Adsorption of TNT and RDX Contaminants by Ambrosia trifida L. var. trifida Derived Biochar

作者：Kalyan Yakkala; Mok Ryun Yu; Jae Kyu Yang; Yoon Young Chang^*

来源：Research Journal of Chemistry and Environment, 2013, 17(4): 62-71.

• Adsorption
• biochar
• Ambrosia trifida L. var. trifida
• TNT
• RDX

Groundwater levels are often contaminated with powerful explosives 2,4,6-trinitrotoluene (TNT) and 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX) which were known to be carcinogenic and mutagenic. So far, costly physicochemical processes and time consuming methods have been applied for the removal of TNT and RDX in their binary system from wastewaters. In the present work, the adsorption of TNT and RDX from the aqueous solutions in single and binary system was investigated using the biochars (BC) derived from a waste plant, Ambrosia trifida L. var. trifida (buffalo weed) at pyrolysis temperatures of 300 degrees C, 500 degrees C and 700 degrees C as an effective adsorbent. The effects of various parameters like pH of solution, removal capacity and contact time were studied using the batch method.
It was observed that the biochar BC 700 was found to have greater removal capacity for TNT and RDX than the other developed biochars BC 300 and BC 500. The results showed that pseudo-second order kinetics provided the best parameters and the isotherm could be well described by Langmuir and Freundlich adsorption models. The maximum adsorption capacity onto the biochar BC 700, calculated from Langmuir equation was 76.923 mg g(-1) and 55.556 mg g(-1) for TNT and RDX respectively. The present adsorption process suggests that, ion exchange and chemical interactions were the main mechanisms involved. This work shows that Ambrosia trifida L. var. trifida derived biochar being a low cost material can be effectively used as an alternative adsorbent for the treatment of water and wastewater that are contaminated with explosives TNT and RDX.

• 出版日期2013-4