Response Surface Methodological Approach to Optimize Microwave-assisted Extraction of Cayirhan Lignite

Abstract

Microwave-assisted extraction of Cayirhan lignite was investigated using N-methyl-2-pyrrolidinone. The response surface methodology was employed to optimize the microwave-assisted extraction conditions. The controllable factors selected in the present investigation included the extraction temperature, extraction time, and solvent-to-coal ratio. The obtained results demonstrated that the extraction temperature was the most important factor, which had a positive influence on the extraction yield. The statistical model predicted that a higher extraction yield of up to 28% would be obtained at the following optimized conditions: an extraction temperature between 217–230°C, a solvent-to-coal ratio of 13.5, and an extraction time of 28–30 min.

Keywords:

• coal
• microwave-assisted extraction
• N-methyl-2-pyrrolidinone
• optimization
• response surface methodology

Additional information

Funding

This work was supported by the Mersin University Research Fund (Contract no: BAB-FEF KB (OS) 2010-4A) and TUBITAK (Scientific and Technical Research Council of Turkey, Project Reference 111M145).