Microwave-enhanced Method Research Articles

A microwave-enhanced method able to substitute traditional pyrometallurgy for the future of metals supply from spent lithium-ion batteries

This work presents a new and promising method to recover Li, Co, Mn, and Ni from spent LIBs, based on a hybrid heating mechanism, obtained by using microwave radiation. Due to the presence of graphite, the heating is induced by the interfacial polarization of carbon atoms. The hybrid heating is based on the synergistic combination of an external susceptor with a graphite crucible. The system allows reaching carbothermic reduction conditions of black mass originating from spent LIBs, with a treatment of only a few minutes considering an electromagnetic radiation power ⋜1000 W, without any other additives. This process reduces the required associated energy by more than 2 orders of magnitude in comparison to conventional thermal treatments.The thermal process is followed by leaching in water and l-malic acid, obtaining a recovery process resulting to be competitive with metals extraction from respective ores.

Thermodynamics and kinetic studies for the microwave-enhanced extraction of phenolics from Phyllanthus niruri leaves

Phyllanthus niruri is a well-known medicinal plant with diverse pharmacological properties. This medicinal plant possesses different bioactive compounds that include phenolic compounds. In this study, the kinetics on the extraction of phenolics from P. niruri leaves using the microwave-enhanced method was examined to understand the impact of microwave power, sample-to-solvent ratio, and extraction temperature on the second-order model by varying the extraction time. Additionally, the effective diffusivity and functional groups in the leaf extract of P. niruri were determined. The outcome of this study indicated that the intensified microwave-enhanced extraction process yielded total phenolic content of 135.05 mg GAE/g extract. Moreover, the effective diffusivity ranged between 2.619 × 10−12 and 2.684 × 10−12 m2/s. The results from this study can help in predicting the estimation operation conditions for implementation in the industry. Likewise, fingerprints of the P. niruri leaf extract showed the existence of functional groups related to phenolic compounds.