The discharge of dye in industrial effluents is of great concern because their presence and accumulation have a toxic or carcinogenic effect on living species. The removal of such compounds at such low levels is a major difficult problem.The filtration and separation technique and few natural absorbing materials like clay, charcoal, and adsorption on activated carbon, manganese oxide, and silica gel can be used for adsorption of these harmful dyes. The adsorption process is an effective and attractive proposition for the treatment of dye contaminated wastewater. Adsorption techniques have proven successful in removing colored organic species with activated carbon being the most widely used adsorbent due to its high capacity for the adsorption of organic materials.

However, it is expensive and the powdered one is difficult to be separated from aquatic system when it becomes exhausted or the effluent reaches the maximum allowable discharge level. The regeneration of exhausted activated carbon by chemical and thermal procedure is also expensive and results in loss of the sorbent. Cationic dye molecules also have very high affinity for clay surfaces and are readily adsorbed when added to clay suspension.

The elimination of the organic dye by clay was studied by several researchers. The adsorption of the dye can be done on a large area with the help of fixed bed models and in order to improve the adsorption of the basic dyes we need to know the basic model making and it will be possible to predict the performances and the characteristics of the operating conditions.

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