Irradiated Solutions Research Articles

The Reactivity of Polyethylene Microplastics in Water under Low Oxygen Conditions Using Radiation Chemistry

Polyethylene (PE) is an intensely utilized polymer, which has consequently led to it becoming a common environmental contaminant. PE and other plastic waste are known to be highly persistent in surface waters; however, chemical and physical changes do take place over time, dependent mostly on highly variable natural conditions, such as oxygen (O2) availability. Gamma radiation was used to generate reactive oxygen species, namely hydroxyl radicals, in initially aerated aqueous solutions to simulate the natural weathering of microplastics in waters where there are fluctuations and often depletions in dissolved O2. The headspace of the irradiated PE-containing solutions was probed for the formation of degradation products using solid-phase microextraction (SPME) fibers in combination with gas chromatography mass spectrometry (GCMS). The major species detected were n-dodecane, with trace levels of tridecane, 2-dodecanone, and hexadecane, which were believed to be predominately adsorbed in the PE microplastics in excess of their aqueous solubility limits. Surface characterization by Raman spectroscopy and light and dark field microscopy indicated no change in the chemical composition of the irradiated PE microplastics under low O2 to anaerobic conditions. However, morphological changes were observed, indicating radical combination reactions.

Degradation and toxicity of the antidepressant fluoxetine in an aqueous system by UV irradiation

Fluoxetine (FLU), a selective serotonin reuptake inhibitor, is commonly found in aquatic environments. Ultraviolet (UV) photolysis is widely used to remove certain pharmaceuticals from water and wastewater. The present study aimed to investigate the toxicity of FLU and its transformed products formed during UV photolysis by using zebrafish embryos (Danio rerio) as a model. The degradation rates of FLU for five days were approximately 63.6% ± 2.14%, 84.6% ± 0.99%, and 97.5% ± 0.25% after 15, 30, and 60 min of UV irradiation, respectively. Furthermore, the degradation mechanism was explored using LC-MS measurements and density flooding theory (DFT) theoretical calculations. Comprehensive toxicity preassessment of FLU and its degradation products was carried out using the T.E.S.T. software. The effects of physiological and biochemical parameters and neuron- and apoptosis-related gene expression were examined in zebrafish embryos exposed to non-irradiated (0-min) and irradiated (15, 30- and 60-min) solutions from 4 h post-fertilization (hpf) to 120 hpf. The hatching time of zebrafish embryos exposed to the non-irradiated solution (0-min) and irradiated solution (60-min) was delayed, their heart rate at 48 and 72 hpf increased, and their body length at 120 hpf decreased. Significant differences were found between the non-irradiated (0-min) and UV-irradiated (15- or 30-min) groups. A dynamic response involving acetylcholinesterase (AChE) and superoxide dismutase (SOD) activity was also observed in the non-irradiated and UV-irradiated groups. During the UV treatment experiments, the expression levels of neuron-related and apoptosis-related genes were significantly reduced over time alongside the formation of FLU degradation products. Overall, this study provides new concepts to remove and assess the toxicity of emerging contaminants in aquatic environments and highlights the need to consider the formation and persistence of toxic transformation products.

Study on the Minimum Bactericidal Concentration (MBC) of Maillard reaction products of Chitosan and Glucosamine prepared by Gamma-irradiation Method

The Maillard reaction products of chitosan and glucosamine (CTS-GA MRPs) were formed by gamma Co-60-irradiation method and determined their minimum bactericidal concentrations (MBC). The mixed solutions of chitosan - glucosamine were irradiated with a dose range of 0-100 kGy to induce the Maillard reaction products (MRPs). The formations of MRPs were determined by spectrophotometric analyses and the contents of remaining glucosamine were evaluated by high performance liquid chromatography (HPLC). The antibacterial activities of CTS-GA MRPs were tested by agar well diffusion test and MBC determination test against both gram negative (Escherichia coli) and positive bacteria (Bacillus subtilis) at acidic and alkaline pH was also carried out. By agar well diffusion test, irradiated CTS-GA solutions were able to form inhibition growth zones on E. coli plate whereas on B. subtilis plate, only CTS-GA MRPs irradiated at 25 kGy expressed this ability. The results of the MBC determination test indicated that CTS-GA MRPs formed at 25 kGy exhibited highly antibacterial activity in pH 5 and even pH 7. Therefore, this CTS-GA MRPs could be used as a promising preservative agent applied for meat and meat-product preservation.

