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Physics and chemistry of radiation
, pages 27-34
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The radiation-induced degradation of salicylic acid (SA–) in aqueous solutions (1.0 and 0.1 mmoldm−3) saturated with N2Air or no oxygen were tested. Irradiation was done with a cobalt-60 source. With 1mm mold−3solution saturated with N2Complete degradation appeared to occur at about 18 kGy, although at this dose small amounts of 2,3-dihydroxybenzoic acid, catechol and 2,5-dihydroxybenzoic acid were present at concentrations of 67, 22 and 6 μmol/m−3and under air and without oxygen, respectively, the three radiolytic products were present at 18.54 kGy during A.E.–only 90% and 62% were destroyed respectively. In the case of 0.1 mmoldm−3a–solutions, the acid was decomposed by 3.5 kGy if the solution contained N2O, 5.8 kGy in air and 7 kGy without oxygen. The concentration of radiolytic products increased with increasing dose and decreased after a max. After oxidation, chemical oxygen demand was measured. The slopes were 0.48 and 0.11, 0.21 and 0.07, 0.15 and 0.03 mmoldm−3kGy−1for 1.0 and 0.10 mm dies−3N-saturated solutions2The or air or no oxygen.
There are several studies concerning the removal of organic compounds from water using various advanced oxidation processes (AOPs) based on the in situ production of a strong oxidant, such as e.g.•OH, in sufficient concentration to effectively disinfect water (Munter, 2001, Torun et al., 2014, Csay et al., 2014). Such methods include heterogeneous photocatalysis with TiO2Suspensions (Palmisano et al., 2007), photoelectro-Fenton reactions using UVA and sunlight (Flox et al., 2007), ozonolysis (O3+ UV radiation) and peroxonization (Zaviska et al., 2009), Photo-Fenton processes using H2Ö2/Fe2+/UV (Brillas et al., 2009) and ultrasound in the presence of other oxidizing agents (Ma, 2012). Other works have described the oxidation and degradation/destruction of organic pollutants in water using ionizing radiation (Getoff, 1999; Peller and Kamat, 2005; Report of the 2nd RCM, 2012; Homlok et al., 2013; Wojnárovits and Takács, 2005) . . .
Salicylic acid (SA) is widely used as a drug mainly for the treatment of skin diseases (Madan and Levitt, 2014). This acid acts as an antacid, mild antibiotic, bactericide and antiseptic. SA is also used as a food preservative. However, it is ototoxic and causes central nervous system disorders. SA is also used in the manufacture of other drugs such as acetylsalicylic acid (aspirin), 4-aminosalicylic acid, sandulpiride, bismuth hyposalicylate, etc. However, pharmacological residues can have adverse effects on human health. Therefore, it is important to determine the pharmacological impurities in water intended for human consumption. SA is an active metabolite of aspirin after it has been processed by the body. Microbial and chemical degradation of aspirin involves its conversion to SA. Aspirin has been found in wastewater in many countries. For example, in Tokyo, aspirin was the most prevalent drug in water treatment plant influent, with an average concentration of 7300 ngdm−3(Nakada et al., 2006). Various AOPs have been developed for the liquidation of A.E. An example is photoelectrochemical oxidation with TiO2Nanotube matrices (Tian et al., 2009) were found to have first-order kinetics and 83% (30 ppm) decay oxidation over 2 h. Guinea and others. (2008) investigated SA mineralization by various electrochemical methods using boron-doped platinum and diamond as anode. They experienced rapid destruction at the point of totality•OH is produced on a boron-doped diamond anode. Zanta and Martínez-Huitle (2009) and Chen et al. (2010) showed that the Fenton method was more efficient in acidic SA degradation conditions and required only a short time. In Garza-Campos et al. (2016) studied different AOPs and found that the best treatment for SA mineralization was achieved through the coupling of solar photoelectro-Fenton and solar heterogeneous photocatalysis due to additional oxidation by•Oh no TiO2Surface.
The present study evaluates the use of ionizing radiation to degrade SA in water (salicylate-SA).–).
a–, dihydroxybenzoic acid (DHBA), catechol (CAT) and potassium ferricyanide, all of the purest commercially available grade, methanol (HPLC grade) and acetic acid for analysis (99.7%) were all from Sigma-Aldrich. The gases N2O (atomic absorption grade) and He (ultra high purity grade) were supplied by Praxair. For digestion: COD Ultra-Low Range Hach Reagent (0.7-40 mg/dm).−3Ö2) was used. The water used in all irradiation experiments and for the preparation of standard solutions was pooled
Many species are formed mainly during the radiolysis of water (Spinks and Woods, 1990).•ohe H•, who play the main role in the dismantling of A.E–:
Additionally, the water is treated with N prior to radiolysis2O for saturation of the solutions,is quantitatively transformed•OH (K= 9,1 × 109dm3Mol−1small−1) (Buxton et al., 1988) and the income of the directly educated andhas been converted•OH is G(•OH) = 0.56μmolJ−1, according to the following reaction (Janata et
SA-Radiolyse–in aqueous solution
In reaction (5) only the•There is OH (0.56 µmoldm).−3). It is a radical attack on South Africa–into the aromatic ring vacancies by an addition reaction to form the carboxy-dihydroxycyclohexadienyl radical. An oxidant is required for aromatic hydroxylation, and product yields vary significantly depending on the oxidant used. K3Fe(CN)6quantitatively oxidizes the dihydroxycyclohexadienyl radical (Albarrán and Schuler, 2002; Bhatia and Schuler, 1974; Eberhardt, 1974; Madhavan and Schuler, 1980).
