Thallium (Tl) contamination is of main concerns due to its high toxicity in the environment. To date, Tl adsorption is critical but limited by less knowledge on the designing and application of cost-effective and potential materials for its removal. In this work, a montmorillonite biochar composite (MMT-BC) was synthesized from biochar (BC) and montmorillonite (MMT). It was characterized to know its Tl’s adsorption mechanisms and was evaluated for its ability to remove Tl through batch adsorption experiments. The results showed that MMT-BC had a higher Tl removal rate than BC and MMT. The adsorption fitted well the Freundlich model with the highest adsorption capacities of MMT-BC (79.7 µg/g), which was higher than 69.8 µg/g of BC and 67.1 µg/g of MMT at 800 µg/L of the initial concentration. Ion exchange, electrostatic attraction, and complexation were the main processes influencing Tl adsorption onto MMT-BC. Furthermore, MMT-BC manifested a higher removal percentage of 95.85% under high ionic strength and high selectivity of 95.15% and 93.66% towards Tl in co-existence with Cu²⁺ and Pb²⁺, respectively. The desorption percentage was 89.4%, 83% and 98.9% for BC, MMT and MMT-BC, respectively. Therefore, our findings highlighted that MMT-BC is a potential material for controlling Tl contamination in the environment.

Cyubahiro, E., Luo, Z., Kayiranga, A., Habumugisha, T., Nkinahamira, F., Ndayishimiye, J. C., Yan, C., Wang, Z. (2022). Thallium removal by the montmorillonite biochar composite: insights and environmental implications. Desalination And Water Treatment, 253, 177–193. DOI: 10.5004/dwt.2022.28301.