Adsorption of chromium (VI) ions from aqueous solution on activated carbon prepared from Centella asiatica leaves

Abstract

The adsorption ability of activated carbon derived from Centella asiatica leaves to eliminate Cr (VI) ions is explored in this research. The batch mode method has been used to examine the adsorption process as a function of pH (2 to 10), contact time (10 to 90 min), adsorbent dose (25 to 150 mg/g), temperature (30 to 60oC) and initial concentration (10 to 50 mg/L). The isotherms (Langmuir and Freundlich) and kinetic models (pseudo-first-order and pseudo-second-order) were used to test the adsorption data. The obtained findings suggest that the highest percentage of Cr (VI) ions removal (80%) was achieved at contact time (90 min), pH 6, adsorbent dose (100 mg/g), initial concentration (10 mg/L) and temperature (300C). The Langmuir isotherm equation showed better fit. The rate of adsorption was found to confirm pseudo-second-order kinetic model.