Enhancing the regeneration efficiency of a hybrid anion exchange resin for removal of phosphorus from wastewater with a lower environmental impact

Adsorption presents an interesting alternative to traditional phosphorus removal technologies because it excels at achieving low levels of phosphorus (P). One leading adsorption technology is called HAIX (Hybrid Anion Exchanger) and is made from ferric oxide nanoparticles impregnated in a strong base anion exchange resin. This adsorption media, marketed as FerrIX A33E, offers great performance in terms of P removal, but requires substantial quantities of sodium hydroxide (NaOH) and sodium chloride (NaCl) to regenerate. A new version of HAIX (named WBA-2) was previously synthesized using a weak base anionic resin. It showed better regeneration abilities under lower concentrations of NaOH and no NaCl. In this study, breakthrough curves of WBA-2 and FerrIX were compared over three adsorption/regeneration cycles with 0.1 M NaOH as the regenerant solution. FerrIX was able to treat 1630 bed volumes in the first cycle, but only managed to treat 800 bed volumes in the third cycle. WBA-2 was able to keep its full treatment capacity with 1470 bed volumes treated in the first cycle and 1500 for the third. To push the regeneration efficiency of WBA-2 even further, its regeneration was evaluated at 24 °C, 50 °C and 80 °C. Higher temperature during regeneration yielded higher performance with 79 %, 85 % and 91 % ± 1 % of regeneration efficiency for the three temperatures in increasing order. Finally, this study discusses the possibility of using onsite electrolysis to provide the consumables needed for the regeneration of HAIX, and demonstrates how using higher temperatures during electrolysis and regeneration of HAIX can improve overall operational performance. • Hybrid anion exchanger (HAIX) is an interesting technology for phosphorus removal. • WBA-2 is an HAIX adsorption media that requires less chemicals to regenerate. • At higher temperatures WBA-2 regeneration efficiency is improved. • Onsite electrolysis can be used to provide the chemicals for HAIX regeneration. • Higher temperatures can also decrease the voltage required to drive electrolysis.