Various Methods for Removal of Dyes from Industrial Effluents - A Review

Objectives: To explore most suitable and efficient method for the removal of dyes from textile effluent. Methods/ Statistical Analysis: In this paper, scattered information of research work carried out by many researchers related to various methods for the removal of cationic dyes especially Rhodamine-B, Methylene Blue, Crystal Violet, Malachite Green and Safranin-O dye present in textile effluent have been compiled and compared to find out cheap and effective method by calculating their percentage removal. Findings/Recommendations: It has been found that among all the methods reported so far, Adsorption process show promising results and overcomes almost all the demerits of otherwise efficient methods like advanced oxidation and electro coagulation etc. in terms of high cost and sludge problem. So ,the use of natural adsorbents and agricultural/industrial waste materials especially modified flyash, red mud ,activated rice husk , surfactant modified alumina, bentonite clay as adsorbents is recommended for the removal of cationic dyes since they are of less cost/ no cost, easily available and have great affinity for dyes. Moreover, agriculture/industrial waste often poses a disposal problem. So, their use (after chemical treatment) as adsorbent is environmental friendly. Applications/Improvements: This review paper would be helpful to find the most promising method for the removal of cationic dyes from the textile effluent considering the merits and demerits of each method. Much work has been done to explore the most effective and cheap method for the removal of dyes recently but not under the range of operating conditions. In future, more methods need to be explored to study and check removal of dyes from real textile effluent at the industrial level as the dye effluent also contains other harmful pollutants. Attention is to be paid to develop cheaper and more efficient adsorbents from the agriculture/ industrial waste with some modification which would be cost effective. Moreover, management of exhausted adsorbents is also to be taken care of.