Alumina-Ni composites obtained by sol-gel method as adsorbents of azo dyes

Abstract

The disposal of waters contaminated with azo dyes into natural aquatic recipients can be regarded as very harmful. Since dyes have a high degree of chemical and photolytic stability adsorption can be regarded as appropriate method for dye removal. Porous alumina composites are well known as efficient and inexpensive adsorbents of different pollutants. In this paper, the alumina powders, pure and doped with 40 mass % nickel, were synthetized by sol-gel method and calcined at 500 oC, 900 oC and 1100 oC in order to obtain mesoporous structures with a high specific surface area, well adaptable to adsorption application. The obtained composites were tested as adsorbents of textile azo dye Acid Yellow 99 (AY99). The adsorption was monitored with respect to contact time, using AY99 initial concentrations of 50 mg dm-3, mass of adsorbent mads=50 mg and volume of dye solution V=50 cm3. The adsorption study showed that the adsorption capacity of samples decreased with temperature of calcination and nickel content. The study confirmed the feasibility of using alumina composites as adsorbents for the azo dyes.