Oxalic Research Articles

Screening Organic Acid Contents of Tomato Landraces Collected From Aegean-Mediterranean Region of Anatolia

Tomato landraces can serve as valuable sources for breeding new cultivars aimed at enhancing fruit quality in terms of organic acids. Nineteen tomato landraces spread along the Mediterranean coasts of Anatolia were evaluated to determine their basic internal quality parameters and organic acid composition. The parameters assessed included fruit weight, diameter, length, pH, titrable acidity (TA %), soluble solid content (SSC%), SSC/TA ratio, and organic acids, such as oxalic (OA), tartaric (TarA), malic (MA), malonic (MalA), lactic (LA), acetic (AA), citric (CA), and ascorbic acids (AscA). Significant diversity was observed among the different landraces concerning these traits. Citric acid was found to be the most abundant organic acid within the landraces. Notably, the highest and lowest values for CA were recorded in Ege 8 (105.73 mg g-1) and TR62707 (31.10 mg g-1), respectively, making them promising sources for future breeding programs. Ascorbic acid (AscA) exhibited the lowest content among all the organic acids, ranging from 0.06 to 0.12 mg.g-1 (equivalent to 64-116 µg.g-1). Moreover, the landrace TR49646 displayed the highest malic acid content (8.23 mg g-1), making it a potential source for obtaining high malic acid content. Conversely, Ege 6 showed the lowest malic acid content (5.11 mg g-1). For health purposes, the landrace TR63233 was identified as having the lowest oxalic acid content. Multidimensional scale analysis further confirmed the potential candidates identified by the ANOVA and one-way ANOM tests. The results revealed a considerable diversity among the evaluated landraces, and the identified traits could be instrumental in selecting and breeding new cultivars with improved characteristics.

Enhancing Phytoextraction Potential of Brassica napus for Contaminated Dredged Sediment Using Nitrogen Fertilizers and Organic Acids.

Dredged sediment contaminated with heavy metals can be remediated through phytoremediation. The main challenge in phytoremediation is the limited availability of heavy metals for plant uptake, particularly in multi-contaminated soil or sediment. This study aimed to assess the effect of the nitrogen fertilizers (ammonium nitrate (AN), ammonium sulfate (AS), and urea (UR)), organic acids (oxalic (OA) and malic (MA) acids), and their combined addition to sediment on enhancing the bioavailability and phytoremediation efficiency of heavy metals. The sediment dredged from Begej Canal (Serbia) had high levels of Cr, Cd, Cu, and Pb and was used in pot experiments to cultivate energy crop rapeseed (Brassica napus), which is known for its tolerance to heavy metals. The highest accumulation and translocation of Cu, Cd, and Pb were observed in the treatment with AN at a dose of 150 mg N/kg (AN150), in which shoot biomass was also the highest. The application of OA and MA increased heavy metal uptake but resulted in the lowest biomass production. A combination of MA with N fertilizers showed high uptake and accumulation of Cr and Cu.

Effect of active layer-by-layer edible coating on quality, biochemicals, and the antioxidant system in ready-to-eat ‘Williams’ pear fruit during cold storage

This study tested an active edible coating on the quality and storage capacity of fresh-cut pear stored at 2 ± 0.5 °C for 10 days by incorporating oxalic (OA) and citric acid (CA) into carboxymethyl cellulose (CMC) and sodium alginate (SA). The physicochemical parameters, secondary metabolite and amino acid contents, and antioxidant activities were determined. Furthermore, enzymes related to oxidative stress and browning, and relative markers were also analysed. The results showed that ready-to-eat pear coated with CMC+SA+OA+CA had a significant inhibitory effect on physiological decay, minimizing the TSS and pH increase and TA decrease. In addition, coating application improved the production of secondary metabolites. The activity of all enzymes involved in ROS detoxification was shown to be promoted by the application of the coating. The degree of browning and oxidative damage that increase progressively with increasing storage time in physiological condition, resulting inhibited by coating. Furthermore, this treatment significantly reduced the protein degradation. Therefore, using the CMC+SA+OA+CA edible coating has the potential to hinder decay and greatly extend the storage period of 'Williams' pear fruit in cold storage.

