Bahari Alias, Azil, et al. “Effect of Sorbent Weight on H2S Removal by Biochar and Hydrogel Biochar Derived from Rice Husk”. International Journal of Engineering & Technology, vol. 7, no. 4.18, Nov. 2018, pp. 359-63, https://doi.org/10.14419/ijet.v7i4.18.21957.