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Ion exchange membranes could provide a solution to the selective separation of organic and inorganic components in industrial wastewater. The phenomena governing the transport of organics through the IEM however, are not yet fully understood. Therefore, the transport of trace organic contaminants (TOrCs) as a model for a wide variety of organic compounds was studied under different conditions. It was found that in the absence of salt and external potential, the chemical equilibrium is the main driver for TOrC-transport, resulting in the transport of mainly charged TOrCs. When salt is present, the transport of TOrCs is hampered in favor of the NaCl transport, which shows a preferential interaction with the membranes due to its small size, high mobility and concentration. It is hypothesized that electrostatic interactions and electron donor/acceptor interactions are the main drivers for TOrC transport and that transport is mainly diffusion driven. This was confirmed in the experiments with different current densities, where the external potential seemed to have only a minor influence on the transport of TOrCs. It is only when the salt becomes nearly completely depleted that the TOrCs are transported as charge carriers. This shows that it is very difficult to get preferential transport of organic compounds due to the diffusive nature of their transport.

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Fresh water becomes a limited resource in the industry. In order to help chemical industries use other water sources and close their water cycle for the production of steam, a well-founded insight on the challenges and possibilities of switching from one specific water quality to another is needed. A case study for Monsanto Europe N.V. was carried out, but the main findings hold for many more applications, as many industries struggle with water scarcity and feel the need to reuse wastewater. Besides demineralization by ion exchange (IEX), the total organic carbon (TOC) concentration, composition, and the formation of organic acids under boiler conditions were investigated for two different water qualities (Antwerp tap water and wastewater after reverse osmosis (RO) treatment). The comparison included the effect of TOC composition on its removal by IEX and the potential corrosiveness of TOC compounds. Despite tap water showing a more efficient and higher TOC removal compared to RO permeate (93% and 57%, respectively), tap water led to more organic acid formation under boiler conditions. Including the composition of the organic matter in TOC corrosiveness assessment may offer multiple advantages, not in the least economic benefits, when less treatment is required in order to meet the TOC limit value.

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