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Wastewater arising from pharmaceutical manufacturing industries typically carries elevated levels of toxic organic and inorganic compounds, both biodegradable and non-biodegradable, in addition to pharmaceutical residues. The pharmaceutical industry is characterized by its considerable diversity, encompassing multiple divisions such as chemical synthesis, fermentation, biological, or natural extraction, and compounding or formulation and the wastewater generated from these divisions' exhibits significant variations in composition. Since pharmaceutical residues are characteristic refractory organic molecules in water, they are hazardous to humans and the ecosystem, making them a priority contaminant. Advanced Oxidation Processes (AOPs) offer the ability to treat pharmaceutical wastewater. In this paper, manufacturing processes adopted in pharmaceutical industry and chemical and photo chemical AOPs for treatment of wastewater from the industry are critically evaluated. AOPs induced by sulfate and hydroxyl radicals were also discussed. To enhance comprehension of the efficacy of these AOPs, the experimental outcomes of prior research publications pertaining to the elimination of emerging pollutants have been compiled under every area. The review will give insights for the pharmaceutical industry wastewater treatment and subsequently help the industry to choose the best treatment method. The combination of AOPs are more effective at removing emerging pollutants in terms of higher degradation efficacies. HIGHLIGHTS: The presence of pharmaceutical residues in domestic wastewaters poses a risk of genotoxicity, resistance to pathogenic bacteria, and aquatic toxicity. The extensive diversity within the pharmaceutical industry, comprises various sectors like chemical synthesis, fermentation, natural extraction, and formulation. Chemical synthesis, fermentation, natural extraction, and formulation are extensively discussed to treat pharmaceutical industrial wastewater effectively. AOPs present an alternative to conventional wastewater treatment techniques because of their broad applicability, quick processing, and capacity to totally convert contaminants into nontoxic end products, rather than only completing intermediate steps. Compared to individual AOPs, a combination AOPs are more effective at removing refractory pollutants because some of their drawbacks can be overcome. [ABSTRACT FROM AUTHOR]

The composition and concentration of a low-molecular organic additive, leading to a significant improvement in the electrical properties of low-density polyethylene of high pressure grade 10,803-020, were experimentally determined. Phthalic anhydride and phthalic acid were used as modifying organic additives. The content of additives in the polyethylene of high pressure composition varied in the range of 0.01–0.1 wt%. It has been shown that the content of 0.05 wt% phthalic anhydride and phthalic acid in the composition polyethylene of high pressure (PEHP + 0.05 wt% PhAn + 0.05 wt% PhAc) is the optimal composition, since the electrical strength of the film has increased significantly. The dependences of the dielectric loss tangent and specific volumetric electrical resistance on temperature, as well as the kinetics of physicochemical changes in them under the influence of electrical discharges in air and UV irradiation, have been studied. It was established that the dielectric characteristics of the polymer composition PEHP + 0.05 wt% PhAn (storage life 40 years) changed slightly. [ABSTRACT FROM AUTHOR]

The time-dependent graphene oxide (GO) reduction in medium vacuum under ultraviolet (UV) irradiation at 365 nm has been investigated. We found that GO exposed to UV at room temperature and at a vacuum of about 10−1 mbar shows a notable oxidation for irradiation times up to about 60 min followed by a successive reduction up to 210 min. Characterization measurements have been performed mainly using the Attenuated Total Reflectance (ATR) Fourier Transform Infrared (FTIR) and Raman spectroscopies. ATR-FTIR spectra, acquired in the (400–4000) cm−1 wavenumber range, have indicated an initial decrement of the IR transmission (oxidation process) with the exposure time up to about 60 min and a successive increase of the IR transmission (reduction process) for greater irradiation times up to 210 min. The IR transmission bands are attributed to the oxygen functional groups contained in GO which increase for low UV exposure times and gradually disappear during the UV-induced reduction process. Raman spectra confirm this interpretation showing a decrease of the AD/AG ratio value, with respect to the GO virgin value, for low UV exposure times and an increase for greater times. The GO oxidation and reduction processes, due to the UV GO treatment in medium vacuum conditions, have been also verified by energy dispersive X-ray fluorescence and surface wettability measurements. [ABSTRACT FROM AUTHOR]

The present work deals with the optimization of basic fuchsin dye removal from an aqueous solution using the ultraviolet UV/H2O2 process. Response Surface Modeling (RSM) based on Box-Behnken experimental design (BBD) was applied as a tool for the optimization of operating conditions such as initial dye concentration (10–50 ppm), hydrogen peroxide dosage (H2O2) (10–20 mM/L) and irradiation time (60–180 min), at pH = 7.4 under ultra-violet irradiation (254 nm and 25 W intensity). Chemical oxygen demand (COD abatement) was used as a response variable. The Box–Behnken Design can be employed to develop a mathematical model for predicting UV/H2O2 performance for COD abatement. COD abatement is sensitive to the concentration of hydrogen peroxide and irradiation time. Statistical analyses indicate a high correlation between observed and predicted values (R2 > 0.98). In the BBD predictions, the optimal conditions in the UV/H2O2 process for removing 99.3% of COD were found to be low levels of pollutant concentration (10 ppm), a high concentration of hydrogen peroxide dosage (20 mM/L), and an irradiation time of 80 min. [ABSTRACT FROM AUTHOR]

Polymethylmethacrylate (PMMA) has been irradiated by 365 nm UV wavelength at different exposition times in air and room temperature. The macromolecular modifications induced in the polymer have been investigated using attenuated total reflectance (ATR) coupled to Fourier transform infrared (FTIR) spectroscopy, UV-Visible spectroscopy, surface profiler, wetting ability, and electronic microscopy. The observed chemical, optical and morphological changes occurred as a consequence of the UV irradiation suggest that chain scissions are induced by the UV radiations, with reduction of the IR and visible transmittance, wetting ability and surface roughness. The study of the degradation of PMMA by different times of exposure to UV radiation is investigated with the aim of understanding the effects produced over time on optical devices such as intraocular lenses, optical fibres, protective screens, and instrumental lenses. [ABSTRACT FROM AUTHOR]

