Emerging lignocellulosic ionic liquid biomass pretreatment criteria/strategy of optimization and recycling short review with infrared spectroscopy analytical know-how

Abstract

• Pretreatment of lignocellulosic biomass (LCB) using ionic liquid solvent review in general. • Pretreatment optimization with recycling technique on LCB review information. • Fourier Transform Infrared Spectroscopy (FTIR) shift and change of FTIR peaks/curve prediction/relationship comparing the untreated to the pretreated lignocellulosic biomass sample of oil palm source of oil palm frond (OPF), empty fruit bunch (EFB), oil palm trunk (OPT) and micro crystalline (MCC) biomass analytical area under the curve data. Pretreatment of various types of lignocellulosic biomass (LCB) being shortly reviewed as criteria concerning emerging pretreatment solvents, recycling strategies and optimization. Review findings presented include pretreatment methods, recycling techniques, ionic liquid types, optimization parameters (dependent/independent), optimization model and references. In this article, original investigated research Fourier Transform Infrared Spectroscopy (FTIR) pretreatment data on oil palm frond (OPF), empty fruit bunch (EFB), oil palm trunk (OPT) and microcrystalline cellulose (MCC) were also presented, aiding the indirect indicator strategy of the effect of pretreatment via FTIR analysis to support the criteria analysis. The strategy covers certain spectroscopy changes when 1-ethyl-3-methylimidazolium acetate [EMIM]Ac and electron beam irradiation (EBI) pretreatments on untreated and treated LCB samples, predicting shift in peaks or change of shape of the FTIR curve at specific wavenumber spectral region. Fundamentally, the obvious decrease of area under the curve values relationship with the pretreatment effects for three (3) spectroscopy FTIR functional groups representing stretching and vibration of oxygen, hydrogen and carbon combinations within the range of 3125 to 3600, 2850 to 2950 and 890 to 1200 cm −1 on four (4) different microcrystalline cellulose conditions of being untreated together with ionic liquid pretreatments of 50% (v/v) and 100% (v/v) [EMIM]Ac and finally with radiation pretreatment of 1000 kGy EBI conditions, can be useful for the criteria analytical understanding spectroscopically.