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Hydrogen peroxide (H2O2) is a valuable clean chemical, which is widely applied in modern industrial production. In the past few decades, H2O2 has been mainly produced industrially by the anthraquinone method, but the process is complicated and energy consuming, which is only economical for large-scale production and is harmful to the environment. The direct synthesis of H2O2 is considered a promising process to replace the anthraquinone method with high atomic economy, no hazardous by-products, and convenient operation, which has attracted much attention. In this review, we systematically present the recent advances in tuning the microenvironment of Pd-based catalysts for enhancing the performance of the direct synthesis of H2O2, including the modulation of active sites and support, from the viewpoint of the reaction mechanism. Finally, a summary and perspective on the most pressing issues and associated untapped research prospects with the direct synthesis of H2O2 are discussed. The purpose of this review is to provide in-depth insights and guidelines to promote the development of novel catalysts for the direct synthesis of H2O2. [ABSTRACT FROM AUTHOR]

Wide‐bandgap perovskite solar cells (WBG‐PSCs) are pivotal in achieving high‐performance tandem solar cells. However, their power conversion efficiency (PCE) is limited by the losses from the interfacial charge transfer barrier and nonradiative recombination. In this investigation, 1,4‐bis(aminomethyl)benzene (PDMA) is employed as a defect passivator for fabricating methylammonium (MA)‐free perovskite solar cells (PSCs), thus effectively mitigating nonradiative recombination losses of charge carriers. Meanwhile, PDMA molecules chemically rinse the perovskite film to create a grooved surface, leading to the increase of contact area between the perovskite and electron transport layer to further improve the interfacial charge transfer. As a result, the PSCs based on these surface‐passivated and chemically cleaned perovskite films present a champion PCE of 21.23% (Eg = 1.68 eV) compared to the control devices with a PCE of 18.23%, while maintaining over 80% efficiency after 800 h storage in ambient air. This study presents a highly effective approach for one‐step passivation and chemical cleaning of wide‐bandgap perovskite for efficient and stable solar cells, offering valuable insights for future research in this field. [ABSTRACT FROM AUTHOR]

The diffusion-bonding technique has been utilized to join various Al alloys (AA1060, AA2024, AA3003) to Cu for bimetallic anode application. This process aims to achieve robust metallic continuity to facilitate electron transfer, while carefully managing the growth of the intermetallic layer at the bonding interface. This control preserves the active volume of aluminum and prevents excessive brittleness of the anode. Optimization efforts have focused on different pressures, surface treatments of parent materials, and bonding parameters (temperature 450–500 °C and time 5–60 min). The optimal conditions identified include low bonding pressures (8 MPa), surface treatment involving polishing followed by chemical cleaning of the surfaces to be bonded, and energetic bonding conditions tailored to each specific aluminum alloy. Preliminary electrochemical characterization via cyclic voltammetry (CV) tests has demonstrated high reversibility intercalation/deintercalation reactions for up to seven cycles. The presence of the different alloying elements appears to contribute significantly to maintaining the high intercalation/deintercalation reaction reversibility without considerable modification of the reaction potentials. This effect may be attributed to alloying elements effectively reducing the overall alloy volume expansion, potentially forming highly reversible ternary/quaternary active phases, and creating a porous reaction layer on the exposed aluminum surface. These factors along with the influence of the Cu parent material collectively reduce the stress during volume expansion, which is the responsible phenomenon of the anode degradation in common Al anodes. [ABSTRACT FROM AUTHOR]

Objective: This research endeavors to scrutinize the influence of attachment systems and denture cleaning methodologies on microbial biomass and composition within the realm of implant-supported overdentures, a crucial consideration for patients with dentition defects necessitating such prosthetic solutions. Subjects and methods: Employing five polymethyl methacrylate specimens designed to emulate the fitting surfaces of traditional dentures and implant-supported overdentures. Following the polishing of each specimen and the quantification of its roughness, co-cultivation with three distinct microbial strains ensued, culminating in ultrasonic cleaning in water. The bar-clip group, differentiated by the depth of attachment, underwent cleaning employing four diverse methods. Biomass quantities were meticulously recorded both pre and post cleaning interventions, with subsequent data analysis via t-testing and one-way ANOVA, maintaining a significance level of α = 0.05. Results: The bar-clip groups demonstrated an elevated degree of microbial adhesion, with the deeper locator group exhibiting heightened biomass residue post-cleaning, indicative of increased cleaning complexity. Ultrasonic cleaning predominantly targeted biofilm and deceased bacteria, whereas chemical cleaners primarily reduced the quantity of viable bacteria. The synergistic application of ultrasonics and chemical cleaning treatments yielded the minimal biomass residue. Conclusion: In contemplating the utilization of dentures milled by dental computer-aided design/manufacturing systems, meticulous pre-use surface polishing is imperative. The extent of biofilm adhesion correlates with the chosen attachment system. This study advocates for the incorporation of ultrasonic cleaning in conjunction with chemical cleaning solutions to optimize the removal of biofilm and live cellular entities in the context of implant-supported overdentures. [ABSTRACT FROM AUTHOR]

The FCC unit is closely related to its upstream and downstream units, especially for single series refineries, the change of the working condition of the upstream unit will have a significant impact on the production and operation of the downstream unit. During the catalyst replacement period of the residue hydrogenation unit, the FCC unit blended vacuum residue, resulting in severe deterioration of the properties of the FCC feedstock. The increase in vanadium content in the feedstock led to a decrease in the activity of the equilibrium catalyst and an increase in the olefin content of the FCC gasoline, causing rapid coking of heat exchanger group E101 in the S Zorb unit and affecting its operation. Therefore, during the catalyst replacement period of the residue hydrogenation unit, it is recommended to purchase light paraffin-base crude oil with low sulfur and metal content in advance, in order to alleviate the vanadium poisoning of the FCC unit catalyst; try to increase the catalyst consumption of the FCC unit to over 2.0 kg/t to prevent excessive vanadium content of the equilibrium catalyst; if E101 is rapidly coking and has caused excessive pressure drop, chemical cleaning can be used to clean the coking in the E101 tube pass. [ABSTRACT FROM AUTHOR]

This study delves into the impact of aging on PVDF membranes due to exposure to various NaOCl-based household bleach products, namely Bayclin, Proclin, and Soclin, over different durations (0, 1, 3, and 5 days). The primary objective is to assess the influence of household bleaches as cleaning agents on the stability and durability of PVDF membranes. Our findings underscore that prolonged exposure to NaOCl-based cleaning agents induces changes in pore structure, morphology, mechanical strength, and flux performance of the membranes owing to oxidation by hypochlorite. However, these alterations are mitigated when using household cleaning agents, particularly Soclin and Proclin. For instance, after 5 days, membranes aged with NaOCl exhibited an enlargement of pore size up to 0.2 mm, whereas those aged with Soclin (MS) and Proclin (MP) only experienced an enlargement to 0.12 mm from the original pore size of 0.05 mm. This increase in pore size is undesirable as it adversely affects the selectivity performance of the membranes. Additionally, the hydrophilicity of membranes was found to be better maintained when aged with household products compared to pure NaOCl, as evidenced by the higher water contact angle observed in MP and MS membranes. Furthermore, the flux recovery ratio (FRR) exhibited an upward trend with prolonged aging duration, with Bayclin showing the highest FRR of 180 %, closely to that of pure NaOCl at nearly 190 %, among the other two products. This significant increase in FRR is undesirable as it results from the enlargement of pore morphology caused by damage from exposure to hypochlorites which is stronger in the chemical-grade NaOCl compared to the household bleach products. In summary, this study highlights that household bleaches, especially Soclin and Proclin, present a promising option in terms of stability for prolonged use. These results are crucial for identifying chemicals that are not only more efficient in the cleaning process but also less damaging to the membranes with good stability in long-term use.

