MODIFIED THIN FILM COMPOSITE REVERSE OSMOSIS MEMBRANE AND A PROCESS FOR PREPARATION THEREOF

摘要

The present invention relates to a complete process for preparation of high flux and salt rejection thin film composite (TFC) reverse osmosis (RO) membrane including process for preparation of support membrane for thin film, process for thin film coating of support membrane by in-situ interfacial polymerization between diamines and trimesoyl chloride, machine design, chemistry and details of process (engineering+chemistry+ambient) parameter at 1×100 sqm scale upgradable to a scale even 10-20 times higher. The produced membrane is characterized by 96% salt rejection and 48 LM-2H 1 flux with 2000 ppm sodium chloride solution at 250 psi pressure and 95% salt rejection and 46 LM2H 1 flux with 35000 ppm sodium chloride solution at 900 psi pressure. The present invention also relates to complete machine design for PSF ultrafiltration membrane casting and coating for TFC membrane production at commercial level.

主权项

1. A modified thin film composite (TFC) reverse osmosis membrane on conventional polysulphone support wherein membrane comprises polyamide ultrathin layer which is formed by interfacial polymerization reaction by reacting aqueous solution of polyfunctional amine(s) in the range 2-3% (w/v) with polyfunctional acid chloride(s) in the range of 0.1-0.125% in hexane at aqueous-organic (hexane) interface to form polyamide thin film composite membrane, wherein the polysulphone support membrane with polyfunctional amine(s) on top surface travels in air before entering the polyfunctional acid chloride(s);
followed by post treatment of said nascent TFC membrane by first washing with citric acid followed by water and then treated with solution having methacrylate monomers in the mole ratio in the range of 4×10−3 mol/L to 4×10−2 mol/L (0.1-1% w/v), methylene-bis-acrylamide or ethyeleneglycol dimethacrylate, sulphopropyl methacrylate, ceric (iv) ammonium nitrate/sulphate salt and polyvinylalcohol or polyethyleneglycol in presence of nitric acid or sulphuric acid to enhance fouling resistance and chlorine stability compared to the conventional unmodified TFC membrane.