Author Description

This book focuses on water purification by micelle-clay nano-particles. The micelle-clay complex is composed of an organic cation (surfactant) with a long alkyl chain, e.g., ODTMA (octadecyltrimethylammonium) that spontaneously forms micelles of several nm in diameters at small concentrations. The positively charged micelles interact with a negatively charged clay (bentonite) at optimal ratios. The resulting complex has a large surface area per weight; it includes large hydrophobic parts and has an excess of a positive charge. The complex is insensitive to higher temperatures (50 0C), to pH values in the range of 2-11, or ionic strengths. Production of powdered and granulated complexes is described. The material characteristics of the micelle-clay complex differ from those of organo-clay of the same composition, which is formed by the interaction of monomers of the surfactant with the clay (Chapters One and Two). Model calculations enable simulations and predictions of removal of pollutants from water in batch or filtration experiments, and can yield cost estimates (Chapter Three). Laboratory and pilot experiments (Chapter Four) yield efficient removal from the water of (i) hydrophobic and anionic organic molecules: herbicides, humic acid, dissolved organic matter, and pharmaceuticals; (ii) inorganic anions, e.g., perchlorate; and (iii) microorganisms: bacteria, viruses, and parasites, e.g., cryptosporidium, which is resistant to chlorination. The (above) use of a micelle-clay complex indicated a big advantage in comparison with activated carbon. Low cost regeneration of used filters after bacteria adsorption is described. Biocidal effects of cations, e.g., ODTMA are demonstrated; released cations during filtration enhanced the filter efficiency. The released cations are removed from water before consumer use by another filter containing activated carbon. Drinking water from lakes is forbidden during cyanobacteria bloom due to harmful toxins. Filtration by the granu