One of the major environmental problems is the existence of dye materials in water sources. This pollutant must be removed from water by appropriate methods. Although most of these methods are efficient for the treatment of waters contaminated with dye pollutants, they are very costly and commercially unattractive. Adsorption is one of the most popular methods for the removal of dye pollutants from water especially if the sorbent is inexpensive. Sorbents are classified as natural sorbents, commercial sorbents, and the sorbents obtained from industrial and agricultural wastes. Although commercial activated carbon is widely used in wastewater treatment applications, it is very expensive. In this study, usability of inexpensive materials like sepiolite as natural adsorbent, and walnut shell and hazelnut shell as agricultural wastes were investigated instead of commercial activated carbon to remove some azo dyes (methyl red, methyl orange and methyl yellow) from aqueous solution. Batch experiments were carried out to determine the effect of different adsorption parameters such as pH, initial dye concentration, contact time, adsorbent dose and temperature. The equilibrium of adsorptions were modeled using Langmuir and Freundlich isotherm models. Comprehensive study shown that these alternative adsorbents had sufficient binding capacity to remove these azo dyes from water.
- activated carbon
- azo dyes
- dye adsorption
- hazelnut shell
- walnut shell
- First received 14 December 2016.
- Accepted in revised form 31 March 2017.
- © IWA Publishing 2017