylbenzene dehydrogenation to styrene monomer over a potassium-promoted iron oxide catalyst in radial fixed bed reactor was simulated. The pseudo-heterogeneous model was employed to predict ethylbenzene conversion and selectivity of styrene monomer, toluene, and benzene. The simulation results showed that deactivation of catalysts causes reduction in the reaction zone; therefore, the ethylbenzene conversion decreases. It is proposed that, for compensating the conversion reduction, the feed temperature is increased 1 °C per 5 cm of deactivated length. Simulation results are in good agreement with the experimental data obtained from real plant.