Authors: Vitaly Chaban
Comments: 2 Pages.
An explosion is a quick release of a significant amount of energy from a spontaneous chemical reaction. The liberated energy is expelled in all directions, provides yellow to red flames, and forms various gases, e.g., carbon monoxide, carbon dioxide, and molecular nitrogen, containing double and triple covalent bonds. The explosion reaction, once initiated, is simultaneously driven by large exothermic and positive entropy changes.
Authors: Vitaly V. Chaban
Comments: 15 Pages.
Locating global minimum of certain atomistic ensemble is known to be a highly challenging and resource consuming task. This works represents joint usage of the semi-empirical PM7 Hamiltonian, Broyden–Fletcher–Goldfarb–Shanno algorithm and basin hopping scheme to navigate a potential energy surface. The Au20 nanocluster was used for calibration as its global minimum structure is well-known. Furthermore, Au18Ag2 and Au15Ag5 were simulated for illustration of the algorithm performance. The work shows encouraging results and, particularly, underlines proper accuracy of PM7 as applied to this type of heavy metal systems. The reported results motivate to use the benchmarked method for studying potential energy surfaces of manifold systems and locate their global-minimum atomistic configurations.
p-Nitrophenol (PNP), a widely utilized intermediate, is a persistent pollutant present in industrial effluent streams. The
inherent toxicity of PNP necessitates its treatment before releasing it in the environment. The conventional approach
pertaining to degradation of PNP is based on chemical and biological methods for decomposition. Alternatively,
Hydrodynamic Cavitation (HC) is emerging as a promising technology for waste water treatment. This study investigates
HC as an alternative technology to degrade PNP and subsequently enhance efficiency by varying involved parameters.
The HC-H2O2 system is reported to exhibit synergism for pollutant oxidation, the applicability of which is also
investigated for degrading PNP. A PNP solution of fixed concentration was subjected to HC using a circular Venturi.
Degradation was studied by varying time, pressure, pH and H2O2 concentration. Decompostion of p-Nitrophenol was
quantified by UV-Visible Spectroscopy at 405nm. Degradation of PNP was observed to be directly proportional to time
at constant pressure and an initial increase in pressure led to higher degradation. However, on achieving a peak
decomposition level, the extent of decomposition declined with further increase in pressure. Experiments done at acidic
pH resulted in over two times the decomposition than those done at basic pH. The PNP-H2O2 system exhibited 91% more
degradation than the sum of degradations affected by PNP and H2O2 individually. Moreover, subjecting PNP:H2O2 in a
molar ratio of 1:5 to HC resulted in near-complete (>95%) degradation. This study proposes variations of parameters for
optimum decomposition of PNP using HC and explores the HC-H2O2 system as a promising alternative for the