Ultralow Sulfur Diesel and Rapeseed Methyl Ester Fuel Impact on Performance, Emitted Regulated, Unregulated, and Nanoparticle Pollutants

Copyright © 2022 The Authors. The operation of engines using rapeseed methyl ester (RME) and ultralow sulfur diesel (ULSD) was tested for the combustion properties, emitted regulated, unregulated exhaust pollutants, and the size of nanoparticles. The combustion analysis showed higher apparent heat release rate and shorter ignition delay period during RME combustion than during ULSD combustion. The ULSD engine has a combustion chamber maximum pressure relatively higher than that of RME. This study showed that the heat release rate of ULSD is always higher than that of RME while more fuel consumption occurred from the combustion of biodiesel in comparison with diesel. When the engine is running on RME, HC and NOx formation increased at high loads up to 15% and 13%, respectively; meanwhile, CO concentrations reduced by 30.9% for the same conditions. Most of the particulate matter (PM) emitted from a diesel engine has a particle size from 5 to 100 nm, while the particle size from ULSD ranged from 5 to 40 nm. Overloading the engine caused a decrease in the sizes of emitted PM for both fuels. The smoke number for RME was less than that for ULSD by 33.9% at high loads. For high engine load, the cumulative concentration number for the nucleation mode decreased, while it increased for the accumulation mode. Furthermore, measurements of formaldehyde, ethane, methane, acetylene, ethylene, propylene, and isocyanic acid emissions showed the presence of these harmful substances at very low concentrations (8 ppm) for both fuels

Enhanced photoelectrochemical performance of Z-scheme g-C3N4/BiVO4 photocatalyst

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.BiVO 4 is a considerably promising semiconductor for photoelectrochemical water splitting due to its stability, low cost and moderate band gap. In this research, g-C 3 N 4 was proposed in Z-scheme configuration which boosted the performance of BiVO 4 up to four times. The experimental observations were counterchecked with Density Functional Theory (DFT) simulations. A TiO 2 /BiVO 4 heterojunction was developed and its performance was compared with that of g-C 3 N 4 /BiVO 4 . The photocurrent for g-C 3 N 4 /BiVO 4 was 0.42 mAcm −2 at 1.23 V vs. RHE which was the highest among g-C 3 N 4 based Z-scheme heterojunction devices. Lower charge transfer resistance, higher light absorption and more oxygen vacancy sites were observed for the g-C 3 N 4 based heterojunction. The simulated results attested that g-C 3 N 4 and BiVO 4 formed a van der Waals type heterojunction, where an internal electric field facilitated the separation of electron/hole pair at g-C 3 N 4 /BiVO 4 interface which further restrained the carrier recombination. Both the va lence and conduction band edge positions of g-C 3 N 4 and BiVO 4 changed with the Fermi energy level. The resulted heterojunction had small effective masses of electrons (0.01 m e ) and holes (0.10 m e ) with ideal band edge positions where both CBM and VBM were well above and below the redox potential of water.The authors would like to acknowledge financial support from Universiti Kebangsaan Malaysia through internal grant GUP-2016-089 and also for providing facilities to perform this research. H.U. acknowledges the supercomputing facilities of ESI Beowulf Cluster, University of Exeter, UK

Activated carbon-supported CuO nanoparticles: a hybrid material for carbon dioxide adsorption

Activated carbon-supported copper(II) oxide (CuO) nanoparticles were synthesized by simple impregnation method to improve carbon dioxide (CO2) adsorption capacity of the support. The structural and chemical properties of the hybrid material were characterized by scanning electron microscopy (SEM), energy dispersive X-ray (EDX), X-ray diffraction (XRD), Xray photoelectron spectroscopy (XPS), atomic absorption spectroscopy (AAS), and Brunauer-Emmett-Teller (BET) analyses. The analyses showed that CuO nanoparticles are well-distributed on the activated carbon surface. The CO2 adsorption behavior of the activated carbon-supported CuO nanoparticles was observed by thermogravimetric analysis (TGA), temperature programmed desorption (TPD), Fourier transform infrared (FTIR), and BETanalyses. The results showed that CuO nanoparticle loading on activated carbon led to about 70 % increase in CO2 adsorption capacity of activated carbon under standard conditions (1 atm and 298 K). The main contributor to the observed increase is an improvement in chemical adsorption of CO2 due to the presence of CuO nanoparticles on activated carbon