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![Comparison of various pretreatment methods [20].](publication/334559392/figure/tbl1/AS:939285700157440@1600954570186/Comparison-of-various-pretreatment-methods-20.png)
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![Fig. 1: Loosening of structure on pretreatment [5].](publication/334559392/figure/fig1/AS:939285700165632@1600954570123/Loosening-of-structure-on-pretreatment-5_Q320.jpg)
![Comparison of various pretreatment methods [20].](publication/334559392/figure/tbl1/AS:939285700157440@1600954570186/Comparison-of-various-pretreatment-methods-20_Q320.jpg)
A lot of recent research in the biomass sector is focusing on how to improve the efficiency of biomass resources. Pretreatment of biomass resources is a novel approach and has gained a lot of attention in the last decade. A review of modern methods and latest technologies of enhancing the enzymatic saccharification of sugarcane bagasse are presente...
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... of ammonia and the ionic liquid was employed for pretreatment of rice straw [19] and switch grass [20]. Li et al. compared untreated, dilute acid treated and ionic liquid treated biomass based on crystallinity index, rate enhancement, and digestibility (see Table 2). Woody biomass has also been subjected to ionic liquid pretreatment [21][22][23]. ...Citations
... (Naqvi et al., 2016;Farooq et al., 2017;Shehzad et al., 2016;Mirani et al., 2013;Maitlo et al., 2019;Mahmood et al., 2019;Naqvi et al., 2020;Iqbal et al., 2019;Kim et al., 2020; Shah et all., 2019;Fatma et al., 2018;Haq et al., 2020;Saboor et al., 2017;Saeed & Saleem, 2018; Bhutto et al., 2016;Asim et al., 2019;Raychaudhuri & Ghosh, 2015;Naseem et al., 2019;Rezania et al., 2019;Shafiq et al., 2020). ...
Though frequent availability of energy is vital for economic growth, using any energy source can have a certain degree of impact on the environment. Pakistan is facing the worst power crisis nowadays. The government of Pakistan has been focused to find energy solutions in fossil fuels. As the world moves towards a clean sustainable direction, coal sources, are cheap at the moment, and new coal-based power plants can be put up quickly with a predictable output, but with the degradation of the environment, Pakistan can utilize sustainable energy resources such as biomass, solar energy, hydropower, and wind power; which are frequently available in Pakistan and can generate environment-friendly power above 40,000 MW. It is necessary to consider these sustainable energy resources, as their prices have been dipping dramatically and it is now cheaper to build new commercial plants based on improved technologies able to generate more electricity. The present paper discusses the insight environment-friendly sustainable energy options available in Pakistan other than coal-fired plants to overcome future energy demand.
... Pretreatment is a vital step to make SCB a feasible and sustainable energy resource. Cost, capacity, structural fragmentation, energy consumption, and product formation are the essential factors in choosing a suitable pretreatment method [5]. The scientific community is moving away from conventional pretreatment agents like acids and alkalis due to high energy consumption, formation of inhibiting by-products, high volatility, and corrosiveness. ...
This work investigated the pretreatment effect of four ionic liquids (ILs) on sugarcane bagasse (SCB) through reactivity, kinetic, and thermodynamic analysis. The ILs used in this study were 1-butyl-3-methylimidazolium chloride ([Bmim][Cl]), 1-butyl-3-methylimidazolium methylsulfate ([Bmim][MeSO4]), Tris (2-hydroxyethyl) methylammonium methylsulfate ([MTEOA][MeSO4]), and trihexyltetradecylphosphonium chloride ([P66614] [Cl]). Pretreatment was carried out at 150 °C and 30 min, followed by thermal analysis of samples in a thermogravimetric analyzer (TGA). The activity parameters were obtained using TGA data. [P66614] [Cl] was completely absorbed in SCB, which strongly influenced the thermochemical behavior of [P66614] [Cl] treated sample. Results revealed that IL pretreatment greatly reduced ash content and increased the higher heating value (HHV) of SCB. Chemical composition analysis showed delignification of SCB by [Bmim][Cl], [Bmim][MeSO4] and [MTEOA][MeSO4]. However, [P66614] [Cl] increased lignin content indicating thermal stability. The obtained values of activation energy (Ea) for [Bmim][Cl], [Bmim][MeSO4], and [MTEOA][MeSO4] were much lower than that for untreated SCB, suggesting destruction of the lignocellulosic structure. Higher entropy change (ΔS) values after IL treatment implied higher disorder due to the breakage of SCB structure. The study demonstrated that the nature of cations and anions strongly influences the pretreatment potential of ILs for biomass undergoing thermochemical conversion processes.
Currently, society is looking for new alternative energy sources, cleaner and less harmful to the environment, and an example of this is the depletion of fossil fuels and the search for biofuels from various renewable materials, which can be classified as first and second generation. The most common in the industry is the first-generation biofuel obtained through edible oils or vegetable sugars, mainly corn and sugar calla, and the second-generation biofuel obtained from the exploitation of residual raw material residues from food industries, forest residues among others. On the other hand, the third-generation biofuels are obtained from non-food species by using molecular biology techniques in which microalgae currently stand out, and finally, in a similar way, the fourth-generation biofuels are manufactured from non-arable land. However, unlike third-generation biofuels, it does not require the destruction of biomass. The relationship between the different types of biofuels is the search for the saccharification process, which is a process in which a polysaccharide is transformed into fermentable sugar. Enzymatic hydrolysis is a type of saccharification in which the process is catalyzed by a group of enzymes generically called cellulases, which are a mixture of different enzymatic activities whose combined action degrades cellulose. During enzymatic hydrolysis, cellulose is degraded by cellulases to reducing sugars that can be fermented by yeast or bacteria to ethanol. This chapter will address the recent developments in the enzymatic saccharification (ES) technologies for biofuel production in their current state, challenges, products in the market, and prospects.
