• Energy Research

Recent developments in biogas upgradation have opened new horizons for its utilisation because upgradation technologies are fully developed and commercially available. However, the implementation of biogas upgrading technologies is not at the scale required to harness the full potential of biogas. Therefore, it is requisite to adopt a multicriteria decision-making methodology (MCDM) to select the most appropriate biogas up-gradation technology as each technology has its own set of benefits and downside. In this multifaceted scenario, the analytical hierarchy Process (AHP), one of the most preferred MCDM methods in rational decision-making, is applied in this study to select the most appropriate biogas upgrading technology. The broader recognition of AHP is its provision for converting multifaceted problems into a simple hierarchy. The research results reveal that biogas up-gradation technologies based on water scrubbing and membrane separation rank first and second among the alternatives. This research will show a direction to researchers and the MCDM community involved in biogas upgradation technologies on a broader scale.

Recent developments in biogas upgradation have opened new horizons for its utilisation because upgradation technologies are fully developed and commercially available. However, the implementation of biogas upgrading technologies is not at the scale required to harness the full potential of biogas. Therefore, it is requisite to adopt a multicriteria decision-making methodology (MCDM) to select the most appropriate biogas up-gradation technology as each technology has its own set of benefits and downside. In this multifaceted scenario, the analytical hierarchy Process (AHP), one of the most preferred MCDM methods in rational decision-making, is applied in this study to select the most appropriate biogas upgrading technology. The broader recognition of AHP is its provision for converting multifaceted problems into a simple hierarchy. The research results reveal that biogas up-gradation technologies based on water scrubbing and membrane separation rank first and second among the alternatives. This research will show a direction to researchers and the MCDM community involved in biogas upgradation technologies on a broader scale.

The prospective utilization of bael shell (Aegle marmelos) as an agro-waste for the production of biochar was investigated along with its characterization and application for the abatement of hazardous aqueous Patent Blue (PB) dye solution. The sorptive removal of PB on bael shell biochar (BSB) was investigated under the following operational conditions: (pH, 2.7–10.4; biochar dosage, 2–12 g/L; and contact time, 0–60 min). The removal efficiency of PB by BSB in a batch adsorption experiment was 74% (pH 2.7 and 30 ± 5 °C). In addition, a clear relationship between the adsorption and pH of the solution was noticed and the proposed material recorded a maximum sorption capacity of 3.7 mg/g at a pH of 2.7. The adsorption of PB onto BSB was best explained by the pseudo-second order kinetic model (R2 = 0.972), thereby asserting the predominant role of chemisorption. The active role of multiple surface-active functionalities present on BSB during PB sorption was elucidated with the help of Freundlich isotherm (R2 = 0.968). Further, an adsorption mechanism was proposed by utilizing Fourier transform infrared spectroscopy (FTIR).

The prospective utilization of bael shell (Aegle marmelos) as an agro-waste for the production of biochar was investigated along with its characterization and application for the abatement of hazardous aqueous Patent Blue (PB) dye solution. The sorptive removal of PB on bael shell biochar (BSB) was investigated under the following operational conditions: (pH, 2.7–10.4; biochar dosage, 2–12 g/L; and contact time, 0–60 min). The removal efficiency of PB by BSB in a batch adsorption experiment was 74% (pH 2.7 and 30 ± 5 °C). In addition, a clear relationship between the adsorption and pH of the solution was noticed and the proposed material recorded a maximum sorption capacity of 3.7 mg/g at a pH of 2.7. The adsorption of PB onto BSB was best explained by the pseudo-second order kinetic model (R2 = 0.972), thereby asserting the predominant role of chemisorption. The active role of multiple surface-active functionalities present on BSB during PB sorption was elucidated with the help of Freundlich isotherm (R2 = 0.968). Further, an adsorption mechanism was proposed by utilizing Fourier transform infrared spectroscopy (FTIR).

Abstract In the present study, hybrid bio-support catalyst (BSC) has been prepared for the production of biodiesel from Castor oil. Lipase from Pseudomonas cepacia has been immobilized on a hybrid bio-support material (BSM) by entrapment method and characterized. The highest immobilized lipase activity and loading efficiency were 87.28 (U/g) and 55.2%, respectively. The composition of Castor oil expelled from Castor seeds evaluated through Gas Chromatograph-Mass Spectrometer (GC-MS) technique. GCMS spectra show the percentage composition of ricinoleic, linoleic, oleic, stearic, palmitic, and nonanoic acid, as 78.67, 9.62, 6.65, 1.53, 2.19, and 0.08, respectively. Optimized conditions for the transesterification of Castor oil with propan-2-ol as acyl acceptor in solvent free medium were, 10% immobilized lipase relying on oil-weight, molar ratio of alcohol to oil (6:1) at 50 ± 1 °C for the period of 24 h. The product yield was estimated as 75% while the calculated conversion of biodiesel was approximately 78%. The reusability of hybrid BSC for 12 runs was found to be 70% of its initial biodiesel yield after 6 cycles. The properties of oil and biodiesel were calculated using American Standards for Testing Material (ASTM) D6751; formation of biodiesel confirmed by Proton Nuclear Magnetic Resonance (1H NMR) and Fourier Transform Infrared (FTIR) analysis.

Abstract In the present study, hybrid bio-support catalyst (BSC) has been prepared for the production of biodiesel from Castor oil. Lipase from Pseudomonas cepacia has been immobilized on a hybrid bio-support material (BSM) by entrapment method and characterized. The highest immobilized lipase activity and loading efficiency were 87.28 (U/g) and 55.2%, respectively. The composition of Castor oil expelled from Castor seeds evaluated through Gas Chromatograph-Mass Spectrometer (GC-MS) technique. GCMS spectra show the percentage composition of ricinoleic, linoleic, oleic, stearic, palmitic, and nonanoic acid, as 78.67, 9.62, 6.65, 1.53, 2.19, and 0.08, respectively. Optimized conditions for the transesterification of Castor oil with propan-2-ol as acyl acceptor in solvent free medium were, 10% immobilized lipase relying on oil-weight, molar ratio of alcohol to oil (6:1) at 50 ± 1 °C for the period of 24 h. The product yield was estimated as 75% while the calculated conversion of biodiesel was approximately 78%. The reusability of hybrid BSC for 12 runs was found to be 70% of its initial biodiesel yield after 6 cycles. The properties of oil and biodiesel were calculated using American Standards for Testing Material (ASTM) D6751; formation of biodiesel confirmed by Proton Nuclear Magnetic Resonance (1H NMR) and Fourier Transform Infrared (FTIR) analysis.

Microbial fuel cells (MFCs) are an emerging technology for converting organic waste into electricity, thus providing potential solution to energy crises along with eco-friendly wastewater treatment. The electrode properties and biocatalysts are the major factors affecting electricity production in MFC. The electrons generated during microbial metabolism are captured by the anode and transferred towards the cathode via an external circuit, causing the flow of electricity. This flow of electrons is greatly influenced by the electrode properties and thus, much effort has been made towards electrode modification to improve the MFC performance. Different semiconductors, nanostructured metal oxides and their composite materials have been used to modify the anode as they possess high specific surface area, good biocompatibility, chemical stability and conductive properties. The cathode materials have also been modified using metals like platinum and nano-composites for increasing the redox potential, electrical conductivity and surface area. Therefore, this paper reviews the recent developments in the modification of electrodes towards improving the power generation capacity of MFCs.

Microbial fuel cells (MFCs) are an emerging technology for converting organic waste into electricity, thus providing potential solution to energy crises along with eco-friendly wastewater treatment. The electrode properties and biocatalysts are the major factors affecting electricity production in MFC. The electrons generated during microbial metabolism are captured by the anode and transferred towards the cathode via an external circuit, causing the flow of electricity. This flow of electrons is greatly influenced by the electrode properties and thus, much effort has been made towards electrode modification to improve the MFC performance. Different semiconductors, nanostructured metal oxides and their composite materials have been used to modify the anode as they possess high specific surface area, good biocompatibility, chemical stability and conductive properties. The cathode materials have also been modified using metals like platinum and nano-composites for increasing the redox potential, electrical conductivity and surface area. Therefore, this paper reviews the recent developments in the modification of electrodes towards improving the power generation capacity of MFCs.