The chromatographic method used was simple and allows the separation, determination and quantification of the radiolytic products formed in the irradiated A.E.–solutions, thus making it a powerful tool to indirectly determine the changes that occur in aromatic compounds and to fund these chemiluminescence studies.
Gamma irradiation is an effective method for degrading SA–in aqueous solutions.•OH was the main species responsible for the oxidation reaction that degrades SA–in all solutions
Using γ-radiation from a stable source of cobalt-60 to irradiate water creates several types, such as•OH, which due to its electrophilic character leads to addition reactions preferentially at electron-rich centers of aromatic compounds. 2,3-DHB–is the major product considering the combined effect of the two substituents on SA–Molecule. HE•The OH radical is responsible for a significant portion of the observed degradation, followed by the hydrated reducing agent.
This work was supported byPAPIIT-EINS, (grant no.IN202916). The authors thank Dr. Carol H. Collins for comments. Thanks also to Fish. Francisco García (ICN-UNAM) for conducting the radiation treatments.
- M.What ifand others
Photoelectrochemical oxidation of salicylic acid and salicylaldehyde in titanium dioxide nanotube matrices
- EU.Snyderand others
Hydroxyl radical-induced degradation of salicylates in aerated aqueous solutionSee Also6.1.8: Molecular structure and acid-base behaviorThermal degradation mechanism and thermal degradation rate constants of poly(epichlorohydrin-co-ethylene oxide) derived from GC-MS pyrolysis studies
rays. physical chemistry
- EU.Snyderand others
Radiolysis of paracetamol in dilute aqueous solution
rays. physical chemistry
- G.Palmisanand others
Selectivity of hydroxyl radicals in the partial oxidation of aromatic compounds in heterogeneous photocatalysis
- N.Nakadaand others
Pharmaceutical chemicals and endocrine disruptors in municipal wastewater in Tokyo and their removal in activated sludge treatment
- v.Madhavanand others
A radiation chemical study of the oxidation of the hydroxycyclohexadienyl radical by ferricyanide
rays. physical chemistry
- R.K.Madanand others
Review of the toxicity of topical salicylic acid preparations
Gelatin. academic Dermatol.
- K.Cubicand others
Degradation of catechol by ionizing radiation, ozone, and the combined ozone-electron beam process
rays. physical chemistry
- R.Shelland others
Degradation of organic molecules in advanced oxidation processes: relationship between chemical structure and degradability
- MI.Guineaand others
Metallization of salicylic acid in acidic aqueous media by advanced oxidation electrochemical processes using diamond-doped platinum and boron as anode and generated hydrogen peroxide as cathode
Radiation and environmental chemistry
rays. physical chemistry
Degradation of salicylic acid through advanced oxidation processes. Photoelectronic solar Fenton coupling and heterogeneous solar photocatalysis
J Hazard. Fellow.
Metallization of Mecoprop herbicide by Photoelectro-Fenton with UVA and sunlight
Applications of advanced oxidation processes for the removal of salicylic acid from synthetic wastewater
Chin. chemical substance license
Oxidation of hydroxybenzoic acids by the radiolytically generated OH radical
rays. physical chemistry
Combined effects on the reaction of OH radicals with aromatics. Radiolytic oxidation of salicylic acid
rays. physical chemistry
Micellar Capillary Electrophoretic Chromatographic Analysis of the Products Resulting from the Oxidation by Radiolysis of Toluene and Phenol
rays. physical chemistry
Hydroxyl radical as a probe of charge distribution in aromatics: phenol
J. Phys. Chem. ONE
Radical spectra and product distribution after electrophilic attack of the OH' radical on 4-hydroxybenzoic acid and subsequent oxidation
