Abstract:
Dyes are extensively used to color various products in many industries. These can be lost as
effluent to the aquatic environment. The waste water Loaded with toxic dyes is not acceptable to
environmental regulations and exhibit to humans, aquatic organisms, and the environment in
general. Based on this idea, focusing environmental issue and economic point of view, the use of
low cost and eco-friendly food wastes were investigated for the removal of MB dye from waste
water. In this study, the usage of food wastes like Injera, peels of potatoes, onions, and garlic
adsorbents (acid activated biochar) for the removal of MB dye from the aqueous solution were
investigated. Some physicochemical properties of the adsorbents such as porous characteristics,
surface area, surface functional group and point of zero charge were determined. The batch
adsorption studies of methylene blue were carried out by Injera, peels of onion, garlic, and
potatoes wastes independently. The optimum removing efficiencies of potato, garlic and onion
peels activated biochars were known to be 99.213% at optimum (initial concentration of 10
mg/L, temperature of 313 K, pH of 10 of mass of 0.5 g and time of 180 minutes), 99.833% at
optimum (initial concentration of 10 mg/L, temperature of 313 K, pH of 7 of mass of 0.1 g and
time of 30 minutes), and 99.994% at optimum (initial concentration of 10 mg/L, temperature of
343 K, pH of 4 of mass of 0.4 g and time of 20 minutes) respectively. The modeling studies
revealed that the studied process obeys the pseudo-second-order model and Langmuir isotherm
model. Finally, the determination of thermodynamic parameters indicated the exothermic and
spontaneous type of the removal process of MB onto all activated biochars prepared.
