Translation of lignocellulosic waste to mesoporous solid acid catalyst and its efficacy in esterification of volatile fatty acid

Abstract

The growing environmental concern seeks global attention to minimize the contamination, especially for the disposal of solid wastes. In this preview, a lingocellulosic waste, de-oiled Pongamia pinnata seed cake is converted to a carbonaceous solid by incomplete carbonization and subsequent sulfonation to obtain a mesoporous solid acid catalyst. The physico-chemical properties, surface morphology and molecular structure of the different stages involved in the preparation of the solid acid catalyst was carried out through Elemental analysis, Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy, X-Ray Diffraction, Brunauer-Emmett-Teller (BET) surface area and Thermogravimetric analysis. The characterization results validate the induced catalytic property in the carbonaceous solid with pore diameter of 3.96 nm. The appropriate testification of the catalyst performance was conducted through esterification of lactic acid with n-butanol. In the experimental design based on Taguchi optimization the process parameters catalyst loading, feed molar ratio and temperature effects were investigated. The optimized results suggested a 7 wt % catalyst loading, 1:1.5 molar ratio of acid to alcohol and temperature of 115 °C for the effective conversion of volatile fatty acid. The efficacy of lignocellulosic waste catalyst was compared with other commercial catalysts; sulphuric acid, methane sulfonic acid and Amberlyst-15. Thereby, the study provides an insightful knowledge on the resourceful transformation of a non-edible solid waste precursor to an industrially applicable solid acid catalyst.