Phosphorus removal and recovery from wastewater via hybrid ion exchange nanotechnology: a study on sustainable regeneration chemistries

Abstract

Abstract Technologies that allow for removal and subsequent recovery and reuse of phosphorus from polluted streams are imperative. One such technology is hybrid ion exchange nanotechnology (HIX-Nano), which may allow to produce a valuable nutrient solution following phosphorus desorption of the saturated media. This study evaluated the potential of four regeneration chemistries to desorb phosphorus from a commercially available HIX-Nano resin hybridized with iron oxide nanoparticles using a design of experiments (DoE) approach. More sustainable and less harmful regeneration solutions using a KOH/K2SO4 blend or a recovered NH4OH alkaline solution, along with tap water instead of synthetic acid, were compared to a control solution of KOH and H2SO4. Among the four regeneration methods studied, using the combination of recovered NH4OH and tap water shows the highest phosphorus recovery potential because: (i) it involves low cost and sustainable products, (ii) it showed a relatively high recovery efficiency (75 ± 15% as compared to the control at 89 ± 13%), and (iii) it did not demonstrate any significant dampening of the resin longevity after five adsorption and desorption cycles. Based on the DoE data, a series of regression models was developed to generate understanding of the effect of important operational parameters (volume of the regenerant solution, rinse speed, strength of the alkaline solution) on the phosphorus concentration in the recovered nutrient solution. Overall, this study indicates that HIX-Nano may contribute to providing a cost-effective and sustainable technological solution to tackle the phosphorus problem in wastewater treatment applications across the globe.