Cellulosic ethanol, considered as one of the advanced biofuels, is produced from the abundantly available plant-origin lignocellulosic biomass (LCB). Optimal recovery of fermentable sugars from cellulose and hemicellulose constituents of LCB is still considered a major bottleneck to the cost-effective commercial production of cellulosic ethanol. Sugars are recovered from LCB by employing a variety of lignocellulolytic enzymes (LCE), including cellulases, hemicellulases, and accessory enzymes. In recent past, much effort has been put in development of robust LCEs and decreasing their production cost, advancements in fermentation technology for LCE production, and development of more efficient in-house enzyme cocktails to replace the commercial enzymes. Therefore, this chapter provides background knowledge on LCEs, some challenging aspects and recent progress in cellulolytic enzyme production and applications for cellulosic ethanol production, with special emphasis on advancements in commercialization of LCEs.
This paper aims to investigate the thermochemical behavior and synergistic effects of low-rank coal, and sugarcane bagasse (SCB) blends after pretreatment by trihexyltetradecylphosphonium chloride ([P66614] [Cl]). Three samples of coal and SCB blends, C75B25, C50B50, and C25B75, in ratios 3:1, 1:1, and 1:3 by weight, respectively, were prepared and pretreated with [P66614] [Cl] at 150 °C for 3 h. Hereafter, they were subjected to thermogravimetric analysis (TGA) under an inert atmosphere at a fixed heating rate of 20 °C. Thermal performance and synergistic effects were evaluated and compared by reactivity, kinetic, and thermodynamic analysis. Ten different models related to four reaction mechanisms were applied to evaluate kinetic and thermodynamic parameters. During pretreatment, [P66614] [Cl] was completely absorbed in blends and individual fuels. TGA results showed that IL treatment altered the thermal profiles of the blends at 350–500 °C. [P66614] [Cl] treatment caused an increase in total weight loss of 7.15%, 2.81%, and 1.62% for C75B25, C50B50, and C25B75, respectively. Peak temperatures for C75B25, C50B50, and C25B75 changed from 356, 365, and 374 °C to 472, 459, and 485 °C, respectively, after IL treatment, indicating thermal stability. The relative mean reactivity (Rm) for C75B25 increased (8.78 to 14.94%min⁻¹°C⁻¹), whereas for C50B50 and C25B75 (16.1 and 20.15%min⁻¹°C⁻¹ to 14.84 and 13.61%min⁻¹°C⁻¹) decreased after [P66614] [Cl] treatment, implying synergistic effects. Among the reaction models, R² values in excess of 0.80 were obtained for all the samples, with activation energy of C75B25, C50B50, C25B75, C75B25 + [P66614] [Cl], C50B50 + [P66614] [Cl], and C25B75 + [P66614] [Cl] in the range of 12.48–51.17 kJ/mol, 12.53–46.07 kJ/mol, 10.85–45.40 kJ/mol, 8.11–35.50 kJ/mol, 6.9–33.59 kJ/mol, 6.65–41.32 kJ/mol, respectively. Entropy values suggested increased depolymerization of fuel structure due to IL treatment. Low synergy was detected in untreated as compared to IL treated blends. [P66614] [Cl] treatment seemed to have a more significant effect on samples having higher carbon content as compared to SCB. This study could be useful in modeling and designing co-thermochemical conversion processes for coal and SCB blends after low-cost [P66614] [Cl] pretreatment.
This paper aims to investigate the impact of ionic liquid (ILs) pretreatment on low-grade coal for the thermochemical conversion process. Two imidazolium-based ILs, 1-butyl-3-methylimidazolium chloride [Bmim][Cl], and 1-ethyl-3-methylimidazolium chloride [Emim][Cl]; one ammonium-based IL, tributylmethylammonium chloride [N1444] [Cl]; and one phosphonium-based IL trihexyltetradecylphosphonium chloride [P66614] [Cl], were selected for this study. Reactivity, kinetic, and thermodynamic parameters were calculated via thermogravimetric analysis (TGA) conducted under N2 environment at a ramp rate of 20 °C/min. All four ILs increased the higher heating value (HHV) of coal. The IL treatment resulted in greater mass loss and enhanced reactivity of coal. The highest reactivity of 11.45%min⁻¹°C⁻¹ and pyrolysis factor (PF) of 23.28, nearly four and six times, respectively, higher than that of raw coal, were recorded for the [P66614] [Cl] treated sample. This could be attributed to the complete absorption of [P66614] [Cl] in coal and its high hydrogen bond basicity (HBB). Activation energies and pre-exponential factors were calculated using the model-fitting analysis with regression coefficient R² in the range of 0.979–0.999. All ILs, except [P66614] [Cl], reduced the activation energy of coal, indicating degradation of coal structure. The higher activation energy in the case of [P66614] [Cl] suggests increase in thermal stability of coal. The results indicate that relatively low-cost phosphonium and ammonium-based ILs can be potential pretreatment agents for coal thermochemical conversion processes.
