Membrane distillation of NaCl solution containing natural organic matter

The concentration of NaCl solution containing natural organic matter by mem brane distillation (MD) has been performed. The salt solution produced duri ng animal intestines processing was used as a feed. The presence of organic compounds in the feed caused the fouling of MD membranes. The experiments were performed with polypropylene capillary membranes. A rapid flux decline caused by the deposition of organic matter on the membrane surface has bee n observed. The morphology and composition of the fouling layer was studied using scanning electron microscopy (SEM) coupled with energy dispersion sp ectrometry (EDS) and Fourier transform infrared with diffuse reflectance sp ectroscopy (FTIR-DRS). Protein and sodium chloride constituted the major co mponents of the gel layer. Rinsing of the MD module with a 2 wt.% citric ac id solution removed a part of the fouling layer. Boiling of spent NaCl solu tion followed by filtration resulted in the separation of the organic matte r in the form of a deposit. This enabled a significant reduction in the occ urrence of fouling phenomenon. (C) 2001 Elsevier Science B.V. All rights re served.