Sonochemical immobilization of MnO2 nanoparticles on NaP-zeolite for enhanced Hg (II) adsorption from water

MnO2 nanoparticles were loaded on NaP-zeolite sonochemically to assess their efficiency for mercury removal from water, and the substrate was synthesized via hydrothermal conversion of clinoptilolite. The ultrasonic waves supplied the reaction temperature and provided loading homogeneity. The influence of nanoparticle loading, concentration of potassium permanganate solution, and concentration of hydrochloric acid were investigated on the surface area and adsorption capacity of the product. The optimal synthesis conditions were obtained with ultrasonic waves, 15 wt% MnO2 loading, 0.05 mol.L-1 KMnO4 solution, and 36 wt% HCl concentration. The microscopic images showed that the ultrasonic-assisted method resulted in nano-sized (< 10 nm) and uniformly distributed MnO2 particles on the surface of the substrate. Compared with conventional loading, the ultrasonic one resulted in 24.4 % and 8.5 % improvement in BET surface area and removal efficiency, respectively. The dynamics of adsorption from water at a very low initial concentration of mercury (10 mu g.L-1) and the influence of competitive copper ions were investigated. The dual nature of ultrasonic waves helped synthesize a cost-effective adsorbent that fulfills the need for high quality drinking water at a large scale.