Microplastic pollution is receiving increased attention due to the realization of its hazards to aquatic and human life. Researchers across the globe are attempting to remove microplastics before its entry into the ecosystem. Therefore, the present work focused on the removal of microplastic from water and studied the potential risks for marine organisms and the ecosystem. The removal of model microplastics, polypropylene (PP) and polyvinyl chloride (PVC), has been studied by using photo-Fenton process. ZnO nanorods coated with SnOx(x < 2) layer and decorated with zero valent iron (Fe-0) nanoparticles was used as heterogeneous catalyst for the removal of the microplastics in continuous water flow device. The obtained results demonstrated that high degradation efficiency of PP and PVC microplastics was achieved in a relatively short time and more than 95% of the average particle volume was reduced after 1 week of irradiation. The environmental impact of the photo-Fenton process of the microplastics degradation was investigated by using an ecotoxicological approach. An ecosafety screening has been performed through a series of experiments (bioassays) under controlled conditions, testing water samples after the photo-Fenton degradation of microparticles using a lab scale device. The ecotoxicological impact has been investigated by applying a battery of certified bioassays (UNI EN ISO/EPA standardized techniques) on aquatic organisms at different trophic levels (bacteria, algae, invertebrates). The results obtained on the three model organisms (A. fischeri, P. subcapitata, and D. magna) revealed no toxic effect for samples collected both before and after the photo-Fenton process, thus showing the absence of toxic by-products development during the degradation process.

The performance of biocide-based coatings for health care applications, using the drug delivery method, depends primarily on the diffusive properties of storage material. When the active component is ionic silver, supplied from silver nanoparticles, an additional dissolution step must occur in the bulk of the storage material. This article presents the silver release behavior of organic-inorganic sol-gel hybrid coatings and the effect of claynanoparticle composite, added in the sol-type formulation. Hybrid coatings were synthesized from the hydrolytic condensation of (3-glycidoxypropyl)-trimethoxysilane (GPTMS) and tetraethoxysilane in acidic media. Clay nanoparticles, previously silanized with GPTMS, and silver nitrate were used as additives in sol-gel formulations, alternatively. Coatings were deposited on microscope glass slides by the dip-coating process at a constant withdrawal rate and densified at 150 degrees C. Through small angle X-ray scattering from a synchrotronic source, and transmission electron microscopy, the structure of hybrid matrix, silver nanoparticles morphology and the storability behavior of silver nanoparticles under leaching conditions was analyzed. Silver releasing process was analyzed by following the evolution of silver nanoparticles remaining in the coatings, by UV-visible spectroscopy, and the increase of silver ions in the liquid medium, using inductively coupled plasma with optical emission spectroscopy. Microbiological studies showed that the lixiviated silver exhibited inhibitory properties against E. coli in LB broth. The clay nanoparticles worked as a stabilizing agent avoiding the agglomeration of silver both on the sols and on the surface of the thermally densified coatings.

In this work, graphene oxide–based tablets (GO-Tabs) were prepared by applying a thin layer of functionalized GO on a polyethylene substrate. The GO was functionalized with amine groups (–NH2) by poly(ethylene glycol)bis(3-aminopropyl) terminated (GO-NH2-PEG-NH2). The functionalized GO-Tabs were used for the extraction of ritonavir (RTV) in human saliva samples. RTV in plasma and saliva samples was analyzed using LC–MS/MS. Gradient LC system with MS/MS in the positive-ion mode [electrospray ionization (ESI+)] was used. The transitions m/z 721 → 269.0 and m/z 614 → 421 were used for RTV and the internal standard indinavir, respectively. This study determined the human immunodeficiency virus protease inhibitor RTV in human saliva samples using functionalized GO-Tab and LC–MS/MS, and the method was validated. The standard calibration curve for plasma and saliva samples was constructed from 5.0 to 2000 nmol L−1. The limit of detection was 0.1 nmol L−1, and the limit of quantification was 5.0 nmol L−1 in both plasma and saliva matrices. The intra- and inter-assay precision values were found to be between 1.5 and 5.8%, and the accuracy values ranged from 88.0 to 108% utilizing saliva and plasma samples. The extraction recovery was more than 80%, and the presented functionalized GO-Tabs could be reused for more than 10 extractions without deterioration in recovery.

