Decolourisation of Synthetic Dyes by Agricultural Waste- A Review

Decolourisation of waste water has now become a major problem for the treatment plants in various industries. Many industries use synthetic dyes to colour their products such as textiles, rubber, paper, plastics, leather, cosmetic, food etc. Nearly 10-15% of synthetic textile dyes, used yearly are lost to waste streams and about 20% of these losses enter the environment through effluent from waste water treatment plant. Numerous techniques were used in the recent past for decolourisation of dyes. Among them adsorption technique has got maximum potential for the removal of dyes. Adsorption being a physical process, in-expensive and less time consuming, is widely accepted. It is evident from last 20-25 years that many researchers have studied the feasibility of low cost adsorbents derived from natural material, industrial material, agricultural waste and bioadsorbents and resulted in innovative approach in this area. The current research is focussed on the need to develop an efficient adsorbent with cost effectiveness and high potentiality. From the survey of about 80-85 research papers, it was concluded that low cost adsorbents obtained from agricultural waste products were found to be having outstanding removal capabilities. This paper reviews the suitability of both raw and chemically modified agricultural products in the decolourisation of synthetic dyes.