QUALITY IMPROVEMENT OF WATER RESOURCES BY REMOVAL OF MERCURY AND LEAD CONTAMINANTS THROUGH FORWARD OSMOSIS (FO) TECHNOLOGY WITH VIBRATING MEMBRANE

Nowadays, the forward osmosis (FO) has attracted a considerable attention due to its numerous abilities in the field of seawater desalination and wastewater treatment, fluid food processing and power production. This study is seeking to evaluate the effects of various parameters before and after the membrane vibration on the function of forward osmosis in mercury and lead desalination from water. In this study, a laboratory pilot is prepared for these assessments, and thus the parameters, which affect the removal of contaminants and membrane vibration, are evaluated. According to the results of this study, the percentage of removed mercury and lead metals is significantly increased, but the concentration of these elements is decreased in output solution in the lack of membrane vibration by increasing the temperature. The more the feed solution concentration has increasing trend, the more it shows the decreasing trend in percentage of mercury and lead removal from the feed solution. The effective osmotic pressure has a direct impact on the percentage of removed mercury and lead; and the percentage of removal will be increased by enhancing the effective osmotic pressure. The membrane vibration for 6000, 10000 and 14000 rpm of membrane vibrating motor has a different impact on the removal of heavy metal at the first and third stages respectively. The initial vibration always increases the percentage of removal compared to the steady state. This process will be much faster in the second vibration, and thus the percentage of removal will reach the highest level. The third vibration shows a significant decrease on the percentage of removal which is different depending on the rate of effective osmotic pressure. If the effective osmotic pressure is high (about 18 atm), the percentage of removal will be significantly dropped and will become less than before the vibration. If the effective osmotic pressure is measured within the average interval (about 8 atm), the percentage of removal will become about more than the initial vibration or lack of vibration, and if the osmotic pressure has the lowest value (about 4 atm), the third vibration has the percentage of removal between the first and second vibration. According to the results, this rate will always be lower than the second vibration. The results of this research indicate the opportunity for adding the membrane vibration to a solution for fouling elimination and increased percentage of as a novel method. According to the observed cases about the osmotic pressure and percentage of removal in the third vibration, the effective osmotic pressure can be considered as a parameter which affects the selection of draw solution.