Investigation of the Effect of Copolymer Antiscalant on TDS Removal Efficiency in Reverse Osmosis Membrane

Background & objectives: Nowadays, according to membrane-based filtration processes; the use of substances such as antiscalants that prevents the formation of deposits during the treatment process, is very important from industrial point of view. This study aimed to synthesize styrene-maleic anhydride copolymer (PSMA) using the radical polymerization method and to investigate the factors and parameters affecting its use in reverse osmosis membrane for removal of TDS from the Persian Gulf water sample. Methods: The present study was performed in laboratory scale to investigate the efficiency of synthetic antiscalants, in batch and fundamental-applied forms, as well as on a semi-industrial scale using reverse osmosis (RO) membrane system. Then, to evaluate its performance on the electrical conductivity (EC), total dissolved solids (TDS), flow flux, and membrane fouling in the reverse osmosis system, the effect of parameters such as pH and antiscalant concentration on increasing membrane efficiency and effectiveness were investigated. Results: The results showed that by adding antiscalant to the reverse osmosis system, the EC and TDS of the sample can be reduced in the range of 99.5-8.98% and 97.98-2.7%, respectively, so that in the study period, which was 1 hour, less performance reduction was observed in reverse osmosis membranes than in the absence of antiscalant. Also, the concentration of synthetic antiscalant up to 5 mg/L increased the efficiency, but had a small effect in higher amounts. Increasing the pH also had an adverse effect on efficiency of the reverse osmosis system and by increasing the pH from 7 to 9, the system efficiency decreased and higher TDS scores of 265.5 mg/L and 382.5 mg/L were observed in the treated effluent output, respectively. According to ANOVA statistical analysis and Prob> F values of 0.0004, the data were confirmed to be consistent. Also, a good match between the actual results and the predicted results of the software was confirmed and a logical relationship was obtained between the predicted and experimental regression coefficients. Conclusion: According to the results and by determining the optimal values of the studied parameters with a concentration of 5 mg/L antiscalants and at a pH of 7, the use of synthetic antiscalant increased the treatment efficiency using a reverse osmosis system. This material, by increasing the life of the membrane and preventing the formation of deposits on the reverse osmosis membrane, increased the time of use of this system and higher treatment efficiency was achieved in the reverse osmosis system in the presence of this anti-fouling.