A Comparative Study on Sustainable Dyeing of Silk and Wool with Acid Red 138 Dye

ABSTRACT Environment-friendly textile processing is now-a-days worldwide demand. The current study has been concerned with the utilization of suitable tool i.e. microwave radiation for the improvement of dyeing behavior of natural fabrics using Acid Red 138 dye. Microwave treatment up to 6 min has been given to both dye solution and fabrics. Microwave-treated and un-treated fabrics were used to dye under-treated and un-treated solutions. Different dyeing parameters were employed and shade made at optimized conditions were as per ISO fastness standards and it was found that un-heated silk has given excellent results when dyed at 65◦C for 65 min under irradiated dye solution of 4 pH containing 4 g/100 mL of salt. But irradiated wool has given good results when the solution of 1 pH contaminating 4 g/100 mL salt was irradiated to dye fabrics at 65 ◦C for 65 min. However, silk fabric has shown more promising behavior toward treated dye solution as compared to wool fabric under optimum conditions. It is concluded that microwave treatment has a good potential not only to make acid dyeing process more sustainable for the coloring behavior of silk more than wool under mild condition.

PH-Responsive Hollow Polymeric Microspheres from Irradiated Cyclic Ether Aqueous Solution

Smart hollow polymeric microspheres have been widely applied in various fields such as controlled release, drug delivery, catalysis, and so on. Herein, a facile, green and one-step template-free method is introduced for preparing pH-responsive hollow polymeric microspheres via gamma irradiation of cyclic ether aqueous solution. The hollow polymeric microspheres are synthesized by radiation-induced polymerization and following the self-assembly and self-organization of amphiphilic polymer with cyclic ethers as monomers in water. SEM, TEM, micro-FTIR, and NMR confirmed the morphology and structures of the resultant microspheres. The confocal laser scanning microscope was used to investigate the stimuli-responsiveness and release behavior of hollow microspheres using 1-pyrene carboxaldehyde as a hydrophobic molecule model. The well-defined hollow polymeric microspheres with an average diameter of ca. 2.6 μm or 1.6 μm were prepared directly from dicyclohexal-18-crown-6 or tetraphydropyrane aqueous solution, respectively. The prepared hollow microspheres exhibit obvious pH stimuli-responsiveness and can release the encapsulated hydrophobic molecules when pH is higher than 5.0. Moreover, the reversible morphology transition between hollow microspheres and micelles makes the prepared hollow polymeric microspheres potentially suitable for a wide range of applications, including removal of dyes, oil field engineering, and biomedical fields.

Studying the Effect of Different Parameters on Photocatalytic Degradation of Commercial Safranin-T Dye by Using ZnO/V2O5 Nanocomposite

Photocatalytic-degradation process of Safranin-T dye in this article has been investigated by using prepared nanocomposite and solar lamp. Zinc oxide/vanadium pentoxide nanocomposite was prepared using “hydrothermal processes”. The degradation of dye was performed by irradiated aqueous suspended solutions containing different concentrations of dye using 0.2g/100ml of nanocomposite. The effect of various factors on the photocatalytic-degradation process of Safranin-T dye was tested to reach an optimal state, where they involve the effect of the nanocomposite mass and the effect of Safranin-T dye concentration the effect of light intensity and effect of temperature. The activation energy has been calculated equal 28.84 kJ.mole-1 The irradiated solutions were studied using UV-Vis spectrophotometer.