Recently, smart wormlike micelles (WLMs) that respond reversibly to external environmental stimuli and display tunable rheological properties have attracted considerable interest. However, the surfactants used in the smart WLMs are always commercially unavailable, and specialized organic synthesis is needed. Here, CO2/N2 and light dual stimuli-responsive WLMs can be prepared by CTAB, cinnamic acid (CA), and cetyl dimethylamine (CDA), which are all commercially available compounds. The zero-shear viscosity (η0) of the ternary system (CTAB-CA-CDA-CO2) reaches a maximum value of 530 Pa·s. Furthermore, the system produced a fast response to the dual stimuli of CO2 and UV light, showing a circulatory gel/sol transition, which reflected changes in the self-assembly from entangled worms to spheres or rod-like micelles. The smart WLMs using cheap and commercially available compounds not only avoid complex organic synthesis or purification, but also allow precise control of the WLMs with dual responsiveness, which have a wide range of applications in large scale processes. [ABSTRACT FROM AUTHOR]

The photocatalytic reduction of Cr6+ to Cr3+ in an aqueous solution, using 3 wt% Ag/g-C3N4 in the presence of ethylenediaminetetraacetic acid (EDTA), has been investigated here. The photocatalytic reduction of Cr6+ with pure g-C3N4 was very low. The addition of Ag and EDTA can significantly improve the photocatalytic reduction of Cr6+ using g-C3N4. In the presence of EDTA, the efficiency with Ag/g-C3N4 was better than those with Au/g-C3N4 and Cu/g-C3N4. With EDTA, the reduction rate constant increased from 0.0005 for pure g-C3N4 to 0.12 min−1 for 3 wt% Ag/g-C3N4. By increasing the concentration of EDTA from 0 to 500 mg L−1, the reduction efficiency of Cr6+ increased extremely, and the rate constant raised from 0.008 to 0.12 min−1. The optimal EDTA concentration was 500 mg L−1 for the photocatalyst Ag/g-C3N4. The Ag-EDTA complex may be reduced to metallic silver by the conduction band electrons of g-C3N4. The electron–hole recombination was significantly suppressed by the electron trapping of Ag. EDTA may act in by the formation of Cr3+-complex and the separation of Cr3+ from the g-C3N4 surface and by the valence band hole scavenger of g-C3N4. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), UV–Vis diffuse reflectance spectroscopy (DRS) and photoluminescence spectra (PL) were used to characterize g-C3N4 and Ag/g-C3N4 nanoparticles. A possible mechanism for photocatalytic Cr6+ reduction has also been demonstrated. [ABSTRACT FROM AUTHOR]

To promote the wide application of hydrogen-containing diamond-like films (a-C:H) as solid lubricant materials in aerospace environment, a series of a-C:H, a-C:H doped with Cr elements (Cr/a-C:H) and a-C:H doped with B elements (B/a-C:H) were prepared on the GCr15 steel by non-equilibrium magnetron sputtering technique. The effects of ultraviolet (UV) irradiation on the mechanical and tribological properties of the three DLC films were investigated. UV irradiation was found to cause a decline in hardness and modulus of elasticity, and increased residual stress and surface roughness in all three films. UV irradiation has a minor impact to the coefficient of friction of the three films, but leads to a decrease in wear life. The wear life of Cr/a-C:H films was least affected by UV irradiation. UV irradiation can lead to the breakage of sp3C-H bonds in a-C:H film and B/a-C:H film, resulting in the increase of dangling bonds in the films and the decrease of wear life. In the Cr/a-C:H film, the broken sp3 C-H bond is partially reorganized into sp2 C-H bond, which further exerts the passivation effect of C-H bond, resulting in a smaller decrease in the wear life of the Cr/a-C:H film. [ABSTRACT FROM AUTHOR]

Currently, wound dressing technology is of significant interest in order to avoid undesired effects when burns or skin wounds are treated, especially their risk for microbial contamination and subsequent infection. Silver nanoparticles (AgNPs) have claimed importance as antimicrobial agents. For these reasons, a comparative study of different methods to synthesize electrospun polymeric fibers loaded with AgNPs (Ag+/PCLPVP) such as direct blending, ultraviolet irradiation, thermal treatment, and silver mirror reaction methods were done. The morphology and size of the fibers were investigated using the SEM, where the loading of the AgNPs in the fibers was measured with EDS analysis. FTIR, Raman spectroscopy, XRD, and TGA analysis were applied to measure the physicochemical properties of the fibers. DLS study allowed us to measure the size and surface charge of the obtained materials. The antimicrobial efficiency was carried out against Staphylococcus aureus and Escherichia coli bacteria for 24 h. Cytotoxicity was evaluated with the MTT assay using HFF1 cells. The results showed that the method with the best antimicrobial effect in both bacteria is the UV irradiation conducted before the electrospinning process. The UV radiation method also promotes good distribution efficiency, the physicochemical properties obtained were desirable for wound dressings, and the particle size within nanoparticle interval (~17 nm). Therefore, the most promising method for the preparation of Ag+/PCLPVPbased wound dressings was UV irradiation. [ABSTRACT FROM AUTHOR]

In this study, the yield of gelatin extraction from fish waste was optimized using response surface method. The highest yield was obtained with 0.8% citric acid concentration at 72.95°C for 58 minutes. Then, fish gelatin was modified using ultraviolet radiation to overcome fish gelatin defects including unsuitable rheological properties and low thermo-stability. UV irradiation can create crosslinks via alkyl or phenyl groups of the proteins. The modified sample also showed the highest melting point due to the creation of cross-links and improved emulsification and foaming properties of fish gelatin through structural modification and increased surface hydrophobicity of gelatin. [ABSTRACT FROM AUTHOR]

