Integrated solution for boron removal from seawater using RO process and sorption-membrane filtration hybrid method

The main objective of this work was to investigate the possibility of implementing a new hybrid system which combines reverse osmosis (RO) process with sorption-membrane filtration method. The RO tests were performed using a small-scale seawater reverse osmosis (SWRO) system which was established in Urla Bay, Izmir, Turkey. Dowex (XUS 43594.00) ion exchange resin with a particle size of 0–20 μm was employed for removal of boron from RO permeates. A submerged-style hollow-fiber module containing two polypropylene membranes (diameter: 1.3 mm, thickness: 200 μm, pore diameter: 0.4 μm) and a ZW-1 model submerged ultrafiltration module was used throughout the sorption-membrane filtration hybrid system. Sorption of boron was performed on a fine powdered boron selective ion exchange resin and boron loaded resin was separated by submerged membranes later on. The main advantage of sorption-membrane filtration hybrid process is the opportunity of using very fine particles of the resin, which increases specific surface and results in faster kinetics. Process variables such as resin concentration in the suspension, flow rates of fresh and saturated resins, and permeate have been evaluated in order to determine the efficiency of the hybrid process for boron removal from RO permeate.