J. Chem. Soc., Faraday Trans. ΕΕ
HO reactivity2/SHE2Free radicals in aqueous solution
J. Phys. Chem. Dado
The oxidation of hydroxycyclohexadienyl radicals by metal ions
J. Phys. Chem.
Quote from (10)
Radiolysis-induced degradation of 1,3-dichlorobenzene and 4-chlorophenol in aqueous solution
2021, Radiation Physics and Chemistry
Other methods include photocatalysis and TiO2 (Lin et al., 2011), TiO2 and ozone (Lu et al., 2012; Sancey et al., 2014), TiO2 and sonication (Selli et al., 2008), ultrasound (Rayaroth et al. .al., 2008). al., 2014). al., 2017), Fenton, photo-Fenton (Zhang and Pagilla, 2010; Pavas et al., 2017; Andreozzi et al., 2006; Richmond, 2015), electrochemical and electro-Fenton methods (Sirés et al., 2014 ). ; Liu et al., 2011; Nazari et al., 2019; Zazou et al., 2019). These methods also include oxidation by ionizing radiation (Cooper et al., 1993; Trojanowicz et al., 2002; Homlok et al., 2013; Wojnárovits and Takacs 2016; Albarrán and Mendoza 2018, 2020c), and impact e20 has technological advantages since no reagents need to be added. Getoff and Solar (1986) studied the degradation of some chloroaromatic compounds, explained complex degradation mechanisms of this class of compounds, and provided a blueprint for the technical application of a high-energy electron beam.
The degradation of 1,3-dichlorobenzene (1,3-DClB) was studied to obtain yields of radiolytic products (Gin total=0.546μmol/J) and degradation in aerated or oxygen-free aqueous solutions saturated with N2Oh you N2O contains K3Fe(CN)6. In the four environments, several peaks corresponding to byproducts were observed in the chromatograms, with more oxidized products produced in N.2The saturated solutions. The absorbed dose required to remove 1,3-DClB increased with increasing solute concentrations in the aerated solution. Furthermore, the degradation of 4-chlorophenol (4-ClP) at a concentration of 0.3 mmol/dm was investigated3Solution with gamma radiolysis in the presence and absence of oxygen. The results showed that 4-ClP degrades to N faster2environment, verified by the quantification of product concentrations at different doses, the value of chemical oxygen demand and a kinetic study. Hydroquinone, a radiolytic product, is very resistant to degradation. The dose required to completely degrade a gaseous solution of 4-ClP reached 9 kGy. however in N2The saturated solution required only 4.5 kGy for this. The kinetics behave similarly in both compounds and are pseudo-first order. It is important to note that the number of chlorine atoms in the molecule determines the chemical oxygen demand, as this determination was easy for 4-ClP but not for 1,3-DClB.
Abnormalities detected during hydrodynamic cavitation using salicylic acid dosimetry to measure root production
2020, Journal of Chemical Engineering
2,3-DHBA was mainly formed, followed by catechol and 2,5-DHBA. The reason why 2,3-DHBA is the preferred product probably lies in the fact that the -COOH and -OH groups of the SA molecule direct the site of OH attack, and the ortho and para positions in the -OH with higher positions occupy an electron . density and is therefore mainly subject to electrophilic OH attack [24,13]. It is difficult to compare our results in more detail with the available literature (i.e. the concentration of the products formed) as the experiments in the literature were done in deionized water and mainly with AC and not with HC.
Previously, cavitation in hydraulic turbines was fraught with negative consequences, but today it is widely used to purify water, destroy microorganisms and break down organic compounds. In this study, the quantOH is formed during hydrodynamic cavitation using salicylic acid dosimetry. The amount of radicals was determined by quantifying the concentration of 2,3-dihydroxybenzoic acid, catechol and 2,5-dihydroxybenzoic acid. Two concentrations of dosimeter in tap water, 50 and 300 mg L, were tested.−1(pH about 2.5). After 90 min of cavitation using a venturi constriction, the sum of the three products was found to be 0.97 µgml−1e 1.81 μgml−1However, the study revealed abnormalities in cavitation development when a higher concentration of salicylic acid was used - cavitation progressed more evenly, with less pronounced collapses, which had nothing to do with pure water. Detailed observations of cavitation and additional bubble dynamics simulations showed that the surface tension reduction of the acidified salicylic acid solution is the most important physical property. Additional nucleation and coalescence experiments showed that high salicylic acid concentration also leads to prolonged bubble stability and prevents coalescence due to short-range repulsive forces (steric hindrance), resulting in less violent bubble collapse. We also discuss the importance of having a sufficient quantity of dosimeters for its proper evaluationOH production in a specific cavitation device (50 mg L−1currently). This is crucial for future cavitation exploration studies to avoid misinterpretation of the obtained results.(Video) The Science Behind My Favourite Skincare Acids | Lab Muffin Beauty Science
A clay and bleached earth carbon catalyst used for effective ozonation of objectionable substances in water
2020, Total Environmental Science
C and the inorganic components SiO2, Al2O3, MgO, Na2O, Fe2O3, CaO and K2O also promote •OH production. •OH and molecular ozone oxidize benzoic acid through electrophilic (Albarrán and Mendoza, 2018) and nucleophilic (Nawrocki and Fijołek, 2013) additions. Stepwise hydroxylation of benzoic acids and phenol was the dominant pathway (Brillas et al., 1998).