This article reports the green synthesis of zinc oxide nanoparticles (ZnO NPs) by using the aqueous leaf extract of Trema orientalis (L). The ZnO NPs were synthesised by using zinc nitrate hexahydrate acts as the precursor and leaf extract acts as the reducing and capping agent. The synthesis of ZnO NPs was confirmed by the powder X-ray diffraction (XRD) analysis and the average crystalline size was calculated by Scherrer's formula (24 nm) and as well as Williamson-Hall (W-H) equation (26 nm). The Dynamic Light Scattering (DLS) analysis showed the stability and particle size of approximately 65–67 nm of the synthesised ZnO NPs. The Fourier Transform Infrared Spectroscopy (FTIR) analysis confirmed the presence of various functional groups in the synthesised NPs. The UV absorption wavelength is observed at 370 nm, and the calculated direct band gap was found to be 3.13 eV. The surface morphology, the crystalline shape of the synthesised ZnO NPs was determined by using Scanning Electron Microscopy (SEM). The effectiveness of the ZnO NPs on photocatalytic degradation of zoxamide, a benzamide class of fungicide was tested under UV irradiation (λ max ≥ 250 nm). The calculated half-lives of photodegradation of zoxamide in acetonitrile/water solvent system were found to be in the range of 4.09 − 10.46 h. Moreover, the effect of pH, the initial concentration of zoxamide and photocatalyst ZnO NPs dosage were investigated. The experimental kinetic data followed the pseudo-first-order model. The reaction rate constant (kobs) was decreased from 0.1695 to 0.1511 h−1 with increasing initial zoxamide concentration from 120 to 260 mg/L, respectively. Langmuir–Hinshelwood (L–H) kinetic model was proposed for the rate equation of the zoxamide degradation in presence of ZnO NPs under UV irradiation. [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbons (PAHs) entering into soils via sewage sludge could be posing arresting environmental risks. Photocatalytic remediation has been considered as a powerful tool of degrading PAHs in soils. In the present study, a synthesized nanometer mixed-crystal TiO2 was employed to investigate its effects on PAHs degradation in soils by Ultra Violet (UV).Two typical substances of PAHs widely detected in sewage sludge (phenanthrene and pyrene), were added into soils from farmland to provide polluted soil for a series of simulated experiments. These polluted soil samples were mixed with five different levels of the synthesized TiO2 (0, 1%, 2%, 3%, and 4%, wet weights) and the decreases of PAHs under different conditions were compared. The results showed that among the five treatments, the activities of the synthesized photocatalysts followed the order of 0<1%<2%<4%<3%, and the 3% of TiO2 addition was determined as the optimum condition. Moreover, it was found that the degradation of PAHs could increase with the increasements of H2O2, photon flux, and humic substances in treated soils. Our findings supports the perspective of using nanometer synthesized mixed-crystal TiO2 in the degradation of PAHs in contaminated soils by sewage sludge addition and provides hints on understanding the mechanism of developing photocatalytic remediation in PAHs-contaminated soils. [ABSTRACT FROM AUTHOR]

The effect of ultraviolet (UV) irradiation on gas permeability and mechanical properties of low-density polyethylene (LDPE) films was investigated in the temperature range from 20°C to 60°C. It was shown that UV exposure of the films resulted in their artificial aging, which is manifested as a decrease in gas permeability and as a variation in structure and mechanical properties of the LDPE films. A correlation between gas permeability and mechanical characteristics of the LDPE films subjected to the action of temperature and UV irradiation was found. The novelty of the performed investigations is due to the fact that the gas permeability of polymers exposed to the combined effects of UV radiation and temperature has not been studied so far. [ABSTRACT FROM AUTHOR]

Encapsulation of LiCl (LiCl derivatives) in porous Au-coated PET membranes after UV irradiation or thermal annealing was studied by ion and neutron beam analytical techniques. The shape of the pores in the PET membranes before and after LiCl doping were characterized by Ion Transmission Spectroscopy that enabled to describe their 3D geometry and filling after exposing to a LiCl aqueous solution. The content and depth distribution of Li (and Cl) in pores was examined by Neutron Depth Profiling (NDP). Using the ITS and NDP complementary methods, it was possible to determine the amount of lithium incorporated in the pores and assess the ability of the PET membranes (modified by UV irradiation or thermal annealing) to encapsulate lithium atoms (LiCl derivatives). The present study could be relevant to technology of porous separators for thin lithium ion batteries. [ABSTRACT FROM AUTHOR]

Photosensitized degradation of phenanthrene and pyrene using humic acid (HA) was applied for remediation of PAHs. The desired dosages of HA (0, 10, 20, 30, and 40 mg kg−1) were added into the PAHs contaminated soil, and soil samples were randomly located in photodegradation chamber under the UV lamps for 25 h. The results suggested that the photosensitized degradation of phenanthrene and pyrene obeyed the pseudo-first-order kinetics. Moreover, the increased concentration of O2, H2O2 and light intensity enhanced the fast degradation of phenanthrene and pyrene. All the results disclosed that HA-assisted photosensitized degradation of PAHs was an available choice for remediation of PAHs polluted soil in the practice. [ABSTRACT FROM AUTHOR]

In the present study, the photochemical degradation of amoxicillin and total organic carbon (TOC) removal in pharmaceutical aqueous solutions was studied using UV irradiation, titanium dioxide, hydrogen peroxide and iron in a batch photoreactor operated for 120-150 min. The effect of the initial concentrations of the target compound, hydrogen peroxide and ferric ions and of their combination was examined. It was found that under direct UV photolysis, considerable TOC removals were obtained only when the initial concentration of amoxicillin (AM) was below 100mg/L. For initial concentration of AM 250 mg/L, the TOC removals achieved were of no practical use (below 5%). The TOC removals achieved in the presence of TiO2 were lower than 20% in all cases. In the presence of hydrogen peroxide in the range of 12.2-146.9 mmol/L and initial AM concentration 250 mg/L, for increasing H2O2 concentrations higher TOC removals were achieved up to the concentration of 73.4 mmol/L H2O2. The presence of even very small amounts of Fe(III) in the solution resulted in significantly increased TOC removals; 2.2 times higher than without Fe(III) after 120 min. Fe(III) presence accelerated dramatically the process during the first 60 min. The origin of Fe(III) ions was not important since practically the same results were obtained whether FeCl3 or Fe(NO3)3 was used as source of ferric ions. Adjusting the initial concentrations of AM, Fe(III) and H2O2, TOC removals above 90% were achieved. [ABSTRACT FROM AUTHOR]