Accuracy analysis on concentration determination of molecular iodine in gamma irradiated solutions

Accuracy analysis on concentration determination of molecular iodine in gamma irradiated solutions

Effects of Gamma Irradiation on the Extraction Properties of Innovative Stripping Solvents for i-SANEX/GANEX Processes

Recovery of trivalent minor actinides or of the transuranium elements from highly active raffinate could be industrially achieved by innovative Selective ActiNide EXtraction (i-SANEX) and Grouped ActiNide EXtraction (GANEX) processes, respectively. All chemicals involved in the partitioning of actinides must be resistant to acidic and radioactive environments since hydrolysis and radiolysis can have a huge impact on process safety and performance. In this work, the hydrolytic and radiolytic stabilities of two innovative hydrophilic complexing agents, 2,6-bis[1-(propan-1-ol)-triazolyl]pyridine and 2,6-bis[1-(propan-1,2-diol-triazolyl)]pyridine, have been investigated as they proved to be endowed with high actinide selectivity. In order to simulate the damage experienced under process conditions, the stripping solutions were aged in HNO3 for several weeks and γ-irradiated up to 200 kGy with 60Co sources. Batch liquid–liquid extraction tests were performed on fresh, aged, and irradiated stripping solutions in order to verify whether aging and γ-irradiation affect system performance. Furthermore, nuclear magnetic resonance (NMR) analyses were carried out to ascertain the radiation-induced ligand degradation and subsequent byproduct formation. The stripping solutions manifested exceptional performance and radiochemical stability, even under harsh process conditions, to demonstrate their industrial applicability to i-SANEX and GANEX processes.

A mechanistic approach towards the formation of bityrosine in proteins by ionizing radiation – GYG model peptide

One of the methods of protein crosslinking used in the synthesis of protein-based nanoparticles is the formation of bityrosine bridges, which may be achieved by the recombination of phenoxyl-type radicals in irradiated protein solutions. Radiation-induced formation of phenoxyl radicals in tyrosine is promoted in presence of H+. In this work, kinetics of this process and the influence of pH were studied by pulse radiolysis measurements of a model peptide H-Gly-Tyr-Gly-OH (GYG), which may help to solve questions raised for bigger, more complex systems in comparable conditions. The main route of phenoxyl radicals formation consists of the addition reaction of hydroxyl radical to the phenol ring on the tyrosine side-chain and proton catalyzed water molecule elimination. A similar effect was observed in studies of tripeptide solutions containing phosphate buffer. The presented data include time-resolved optical spectroscopy of transient species formed under pulse electron beam irradiation and a comparison of the kinetics of the phenoxyl radicals formation in samples at various pH and in presence of phosphate buffer. The postulated mechanism and obtained values of rate constants of the formation and decay of transient species were additionally checked by simple probabilistic simulations.

Degradation of micropollutant cephalexin by ultraviolet (UV) and assessment of residual antimicrobial activity of transformation products

Cephalexin (CEX) is an antibiotic commonly used to treat bacterial infections in humans and animals. However, it is also a micropollutant. Thus, this study evaluated the degradation of CEX using ultraviolet irradiation (UV-C) and analyzed the by-products as well as their residual antimicrobial activity. A reactor with a mercury vapor lamp was used for the degradation. Irradiated CEX solutions were collected over a period of 4 hours and analyzed using high-performance liquid chromatography coupled with mass spectrometry. For the residual antimicrobial activity the susceptibility test was performed using Staphylococcus aureus and Escherichia coli microorganisms by broth microdilution. It was found that CEX, after treatment, generated a metabolite with a mass of 150 m/z in 15 min. A four- and eightfold increase in the minimum inhibitory concentration of the drug against S. aureus and E. coli could be observed, respectively, after 20 min. Therefore, this treatment proved to be effective in the degradation of CEX, being able to degrade 81% of the initial molecule of the drug in 20 min. Furthermore, the antimicrobial activity of the CEX solution decreased as the irradiation time increased, indicating loss of antimicrobial function of the initial CEX molecule and the resulting by-products.

Optical Characterization of Ciprofloxacin Photolytic Degradation by UV-Pulsed Laser Radiation.

