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Ensuring access to clean and safe water is a critical aspect of human survival, yet water pollution caused by organic contaminants remains a significant global challenge. Adsorption, which involves using an adsorbent material to remove pollutants, is a well-established technique for purifying water from organic contaminants. However, the adsorption capacity of the material decreases over time as it becomes saturated with the adsorbed pollutants. In this study, the researchers used montmorillonite, a naturally occurring and readily available clay mineral, as an adsorbent material for the removal of tetracycline from water sources. The results demonstrate that montmorillonite is an efficient adsorbent, with complete adsorption of tetracycline achieved within 40 minutes of stirring using just 0.1g of montmorillonite with tetracycline (100 mL, 100 ppm). Furthermore, the study presents a novel approach to regenerate and activate used montmorillonite through thermal combustion, allowing for its reuse in further adsorption processes. The stability of the annealed montmorillonite was confirmed by characterization techniques such as TGA and FT-IR. The findings suggest that montmorillonite is a sustainable, low-cost, and effective adsorbent material for the removal of tetracycline from water sources and holds potential for removing other organic pollutants (such as pesticides, insecticides, herbicides, dyes, pharmaceuticals), presenting a valuable addition to existing water treatment methods.

Ensuring access to clean and safe water is a critical aspect of human survival, yet water pollution caused by organic contaminants remains a significant global challenge. Adsorption, which involves using an adsorbent material to remove pollutants, is a well-established technique for purifying water from organic contaminants. However, the adsorption capacity of the material decreases over time as it becomes saturated with the adsorbed pollutants. In this study, the researchers used montmorillonite, a naturally occurring and readily available clay mineral, as an adsorbent material for the removal of tetracycline from water sources. The results demonstrate that montmorillonite is an efficient adsorbent, with complete adsorption of tetracycline achieved within 40 minutes of stirring using just 0.1g of montmorillonite with tetracycline (100 mL, 100 ppm). Furthermore, the study presents a novel approach to regenerate and activate used montmorillonite through thermal combustion, allowing for its reuse in further adsorption processes. The stability of the annealed montmorillonite was confirmed by characterization techniques such as TGA and FT-IR. The findings suggest that montmorillonite is a sustainable, low-cost, and effective adsorbent material for the removal of o from water sources and holds potential for removing other organic pollutants (such as pesticides, insecticides, herbicides, dyes, pharmaceuticals), presenting a valuable addition to existing water treatment methods.

Proposed treatment processes of OMWW have not been efficient in decreasing its high toxicity or lowering its ecological impact. Bioremediation using microorganisms might be considered an environmentally friendly alternative. In this work, four fungal isolates were tested for their efficacy in lowering the toxicity of OMWW. Results of this work showed that fungal isolates were able to grow on OMWW. However, only one isolate (OMWW2) showed significant lowering in total phenols from 159.27 mg/ml (in controlled untreated water) to 57.75 mg/ml. The treated OMWW was tested on seed gemination of tomato. The results showed 83% germination rates in the presence of treated OMWW compared with 0% rates in nontreated OMWW. The results showed also that OMWW could be used as a supplement fertilizer to the presence of macronutrient and micronutrient. This work provides a promising future treatment OMWW. Further studies are needed to evaluate the possible use of OMWW in horticulture.

Interests and concerns on environmental issues have attracted much attention over the past few decades. This is in harmony with the growing understanding of environmental impacts associated with human activities and their role in degrading ecosystems. In line with these concerns, considerable advances in science and technology to assess, mitigate, or lessen these adverse impacts have emerged (i.e., environmental impact assessment (EIA) methodologies). The involvement of EIA in sustainable development has become a prevalent topic in research in either developed and developing countries. The present work investigated the research status, development trends, and hotspots of EIA in a region with massive environmental challenges; the Arab world. Bibliometric analysis and visualization mapping were utilized with an objective of revealing and evaluating the developments in knowledge on EIA from the Arab world. A sum of 595 documents was the productivity of the Arab world on EIA (2.1% of total global productivity). Most of the studies were performed by scholars in Egypt (143 documents; 24.0%), followed by Saudi Arabia (96 documents; 16.1%), and Tunisia (68 documents; 11.4%). France, the USA, and the UK were, respectively, the most collaborated countries with the Arab world on EIA. Most of the publications on EIA were in prestigious journals in relation to environmental sciences. King Abdulaziz University, Saudi Arabia and University of Kuwait were the most productive institutions (24 documents/institution). Topics in relation to assessing different environmental impacts on the quality and quantity of water will continue to be vital themes of research. While, the utilization of remote sensing, geographic information systems, risk assessment, life cycle assessment, bioaccumulation, and biomarkers techniques in assessing environmental impacts will continue to be dominant as efficient tools in conducting EIA related research. The outcomes displayed, in general, a rapidly and steadily rising interests on EIA. However, the development of regional experience, increasing of funds and advancing of competencies will further promote research activities on EIA.

Many natural materials have the ability to rotate the polarization level of linearly polarized laser beam and pass through it. This phenomenon is called optical activity. In the event that a light beam (linearly polarized) passes through an optically active material, such as a quartz crystal, and projected vertically on the optical axis, the output beam will be polarized equatorially, and the vibration level will rotate at a certain angle [1], [2], [3]. A number of crystals, liquids, solutions, and vapors rotate the electric field of linearly polarized light that passes through them [4], [5], [6], [7]. Many different physical effects are applied to optical isotropic and transparent materials that cause them to behave as optical active materials, where they are able to rotate the polarization level of the polarized light linearly and pass through it [8], [9], [10]. These effects include mechanical strength, electric field, and magnetic field. By placing one of these effects on an optically transparent medium, it changes the behavior of the light travelling through it [11].

Non-steroidal anti-inflammatory drugs (NSAIDs) are widely prescribed for the treatment of various types of inflammatory conditions. Diclofenac is a very common NSAID that is utilized to relieve pain and reduce fever and, most importantly, inflammation. However, it suffers from low water solubility and a low dissolution profile. Therefore, we aim to develop a new drug delivery system based on the synthesis of amphiphilic structures that are capable of self assembling into nano-micelles which will be a water-soluble delivery system for the diclofenac. The amphiphilic structure consists of a hydrophilic moiety of triethylene glycol (TEG), polyethylene glycol PEG 400, or PEG 600 linked with the hydrophobic drug diclofenac through an ester linkage. The diclofenac derivatives were successfully synthesized as confirmed by nuclear magnetic resonance. Moreover, the formation of the micellar structure of the synthesized amphiphilic derivatives was confirmed by atomic force microscopy obtaining a spherical shape of the micelles with average diameters of 200 nm for Dic-PEG400-Dic, and 110 nm for Dic-PEG600-Dic. The critical micelle concentration has been determined as 2.7 × 10−3 mg mL−1 for Dic-PEG400-Dic, and 1 × 10−4 mg mL−1 for Dic-PEG600-Dic. The in vitro diclofenac release profile by esterase enzyme was conducted and showed almost complete conversion to free diclofenac within 35 h in the case of Dic-PEG400-Dic micelles and more than 85% of Dic-PEG600-Dic micelles. Then the anti-inflammatory activity was determined by testing the TNF-α production in LPS-stimulated Balb/c mice. Diclofenac micelles significantly suppressed TNF-α production after a 5 mg kg−1 dose was given. The developed micelles showed TNF-α inhibition up to 87.4% and 84% after 48 hours of treatment in the case of Dic-PEG400-Dic and Dic-PEG600-Dic micelles respectively in comparison to 42.3% in the case of diclofenac alone. Dic-PEG400-Dic micelles showed the most potent anti-inflammatory activity with improved TNF-α suppression through time progress. Therefore, the developed nano-micelles provide a facile synthetic approach to enhance diclofenac water solubility, improve the anti-inflammatory effect and achieve a sustained release profile to get better patient compliance.

