8 research outputs found
Evaluation of Hospital Wastewater Treatment Using Sewage Treatment Plant for Heavy Metals, Radionuclides, and Some Pharmaceuticals: A Case Study
No full textThis is the first study in Oman to evaluate the efficiency of a sewage treatment plant (STP) for hospital wastewater (HWW) treatment for heavy metals, radionuclides, and some selected pharmaceuticals. A sewage treatment plant (STP) at Sultan Qaboos University (SQU) receives HWW, from Sultan Qaboos University Hospital (SQUH), and municipal wastewater from non-medical facilities at SQU. Representative samples of HWW (before mixing with municipal wastewater at STP), STP-treated wastewater (TWW), and STP mixing sludge, were collected and analyzed. A method for analyzing pharmaceuticals including metformin, atenolol, chlorpheniramine, triprolidine, diphenhydramine, and citalopram was developed and validated using LC-MS-MS. HWW and TWW show low concentrations of heavy metals. Radionuclides found in HWW include Cs137, K40, Ra226, Th234, I131, Tl208, Zn65 Ac228, Sb125, Bi124 and Be7. Diphenhydramine (2.24 mg/L), chlorpheniramine (0.293 mg/L) and atenolol (0.0260 mg/L) were found in HWW. Heavy metals, radionuclides, and pharmaceuticals were found less in TWW than in HWW. STP sewage sludge showed higher levels of these pollutants than HWW or TWW. Concentrations of diphenhydramine, chlorpheniramine, and citalopram were 137, 0.950, and 169 mg/kg, respectively in dried sewage sludge. The study confirms the ineffectiveness of STP treatment to completely remediate HWW. HWW should be considered hazardous and requires physico-chemical treatment before mixing with municipal wastewater.
Keywords: Hospital, pharmaceuticals, radionuclides, heavy metals, wastewater
The effect of Zn substitution on the structure and magnetic properties of magnesium nickel ferrite
No full textMössbauer Study of Weathered H-meteorite from the Desert of Oman
No full textA number of meteorites from the desert of Oman, classified as H-chondrites, with known and unknown ages, were studied by using 57Fe Mössbauer spectroscopy to determine their Fe3+-bearing compositions. Mössbauer spectra measured at 78 K were composed of paramagnetic doublets superimposed on magnetic sextets. The doublets are assigned to the silicate minerals olivine and pyroxene and Fe3+ phases. The magnetic sextets in most samples showed the presence of at least three magnetic phases, namely troilite, magnetite and kamacite, which commonly exist in most ordinary chondrites. The relative amounts (area %) of Fe3+ in the known-age meteorites, determined from the Mössbauer spectra, were plotted against their terrestrial ages. The plot was used to estimate the terrestrial ages of meteorites with unknown terrestrial age
Maghemite (γ-Fe2O3) and γ-Fe2O3-TiO2 Nanoparticles for Magnetic Hyperthermia Applications: Synthesis, Characterization and Heating Efficiency
No full textIn this report, the heating efficiencies of γ-Fe2O3 and hybrid γ-Fe2O3-TiO2 nanoparticles NPs under an alternating magnetic field (AMF) have been investigated to evaluate their feasible use in magnetic hyperthermia. The NPs were synthesized by a modified sol-gel method and characterized by different techniques. X-ray diffraction (XRD), Mössbauer spectroscopy and electron microscopy analyses confirmed the maghemite (γ-Fe2O3) phase, crystallinity, good uniformity and 10 nm core sizes of the as-synthesized composites. SQUID hysteresis loops showed a non-negligible coercive field and remanence suggesting the ferromagnetic behavior of the particles. Heating efficiency measurements showed that both samples display high heating potentials and reached magnetic hyperthermia (42 °C) in relatively short times with shorter time (~3 min) observed for γ-Fe2O3 compared to γ-Fe2O3-TiO2. The specific absorption rate (SAR) values calculated for γ-Fe2O3 (up to 90 W/g) are higher than that for γ-Fe2O3-TiO2 (~40 W/g), confirming better heating efficiency for γ-Fe2O3 NPs. The intrinsic loss power (ILP) values of 1.57 nHm2/kg and 0.64 nHm2/kg obtained for both nanocomposites are in the range reported for commercial ferrofluids (0.2–3.1 nHm2/kg). Finally, the heating mechanism responsible for NP heat dissipation is explained concluding that both Neel and Brownian relaxations are contributing to heat production. Overall, the obtained high heating efficiencies suggest that the fabricated nanocomposites hold a great potential to be utilized in a wide spectrum of applications, particularly in magnetic photothermal hyperthermia treatments
Investigating Exchange Bias and Coercivity in Fe3O4–γ-Fe2O3 Core–Shell Nanoparticles of Fixed Core Diameter and Variable Shell Thicknesses
No full textWe have carried out extensive measurements on novel Fe3O4–γ-Fe2O3 core–shell nanoparticles of nearly similar core diameter (8 nm) and of various shell thicknesses of 1 nm (sample S1), 3 nm (sample S2), and 5 nm (sample S3). The structure and morphology of the samples were studied using X-ray diffraction (XRD), transmission electron microscopy (TEM), and selected area electron diffraction (SAED). The direct current (DC) magnetic measurements were carried out using a superconducting quantum interference device (SQUID). Exchange bias and coercivity were investigated at several temperatures where the applied field was varied between 3 and −3 T. Several key results are obtained, such as: (a) the complete absence of exchange bias effect in sample S3; (b) the occurrence of nonconventional exchange bias effect in samples S2 and S1; (c) the sign-change of exchange bias field in sample S2; (d) the monotonic increase of coercivity with temperature above 100 K in all samples; (e) the existence of a critical temperature (100 K) at which the coercivity is minimum; (f) the surprising suppression of coercivity upon field-cooling; and (g) the observation of coercivity at all temperatures, even at 300 K. The results are discussed and attributed to the existence of spin glass clusters at the core–shell interface