This study aimed to prevent health damage caused by chemical exposure among cleaning workers who use cleaning agents and disinfectants in facility management and kitchen areas. We analyzed 5 years of measurement data (2016–2020) for cleaning workers across various industries in Korea, and conducted an exposure survey and health risk assessment for the two most frequently measured substances (i.e., 2-butoxyethanol and sodium hydroxide) and representative substances generated by their combined use (i.e., chlorine and chloroform). The findings indicate that when chlorine was generated by mixing hypochlorite-based disinfectants (e.g., bleach) with acidic cleaners containing substances such as nitric, hydrochloric, or citric acid, the risk index for chlorine gas (based on the 95th percentile exposure values) was 5.65 in the facility management cleaning industry, exceeding the acceptable threshold of 1. Because of the high usage and exposure frequency of cleaning and disinfecting agents and the common practice of mixing multiple products to enhance cleaning efficacy, it is necessary to manage hazardous risk factors by providing education on appropriate working methods, supplying personal protective equipment, and installing ventilation systems for these workers. Further research on the health risk assessment of combined chemical use is needed. [ABSTRACT FROM AUTHOR]

Copyright of Urban Geology is the property of Urban Geology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Fouling of heat exchangers and refining equipment by crude oil deposits is a chronic operating problem. In general, many such deposits are narrowly defined as coke fouling, for which the prescribed cleaning has traditionally been high-pressure water blasting. The results for this type of cleaning are mixed at best. Heat exchangers are often returned to service at conditions less than 85% clean performance, driving the need for more efficient cleaning regimens. A detailed characterization of 62 field-based crude oil fouling deposits from hydrocarbon process units was presented by the authors in 2019. This paper demonstrated that such deposits are exceptionally complex, resulting in the introduction of the Coke Spectrum. Here, these deposits are revisited, and chemical cleaning methods are applied. Chemical cleaning encompasses a variety of applications. Circulation, ultrasonic immersion, and clean-in-place techniques were reviewed on laboratory-scale samples to determine what chemical cleaning agents are most effective toward the various categories of foulant making up the Coke Spectrum. Combination techniques which employ both chemical and mechanical applications simultaneously or in sequence are considered in depth. The correlation between chemical composition and the effectiveness of the cleaning method is explored with considerations for scaling from laboratory to industrial application. [ABSTRACT FROM AUTHOR]

Hybrid water electrolysis (HWE) is a promising pathway for the simultaneous production of high-value chemicals and clean H2 fuel. Unlike conventional electrochemical water splitting, which relies on the oxygen evolution reaction (OER), HWE involves the anodic oxidation reaction (AOR). The AORs facilitate the conversion of organic or inorganic compounds at the anode into valuable chemicals, while the cathode carries out the hydrogen evolution reaction (HER) to produce H2. Recent literature has witnessed a surge in papers investigating various AORs with organic and inorganic substrates using a series of transition metal-based catalysts. Over the past two decades, metal–organic frameworks (MOFs) have garnered significant attention for their exceptional performance in electrochemical water splitting. These catalysts possess distinct attributes such as highly porous architectures, customizable morphologies, open facets, high electrochemical surface areas, improved electron transport, and accessible catalytic sites. While MOFs have demonstrated efficiency in electrochemical water splitting, their application in hybrid water electrolysis has only recently been explored. In recent years, a series of articles have been published; yet there is no comprehensive article summarizing MOFs for hybrid water electrolysis. This article aims to fill this gap by delving into the recent progress in MOFs specifically tailored for hybrid water electrolysis. In this article, we systematically discuss the structure–property–performance relationships of various MOFs utilized in hybrid water electrolysis, supported by pioneering examples. We explore how the structure, morphology, and electronic properties of MOFs impact their performance in hybrid water electrolysis, with particular emphasis on value-added chemical generation, H2 production, potential improvement, conversion efficiency, selectivity, faradaic efficiency, and their potential for industrial-scale applications. Furthermore, we address future advancements and challenges in this field, providing insights into the prospects and challenges associated with the continued development and deployment of MOFs for hybrid water electrolysis. [ABSTRACT FROM AUTHOR]

Rubber tire mold fouling is a severe problem leading to mold surface corrosion, tire defects, and extra energy consumption. Traditional mechanical and chemical cleaning is inefficient and induces mold surface damage. Low surface energy organic coating displays antiadhesive behavior but is susceptible to wear. Here, we develop a bioinspired Co-CeO2/MoS2 coating with effective mechanical robustness, corrosion resistance, and antifouling behavior by leveraging a slippery liquid-infused surface (SLIPS) strategy. The micro-nanostructure of the coating serves as mechanical stability and anticorrosion skeleton with the infused lubricant acting as a slippery antifouling surface. The variation of microstructure, mechanical strength, corrosion resistance, and antifouling behavior of the coating with individual and synergistic addition of CeO2 and MoS2 is systematically characterized. The slippery Co-CeO2/MoS2 coating shows excellent mechanical stiffness, corrosion resistance, and antifouling performances in rubber vulcanization conditions. [ABSTRACT FROM AUTHOR]

This study synthesized three MoS₂ morphologies—nanospheres, nanoplatelets, and nanosheets—under varied conditions and incorporated them into chitosan membranes. TEM confirmed unique morphologies and crystallinity. Clean water flux showed that the nanoplatelet (P-CM) membrane had the highest flux due to higher porosity. The P-CM membrane excelled in removing Mn²⁺ and Zn²⁺ ions, achieving 93.0 ± 0.5% and 90.4 ± 1.5% removal, outperforming membranes with nanospheres (S-CM) and nanosheets (T-CM). Its superior performance is attributed to thicker nanoplatelets forming more water channels. The MoS₂'s tri-layered structure generated reactive oxygen species (ROS) via H₂O₂ catalysis, contributing to enhanced heavy metal removal. These adsorptive-catalytic membranes combine adsorption with catalytic decomposition of heavy metals, highlighting the work's novelty and superior performance. The membranes demonstrated excellent flux recovery and reusability (96.0 ± 0.5% for P-CM) after chemical cleaning. The findings emphasize the impact of nanomaterial morphologies on membrane performance in water treatment and environmental remediation. [ABSTRACT FROM AUTHOR]

