화학공학소재연구정보센터
Journal of Chemical Technology and Biotechnology, Vol.77, No.7, 767-770, 2002
The use of chromium waste sludge for the adsorption of colour from dye effluent streams
Adsorption studies show that chromium hydroxide precipitates can be used for the removal of methylene blue, reactive blue, congo red and disperse orange dyes from aqueous media. Three different mechanisms are involved: attraction of positive surface charges on the precipitate at low pH for dye anions (reactive blue and congo red); attraction of negative surface charges on hydroxide at high pH for dye cations (methylene blue), and dye particle entrapment for the neutral disperse orange. The point of zero charge of the chromium hydroxide precipitate based on the dye adsorption studies is pH 10.5. The changes in the surface charge of such precipitates with pH can be used to achieve the removal of any charged dye species.