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In this study, nickel ferrite (NiFe 2 O 4 ) nanoparticles were synthesized using the Pechini sol-gel method and modified with sodium docusate surfactant. The modified nanoparticles showed an enhanced adsorption capacity of 384.62 mg/g for crystal violet dye, compared to 237.53 mg/g for unmodified NiFe 2 O 4 . Characterization was performed using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), and scanning electron microscopy (SEM) techniques. The adsorption process was spontaneous, exothermic, and followed the Langmuir isotherm and pseudo-second-order kinetic model. Optimal conditions for maximum dye removal were achieved at pH 10, 50 min, and 298 K. Additionally, the synthesized adsorbents demonstrated excellent regeneration and reusability over five adsorption-desorption cycles with minimal efficiency loss., Competing Interests: Declarations Consent for publication Not applicable. Competing interests The authors declare no competing interests. Consent to participate Not applicable. Ethics approval Not applicable., (© 2024. The Author(s).)

A nanocomposite of tannic acid and cellulose nanowhiskers (CNW)-reinforced polysulfone (PSF) was used to develop a metallochromic nanofibrous membrane sensor for iron(III) in aqueous media. Tannic acid was used as an active detecting probe, whereas the CNW@PSF composite was employed as a hosting material. Cellulose nanowhiskers (7-12 nm) were obtained from microcrystalline cellulose (MCC). According to the coloration parameters, a bathochromic shift from colorless (415 nm) to purple (561 nm) occurs when ferric cations bind to the phenolic hydroxyls of the tannic acid probe. The concentration of ferric was found to be directly correlated to the extent of the color change, demonstrating a detection limit of 0.1-250 ppm. This could be attributed to the creation of a coordinative complex between ferric ions and phenolic tannic acid. The generated nanofibers were inspected by energy-dispersive X-ray (EDX) and scanning electron microscopy (SEM). The electrospun nanofibrous membrane showed an average diameter between 75 and 150 nm. The tannic acid-containing nanofibers are remarkably reusable and simple. The tannic acid-encapsulated polysulfone nanofibrous membrane was used to detect various metal ions, demonstrating a high selectivity for Fe 3+ . The ideal pH range for the identification of Fe 3+ was determined to be in the range of 4.25-6.75., Competing Interests: Declaration of competing interest The authors declare that they have no competing interests., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Photochromic inks have shown disadvantages, such as poor durability and high cost. Self-healable hydrogels have shown photostability and durability. Herein, a viologen-based covalent polymer was printed onto a paper surface toward the development of a multi-stimuli responsive chromogenic sheet with thermochromic, photochromic, and vapochromic properties. Viologen polymer was created by polymerizing a dialdehyde-based viologen with a hydroxyl-bearing dihydrazide in an acidic aqueous medium. The viologen polymer was well immobilized as a colorimetric agent into a polyvinyl alcohol (PVA)/tricarboxy cellulose (TCC)-based self-healable hydrogel. The viologen/hydrogel nanocomposite films were applied onto a paper surface. The coloration measurements showed that when exposed to ultraviolet light, the orange layer printed on the paper surface switched to green. The photochromic film was used to develop anti-counterfeiting prints using the organic hydrogel composed of a PVA/TCC composite and a viologen polymer. Reversible photochromism with strong photostability was observed when the printed papers were exposed to UV irradiation. A detection limit was monitored in the range of 0.5-300 ppm for NH 3(aq) . The exposure to heat (70 °C) was found to reversibly initiate a colorimetric change.

