Thesis (MSc) - Cyprus International University. Institute of Graduate Studies and Research Environmental Sciences

The carob waste is an eco-friendly, economical, and effective adsorbent however it
has never been studied before for removing pesticides from water. This study
examined the possible application of carob waste powder treated with potassium
hydroxide (KOH) as a substitute adsorbent for removing methidathion pesticide from
water. The adsorbent was characterized by X-ray diffraction, Brunauer-Emmett-
Teller, Fourier-transform infrared spectroscopy, Scanning electron microscope (SEM)
and particle size analyser. pH, adsorbent dose, contact time, temperature, and initial
concentration of methidathion pesticide were among the experimental factors that were
elucidated.
The results showed that solution pH 5 and 2 g/L adsorbent dose were the optimum
conditions at an equilibrium time of one hour and 25 °C. Linear isotherm had the best
fit to the experimental data with a correlation coefficient R2 of 0.95 and pseudo second
order described the kinetic data well with an R-square ≥ 0.98223. The adsorption
capacity of the adsorbent increased with the increasing temperature indicating an
endothermic process. The highest amount of methidathion adsorbed by the KOH
treated carob waste was recorded as 21.3 mg/g comparable and higher than the
adsorption capacity of alternative sorbents reported in the literature. Although the
adsorption process requires further optimization, the findings revealed that KOH
treated carob waste show to be a promising adsorbent for the removal of pesticides
from aqueous solutions.