105-113In the present study, a low-cost adsorbent derived
from Moringa peregrina plant has been used for its ability to remove two
common textile dyes, namely Methyl Orange (MO) and Reactive Red
198 (RR-198) from aqueous solutions. The effect of various operating parameters
such as initial concentration of dye (10-150 mg L-1), contact time
(10-150 min), adsorbent dosage (1-13 g L-1) and pH (2-11) is
investigated. At an optimum pH of 2, approximately 96% removal of dye
(50 mg L-1) is obtained for an adsorbent dose of 7.0 g L-1
after a 70 min contact time. The equilibrium assessment reveals that the
Langmuir model is better than Freundlich model for the experimental data. The
thermodynamic properties (ΔGº, ΔHº and ΔSº) show that the adsorption of RR-198
and MO dyes onto Moringa peregrina tree shell ash (MPTA) is spontaneous,
endothermic and feasible in the temperature range of 293-313 K. Also, the
magnitude of enthalpy change indicates that the adsorption is physical in
nature. Finally it can be concluded that the MPTA can be used as a low-cost
adsorbent for the removal of different concentrations of anionic dyes from
aqueous solutions