Catalytic ozonation is an effective process that can be used to break down inert organic matter. Carbonaceous clay compound derived from refinery bleaching earth (SBE) is an economical and readily available catalyst that can be used in the ozonation treatment of recalcitrant substances in wastewater. Four SBE-N catalysts2-650, SBE-N2-850, SBE-O2-650 and SBE-O2-850 were made by heating the SBE to 650 and 850 °C under N2or the2Conditions. high surface areaH-posts on SBE-N2-650 and SBE-O2-650 compared to SBE-N2-850 and SBE-O2-850 led to an increase in catalytic activity. Additional carbon (C) present in SBE-N2-650 e SBE-N2-850, had a positive effect on the catalytic activity. The SBE N2-650 showed the highest activity among the prepared catalysts. SBE-N is formed during catalytic ozonation2-650 increased the mineralization rate of benzoic acid by 36% compared to simple ozonation. Molecular ozone was depleted at surface active sites in SBE-N2-650, produces active •OH, •O2−, the1Ö2Kind. Gaseous and liquid products with calorific value generated in SBE-N2Preparation -650 can continue to be used. This study presents a potential use of SBE for the ozonation treatment of refractory wastewater.
Challenges in Using Renewable Energy to Reduce Greenhouse Gases (GHG) and Carbon Footprint
2020, Encyclopedia of Renewable and Sustainable Materials: Τόμοι 1-5
This article briefly discusses the various challenges and aspects of renewable energy and reducing greenhouse gas impacts and carbon footprint. In the current scenario, economic growth has led to an increase in non-renewable energy consumption. Most non-renewable energy sources emit uncontrollable greenhouse gases and thus contribute to a significantly higher carbon footprint. This leads to drastic global warming and pollution. Most developed nations are now united to fight the menace. They thought of some ecological energy resources. Various renewable energy sources for electricity generation are being introduced worldwide. This article briefly examines some of these aspects, considering renewable energy sources such as hydropower, wind power, photovoltaics, fuel cells, biomass, ocean thermal energy and geothermal energy sources as electricity generation for environmental reasons. The main disadvantage of non-renewable energy sources is carbon dioxide (CO) emissions.2) and methane (CH4), which is expressed in carbon footprints, which they use as an indicator of air pollution. To reduce greenhouse gas production, the United Nations Framework Convention on Climate Change (UNFCCC) was established and the Kyoto Protocol was proposed as a result. Energy monitoring and trading are the main features of this protocol. Recently, the concept of carbon sequestration has gained traction. Due to climate change, all developing countries are now under pressure to reduce greenhouse gas (GHG) emissions into the atmosphere. The impact of greenhouse gas emissions on climate change is becoming worse than we thought a decade ago. The most effective way is to start a path of sustainable development and move from environmentally sustainable technologies to renewable technologies.
Enhanced catalytic activity of double perovskite modeled with 3D network structure for the degradation of salicylic acid under microwave irradiation: insight into the catalytic mechanism
2019, Journal of Chemical Engineering
However, the discharge of SA into the aquatic environment through the production process and daily consumption, even at trace concentrations, would have long-term negative effects on human health, such as: B. Ototoxicity and central nervous system disorders . Many studies have shown that SA is regularly detected in urban wastewater and rivers due to its inefficient removal by traditional technologies in wastewater treatment plants [1,2]. Currently, the advanced oxidation process (AOP) with in situ production of reactive oxygen species (ROS) such as hydroxyl radicals (OH) has emerged as an important class of technology to accelerate the oxidation and destruction of a variety of organic pollutants. ,4].
Salicylic acid (SA) is considered a priority pollutant due to its physiological toxicity and pseudo-persistence in the environment. In this study, a novel catalytic degradation technology using microwave (MW) shaped double perovskites was proposed and applied to process SA in aqueous solution. A series from LaCo1-XCuXÖ3@PMMA (X=0, 0.3, 0.5, 0.7, 1) Perovskite catalysts with a 3D porous network structure were synthesized using the polymethyl methacrylate (PMMA) modeling method and characterized by scanning electron microscopy (SEM), N2Adsorption-desorption (BET) analysis, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and microwave lattice analysis. The results showed that the addition of the PMMA template and its replacement with Cu (X=0.5) were beneficial for LaCo production0,5Cu0,5Ö3@PMMA with high catalytic activity, featuring a unique three-dimensional porous network structure, smaller particle size distribution, better microwave absorption performance, and higher Co content.3+/Plus2+andAdvertising/Öhe smiled. The SA removal obeyed the pseudo-first-order model, and the removal efficiency first increased and then decreased with increasing MW intensity, solution pH, and catalyst dosage, and decreased with increasing initial SA concentration. hello co0,5Cu0,5Ö3The @PMMA catalyst showed favorable recycling and stability in repeated experiment. Excellent catalytic activity has been attributed to both active species and MW “hot spots”.Oh andplayed an important role in the catalytic process and the MW "hot spot" effect contributed little to the degradation. So LaCo0,5Cu0,5Ö3@PMMA/MW technology with rapid degradation and negligible secondary pollution offers a potential way to treat salicylic acid in water.