Bacterial deactivation by cell-wall rupturing is widely described. Complete mineralization of both aqueous gram-positive Staphylococcus aureus and gram-negative Klebsiella pneumoniae, leaving no organic species, is described here for the first time. Solar-simulated radiation (with ~ 5% UV), with ZnO nanoparticle photocatalyst, is used. In addition to complete bacterial deactivation (~ 100%), their mineralization is achievable with time. Both bacteria, with thick and thin peptidoglycan layers, are mineralized. In thicker walled S. aureus, ~ 72% mineralization is achievable, while in thinner walled K. pneumoniae, mineralization is ~ 85%. Anthocyanin-sensitized ZnO shows higher catalytic efficiency under purely visible light, while pristine ZnO particles are more effective under simulated solar radiation. The results show the feasibility of using direct solar radiation in photocatalytic water disinfection without the need to use other more costly and hazardous methods. The study is especially useful to many societies having limited access to safe drinking water.

ZnO nanoparticles, stacked on the bottom of a glass dish, were used as a catalyst for the photodegradation of aqueous 2-chlorophenol (2-CP) contaminant. Solutions of 2-CP at different concentrations and pH values were passed over the ZnO film under simulated solar light. The effect of the light intensity on the contaminant photodegradation rate was investigated. The photodegradation efficiency was evaluated based on the percentage degradation, turnover number, turnover frequency, and quantum yield. The reaction efficiency parameters showed no significant variation when changing the pH across moderate values (neutral, slightly basic, and slightly acidic). Complete mineralization of the contaminant to CO2, H2O, and other minerals was confirmed by various analytical methods including high-performance liquid chromatography, ultraviolet–visible (UV–Vis) spectroscopy, and total organic carbon measurements. The continuous flow method applied in this work showed promising results in terms of safe removal of 2-CP from water at laboratory scale. More study of this method is needed to enable its use at larger, pilot plant scale.

A coronavirus disease-19 (COVID-19) caused by a novel coronavirus has appeared in China by the end of 2019 and later recognized as a global pandemic. This pandemic has evolved as a global public health menace. It has affected every aspect of human life. In line with these concerns, governments and the scientific community react promptly to the outbreak of this pandemic. These efforts are devoted to develop vaccine and curative medicines. Further efforts are dedicated to assessing the impacts of the pandemic in relation to socioeconomic, psychological, and environmental dimensions. In this regard, it is important to follow up developments and research activities on this global issue. The present work intended to tracking the current hotspots and research trends on COVID-19 in environmental fields. Bibliometric analysis and visualization mapping were utilized with the objective of revealing and evaluating the developments in knowledge on COVID-2019 and its impacts based on a collection of environmental sources. A sum of 729 documents were collected from Scopus database limiting to environmental sources only. Of all these publications, 563 (77.2%) were articles, 56 (7.7%) were reviews, and 110 (15.0%) were others. China has the highest share of publications (163; 22.4%). It is followed by the USA (139; 19.15), and Italy (110; 15.1%). Most publications on COVID-19 were in prestigious journals. The most productive institution at global level was Chinese Academy of Sciences, China (24 documents; 3.3%). The most prevalent topics are in relation to impacts of the pandemic on air quality, mental health, psychological, and economic aspects. The development of these topics is based on cross-sectional studies, evidence-based tools, remote sensing, satellite mapping, geographic information systems, market analysis and sampling. The progress of environmental research on COVID-19 will guide the development of global environmental strategies to control future global environmental risks.

Olive oil milling, widely practiced in Mediterranean countries, including Palestine, yields the so-called olive mill waste water (OMWW) or Zebar (Zibar). The waste contains minerals and organic materials (including phenols and polyphenols) which undergo continuous oxidation and cause environmental hazards if not well managed. This work basically aims at purifying surface waters, intentionally pre-contaminated with OMWW organic contaminants. Fate of other mineral ions present in the contaminated water is also investigated. ZnO nanoparticles, deposited as films onto glass reactor bottom (165 cm2 area), are described as catalyst for photodegradation of the organic contaminants, in a continuous flow reaction mode (gravity fed, typically at flow rate 3.5 mL/min). Two types of ZnO materials, namely commercial ZnO onto glass (C–ZnO/Glass) and synthetic ZnO supported onto clay and deposited on glass (Syn–ZnO/Clay/Glass), have been examined. The Syn–ZnO/Clay/Glass catalyst is slightly more efficient in removing organic contaminants (~ 43%), compared to the C–ZnO/Glass (41%) in 30 h. Different reaction parameters have been investigated, such as waste dilution factor, exposure duration, pH and catalyst recovery and reuse.

This article describes in detail the numerical modeling of a CZTS (copper zinc tin sulfide) based kesterite solar cell. The Solar Cell Capacitance Simulator -one-dimension (SCAPS-1D) software was used to simulate MO/CZTS/CdS/ZnO/FTO structured solar cells. The parameters of different photovoltaic thin-film solar cells are estimated and analyzed using numerical modeling. The effects of various parameters on the performance of the photovoltaic cell and the conversion efficiency are discussed. Since the response of the solar cell is also contingent on its internal physical mechanism, J-V characteristic measures are insufficient to characterize the behavior of a device. Different features, as well as different potential conditions, must be considered for simulation, disregarding the belief in the modeling of a solar cell. With a conversion efficiency of 25.72%, a fill factor of 83.75%, a short-circuit current of 32.96436 mA/cm2 and an open-circuit voltage of 0.64V, promising optimized results have been achieved. The findings will be useful in determining the feasibility of fabricating high-efficiency CZTS-based photovoltaic cells. The efficiency of a CZTS-based experimental solar cell is also discussed. First, the effects of experimentally developed CZTS solar cells are simulated in the SCAPS-1D environment. The experimental results are then compared to the SCAPS-1D simulated results. The conversion efficiency of an optimized system increases after cell parameters are optimized. Using one-dimensional SCAPS-1D software, the effect of system parameters such as the thickness, acceptor and donor carrier concentration densities of absorber and electron transport layers, and the effect of temperature on the efficiency of CZTS-based photovoltaic cells is investigated. The proposed results will greatly assist engineers and researchers in determining the best method for optimizing solar cell efficiency, as well as in the development of efficient CZTS-based solar cells.

