Alumina-silica-titania adsorbent for hazardous azo and phtalocyanine dyes removal from textile baths and wastewaters – the impact of ionic surfactants

Two aspects of interfacial phenomena were discussed in the manuscript. The first one concerns the adsorptive removal of two azo dyes such as C.I. Acid Yellow 219 (AY219) and C.I. Direct Yellow 142 (DY142) as well as the phtalocyanine C.I. Reactive Blue 21 (RB21) on the alumina silicatitania oxide (4% wt. $Al_2O_3$ – 8% wt. $SiO_2$ – 88% wt. $TiO_2$; AST88) in the ionic surfactants presence. The second one deals with the determination of interaction mechanism in the dyes-AST88, dyes-surfactant-AST88 systems using the data obtained from the surface charge density and zeta potential studies. The sodium dodecyl sulphate (SDS) with anionic character and hexadecyltrimethylammonium bromide (CTAB) with cationic ones were used. The adsorption capacities of 205.2 mg/g for AY219, 36.5 mg/g for RB21 and 18 mg/g for DY142. The potentiometric titration and Doppler laser electrophoresis methods enable determination of sign and magnitude of charge located in both the surface and the slipping plane layers around the solid particles. The structure of electrical double layer was determined in the AST88 systems without as well as with dyes and with mixed dye + surfactant adsorbates.