Ciprofloxacin is one of the most prescribed antibiotics in treating bacterial infections, becoming an important pollutant of the wastewaters. Moreover, ciprofloxacin is hard to be destroyed by conventional water treatment processes; therefore, efficient treatments to destroy it are needed in water decontamination. This study offers insights into the performance of 266 nm laser beams on the photodegradation of ciprofloxacin. An Nd:YAG laser was used that emitted 266 nm at an energy of 6.5 mJ (power of 65 mW) and ciprofloxacin water solutions were irradiated up to 240 min. The irradiated solutions were investigated by UV-Vis and FTIR absorption spectroscopy, pH assay, and laser-induced fluorescence. An HPTLC densitometer was used to characterize the laser-induced fluorescence and fluorescence lifetime of photodegradation products. The UV-Vis absorption, FTIR, and laser-induced fluorescence spectra showed the degradation of ciprofloxacin. Moreover, HPTLC densitometry offered the fluorescence and fluorescence lifetime of ciprofloxacin and its three photoproducts as well as their relative quantification. From the FTIR spectra, the molecular structure of two out of three photoproducts was proposed. In conclusion, the laser irradiation method provided the efficient photodegradation of ciprofloxacin, whereas the analytical techniques offered the proper means to monitor the process and detect the obtained photoproducts.

A New Fluorometric Dosimetry for Low-medium Gamma Radiation Doses.

In this study, for the first-time, solutions of a Schiff base was evaluated as a possible chemical dosimeter for gamma-rays at low-medium dose ranges. The solutions of N-N'-bis(salicylidene)-1,3-propanediamine (LH2) were prepared at different ethanol/water compositions and the effect of various irradiation doses on the fluorometric response of these solutions were investigated. Fluorescence spectra of non-irradiated and irradiated solutions showed that fluorescence intensity of LH2 (λex = 375 nm, λem = 498 nm) decreased as the radiation dose increased. This decrease was observed over a wider dose range for the solutions that contain 40-60 % water. In order to increase the sensitivity of the method, LH2-Zn complexes were formed by adding Zn (II) to non-irradiated and irradiated LH2 solutions. After that, analytical parameters such as linearity, LOD, LOQ, repeatability and reproducibility were determined by measuring fluorescence spectra of these solutions (λex = 350 nm, λem = 444 nm). The performance characteristics of the chemical dosimetry system suggest that LH2 can be used as a dosimeter in dose range 0.04-5kGy. The proposed method is simple, sensitive, reproducible and cost-effective, and can be useful in measuring doses in food irradiation.

Investigating the in‐solution photodegradation pathway of Diamond Green G by chromatography and mass spectrometry

AbstractDiamond Green G (CI 42040, Basic Green 1) is a triarylmethane dye mostly employed in the industrial dyeing of miscellaneous natural and artificial textile fibres, in the production of printing inks and as an anti‐fungal agent for aquaculture products. Diamond Green (DG) tends to fade under light irradiation, similar to several other dyes and pigments belonging to the triarylmethane family. In this paper, an in‐solution degradation study was carried out to shed light on DG photostability. The experiments were performed by artificially irradiating DG in water and dimethyl sulphoxide, and analysing aliquots sampled at different time intervals by ultra‐high performance liquid chromatography coupled with diode array detector quadrupole and time of flight tandem mass spectrometry. The degradation products formed were characterised and the product‐ion spectra discussed and interpreted. On the basis of the structure of the identified compounds and their kinetic trend in relation to the accelerated ageing time, degradation mechanisms were proposed for DG, taking into account the role played by the solvent. Finally, the dyeing formulation of an historical textile sample, collected from a stage costume worn in a Zeffirelli lyric opera, was determined utilising the information collected from the analysis of irradiated DG solutions.

Hierarchical Nanocauliflower Chemical Assembly Composed of Copper Oxide and Single-Walled Carbon Nanotubes for Enhanced Photocatalytic Dye Degradation.

