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

Photoluminescence and dye adsorption mechanism of dehydrated carbon quantum dots

The role of oxygen-based functional groups in the photoluminescence of dehydrated carbon dots (DC) and the adsorption mechanism of dye molecules onto the surface of DC is investigated. DC was prepared from orange peel for the first time via the chemical dehydration effect of sulfuric and phosphoric acid at 180 C. We compared the emission spectra of DC in different solvents in great detail. The solvatochromism of DC in different solvents is discussed. The role of oxygen-based functional groups in the light emission process is examined. Adsorption of methylene blue (MB) on the surface of DC was studied at different contact times, pH, concentrations, and temperatures. In this work, we used Langmuir and Freundlich adsorption models for the analysis. Sorption kinetic data were found to fit well with the pseudo-second-order model. Our results also showed increased MB adsorption capability with temperature. The results are essential for the application of CQDs, such as wastewater treatment. &nbsp

Characterization of extracted bio-nano particles from date palm agro-residues

Mechanical downsizing of waste lignocellulosic fibers to small-size particles is a promising way to produce efficient reinforcing elements for bio-composites, both from commercial and environmental perspectives. This study specifically aims to make nano-sized lignocellulosic fillers from date palm agro-residues using a mechanical ball milling technique supplemented with liquid Nitrogen. The researchers aimed to obtain efficient reinforcing elements for bio-composites by fragmenting and downsizing waste lignocellulosic fibers. Several tests were conducted to evaluate and characterize the fillers' properties. The morphological analysis using TEM and FE-SEM showed that the microparticles had irregularly shaped particles with sizes ranging from 0.6 to 0.8 μm for micro-untreated particles and 0.22–0.32 μm for micro-treated particles. The nanoparticles had smaller particle sizes, with nano-untreated particles ranging from 80 to 122 nm and nano-treated particles ranging from 32 to 55 nm. XRD analysis revealed a boost in crystallinity due to the treatment process; (45 %) for micro-treated and (67 %) for nano-treated. TGA analysis indicated that the chemically treated fillers contributed to the improved thermal stability of the samples. Specifically, MT showed the best thermal stability due to increased crystallinity and stronger binding among the cellulose chains than that of NT