An Investigation and Comparison of Removing Heavy Metals (Lead and Chromium) from Aqueous Solutions Using Magnesium Oxide Nanoparticles

Abstract

This study aims to investigate the efficiency of magnesium oxide nanoparticles (MON) in vitro for the removal of lead (II) and chromium (VI) from aqueous environments. The effects of various parameters such as contact time (15 to 280 min), pH (3, 5, 7 and 9), the initial concentration of lead/chromium (10, 20, 30.40 and 50 mg/L), absorbent dose (0.3, 0.5 and 0.8 g/L), and shaking speed (150 to 350 rpm) was investigated. The parameters were optimized by varying one parameter at a time and keeping other parameters constant. The maximum removal efficiency of MON for lead (II) and chromium (VI) was achieved at contact time 280 min, pH 9, initial concentration of lead/chromium 10 mg/L, adsorbent dose 0.8 g/L, and shaking speed 250 rpm. The results also indicated that MON convert the Pb2+ to Pb0and Cr6+ to Cr3+ during the removal process. The adsorption of lead (II) and chromium (VI) follows the Langmuir isotherms, therefore the adsorption was of a physical nature.