R. Chaudhari, Archana, et al. “Uptake of Heavy Metal Ions by Carbonaceous Material Obtained from Industrial Waste Lignin Using Microwave Irradiation ”. Asian Journal of Chemistry, vol. 15, no. 2, Mar. 2010, pp. 917-24, https://asianpubs.org/index.php/ajchem/article/view/21720.