The photocatalytic reduction of toxic Cr(VI) to non-pernicious Cr(III) using ZnFe2O4/EDTA (ethylenediaminetetraacetic acid) under UV irradiation was evaluated. The reduction of Cr(VI) with bare ZnFe2O4 under UV irradiation was negligible. However, the Cr(VI) in the solution was completely reduced within 3 h after the introduction of EDTA. EDTA could consume valence band holes and could be oxidized by holes into inorganic products. Therefore, photo-generated electrons could be used to reduce Cr(VI) to Cr(III). The effect of concentration of EDTA, ZnFe2O4 photocatalyst dosages, and initial pH on the photocatalytic reduction of Cr(VI) was investigated. The results revealed that the photocatalytic reduction of Cr(VI) accelerated by increasing EDTA concentration and ZnFe2O4 dosage. The present reduction process confirms the pseudo-first-order kinetic reaction. The quasi reduction rate constant increased from 3.5 x 10−4 min−1 to 2.6 x 10−2 min−1 with the increase in initial EDTA concentration from 0 to 1000 mg L−1. The acidic solution is preferable for the photocatalytic reduction of Cr(VI). The entire reduction of Cr(VI) was carried out within 2 h under the optimum conditions with pH 2, 20 mg ZnFe2O4, and 500 mg L−1 EDTA. The formation of [Cr–EDTA]3+ complex may be advantageous to accelerate the Cr(VI) reduction. A probable mechanism for the photocatalytic Cr(VI) reduction was speculated here. [ABSTRACT FROM AUTHOR]

The blends of synthetic and natural polymers are extensively investigated as materials for medical applications. Synthetic component usually ensures appropriate mechanical and physical properties while biopolymer improves biocompatibility of the material. In our work, we decided to use poly(vinyl alcohol) (PVA)—water-soluble, chemically stable, elastic polymer and elastin—a fibrous protein present in the extracellular matrix of connective tissues. The aim of our work was to study the influence of UV light on spectroscopic properties of poly(vinyl alcohol)/elastin hydrolysates blends. PVA is a rather photostable polymer while elastin possesses various chromophores in the structure capable of absorption of light λ > 200 nm. As a result of the blending, some interactions between the synthetic and biological components occur and cause the changes of photochemical stability of the new material. Our study demonstrates that the poly(vinyl alcohol)/elastin mixtures are more sensitive to UV irradiation than both components separately. [ABSTRACT FROM AUTHOR]

The reduction of ammonia emissions from air was experimentally investigated by advanced oxidation processes (AOPs) utilizing the combination of ultraviolet irradiation with ozone. The influence of operating conditions such as initial ammonia concentration and flow rate of gas on the reduction of ammonia concentration was investigated in homemade photochemical unit. The conversion of ammonia decreased with increasing initial concentration of ammonia and with increasing flow rate of air (decreasing retention time). The highest conversion of ammonia (97%) was achieved under lower initial concentration of ammonia (30 ppm) and lower flow rate of air (28 m3/h). The energy per order was evaluated for the advanced oxidation process too. The energy consumption was about 0.037 kWh/m3/order for the 97% ammonia conversion at 30 ppm of initial ammonia concentration and 28 m3/h flow rate of air. Based on the results, the advanced oxidation process combining the UV irradiation and ozone was effective for mitigation of ammonia concentration and presents a promising technology for the reduction of odor emissions from livestock buildings. Moreover, the AOPs are suitable for application for high flow rate of air, especially for ammonia abatement from livestock buildings, where very high efficiency is expected. [ABSTRACT FROM AUTHOR]

Interpenetration of dielectric elastomers with fillers is an effective technique to improve requisite properties for voltage induced electromechanical performance. However, the requirement that the rigid frame has to maintain its pre-strained state, and time/temperature related phenomenon like stress relaxation/concentration, strain-induced crystallization and void propagation etc., limits this technology. To overcome these limitations, thermochemical and UV irradiation techniques of polymerization are used to modify the macromolecular structures of VHB 4910 elastomer with crosslink monomers. Both the methods are compared in terms of the modification in surface and molecular structure through optical microscope and infrared spectroscopy, respectively. Thermochemically modified samples are found flawless with regular surface reformation; crosslink density is evaluated and its influences on hysteresis, dielectric constant and material degradation at elevated temperature are characterized. Results from this study may contribute towards the complete understanding of space density for inclusion of filler, used for material development with user-defined properties. [ABSTRACT FROM AUTHOR]

Novel membranes consisting of polyvinyl alcohol (PVA), cellulose nanocrystals (CNCs), nanosilica (NS), glutaraldehyde (GLA) and glycerine (G) were prepared using a compression moulding process. Rice husk is selected to isolate pure cellulose nanocrystals via mechanical and chemical treatment. The biodegradability of the membranes has been evaluated using UV accelerated weathering as well as a soil burial test. The chemical structure of the membranes were characterised by Fourier-Transformation Infrared (FTIR) spectroscopy. The microstructure of the membranes was characterised by using Scanning Electron Microscope (SEM). The mechanical properties of the membranes were evaluated using standard techniques. The swelling and weight loss resulting from biodegradation were also evaluated. The results showed that the developed membranes can be used as food packaging bags owing to biodegradability (weight loss) under irradiation and during soil burial. The membranes are environmentally friendly. [ABSTRACT FROM AUTHOR]

The surface plasmon resonance research of manufactured highly homogeneous ultrathin polysulfone films was performed, which were exposed to the short-wave (254 nm) UV irradiation of various durations. Surprisingly, the resonance incident angle and dielectric constant increase after short-term UV irradiation before the ordinary decrease caused by usual polymer degradation. The experimental results are ascribed to the formation of polar groups leading to orientation of chain fragments of intermediate length followed by their breaking and formation of mobile short fragments under longer times of irradiation. [ABSTRACT FROM AUTHOR]

