Reactive dye removal from aqueous solution by sorption on modified ash

Abstract

Effluents of textile dyeing are characterized by intense colour, chemical oxygen demand, suspended solids and a variety of refractory matter, such as heavy metals and nonionic surfactants. Strong colours may reduce light penetration, thus affecting the growth of plants and having impact on invertebrate and other forms of wildlife. There are a large number of methods for dyes removal, such as membrane separation, flocculation, sonolysis, anaerobic biological treatments, oxidative destruction via UV/ozone treatment, photocatalytic degradation, which have certain efficiency but their initial and operational costs are so great. Sorption is one of the several techniques that have been successfully utilized for dyes removal. A large number of materials have been used as suitable sorbents for decolourization of industrial effluents: activated carbon (the most common but expensive adsorbent), polymeric resins, various low-cost adsorbents (agricultural and industrial by-products, peat, chitin, silica, fly ash, etc.) Our investigation presented the preliminary results of the study on modified ash, which has been tested for its use as material with sorptive properties in the recovery of dyes from waste waters. The batch equilibrium of reactive dye Brilliant Red HE-3B sorption on industrial waste, based on ash was investigated in order to explore its potential use as low cost sorbent for wastewater dye removal. The results indicated that the sorption of tested dye depended on initial dye concentration, sorbent mass, pH, temperature and contact time. The sorption of dyes increased with ash dose, dye concentration and temperature increase. Even if the sorption capacity of ash was relatively small, ash could be used for the removal of dyes from aqueous effluents.