Evaluation of Hospital Wastewater Treatment Using Sewage Treatment Plant for Heavy Metals, Radionuclides, and Some Pharmaceuticals: A Case Study

This 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

Mononuclear Fe(III) Schiff Base Complex with Trans-FeO4N2 Chromophore of o-Aminophenol Origin: Synthesis, Characterisation, Crystal Structure, and Spin State Investigation

A new iron(III) complex (Et$_3$NH)$_2$[Fe(L)$_2$](ClO$_4$)·MeOH (1) where H$_2$L = 2-{(E)-[2-hydroxyphenyl)imino]methyl}phenol has been synthesised and characterised by single crystal XRD, elemental analysis and DC magnetic susceptibility measurements. The dianionic ligands L$^2$− coordinate in a tridentate fashion with the Fe(III) through their deprotonated pheno- lic oxygens and azomethine nitrogen atoms, resulting in a trans-FeO$_4$N$_2$ chromophore. Variable- temperature magnetic measurements were performed between 300 and 5 K under an applied field of 0.1 T and show that 1 is in the high spin state (S = 5/2) over the whole measured temperature range. This is confirmed by Mössbauer spectroscopy at 77 and 300 K

Maghemite (γ-Fe2O3) and γ-Fe2O3-TiO2 Nanoparticles for Magnetic Hyperthermia Applications: Synthesis, Characterization and Heating Efficiency

In 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

Mössbauer Study of Weathered H-meteorite from the Desert of Oman

A 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

Mononuclear Fe(III) Schiff Base Complex with Trans-FeO₄N₂ Chromophore of <i>o</i>-Aminophenol Origin: Synthesis, Characterisation, Crystal Structure, and Spin State Investigation

A new iron(III) complex (Et3NH)2[Fe(L)2](ClO4)·MeOH (1) where H2L = 2-{(E)-[2-hydroxyphenyl)imino]methyl}phenol has been synthesised and characterised by single crystal XRD, elemental analysis and DC magnetic susceptibility measurements. The dianionic ligands L2− coordinate in a tridentate fashion with the Fe(III) through their deprotonated phenolic oxygens and azomethine nitrogen atoms, resulting in a trans-FeO4N2 chromophore. Variable-temperature magnetic measurements were performed between 300 and 5 K under an applied field of 0.1 T and show that 1 is in the high spin state (S = 5/2) over the whole measured temperature range. This is confirmed by Mössbauer spectroscopy at 77 and 300 K

Coordination versatility of tridentate pyridyl aroylhydrazones towards iron : tracking down the elusive aroylhydrazono-based ferric spin-crossover molecular materials

The two potentially tridentate and monoprotic Schiff bases acetylpyridine benzoylhydrazone (HL 1) and acetylpyridine 4-tert-butylbenzoylhydrazone (HL 2) demonstrate remarkable coordination versatility towards iron on account of their propensity to undergo tautomeric transformations as imposed by the metal centre. Each of the pyridyl aroylhydrazone ligands complexes with the ferrous or ferric ion under strictly controlled reaction conditions to afford three six-coordinate mononuclear compounds [Fe II (HL) 2] (ClO 4) 2, [Fe II L 2] and [Fe III L 2] ClO 4 (HL = HL 1 or HL 2) displaying distinct colours congruent with their intense CT visible absorptions. The synthetic manoeuvres rely crucially on the stoichiometry of the reactants, the basicities of the reaction mixtures and the choice of solvent. Electrochemically, each of these iron compounds exhibits a reversible metal-centred redox process. By all appearances, [Fe III (L 1) 2]ClO4 is one of only two examples of a crystallographically elucidated iron(III) bis-chelate compound of a pyridyl aroylhydrazone. Several pertinent physical measurements have established that each of the Schiff bases stabilises multiple spin states of iron; the enolate form of these ligands exhibits greater field strength than does the corresponding neutral keto tautomer. To the best of our knowledge, [Fe III (L 1) 2]ClO 4 and [Fe III (L 2) 2 ]ClO 4 are the first examples of ferricspin crossovers of aroylhydrazones. Whereas in the former the spin crossover (SCO) is an intricate gradual process, in the latter the 6 A 1 ↔ 2 T 2 transition curve is sigmoidal with T 1 2 ~ 280 K and the SCO is virtually complete. As regards [Fe III (L 1) 2]ClO 4, M̈ossbauer and EPR spectroscopic techniques have revealed remarkable dependence of the spin transition on sample type and extent of solvation. In frozen MeOH solution at liquid nitrogen temperature, both iron(III) compounds exist wholly in the doublet ground state