Abstract

Arsenic (As) is one of the worst toxicants among trace elements, adversely affecting human beings. The removal of arsenic from aqueous solutions was studied using Melia azedarach sawdust modified with FeO (MSFeO) as the adsorbent. Arsenic removal was experimentally conducted using MSFeO, based on different parameters including pH (2.77-11.23), time (23.47-171.52 min), the concentration of arsenic (0.04-1.16 mg/L), and adsorbent dose (2.95-17.05 g/L). The characteristics of the synthesized adsorbent were also determined via scanning electron microscope imaging and Fourier-transformed infrared technique. The results indicated that the maximum removal efficiency of As (70.7) occurred under 0.2 mg/L initial arsenic, 15 g/L adsorbent, pH 4, and contact time of 15 min. The adsorption process was well fitted with the Langmuir model for the majority of samples tested. The experimental data were suitably fitted by the pseudo-second-order kinetic model. The results confirmed that the adsorption rate of arsenic had a direct relationship with the adsorbent dose, contact time, and pH and an inverse relationship with the initial concentration of arsenic.