Abstract

Vanadium oxide nanoparticles (VO₂-NPs) were synthesized and utilized as an adsorbent against methylene blue (MB) from aqueous environment. Three substantial variables, pH, mixing time, and VO₂ dose, were considered in the process modeling accomplished by Box-Behnken design (BBD). The quadratic model revealed that the VO₂-NPs dose plays the most significant role. The model optimization predicts a 96.3% MB removal when pH, VO₂ NPs dosage, and contact time were adjusted to 6, 0.5 g/​L, and 30 min, respectively. The sorption capacity of VO₂-NPs raised rapidly from 49.6 mg/​g to 235.7 mg/​g by increasing the initial MB concentration from 25 to 200 mg/​L, respectively. The best fitted kinetic model was the pseudo-second order, while the well fitted Langmuir model showed a q_max of 240.5 mg/​g. The study of the temperature effect revealed that increase of the temperature had a positive impact on the removal efficiency.