Removal of some organic dyes by acid-treated spent bleaching earth

Aid treated spent bleaching earth was prepared by treating spent bleaching earth, a waste material from the palm oil industry, with 20% sulphuric acid and heated at 350 degrees C for three hours. This material can efficiently sorb a variety of organic dyes especially reactive and acid dyes, with max imum sorption capacity in the order of 2-300 mg g(-1). The applicability of both the Langmuir and Freundlich isotherms to the experimental data indica tes that both physicosorption and chemisorption were involved in the sorpti on process.