In this study, it is aimed to prepare polyvinyl borate (PVB)/titanium dioxide (TiO2) composites through the condensation reaction of polyvinyl alcohol and boric acid in the presence of TiO2 nanoparticles. The scope of this study contains the photocatalytic activity of the prepared composites with varying TiO2 content from 0 to 35 wt.% for the degradation of methylene blue in aqueous medium under UV light irradiation. The structure and morphological properties of the prepared composites were studied with FTIR, TGA, EDX, SEM and TEM analyses. The photocatalytic activity of the prepared samples was analyzed by UV-Vis spectrophotometer measurements. In parallel with TiO2 content up to 30 wt.%, the photocatalytic activity of PVB/TiO2 composites was enhanced and the composites exhibited higher discoloration rate of the model dye, methylene blue. [ABSTRACT FROM AUTHOR]

Hydrophilicity of Nylon-6 fabrics has been modified by surface coating with aqueous solution of carboxymethyl cellulose and acrylic acid (AAc) using UV irradiation. The effect of AAc concentration and UV irradiation time (minute) on the hydrophilic properties of the coated nylon fabric was studied. Water absorption (%) increased with increasing AAc concentration up to 20% at 20 min. Morphology of coated fabrics was examined by scanning electron microscope, which indicated compatibility between coating layer and fabrics. Moreover, mechanical properties in terms of tensile strength and elongation at break were studied. The sorption of dyestuffs such as basic, and reactive and also, sorption of metal ions by coated fabrics was measured using UV Spectrophotometer. The results showed that the coated fabrics have a high affinity for basic rather than reactive dye. Also, coated fabrics show good efficiency toward metal ions such as Cu2+, Ni2+, and Co2+. The results obtained show that the coated nylon fabrics have good sorption ability toward heavy metal ions and dyes. [ABSTRACT FROM AUTHOR]

Imidaclopride is an insecticide widely used for pest control in agriculture around the world. It acts on the central nervous system of insects, while posing lower toxicity to mammals. This is an organic material made of Pyridinium, Dihydroimidazol and Nitramide. This structure poses a threat to the environment and humans. Until now, different types of methods have been used for elimination of this organic pollution. Recently, advanced oxidation processes (AOPs) are presented as a proposed method to remove this organic pollution. Photocatalytic degradation is also used as an efficient method for destruction of organic structures. In this study, the effect of titanium dioxide (TiO2) nanoparticle as a photocatalyst activated by UV irradiation is investigated. The new design of the reactor was prepared with coaxial cylinders in which the inner cylinder is rotated at a constant speed. The reactor worked in two batch and continuous modes. The results show that the UV irradiation is more effective than activated TiO2nanoparticle, as the designed reactor with UV irradiation eliminated Imidaclopride in less than 2 hours. [ABSTRACT FROM AUTHOR]

TiO2/Zr nano photocatalyst is obtained with various trace amount of Zr by employing the sol-gel method. Several spectroscopic techniques are applied to characterize the structures and properties of nano photocatalyst. It is found that the effect of doping Zr ions to the TiO2 lattice led to improving the surface properties and decreasing the particle size of nano photocatalyst. Therefore, it causes increasing specific surface area and photocatalytic activity as compared with pure TiO2. The photocatalytic activity of the nano photocatalyst is employed for the degradation of Methyl Orange as organic waste in the aqueous solution under UV irradiation in a batch reactor. [ABSTRACT FROM AUTHOR]

We report the study of optical textures and director configurations within nematic-in-water microdroplets of the liquid-crystalline mixtures based on azoxybenzene and cyanobiphenyl (as a polar dopant). Both pure azoxybenzene and polar dopant materials exhibited bipolar configuration within liquid-crystalline droplets, whereas their mixtures at appropriate concentrations spontaneously formed radial droplets. It was found that increasing of the dopant's concentration resulted in the forward tangential-homeotropic and reentrant homeotropic-tangential anchoring transitions. We also triggered bipolar-to-radial structural transition by UV irradiation providing trans-cis isomerisation of nematogens. Critical irradiation time needed for radial configuration formation was found to decrease with concentration of polar dopant. Mesoscoping modelling is proposed to explain main experimental results. The presented data are discussed for chemical and biological sensing applications. [ABSTRACT FROM AUTHOR]

In this work, we investigate the effect of UV light irradiation on the dielectric parameters of the nematic liquid crystal (5CB) containing dispersed ZnO nanoparticles. With addition of nanoparticles, nematic LC's are promising new materials for a variety of applications in energy harvesting, displays and photonics including the liquid crystal laser. To realize many applications, however one must optimize the properties of liquid crystal and understand how UV light irradiation interacts with the nanoparticles and LC molecules in dispersed/doped LC. The dielectric permittivity and loss factor are discussed for the pure nematic LC and dispersed/doped system after, during and before UV light exposure. Dielectric relaxation spectroscopy was carried out in the frequency range 100 Hz-10 MHz in the nematic mesophase. [ABSTRACT FROM PUBLISHER]

Metal oxide semiconductor gas sensors operating under UV irradiation have been validated for detection of variety of chemicals in wide ranges of concentrations at room temperature. This article reviews recent advances in UV-activated metal oxide gas sensors in general and outlines the operating principles and sensing performance of UV-LED based sensors in particular. The sensing properties of several metal oxide semiconductors such as ZnO, TiO2, SnO2, In2O3, and metal oxide composites under UV-LED irradiation are individually presented and their advantages and shortcomings toward various gases are compared. Moreover, it is demonstrated that for the UV-LED based gas sensors, the performance can be improved by optimizing the sensor platform design and UV source parameters such as wavelength and power intensity. Further, it is illustrated that the gas sensing selectivity can be tuned by modifying the semiconductor layer structure or adjusting appropriate wavelength to an optimal value. [ABSTRACT FROM AUTHOR]

