Removal of dissolved contaminants, by using a suitable extracting solvent.
The water flow and the solvent stay completely separated by using a membrane. The solvent flow is in principle much smaller than the water flow (approx. factor 1000 or more). Description including main features/advantages The water flow and the solvent flow move counter currently through one or more membrane modules. The counter current modus may result in very high removal of the contaminant using very low amounts of solvent. Commercial membrane modules are preferred for a cost effective process. Selection of best type of solvent may need laboratory experiments and market evaluations. Typically, one prefers: a) low cost solvent in the case waste disposal is required (incineration) b) a solvent which allows recycling/recovery in the process (e.g. by distillation) c) a solvent to produce a valuable product In order to reduce cross contamination of the water with the solvent, the solvent should show very low water solubility. In a specific variant of the process, the membrane acts as an air gap. This variant is only suitable for (very) volatile contaminants, such as halomethanes. But also it is also suitable for ammonia (after pH adjustment). Innovative aspects Ease of separating the two phases, when compared to conventional extracting processes. Foaming and other operational problems are avoided. Very low energy requirements for the ‘mixing’ step. Current and potential industrial users/domains of application Various applications may be found in chemical industry. Current state of development First applications have been successfully introduced in the market: - recovery of valuable chemicals by using an common solvent in chemical industry - recovery of ammonia from wastewater Contact details Organisation TNO Website www.tno.nl/water Contact person A. Jansen Address P.O. Box 342 7300 AH Apeldoorn Phone +31 88 8662179 Fax Email Albert.email@example.com