Treatment of Textile Dyeing Effluent Using Agriculture Waste Based Adsorbents - A Review

Abstract

Objective: Removal of colour from the textile dyeing effluent is a major problem due to high tinctorial value, complex structure of the dyes, toxicity and presence of metals in some dyes. The colouring matter has to be removed from the effluent before its discharge as it constitutes the major fraction of pollution. The spent dyes in the textile effluent have to be removed before disposal as they constitutes major fraction of pollution. Review of waste based adsorption of the spent dyes, performance, economics involved and disposal options for the spent adsorbents are the objectives of the present work.
 Methods: Various techniques are used for the removal of colour including adsorption. Although the activated carbon is an ideal adsorbent, it is expensive for effluent treatment due to its high production and regeneration costs. High cost of activated carbon has led to the search for alternate non-conventional adsorbents. Attempts have been made by researchers to use the non-conventional, low-cost and naturally occurring waste materials as adsorbents. The findings are based on literature survey and authors’ experience.
 Findings: This review seeks to give an overview of the agriculture waste based adsorbents together with physical and chemical processing needs, adsorption parameters including mechanisms and the adsorption potential of various adsorbent-adsorbate systems for removal of different dyes from the effluents. Comparative studies conducted with synthetic effluents as well real textile dyeing effluent are also included. The cost involved in the dyeing effluent treatment is always a concern for the textile dyeing industries. The cost issue can be addressed using the waste based adsorbents for which an economics have been presented.
 Conclusion: The gaps between practices and the present research works have been identified and highlighted along with further research needs for treatment of the dyeing effluents. The waste based adsorbents are mainly agricultural residues and combustible. The spent adsorbents can be reused as fuel in the boiler furnace that can offset the expenses on fuel to some extent.