Electrodialysis for Recovering Salts from a Urine Solution Containing Micropollutants

Abstract

Electrodialysis was investigated for the separation of micropollutants from nutrients in anthropogenic urine. In a continuously operated process, the nutrients were concentrated up to a factor of 3.2. The concentration factor was limited by water transport across the membrane. Water transport was caused by osmosis and electroosmosis, and a model was developed to describe these phenomena. The removal of several spiked micropollutants was investigated in continuous electrodialysis experiments. Ethinylestradiol was removed completely during the whole operating period. Diclofenac and carbamazepine were initially retained, but limited permeation (5-10%) occurred after longer operating times (90 days). Retentions of propranolol and ibuprofen were also high initially, but substantial breakthroughs occurred during extended operation. Considerable adsorption on the membranes was observed for all compounds. The permeation mechanism of several compounds appears to depend on the adsorbed amount on the membrane, which indicates that partitioning and diffusion mechanisms play an important role in the permeation transport. Partial desorption occurred in leaching experiments with polarity reversal, and almost quantitative desorption was observed after incubation of the membranes with Filter Count Gel Solution. Because environmental concentrations are much lower than the concentrations spiked here, it can be anticipated that operation without significant permeation is possible in practice during extended periods of time.

Sorption of pesticide endosulfan by electrodialysis membranes

“…After the feed solution was separated, sorption continued within the diluate and concentrate at pH 7; indicating sorption to both the AEMs and CEMs. This confirms the results by Pronk et al [33] whereby neutral compounds were assumed to sorb to both AEMs and CEMs. Above pH 10, ES degradation results from cleavage of the cyclic sulfite group [10] leading to the formation of ES diol.…”

“…Pronk et al [33] studied the sorption of the hormone 17α-ethinylestradiol (75% initial mass sorbed) to ion-exchange membranes during batch ED experiments for the treatment of urine and postulated that sorption was due to hydrophobicity. However, a study by Banasiak [34] suggested that trace organic sorption (of steroidal hormones) to ion-exchange membranes was influenced by mechanisms other than hydrophobic interactions.…”

Pathogens and pharmaceuticals in source-separated urine in eThekwini, South Africa

“…However, coupling biological nutrient stabilization with the postnitrification steps of distillation and advanced treatment can improve the quality of the liquid fertilizer by inactivating pathogens and removing pharmaceuticals, respectively. Several treatment processes have been successfully tested for the removal of pharmaceuticals from stored urine: ozonation (Dodd et al, 2008), electrodialysis (Pronk et al, 2006a), and nanofiltration (Pronk et al, 2006b). Treatment with activated carbon was shown to be an effective process for pharmaceutical removal from nitrified urine ( € Ozel Duygan et al, 2015).…”

Xenobiotics Removal by Membrane Technology: An Overview

“…The only studies are on the applicability of ED for salts recovery from a urine solution containing xenobiotics [37,105]. Although high removal of 17α-ethinylestradiol is obtained [37], Pronk et al [105] showed that xenobiotics such as CBZ and propanolol readily adsorb on the membranes, where electrostatic, size exclusion and hydrophobic interactions play a role in the adsorption behaviour. More hydrophobic compounds seem to adsorb more.…”