CdS and Ag synergistically increased the yield of g-C
3N 4in the photocatalytic degradation of visible light by pollution
2022, Environmental Science and Pollution Research
Featured Articles (6)
Enhanced photolytic and photooxidative treatments for the removal of selected pharmaceutical components and their degradation products in aqueous matrices
Microchemical Journal, Band 150, 2019, Artikel 104136(Video) Redox Biology 2014 - Introduction, Redox Chemistry
Photolytic and photooxidative degradation of diclofenac (DICL), naproxen (NAPR) and carbamazepine (CARB) was compared with a conventional low-pressure mercury vapor lampEUmaximum= 254 nm and a vacuum UV (VUV) that also emits at 185 nm (at 11%) in 5×10 enriched ultrapure water (UPW) and municipal wastewater (WW).−6M for each drug. Almost complete photolytic and photooxidative degradation by VUV irradiation was observed for all three compounds within 2 min. A reduction of total organic carbon of about 75% was observed in UPW-irradiated samples embedded in 2-5 × 10−5M levels in 15 minutes. Efficient degradation of DICL, NAPR and CARB was achieved in photolysis and photooxidation (PhO) enriched WW at 185 nm (11%) in 1, 2 and 10 min, respectively. Various aromatic degradation products of DICL, NAPR and CARB were identified by quadrupole time-of-flight mass spectrometer coupled to ultra-high-performance liquid chromatography after preconcentration by off-line solid-phase extraction with UPW matrix irradiation with selected drugs at 254 nm For many degradation products, other chemical structures as those previously reported. Furthermore, acridine has not been reported as a photodegradation product for DICL. Downgrade routes have also been suggested. Almost complete degradation of DICL, NAPR, and CARB and their degradation products by VUV+PhO in WW occurred in 5, 10, and 30 min, respectively. However, the total organic content in the WW sample only decreased by 25%.
•OH substitution and addition reactions with p-substituted phenols
Radiation Physics and Chemistry, Volume 133, 2017, pp. 58-66
The directional effect of a hydroxyl group in its substitution and addition reactions•OH for the substituted and free positions on aromatic rings ofPiSubstituted phenols were studied in aqueous solutions containing K3Fe(CN)6as an oxidizing agent of the initially formed substituted hydroxycyclohexadienyl radical or by using ascorbic acid. The results showed that his attack•OH at the substitution position (ipsoThe substituent was then removed to form hydroquinone. The addition reaction of•OH at the free ring position produced 4-substituted catechol and 4-substituted resorcinol derivs. Identification and quantification of the radiolytic products was performed using high performance liquid chromatography. Performance results are given forPi-Halophenol (Pi-X-Ph)Pi-F-Ph,Pi-Cl-Ph,Pi-Br-Ph ePi-I-Ph. other links,Pi- Nitro-Ph,Pi-OH-benzoic acid,Pi-OH-Benzonitrila,Pi-OH-Benzaldehyde,Pi-OH-Anisol ePi-OH-Benzyl alcohol (represented asPi-Z-Ph) were studied only with K3Fe(CN)6as an oxidizing agent. The results show thatPi-X-Ph are attacked by•Oh noipsoPosition for halogen in ratio 1:0.53:0.46:0.11 for F>Cl>Br>I. THE•oh he attackedipsoplace for thePi-Z-Phs by substitution reaction depending on the substituent group. Thus, strong deactivating groups produced less hydroquinone, indicating a lower substitution reaction than strong activating groups.
5-Amino-2-mercaptobenzimidazole off-fluorescence with Ag3O4 nanoparticles: experimental and theoretical investigations
Sensors and Actuators B: Chemical, Band 225, 2016, S. 463-468
The binding interaction of 5-amino-2-mercaptobenzimidazole (AMB) with Ag3Ö4Nanoparticles were studied. AMB strongly adsorbs on nano-semiconductor surfaces. The interaction of AMB with Ag3Ö4was examined by absorption, fluorescence, FT-IR, SEM and EDX spectral studies. the limited liability company3Ö4The nanoparticles were chemically synthesized and characterized by XRD study. The excellent results were due to electron transfer between AMB and Ag3Ö4nanoparticles. To confirm the Ag binding site3Ö4With AMB, the molecular electrostatic potential (MEP) study was carried out theoretically. He confirmed the higher electron density on the nitrogen atom of azomethine. Photoinduced electron transfer is responsible for the quenching of AMB fluorescence. The interaction between AMB and Ag3Ö4occurs through the mechanism of static elimination. The apparent correlation constant (KApplication=2,0×105M−1) was obtained from the fluorescence quenching data.
