Application of carbon aerogel for electrolytic removal of mercury from aqueous solutions

Abstract

A study has been carried out to determine the feasibility of electrochemical removal of mercury ions from aqueous solution using carbon aerogel electrodes. In this work the influence of three parameters viz., initial concentration (2-8 mg/L), pH (2-9), and charge (0.3-1.3 Ah) on the percentage removal of mercury are examined using response surface methodological approach. The metal ion removal significantly increases at slightly acidic and high charge conditions. This technique can achieve more than 96 per cent of mercury removal under optimised conditions of high charge (1.3 Ah) and pH 5.5. However, under highly acidic conditions, electrostatic repulsions caused by H⁺ions lead to lower mercuric ion removal. The experiments are statistically designed using box-behnken experimental design model. This model is also used to derive a second order polynomial equation, which can be used to optimise the key parameters for maximising the removal percentage. <i style="">R</i> ² value of 0.9762 is obtained from the regression analysis. This shows a close fit between the experimental results and model predictions.