Quynh, et al (2024) Comparison of In-situ Mixing and Capping Techniques of Activated Mulberry Biochar for Interrupting the Release of Hexavalent Chromium and Naphthalene from Contaminated Sediment

Contaminated sediments with hexavalent chromium (Cr(VI)) and naphthalene (NAP) pose significant environmental risks. Recent research has explored the use of activated mulberry biocharBiochar is a carbon-rich material created from biomass decomposition in low-oxygen conditions. It has important applications in environmental remediation, soil improvement, agriculture, carbon sequestration, energy storage, and sustainable materials, promoting efficiency and reducing waste in various contexts while addressing climate change challenges. More (MBK) treated with alkali (K2CO3) to stabilize these contaminants. MBK boasts a substantial specific surface area of 2213 m²/g, demonstrating high sorption capacities of 340.1 mg/g for Cr(VI) and 250 mg/g for NAP.

Sorption kinetics and thermodynamics indicated rapid equilibrium, with higher temperatures enhancing the sorption process for both contaminants. Additionally, the presence of dissolved organic matter (DOM) at environmentally relevant concentrations further improved MBK’s sorption efficiency. While low concentrations of Cr(VI) did not impact NAP sorption, higher levels inhibited it.

The study evaluated two sediment amendment techniques: in-situ mechanical mixing (MIX) and in-situ capping (CAP). Both methods effectively reduced the flux of Cr(VI) and NAP from water to sediment by 99%. However, the MIX technique outperformed CAP in reducing contaminant concentrations in pore water.

Overall, MBK proved more effective in stabilizing Cr(VI) and NAP compared to commercial activated carbonActivated carbon is a form of carbon that has been processed to create a vast network of tiny pores, increasing its surface area significantly. This extensive surface area makes activated carbon exceptionally effective at trapping and holding impurities, like a molecular sponge. It is commonly More (CAC), suggesting MBK as a superior alternative for treating contaminated sediments. These findings highlight promising strategies for using MBK in the in-situ stabilization of Cr(VI) and NAP, offering an effective solution for mitigating environmental contamination.