Cane Pretreatment by Deep Eutectic Solvents to Increase its Reactivity During Enzymatic Hydrolysis with Cellulases

Cane was pretreated with a number of deep eutectic solvents (DESs) based on choline chloride (ChCl) as a hydrogen bond acceptor. Among hydrogen bond donors, lactic (LA) and oxalic (OA) acids were the most effective. Substrate pretreatment conditions (ratio of DES-components, temperature and exposure time) were optimized, which resulted in the highest yield of reducing sugars (RS) and glucose during subsequent enzymatic hydrolysis with cellulase preparation based on Penicillium verruculosum. It was established that in the case of a mixture of ChCl with LA (the molar ratio of components was 1 : 5) pretreatment should be carried out at 80°C for 24 hours, and in the case of a mixture of ChCl with OA (1 : 1), optimal conditions were 80°C and 6 hours. The degree of conversion of the pretreated substrate after 48 hours of hydrolysis in the presence of the enzyme preparation (EP) B537 was 80 and 86% by absolutely dry substances for selected mixtures of ChCl/LA and ChCl/OA, respectively.

Sol‐gel route synthesis of high energy density Li [Li0.2Ni0.3Mn0.7] O2 cathode with controlled structure, morphology and enhanced electrochemical performance

AbstractThe desire for long driving range and low cost of electric vehicles necessitates the use of superior rechargeable lithium batteries. These batteries with enhanced energy density addresses the demand for cutting‐edge cathode materials which can deliver amplified voltage and capacity. Lithium‐rich manganese is one among such promising cathodes for lithium‐ion batteries. In this work, three different organic acids, including oxalic (OX), tartaric (TA) and ascorbic (AS) acids were used to synthesis Li [Li0.2Ni0.3Mn0.7] O2 (LNMO) materials with three unique microstructures. Physicochemical and electrochemical characterization techniques were used to investigate a range of properties. Electrochemical investigations demonstrated regulated morphology‐enhanced electronic conductivity, increased energy density and prolonged cycle behavior. Among the three samples, AS‐LNMO unveiled a capacity of 308.02 mhAg−1 nearing the value of theoretical capacity. Whereas, TA‐LNMO exhibited a remarkable stability even after 200 cycles with capacity retention of 99.3%. With specific discharge capacities of 308.02, 278, 252, 228 and 212 mAhg−1 at 0.1C, 0.2C, 0.5C, 1C and 2C respectively, AS‐LNMO exhibited superior rate capability. Collectively, this research offers valuable insights in using complexing agents which positively impacts the morphology and electrochemical performance of LNMOs in upcoming lithium‐ion batteries.

Impact of Low Molecular Weight Organic Acids on Soil Phosphorus Release and Availability to Wheat

ABSTRACT Phosphorus (P) use efficiency (FPUE) is very low due to fixation of P with the hydrous oxides of iron and aluminum in acid soils and calcium in neutral to calcareous soil. The roots of wheat (Triticum aestivum) excrete low molecular weight organic acids (LMWOAs) to increase P bioavailability in P-deficient soil through acidification, chelation, and exchange mechanisms. However, the amount of LMWOAs excreted in the rhizosphere is small, and they undergo rapid microbial degradation. The present study was undertaken by applying different levels of LMWOAs and phosphorus to the soil followed by sowing of wheat seeds to learn the impact of applying LMWOAs, especially oxalic (OA) and citric acid (CA), on the yield and FPUE of wheat. The results showed that application of P fertilizer along with OA and CA significantly increased the Olsen P concentration in soil and in turn increased P uptake, FPUE, and yields of wheat. Application of OA @ 15 mg kg−1 recorded 20% (±0.22%) and 30% (±0.55%) higher grain and straw yield, respectively, over control and was more effective than CA. Among LMWOAs, application of OA @ 15 mg kg−1 was more effective than CA. Therefore, the application of OA has the potential to reduce the excess application of phosphorus and its buildup in soils and cause eutrophication of water bodies.

Comparative analysis of absorption capacity of Cr(VI) polyaniline and cellulose/polyaniline composites synthesized in aqueous solutions of organic acids

Samples of polyaniline (PAn) doped by different organic acids, namely PAn-FA, PAn-AA, PAn-OA, and PAn-CA, were synthesized by oxidation of aniline (An) with ammonium peroxydisulfate in the 0.5 M aqueous solutions of formic (FA), acetic (AC), oxalic (OA), and citric acids (CA) respectively. Samples of composites of cellulose (Cel) with doped polyaniline (Cel/PAn-FA, Cel/PAn-AA, Cel/PAn-OA, and Cel/PAn-CA)were produced by the same method under the presence of a suspension of microfibrillar bleached cellulose in the reaction mixture. The mass ratio of An : Cel was 1 : 1. The structure of obtained samples was studied using X-ray diffraction, FTIR spectral analysis, and scanning electron microscopy. Adsorption capacity as concerns Cr(VI) by produced samples of both individual polyanilines and composites and adsorption kinetics has been studied by electronic (UV) and fluorescence X-ray spectroscopy and also X-ray energy dispersion analysis methods. Practically full removal of Cr(VI) ions (98–100 %) of such investigated samples of PAns and its composites has been determined. The adsorption kinetics is well described by equations of pseudo first and second orders. According to the results, the Langmuir and Freundlich adsorption isotherms are plotted. It was found that the process of adsorption Cr(VI) ions by doped samples of PAn and Cel/PAn accords to adsorption model of Langmuir. It has been shown, that adsorbed chromium remains in the samples of adsorbents in the form of chromium (III). Keywords : polyaniline, cellulose, composites, structure, Cr(VI), adsorption.