We present the fabrication and proficient photocatalytic performance of a series of heterojunction nanocomposites with cauliflower-like architecture synthesized from copper(II) oxide (CuO) nanocrystals and carbon nanotubes with single walls (SWCNTs). These unique photocatalysts were constructed via simplistic recrystallization succeeded by calcination and were labeled as CuOSC-1, CuOSC-2, and CuOSC-3 (representing the components; CuO and SC for SWCNTs, and the calcination time in hours). The photocatalytic potency of the fabricated nanocomposites was investigated on the basis of their capability to decompose methylene blue (MB) dye under visible-light irradiation. Every as-synthesized nanocomposite was effective photocatalyst for the photodecomposition of an MB solution. Moreover, CuOSC-3 exhibited the best photocatalytic activity, with 96% degradation of the visible-light irradiated MB solution in 2 h. Pure CuO nanocrystals generated through the same route and pure SWCNTs were used as controls, where the photocatalytic actions of the nanocomposite samples were found to be remarkably better than that of either the pure CuO or the pure SWCNTs. The recycling proficiency of the photocatalysts was also explored; the results disclosed that the samples could be applied for five cycles without exhibiting a notable change in photocatalytic performance or morphology.

Effect of ionising irradiation on silver release from polyolefin/silver nanocomposite films into food simulants

ABSTRACT Two types of nanocomposite films, polyethylene/silver (PE/Ag) and polypropylene/silver (PP/Ag), were prepared and characterised. Assessment of silver released under the effect of ionising irradiation was performed on the nanocomposite films. The release experiment was carried out by immersing the nanocomposite films in water, 3% acetic acid or 95% ethanol as food simulants and measuring the Ag release from nanocomposite films treated with and without gamma or electron beam irradiation at a dose of 10 kGy. In general, irradiation treatment increased the Ag release regardless of the type of polymer and food simulant. One reason could be radiation-induced metal oxidation at the surface which in turn promoted ion release into food simulants. The oxidising radicals produced by radiation in solution could be another factor speeding up metal oxidation and subsequent ion release. When comparisons were made between the two types of irradiation, greater Ag release into water and 3% acetic acid was observed after electron beam irradiation, while gamma irradiation was likely to induce greater Ag release into 95% ethanol. Such phenomena reveal the influence of different types of radiation on the solutions which in turn affect the Ag release.

Heat Generation in Irradiated Gold Nanoparticle Solutions for Hyperthermia Applications

Gold nanoparticles (GNP) aided hyperthermia has demonstrated promising results in the treatment of cancer. However, most existing investigations focus only on the extinction spectra of GNP solutions, few reported the actual heat generation capability of these solutions to estimate their real potential in in-situ hyperthermia treatment. In this study, the impact of GNP clustering on the optical properties and heating capability of GNP aggregates in acidic solutions have been investigated. It was found that localized heat generation could be significantly enhanced (to up to 60.0 °C) when acidic solutions were illuminated by a near infrared light source at 1.7 W/cm2. In addition, infrared thermography imaging can only detect the surface temperature during thermal treatment, leaving the localized temperature distribution inside the tissues unknown. To overcome this limitation, in this study, the absorbed energy during NIR irradiation in GNP solutions was obtained computationally by coupling the P1 approximation with the DDA calculation to predict the localized temperature change in the solutions. It was demonstrated that due to the accumulation and dissipation of heat, some local areas showed higher temperature increase with the hot spots being connected and merged over time.

Heating Profile of Long Alkyl Chain Ionic Liquid Doped Solvents Under Ultrasound Irradiation

In this work, the heating profile of water, dimethyl sulfoxide (DMSO), acetonitrile (CH3CN) and ethanol (EtOH) and their solutions containing monocationic (CnMIMBr, n = 4, 6, 8, 10, 12, 14 and 16) and dicationic (di-CnMIMBr, n = 4, 6, 8 and 10) imidazolium-based ionic liquids (ILs) were evaluated under ultrasound irradiation. Similarly, ILs (CnMIMBr, n = 4, 8 and 14) with the BF 4 − anion and inorganic salts, such as NaBr and NaCH3CO2 were also evaluated. The results showed that water and DMSO have a linear heating profile; while CH3CN and EtOH have a logarithmic profile. In general, the IL-containing solutions heated up a little faster than the pure solvents, which indicates that the cationic moiety of the ILs did not cause notable changes in the heating profile of the solvents. The IL concentration and the consequent dissociation effects on this were not observed in any of the experimental conditions tested. The addition of NaBr and NaCH3CO2 changed the heating profile of EtOH, resulting in a linear profile. Additionally, our results confirmed that experimental parameters, such as irradiation amplitude and solution volume, significantly change the heating profile of solvents. Finally, under conventional heating and stirring (silent experiments), the heating profile of the pure solvents and the IL-containing solvents indicated that, under ultrasound, the cavitation process makes the heating faster and more efficient. Determination of the dissipated power reflected the solvent’s heating profile more than its heat capacity; therefore, the heating rate in ultrasound reveals the cavitation effects in the particular medium. These results are important because they show that the catalytic effects of ILs in chemical reactions or the solvent effects in micro extraction processes under ultrasound irradiation can be retained without raising the temperature and without decomposition of the ILs or products.

