ABSTRACT
The dyestuff manufacturing and textile industries consume a high volume of water and produce a great amount of wastewater containing various toxic substances. Different methods are used to remove dye compounds from wastewaters. Removal of dyes from water by adsorption processes received considerable attention and a number of studies focused on the adsorption of some dyes by non-conventional low cost and effective adsorbents. In this study, the suitability of the canola stalks for acid orange 7 adsorption was assessed. The dry canola stalks obtained from the research farm were milled and screened and the particles size ranged between 0.4-0.7 mm were used in all experiments. Acid orange 7 supplied by Alvan Sabet. Initially, the effects of initial dye concentration, pH and temperature on adsorption were examined. The kinetic and equilibrium data obtained for various concentrations of evaluated on the basis of Langmuir and Freundlich isotherms. The results showed that the absorption efficiency depended strongly on pH and slightly on the temperature. Absorption of acid orange 7 on ne canola stalks was fairly rapid and more than 95% of adsorption occurred within the initial 5 minutes of the treatment. Both Langmuir and Freundlich models were applicable for the description of acid orange 7 dye adsorption by canola stalks. According to the Langmuir model, the highest capacity of canola stalks for acid orange 7 adsorption was found 24.8 mg/g which was higher than the capacity of beech wood sawdust and soil mixture with fly ash