Modeling the photocatalytic oxidation of carboxylic acids on aqueous TiO2 suspensions and on immobilized TiO2-chitosan thin films in different reactor geometries irradiated by UVA or UVC light sources

Photocatalytic reactor models incorporating radiation transport parameters and intrinsic kinetic parameters of photocatalytic decomposition of single-compound and mixtures of oxalic (OA) and formic acid (FA), in both slurry suspensions and immobilized photocatalytic thin films, were validated in two well-mixed annular photoreactors geometries irradiated with either UVA or UVC radiation. The six-flux absorption scattering model (SFM) predicted the radiation field in a titanium dioxide (TiO2 P25) catalyst suspension, the local volumetric rate of photon absorption (LVRPA) at each point of the reactor and, after volumetric integration, the lumped VRPA. The model combining the lumped VRPA, the kinetics models describing the adsorption and photocatalytic decomposition of OA and FA and the material balance of the reacting species was fitted to the experimental results of photocatalytic decomposition of OA and FO in a slurry TiO2 suspension, to determine the OA and FA intrinsic reaction kinetics parameters. Such intrinsic parameters were then used with the average surface rate of photon absorption (SRPA) to model and predict the photocatalytic oxidation of OA and FA on non-porous TiO2–chitosan films immobilized on glass plates immersed in the photoreactor. The models for both slurry suspensions and immobilized photocatalysts predicted the degradation and mineralization of OA and FA and of a mixture of them under diverse experimental conditions. This study demonstrates a systematic methodology for determining intrinsic reaction kinetics rate parameters of water contaminants that can also be used to represent the photocatalytic oxidation of such contaminants in irradiated slurries and in immobilized photocatalytic thin films and in any photoreactor geometry.

Effect of the bleaching and varnishing process on the flame source combustion light intensity of wood material

Bu calisma, ahsap malzemede renk acma ve vernikleme isleminin alev kaynakli yanmada isik yogunluguna etkilerini belirlemek amaciyla yapilmistir. Bu maksatla, Dogu kayini (Fagus orientalis Lipsky), saricam (Pinus sylvestris Lipsky) ve Sapsiz mese (Querqus petraea Liebl.) odunlarindan ASTM D 358 esaslarina uyularak hazirlanan orneklere sodyum hidroksit (NaOH), hidrojen peroksit (H2O2), kalsiyum hidroksit (Ca(OH)2), sodyum silikat (NaSiO3), asetik asit (CH3COOH), sodyum disulfit (Na2S2O5), oksalik asit (C2H2O4) ve potasyum permanganat (KMnO4)’in % 18’lik cozeltisi ile renk acma islemi yapildiktan sonra, ASTM D3023 esaslarina gore su bazli (Sb), sentetik (Sn), poliuretan (Pu) ve akrilik (Av) vernikler uygulanmis ve isik yogunlugu ASTM E 160–50 esaslarina gore belirlenmistir. Sonuc olarak, isik yogunlugu; ahsap turu, renk acma cozeltisi ve vernik cesidi etkilesimine gore en fazla KMnO4+Na2S2O5+H2O2 (R5) ile rengi acilmis sentetik vernikli kayinda gorulurken, en az Na2S2O5+C2H2O4 (R4) ile rengi acilmis akrilik vernikli saricamda elde edilmistir. Buna gore isik yogunlugu en az olan ornekler, yanginda dumandan bogulma riskini arttirabileceklerinden uygulama alanlarinda bu durumun dikkate alinmasi onerilebilir.

UV-visible Spectroscopy as a New Tool to Predict the Bioactivity of Humic Fragments Induced by Citric/ Oxalic Acids on Eucalyptus Nutrition and Growth

ABSTRACT Citric (CA) and oxalic (OA) acids are able to change the humic acid (HA) supramolecular structure, affecting HA effects on plants. This study aimed to evaluate the effect of CA and OA on HA supramolecular structure changes, and how these changes influence the eucalyptus growth and nutrition. HA was combined or not with CA and OA, as follows: HA+CA+OA; HA+CA; HA+OA; HA; CA+OA; CA, OA and control (no HA, CA, and OA). Seedlings were grown in a nutrient solution for 45 days. It was determined the dry matter production, the nutrients contained in the nutrient solution, and their accumulation by eucalyptus. Changes in the HA supramolecular structure were evaluated through the UV-visible light absorbance ratios. Use of HA+OA increased the E4/E6 and A254/A204 ratio, and reduced the E2/E3 ratio over the exclusive use of HA, increasing the reactivity and reducing the aromaticity over intact HA. HA fragmented by OA increased the dry matter production and nutrients accumulated by eucalyptus. CA was not effective in changing the HA supramolecular structure, as well as in improving eucalyptus growth. The HA bioactivity on eucalyptus growth induced by CA and/or OA can be inferred from a new index relates to A254/A204 and E4/E6 absorbance ratio.

