Polyepoxysuccinate as a green scale inhibitor for Ba2+ to mitigate irreversible blockage of reverse osmosis membrane during treating landfill leachate

Barium ion (Ba 2+ ) in landfill leachate is easy to combine with SO 4 2− introduced in acidification treatment stage to generate BaSO 4 precipitate, which causes irreversible blockage of reverse osmosis (RO) membrane in the post-treatment stage. To maintain the stable operation of RO membrane system treating landfill leachate, this study systematically investigated polyepoxysuccinate (PESA) as a green scale inhibitor for Ba 2+ to mitigate irreversible blockage of RO membrane. The feasibility experiments showed that PESA (0.60 mg/L) could make the scale inhibition rate (SIR) close to 100 % for Ba 2+ (10.00 mg/L). Adding PESA before the acidification treatment of landfill leachate remarkably improved the scale inhibition effect for Ba 2+ . The coexisting Ca 2+ and Mg 2+ made PESA dosage slightly increase to achieve high SIR for Ba 2+ , but the common scale inhibitor 1-hydroxyethylidene-sodium bisphosphonate (HEDP) for Ca 2+ and Mg 2+ showed little interference. The application experiments showed that the PESA dosage of 1.00 mg/L achieved an SIR of close to 70 % for the real landfill leachate with Ba 2+ of 5.09 mg/L. Furthermore, PESA was proved to effectively mitigate the irreversible blockage of RO membrane treating real landfill leachate via inhibiting Ba 2+ scaling. The analyses of X-ray diffraction, elemental composition and Fourier transform infrared spectroscopy showed that the scale inhibition mechanism of PESA for Ba 2+ includes mainly chelating solubilization and lattice distortion . Accordingly, PESA showed a good prospect in scale inhibition for Ba 2+ to mitigate irreversible blockage of RO membrane during treating landfill leachate. • PESA as a green scale inhibitor for Ba 2+ in landfill leachate was validated. • Adding PESA before acidification showed better scale inhibition effect. • Coexisting Ca 2+ /Mg 2+ with Ba 2+ slightly increased PESA dosage to keep similar SIRs. • PESA mitigated irreversible blockage of RO membrane treating real landfill leachate. • Major scale inhibition mechanism includes chelating solubilization and lattice distortion.