Smart colorimetric packaging has been an important method to protect human health from external hazardous agents. However, the currently available colorimetric detectors use synthetic dye probes, which are costly, toxic, difficult to prepare, and non-biodegradable. Herein, an environmentally friendly cellulose nanocrystal (CNC)-supported polyvinyl alcohol (PVA) nanofibrous membrane was developed for the colorimetric monitoring of food spoilage. Anthocyanidin (ACY) is a naturally occurring spectroscopic probe that was isolated from pomegranate ( Punica granatum L.). By encapsulating the anthocyanin probe in electrospun polyvinyl alcohol fibers in the presence of a mordant (M), M/ACY nanoparticles were generated. After exposure to rotten shrimp, an investigation on the colorimetric changes from purple to green for the smart nanofibrous fabric was conducted using the coloration parameters and absorbance spectra. In response to increasing the length of exposure to rotten shrimp, the absorption spectra of the anthocyanin-encapsulated nanofibrous membrane showed a wavelength blueshift from 580 nm to 412 nm. CNC displayed a diameter of 12-17 nm. The nanoparticle diameter of M/ACY was monitored in the range of 8-13 nm, and the nanofiber diameter was shown in the range of 70-135 nm. Slight changes in comfort properties were monitored after encapsulating M/ACY in the nanofibrous fabric.

The colorless and odorless nerve agents can cause paralysis and even death. The development of novel composite-based microporous strips has allowed for the rapid and visual detection of diisopropyl phosphorofluoridate (DIPF) nerve agent mimics. The active methyl-containing tricyanofuran and 4-aminobenzotrifluoride diazonium salt were azo-coupled in a straightforward manner to produce a new benzotrifluoride (BFT)-comprising tricyanofuran (TCF) hydrazone colorimetric probe. The molecular structure of the benzotrifluoride-bearing hydrazone (BFTH) was explored by different spectroscopic techniques. Microfibrillated cellulose (MFC) was produced using a green process from sugarcane bagasse, an agriculture waste that is notorious for being a solid pollution. Consequently, discovering a straightforward procedure to convert bagasse into valuable materials has been of utmost importance. MFC displayed diameters of 0.25-2 μm, whereas the sensory films exhibited pore diameters of 0.5-2.25 μm. Various quantities of the BFTH chromophore were used to create benzotrifluoride-bearing hydrazone/microfibrillated cellulose/carboxymethyl cellulose (BFTH/MFC@CMC) composites. The absorbance band of the hydrazone-immobilized composite increased from 435 nm to 580 nm as the content of DIPF was raised. When exposed to DIPF, the dipstick color shifted from orange to pink, according to the CIE Lab measurements. The sensor strip showed a detection limit to DIPF between 5 and 200 ppm., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Smart packaging materials have been used to protect human health from environmental hazards by sending real-time colorimetric signals for changes in the food packaging environment. However, the colorimetric material sensors use synthetic sensor dyes, which are toxic, expensive, non-biodegradable, and difficult to prepare. Herein, a simple strategy is presented for the development of an environmentally-friendly halochromic wood able to change color upon exposure to spoilage of food. A combination of anthocyanin (Ac)/aluminum (Al) mordant (Ac/Al) nanoparticles and cellulose nanowhiskers (CNW)-reinforced polyvinyl alcohol (PVA) was infiltrated into a delignified wood to produce a translucent wood with halochromic properties. CNW were employed as reinforcement agent to improve the mechanical performance of PVA. Additionally, CNW function as a dispersing agent to prevent agglomeration of Ac/Al nanoparticles. The diameters of CNW are in the range of 12-19 nm, whereas Ac/Al particles showed diameters of 9-22 nm. The smart wood changed color from purplish to colorless when exposed to food spoilage. A hypsochromic change from 539 nm to 370 nm was shown by the anthocyanin receptor when the spoilage level of food increased. This could be attributed to the pH-driven molecular switching of anthocyanin, leading to charge delocalization., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Smart polymer glue with photoluminescence and water-repellent properties was developed. The luminescent adhesive continues emitting light for up to 120 min after turning the excitation source off. Nanoparticles of lanthanide strontium aluminum oxide (LSAO) (8-13 nm) were consistently immobilized into carboxymethyl cellulose-reinforced gum Arabic (CMC/GA) adhesive. Using various concentrations of LSAO, the generated adhesives showed emission intensity at 519 nm and an excitation band at 365 nm. Depending on LSAO content, both of afterglow and fluorescence emission were monitored. Photochromism was detected as the transparent adhesive film changes color to green under ultraviolet irradiation. A greenish-yellow lightening in a darkened place was also observed. The nanocomposite resistance to scratches and hydrophobicity were found to enhance as the LSAO content was increased in the carboxymethyl cellulose-reinforced gum Arabic matrix. The LSAO@CMC/GA nanocomposite showed high durability and photostability. The present strategy proved the viability of a potential mass production toward photoluminescent adhesives for various smart applications, such as smart packaging, anti-counterfeiting printing, smart windows, and safety signs., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Smart photochromic and fluorescent textile refers to garments that alter their colorimetric properties in response to external light stimulus. Cotton fibers have been reported as a main resource for many textile and non-textile industries, such as automobiles, medical devices, and furniture applications. Cotton is a natural fiber that is distinguished with breathability, softness, cheapness, and highly absorbent. However, there have been growing demands to find other resources for cotton textiles at high quality and low cost for various applications, such as sensor for harmful ultraviolet radiation. Herein, we present a novel method toward luminescent and photochromic nonwoven textiles from recycled cotton waste. Using the screen-printing technology, a cotton fabric that is both photochromic and fluorescent was developed using aqueous inorganic phosphor nanoparticles (10-18 nm)-containing printing paste. Both CIE Lab color coordinates and photoluminescence spectra showed that the transparent film printed on the nonwoven fabric develops a reversible green emission (519 nm) under ultraviolet light (365 nm), even at low pigment concentration (2%) in the printing paste. Colorfastness of printed fabrics showed high durability and photostability., (© 2024 John Wiley & Sons Ltd.)