Co-occurrence of spinal epidural abscess and disc herniation leading to irreversible neurological deficits: case report and literature review
Radiology Case Reports, Band 13, Ausgabe 3, 2018, S. 719-723
Magnetic Zinc Polyindole Oxysulfide ([emailprotected]0.6S0.4@SPID) Coated Core/Shell Nanocatalyst for Simultaneous Photocatalytic H2 Production and BPA Degradation
Environmental Nanotechnology, Monitoring and Management, Band 14, 2020, Artikel 100359
Photocatalyst consisting of zinc oxysulfide core/shell magnetic nanocomposite coated with sulfonated polyindole ([email protected]0,6small0,4/SPID) was prepared and used for H simultaneous photocatalysts2Production and degradation of bisphenol A (BPA). XRD, FE-SEM, EDX, BET surface area, UV-Vis-DRS and VSM were used to characterize the synthesized nanocomposites. The photocatalytic performance was evaluated using a batch reactor under visible light irradiation. Its photocatalytic activity[email protected]0,6small0,4The /SPID nanocomposite has proven to outperform[email protected]0,6small0,4Nanocomposite due to heterosynthesis between SPID and[email protected]0,6small0,4Kind. The results showed that the effect of initial BPA concentration was effective in improving H2Performance with simultaneous photocatalyst H2BPA production and degradation process that allows a maximum increase of 130% of H2Production. ISLAND[email protected]0,6small0,4/SPID nanocomposites showed good stability after five consecutive reaction cycles.
Gamma radiolytic degradation of naphthalene in aqueous solution
Radiation Physics and Chemistry, Band 123, 2016, S. 97-102
The decomposition of naphthalene in aqueous solution was studied using gamma radiation in combination with H2Ö2and TiO2nanoparticles. Gamma irradiation resulted in complete degradation of naphthalene and partial mineralization. At an initial concentration of 5-32 mg/L, more than 98% of naphthalene was removed and the TOC reduction reached 28-31% at an absorbed dose of 3.0 kGy. Naphthalene degradation was faster at neutral pH and the initial degradation rate increased with increasing initial naphthalene concentration. Add H2Ö2and TiO2All nanoparticles increased the degradation and mineralization of naphthalene. The TOC removal efficiency increased from 28% (irradiation only) to 35% with the addition of H2Ö2(40 mg/L) and for 48% with TiO addition2(0.8 g/L). Degradation of naphthalene in aqueous solution by gamma irradiation was mainly due to oxidation by·Roots OH. Naphthol intermediates and carboxylic acids such as formic acid and oxalic acid were identified by LC-MS and IC.(Video) Copper(I) Thiocyanate (CuSCN) Hole-Transport Layers Processed from Aqueous Precursor Solutions
© 2018 Elsevier Ltd. All rights reserved.
What is the degradation of salicylic acid? ›
The degradation products of Salicylic acid are 2,3-dihydroxybenzoic acid, catechol and 2,5-dihydroxybenzoic acid. Degradation mainly takes place in reaction of OH of Salicylic acid in aqueous solution. The COD decreased significantly with dose.Does salicylic acid oxidize? ›
The rate of oxidation of salicylic acid was 16-fold higher than benzoic acid, whereas the rate of oxidation of ASA was four-fold higher.What is the alkylation of salicylic acid? ›
Alkylated salicylic acids are conventionally prepared by the alkylation of a phenol to form an alkylphenol followed by carboxylation of the alkylphenol by the Kolbe-Schmitt reaction to provide the alkylated salicyclic acid.Does salicylic acid degrade over time? ›
Common ingredients like salicylic acid and benzoyl peroxide break down rather quickly once exposed to air and may cause more irritation to the skin. When treating acne, consistency is key and when morning and evening rituals are practiced, the product should not last more than six months.What happens when salicylic acid is dissolved in water? ›
Re: Dissolving salicylic acid
Since salicylic acid is not soluble enough in water at room temperature to achieve your desired composition, it must be converted to salicylate. This can be done by reaction of sodium bicarbonate (baking soda) with salicylic acid in water - the salicylic acid will dissolve as it reacts.
The ferric chloride test was used to compare the salicylic acid, crude aspirin, and purified aspirin. After the addition of the ferric chloride, the salicylic acid solution turned purple, and both the aspirin solutions were yellow.What happens when salicylic acid with sun? ›
No, salicylic acid does not increase the skin's sensitivity to the sun. It can be applied in the morning, even if you plan to go out during the day. Just be sure to use a sunscreen every day that matches your skin tone. Interestingly, salicylic acid may have a photo-protective effect on the skin!What is the redox potential of salicylic acid? ›
Salicylic acid gave the signal at potential of 1.09, which increased with increasing concentration and scan rate.What does salicylic acid clash with? ›
AHAs and BHAs, such as glycolic, salicylic, and lactic acids should never be used with Vitamin C. Vitamin C is an acid, too, and is unstable, so the pH balance will be thrown off by layering these ingredients together and might as well be useless.Why is salicylic acid not soluble in water? ›
Answer and Explanation: Salicylic acid is not soluble in water because it is not polar, the way water molecules are. For one substance to be soluble in another, remember the rule, "like dissolves like".