Cadmium telluride (CdTe), a metallic dichalcogenide material, was utilized as an absorber layer for thin film–based solar cells with appropriate configurations and the SCAPS–1D structures program was used to evaluate the results. In both known and developing thin film photovoltaic systems, a CdS thin–film buffer layer is frequently employed as a traditional n–type heterojunction partner. In this study, numerical simulation was used to determine a suitable non–toxic material for the buffer layer that can be used instead of CdS, among various types of buffer layers (ZnSe, ZnO, ZnS and In2S3) and carrier concentrations for the absorber layer (NA) and buffer layer (ND) were varied to determine the optimal simulation parameters. Carrier concentrations (NA from 2 × 1012 cm−3 to 2 × 1017 cm−3 and ND from 1 × 1016 cm−3 to 1 × 1022 cm−3) differed. The results showed that the use of CdS as a buffer–layer–based CdTe absorber layer for solar cell had the highest efficiency (%) of 17.43%. Furthermore, high conversion efficiencies of 17.42% and 16.27% were for the ZnSe and ZnO-based buffer layers, respectively. As a result, ZnO and ZnSe are potential candidates for replacing the CdS buffer layer in thin–film solar cells. Here, the absorber (CdTe) and buffer (ZnSe) layers were chosen to improve the efficiency by finding the optimal density of the carrier concentration (acceptor and donor). The simulation findings above provide helpful recommendations for fabricating high–efficiency metal oxide–based solar cells in the lab.

Photovoltaics (PVs) show high conversion efficiency in renewable energy. However, PV systems demand advanced preparations and relatively large amounts of staring materials. Photoelectrochemical (PEC) systems, with monolithic semiconductor (SC) electrode/Redox couple interface, emerged, but still demand special preparation conditions and relatively large amounts of starting materials. Polycrystalline film electrodes, are studied as replacement for monolithic SC electrodes, both theoretically and experimentally. Examples are dye-sensitized solar cells (DSSCs) and metal chalcogenides. With narrow-to-medium band gaps, metal chalcogenides are suitable for the abundant visible solar light. However, polycrystalline film electrodes suffer major shortcomings. Pristine films show low conversion efficiency. Being polycrystalline, they have low carrier mobility. They are also unstable to photo-corrosion, due to charge build-up in the space charge layer (SCL). Enhancement of polycrystalline film electrode PEC performance and stability was reported using different methods. Among those, charge transfer catalysis at the film electrode surface, is focused here. The modification involves attaching electroactive species to the electrode surface. Ability of electroactive species to behave as charge transfer catalysts at the solid/liquid interface is discussed. By such behavior, the catalysts speed up charge transfer and consequently increase photocurrent. Moreover, charge build-up in the SCL is prevented by quick charge transfer, which protects the electrode surface from photo-corrosion. Ability of charged electroactive species to shift flat band edge position, with its consequences, is also described. Recommended features of an effective catalyst species for PEC systems are described together with recommendations for more future research in the field.

ZnO nanoparticles have been effectively used in water disinfection from two common types of gram-positive (Enterococcus faecium) and gram–negative (Proteus mirabilis) bacteria under simulated solar radiations by inactivation. Complete mineralization of organic contents that leach out of inactivated bacteria has also been achieved leaving no soluble organic matter in water. Bacterial inactivation and complete mineralization have been confirmed by plate counting, high performance liquid chromatography and total organic content measurement. Effects of different reaction parameters (pH, temperature, bacterial concentration, reaction time and ZnO catalyst loading) have all been studied. Control experiments with Cut-off filters confirm the role of the UV tail in solar simulated light in the photocatalytic process. The results highlight the feasibility of using ZnO photocatalyst in complete disinfection of water from both hazardous Enterococcus and Proteus mirabilis bacteria, leaving no organic matters after degradation.

Prediction of performance of traditional, reformulated, and novel oral formulations in adults and pediatrics is of great importance. This study was conducted to assess solubility of celecoxib in age-appropriate fasted- and fed-state gastric and intestinal biorelevant media, classify celecoxib into biopharmaceutical classification system (BCS), and assess the effects of age-related developmental changes in the composition and volume of gastrointestinal fluids on the solubility and performance of oral formulations containing celecoxib. Solubility of celecoxib was assessed at 37°C in the pH range specified by the BCS-based criteria in 13 age-appropriate biorelevant media reflective of the gastric and proximal small intestinal environment in both fasted and fed states in adults and different pediatric subpopulations. A validated HPLC-UV method was used to quantify celecoxib. Experimental and computational molecular descriptors and in vivo pharmacokinetic data were used to assign the permeability class of celecoxib. Celecoxib belonged to BCS class 2. The pediatric to adult solubility ratios were outside the 80-125% boundaries in 3 and borderline in 1 biorelevant media. Significant age-related variability could be predicted for oral formulations containing celecoxib intended for pediatric use. Findings of this study indicated that the criteria used in the adult BCS might not be directly applied to pediatric subpopulations.

Saliva is a biofluid that can easily be obtained and used for biomonitoring lead levels in occupationally and environmentally exposed individuals. The aims of this study were to determine salivary lead levels among workers in different industrial areas in the West Bank of Palestine and investigate the association between sociodemographic and occupational characteristics of the workers and their salivary lead levels. Salivary samples were obtained from workers in different industrial areas in metal-free polyethylene tubes. The samples were analyzed for their lead contents using a pre-validated inductively coupled plasma-mass spectrometric method. A total of 97 salivary samples were analyzed. The median salivary lead level was 1.84 μg/dL an IQR of 5.04 μg/dL. Salivary lead levels were significantly higher in workers who were 40 years and older (p value = 0.031), had 3 children or more (p value = 0.048), worked in repair workshops (p value = 0.012), worked in industrial areas for 20 years or more (p value = 0.048), did not consume fruits on regular basis (p value = 0.031), and smoked for 30 years or more (p value = 0.013). Multiple linear regression showed that smoking of 30 years old or more was a significant (p value

Commercial and laboratory-prepared ZnO nanoparticles are assessed here as a photocatalyst in photodegradation of aqueous 2-chlorophenol under direct sunlight. Kaolinite is used as a support for ZnO to enable its recovery after reuse. The composite ZnO/kaolinite is prepared by growing ZnO nanoparticles directly on kaolinite surface and is characterized by a number of methods such as electronic absorption spectra, photoluminescence spectra, X-ray diffraction and scanning electron microscopy. All ZnO systems (commercial, synthetic and supported) exhibit the wurtzite phase. The composite ZnO/kaolinite shows higher photocatalysis efficiency in 2-chlorophenol degradation over both commercial and synthetic ZnO powders. The composite ZnO/kaolinite is also easier to recover and reuse, showing no observable loss in its catalyst efficiency even after five cycles. These features highlight the merit of using composite ZnO/kaolinite as photocatalyst in water purification with direct sunlight for the first time. All catalyst systems are more efficient in basic media (pH ~ 8.5) than in neutral and acidic media, as rationalized by the point of zero charge concepts here. Moreover, the composite ZnO/kaolinite shows enhanced catalytic efficiency in 2-chlorophenol photodegradation in a wider pH range, compared to other counterparts, which shows another added value.