Photochromic wood materials are very important and appealing for smart windows. Herein, we describe the development of transparent photochromic wood that can change its color under ultraviolet and visible lights. Photoluminescent transparent wood was prepared by delignification of wood followed by infiltration with a combination of gum Arabic/chitosan/acrylic acid (ACA), lanthanide-activated aluminum strontium oxide (LASO) as a photoluminescent, and Genipin as a cross-linking agent. The produced mixture was then infused into the lignin-modified wood substrate. In order to develop a luminescent colorless wood, the LASO phosphor must be well-distributed in the ACA solution without aggregation. According to the colorimetric parameters and photoluminescence spectra, this optically active wooden window switched color from transparent in daylight to green when UV-irradiated. Transmission electron microscopy (TEM) was employed to examine the morphological features of phosphor nanoparticles. The morphological features of the developed smart wooden window were investigated by scanning electron microscopy (SEM), X-ray fluorescent spectroscopy (XRF), and energy-dispersive X-ray analyzer (EDX). The mechanical performance was explored by investigating both hardness and resistance to scratches. The luminescent woods displayed an emission band at 518 nm when excited at 365 nm. The superhydrophobic performance and ultraviolet shielding of woods were improved upon increasing the phosphor content., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Multifunctional transparent woods have recently attracted a great interest as efficient products for many applications, such as smart window and smart packaging. Herein, a transparent wood with several desirable properties, including flame-retardant activity, ultraviolet shielding, superhydrophobicity, good roughness, durability and photostability was developed. The current photoluminescent wood showed a remarkable capacity to keep releasing light in the dark for extended durations. Multifunctional transparent wood was prepared by infiltrating a delignified wooden bulk with a combination of polyvinyl alcohol (PVA), ammonium polyphosphate (APP), cellulose nanocrystals, and rare-earth strontium aluminate nanoparticles (RSAN). Cellulose nanocrystals were prepared from microcrystalline cellulose, and used as reinforcement nanofiller to enhance the mechanical strength of the polyvinyl alcohol matrix and a dispersant agent to avoid agglomeration of RSAN. RSAN displayed diameters of 8-16 nm, while cellulose nanocrystals displayed lengths of 75-150 nm and diameters of 5-10 nm. According to photoluminescence spectra and the colorimetric space coordinates reported by the CIE Lab parameters, the transparent wood changed color to bright green when exposed to UV irradiation. For the produced phosphorescent wood surfaces, an absorption band was detected at 365 nm to generate an emission band at 519 nm., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The colorless ammonia gas has been a significant intermediate in the industrial sector. However, prolonged exposure to ammonia causes harmful effects to organs or even death. Herein, an environmentally friendly solid-state ammonia sensor was developed utilizing colorimetric polycaprolactone-co-polylactic acid nanofibrous membrane. Pomegranate (Punica granatum L.) peel contains anthocyanin (ACN) as a naturally occurring spectroscopic probe. A mordant (potassium aluminum sulfate) is used to immobilize the anthocyanin direct dyestuff inside nanofibers, generating mordant/anthocyanin (M/ACN) coordinated complex nanoparticles. When exposed to ammonia, the color change of anthocyanin-encapsulated polycaprolactone-co-polylactic acid nanofibrous membrane from purple to transparent was examined by absorbance spectra and CIE Lab color parameters. With a quick colorimetric shift, the polycaprolactone-co-polylactic acid fabric exhibits a detection limit of 5-150 mg/L. The absorbance spectra showed a hypsochromic shift when exposed to ammonia, displaying an absorption shift from 559 nm to 391 nm with an isosbestic point of 448 nm. Scanning electron microscopy (SEM) images revealed that the polycaprolactone-co-polylactic acid nanofibers had a diameter of 75-125 nm, whereas transmission electron microscopy (TEM) images revealed that M/ACN nanoparticles exhibited diameters of 10-20 nm., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

