Forward and Reverse Osmosis Process for Recovery and Re-use of Water from Polluted Water by Phenol

Faiq Al-Alawy, Ahmed

	Forward and Reverse Osmosis Process for Recovery and Re-use of Water from Polluted Water by Phenol
Journal of Engineering
Article 1, Volume 17, Issue 4, 2011, Pages 912-928
Author
Ahmed Faiq Al-Alawy
Abstract
The research aims to apply the novel forward osmosis (FO) process to recover pure water from contaminated water. Phenol was used as organic substance in the feed solution, while sodium chloride salt was used as draw solution. Membranes used in the FO process is the cellulose triacetate (CTA) and polyamide (thin film composite (TFC)) membrane. Reverse osmosis process was used to treatment the draw solution, the exterior from the forward osmosis process. In the FO process the active layer of the membrane faces the feed solution and the porous support layer faces the draw solution and this will show the effect of dilutive internal concentration polarization and concentrative external concentration polarization. In the FO process was a run-time for five hours, and the concentration of phenol 100 and 1000 mg/l, and for the NaCl the concentration was 10000 and 30000 mg/l. It was found that recovery percent increases with increasing time, while water flux through membrane decreases with increasing time. Also, it was found that recovery and water flux increases with increasing draw solution concentration, on the contrary, water flux and the percentage of recovery decreases with increasing the concentration of phenol (feed solution). Increase in draw solute (NaCl) concentration has more effect on the water flux in FO process compared with increase in the concentration of phenol. Outlet phenol concentration increases with time, while the outlet salt concentration decreases with increasing the time. The results showed that the cellulose triacetate membrane gave the highest recovery ratio from the thin film composite membrane. The highest recovery was reached in five hours is 51.33%, while using CTA membrane recovery rate increase, by 23% compared with TFC membrane. The value of the resistance to solute diffusion within the membrane porous support layer is 36.83 h/m. Reverse osmosis is perfect method for removal of dissolved salts from water, thus its suitable process for reducing the content of NaCl in draw solution; therefore the sodium chloride rejection percentage was 91.6 – 96 % for polyamide membrane (TFC). Within two hours of work of the reverse osmosis system the recovery percentage of pure water is 58%.
Keywords
Forward Osmosis; Reverse Osmosis; Recovery of Water; wastewater; Phenol; Membranes

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