Removal of Reactive Red 2 and Methylene Blue from Aqueous Solutions by Adsorption Using Soybean Meal as Adsorbent

The removal of reactive red 2 and methylene blue from aqueous solution was studied using soybean meal as an adsorbent. The effects of some parameters such as solution pH and contact time on the adsorption were investigated. The equilibrium time was found to be more than 60 min for equilibration. Equilibrium data conformed to the Freundlich, Langmuir and Redlich-Peterson isotherm models, where the maximum adsorption capacity of methylene blue was 50.2 mg g-1 for the Langmuir isotherm at 25°C, but the maximum adsorption capacity of reactive red 2 was low (16.4 mg g-1). Soybean meal, which are easily available and inexpensive, could be employed as a promising adsorbent for the removal of methylene blue, but not for reactive red 2.