An inorganic/organic nanocomposite was used to develop an afterglow and color-tunable smart window. A combination of polylactic acid (PLA) plastic waste as an environmentally-friendly hosting agent, and lanthanide-activated strontium aluminum oxide nanoparticles (SAON) encapsulated with silica nanoparticles (SAON@Silica) as a photoluminescent efficient agent resulted in a smart organic/inorganic nanocomposite. In order to prepare SAON-encapsulated silica nanoparticles (SAON@Silica), the SAON nanoparticles were coated with silica using the heterogeneous precipitation method. By using transmission electron microscopy (TEM), SAON showed a diameter range of 5-12 nm, while the SAON@Silica nanoparticles showed a diameter range of 50-100 nm. In order to ensure the development of a colorless plastic film, a homogeneous dispersion of the phosphorescent Phosphor@Silica nanoparticles throughout the plastic bulk was confirmed. CIE Lab coordinates and luminescence spectra were used to study the color shift characteristics. Under visible light conditions, the plastic films were transparent. The photoluminescent films emitted green light at 525 nm when excited at 375 nm. The hydrophobicity and ultraviolet protection were enhanced without altering the fundamental physico-mechanical performance of the plastic sheet. The current color-tunable plastic can be used in many potential applications, such as warning signs, anti-counterfeiting barcodes, smart windows, and protective apparel., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

This study investigated the electrochemical behavior of NiCu, NiCu/GO, and NiCu/rGO nanocomposites designed by combining a modified Hummers' method and hydrothermal technique. The prepared nanocomposites are tested as electrocatalysts in direct alcohol oxidation fuel cells (DAFCs) to identify the role of GO and rGO as catalyst supports for the enhancement of the NiCu composite performance. The production of the NiCu/GO and NiCu/rGO composites was demonstrated by FTIR spectroscopy, EDX, and SEM analyses. In DAFCs experiments, NiCu/rGO has better catalytic activity than pure NiCu and NiCu/GO composites, whereas the use of rGO and GO as supports enhances the performance of NiCu by 468.2% and 377.7% in methanol and 255.6% and 105.9% in ethanol, respectively. The higher performance was caused by the increased density of active dots and the combined electronic effects in the designed catalysts. The stabilities of the catalysts and charge carriers' dynamics are studied using chronoamperometry and electrochemical impedance spectroscopy., Competing Interests: The authors declare no conflict of interest., (This journal is © The Royal Society of Chemistry.)