Objective:Aim of this work was the synthesis of a methacrylic hyaluronic acid (HA) derivative and the production, via photocrosslinking, of related hydrogels loaded with an endopeptidase intended for a potential oral treatment of celiac disease. Methods:The methacrylic derivative of HA was prepared through a one-pot procedure involving the reaction with ethylenediamine (EDA) and methacrylic anhydride (MA). The obtained derivative, named HA-EDA-MA, was used to prepare photocrosslinked hydrogels loaded with a prolyl endopeptidase derived fromFlavobacterium meningosepticum(PEP FM) able to detoxify gliadin. Obtained hydrogels were recovered as gels or freeze-dried powders. Results:Hydrogels obtained as freeze-dried powders, are able to protect loaded enzyme from degradation due to freeze-drying process and from alteration during storage, overall in the presence of a cryoprotectant. All photocrosslinked HA-EDA-MA hydrogels (gels and powders) release PEP FM in simulated intestinal fluid in sustained manner and in active form. HA-EDA-MA hydrogels are nontoxic as demonstrated throughin vitrostudies on BALB 3T3 cells. Conclusions:Prepared hydrogels show a potential application for oral treatment of celiac disease thanks to the possibility to release enzymes able to detoxify the gliadin peptide that induces the immunogenic response. [ABSTRACT FROM AUTHOR]

Whereas green tea has historically been consumed in high quantities in Northeast Asia, its popularity is also increasing in many Western countries. Green tea is an abundant source of plant polyphenols exhibiting numerous effects that are potentially beneficial for human health. Accumulating evidence suggests that green tea polyphenols confer protective effects on the skin against ultraviolet (UV) irradiation-induced acceleration of skin aging, involving antimelanogenic, antiwrinkle, antioxidant, and anti-inflammatory effects as well as prevention of immunosuppression. Melanin pigmentation in the skin is a major defense mechanism against UV irradiation, but pigmentation abnormalities such as melasma, freckles, senile lentigines, and other forms of melanin hyperpigmentation can also cause serious health and aesthetic issues. Furthermore, UV irradiation initiates the degradation of fibrillar collagen and elastic fibers, promoting the process of skin aging through deep wrinkle formation and loss of tissue elasticity. UV irradiation-induced formation of free radicals also contributes to accelerated photoaging. Additionally, immunosuppression caused by UV irradiation plays an important role in photoaging and skin carcinogenesis. In this review, we summarize the current literature regarding the antimelanogenic, antiwrinkle, antioxidant, and immunosuppression preventive mechanisms of green tea polyphenols that have been demonstrated to protect against UV irradiation-stimulated skin photoaging, and gauge the quality of evidence supporting the need for clinical studies using green tea polyphenols as anti-photoaging agents in novel cosmeceuticals. [ABSTRACT FROM AUTHOR]

In this research, we studied the phototransformation of 2,4,6-tribromophenol (TBP) by UV irradiation in aqueous solution. Effects of typical environmental factors (i.e., pH and the initial concentration of TBP, Fe3+and NO2−) were also investigated. Results showed that the transformation process followed pseudo-first-order kinetics. The transformation rate constant of TBP decreased with increasing initial concentration and increased with increasing Fe3+and NO2−concentrations as well as increasing pH. Ten photoproducts were tentatively identified after irradiation of TBP, according to HPLC-LTQ-Orbitrap MS and GC/MS analysis. Among them, two dihydroxylated dibromobenzene compounds (di-OH-DBB) were found to be predominant over the reaction time, indicating that hydrodebromination of TBP could be the main phototransformation mechanism. In addition, the identification of eight OH-PBDEs and di-OH-PBBs suggested that photodimerization might also be a reaction pathway for TBP photochemical reactions. [ABSTRACT FROM PUBLISHER]

Polycarbonates (PC) are widely used in daily life as commodity plastics and it is a critical material regarding to the public health for the consequences that may arise especially for infants due to usage in baby bottles. Therefore, understanding the behavior of PC within the degradative environment is vital. In this study, degradation of polycarbonate via UV-C irradiation was studied within atmospheric and aquatic environments. Mechanical, morphological, thermal tests NMR, TGA, SEM, DSC, Extensometer, Yellowness Index, FTIR and HPLC tests of samples irradiated with different irradiation periods within these two environments were carried out. The analysis results have shown that for both of aquatic and atmospheric environments, the degradation and morphological changes were occurred. Structure tests results show that the main degradation occurred on the carbonate group of PC. In addition, significant amount of Bisphenol A was detected via HPLC analysis in the aquatic solution after irradiation in aquatic environment that could be hazardous for the public health. [ABSTRACT FROM AUTHOR]

This investigation highlights rationale of vaporized solvent bonding for fabrication of transparent polymers such as polymethyl methacrylate (PMMA) in terms of optical transparency and bond strength. Vaporized solvent bonding is employed to fabricate the polymer, and its bonding characteristics with appropriate solvents are analyzed. It is observed that chloroform exhibits superior bonding characteristics in comparison with other solvents such as acetone, ethanol, and dichloromethane. In order to see the effect of prior surface modification carried out by ultraviolet (UV) irradiation and low-pressure plasma, surface energy of the polymer was estimated. It is observed that due to surface modification of PMMA by UV irradiation and low-pressure plasma, surface energy of the polymer increases considerably. However, due to exposure under UV irradiation and low-pressure plasma, molecular weight of PMMA decreases and atomic force microscopy (AFM) studies reveal that the topography of PMMA changes significantly resulting in deterioration of vaporized solvent bonding strength. Therefore, in the case of vaporized solvent bonding, increase in surface energy of the polymer is not a primary factor rather retention of molecular weight is more necessary. [ABSTRACT FROM AUTHOR]

