CERAMIC FILTERS WITH EMBEDDED MESOPOROUS SILICA FOR HEAVY METAL REMOVAL FROM WATER ()

摘要

The invention relates to a ceramic filter impregnated in its pores with mesoporous silica particles having the property of retaining heavy metals from waste water and to an impregnation process. According to the invention, the filter is a candle-type filter which exhibits two porosity types: an internal porosity (3) of the ceramic material in the range of 2...4 μm and an external porosity (2) of 0.3...0.7 μm, the thickness of the two layers (2 and 3) being of 5 mm for each layer, which does not have applied coatings or other chemical or thermal treatments, the filter length and diameter being variable, depending on the plant in which it is meant to be mounted, which is provided with a tight cover (4) with a water supply connection (5) at its top. The process, as claimed, comprises two impregnation procedures: a. impregnation during the synthesis, by forcing the mesoporous silica gel to enter the ceramic filter pores (3) by application of an external pressure, after which the filtering assembly is subjected to a hydrothermal treatment at 100°C for 24 h, is washed with distilled water up to a leachate pH of 7, dried at the ambient temperature and then calcined at a temperature of 550°C for 5 h; b. after the synthesis, the calcined mesoporous silica is mixed up to homogenization with a sufficient amount of distilled water, the resulting solution being then forced to enter the pores (3) of the ceramic filter up to complete charging of the internal ceramic layer pores of the filter, by application of an external pressure, depending on the filter operating parameters and, in the end, the entire filtering assembly is subjected to a heat treatment, at a temperature of 105°C, for its complete drying.