Gas sensing is of significant importance in a wide range of disciplines, including industrial safety and environmental monitoring. In this work, a low-cost SILAR (Successive Ionic Layer Adsorption and Reaction) technique was employed to fabricate pure CuO, Zn-doped CuO, and Na-doped CuO nanotextured films to efficiently detect CO 2 gas. The structures, morphologies, chemical composition, and optical properties of all films are characterized using different tools. All films exhibit a crystalline monoclinic phase (tenorite) structure. The average crystallite size of pure CuO was 83.5 nm, whereas the values for CuO/Zn and CuO/Na were 73.15 nm and 63.08 nm, respectively. Subsequently, the gas-sensing capabilities of these films were evaluated for the detection of CO 2 in terms of sensor response, selectivity, recovery time, response time, and limits of detection and quantification. The CuO/Na film offered the most pronounced sensitivity towards CO 2 gas, as evidenced by a sensor response of 12.8% at room temperature and a low limit of detection (LoD) of 2.36 SCCM. The response of this sensor increased to 64.5% as the operating temperature increased to 150 °C. This study thus revealed a brand-new CuO/Na nanostructured film as a highly effective and economically viable sensor for the detection of CO 2 .

Water treatment is regarded as one of the essential elements of sustainability. To lower the cost of treatment, the wastewater volume is reduced via the osmotic process. Here, mixed-matrix woven forward osmosis (MMWFO) PES membranes modified by a TiO 2 /Na 2 Ti 3 O 7 (TNT) nanocomposite were fabricated for treating water from different sources. Various techniques were used to characterize the TNT nanocomposite. The crystal structure of TNT is a mix of monoclinic Na 2 Ti 3 O 7 and anorthic TiO 2 with a preferred orientation of (2-11). The SEM image shows that the surface morphology of the TNT nanocomposite is a forked nano-fur with varying sizes regularly distributed throughout the sample. The impact of TNT wt.% on membrane surface morphologies, functional groups, hydrophilicity, and performance was investigated. Additionally, using distilled water (DW) as the feed solution (FS), the effects of various NaCl concentrations, draw solutions, and membrane orientations on the performance of the mixed-matrix membranes were tested. Different water samples obtained from various sources were treated as the FS using the optimized PES/TNT (0.01 wt.%) MMWFO membrane. Using textile effluent as the FS, the impact of various NaCl DS concentrations on the permeated water volume was investigated. The results show that the MMWFO membrane generated with the TNT nanocomposite at a 0.01 wt.% ratio performed better in FO mode. After 30 min of use with 1 M NaCl and various sources of water as the FS, the optimized MMWFO membrane provided a steady water flow and exhibited antifouling behavior. DW performed better than other water types whenever it was used owing to its greater flow (136 LMH) and volume reduction (52%). Tap water (TW), textile industrial wastewater (TIWW), gray water (GW), and municipal wastewater (MW) showed volume reductions of 41%, 34%, 33%, and 31.9%, respectively. Additionally, when utilizing NaCl as the DS and TIWW as the FS, 1 M NaCl resulted in more permeated water than 0.25 M and 0.5 M, yet a higher volume reduction of 41% was obtained.

We introduced, for the first time, a membrane composed of nanostructured self-polyether sulphone (PES) filled with graphene oxide (GO) applied to photoelectrochemical (PEC) water splitting. This membrane was fabricated through the phase inversion method. A variety of characteristics analysis of GO and its composite with PES including FTIR, XRD, SEM, and optical properties was studied. Its morphology was completely modified from macro voids for bare PES into uniform layers with a random distribution of GO structure which facilitated the movement of electrons between these layers for hydrogen production. The composite membrane photocathode brought a distinct photocurrent generation (5.7 mA/cm 2 at 1.6 V vs. RHE). The optimized GO ratio in the membrane was investigated to be PG2 (0.008 wt.% GO). The conversion efficiencies of PEC were assessed for this membrane. Its incident photon-to-current efficiency (IPCE) was calculated to be 14.4% at λ = 390 nm beside the applied bias photon-to-current conversion efficiency (ABPE) that was estimated to be 7.1% at -0.4 V vs. RHE. The stability of the PG2 membrane after six cycles was attributed to high thermal and mechanical stability and excellent ionic conductivity. The number of hydrogen moles was calculated quantitively to be 0.7 mmol h -1 cm -2 . Finally, we designed an effective cost membrane with high performance for hydrogen generation.