Plasma-activated water (PAW) can be used as an alternative to reduce the consumption of cleaning chemicals and cleaning time in the cleaning of facilities for the processing of cosmetics and other hygiene-critical products. PAW shows a comparable cleaning effect to conventional cleaning agents and can also be used to clean product residues from the cosmetics industry. PAW offers potential for more efficient cleaning processes and saving process steps. It can also provide ecological benefits in disposal. Studies have shown that PAW is similarly effective as conventional cleaning agents and offers the possibility to combine cleaning and disinfection in one step. PAW can be stored for longer periods without losing its effectiveness, leading to lower costs and easier disposal. Future investigations on the concentration of important reactive species in PAW and their behavior during storage are recommended. [Extracted from the article]

This article explores the issue of membrane fouling in various industries and discusses strategies to reduce and delay fouling. Researchers are looking to nature for inspiration, using biomimicry and natural materials to develop innovative solutions. Examples include using superhydrophilic surfaces inspired by cell membranes to repel organic foulants, using bacterial cellulose membranes for oil-water separations, and coating membranes with liquids to control pore openings. The article also discusses methods and technologies used in water treatment processes, such as using polydopamine as a connective tissue for a deeper clean and utilizing cell membrane mimetic coatings to separate oil and water mixtures. The findings have practical implications for improving water treatment processes and reducing waste. [Extracted from the article]

The main challenge with membrane bioreactors is fouling, which leads to decreased flux performance and a shortened membrane lifespan. This study aims to provide a solution for the flux recovery and removal of irreversible fouling on Polyvinylidene Fluoride (PVDF) membranes without damaging their structure using sulfate radicals. Sulfate radicals are formed via peroxodisulfate precursors that are activated by Fe2+. The membrane flux recovery and irreversible fouling ratio were 88.45-99.04% and 11.60-0.96%, respectively, at operating temperatures of 298-308 K. The PVDF membrane has been tested for microfiltration and washed up to 6 times per cycle. The mechanical properties, XRD, SEM-EDX, and ATR-FTIR characterization of the PVDF membrane after washing with PDS/Fe2+ did not show a negative effect on the PVDF structure. Additionally, the results of the kinetic and thermodynamic studies showed that washing with PDS/Fe2+ inhibited the formation of fouling particles on the membrane surface. Based on this study, sulfate radical oxidants with PDS precursors activated by Fe2+ can be applied as cleaning chemicals for PVDF membranes without damaging their structures.

An innovative green organogel was designed to simultaneously tackle inorganic compounds (i.e., iron corrosion) and organic substances (i.e., acrylic coatings) as undesired materials possibly present on the surface of altered indoor metal artworks. Poly-3-hydroxybutyrate (PHB), ethyl lactate (EL), and deferoxamine B (DFO) were employed in the formulation as thickening agent, organic solvent, and complexing agent, respectively, aiming to propose a sustainable and less harmful chemical cleaning method for metal care. The components were selected because they are bio-sourced, renewable, biodegradable, and non- or low-toxic materials. A multi-modal protocol of analysis was carried out to characterise the newly designed PHB-EL-DFO organogel. The cleaning performance of the novel formulation was assessed on mild steel mock-ups presenting both corrosion and organic coating to be removed. The conducted multi-analytical approach verified that the PHB-EL-DFO gel was able to tackle the two undesired materials simultaneously in an adjustable and easy-to-use way thanks to a modular application. [ABSTRACT FROM AUTHOR]

In an effort to reduce the occurrence of chlorine derived residues such as chlorate and trichloromethane (TCM) in milk and ultimately in dairy products, 'chlorine-free' cleaning of milking equipment became compulsory in the Republic of Ireland (ROI) from January 2021. While data exists on TCM levels in bulk tank milk, little is known about the prominence and typical levels (mg/kg) of chlorate residue in bulk tank milk. To address this, 3625 bulk milk samples were collected from six milk processors and were analysed for chlorate and TCM residues across 2020 and 2021, with 2020 representing a period before chlorine-free cleaning was introduced and 2021 being the period after chlorine removal. In 2020, 15% of the samples analysed had detectable levels of chlorate (0.0020–1.6 mg/kg), but this reduced to 8% in 2021 (0.0020–3.9 mg/kg), following the introduction of 'chlorine-free' cleaning. Chlorate and TCM residues have not been totally eliminated because sources of residue other than cleaning chemicals exist, i.e., chlorinated water. [ABSTRACT FROM AUTHOR]

This study aims to explore the performance of suppliers in the tourism and traveling sector. Therefore, we designed a case study in a cruise hotel and developed a team of experts to evaluate the existing suppliers. To rate suppliers, a grey multi-criteria decision-making (G-MCDM) platform is built to encounter the best-performing suppliers. CRITIC (CRiteria Importance Through Inter-criteria Correlation) and CoCoSo (combined compromise solution) methods are used. The results demonstrate that Food suppliers and Interior design maintenance services are selected as the best-performing actors in supply chain while suppliers for chemical cleaning materials are is rated as the worst. [ABSTRACT FROM AUTHOR]

While depolarization of the neuronal membrane is known to evoke the neurotransmitter release from synaptic vesicles, hyperpolarization is regarded as a resting state of chemical neurotransmission. Here, we report that hyperpolarizing neurons can actively signal neural information by employing undocked hemichannels. We show that UNC-7, a member of the innexin family in Caenorhabditis elegans, functions as a hemichannel in thermosensory neurons and transmits temperature information from the thermosensory neurons to their postsynaptic interneurons. By monitoring neural activities in freely behaving animals, we find that hyperpolarizing thermosensory neurons inhibit the activity of the interneurons and that UNC-7 hemichannels regulate this process. UNC-7 is required to control thermotaxis behavior and functions independently of synaptic vesicle exocytosis. Our findings suggest that innexin hemichannels mediate neurotransmission from hyperpolarizing neurons in a manner that is distinct from the synaptic transmission, expanding the way of neural circuitry operations. [ABSTRACT FROM AUTHOR]

The single-pass transmembrane protein Stromal Interaction Molecule 1 (STIM1), located in the endoplasmic reticulum (ER) membrane, possesses two main functions: It senses the ER-Ca2+ concentration and directly binds to the store-operated Ca2+ channel Orai1 for its activation when Ca2+ recedes. At high resting ER-Ca2+ concentration, the ER-luminal STIM1 domain is kept monomeric but undergoes di/multimerization once stores are depleted. Luminal STIM1 multimerization is essential to unleash the STIM C-terminal binding site for Orai1 channels. However, structural basis of the luminal association sites has so far been elusive. Here, we employed molecular dynamics (MD) simulations and identified two essential di/multimerization segments, the a7 and the adjacent region near the a9-helix in the sterile alpha motif (SAM) domain. Based on MD results, we targeted the two STIM1 SAM domains by engineering point mutations. These mutations interfered with higher-order multimerization of ER-luminal fragments in biochemical assays and puncta formation in live-cell experiments upon Ca2+ store depletion. The STIM1 multimerization impeded mutants significantly reduced Ca2+ entry via Orai1, decreasing the Ca2+ oscillation frequency as well as store-operated Ca2+ entry. Combination of the ER-luminal STIM1 multimerization mutations with gain of function mutations and coexpression of Orai1 partially ameliorated functional defects. Our data point to a hydrophobicity-driven binding within the ER-luminal STIM1 multimer that needs to switch between resting monomeric and activated multimeric state. Altogether, these data reveal that interactions between SAM domains of STIM1 monomers are critical for multimerization and activation of the protein. [ABSTRACT FROM AUTHOR]