Synthesis and physicochemical properties of the mixtures based on choline acetate or choline chloride

In this work the physicochemical properties of newly obtained mixtures (ChM) based on choline acetate (ChAc)/chloride (ChCl) as a hydrogen bond acceptor (HBA) and carboxylic acids (oxalic (OxA), malonic (MA), citric (CA), acetic (AA), formic (FA))/ urea (U) as a hydrogen bond donors (HBD) are discussed. NMR study showed slow reaction between choline and carboxylic acid, leading to obtain ester and water. After 3 weeks of synthesis, water content (wH2O) increased ca. 1.4 and 1.9 times for ChAc+FA and ChAc+OxA respectively. This factor is acid strength (as HBD) dependents. Moreover, the results clearly shown that wH2O can be rapidly determined based on the measurements of the refractive index. The densities of the examined systems are in the range 1.084–1.296 g·cm−3 at 298.15 K, while kinematic viscosity at the same temperature varies from ca. 19 cSt to 2190 cSt for ChAc+FA and ChAc+CA respectively. The highest conductivity was measured in ChCl+FA system and equaled 14.60 mS·cm−1.

ASSESSMENT OF DURABILITY AND CHARACTERISTICS OF CHANGES IN KEFIR MADE FROM COW'S AND GOAT'S MILK

Present study was aimed to determine the changes and the best consumption time of kefir samples made from cow and goat milk using starter culture during the storage at the refrigerator (+4°C for 35 days). It was found that goat kefir (GK) samples had higher pH and lipolysis values during storage while cow kefir (CK) samples had higher values of viscosity. The counts of lactococci, lactobacilli, leuconostoc, total mesophilic aerobic bacteria, acetic acid bacteria and yeast decreased during the storage. Amounts of lactic, acetic, citric, pyruvic and oxalic acids were higher in GK samples. Acetaldehyde, diacetyl and acetoin contents were higher in CK samples. The highest sensory scores were obtained for CK samples on 14th day and for GC sample on 21th day of the storage.

Toxicity of oxalic acid on in vitro reared honeybee larvae

Varroa destructor is considered as a serious pest of honeybees (Apis mellifera) and its resistance to acaricides has been reported since the early 1990s. Because large colony loses are yearly reported from over the world, new methods of treatment for Varroa mites are still in focus of many scientists. In our bioassay, we determined the lethal concentration 72 h LC50 of 2.425% oxalic acid solution following single spray exposure of honeybee larvae under laboratory conditions (Guideline OECD 237, 2013).

Study on the effect and mechanism of total flavonoids from Mosla for rats with calcium oxalate stone in kidney

Objective To explore the effect and mechanism of total flavonoids on calcium oxalate stones in SD male rats, and to provide ideas for the prevention and treatment of calcium oxalate stones. Methods The model of 1% ammonium chloride+ 1% ethylene glycol was used.The patients were treated with placebo, low dose of total flavones and high dose of total flavones.The content and concentration of oxalic acid in rats' 24-hour urine were measured.The contents of calcium and magnesium in urine were determined, and the levels of blood urea, creatinine and serum calcium were determined, HE staining was performed on the kidney sections of rats, and the pathological changes and calcium oxalate crystals were observed and graded under 100-fold microscope. Results The contents of calcium ions in renal tissues, 24-hour urinary calcium ions, calcium oxalate crystals in renal tissues and renal tubular dilatation in rats treated with different doses of flavonoids from comfrey's flower were significantly lower than those in the model group (P<0.05). Conclusions The total flavonoids could prevent the formation of calcium oxalate in kidney of SD male rats. Key words: Urinary Calculi; Calcium Oxalate; Medicago sativa; FLAVONE

Separation of Zirconium and Hafnium by Extraction with 2-octanol.

Zirconium and hafnium are shown to be separable using 2-octanol (C8H18O) as an extractant. Zirconium basic carbonate was dissolved using hydrochloric acids at concentrations ranging from 5 % to 20 %. Potassium fluoride was found to be crucial to the process. