| 1. |
- Maity, Jyoti Prakash, et al.
(författare)
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Furfural removal from water by bioremediation process by indigenous Pseudomonas putida (OSBH3) and Pseudomonas aeruginosa (OSBH4) using novel suphala media : An optimization for field application
- 2023
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Ingår i: GROUNDWATER FOR SUSTAINABLE DEVELOPMENT. - : Elsevier BV. - 2352-801X. ; 20, s. 100895-
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Tidskriftsartikel (refereegranskat)abstract
- The release of furfural as effluent from industries has been considered a major pollution source since it adversely affects health and the environment. In a proper nutrient condition, the indigenous microbial removal process is always considered efficient, economical, and eco-friendly. Thus, the main objective is to employ the effective indigenous bacteria to remove the furfural from wastewater. In the present study, the indigenous isolates OSBH3 (strain number) and OSBH4 (strain number) were isolated from furfural-containing-oily-sludge and were iden-tified by 16S-rRNA technique with >99% nucleotide similarity as Pseudomonas putida (P. putida) (Acc. No. GU329915) and Pseudomonas aeruginosa (P. aeruginosa) (Acc. No. GU329916) respectively. In a batch experi-ment, the furfural degradation was observed higher in the presence of the most efficient isolate P. putida (compare to P. aeruginosa) at different nutrient conditions including Suphala (Nitrogen-Phosphorous-fertilizer), glucose, and carbohydrate-free synthetic media (CFM). Generally, the furfural degradation rate was lower in CFM than the other substrates (Nitrogen-Phosphorous-fertilizer/glucose), in the presence of P. putida or P. aeruginosa. The furfural degradation efficiency was observed higher in presence of P. putida, compare to P. aeruginosa. Experimentally, the total (100%) degradation of furfural (500 mg/L) was noticed by P. Putida within 12h incubation time in presence of 1 mg/L Suphala. Even among different factors (based on 'Taguchi L9 orthogonal array study'), the suphala (Nitrogen-Phosphorous-fertilizer) was influential in degrading the furfural at level 2, where the effects of pH and glucose were noticed at level 2 and level 2, respectively. The experimental findings supported the orthogonal array study positively. The bacterial (P. putida) growth rate and furfural degradation were promoted at the condition of 1 mg/L suphala, 2 mg/L glucose (pH 7.2), where the furfural was used by P. putida as the sole-carbon-source for growth. Thus, the indigenous P. putida (OSBH3; Acc. No. GU329915) (in presence of modified nitrogen-phosphorous-fertilizer media), can be applicable for furfural (Toxic) remediation from industrial effluent water by the eco-friendly process.
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| 2. |
- Almeida, Roseley, et al.
(författare)
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Theoretical Evidence behind Bifunctional Catalytic Activity in Pristine and Functionalized Al2C Monolayers
- 2018
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Ingår i: ChemPhysChem. - : Wiley-VCH Verlagsgesellschaft. - 1439-4235 .- 1439-7641. ; 19:1, s. 148-152
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Tidskriftsartikel (refereegranskat)abstract
- First principles electronic structure calculations based on the density functional theory (DFT) framework are performed to investigate hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) on two-dimensional Al2C monolayers. In addition to the pristine Al2C monolayer, monolayers doped with Nitrogen (N), Phosphorous (P), Boron (B), and Sulphur (S) are also investigated. After determining the individual adsorption energy of hydrogen and oxygen on the different functionalized Al2C monolayers, the adsorption free energies are predicted for each of the functionalized monolayers in order to assess their suitability for HER or OER. The density of states and optical absorption spectra calculations along with the work function of the functionalized Al2C monolayers enable us to gain a profound understanding of the electronic structure for the individual system and their relation to the water splitting mechanism.
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| 3. |
- Anversa, Jonas, et al.
(författare)
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High pressure driven superconducting critical temperature tuning in Sb2Se3 topological insulator
- 2016
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 108:21
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Tidskriftsartikel (refereegranskat)abstract
- In this letter, we are reporting the change of superconducting critical temperature in Sb2Se3 topological insulator under the influence of an external hydrostatic pressure based on first principles electronic structure calculations coupled with Migdal-Eliashberg model. Experimentally, it was shown previously that Sb2Se3 was undergoing through a transition to a superconducting phase when subjected to a compressive pressure. Our results show that the critical temperature increases up to 6.15K under the pressure unto 40GPa and, subsequently, drops down until 70 GPa. Throughout this pressure range, the system is preserving the initial Pnma symmetry without any structural transformation. Our results suggest that the possible relevant mechanism behind the superconductivity in Sb2Se3 is primarily the electron-phonon coupling.
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| 4. |
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| 5. |
- Araujo, Rafael B., et al.
(författare)
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Na2M2(SO4)(3) (M = Fe, Mn, Co and Ni) : towards high-voltage sodium battery applications
- 2016
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Ingår i: Physical Chemistry, Chemical Physics - PCCP. - : Royal Society of Chemistry (RSC). - 1463-9076 .- 1463-9084. ; 18:14, s. 9658-9665
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Tidskriftsartikel (refereegranskat)abstract
- Sodium-ion-based batteries have evolved as excellent alternatives to their lithium-ion-based counterparts due to the abundance, uniform geographical distribution and low price of Na resources. In the pursuit of sodium chemistry, recently the alluaudite framework Na2M2(SO4)(3) has been unveiled as a high-voltage sodium insertion system. In this context, the framework of density functional theory has been applied to systematically investigate the crystal structure evolution, density of states and charge transfer with sodium ions insertion, and the corresponding average redox potential, for Na2M2(SO4)(3) (M = Fe, Mn, Co and Ni). It is shown that full removal of sodium atoms from the Fe-based device is not a favorable process due to the 8% volume shrinkage. The imaginary frequencies obtained in the phonon dispersion also reflect this instability and the possible phase transition. This high volume change has not been observed in the cases of the Co- and Ni-based compounds. This is because the redox reaction assumes a different mechanism for each of the compounds investigated. For the polyanion with Fe, the removal of sodium ions induces a charge reorganization at the Fe centers. For the Mn case, the redox process induces a charge reorganization of the Mn centers with a small participation of the oxygen atoms. The Co and Ni compounds present a distinct trend with the redox reaction occurring with a strong participation of the oxygen sublattice, resulting in a very small volume change upon desodiation. Moreover, the average deintercalation potential for each of the compounds has been computed. The implications of our findings have been discussed both from the scientific perspective and in terms of technological aspects.
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| 6. |
- Araujo, Rafael B., et al.
(författare)
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Predicting electrochemical properties and ionic diffusion in Na2+2xMn2-x(SO4)(3) : crafting a promising high voltage cathode material
- 2016
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Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry. - 2050-7488 .- 2050-7496. ; 4:2, s. 451-457
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Tidskriftsartikel (refereegranskat)abstract
- Sodium ion batteries have emerged as a good alternative to lithium based systems due to their low cost of production. In this scenario, the search for higher voltage, sodium cathodes results in a new promising alluaudite structure Na2+2xMn2-x(SO4)(3). The structural, electronic and Na diffusion properties along with defects have been reported in this investigation within the framework of density functional theory. A band gap of 3.61 eV has been computed and the average deintercalation potential is determined to be 4.11 V vs. Na/Na+. A low concentration of anti-site defects is predicted due to their high formation energy. The biggest issue for the ionic diffusion in the Na2+2xMn2-x(SO4)(3) crystal structure is revealed to be the effect of Mn vacancies increasing the activation energy of Na+ ions that hop along the [001] equilibrium positions. This effect leads to activation energies of almost the same high values for the ionic hop through the [010] direction characterizing a 2D like ionic diffusion mechanism in this system.
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| 7. |
- Araujo, Rafael B., et al.
(författare)
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Unveiling the charge migration mechanism in Na2O2 : implications for sodium-air batteries
- 2015
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Ingår i: Physical Chemistry, Chemical Physics - PCCP. - : Royal Society of Chemistry (RSC). - 1463-9076 .- 1463-9084. ; 17:12, s. 8203-8209
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Tidskriftsartikel (refereegranskat)abstract
- Metal-air batteries have become promising candidates for modern energy storage due to their high theoretical energy density in comparison to other storage devices. The lower overpotential of Na compared with Li makes Na-air batteries more efficient in terms of battery lifetime. Additionally, the abundance of Na over Li is another advantage for Na batteries compared to Li batteries. Na2O2 is one of the main products of sodium-air battery reactions. The efficiency of air cells is always related to the charge transport mechanisms in the formed product. To unveil these diffusion mechanisms in one of the main products of the cell reaction Na-O-2 we systematically investigate the mobility of charge carriers as well as the electronic structural properties of sodium peroxide. The framework of the density functional theory based on hybrid functional approach is used to study the mobility of charge carriers and intrinsic defects in Na2O2. Our calculations reveal that the formation of small electron and hole polarons is preferentially occurring over the delocalized state in the crystal structure of Na2O2. The migration of these small polarons displays activation energies of about 0.92 eV and 0.32 eV for the electron and hole polarons respectively, while the analysis of the charged sodium vacancy mobility reveals an activation energy of about 0.5 eV. These results suggest that the charge transport in sodium peroxide would mainly occur through the diffusion of hole polarons.
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| 8. |
- Banerjee, Amitava, et al.
(författare)
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Bromination-induced stability enhancement with a multivalley optical response signature in guanidinium [C(NH2)(3)](+)-based hybrid perovskite solar cells
- 2017
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Ingår i: Journal of Materials Chemistry A. - : ROYAL SOC CHEMISTRY. - 2050-7488 .- 2050-7496. ; 5:35, s. 18561-18568
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Tidskriftsartikel (refereegranskat)abstract
- Guanidinium lead iodide (GAPbI(3)) has been synthesized experimentally, but stability remains an issue, which can be modulated by the insertion of bromine (Br) into the system. We have performed a systematic theoretical investigation to see how bromination can tune the stability of GAPbI(3). The optical properties were also determined, and we have found formation enthalpy-based stability in the perovskite systems, which are active in the visible and IR region even after bromine insertion and additionally more active in the IR range with the transition from GAPbI(3) to GAPbBr(3). The spin orbit coupling effect is considered throughout the band structure calculations. The ensemble of the primary and secondary gaps in the half and fully brominated hybrid perovskites leads to the phenomenon of a multipeak response in the optical spectra, which can be subsequently attributed as multivalley optical response behaviour. This multivalley optical behaviour enables the brominated guanidinium-based hybrid perovskites to exhibit broad light harvesting abilities, and this can be perceived as an idea for natural multi-junction solar cells.
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| 9. |
- Banerjee, Amitava
(författare)
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Materials Modelling for Energy Harvesting : From Conversion to Application through Storage
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In this Ph.D. thesis, ab initio density functional theory along with molecular dynamics and global optimization methods are used to unveil and understand the structures and properties of energy relevant materials. In this connection, the following applications are considered: i. electrocatalyst for solar fuel production through water splitting, ii. hybrid perovskite solar cell for generation of electrical energy and iii. Battery materials to store the electrical energy. The water splitting mechanism in terms of hydrogen evolution and oxygen evolution reactions (HER and OER) on the catalytic surfaces has been envisaged based on the free energy diagram, named reaction coordinate, of the reaction intermediates. The Ti-functionalized two-dimensional (2D) borophene monolayer has been emerged as a promising material for HER and OER mechanisms as compared to the pristine borophene sheet. Further investigation in the series of this noble metal free monolayer catalyst is 2D Al2C monolayer both in form of pristine and functionalized with nitrogen (N), phosphorous (P), boron (B), and sulphur (S). It has been observed that only B substituted Al2C shows very close to thermoneutral, that could be the most promising candidate for HER on functionalized Al2C monolayer. The adsorption of O* intermediate is stronger in S-substituted Al2C, whereas it is less strongly adsorbed on N-substituted Al2C. The subsequent consideration is being the case of n-type doping (W) along with Ti codoped in BiVO4 to enhance the efficiency of BiVO4 photoanode for water splitting. The determined adsorption energy and corresponding Gibbs free energies depict that the Ti site is energetically more favorable for water splitting. Moreover, the Ti site possesses a lower overpotential in the W–Ti codoped sample as compared to the mono-W doped sample. We have also explored the effect of mixed cation and mixed anion substitution in the hybrid perovskite in terms of structural stability, electronic properties and optical response of hybrid perovskite crystal structures. It has been found that the insertion of bromine (Br) into the system could modulate the stability of the Guanidinium lead iodide (GAPbI3) hybrid perovskite. Moreover, the band gap of the mixed hybrid perovskite is increased with the inclusion of smaller Br anion while replacing partially the larger iodine (I) anion. Finally the electrochemical storage mechanism for Sodium (Na) and lithium (Li) ion insertion has been envisaged in inorganic electrode (eldfellite, NaFe(SO4)2) as well as in more sustainable organic electrode (di-lithium terephthalate, Li2TP). The full desodiation capability of the eldfellite enhances the capacity while the activation energies (higher than 1 eV) for the Na+ ion diffusion for the charged state lower the ionic insertion rate. The key factor as the variation of Li-O coordination in the terephthalate, for the disproportionation redox reaction in Li2TP is also identified.
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| 10. |
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