This study seeks to increase the antifouling properties of fluorinated polyvinylidene (PVDF) membranes through the synergistic application of plasma treatment and polymer deposition, employing polymerizations of polyvinylpyrrolidone (PVP) and polyethyleneimine (PEI). The results show remarkable success in modifications, presenting exceptional performance. Two distinct surface modification methods, plasma treatment and polymer deposition, were used to improve the antifouling properties and filtration performance of PVDF membranes. The plasma used was a discharge dielectric barrier using ambient air as gas, and hydrophilic polymers, PVP, and PEI. The results outlined changes in membrane roughness with a significant roughness reduction of up to 43% evident based on topographic and morphological analyses. Hydraulic permeability analysis revealed a substantial 35‐fold increase, indicating a notable improvement in performance. All treated membranes exhibited higher water affinity and superior performance during 12‐h ultrafiltration compared to their untreated counterparts. After chemical cleaning, water flux recovery exceeded 85% for all treated membranes, indicating the inherent antifouling properties of the surface. [ABSTRACT FROM AUTHOR]

The method of chemical cleaning of the surface of blades of gas turbine units in a solution of orthophosphoric and sulfuric acids using a purpose-designed closed-type autoclave microwave system "Mars 5" and ultrasonic exposure in distilled water is described. The two-stage cleaning involves the chemical action of the acid solution in the autoclave and ultrasonic cleaning in the stage of washing. The effect of acid solutions of various concentrations on the degree of surface cleaning from metal oxides and microcracks in the gas turbine blades is studied. It is shown that when the samples of gas turbine blades are treated in the "Mars 5" autoclave with a solution of acids and with ultrasound in the washing stage, the residual oxygen content reflecting the presence of oxides on the surface of the samples is less than 1%. [ABSTRACT FROM AUTHOR]

Biological traces inside firearm barrels were observed as a result of contact shots to the head. The present study was conducted to investigate the influence of the muzzle to target distance on staining inside the anterior and posterior part of firearm barrels. Ninety-nine shots were fired to so-called reference cubes (10% gelatine, 12 cm edge length, embedded paint-blood-pad) using three current handguns. Shot range was varied from contact to 50 cm distance. High-speed cameras recorded external backspatter. Endoscopic examination assessed visible staining along the barrel. Each two swabbings were gathered from the anterior and the posterior part of the barrel. The first swabs were submitted to quantitative PCR, the second ones to DNA-RNA-co-extraction. Thorough mechanical and chemical cleaning was performed to avoid any contamination which was controlled by negative zero swabs after each cleaning. In single shots up to 50 cm distance, minimal, but DNA-positive sporadic traces were detected inside the barrel in vicinity of the muzzle. Visible complex staining varying in extent was observed in the anterior barrel part for 10 cm or less distance in dependence of the calibre. The posterior part showed detectable traces only after close range shots (< 5 cm). Generally staining inside the barrel decreased from the muzzle to the rear end, which correlated with the yield of DNA. Some contact shots did not cause any staining in the posterior part of the barrel despite massive external backspatter. Blood-specific miRNA was primarily found where DNA was detected. This experience encourages to take a second swab for RNA analysis. The amount of nucleic acids in the barrel at varying muzzle to target distances is subject to large variations between individual shots and therefore appears not suitable for a reliable determination of the shot distance in a particular case on its own. Instead, shot range estimation should also take into account morphology and distribution of traces inside the barrel. [ABSTRACT FROM AUTHOR]

This paper aims to document the conservation processes of a polychrome wooden coffin in the Dahshur archaeological area dating back to the late period. The exterior part of the coffin is decorated with a painted layer. Visual observation, 2D Program, and Optical Microscopy (OM) were used. wood identification. The coffin was in a bad condition. It was covered with a thick layer of dust, losing parts of the painted and gesso layers, as well as other parts of these layers, were lost. Some parts were missing from the head area of the lid coffin. The conservation processes of the wooden coffin included mechanical and chemical cleaning, reattachment of the separated parts of the ground layer and painted layers, filling the edge of the painted layer, and consolidating the painted layer. The conservation process included mechanical cleaning using soft brushes, chemical cleaning using ethyl alcohol and distilled water for painting, stabilization of the separated gesso layer using Paraloid B72, filling cracks of the gesso layers using glass microballoon with Paraloid B72 and consolidating the painted layer with calcium oxide nanoparticles with Klucel G (hydroxypropyl cellulose) 0. 5% [ABSTRACT FROM AUTHOR]

The purpose of this study was the chemical characterization and conservation of the Bes pottery jar. Pottery jars were important in Egypt from prehistoric times until the end of late history; they had their ideological symbolism and important role in daily life. "Bes" jar is a kind of healing jar, which was known and spread during the end of the New Kingdom and Late Period of ancient Egypt. AutoCAD, digital microscope, and polarized microscope (PLM) were used to clarify the deterioration state of the pottery jar. The XRD method was used to investigate the mineralogical composition of the pottery jar. Besides, the pottery's internal morphology and chemical composition were studied using scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX). The examination revealed that the selected pottery jar exhibited numerous cracks, dust accumulation, salt crystallization, and black spots. PLM showed the presence of several minerals, such as calcite, quartz, biotite, and plagioclase. SEM-EDX analysis revealed high calcium oxide concentrations due to the use of calcium carbonate in the slip layer, besides chloride salts. XRD analysis indicated that quartz was the predominant mineral in all the samples. Additionally, calcite, diopside, anorthite, halite, and dolomite were also detected in varying proportions. The pottery jar underwent various treatments, including mechanical and chemical cleaning. In addition, dental gypsum and grog were used in the completion process. Furthermore, the paraloid B-72 was used to achieve the consolidation process. [ABSTRACT FROM AUTHOR]

Biogeochemical reactions modulate the chemical composition of the oceans and atmosphere, providing feedbacks that sustain planetary habitability over geological time. Here, we mathematically evaluate a suite of biogeochemical processes to identify combinations of reactions that stabilize atmospheric carbon dioxide by balancing fluxes of chemical species among the ocean, atmosphere, and geosphere. Unlike prior modeling efforts, this approach does not prescribe functional relationships between the rates of biogeochemical processes and environmental conditions. Our agnostic framework generates three types of stable reaction combinations: closed sets, where sources and sinks mutually cancel for all chemical reservoirs; exchange sets, where constant ocean-atmosphere conditions are maintained through the growth or destruction of crustal reservoirs; and open sets, where balance in alkalinity and carbon fluxes is accommodated by changes in other chemical components of seawater or the atmosphere. These three modes of operation have different characteristic timescales and may leave distinct evidence in the rock record. To provide a practical example of this theoretical framework, we applied the model to recast existing hypotheses for Cenozoic climate change based on feedbacks or shared forcing mechanisms. Overall, this work provides a systematic and simplified conceptual framework for understanding the function and evolution of global biogeochemical cycles. [ABSTRACT FROM AUTHOR]

