Spiral Wound Reverse Osmosis Membranes for the Recovery of Phenol Compounds-Experimental and Parameter Estimation Studies

Abstract

Problem statement: Reverse osmosis is increasingly used as a separation technique in chemical and environmental engineering for the removal of organics and organic pollutants present in waste water. The removal of an organic compound, namely phenol, using a polyamide membrane was investigated in this study. Waste water containing phenol present a serious environmental problem and increasing attention is being given for its removal using RO membranes. Objective of this study is to (i) generate experimental data related to the removal of phenol using a spiral wound polyamide membrane (ii) analyze the performance of the membrane using solution-diffusion model and validate the model with the experimental data. Approach: Experiments were conducted on a laboratory scale spiral wound polyamide RO module. The permeate concentrations and rejection coefficient values were measured for various feed inlet pressures and feed concentrations. The total feed flow rate, 3.33×10^-4 m³ sec^-1 (20 LPM) was not varied. The transport of solvent and solute through the membranes were analyzed using solution-diffusion model taking concentration polarization into account. Results: By varying inlet pressures from 4-14 kgf cm^-2) and feed concentrations of phenol from 200-1100 ppm, the rejection coefficients of the membrane were measured and found to vary from 64-91%. The solvent and solute transport parameters were determined by a graphical procedure using the experimental data and its values were 5.9×10^-7 (m atm^-1) and 6.54×10^-7 (m sec^-1) respectively. Conclusion: The model and the estimated parameter values were validated with the experimental data. The model was able to predict the rejection within 10% error. In view of the fact that not much information is available on the usage of spiral wound polyamide RO membrane modules for the removal of phenolic compounds, it may be concluded that the experimental results reported in this study is very significant in the scale up and design of RO system for treatment of industrial effluents containing phenolic compounds.