Use of dairy sludge for the removal of some basic dyes
Dairy sludge, which is produced as a result of the activated sludge process, used in the dairy processing industries for treating their effluents, is a low cost, locally available and relatively new adsorbent. It is being investigated for its capacity to remove some of the basic dyes such as aniline blue, crystal violet, malachite green, methylene blue, rhodamine-B, and safranine from aqueous solutions. The effects of various experimental parameters; initial pH, dye concentration, sorbent dosage, ion strength, and contact time, were examined and optimal experimental conditions were decided. At initial basic pH of 10, all six of the dyes studied could be removed effectively and in a very short period of time of just 35 min. The isothermal data for adsorption followed the Freundlich and Langmuir models. The adsorption results in this study indicated that all the dyes studied in this work can be easily removed by the application of dairy sludge.