Water--energy sustainability will depend upon the rapid development of advanced pressure-driven separation membranes. Although energy-efficient, water-treatment membranes are constrained by ubiquitous fouling, which may be alleviated by engineering self-cleaning membrane interfaces. In this study, a metal-polyphenol network was designed to direct the armorization of catalytic nanofilms (ca. 18 nm) on inert polymeric membranes. The chelation-directed mineralized coating exhibits high polarity, super-hydrophilicity, and ultralow adhesion to crude oil, enabling cyclable crude oil-in-water emulsion separation. The in-place flux recovery rate exceeded 99.9%, alleviating the need for traditional ex situ cleaning. The chelation-directed nanoarmored membrane exhibited 48-fold and 6.8-fold figures of merit for in-place self-cleaning regeneration compared to the control membrane and simple hydraulic cleaning, respectively. Precursor interaction mechanisms were identified by density functional theory calculations. Chelation-directed armorization offers promise for sustainable applications in catalysis, biomedicine, environmental remediation, and beyond. [ABSTRACT FROM AUTHOR]

• Analysis of the 1064 nm laser cleaning potential of the medieval iron nail presented. • Good state of the nail core under the corrosion layer shown by the radiography method. • Approximate optimal range of 1064 nm laser parameters determined for safe cleaning. • Combination of mechanical and chemical cleaning methods with laser cleaning necessary. In this paper, the state of an archaeological artefact (iron nail) originating from the Studenica Monastery (Serbia) has been presented as well as the possibility of laser cleaning its corrosion layers. To determine the presence of cracks and other defects in the sample, the digital radiographic method was used. The composition of the artefact was analysed by X-ray Fluorescence Spectrometry (XRF) and energy-dispersive X-ray Spectroscopy (EDX). The corrosion products were investigated by X-ray diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Raman Spectroscopy, and EDX microanalysis. The Nd:YAG laser was used for corrosion cleaning. The morphological modification of the surfaces cleaned by laser was analysed with optical and scanning electron microscopy (SEM). The test results showed that the cleaning of thick corrosion deposits with a laser is difficult and very expensive. Therefore, it is necessary to combine mechanical or chemical methods with lasers. [ABSTRACT FROM AUTHOR]

Copyright of Corrosion & Protection in Petrochemical Industry is the property of Corrosion & Protection in Petrochemical Industry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We report on the collective response of an assembly of chemomechanical BelousovZhabotinsky (BZ) hydrogel beads. We first demonstrate that a single isolated spherical BZ hydrogel bead with a radius below a critical value does not oscillate, whereas an assembly of the same BZ hydrogel beads presents chemical oscillation. A BZ chemical model with an additional flux of chemicals out of the BZ hydrogel captures the experimentally observed transition from oxidized nonoscillating to oscillating BZ hydrogels and shows this transition is due to a flux of inhibitors out of the BZ hydrogel. The model also captures the role of neighboring BZ hydrogel beads in decreasing the critical size for an assembly of BZ hydrogel beads to oscillate. We finally leverage the quorum sensing behavior of the collective to trigger their chemomechanical oscillation and discuss how this collective effect can be used to enhance the oscillatory strain of these active BZ hydrogels. These findings could help guide the eventual fabrication of a swarm of autonomous, communicating, and motile hydrogels. [ABSTRACT FROM AUTHOR]

In this study, 31 household spray-type cleaning products from 10 categories were examined to identify the substances contained in these products and evaluate their resulting toxicities. After substance detection via LC-QTOF-MS, suspect and non-target screenings were performed using UNIFI software. A total of 48 substances were identified during suspect screening. Among them, surfactant (freq. 22/31(71.0%)), plasticizer (freq. 23/31(74.2%)), antioxidant (freq. 20/31(64.5%)) were detected with high frequencies. Among the 48 compounds, tributyl citrate acetate was the most frequently detected (frequency 13/31, 41.9%). In addition, 51 substances were identified via non-target analysis. Among them, oleamide, a type of surfactant, showed a high frequency of detection (22/31(71.0%)). The toxicities of the 98 substances (suspect: 47 (except for confidence level 5) and non-target: 51) identified were evaluated using the European Chemicals Agency (ECHA) database and Toxtree. Among them, 20 substances were classified as a substance of caution. The risk assessment for 3 substances identified with references standards was also performed. The suspect and non-target screening technique proved to be a useful method that can be applied when there are many non-specific chemicals and their components in the consumer products are not well known. [ABSTRACT FROM AUTHOR]

The commonly used polymeric disinfectants, didecyldimethylammonium chloride (DDAC) and polyethylene glycol monoalkyl ether (GEN) can drift with water vapor and aerosols, although they are not volatile. When they present in aerosols, their amines have justified to irritate the respiratory organs of humans. But, when they are not in breading air they stay on surfaces due to absorption and accumulation when temperature and moisture of the environment are low. The paper presents a new approach to determine disinfectants in alkaline tetraborate solution using capillary electrophoresis with direct UV detection. DDAC and GEN were investigated to move from surfaces to aerosol. The studied compounds were quantitatively analyzed at low concentrations (1-10 ng ml-1 with RSD 2%) to prevent micelle formation and to guarantee the method specificity. The limits of detection and quantification were 0.006 and 0.018 ng ml-1, and 1.0 and 3.84 ng ml-1 for DDAC and GEN, respectively. They both were studied from 46 samples collected from two school environments which were daily washed with the commercial chemicals. The results showed that concentrations of these biocide-type disinfectants were between 2.5-1029 ng ml-1. [ABSTRACT FROM AUTHOR]

Efficiently passivating germanium (Ge) surfaces is crucial to reduce the unwanted recombination current in high-performance devices. Chemical surface cleaning is critical to remove surface contaminants and Ge oxides, ensuring effective surface passivation after dielectric deposition. However, Ge oxides can rapidly regrow upon air exposure. To understand the surface evolution after wet cleaning, we present a comprehensive study comparing HF and HCl deoxidation steps on p-type Ge surfaces and monitor the surface as a function of air exposure time. Distinct oxide regrowth dynamics are observed: HF-treated samples exhibit swift regrowth of all Ge oxide states, whereas HCl-treated Ge surfaces exhibit a lower concentration of low degrees of oxidation and slower or no regrowth of high oxide states even after 110 min of air exposure. In addition, the presence of Ge–Cl bonds induces different oxidation dynamics compared to the Ge–OH bonds resulting from HF cleaning. This leads to varying surface electronic band structures, with HF-treated Ge exhibiting a strong positive band bending (+ 0.20 eV). Conversely, HCl-treated samples display a lower band curvature (+ 0.07 eV), mostly due to the presence of Ge–Cl bonds on the Ge surface. During air exposure, the increased GeO x coverage significantly reduces the band bending after HF, while a constant band bending is observed after HCl. Finally, these factors induce a reduction in the surface recombination velocity after wet etching. Combining both chemical and field-induced passivation, HF-treated Ge without rinsing exceeds 800 μ s. [ABSTRACT FROM AUTHOR]

Microelectromechanical systems (MEMS)-based filter with microchannels enables the removal of various microorganisms, including viruses and bacteria, from fluids. Membranes with porous channels can be used as filtration interfaces in MEMS hemofilters or mini-dialyzers. The main problems associated with the filtration process are optimization of membrane geometry and fouling. A nanoporous aluminum oxide membrane was fabricated using an optimized two-step anodization process. Computational strength modeling and analysis of the membrane with specified parameters were performed using the ANSYS structural module. A fuzzy simulation was performed for the numerical analysis of flux through the membrane. The membrane was then incorporated with the prototype for successive filtration. The fluid flux and permeation analysis of the filtration process have been studied. Scanning electron microscope (SEM) micrographs of membranes have been obtained before and after the filtration cycles. The SEM results indicate membrane fouling after multiple cycles, and thus the flux is affected. This type of fabricated membrane and setup are suitable for the separation and purification of various fluids. However, after several filtration cycles, the membrane was degraded. It requires a prolonged chemical cleaning. High-density water has been used for filtration purposes, so this MEMS-based filter can also be used as a mini-dialyzer and hemofilter in various applications for filtration. Such a demonstration also opens up a new strategy for maximizing filtration efficiency and reducing energy costs for the filtration process by using a layered membrane setup. [ABSTRACT FROM AUTHOR]

Objectives: The aim of the current study is to investigate the influence of mechanical stress as well as cleaning agents on the performance of various polyether ether ketone (PEEK) inserts for implant‐retained overdentures (IOD). Materials and Methods: Three different standard PEEK inserts were subjected to rapid artificial aging through storage in chemical denture cleaning agents (acetic acid, sodium hypochlorite, or sparkling denture cleaner) as well as demineralized water. The pre‐aged PEEK inserts were then placed in unilateral IOD and subjected to 200,000 chewing loads (5 kg ~ 50 N), with 5000 thermal cycles (5/55°C), and 1100 removal/insertion cycles (vertical movement 2 mm). Results: For all the PEEK inserts, the retention forces decreased significantly with an increasing number of mechanical load cycles and after exposure to all the cleaning agents. PEEK inserts aged by exposure to chemical cleaning agents showed a significantly higher decline in retention force than the inserts stored in water. Confocal laser scanning microscopy indicated that the decline in retention force might be caused by wear on the internal insert surface in contact with the patrix. Conclusions: Within the limitations of this study, it can be concluded that the application of chemical cleaning agents accelerates the decline in the retention forces of PEEK retentive inserts in IODs. [ABSTRACT FROM AUTHOR]

Membrane technology plays a critical role in solving worldwide water scarcity and security issues. However, membrane aging causes deterioration or complete failure of membrane performance. In this work, polyvinylidene fluoride (PVDF) membrane aging induced by ultraviolet (UV) and NaOCl were investigated and compared. The skin layer was completely destroyed in 2d by UV irradiation under a dry state, which further caused deformation in the sublayer and pore shrinkage. The water layer on the membrane surface protected the skin layer from damage by UV till 8d under the wet state. NaOCl had a moderate influence, the flux was firstly decreased as the hydrophobicity of the membrane increased, and then increased due to pore enlargement. Membrane aging also resulted in a lower virus rejection, which highlighted the biosafety concern in membrane-based wastewater treatment. Infrared and two-dimensional correlation spectroscopy confirmed that the hydrophilic additive was first oxidated in both processes. β-PVDF segment changed before α-PVDF under UV, during which the C C bond was formed by the dehydrofluorination reaction. But the α-PVDF segment was attacked firstly by NaOCl, the radical reaction occurred both at CH 2 -CF 2 and CH=CF segments. This work studied two aging patterns in the membrane lifecycle and demonstrated the aging mechanism, which shed light on membrane development and maintenance in the future. [Display omitted] [ABSTRACT FROM AUTHOR]

A granule-based simultaneous nitrification, anammox, and denitrification process in a membrane bioreactor (SNAD-MBR) was performed to investigate the influence of in-situ NaClO backwashing on biological performance and membrane fouling. First, the limit of the NaClO concentration for the SNAD granules was determined (20 mg/g·SS) in a short-term batch test. Then, three in-situ NaClO backwashing strategies (NaClO concentrations of 5-15 mg/g·SS with backwashing frequencies of 1/10-1/30 min) were implemented during long-term SNAD-MBR process. The results showed that the removal efficiencies of total nitrogen (TN) and chemical oxygen demand decreased from 92.69% and 94.19% to 81.82% and 85.39%, respectively, with an increase in the NaClO concentration in spite of a reduction in backwashing frequency. The deterioration of the biological performance could be explained by the inhibitory activities of the functional bacteria after long-term exposure to NaClO. Nevertheless, the stable contributions of autotrophic and heterotrophic processes to TN removal (Eanammox of 91.23%, Edenitrification of 8.77%) indicated a negligible impact of NaClO backwashing on the balance of the nitrogen removal pathways. Furthermore, membrane fouling was significantly suppressed when in-situ NaClO backwashing was performed with a relatively high frequency (1/1-10/20min) and a low concentration (5-10 mg/g·SS). However, a higher NaClO concentration (15 mg/g·SS) exacerbated membrane fouling, although the backwashing frequency was low. Meanwhile, the high fouling potential of the SNAD granules resulted from the high production of soluble microbial products (especially tryptophan protein-like substances) under NaClO stress. The possible underlying mechanism was the trade-off between the membrane scrubbing effect by NaClO and the variable physico-chemical properties of the SNAD granules. The optimal in-situ NaClO backwashing strategy that considered the process performance, membrane fouling, and permeate production was a NaClO concentration of 15 mg/g·SS and a backwashing frequency of 1/20 min. The results provide guidance for in-situ NaClO backwashing of the SNAD-MBR process. [ABSTRACT FROM AUTHOR]

Reverse osmosis (RO) membranes are widely used in seawater and brackish water desalination. Although RO membranes achieve high salt removal > 99%, their application is hindered by fouling, thus causing reduction in permeate flux, salt rejection and degradation of the membrane leading to shorter membrane lifespan. This study reviewed fouling of RO membrane during desalination processes. Also, nanofiltration (NF) membrane are briefly discussed due to their remarkable salt rejection efficiency for water softening. Various types of fouling, mechanisms and governing parameters are discussed in detail. The implications of fouling on membrane physicochemical properties and filtration performance are reviewed. Fouling mitigation strategies are presented, predominantly focusing on currently adopted methods. New fouling mitigation strategies are presented together with their challenges and feasibility assessment for adoption at pilot scale. Finally, recommendations are made on possible pretreatment approaches with the potential fouling reduction in seawater desalination. • Fouling alters membrane physico-chemical properties leading to poor performance. • The operation cost of NF and RO increases upon membrane fouling. • Chemical cleaning degrades polymeric membranes and reduces their lifespan. • New environmentally friendly fouling control methods have potential for the future. • Membrane surface modification improves antifouling properties. [ABSTRACT FROM AUTHOR]

Facilities in power plants and thermal power plants must operate at high efficiency. Their efficiency largely depends on the quality of water as a cooling medium. Water is the most commonly used cooling medium in processes because it is generally available and has a large thermal capacity. The use of water results in a variety of consequences. The different compositions of water can cause scale deposits and contribute to the corrosion of system components. The exacerbation of the problem depends on the composition of the water and the operating conditions of the system. The lack of a low-cost and quick way to remove accumulated deposits that is also safe due to the chemicals used means that cleaning the system of deposits is not widely undertaken, especially in cases of small thermal power plants. Therefore, chemical cleaning is an extremely important part of plant operation. Due to the often-individual characteristics of each installation and the different sources of water as a refrigerant, it is important to know the different methods of descaling an installation. This article provides an overview of methods for descaling installations. Each of them has its own specific properties, allowing an individual approach to boiler scale removal. [ABSTRACT FROM AUTHOR]

In this work, novel sandwich-type asymmetric ceramic microfiltration membranes with a sea urchin-like mullite whisker skeleton were prepared one step. Their structural properties and oil-water separation performance were investigated. The results show that after sintering at 1400 °C, the prepared membrane possesses good hydrophilic, underwater oleophobic, and anti-fouling properties. During the continuous separation of a 300 mg/L oil-in-water emulsion, a maximum stable flux of 267 L·m−2·h−1 was achieved without membrane cleaning. After chemical cleaning and simple physical cleaning, the membranes recovered to a steady flux of 397 L·m−2·h−1 and 305 L·m−2·h−1, respectively, and maintained a 95% oil rejection. The good underwater oleophobicity and selective permeability brought about by the flat-lying whiskers on the top surface, coupled with the efficient water channels between the sea urchin-like structures inside the membrane, are considered to be the main reasons for its improved separation characteristics over conventional low-cost ceramic membranes. [ABSTRACT FROM AUTHOR]

The ever-increasing demand for producing drinking water from seawater triggered the development of competitive and advanced pretreatment for seawater reverse osmosis desalination plants. Ultrafiltration as a pretreatment has been optimized to compact design utilizing multi-capillary polyethersulfone (PES) membrane, whereas the DuPont™ Multibore™ membrane with seven capillaries has been employed in numerous large-scale applications with proven durability. The next generation of PES membranes has now been developed: a multi-bore PES membrane with 19 capillaries and an inner diameter of 0.7 mm, called DuPont™ Multibore™ PRO, within the recently launched DuPont™ IntegraTEC™ ultrafiltration portfolio. This new membrane geometry enables more membrane surface area per module, decreasing the number of required modules, hence decreasing the overall physical footprint for membrane modules by up to 17%. As a result, less material usage per m2 membrane surface area is needed to have a positive sustainability impact on module production, transportation, as well as end-of-life handling, leading to a significant overall reduction of the CO2 footprint. This study presents the results of the DuPont™ Multibore™ PRO being operated in a surface water and a seawater application. The surface water site is at a river in Germany. The seawater site is located at the Gulf in Qatar. This paper presents results of evaluation tests performed at these two locations with a multi-capillary ultrafiltration membrane. All results show comparable performance in terms of reversible fouling, chemical cleaning pattern, recovery, filtration flux and overall stable operation. At the surface water site, coagulant employed in the same concentration for the DuPont™ Multibore™ with 7 capillaries as for the DuPont™ Multibore™ PRO. Here, the feed water quality fluctuations in terms of turbidity are significantly higher compared to the seawater sites reflecting more stressful operating conditions. Additionally, the organic background level is higher with 5-8 mg/L dissolved oxygen carbon at the river water site. Polyaluminium chloride-based coagulation captures organic components which are then retained by the membranes. Due to the very unfavorable interactions with PES membrane surfaces, the fouling layer of coagulant is completely reversible during backwashes. [ABSTRACT FROM AUTHOR]

Objectives: The aim of the present study was to evaluate the cleaning efficacy of two mechanical and two chemical protocols in the decontamination of implant surfaces. Methods: In total, 123 commercially available implants were mounted in plastic models mimicking peri‐implant circumferential intra‐bony defects. A multispecies biofilm was grown on implant surfaces. Mechanical (air‐polishing (AP), rotating titanium brush (TiB)) and chemical decontamination (alkaline electrolyzed water, N‐acetyl‐L‐cysteine) protocols were used. Cleaning efficacy in terms of residual biofilm area, chemical surface properties, and bacterial counts were analyzed by scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, and quantitative polymerase chain reaction. Results: Surface decontamination protocols including use of an AP device or a rotating TiB were superior in terms of biofilm removal and in reducing atomic% of Carbon on implant surfaces when compared to methods restricted to wiping with gauze. The use of chemical agents as adjuncts to the mechanical cleaning protocols provided no relevant overall benefit over saline. No treatment modality, however, resulted in complete biofilm removal. Conclusion: Air‐polishing and rotating TiB were more effective implant surface decontamination protocols than wiping with gauzes. Use of chemical agents did not improve cleaning efficacy. [ABSTRACT FROM AUTHOR]

Membrane separation has been widely utilized to eliminate pollutants from wastewater. Among them, a polyacrylonitrile (PAN) ultrafiltration (UF) membrane has presented outstanding stability, and distinguished chemical and thermal properties. However, UF membranes inevitably incur fouling issues during their operation procedure caused by contaminant adhesion on the membrane surface, which would restrict the operational efficiency and increase the maintenance cost. The conventional physical and chemical cleaning is not an effective technique to reduce the fouling due to the additional chemical addition and inevitable structure damage. Recently, UF membranes combined with photocatalytic materials are suggested to be a useful approach to conquer the membrane fouling issues. Herein, TiO2 nanoparticles were utilized to blend with a PAN casting solution for fabricating a composite UF membrane via a phase inversion method. With a certain TiO2 addition, the obtained membranes presented an enhancement of hydrophilicity, which could promote the water permeability and antifouling performance. The optimized M3 membrane prepared with 15.0 wt% PAN and 0.6 wt% TiO2 exhibited an excellent water permeability up to 207.0 L m−2 h−1 bar−1 with an outstanding 99.0% BSA rejection and superior antifouling property. In addition, the photocatalytic TiO2 nanoparticles endowed the M3 membrane with a remarkable self-cleaning ability under the UV irradiation. This facile construction method offered new insight to enhance the UF membrane separation performance with an enhanced antifouling ability. [ABSTRACT FROM AUTHOR]

