Optimization of the ionic liquid-microwave assisted one-step biodiesel production process from wet microalgal biomass

Abstract

This study illustrates the influence of ionic liquid (IL)-microwave heating on the direct transesterification (in-situ transesterification) of wet Nannochloropsis sp. biomass to biodiesel. The ionic liquid used was 1-ethyl-3-me-thylimmidazolium methyl sulphate [EMIM][MeSO4]. Direct transesterification process variables such as the wet algae to methanol ratio, reaction time and methanol to IL ratio influencing the biodiesel production were optimised using response surface methodology (RSM). The results revealed that the maximum biodiesel yield(40.9%) was achieved when the ratio of wet algae to methanol (wt/vol) was kept at 1:4, methanol :IL ratio maintained at 1:0.5 at reaction time of 25 min. The FAMEs composition depicted a high content of unsaturated FAMEs suitable for biodiesel production. The synergetic effect of combining IL-methanol solvent and microwave heating at optimised reaction conditions enabled the production of an incredibly high biodiesel yield per dry biomass of 42.22%.

A review on microalgae cultivation and harvesting, and their biomass extraction processing using ionic liquids

“…The ruptured microalgae cell releases all its intracellular contents and these contents are freely available to be extracted using ILs. Recent work conducted by Wahidin et al [85] reported that by using 1-ethyl-3-methylimmidazolium methyl sulfate as extractive solvent and combined with microwave heating, it is possible to convert directly Nannochloropsis sp. biomass to biodiesel in a single step in situ transesterification process.…”

“…biomass to biodiesel in a single step in situ transesterification process. The approach has achieved efficient biodiesel production per unit of microalgae biomass [85].…”

Ionic Liquids in Biomass Processing

“…The use of ionic liquid 1‐ethyl‐3‐methylimmidazolium methylsulfate has enabled to produce biodiesel from wet algae by direct trans‐esterification in methanol under microwave heating . The synergetic effect of combining IL – methanol solvent and microwave heating produced biodiesel in 42 % yield based on dry biomass weight . The direct conversion of wet oleaginous yeast biomass to fatty acid biodiesel using 1‐ethyl‐3‐methylimidazoliumethylsulfate and KOH is also known .…”

“…[200] The synergetic effect of combining IL -methanol solvent and microwave heating produced biodiesel in 42 % yield based on dry biomass weight. [200] The direct conversion of wet oleaginous yeast biomass to fatty acid biodiesel using 1-ethyl-3-methylimidazoliumethylsulfate and KOH is also known. [201] Some of the more recent (after 2012) applications of ILs in biodiesel synthesis are shown in Table 5.…”

Microwave‐Assisted Esterification of Oleic Acid Using an Ionic Liquid Catalyst

“…Moreover, ILs have excellent microwave absorbance because of their ionic character. Therefore, they are able to transfer energy rapidly via ionic conduction under microwave fields [25,26].…”