Thongkam, Thinikan, Khuanjit Hemavibool, Jintana Klamtet, and Sairoong Ouypornkochagorn. “Potential Adsorption of Leonardite for Heavy Metal Ions Removal from Aqueous Solution”. Science Essence Journal 36, no. 1 (June 26, 2020): 177–188. Accessed November 10, 2024. https://ejournals.swu.ac.th/index.php/sej/article/view/11524.