A systematic study integrating laboratory, analytical, and case study field trial was conducted to figure out the effective adsorbent that could be used for the removal of Congo red (CR) dye from industrial wastewater effluent. The ability of the zeolite (Z) to adsorb CR dye from aqueous solutions was evaluated after it was modified by the Cystoseira compressa algae (CC) (Egyptian marine algae). Zeolite, CC algae were combined together in order to form the new composite zeolite/algae composite (ZCC) using wet impregnation technique and then characterized by the aid of different techniques. A noticeable enhancement in the adsorption capacity of newly synthesized ZCC was observed if compared to Z and CC, particularly at low CR concentrations. The batch style experiment was selected to figure out the impact of various experimental conditions on the adsorption behavior of different adsorbents. Moreover, isotherms and kinetics were estimated. According to the experimental results, the newly synthesized ZCC composite might be applied optimistically as an adsorbent for eliminating anionic dye molecules from industrial wastewater at low dye concentration. The dye adsorption on Z and ZCC followed the Langmuir isotherm, while that of CC followed the Freundlich isotherm. The dye adsorption kinetics on ZCC, CC, and Z were agreed with Elovich, intra-particle, and pseudo-second-order kinetic models, correspondingly. Adsorption mechanisms were also assessed using Weber's intraparticle diffusion model. Finally, field tests showed that the newly synthesized sorbent has a 98.5% efficient in eliminating dyes from industrial wastewater, authorizing the foundation for a recent eco-friendly adsorbent that facilitate industrial wastewater reuse., (© 2023. The Author(s).)

CoO/Co 3 O 4 nanoparticles (CoO/Co 3 O 4 NPs) were synthesized with egg white. The effectiveness of CoO/Co 3 O 4 NPs to inhibit the corrosion of carbon steel has verified in acidic medium (1 M HCl). It has been found that Langmuir adsorption isotherm is the dominant adsorption process of CoO/Co 3 O 4 NPs on the surface of low-carbon steel. The thermodynamic parameters also demonstrated that the adsorption process of CoO/Co 3 O 4 NPs was a physicochemical, spontaneous, and exothermic process. The electrochemical impedance spectroscopy technique and potentiodynamic polarization were applied. The results obtained in this study showed that CoO/Co 3 O 4 NPs acted as a mixed inhibitor for the anodic reaction and the cathodic reaction, and the efficiency to inhibit the corrosion was 93% at 80 ppm of the inhibitor. The results of scanning electron microscopy (SEM) technique, energy-dispersive X-ray spectroscopy (EDS), and X-ray electron spectroscopy (XPS) confirmed the effectiveness that was obtained using the inhibitor to protect the surface of low carbon steel. Thus, low-carbon steel can be protected against corrosion in acidic medium using CoO/Co 3 O 4 NPs as inhibitors.

It is generally believed that the most challenging impediment for the utilization of cellulose acetate (CA) in the medical field is its hydrophobicity and disability to poison the harmful microbes. Therefore, in this contribution, we aimed to prepare an environmentally scaffold-based CA loaded with copper nanoparticles (CuONPs), which are expected to not only improve the hydrophilicity of the prepared nanofibers, but also have an effective ability to kill such harmful and infectious microbes that are abundant in wounds. The obtained results attested that the generated nanofibers became thicker with increasing the content of CuONPs in CA nanofibers. The roughness average increased from 143.2 to 157.1 nm, whereas the maximum height of the roughness (R t ) increased from 400.8 to 479.9 nm as going from the lowest to the highest content of CuONPs. Additionally, the contact angle of the prepared nanofibers decreased from 105.3° (CA alone) to 85.4° for CuONPs@CA. Significantly, biological studies revealed that cell viability and anti-bacterial potency were improved upon incorporating CuONPs into CA solution. Correspondingly, their inhibition zones reached 18 ± 3 mm, and 16 ± 2 mm for nanofibrous scaffolds having 12.0CuO@CA, besides raising the cell viability from 91.3 ± 4% to 96.4 ± 4% for 0.0CuO@CA, and 12.0CuO@CA, respectively, thereby implying that the fabricated CuONPs@CA nanocomposite has biocompatibility towards fibroblast cells. Thus, introducing biological activity into CA nanofibers via loading with CuONPs makes it suitable for numerous biomedical applications, particularly as an environmentally benign wound dressing fibers., (Copyright © 2021. Published by Elsevier B.V.)

This paper studies the use of zinc oxide nanoparticles (ZnO-NPs) synthesized using an extract of Convolvulus arvensis leaf and expired ZnCl 2 , as efficient inhibitors of carbon steel corrosion in a 1 M HCl solution. The synthesized ZnO-NPs were characterized by Fourier-transform infrared (FTIR) and UV-Vis spectroscopy analysis. The corrosion inhibition of carbon steel in 1 M HCl was also investigated through potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and the determination of weight loss. The results show that the efficiency of the prevention increased when the concentration of ZnO-NPs was increased to 91%, and that the inhibition efficiency was still high (more than 89%) despite decreasing at high temperatures, acting as a mixed-type inhibitor. A sample of carbon steel with a protective layer of inhibitor on top was observed during immersion in 1 M HCl for 20 h; an increase in the charge transfer resistance (R ct ) and stability of the inhibitor could be observed after 6 h. Adsorption isotherm models demonstrated that the inhibitor adsorption mechanism on the carbon steel surface followed Langmuir rather than Freundlich and Temkin behaviors. The thermodynamic parameters showed that the adsorption process is one of mixed, spontaneous, and exothermic adsorption. The results illustrate that the ZnO-NPs were a strong inhibitor of carbon steel corrosion in acid medium. The results of scanning electron microscopy (SEM) images showed that the ZnO-NPs formed a good protective film on the carbon steel surface.

The adsorption of fluorescein dye (FD) on wild herb microparticles ( Juniperus (JH) and Solenostemma argel (Del) Hayne (SH)) was studied to elucidate the changes in adsorption behavior with various parameters, such as initial concentration, adsorbent dosage, pH, contact time, and temperature. It was determined that the adsorption percentage of JH for FD was as high as 85.5%, which was higher than that of SH (71.9%). The morphologies of JH and SH were analyzed using Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM) analyses. The JH and SH adsorbents contained different functional groups, which were involved in the binding of the FD molecules during adsorption. The XRD patterns of JH and SH confirmed the presence of a combination of amorphous and crystalline phases in their structures. The SEM images of the surface of JH revealed the presence of deep pores ranging in size from 1.9 to 3.5  μ m, while SH contained smaller pores ranging in size from 130 to 350  μ m, which could help absorb large quantities of FD. The Freundlich model fitted the adsorption isotherms better than the Langmuir model. The values of the Freundlich equilibrium coefficient and separation factor ranged from 1 to 2 and from 0 to 1, respectively. The maximum adsorption capacities of JH and SH were determined to be 2.91 and 2.565 mg/g, respectively. Four kinetic models were used to analyze the experimental data, and it was determined that the pseudo-second-order kinetic model best described the adsorption process, which involved chemical adsorption and the internal diffusion. Thermodynamic parameters, including the enthalpy, entropy, and Gibbs free energy, were calculated. These parameters indicated that the adsorption of FD on JH was spontaneous and endothermic and the adsorption of FD on SH was unspontaneous and exothermic., Competing Interests: The authors declare that there are no conflicts of interest regarding the publication of this article., (Copyright © 2020 Ghadah M. Al-Senani and Nada S. Al-Kadhi.)

Wild herbs ( Origanum ( OR ) and Lavandula ( LV )) were used as environment-friendly adsorbents in this study. The adsorbents were used for adsorption of Cu and Ba from water. The adsorption of heavy metals onto OR and LV was dependent on particle size, dose, and solution pH. The diameter of adsorbent particles was less than 282.8 nm. The adsorption follows second-order kinetics. Langmuir and Freundlich models have been applied to describe the equilibrium data, and the thermodynamic parameters, the Gibbs free energy, ∆ G °, enthalpy, ∆ H °, and entropy, ∆ S °, have been determined. The positive value of ∆ H ° suggests that the adsorption of heavy metals by the wild herbs is endothermic. The negative values of ∆ G ° at all the studied temperatures indicate that the adsorption is a spontaneous process. It can be concluded that OR and LV are promising adsorbents for the removal of heavy metals from aqueous solutions over a range of concentrations.