Environmentally sustainable ethyl levulinate synthesis from delignified sugarcane bagasse using ternary eutectic solvent under MW-xenon irradiation: engine performance and emission assessment.

For the first time, a synergistic energy-efficient combination of microwave-xenon (MW-XE) irradiations in presence of photoactive ternary acidic deep eutectic solvents (TADES) has been applied for intensification of ethyl levulinate synthesis from delignified sugarcane bagasse (DSB) under mild (90 min, 90 °C) and environmentally benign process conditions. The Taguchi orthogonal designed optimized conditions (20 W/cm3 of MW specific irradiation power input, 1 mol/mol of FeCl3 to citric acid ratio, 90 min of reaction time, 150 W of XE specific power input) rendered maximum 61.3 mol% of EL yield (selectivity: 87.70 [Formula: see text] 0.5%). Remarkably, synergistic effect of MW and XE irradiation significantly enhanced the EL yield (61.3 mol%) compared to the individual MW (34.52 mol%) and XE (22.67 mol%) irradiation at otherwise optimized reaction conditions. Moreover, the MWXE irradiated reactor (MWXER) exhibited a significant 79.10% increase in EL yield compared to the conventional thermal reactor (CTR), at the expense of 10% less energy consumption. The ethyl levulinate could be recovered efficiently through green protocol from reaction mix resulting in high purity (97 [Formula: see text] 0.5%) and TADES was sustainably reused in the process. The optimally generated product EL when blended (5 and 10 vol.%) with B10 and B20 (10% and 20% biodiesel-diesel blend) could provide 21-31% reduction in HC and 7.3-36% reduction in CO in comparison with petro-diesel. It was also explored that, at similar optimal parametric combinations, the TADES produced 29.5% greater EL yield in comparison with the standard ionic liquid BMIMCl. The life cycle environmental impact analysis (LCEIA) of the overall process revealed that the 5 vol.% EL blending with B10 contributed lowest environmental impacts mitigating marine ecotoxicity, human toxicity, fossil depletion, and climate change by 77.9%, 77.4%, 78.4% and 77.5%, respectively.

Life cycle assessment of waste printed wiring board-derived Ag photocatalyst for sustainable fermentable sugar production.

An exploratory work involving waste printed wiring board (WPWB)-derived inexpensive silver oxide (Ag2O)-grafted silica-alumina composite photocatalyst (SAA) using quartz halogen and UVA irradiations (QHUV) (wavelength: 315 nm-1000 nm) has been revealed. The efficacy of the novel SAA photocatalyst was assessed in the synthesis of fermentable sugar (FS) by photo-hydrolysis of pure crystalline cellulose (PCC) in the QHUV-assisted batch reactor (QHUVBR), and the process parameters (5% AgNO3 doping, 7.5% catalyst concentration, 20 min PH time, and 80 °C PH temperature) were optimized using Taguchi orthogonal array design. The BET analysis of the optimal SAA catalyst possessed high surface area (27.24 m2/g), high pore volume, and pore diameter (0.042 cc/g and 13.1684 nm), respectively, whereas the XRD indicated the presence of significant crystalline phases of Ag2O. EDS mapping displayed the uniform distribution of silver active sites on silica-alumina support of the optimal SAA photocatalyst. The optimized parametric conditions in QHUVBR resulted in a maximum FS yield of 77.53% which was significantly higher compared to that achieved (34.52%) in a conventionally heated batch reactor (CHBR). Besides, the energy consumption was 75% more in CHBR (600 W) in comparison with QHUVBR (150 W), making the process energy-efficient and cost-effective. The environmental sustainability could be ascertained from the life cycle assessment (LCA) study in terms of low climate change, ionizing radiation, metal depletion, human toxicity, and other potential indicator values.

Intensified wheat husk conversion employing energy-efficient hybrid electromagnetic radiations for production of fermentable sugar: process optimization and life cycle assessment.

This article reports an energy-efficient green pathway for the sustainable conversion of an abundant agro-residue viz. wheat husk (WH) into fermentable sugar (FS). The intensification effects of tungsten-halogen (TH) (150 W) and ultraviolet (UV) (100 W) irradiations on the pretreatment and subsequent hydrolysis of WH have been experimented with and optimized by Taguchi Orthogonal Design Array (TODA). In this study, two commercial catalysts, viz. Amberlyst-15 (A15) and nano-anataseTiO2 (NAT) have been used in varying concentrations for the WH conversion process in a novel TH-UV radiated rotating reactor (THUVRR). At optimized peracetic acid pretreatment conditions [90 °C reaction temperature; 1: 2.5 w/w of WH: H2O2; 1: 5 w/w of WH: CH3COOH (1 M); 2h of reaction time] maximum 20.2 wt. % FS yield and 15 wt. % isolated lignin (purity 97.6 %) were obtained. Subsequently, the pretreated WH (PWH) was hydrolyzed at optimized conditions [(700C reaction temperature; 7.5wt. % catalyst concentration (1:1 w/w A15: NAT); 1: 30 w/w of WH: water; 30 min reaction time)] in THUVRR to render maximum yield of FS (36.9g/ L) (67.4 wt. %), which was significantly greater than that obtained (20.2g/ L) (38.42 wt. %) employing a conventional thermal reactor (CTR). Besides, the energy consumption was 70% more in CTR (500 W) in comparison with THUVRR (150 W); thus, demonstrating markedly superior energy-efficiency vis-à-vis appreciable improvement in FS yield in THUVRR over CTR. Overall sustainability of the process analyzed by LCA proved the approach to be energy-saving and environmentally benign and is expected to be applicable to similar lignocellulosic agro-wastes.