What does acetylation of salicylic acid produce? ›
Here, salicylic acid is subjected to acetylation with the help of acetic anhydride to yield acetylsalicylic acid (commonly known as aspirin) and acetic acid as the final product.How do you reverse salicylic acid damage? ›
- Say "aloe" to your new best friend! ...
- Invest in a hyaluronic acid serum. ...
- Prioritise rebuilding your skin barrier. ...
- Gently ease back into exfoliating.
Salicylic acid for skin treatment can be used as a daily or weekly exfoliator. Similar to a toner, apply salicylic acid onto freshly washed skin and let it absorb for up to 30 seconds before washing it off.How long does it take for salicylic acid to dry? ›
If you are using a liquid/gel, apply a few drops or a thin coat of the medication to cover the entire wart, callus, or corn using the applicator if provided. Be careful to apply it only to the affected area and not the surrounding skin. Let dry for 5 minutes.Does salicylic acid ionize in water? ›
(a) Both functional groups of salicylic acid ionize in water, with Ka = 1.0 × 10−3 for the—CO2H group and 4.2 × 10−13 for the −OH group.Can you dissolve salicylic acid in water? ›
The solubility of salicylic acid is, according to Moncorps,3 as follows: One part of salicylic acid dissolves in 13 parts of boiling water, in 444 parts of water at a temperature of 15 C., in 500 parts of water at 20 C., in 60 parts of glycerin, in 45 parts of olive oil and in 7 parts of castor oil.Can salicylic acid be neutralized with water? ›
Studies have shown that water is sufficient for neutralizing glycolic acid peels up to 35%. Salicylic 20-35% – Salicylic acid peels will self-neutralize within 3 minutes.Why does salicylic acid become white? ›
Yes, this is normal.
Salicylic acid (the active ingredient in Compound W) is a keratolytic agent and works by peeling off the outer layers of the skin. This can look unsightly and by all means cover it but it is not entirely necessary.
The pH of the salicylic acid aqueous solution was 2.4. Salicylic acid with ferric chloride in water produces a special purple color. salicylic acid is widely used, eczema, psoriasis, acne, dandruff may be used salicylic acid.Why does salicylic acid turn purple? ›
If any salicylic acid remains unreacted, its presence can be detected with a 1% iron(III) chloride solution. Salicylic acid has a phenol group in the molecule. The iron(III) chloride gives a violet color with any molecule possessing a phenol group.
What is the UV absorption of salicylic acid? ›
The UV absorbance of aspirin was determined at 254 nm, and the fluorescence of salicylic acid was measured at 425 nm.Does salicylic acid absorb UV light? ›
Salicylic acid (SA) as a multifunctional interface material is employed to modify the interface of mesoporous cerium oxide (m-CeOx) and perovskite to passivate defect and absorb the UV light, thus fabricating efficient and stable perovskite solar cells.Is salicylic acid UV sensitive? ›
When using products formulated with salicylic acid, it's important that you take the appropriate sun protection measures because salicylic acid is a beta hydroxy acid, which can make your skin more sensitive to the sun, per the FDA.Is salicylic acid a fluorescence? ›
The fluorescence intensity of salicylic acid is weak. The fluorescence was increased by five-fold when sodium dodecyl sulfate was added to the system and the emission wavelength obtained was at 408 nm [Fig. 2(c)] with excitation at 305 nm [Fig. 1(c)].What type of reaction does salicylic acid undergo in this transformation? ›
This is an esterification reaction. The hydroxyl group from salicylic acid and the hydrogen from acetic acid is eliminated as water giving an ester as the product.What is the effect of salicylic acid 2%? ›
Salicylic acid belongs to a class of drugs known as salicylates. When applied to the skin, salicylic acid may work by helping the skin to shed dead cells from the top layer and by decreasing redness and swelling (inflammation). This decreases the number of pimples that form and speeds healing.What chemicals should not be mixed with salicylic acid? ›
Retinoids or retinol and salicylic acid
Generally, it's recommended you don't mix retinol and salicylic acid in your skincare routine due to the risk of redness or potentially irritating side effects.
The short answer is, yes — you can combine these two hero ingredients. In fact, these two ingredients can enhance each other and help your skin look brighter and clearer.Why can't you use salicylic acid? ›
Sunburns: Salicylic acid overuse can cause chemical burns, and regular use can also leave skin overly exposed in the sun. Sunburn is a common side effect for people who use any BHA-containing product, so be sure to use sunscreen along with any salicylic acid product.What is the best solvent for salicylic acid? ›
Salicylic acid is notoriously difficult to dissolve. The best way of dissolving salicylic acid powder is with a mixture of alcohol, water, and propylene glycol. If you are finding this difficult to find, it is thought that vegetable oil makes a good substitute for propylene glycol.
