## 1 Introduction
### Role of Released Cations during Filtration  
The Israeli Health ministry issued a conditional permission to apply the micelle-clay technology for treatment of drinking water and unrestricted irrigation, provided that the concentration of the released cation, e.g., ODTMA, would not exceed 100 \(\upmu\)g/L. The concentrations of released ODTMA during filtration of 100 m\({}^{3}\) of water by a pilot filter filled with granulated complex ODTMA-clay were between 25 and 50 \(\upmu\)g/L [12]. Using a small column (1.6 cm \(\times\) 20 cm) filled with granulated complexes followed by a similar one filled with activated carbon indicated that after passing 64 L, the concentrations of released ODTMA and BDMHDA cations were 82 and 1817 \(\upmu\)g/L, respectively; whereas, after passing through the second (GAC) filter, the corresponding values were reduced to 1.6 and 0.9 \(\upmu\)g/L [13]. Significantly more release of BDMHDA than ODTMA has been found earlier for the powdered complexes [14].  
[PERSON] et al. [13] pointed out that the BDMHDA-clay complex had an advantage over the complex based on ODTMA in reducing the number of emerging bacteria, despite similar numbers of bacteria retained by the filters, which included fresh or regenerated complexes. Designed experiments supported a hypothesis that the advantage of BDMHDA-clay over ODTMA-clay complexes in removal of bacteria from water was due to larger concentrations of released BDMHDA than ODTMA cations during filtration. It was suggested that the relatively larger numbers of released BDMHDA cations exert a much larger biocidal or biostatic effect on the emerging bacteria than in the case of ODTMA. This effect was seen both with E-_coli_ or total bacteria count (TBC). For the purpose of water purification, the biostatic effect by free monomers is sufficient. [PERSON] et al. [15] demonstrated that small concentrations of free ODTMA cations abolished the photosynthetic activities of two cyanobacteria, _Microystis aeruginosa_ and _Aphanizomenon ovalisporum_, which amounted to cell killing.  
The main aim of the current study is to test variations in composite composition to enhance the capacity for removal of (1) bacteria and (2) neutral hydrophobic pollutants.  
1. An increase in concentration of released cations, which is expected for composites formed with a larger added amount of cation per clay than in the ordinary one [12,14], will result in a larger biocidal/biostatic effect and enable the micelle-clay complex to remove more TBC from water by filtration. The tests will involve a synthesis of a granulated complex obtained by adding the salt of ODTMA at a larger ratio to bentonite than in the ordinary complex during preparation of the complex.
2. In the case of optimization of removal of neutral hydrophobic pollutants. the tested modification will deal with both the micelle-clay and liposome-clay [12,14,16] composites. Liposome-clay complexes are similar to the micelle-clay ones but are prepared by adsorption on the clay of vesicles whose alkyl ammonium surfactants have two long alkyl chains. In this case, the concentrations of monomers in solution are significantly smaller ([PERSON] et al.) [17] than those of micelle-forming surfactants with one long alkyl chain of the same length. As an example, the surfactant dodecyldimethylammonium bromide (DDAB) remains in solution as monomers up to 35 \(\upmu\)M [18], whereas the CMC of dodecyltrimehylammonium bromide is 3.49 mM [19].  
Removal of neutral hydrophobic molecules from water by a composite micelle (ODTMA)-clay, or liposome (DDAB)-clay is not expected to increase by loading the cation beyond neutrality of the clay. If this is confirmed, then, for removal of neutral hydrophobic pollutantsfrom water, the synthesis of clay composites can be accomplished with one third less of the amount of the organic cation, which is the expensive component. The tests by filtration, will compare the efficiency of pollutant removal by an ordinary (positively charged) vs. neutral clay composite.