Organic matter removal with bicarbonate-form ion exchange: water quality, kinetics and mass transfer mechanisms

Impact of resin loading on ion exchange equilibrium for removal of organic matter and inorganic ions

“…To test the applicability of the model to predict IEX equilibria in a multicomponent system at increased resin loading, experimental data from 15 jar tests where the resin was reused without regeneration was used. The data was taken from the work of Fernandez et al (2021b) and includes results for 15 consecutive suspended IEX jar tests using water from a lowland river in the UK with no resin regeneration (Table S1).…”

“…Previous research has shown that bicarbonate reduces the corrosivity of the treated water and has shown promising results at lab scale when used as an alternative regenerant (Rokicki and Boyer, 2011;Fernandez 2021b). Another potential way of reducing the treated water corrosivity is by decreasing the regeneration frequency of the IEX process (resin reuse), which would also allow for reductions in brine and waste volumes.…”

“…When the IEX resin is reused over more than one treatment cycle before regeneration, more than one ion will occupy the active sites of the resin. These ions become presaturant ions which may exchange with counterions in subsequent treatment cycles in secondary IEX (Fernandez et al, 2021b). The challenge is then to model this multiple exchange…”

Revealing the effect of anion exchange resin conditioning on the pH and natural organic matter model compounds removal mechanisms

“…Furthermore, most studies use resins in the counter ion form as delivered by the manufacturer, which is usually the Clform for SBA and the free base (FB) form for WBA resins. However, when ion exchange is the dominant removal mechanism, the counter ion can have an important influence on the removal efficiency due to difference in selectivity of the counter ion for the (anionic) NOM, caused by the differences in ionic radius and corresponding resin swelling pressure [32,33]. In the past few years, the effect of varying the counter ion on NOM removal has been investigated.…”

“…Researcher are looking for alternatives on the classical regeneration procedures to the Clform using brine to, with the aim to e.g. reduce brine generation or lower the risk of (pitting) corrosion caused by the released Cl-ions into the treated water [33][34][35][36]. The cationic and anionic resins applied in a water demineralization unit, are in the H + , resp.…”