This paper describes the results of a multi-technological analytical protocol performed on the painted surface of an Egyptian wooden coffin and documents the conservation processes of a wooden coffin covered with a black resin layer and coloured materials in Dahshur Archaeological Area dating back to the late period. It uses visual observation, optical microscopy (OM), technical imaging, 2D and 3D programmes, and a scan made using an electron microscope coupled with an Energy Dispersive X-ray (SEM-EDX), X-ray diffraction (XRD). Wood identification was also carried out. The results showed the use of yellow ochre for the yellow painted layer; the ground layer was calcium carbonate with gypsum, and the fabric layer was linen. The conservation processes of the wooden coffin included mechanical and chemical cleaning; reassembling the separated wooden parts, ground layer, and black resin layers; filling the edge of the ground layer; and consolidating the wood, black resin, and painted layer. The conservation processes included mechanical cleaning using soft brushes, chemical cleaning using xylene and distilled water for the black resin layer and ethyl alcohol and distilled water for the painted layer, stabilisation of the separated ground layer using Paraloid B72, filling the cracks of the ground layers using glass microballoons with Paraloid B72, and consolidating the painted layer with nano-silica with Klucel G (hydroxypropyl cellulose) (0.5% concentration). [ABSTRACT FROM AUTHOR]

Dry buffer layer deposition techniques for chalcopyrite (CIGSSe)-based thin-film solar cells lack the surface-cleaning characteristics of the commonly used CdS or Zn(O,S) wet-chemical bath deposition. A UV-induced ozone and/or a low-energy Ar+-ion treatment could provide dry CIGSSe surface cleaning steps. To study the impact of these treatments, the chemical surface structure of a CIGSSe absorber is investigated. For this purpose, a set of surface-sensitive spectroscopic methods, i.e., laboratory-based x-ray photoelectron spectroscopy and x-ray-excited Auger electron spectroscopy, is combined with synchrotron-based soft x-ray emission spectroscopy. After treatment times as short as 15 s, the UV-induced ozone treatment decreases the amount of carbon adsorbates at the CIGSSe surface significantly, while the oxygen content increases. This is accompanied by the oxidation of all absorber surface elements, i.e., indium, selenium, sulfur, and copper. Short (60 s) low-energy Ar+-ion treatments, in contrast, primarily remove oxygen from the surface. Longer treatment times also lead to a removal of carbon, while extremely long treatment times can also lead to additional (likely metallic) Cu phases at the absorber surface as well. [ABSTRACT FROM AUTHOR]

The growing freshwater scarcity has caused increased use of membrane desalination of seawater as a relatively sustainable technology that promises to provide long-term solution for the increasingly water-stressed world. However, the currently used membranes for desalination on an industrial scale are inevitably prone to fouling that results in decreased flux and necessity for periodic chemical cleaning, and incur unacceptably high energy cost while also leaving an environmental footprint with unforeseeable long-term consequences. This extant problem requires an immediate shift to smart separation approaches with self-cleaning capability for enhanced efficiency and prolonged operational lifetime. Here, we describe a conceptually innovative approach to the design of smart membranes where a dynamic functionality is added to the surface layer of otherwise static membranes by incorporating stimuli-responsive organic crystals. We demonstrate a gating effect in the resulting smart dynamic membranes, whereby mechanical instability caused by rapid mechanical response of the crystals to heating slightly above room temperature activates the membrane and effectively removes the foulants, thereby increasing the mass transfer and extending its operational lifetime. The approach proposed here sets a platform for the development of a variety of energy-efficient hybrid membranes for water desalination and other separation processes that are devoid of fouling issues and circumvents the necessity of chemical cleaning operations. The performance of membrane desalination of seawater is hampered by fouling. Here the authors develop smart gating hybrid membranes by surface coating with polymer-embedded thermosalient crystals. These membranes enhance pure water flux by over 40% in saltwater desalination by osmotic distillation. [ABSTRACT FROM AUTHOR]

Membrane distillation (MD) is an emerging process with a proven ability to recover freshwater from streams with a wide range of salinities. However, MD is susceptible to biofouling. This study explores the efficiency of different cleaning strategies in biofilm removal during seawater MD. Hydraulic cleaning and chemical cleanings with 0.3%w w−1 ethylenediaminetetraacetic acid (EDTA), 0.3%w w−1 NaOCl, and 3%w w−1 citric acid were tested. The results showed that permeate flux recovery increased in the order of hydraulic cleaning <3%w w−1 citric acid <0.3%w w−1 NaOCl ≈0.3%w w−1 EDTA. Membrane cleanings substantially reduced the thickness of the residual biofilm layer and decreased its bacterial concentration and resistance to vapor pressure. The post-cleaning permeate conductivities were low suggesting that employed cleaning protocols did not cause pore wetting of hydrophobic polytetrafluoroethylene microporous (0.22 μm) membrane, and membrane rejection properties remained stable. [ABSTRACT FROM AUTHOR]

From the perspective of resource recovery, this paper summarized the physical and chemical method ( evaporation method, the remove method, adsorption, membrane separation, magnesium ammonium phosphate precipitation) and recycling organic waste anaerobic biological method and other methods in the fermented liquid ammonia nitrogen form and its mechanism, analyses the anaerobic fermentation liquor pH, temperature, gas liquid ratio and suspended solids and organic matter, high concentration of ammonia nitrogen on the effects of the ammonia nitrogen recycling in view of the existing in the running cost is high, the adsorption capacity is small, membrane fouling and concentration ability is limited and difficult problems such as separation, puts forward the delve into a stable and efficient, low cost, convenient operation, nitrogen recovery technology and combination of the process and optimize the process conditions of research direction, in order to organic waste anaerobic fermentation contained ammonia nitrogen utilization to provide the reference. [ABSTRACT FROM AUTHOR]

Foulants build-up on the membrane surface followed by polarization is considered to be one of the most critical issues that have limited the application of membranes in different industries because they reduce the permeate flux, increase the required feed pressure, reduce the time intervals between chemical cleanings, and finally, shorten the lifetime of the membranes. Several strategies have been proposed to reduce and control the membrane polarization and fouling mitigation for increasing the permeate flux. The strategies include inserting different spacers and turbulence promoters, pulsation of feed, back-pulsation of permeate, the introduction of air bubbles, patterning of the membrane surface, etc. Among these methods, surface patterning of membranes (MSPs) has been one of the most promising ways to reduce and control polarization at the membrane surface for mitigation of fouling which has recently received much attention. In this regard, in this paper, the state-of-the-art surface patterned membranes for the treatment of different feeds are reviewed. Also, various methods for fabrication and construction of the surface patterned polymeric membranes and the enhancements induced by the surface patterns on the membrane processes' performance are discussed in detail. Finally, the future perspective of this technology is forecast. [Display omitted] • Different techniques for fabrication of surface patterned membranes are reviewed. • The mechanisms and strategies of membrane surface patterning are reviewed. • Performance of the surface patterned membranes in different applications are reviewed. • CFD opportunity for designing the surface patterned membranes is expressed. [ABSTRACT FROM AUTHOR]