Adsorption Mechanism of Sodium Dodecyl Sulfate on Coagulating Precipitate in Treatment of Vat Dark Blue BO by Coagulation and Air-flotation

摘要

Vat dark blue BO simulated wastewater was treated by Dissovled air flolation(DAF), the interaction of sodium dodecyl sulfate (SDS) and precipitate in the DAF process was investigated by thermodynamic methods. The adsorption isotherms of SDS on precipitate at pH 5.00 were determined at 30,35,40 and 45°C. The isosteric heat of sorption was calculated by the Clausius-Clapeyron equation. The results show that the isotherm of SDS on coagulation precipitate is not the normal style, the adsorption of SDS on precipitate is exothermic in nature and the isosteric heat of adsorption decreases with a increase in the equilibrium uptake of SDS on precipitate. The isosteric heat of sorption varies between -16.266 and -21.719kJ/mol as surface loading is between 3 and 11 mg/g. The values of isosteric heat of adsorption proves the primary adsorption of SDS on precipitation is physisorption.