Drinking-water contamination with nitrate ions is inevitable and wide spreading, which demands feasible removal. Water de-nitration by potentiostatic electroreduction is described here. A novel electrocatalyst based on nano-copper particles, supported onto multi-walled carbon nanotubes (MWCNTs), and spray-deposited onto fluorine doped tin oxide-glass substrates, is described. The Cu/MWCNT/FTO electrode has been characterized by several methods and assessed as a working electrode in aqueous nitrate ion electroreduction, in comparison with MWCNT sprayed on FTO (MWCNT/FTO) with no copper. Comparison with earlier reported electrodes is also described. XRD patterns confirm the presence of nano-copper crystallites, in the electrode, with average size ⁓45 nm. Within 2 h of electrolysis, Cu/MWVNT/FTO exhibits more than 65% removal of nitrate at -1.80 V (vs. SCE). In longer time (7 h) the electrode completely converts the nitrate into N

Correction for ‘Optical properties and photoactivity of carbon nanodots synthesized from olive solid wastes at different carbonization temperatures’ by Shadi Sawalha et al., RSC Adv., 2022, 12, 4490–4500, https://doi.org/10.1039/D1RA09273A.

Waste cadmium sulfide (CdS) film electrodes, originally deposited onto glass/fluorine doped tin oxide (glass/FTO) substrates, were used to prepare recycled CdS film electrodes. The waste glass/FTO/CdS were processed in acidic media to recover the glass/FTO substrates, the Cd2+ ions (in the acidic solutions) and the gaseous H2S (recaptured in basic media). All components of the waste electrodes were thus recovered. The recovered glass/FTO and the Cd2+ ions were then reused to produce new recycled glass/FTO/CdS electrodes by chemical bath deposition. The produced films were then characterized by X-ray diffractometry, scanning electron microscopy, electronic absorption spectroscopy and other techniques. The Cd2+ ions were recovered with efficiency higher than 90% from the waste films, as observed from atomic absorption spectrometry. The recycled films were assessed in photo-electrochemical conversion of light to electricity, and exhibited comparable efficiency to those freshly prepared from authentic starting materials and other literature values. Photoelectrochemical characteristics for the recovered films were further enhanced by avoiding stirring of the chemical deposition bath during preparation. The results manifest the feasibility of recycling CdS electrodes and enhancing their photo-electrochemical characteristics by simple low cost methods. Both environmental protection and economic goals can thus be potentially achieved.

The numerical modeling of a copper zinc tin sulfide (CZTS)-based kesterite solar cell is described in detail in this article. To model FTO/ZnO/CdS/CZTS/MO structured solar cells, the Solar Cell Capacitance Simulator-one-dimension (SCAPS-1D) program was utilized. Numerical modeling was used to estimate and assess the parameters of various photovoltaic thin film solar cells. The impact of different parameters on solar cell performance and conversion efficiency were explored. Because the response of a solar cell is partly determined by its internal physical mechanism, J-V characteristic characteristics are insufficient to define a device’s behavior. Regardless of the conviction in solar cell modeling, variable attributes as well as many probable conditions must be handled for simulation. Promising optimized results were obtained with a conversion efficiency of (η% = 25.72%), a fill factor of (FF% = 83.75%), a short-circuit current of (JSC = 32.96436 mA/cm2), and an open-circuit voltage of (VOC = 0.64 V). The findings will aid in determining the feasibility of manufacturing high-efficiency CZTS-based solar cells. First, in the SCAPS-1D environment, the impacts of experimentally constructed CZTS solar cells were simulated. The experimental data was then compared to the simulated results from SCAPS-1D. After optimizing cell parameters, the conversion efficiency of the improved system was observed to rise. The influence of system factors, such as the thickness, acceptor, and donor carrier concentration densities of the absorber and electron transport layers, and the effect of temperature on the efficiency of CZTS-based photovoltaic cells, was explored using one-dimensional SCAPS-1D software. The suggested findings will be extremely useful to engineers and researchers in determining the best method for maximizing solar cell efficiency, as well as in the development of more efficient CZTS-based solar cells.

Zinc oxide (ZnO) nano-particles were chemically deposited onto montmorillonite (MONT) clay particles. The composite ZnO@MONT was then characterized and used as a catalyst for photo-degradation of aqueous tetracycline. Unlike earlier studies, solar simulated light can be effectively used in this work. The composite shows high efficiency as adsorbent and as a photo-degradation catalyst. Both adsorbed and dissolved tetracycline molecules undergo mineralization under the photo-catalytic conditions, and up to 94% of the contaminant gross amount is completely mineralized. Other forms of ZnO particles, commercial ZnO and synthetic ZnO particles were examined in separate experiments. The ZnO@MONT is superior to both pristine counterparts. The ability of tetracycline to sensitize the supported ZnO particles, to solar simulated light, before being photo-degraded itself, is discussed here for the first time. In addition to enhanced catalytic activity of the ZnO@MONT, the composite can be efficiently recovered and reused with no significant loss of efficiency.

International audience; For the first time, pristine ZnO nano-particles can be used as effective catalyst for water disinfection by killing and complete mineralization of two gram negative bacteria with direct solar light. Just like in earlier studies, pristine nano-size ZnO particles have shown anti-bacterial activity against two types of gram negative bacteria, E. coli and P. aeruginosa, where up to 20% of the former and 25% of the latter have been killed in the dark. Under direct solar radiation, the pristine ZnO particles readily catalyzed bacterial photo-degradation. While earlier studies were mostly limited to bacterial death and growth inhibition by pristine ZnO particles, the results describe for the first time how bacteria and their organic content can be completely photo-mineralized by direct solar radiations in 60 min. Only the bacterial cell wall fragments resisted the photo-degradation process. Under the reaction conditions, the degradation occurred by the UV tail of the direct solar light, where the ZnO nano-particles behaved as photo-catalysts. The results show the added value of using ZnO nano-particles as photo-catalysts in water disinfection strategies, leaving no resulting organic molecules in water.

