Using Ash Prepared from Almond Shell for Removing Acid Red 18 from Aqueous Solutions

Acid Red 18 dye is one of the most consuming dyes used in textile industries causing increased environmental problems. Therefore, it is necessary to treat the wastewater of textile industries before discharging to the environment using effective methods. The aim of this study was to evaluate the removal of Acid Red 18 dye from aqueous solutions using ash prepared from almond shell.
In this experimental study, Acid Red 18 Dye was used as the candidate of Azo dyes. Almond shell was activated using thermal method (ash preparation) and utilized in a batch system in order to remove the dye from the aqueous solutions. Experimental operation was conducted in the following conditions: pH (2-12), contact time (15-20 min), rate of adsorbent (0.2-2 g/l), the initial concentration of dye (25-100 mg/L), and experiment temperature 25±1 °C.
The results showed that the highest rate of removing Acid Red 18 (90%) is obtained from the ash prepared from almond shell at PH 2, contact time 60 min and adsorbent dose 1.6 g/l. In addition, the balance data was fixed to Langmuir & Freundlich isotherm models indicating a better correspondence of the data resulted from the present study with Langmuir adsorption model (R2= 0.9782) than Freundlich adsorption model (R2= 0.9579).
The results of the present study showed that thermal activation of almond shell and its usage in controlled conditions is an effective method for removing Azo dyes from textile wastewaters.