Spherical bridged polysilsesquioxane nanoparticles with thiol groups (BPS-SH) were prepared by the reduction of BPS with disulfide groups after the base-catalyzed hydrolysis and condensation reaction of bis(triethoxysilylpropyl)disulfide. The average size of BPS was around 100∼300 nm. Hydroxyethyl methacrylate (HEMA)-initiated polycaprolactone (PCL) was synthesized by ring-opening polymerization of caprolactone under the co-initiation of HEMA and Sn(Oct)2. New nanocomposites of BPS-SH and HEMA-PCL were fabricated by the photo-induced chemical reaction under a photoradical generator and ultraviolet light. BPS was fully and continuously covered with PCL, which resulted in the rough surface of BPS nanoparticles as well as the connected BPS nanoparticles together. [ABSTRACT FROM AUTHOR]

Fish gelatin was exposed to ultraviolet treatment from 3 to 24 h. Ultraviolet-treated fish gelatin, after 6 h exposure exhibited the highest increase in gel strength. It was shown that doses above 9 h on tilapia gelatin can gradually decrease the gel strength. Partial insolubility of fish gelatin after more than 3 h of ultraviolet treatment was observed. Ultraviolet treatment did not change the Fourier transform infrared spectra of all ultraviolet-treated fish gelatin and control fish gelatin sample. The distribution of the molecular weights of gelatin treated with 3 to 24 h ultraviolet irradiation remained unchanged. [ABSTRACT FROM AUTHOR]

Carbon fibers-reinforced polyimide composites (CF-PI) were fabricated by means of a hot press molding technique. To contrast the effects of ultraviolet and atomic oxygen irradiation under high vacuum on the tribological properties of CF-PI composites, the friction and wear properties of the composites sliding against GCr15 steel ball before and after irradiation were conducted in high vacuum on a ball-on-disk test rig. The experimental results revealed that CF-PI composites exhibited higher modulus and lower coefficient of friction and worn rate value than pure polyimide under high vacuum. However, the coefficient of friction of composites increased and the worn rate value decreased after ultraviolet or atomic oxygen irradiation, which slightly affected the tribological properties of CF-PI composites. The chemical composition of the composites changed after irradiation was inspected by X-ray photoelectron spectroscopy. Microstructure of the worn surfaces of the tested composites was investigated by scanning electron microscopy to reveal the wear mechanism. [ABSTRACT FROM AUTHOR]

A liquid crystalline dendrimer having a cinnamate mesogen containing an azobenzene moiety (D-6AC2) was prepared as an alignment agent of nematic liquid crystals for a planar homogeneous alignment.D-6AC2is a thermotropic liquid crystal showing smectic phases. A mixture of ZLI-4792 with 1wt% ofD-6AC2exhibited a homeotropic alignment. After UV irradiation of the same sample, the schlieren texture due to a planar orientation was observed, and the texture was maintained even after 133 days. ThusD-6AC2can induce the stable planar alignment of NLC upon UV irradiation. Furthermore,D-6AC2could induce a planar homogeneous alignment by polarized UV light irradiation. [ABSTRACT FROM AUTHOR]

Interpenetrating network (IPN) beads composed of alginate and poly(vinyl alcohol)-epoxypropoxy coumarin (PVA-EPC) conjugate were prepared by dropping the mixture solution into CaCl2 solution under UV irradiation (λ = 365 nm). EPC residues of PVA-EPC could readily be dimerized by λ = 365 nm and de-dimerized by λ= 254 nm even in the presence of alginate. In addition, the viscosity of the mixture solution increased with the time of UV irradiation due to the photo-dimerization. The percentage release in 360 min of FITC-dextran loaded in the beads, which were prepared using the mixture solutions of which alginate/PVA-EPC concentrations were 0.5%/0.5%, 0.5%/1%, and 0.5%/2.5%, were about 2%, 11%, and 5%, respectively. Interestingly, in case of beads prepared using the mixture solution of which alginate/PVA-EPC concentration was 0.5%/2.5%, the release was a little but significantly promoted by the irradiation of λ= 254 nm. [ABSTRACT FROM AUTHOR]

The degradation of atrazine in aqueous solution by UV or UV/H2O2processes, and the toxic effects of the degradation products were explored. The mineralization of atrazine was not observed in the UV irradiation process, resulting in the production of hydroxyatrazine (OIET) as the final product. In the UV/H2O2process, the final product was ammeline (OAAT), which was obtained by two different pathways of reaction: dechlorination followed by hydroxylation, and the de-alkylation of atrazine. The by-products of the reaction of dechlorination followed by hydroxylation were OIET and hydroxydeethyl atrazine (OIAT), and those of de-alkylation were deisopropyl atrazine (CEAT), deethyl atrazine (CIAT), and deethyldeisopropyl atrazine (CAAT). OIAT and OAAT appeared to be quite stable in the degradation of atrazine by the UV/H2O2process. In a toxicity test usingDaphnia magna, the acute toxic unit (TUa) was less than 1 of TUa (100/EC50, %) in the UV/H2O2process after 30 min of reaction time, while 1.2 to 1.3 of TUa was observed in the UV process. The TUa values of atrazine and the degradation products have the following decreasing order: OIET> Atrazine> CEAT≈CIAT> CAAT. OIAT and OAAT did not show any toxic effects. [ABSTRACT FROM PUBLISHER]

Ultraviolet radiation (UV) induces a series of morphological and ultrastructural alterations in human epidermis. Alterations observed in irradiated keratinocytes in morphological studies done before were cell retraction with loss of intercellular interactions, surface blebbing, and eventually cell death by apoptosis. The aim of this study was to investigate effect of UV-A, UV-B, and UV-C irradiation on the cytoskeleton of human keratinocytes. Keratinocytes were obtained by exfoliative scrubbing procedure from buccal mucosa of healthy individuals, and treated with UV-A, UV-B, and UV-C radiation. Afterward, treated cell were labeled with anti-alfa-tubulin and anti-human-cytokeratin and analyzed by light and confocal microscopy. The intensity of the cytokeratin labeling was found to be much higher in all irradiated cells than in control cells as observed by light microscope and measured with the Image J program. This measurement showed that with the decrease in the wavelengths of UV irradiation the intensity of the labeling of cells increases. Although the authors expected to find the collapse of microtubules toward the cell nucleus or their rearrangement in UV-treated cells, these alterations were not verified on cell smears labeled with anti-alfa tubulin observed by confocal microscope. When they used electron microscopy to examine in more detail the morphology of irradiated cells, they did not find apoptotic cells, but found features of autophagy in UV-treated keratinocytes. The authors assume that autophagy found as a result of UV radiation of human keratinocytes acts as a cytoprotective mechanism against UV-induced apoptosis. [ABSTRACT FROM AUTHOR]