Background Hen eggs contaminated with lead can be harmful to the health of children and adults. The objective of this pilot study was to investigate if sub-chronic treatment with ascorbic acid can reduce lead levels in the different parts of hen eggs after intentionally exposing the laying hens to a concentrated source of lead. Methods Clinically normal mixed-breed egg laying hens (n = 18) were used in this pilot study. Hens were exposed to a concentrated source of lead (200 mg/kgbody weight/day lead acetate) for 1 week. Subsequently, egg laying hens were either treated with sub-chronic doses of ascorbic acid (500 mg/kgbody weight/day) or left untreated for 4 weeks. Lead levels were assessed in egg-shell, egg-albumen, and egg-yolk samples using a graphite furnace atomic absorption spectrophotometer. Results Lead levels increased significantly (p-value p-value Conclusions Findings of this pilot study showed that sub-chronic treatment of egg laying hens with ascorbic acid can reduce lead levels in different egg parts after intentional exposure to a concentrated source of lead. Supplementing feedstuffs and water with sources of ascorbic acid could be beneficial in reducing lead levels in hen egg tissues following environmental exposure. Further studies are still required to investigate if ascorbic acid can reduce lead levels in other chicken tissues.

In this study, Zinc Telluride (ZnTe)-based solar cells, which are metallic dichalcogenide materials, are used as a solar cell absorbent with the formation appropriate for solar cell use. The data has been analyzed by SCAPS-1D structures software. The replacement of Cadmium Sulfide CdS (buffer) layer by other green and save suitable materials has been investigated. The substituted buffer layers have been ZnSe, ZnS, CdSe, and In2S3. The higher device performance efficiency parameters have been found out when using CdS and ZnSe as buffer layers. SCAPS-1D shows that the optimal p-n junction device eff]iciency parameters have been achieved when the ZnTe (absorber) layer thickness is between 1200-1500 nm, while the ZnSe (buffer) layer thickness is between 20-60 nm, and the thickness of ZnO:Al (window) layer is 25 nm. The results of the simulation provide important hints that may enhance the performance of the cell with empirical studies useful in practical implementation.

The Expert Systems With Applications (ESWA) is a leading journal in the fields of computer science and engineering. Motivated by its outstanding performance, this paper seeks to develop a comprehensive overview of research activities in ESWA since its inception in 1990. In this regard, bibliometric techniques have been utilized to characterize the status quo, dynamics, and development trends of research patterns in ESWA. In doing so, the work used Scopus database as a source of data required. A data visualization software, visualization of similarities (VOS) viewer, was used to map the bibliographic material. The Scopus database yielded 12,254 documents published in ESWA from 105 countries with an average of 408 documents/year. The most productive country was Taiwan (2,069 documents; 17.0%). National Cheng Kung University, Taiwan, was the most productive institution (219 documents; 1.8%). The major topics which will continue to be active include genetic algorithms, data mining, neural networks, support vector machines, classification and machine learning, feature selection, particle swarm optimization, fuzzy logic, and clustering. The outcomes underline the significant growth of ESWA through time. The vitality of topics addressed in ESWA to solve real-world problems boosts the progress and advancements of knowledge in this journal.

International audience; This communication describes for the first time how nano-size particles, sensitized with natural dye molecules of anthocyanin, can be used as catalysts in photo-degradation of gram negative Escherichia coli bacteria in water. The naked ZnO nano-particles degraded up to 83% of the bacteria under solar simulator light, while the dye-sensitized particles increased the bacterial loss by ∼10%. Solar simulator light includes about 5% of UV tail (shorter than 400 nm) which means that both UV and visible light (longer than 400 nm) radiations could be involved. When a cut-off filter was used, the naked ZnO caused only 40% bacterial loss, in accordance with earlier literature that described killing of bacteria with ZnO particles both in the dark and under light. With the cut-off filter, the sensitized ZnO particles caused higher than 90% bacterial loss, which confirms sensitization of the ZnO particles to visible light. Moreover, the results show that the catalyzed photo-degradation process causes mineralization of the bacteria and their organic internal components which leach out by killing. The catalyst can be recovered and reused losing ∼10% of its activity each time due to mineralization of the dye molecules. However, catalyst activity can be totally regained by re-sensitizing it with the anthocyanin dye. The effects of different experimental conditions, such as reaction temperature, pH, bacterial concentration and catalyst amount together with nutrient broth and saline media, will be discussed together with the role of the sensitizer.

Nano-powders of commercial ZnO and TiO2 were investigated as photo-catalysts for mineralization of methylene blue (MB) in aqueous media. Comparative study was performed under solar-simulated light at room temperature and neutral conditions. Both systems showed activity and caused complete mineralization of the reacted MB molecules of low concentrations. The ZnO system showed much higher catalytic efficiency than the TiO2 counterpart. Spectrophotometric analysis of the reaction mixture showed that up to 100% removal of MB was achieved by ZnO catalyst in 60 min, whereas the TiO2 caused only 50% removal after the same time exposure. The UV light present in the solar simulator light (with about 5%) was responsible for mineralization of MB. Due to its higher efficiency, the ZnO system was then considered the catalyst of choice, where effects of different reaction parameters have been studied including: value of pH, temperature, light intensity, catalyst amount and MB concentration. The catalyst efficiency was measured by calculating values of turn-over number (TN), and quantum yield, after 30 min. The ZnO catalyst was isolated after reaction cessation and re-used for three times, where the catalyst retained up to 95% of its efficiency. The results show the potential value of using ZnO as a photo-catalyst for mineralization of MB in water with solar light. تهدف هذه الدراسة لتقيم قدرة حبيبات أكسيد الزنك وأكسيد التيتانيوم النانومترية على تحطيم صبغة الميثيل الازرق في المحاليل المائية. تمت هذه المقارنة باستخدام مصدر ضوئي مضاهي لضوء الشمس على درجة حرارة الغرفة وحامضية معتدلة. حيث أبدى الحفازان قدرة على تحطيم صبغة الميثيل الأزرق، الا أن أكسيد الزنك اظهر كفاءة أكبر مقارن بأكسيد التيتانيوم. التحليل الضوئي لنتائج التفاعل أظهرت التحطيم شبه الكامل ~100% للصبغة في حالة أكسيد الزنك خلال ساعة من التعرض للضوء، بينما استطاع أكسيد التيتانيوم من تحطيم 50% من الصبغة بعد التعرض لنفس الفترة من الضوء. عملية تحطيم الملوثات ناتجة عن تحفيز الحفازات بالأشعة فوق البنفسجية شحيحة التوفر في الضوء الشمسي الواصل الى الارض. تم دراسة بعض المتغيرات مثل تاثير درجة الحموضة ودرجة الحرارة وكثافة الضوء وكمية الحفاز المستخدم وتركيز صبغة الملوث على معدل ازالة الصبغة من المياه. وابدى استخدام اكسيد الزنك لعدة مرات متتالية كفاءة ثابتة نسبياً للعمل على تحطيم الملوث.

