Solubility of pyridine-2,6-dicarboxylic acid in supercritical carbon dioxide and its application for removal of lead and nickel in simulated matrices

The solubility of pyridine-2,6-dicarboxylic acid in supercritical carbon dioxide was measured at 313-333 K and 10-20 MPa, using a flow-saturation technique. The influence of methanol on solubility behavior is investigated. The solubility in neat supercritical carbon dioxide ranged from 0.44 x 10-6 mol center dot moltot-1 to 3.4 x 10-6 mol center dot moltot-1 ,while its solubility in presence of methanol ranged from 0.17 x 10-5 mol center dot moltot-1 to 18.1 x 10-5 mol center dot moltot-1. The solubility data was modeled with Chrastil, Mendez-Teja, Garlapati equations and Peng-Robinson equation of state model. The solubility in the presence of methanol was correlated using modified Chrastil, modified Mendez-Teja and Thakur models. Among the models employed, Chrastil model (binary system) and modified Mendez-Teja model (ternary system) shown highest accordance with experimental data. Pyridine-2,6-dicarboxylic acid was employed as a chelating agent for development of a supercritical fluid extraction method for removal of Pb2+ and Ni2+ from simulated aqueous/soil matrices.

Automated summary

The solubility of pyridine-2,6-dicarboxylic acid in supercritical carbon dioxide was measured at different temperatures and pressures, with and without methanol. The solubility data was modeled using various equations, with the Chrastil and Mendez-Teja models showing the best agreement with experimental results. Pyridine-2,6-dicarboxylic acid was used as a chelating agent for developing a supercritical fluid extraction method for removing Pb2+ and Ni2+ from aqueous/soil matrices.