We report a new method for the detection and measurement of the chirality of liquid crystal compounds. The method is based on the determination of an azimuth of a disclination line in aθ-cell, with the director aligning unidirectionally at one side and circularly at another one. Experimental observation of disclination rotation was performed with a composition of ZLI-4801-0000 liquid crystal and dopants of opposite-sign chirality (R-2011, S-2011, 7-dehydrocholesterol). Dynamic behavior of the disclinaton line was revealed under the influence of continuous illumination by actinic UV radiation. [ABSTRACT FROM PUBLISHER]

A series of composite materials have been prepared through assembly of two natural polymers, attapulgite and silk fibroin, to adjust the slow release performances of diclofenac molecules, a type of non-steroidal drugs. The assembled composite materials have a core-shell structure, with attapulgite composing the core and silk fibroin composing the shell. It has been found that the formation of the core-shell structure can reduce the release rate of diclofenac to a higher extent. When a small amount of ammonium molybdate was introduced into the composite material's silk fibroin layer, different release performances of drug molecules could be produced. In particular, the release performances of drug molecules contained in the assembled composite materials could be adjusted through UV irradiation. Characterization of the assembled composite materials and mechanism researches of release behaviors of the diclofenac molecules have been conducted by PXRD, SEM, IR, elemental analysis, and zeta potential, etc., in this work. [ABSTRACT FROM PUBLISHER]

A detailed study of color change in poly(vinyl chloride) (PVC) sheets due to high intensity ultraviolet (UV) irradiation was undertaken, focusing on the first 50 h of change. Color changes were monitored with a Datacolor check spectrophotometer and compared with a set of controls. Measurements were taken after 1, 3, 5, 10, 15, and 20 h of irradiation, then at 10 h intervals for the next 40 h. Further measurements were conducted at 100, 240, and 480 h. Data were analyzed using the reflectance spectra (350–800 nm) as well as the CIE (International Commission on Illumination) L* a* b* color values (L*, a*, and b* are lightness value, redness-greenness value, and yellowness-blueness value, respectively) and the total color change (ΔE). The majority of color changes were found to occur within the first 50 h. After 50 h, the color change slowed and began to reverse toward 480 h. Surface microstructure properties, such as morphology, surface tension and oxidized products, were characterized to allow a comparison of sensitivity between the color monitoring methods and a comprehensive understanding of the color change. The results show that color evolution was attributable to the competition between the formations of polyene sequences (dehydrochlorination reaction) and their subsequent oxidation (photobleaching), which was slightly different from the behavior under a xenon arc lamp. According to the color behavior and the microstructure analysis a general scheme accounting for the mechanism of ageing behavior of PVC under high intensity UV irradiation is proposed. [ABSTRACT FROM PUBLISHER]

Plastic bags, mostly made of polyethylene, cause pollution as solid waste due to their nondegradable nature. Accelerated degradation, as a solution to mitigate the menace, can be achieved through moisture enhanced photolysis. This study evaluated the effect of three relative humidity environments, i.e., 25%, 40%, and 60% RH, at a constant temperature of 55°C. The effect was studied for ultraviolet (UV) irradiated and nonirradiated samples of polyethylene (PE) films processed under conventional ways. Photodegradation was initiated using ultraviolet irradiation in the ranges (200–300) nm and (300–400) nm for two hours and the effects of subsequent humidity treatment analyzed. Dynamic mechanical analysis was used to measure the dynamic storage modulus to monitor degradation. For nonirradiated samples, there was essentially no change in storage modulus at the three relative humidity environments after 550 hrs. Irradiation in the (300–400) nm range showed faster degradation than for the (200–300)nm range with the highest drop in storage modulus being 67% after 550 hrs. Raising the humidity from 25% to 40% and 60% RH resulted in 41%, 62%, and 67% drop of storage modulus, respectively, at the 550 hrs. [ABSTRACT FROM PUBLISHER]

Nanocomposites, based on ultra high molecular weight polyethylene (UHMWPE) and multiwall carbon nanotubes (CNTs, 0.5 wt.%) were incorporated by solid-state dry mixing and then UV light irradiated. During these treatments, functional chemical groups were induced in both the components. Physical and mechanical tests were performed on the pristine UHMWPE as well as on the nanocomposite to evaluate their features. Experimental results highlighted that the nanocomposite exhibits higher viscosity, wear resistance, and conductivity than the pristine UHMWPE and the non-UV-irradiated nanocomposite. This suggested that the two functionalized components (CNTs and UHMWPE) interact. [ABSTRACT FROM PUBLISHER]

Hybrid composites from rayon fibers (∼2–5 cm size) and polypropylene (PP) were fabricated by using an extruder. Fibre content of the composite was varied from 5–30% by weight and physico-mechanical properties of the composites were measured. Surface morphology as observed by SEM showed good interface adhesion between rayon and PP matrix. Furthermore inclusion of rayon (up to 15% fiber inclusion) in the composite increased tensile, bending and hardness properties. As the fiber content in the composite increased more than 15%, physico-mechanical properties decreased due to the decrease of fiber matrix adhesion. The change of tensile properties due to environmental aging was carried out by keeping the composite under soil for 1 month and tensile properties were measured periodically. The aging result suggests that composites retained about 75% of its original tensile and bending strength even after 1 month soil burial. The modified fibers were also used for the study. As such the fibers were treated with vinyl-trimethyoxysilane and methanol solution and irradiated under UV before being used with PP in extruder. The results showed retardation of the physico-mechanical properties for composites obtained from irradiated rayon fibers than the composites fabricated from non irradiated rayon fibers. [ABSTRACT FROM PUBLISHER]