At what temperature does salicylic acid dissolve? ›
The boiling point and melting point of salicylic acid are 211^oC and 315^oC respectively. The salicylic acid molecule has two hydrogen bond donors and three hydrogen bond acceptors. The flashpoint of salicylic acid is 157^oC. Due to its lipophilic nature, its solubility in water is very poor i.e., 1.8 g/L at 25^oC.What is the chemical reaction of salicylic acid and water? ›
Acetyl salicylic acid (aspirin) ionises in water as: HC9H7O4+H2O→H3O++C9H7O4−; (Ka=2.What happens when salicylic acid is treated with acetyl chloride? ›
Acetyl chloride reacts with salicylic acid in the presence of pyridine to form aspirin. Aspirin is also known as acetylsalicylic acid.Where does salicylic acid occur naturally? ›
Salicylic acid (2-hydroxybenzoic acid) is a white solid first isolated from the bark of willow trees (Salix spp.), from which it gets its name. It also occurs as the free acid or its esters in many plant species.What is the natural source of salicylic acid? ›
Salicylic acid is a beta hydroxy acid (BHA), a type of carbon-based organic compound that naturally occurs in willow bark, fruits, and vegetables, according to Caren Campbell, MD, a San Francisco-based dermatologist.Does salicylic acid degrade in the sun? ›
Stability: Salicylic acid gradually discolours in sunlight; when heated to decompose it emits acrid smoke and irritating fumes. Salicylic acid is used in cosmetic products as a denaturant, a hair and skin conditioning agent, an exfoliant, an anti-acne cleansing agent, an anti-dandruff agent and a product preservative.What is the degradation of aspirin? ›
In aqueous solution, aspirin is known to undergo decomposition by hydrolysis into salicylic acid, and it is reported that the decomposition reaction is promoted at high temperatures, in alkaline solutions, and in the presence of magnesium.What is the degradation product of acetylsalicylic acid? ›
The stability of acetylsalicylic acid in such solutions was tested at room temperature, in a 12h period. In the work, in all cases, only one main degradation product, salicylic acid, was found.What was the main problem with salicylic acid? ›
Salicylic acid topical can cause a rare but serious allergic reaction or severe skin irritation. These reactions may occur just a few minutes after you apply the medicine, or within a day or longer afterward.What happens if you go in the sun after using salicylic acid? ›
A study done by the NCBI found that salicylic acid did not increase sunburn risk the way glycolic acid did. However, we recommend applying sunscreen after using products formulated with salicylic acid as a cautionary measure.
Does aspirin degrade in water? ›
In an aqueous solution, aspirin is known to undergo decomposition by hydrolysis into salicylic acid, and the decomposition reaction is promoted at high temperatures, in alkaline solutions, and in the presence of magnesium.How fast does aspirin degrade? ›
“Most drugs degrade very slowly,” he said. “In all likelihood, you can take a product you have at home and keep it for many years, especially if it's in the refrigerator.” Consider aspirin. Bayer AG puts two-year or three-year dates on aspirin and says that it should be discarded after that.What happens when aspirin reacts with water? ›
Aspirin (acetylsalicylic acid) reacts with water (such as water in body fluids) to give salicylic acid and acetic acid, as shown in Figure 5.2. 2.What two chemicals do old aspirin tablets degrade into? ›
Aspirin reacts slowly with water to give salicylic acid and acetic acid. The green line shows the ester bond that is broken during the hydrolysis reaction. So, when you open an old bottle of aspirin it is common to smell vinegar. This means that at least some of the aspirin has degraded.How does pH affect the degradation of aspirin? ›
In this experience it is observed that the acetylsalicylic acid hydrolysis reaction is faster at acid pH and at 60 ° C. Since Edwards has shown that the rate of hydrolysis of aspirin is independent of pH between pH 4 and 8, the reaction has been the subject of a number of studies, particularly by Garrett [1,3-5].What are the dangers of salicylic acid chemistry? ›
The substance can be absorbed into the body by inhalation and by ingestion. The substance is irritating to the eyes, skin and respiratory tract. The substance may cause effects on the central nervous system and acid-base balance in the body. This may result in delirium and tremors.What are 3 toxic effects of salicylic acid? ›
Nausea, vomiting, diaphoresis, and tinnitus are the earliest signs and symptoms of salicylate toxicity. Other early symptoms and signs are vertigo, hyperventilation, tachycardia, and hyperactivity. As toxicity progresses, agitation, delirium, hallucinations, convulsions, lethargy, and stupor may occur.Is salicylic acid a harmful chemical? ›
While the use of household salicylic acid products at low concentrations is generally considered safe, in high concentrations, salicylic acid is capable of causing moderate chemical burns. If ingested, this chemical can also lead to dangerous intoxication.