In this paper, SCAPS-1D simulation program is used to calculate the effect of layers thickness of Mo/CdTe/CdS/ITO device on the solar cell performance parameters (short-circuit current density Jsc, open-circuit voltage Voc, fill factor efficiency FF%, and cell efficiency η%). SCAPS-1D numerical simulation results show a significant effect of the absorber layer thickness on the device performance. An optimal absorber layer thickness has been achieved. The variation in CdS (buffer) layer thickness shows no observable effect in the values of FF% and Voc values, while a significant effect has been observed in the values of Jsc, and η%. There is no observable change in the device performance parameters with variation in the ITO (window) layer thickness. The Quantum efficiency percentage has been also affected both by the absorber and by the buffer layers thickness to a limit. The QE% achievement has been consistent with the optimal layer thickness.

ZnCl2 activated carbon (ZnCl2-AC, with specific surface area ~1480 m2/g) effectively adsorbs nitrate from water with uptake capacity (~5.5 mg/g) four-fold that for other commercial activated carbons (CACs). Kinetics show a small activation energy value (~7 kJ/mol) consistent with a diffusion-controlled process. This is further confirmed by intra-particle diffusion study. Negative thermodynamic parameters (ΔH° −13.859 kJ/mol, ΔS° −43.8 J/mol K, and ΔG° −0.808 kJ/mol) indicate spontaneous nitrate adsorption. The high specific surface area rationalizes the high uptake capacity for the ZnCl2-AC. A Langmuir type adsorption, is observed. ZnCl2-AC effectively adsorbs the nitrate from water, even at high concentrations, and brings the concentration to allowed maximum values. Despite these advantages, the ZnCl2-AC exhibits low desorption (~20%) of pre-adsorbed nitrate ions into concentrate solutions. Up to ~40% desorption is observed by grinding the pre-saturated ZnCl2-AC. Developing other methods to completely recover the adsorbed nitrate and the adsorbent for multiple use is needed.

Advanced oxidation process of the water organic contaminants is among the promising technologies for water purification. In this work, ZnO nanoparticles have been supported on natural clay particles. The prepared composite ZnO/Clay has been characterized by solid state electronic absorption spectra, X-ray diffraction and scanning electronic microscopy. It is used in photodegradation of aqueous 2-chlorophenole (2-CP) with direct solar radiation. As the catalyst surface charge and point of zero charge presumably influence adsorption uptake and photodegradation of the 2-CP molecules, these two properties have been studied here. For the composite, the optimal contaminant adsorption pH is 8.7, which is the optimal photodegradation value as well. The composite ZnO/Clay shows higher adsorption and photodegradation efficiency in 2-CP degradation compared to naked ZnO. This highlights the future practicality of using this composite catalyst under various natural conditions. Moreover, the ZnO/Clay can be easily recovered and reused for third cycle with no significant loss of efficiency. Complete mineralization of the 2-CP has been confirmed after enough time (2 h). This has been manifested by analysis for remaining organic materials inside the reaction mixture, using UV-visible spectra, high performance liquid chromatography and total organic carbon measurements.

This study aims to comparatively assess TiO2 and ZnO catalysts in photodegradation of aqueous acetaminophen solution. Commercial TiO2 (anatase and rutile phases), synthetic TiO2 (rutile) commercial ZnO (wurtzite), and synthetic ZnO (wurtzite) are all described; the synthetic ZnO and TiO2 were synthesized by thermal precipitation method. XRD, SEM, UV–vis spectroscopy, and BET/BJH were used for catalysts characterization. The photocatalytic experiments have been carried out using solar simulated radiation (0.0146 W/cm2). A 50 mL solution of an appropriate acetaminophen concentration was studied. The ZnO systems showed higher catalytic efficiency than the TiO2 counterparts. Among the TiO2 systems, the commercial anatase showed highest activity, followed by the synthetic system (rutile). Among the ZnO systems, the synthetic catalyst shows higher efficiency than the commercial counterpart. Based on its superior efficiency, the synthetic ZnO has been singled out for further investigation to find optimal working conditions. The pH plays a main role in photdegradation process, the synthetic ZnO photodegraded ∼97 % of acetaminophen at pH = 9 in 1 h of irradiation. The acetaminophen photodegradation in basic to neutral condition is better than acidic solutions. The synthetic ZnO particles completely mineralized acetaminophen within 120 min at pH = 7. This is confirmed by electronic absorption spectrophotometry, high-performance liquid chromatography and total organic carbon measurements. The photodegradation rate was increased with increasing the amount of loaded ZnO up to a steady-state limit of 0.1 g. Effects of different reaction parameters, on synthetic ZnO catalyst efficiency in acetaminophen photodegradation, are studied to find out the optimal conditions.

Waste CdSe film electrodes can be recycled into useful films without sacrificing their photoelectrochemical performance. Cd2+ aqueous ions have been recovered from waste CdSe electrodes by soaking in minimal amount of HCl (10.0 M) at 80 °C for 60 min. The Se2− ions, converted into H2Se(g) by the acid, have been trapped in basic NaOH solution for further use. The recovered Cd2+ ions have been used to deposit new (recycled) CdSe film electrodes onto fluorine doped tin oxide films (FTO/Glass) using aqueous Na2SeSO3 solutions by two methods. Electrochemical deposition (ECD) has been performed using applied potential (−1.0 V vs Ag/AgCl). Chemical bath deposition (CBD) has been performed in a basic medium at 70 °C. Both ECD and CBD recycled films have been prepared using recovered Cd2+ solutions, whereas fresh films have been prepared using fresh solutions. In both cases, the recycled CdSe films do not show any inferior characteristics to the freshly prepared counterparts. Effects of annealing at 150 °C and cooling rate on physical and photoelectrochemical (PEC) characteristics have been studied for different CdSe film electrodes. In both recycled and fresh systems, the CBD film electrodes exhibit enhanced uniformity, compactness and photo-electrochemical (PEC) performance by annealing. Upon annealing, the recycled and fresh ECD films exhibit less film uniformity and compactness, and consequently lower PEC performance. In ECD and CBD films, fast cooling is advantageous over slow cooling. Conversion efficiency values of ~8% are observed for the CBD recycled pristine films once carefully annealed and quickly cooled. This is higher than literature values for pristine CdSe (~5%), TiO2/CdS/CdSe (~4%) film electrodes, and resembles that for Tl/CdSe0.65Te0.35 (~8) multi-layer systems. The results show the feasibility of recycling waste CdSe film electrodes.

