Sorption of Acid Yellow 23 from aqueous solutions onto soil

Acid Yellow 23, an anionic azo dye, also known as Tartrazine,FD&C Yellow 5, CI 19140 or E102 (in Europe) is widely used in medicine or cosmetics, foodstuff and textile industries. In pharmaceuticals, Acid Yellow 23 is incorporated as additive in medicines, antacids, vitamin supplements, whereas in cosmetic industries, it is utilized in hair dyes, soaps, lotions, shampoos, bath gels, skin-care creams, deodorants, lipsticks and many others. Due to its very wide use for different purposes, Acid Yellow 23 may be commonly found in municipal wastewaters or wastewaters riginating from textile, food, drugs and cosmetic industry.In this context, it may also result in negative impact on he environment through discharge of improperly treated wstewaters in receiving waters. In this work, the capacity of a Romanian soil to retain Acid Yellow 23 from aqueoussolution by sorption has been investigated. The Freundlich,Langmuir and linear isotherm models were applied to describethe process and the parameters of these equations were calculated. The sorption kinetics was investigated by applying five kinetic models aiming at establishing the model that best fits the sorption of the azo dyes onto the particles of investigated soil.