Simulation of the adsorption—microfiltration process for boron removal from RO permeate

Based on experimental data, a simulation and optimisation of the adsorption–microfiltration (AMF) process for boron removal from reverse osmosis (RO) permeate was done. An impressively low flow rate of the dry boron adsorbent of about only 54.3 kg h−1 is needed in the adsorbent recirculation loop of a unit for treatment of 100m3 h−1 of RO permeate and boron concentration in the feed and raffinate 1.2 and 0.4 mg dm−3, respectively. The optimum concentrations of dry adsorbent in the suspension leaving submerged microfiltration module (MF1) and cross-flow microfilters are 110 and 200 kg m−3, respectively. A diafiltration of regenerated adsorbent suspension is an effective way of decreasing of adsorbent flow rate and consumption of chemicals in the desorption loop. Use of about 0.5% of the raffinate for diafiltration is optimal. Specific consumption of regeneration media per unit volume of raffinate at these conditions are 0.97 and 0.19 mol m−3 for acid and alkali, respectively. Segmentation of submerged MF1 module is a useful way of reducing membrane area needed, which is at an optimal conditions in case of ideal mixing in segmented and non-segmented MF1 modules 1315 and 1695 m2, respectively. The overall theoretical power input for MF pumps and air blower is of about 0.018 kWh m−3.