جستجوی مقالات مرتبط با کلیدواژه « Cationic » در نشریات گروه « مهندسی آب »

Over the past decades, the sharp increase in population growth and industrialization in developing countries has reduced the quality and quantity of water resources. Water Treatment and purification technologies are rapidly developing in membrane separation processes. In this study, the effect of anionic and cationic surfactants on the performance of polyamide membrane nanofiltration was investigated experimentally. Nanofiltration membranes were constructed by adding anionic surfactant Sodium Dodecyl Sulfate and Hexadecyltrimethyl ammonium bromide cationic with a filming machine. The highest percentage of salt excretion related to the polyamide nanofiltration membrane without adding surfactant with the amount of 16.19% at 180 minutes. Also, the greatest amount of water flowing from the polyamide nanofiltration membrane is related to the time of 30 minutes and the state where the anionic surfactant is added to the membrane by weight of 10%. In this case, the amount of water flowing through the membrane of polyamide nanofiltration was 37.76 L/m2. When anionic surfactant was added to the membrane at a rate of 10%, the membrane water flux was 41.48% higher than the pure membrane (no additive).

The presence of nitrate in groundwater resources has instigated increasing concerns among both managers and users of, especially, drinking and sanitation water. From among the different nitrate removal methods, the adsorption method has attracted more attention thanks to its high removal efficieny and economical operation. Commercial activated carbon ranging in mesh size from 30‒40 was utilized to remove nitrate from an aqueous solution. In order to enhance nitrate uptake, different acid, alkaline, and cationic surfactant post-treatments were examined. Alkaline post-treatment followed by cationic surfactant modification was found to yield the best efficiency. FTIR, SEM, and N2 adsorption/desorption were carried out to determine the physical and chemical properties of activated carbon. Kinetic tests revealed that adsortption reached its equilibrium state after 12 hiurs and that the pseudo-second order and Freundlich models. Based on the Langmuir model, maximum adsorption capacity was found to be 15.34 and pH had an insignificant effect on nitrate adsorption. Moreover, the highest decline in nitrate adsorption was observed in the presence of sulfate followed by chloride, phosphate, and carbonate. Based on the results obtained, the modified activated carbon accompanied by washing with sodiuym hydroxide and modified cationic surfactant post-treatment might be recommended for use in adsorption processes as a promising innovative technology for nitrate removal from drinking water.