Removal of Cobalt Ions from Wastewater by Batch and Flowing Forward Osmosis Processes

Abstract

This study was focused on forward osmosis batch and forward osmosis flowing processes to remove heavy metal (Co+2 ions) from wastewater. Cellulose triacetate (CTA) membrane was used as flat sheet for forward osmosis process. Potassium chloride KCl with different concentrations was used as draw solutions. The experimental work was divided into two parts. Forward osmosis flowing process as first part, was discussed under different operating parameters studied, such as the concentration of draw solutions (10-20 g/l), concentration of feed solutions (15-150 mg/l), temperature of feed and draw solutions (20-50)ºC, pH of feed solution (2-10), feed and draw flow rate were maintained at 50 l/h, and pressure was maintained at 0.25 bar gauge. Forward osmosis batch process as second part, was discussed under different operating parameters such as the concentration of draw solutions (10-120 g/l), concentration of feed solutions (15-150 mg/l), temperature of feed and draw solutions (20-50)ºC, and pH of feed solution (2-10). The results showed that the water flux increased along with the draw solution concentration, and temperature of feed and draw solutions and decreased with the increasing operating time of experiment, concentration and pH of feed solution. The value of rejection efficiency after 4hrs reached 81.19% for the FO flowing process and 73.19 % for the FO batch process.