Throughout history, man used various natural materials as a remedy for treatment of various diseases and recently witnessing a vastly growing and renewed interest in herbal medicine globally. In Palestinian folk medicine Ephedra alata and Plumbago europaea used as diuretics and for treatment of hypertension. This study aimed to evaluate the diuretic and acute toxicity effects of the aqueous extracts for these two plants in mice following oral administration. Aqueous E. alata and P. europaea extracts (500 mg/kg) were administered orally to adult mice. Urine output and electrolytes were then measured after 4 h of administration and compared with those received furosemide 10 mg/kg (positive control group) and those received normal saline (negative control group). Significant diuresis was noted in those received the aqueous extract of E. alata (p, Moroccan Journal of Chemistry, Vol 6, No 4 (2018)

BACKGROUND The effect of storage time on the fluorescence emission intensity and physico-chemical properties of olive oil from the Palestinian cultivar Nabali Mohassan was investigated. Olive oil samples stored up to 7 years were obtained from different olive orchards in Palestine, where prolonged storage is still in use. RESULTS As a result of oxidation, all fluorescent minor compounds (tocopherols, chlorophylls, pheophytins and phenolic compounds) of olive oil significantly decreased as the storage time increased, whereas viscosity increased (P

Tetra(4-pyridyl)porphyrinato-manganese(III) (MnTPyP+) ions intercalated inside nano- and micro-size natural clay powders effectively catalyzed the hydrosilylation reaction of 1-octene and tri(ethoxy)silane under mild conditions. The results showed that the homogeneous MnTPyP+ ions catalyzed the reaction where both branched and linear products were observed. Intercalation significantly enhanced both catalyst activity and selectivity. Production of the linear tri(ethoxy)silyl-1-octane as sole product was confirmed by FT-IR and NMR spectra, in the case of the intercalated catalyst. The activity enhancement was more pronounced in the case of the nano-particle supported catalyst system, with turnover frequency (TF) values up to 1200 min−1 and 85% conversion observed in less than 20 min. The intercalated catalyst systems were easy to recover and were reused three times, while retaining up to 80% of their original activity. Effects of different reaction parameters on the initial reaction rate, such as clay particle size, solvent polarity, reactant concentration, catalyst loading and temperature, were investigated. A new plausible mechanism, with evidence and justifications, is proposed.

International audience; Electrodeposited CuSe film electrodes have been prepared onto FTO/glass by a facile method based on earlier methods described for other systems. The films were characterized, modified by annealing and further characterized. The films were then modified by coating with tetra(-4-pyridyl) pophyrinato-manganese (MnTPyP) complexes embedded inside commercial polyethylene (PE) matrices. The effects of modifications on different film properties, such as X-ray diffraction (XRD) patterns, surface morphology, photoluminescence (PL) spectra and electronic absorption spectra were investigated. Compared with other thin film electrode systems, very high photoelectrochemical (PEC) conversion efficiency values have been observed here. Pre-annealing the CuSe films at 150°C for 2 h, followed by attaching the MnTPyP/PE matrices remarkably enhanced their PEC characteristics. The conversion efficiency was significantly enhanced, from less than 1.0% to more than 15%. Fill factor (FF) was also enhanced from ∼30% to ∼80%. Values of open-circuit potential (VOC) and short-circuit current (JSC) were significantly enhanced. While annealing affects uniformity, particle inter-connection and surface texture of the CuSe films, the MnTPyP complex species behaves as an additional charge-transfer mediator across the film/electrolyte junction. Optimization of PEC characteristics, using different deposition times, different annealing temperatures, different annealing times and different redox couples, was also investigated.

This communication describes how olive solid wastes can be used to prepare activated carbon (AC), with soundly high surface areas, suitable to remove nitrite ions from water. Solid olive wastes, so called Jeft, separated as unwanted bi-products from olive oil mills, have been converted into charcoal. The charcoal was then physically and/or chemically activated using different compounds namely conc. H3PO4 or ZnCl2. Charcoal carbonization was performed under inert atmosphere to avoid loss of heated carbon by oxidation with air. Surface area measurements and SEM micrographs showed that activation using ZnCl2 yields AC with highest surface area and more porous surfaces. The ZnCl2-activated carbon was then used to remove nitrite ions from water by adsorption. Effects of different parameters on value of surface area and adsorption capacity of the AC were investigated. Commercial AC materials were used as reference for comparison. The AC showed higher adsorption capacity toward nitrite than other reported adsorbents. The results suggest that using 5 g of the ZnCl2-activated carbon per liter of heavily nitrite-contaminated water (50 ppm) may bring the contaminant concentration down to the WHO accepted concentration limits within 60 min. This work highlights the future feasibility of using olive waste as feed stocks to produce useful renewable materials while keeping in mind the wisdom "make wastes work in environmental protection".

Metal selenide poly-crystalline film electrodes with enhanced photo-electrochemical characteristics can be deposited by electrochemical then by chemical bath depositions onto glass/fluorine doped tinoxide substrates. The resulting film electrode shows the advantages of both electrochemical deposition (film uniformity and adhesion) and chemical bath deposition (suitable thickness). The two systems have been examined, and both showed enhanced conversion efficiency values. The copper selenide electrode showed ∼4.5% efficiency while the cadmium selenide showed ∼14% efficiency), both of which are much higher than earlier reported values for metal chalcogenide film electrodes. Other photo-electrochemical characteristics such as fill factor, film stability and short-circuit photocurrent density, have also been enhanced by the combined deposition. Moreover, the as-prepared films exhibited enhancement with no need for further treatment.

Pharmaceutical wastes are emerging as water contaminants. Like other organic contaminants, it is necessary to find safe and economic methods to remove them from the water. In this work, anthocyanin was used as a natural dye sensitizer for the wide band gap nanosize rutile TiO2. The TiO2/Anthocyanin particles were supported on activated carbon particle surfaces. The resulting composite, which was prepared and characterized by different methods, was then used as a catalyst in the photodegradation of phenazopyridine (a model pharmaceutical contaminant) under a solar simulated light. Depending on experimental conditions, up to 90% of the contaminant was mineralized leaving no new organic products in the reaction mixture. The results show the feasibility of using the activated carbon-supported TiO2/Anthocyanin photocatalyst for pharmaceutical contaminant removal in water. The natural dye anthocyanin readily sensitized the TiO2 to visible light. The unsupported TiO2, with its nanosize particles, was not easy to recover by simple separation methods, while the activated carbon-supported catalyst was easily isolated by decantation after reaction cessation. Moreover, the recovered AC/TiO2 catalyst could also be regenerated by adding fresh anthocyanin sensitizer after recovery for further reuse. Keeping the contaminant molecules closer to the catalytic sites by adsorption, the support also enhanced the efficiency of photocatalyst.

