Clay mineral batch process for color removal of textile wastewaters.

Textile industry effluents exhibit large amounts of dye chemicals, which create severe water pollution. It is therefore important to reduce the dye concentration in the wastewater before discharging into the environment. In this study, the ability of sepiolite to uptake different reactive dyes is investigated. The dyes used in the experiments are Everzol Black B, Everzol Yellow 3RS H/C, and Everzol Red 3BS. A number of parameters on adsorption has been investigated in order to establish the adsorption pattern of sepiolite. The effect of conditioning time, solid/liquid ratio, pH, temperature, and dye concentrations on adsorption are studied. Adsorption isotherms for different reactive dyes have been obtained using both natural and modified sepiolites. The maximum capacity of natural sepiolite for the reactive dyes occurs at around 0.1-1 mg/g. Therefore, the natural sepiolite appears to have a little capacity for reactive dyes. The zeta potential profiles of natural and modified sepiolites against pH are also examined. The modified sepiolite exhibited ten times higher performance than the natural sepiolite.