Microplastic pollution of water and ecosystem is attracting continued attention worldwide. Due to their small sizes (≤5 mm) microplastic particles can be discharged to the environment from treated wastewater effluents. As microplastics have polluted most of our aquatic ecosystems, often finding its way into drinking water, there is urgent need to find new solutions for tackling the menace of microplastic pollution. In this work, sustainable green photocatalytic removal of microplastics from water activated by visible light is proposed as a tool for the removal of microplastics from water. We propose a novel strategy for the elimination of microplastics using glass fiber substrates to trap low density microplastic particles such as polypropylene (PP) which in parallel support the photocatalyst material. Photocatalytic degradation of PP microplastics spherical particles suspended in water by visible light irradiation of zinc oxide nanorods (ZnO NRs) immobilized onto glass fibers substrates in a flow through system is demonstrated. Upon irradiation of PP microplastics for two weeks under visible light reduced led to a reduction of the average particle volume by 65%. The major photodegradation by-products were identified using GC/MS and found to be molecules that are considered to be mostly nontoxic in the literature.

Efficient oxygen evolution reaction (OER) electrocatalysts are pivotal for sustainable fuel production, where the Ni-Fe oxyhydroxide (OOH) is among the most active catalysts for alkaline OER. Electrolyte alkali metal cations have been shown to modify the activity and reaction intermediates, however, the exact mechanism is at question due to unexplained deviations from the cation size trend. Our X-ray absorption spectroelectrochemical results show that bigger cations shift the Ni2+/(3+delta)+ redox peak and OER activity to lower potentials (however, with typical discrepancies), following the order CsOH>NaOH approximate to KOH>RbOH>LiOH. Here, we find that the OER activity follows the variations in electrolyte pH rather than a specific cation, which accounts for differences both in basicity of the alkali hydroxides and other contributing anomalies. Our density functional theory-derived reactivity descriptors confirm that cations impose negligible effect on the Lewis acidity of Ni, Fe, and O lattice sites, thus strengthening the conclusions of an indirect pH effect. It is commonly accepted that electrolyte alkali metal cations modify the catalytic activity for oxygen evolution reaction. Here the authors challenge this assumption, showing that the activity is actually affected by a change in the electrolyte pH rather than a specific alkali cation.

Investigations of Coptic mural paintings in historic churches and monasteries demand a deep understanding of the micro structure of the mural painting layers. The main objective of the present study is to study the efficiency of new avenues of computed X-ray tomography (CT Scan) and MATLAB in the analysis of Coptic mural paintings, either in the form of images or videos made to collect information about the physical characteristics of the material structure of the layers of mural paintings. These advanced techniques have been used in the investigation of samples of Coptic mural paintings dating back to the V-VIII century A.D, which have been collected from several locations in the Coptic monasteries in Upper Egypt. The application of CT-scanning is a powerful non-destructive tool for imaging and investigation which can be applied to the preservation of monuments made from many different materials. The second stage of research will be to characterize the materials through analytical techniques including XRD, XRF, EDX and FTIR to confirm the findings of CT scanning and to provide additional information concerning the materials used and their deterioration processes. This paper presents the results of the first pilot study in which CT scan and MATLAB have been utilized in combination for the non-destructive evaluation and investigation of Coptic mural paintings in Upper Egypt. The examinations have been carried out on mural painting samples from three important Coptic monasteries in Upper Egypt: the Qubbat Al Hawa Monastery in Aswan, the Saint Simeon Monastery in Aswan and the Saint Matthew the Potter Monastery in Luxor. This multi-stranded investigation has provided us with important information about the physical structure of the paintings, grains dimensions, grain texture, pore media characterization which include the micro porosity, BET and TPV, surface rendering, and calculation of the points in the surface through calculations completed using MATLAB. CT scanning assisted in the investigation and analyses of image surface details, and helped to visualize hidden micro structures that would otherwise be inaccessible due to over painting.

In this study, a novel sort of sample preparation sorbent was developed, by preparing thin layer graphene oxide tablets (GO-Tabs) utilizing a mixture of graphene oxide and polyethylene glycol on a polyethylene substrate. The GO-Tabs were used for extraction and concentration of omeprazole (OME) in human saliva samples. The determination of OME was carried out using liquid chromatography-tandem mass spectrometry (LC-MS/MS) under gradient LC conditions and in the positive ion mode (ESI+) with mass transitions of m/z 346.3 -> 198.0 for OME and m/z 369.98 -> 252.0 for the internal standard. Standard calibration for the saliva samples was in the range of 2.0-2000 nmol L-1. Limits of detection and quantification were 0.05 and 2.0 nmol L-1, respectively. Method validation showed good method accuracy and precision; the inter-day precision values ranged from 5.7 to 8.3 (%RSD), and the accuracy of determinations varied from -11.8% to 13.3% (% deviation from nominal values). The extraction recovery was 60%, and GO-Tabs could be re-used for more than ten extractions without deterioration in recovery. In this study, the determination of OME in real human saliva samples using GO-Tab extraction was validated.

