Evaluation of Some Eco-Friendly Food Residues for Removal of Methylene Blue Dye from Aqueous Solutions

Walnut shell (WS) powder and eggshell (Eg) powder were grounded and sieved using a 75 µm hole diameter sieve. Both WS and Eg powders were characterized by SEM and IR technologies, and their adsorption capacity was tested towards Methylene blue dye (MB). The tested parameters for MB removal efficiency (RE) were contact time, initial dye concentration, and temperature. It was found that RE of 20 mg/L MB equaled 65.86% after 10 min and 64.82 % after 30 min in the presence of WS and Eg, respectively. For 20, 40, 60, 80 and 100 mg/L of MB, RE using WS equalled to 65.87%, 71%, 71.8%, 72% and 72.34 respectively. However, using Eg, RE for the same concentrations of MB was noticed to be 60.01%, 55.23%, 51.62%, 46.01%, and 44.52%, respectively. At varing temperatures, for 20 mg/L of MB, the RE was 69.34%, 72.5%, 69.44%, and 69.85% at 25, 35, 45, and 55°C on order using WS powder. While at the same temperatures, RE was 64.21%, 65.21%, 65%, and 64%, respectively, using Eg powder. It can be concluded that WS powder has shown greater adsorption capacities towards MB than Eg powder.