Improved photocatalytic oxidation of arsenic (III) with WO3/TiO2 nanomaterials synthesized by the sol-gel method

Photocatalytic oxidation of arsenite (As(III)) to arsenate (As(V)) was studied in aqueous solution using a series of WO3/TiO2 semiconductors readily synthesized through sol-gel method with WO3 content in the range of 1-5 wt%. The resulting materials showed enhanced photocatalytic activity towards As(III) photo-oxidation compared to their individual counterparts under UV radiation. The amount of As(III) and As(V) species in the irradiated solution was determined using the molybdenum blue method. The efficiency of photoinduced carriers separation was further affirmed by electrical impedance spectroscopy (EIS) and photocurrent tests. The maximum catalytic efficiency was observed when the binary oxide 3%WO3/TiO2 (TW3) was used, reaching a 99% conversion of As(III) to As(V) within the first 25 min under UV irradiation. The enhanced photocatalytic performance of the heterostructures could be explained as consequent to an improved charge separation due to the migration of photoproduced holes in TW3 photocatalyst. Based on the electric band structure of WO3 and TiO2, a reasonable mechanism for the photo-oxidation of As(III) over TW3 novel catalyst has been proposed.

Photocatalytic degradation efficiency of azo dye in aqueous phase using different photo catalysts

The new azo dye [4-(4-hydroxy-2-methylnaphthyl)diazenyl]benzoic acid was synthesized by the reaction of 2-methyl-1-naphthol with p-amino benzoic acid. The photcatalytic degradation of azo dye has been investigated by using zinc oxide and cadmium sulfide. This degradation was carried out by the irradiation of aqueous suspended solutions containing different concentrations of this dye using 0.11 g/100 mL of metal oxide (semiconductors) ZnO and CdS. A mercury lamp 125 W in a Pyrex photoreaction cell of 100 mL at room temperature was used as an irradiation source. The effect of the catalyst on the photocatalytic degradation of the prepared dye was studied via several experiments at different conditions, where they involve the effect of the catalyst mass and the effect of the dye concentrations. The irradiated solutions were studied using UV-Vis spectrophotometer. It has been the performance of photocatalytic system that using ZnO was observed to be better than cadmium sulfide system for degrade the azo compound from its aqueous solution.
 
 KEY WORDS: Photocatalytic, Degradation, Semiconductors, Zinc oxide; Cadmium sulphide, Azo dye
 
 Bull. Chem. Soc. Ethiop. 2020, 34(3), 463-469.
 DOI: https://dx.doi.org/10.4314/bcse.v34i3.3

Field demonstration of irradiated sodium alginate as tea production booster

Sodium alginate oligomers were tested for tea plant growth promoter and anti-fungal agent in this experiment. Sodium alginate solutions were irradiated by Co-60 gamma radiation with different radiation doses to produce the oligomers. Irradiated solutions were then diluted into 150, 300 and 500 ppm prior to foliar application. Solutions were applied through foliar spraying at 7 days interval and the best response of tea plants in terms of various attributes were recorded. Tea buds were collected in 10 days of interval and the growth attributes like- total number of buds, fresh weight of buds, average leaf area and weight per bud, weight of made tea etc. were calculated. The experiment was continued up to 12 weeks and the attributes were averaged to get results per plucking. 12 kGy radiation doses along with 300ppm solution showed the best results and about 36% increase in productivity was found based on the fresh weight of buds. Total fungal count in tea leaves was also found to be reduced greatly. Based on the present study, irradiated sodium alginate could be used as safe and environmentally friendly agent to increase tea production.