Nanocomposite functionalized membranes were synthesized using surface functionalized mesoporous silica nanoparticles (MCM-NH2 or MCM-PEI) cross-linked to a modified polyacrylonitrile (mPAN) nanofibrous substrate for the removal of 1 mg L-1 of As(V); a concentration much higher than what has been reported for underground water in Argentina. Adsorption studies were carried out in batch mode at pH 8 with nanoparticles in colloidal form, as well as the nanoparticles supported on the modified PAN membranes (mPAN/MCM-NH2 and mPAN/MCM-PEI). Results indicate a twenty-fold improvement in As(V) adsorption with supported nanoparticles (nanocomposite membranes) as opposed to their colloidal form. The adsorption efficiency could be further enhanced by modifying the nanocomposite membrane surface with Fe3+ (mPAN/MCM-NH2-Fe3+ and mPAN/MCM-PEI-Fe3+) which resulted in more than 95% arsenic being removed within the first 15 minutes and a specific arsenic adsorption capacity of 4.61 mg g(-1) and 5.89 mg g(-1) for mPAN/MCM-NH2-Fe3+ and mPAN/MCM-PEI-Fe3+ nanocomposite membranes, respectively. The adsorption characteristics were observed to follow a pseudo-first order behavior. The results suggest that the synthesized materials are excellent for quick and efficient reduction of As(V) concentrations below the WHO guidelines and show promise for future applications.

In this work the photocatalytic degradation of pharmaceuticals (Ibuprofen, Cetirizine, and Naproxen) was evaluated using surface modified TiO2 nanoparticles immobilized on polyacrylonitrile/multiwall carbon nanotubes composite nanofibers. The photocatalytic degradation was studied under visible light (0.1 W/cm(2)) irradiation. Comparatively, the photocatalytic degradation of pharmaceuticals using PAN-CNT/TiO2-NH2 composite nanofibers was much more efficient than with PAN/TiO2-NH2 composite nanofibers under visible light irradiation. The results obtained showed that the photocatalytic efficiency of the studied pharmaceuticals is pH dependent in which more than 99% degradation was obtained at pH 2. Complete degradation of IBP, CTZ, and NPX was achieved within 200, 50, and 90 min, respectively under visible light.

In the present study, a new graphene based nanofibers material (Polyacrylonitrile/Graphene Oxide (PAN/GO)) was used for microextraction by packed sorbent (MEPS). The PAN/GO nanofiber was synthesized using the electrospinning technique. MEPS online with liquid chromatography-tandem mass spectrometry (LC-MS/MS) was utilized for the extraction and determination of two local anesthetic drugs (lidocaine, prilocaine) and their major metabolites (2,6-xylidine, o-toluidine) in human plasma samples. Parameters affecting the extraction efficiency were investigated and optimized (including sample pH, washing solution and elution solution). The validation of the method was based on FDA (Food and Drug Administration) guidelines for bioanalytical methods. The calibration curve ranged from 2.00 to 2000 nmol/L for lidocaine and prilocaine, and from 10.0 to 2000 nmol/L for 2,6-xylidine and o-toluidine. The coefficient of determination (R-2) values were 0.996, 0.995, 0.995, 0.996 (n = 3) for lidocaine, prilocaine, 2,6-xylidine and o-toluidine, respectively. The extraction recovery was 93.0% for lidocaine, 96.0% for prilocaine, 68.0% for 2,6-xylidine and 69.0% for o-toluidine. The limits of detection (LODs) were 0.25, 0.50, 2.50, 1.25 nmol/L for lidocaine, prilocaine, 2,6-xylidine and o-toluidine, respectively. The lower limits of quantification (LLOQs) were 2.0 nmol/L for lidocaine and prilocaine, and 10 nmol/L for 2,6-xylidine and o-toluidine, respectively. The accuracy values for the quality control (QC) samples were in the range of 91.0-111% for lidocaine, 92.0-118% for prilocaine, 84.0-98.0% for 2,6-xylidine and 82.0-90.0% for o-toluidine. The inter-day precisions for QC samples ranged from 7.0% to 11.8% for lidocaine, from 8.6% to 11.7% for prilocaine, from 8.0% to 10.0% for 2,6-xylidine and from 8.0% to 9.0% for o-toluidine. The matrix effect values were in the range of - 2.3% to - 8.6% for lidocaine, - 2.7% to - 10.2% for prilocaine, 4.8%-5.2% for 2, 6-xylidine and - 8.2% to 9.4% for o-toluidine.