Pregnant and nursing women are at higher risk of zinc deficiency which can have detrimental consequences on health. We assessed blood zinc levels in 72 nursing women from the West Bank of Palestine and investigated the association between sociodemographic variables and blood zinc levels. Blood samples were analyzed for their zinc contents using graphite furnace atomic absorption spectrophotometry. Blood and data collection were performed between July and December 2016. The median blood zinc level was 4.53 mg/L (interquartile range of 0.38 mg/L). In unadjusted analyses, blood zinc levels were higher in nursing women who lived in cities (p-value

Natural waters are prone to pollution with organic contaminants, waste pharmaceuticals being an example. Pharmaceutical compounds are widely detected in different surface waters, such as lakes and rivers. Removal of such contaminants from water is therefore imperative. Different strategies are commonly followed such as adsorption, chlorination, ozonation, peroxidation and others. Each method has its shortcomings. Photodegradation of water organic contaminants by semiconductors is a safe and non-costly method. In photodegradation, the organic contaminant is completely mineralized with radiation and oxygen using stable semiconductor nanoparticles as photocatalysts. ZnO nanopowder is widely described for photodegradation processes. Due to its wide band gap (~3.2 eV) ZnO excitation is limited to UV radiation. Moreover, the nano-particle nature for the ZnO catalyst makes it difficult to recover and re-use after process completion. Supporting the ZnO nanoparticles onto stable solid material surfaces is one possible way out, and is studied here. Raw clay (kaolin) is described to support ZnO particles in photodegradation of a widely encountered pharmaceutical contaminant, tetracycline (TC). The results show the possibility of annealed ZnO/Kaolin to remove TC from water, firstly by adsorbing the contaminant then by photodegrading it into mineral species. The study shows that TC molecules pre-adsorbed onto ZnO/Kaolin were mineralized during photodegradation experiments. Complete mineralization of reacted contaminant molecules was confirmed by spectrophotometry, high performance liquid chromatography (HPLC) and total organic carbon (TOC) study. Control experiments with a cut-off filter (400 nm and shorter) confirmed the ability of the catalyst to function in the visible region, where contaminant molecules behave as sensitizers in the photodegradation process. Optimizing the efficiency of the ZnO catalyst in TC photodegradation processes by studying the effect of pH using the point of zero charge (pHPZC) concepts is achieved. Collectively, the results show the possibility to prepare an efficient recoverable ZnO/Kaolin catalyst, which can be sensitized with TC molecules themselves with optimal working pH range 6–9.

Photoelectrochemical (PEC) characteristics of CdTe film electrodes, known to have low conversion efficiency when used in their pristine form, can be significantly enhanced by carefully controlling their annealing temperature and cooling rate. Pristine CdTe films were electrodeposited onto FTO/Glass substrates which were used as anodes. To reach films with optimal characteristics, different applied preparation potentials were intentionally examined, namely 1.0, 1.1 and 1.2 V, vs. Ag/AgCl reference electrode (or 1.2, 1.3 and 1.4 V NHE, respectively) where the 1.1 V applied potential showed best PEC characteristics, and was thus followed unless otherwise stated. To study effect of annealing temperature, three temperatures (150, 200 and 250 oC) were attempted to enhance PEC characteristics of the deposited films. Effect of cooling rate, on PEC performance of pre-annealed films, was also studied using quenching and slow cooling. Films quenched from annealing at all temperatures showed lower PEC performance compared to non-annealed electrode. Film electrodes slowly cooled from 150 or 200 oC show enhanced PEC performance compared to quenched or non-annealed films. Film slowly cooled from 250 oC exhibited lower PEC performance than the quenched counterpart. Annealing at 250 oC lowered PEC for both quenching and slow cooling. As a low band gap semiconductor film electrode, it is recommended to slowly cool CdTe from low annealing temperatures, and to quickly cool them from relatively higher annealing temperature. The annealing temperature and cooling rate effects on CdTe film PEC performance are attributed to their effects on other physical characteristics, namely crystallinity, morphology and chemical composition. The optimal conversion efficiency (6.9%) was observed for film deposited at 1.1 V applied potential when annealed at 200 oC and slowly cooled to room temperature.

International audience; Polycrystalline CdSe films have been deposited onto fluorine doped tin oxide (FTO/glass) substrates by three different techniques, electrochemical deposition (ECD), chemical bath deposition (CBD) and, for the first time, combined ECD and CBD (ECD/CBD). The films were comparatively characterized by photoluminescence spectra (PL), electronic absorption spectra, scanning electron microscopy (SEM) and X-ray diffraction (XRD). The SEM micrographs show that the films involved rod shaped agglomerates with various lengths and widths. XRD patterns show that the three systems involved nano-sized CdSe particles with cubic type crystals. Based on Scherrer's equation, the ECD film showed larger particle size than the CBD film, while the ECD/CBD film showed largest particles among the series. Similarly, the band gap values varied for different films as CBD > ECD > ECD/CBD. Photo-electrochemical (PEC) characteristics, including photo-current density vs. voltage (J-V) plots, conversion efficiency (ƞ), fill factor (FF) and stability were all studied for different film electrodes. The films exhibited n-type behaviors with direct band gaps. The new ECD/CBD-CdSe electrode exhibited higher conversion efficiency (ƞ% ~ 4.40) than other counterparts. The results show the added value of combining ECD and CBD methods in enhancing PEC characteristics of CdSe film electrodes, even with no additional treatment.

In search for safe techniques to manage waste pharmaceutical compounds drained in water, solar-driven degradation of phenazopyridine (a model drug) was investigated in aqueous media using different ZnO-based catalyst systems. Naked ZnO, CdS-sensitized ZnO (ZnO/CdS) and activated carbon-supported ZnO (AC/ZnO) have been studied. Both naked ZnO and AC/ZnO were highly efficient in mineralizing phenazopyridine, reaching complete removal in ∼50 min, with AC/ZnO having the higher edge. The ZnO/CdS system showed lower efficiency, due to screening of light by CdS. Moreover, the tendency of CdS to leach out Cd 2+ ions discouraged the use of CdS as sensitizer in this work. In both ZnO and AC/ZnO systems, the photo-degradation reaction was induced by the UV tail of the solar light. The visible region, with wavelength longer than 400 nm, failed to induce photo-degradation. The reaction was faster with higher catalyst loading, until a maximum efficiency was reached at a certain concentration. The rate of reaction increased with higher drug concentrations up to a certain limit. The effect of pH value was studied, and the catalysts showed highest efficiencies at pH close to 7. Stability of ZnO to degradation was studied. Both catalyst systems showed lowered efficiencies on recovery and reuse. The results suggest that complete mineralization of waste drugs, commonly dumped in sewage water, with direct solar light is a potentially feasible strategy using the AC/ZnO catalyst.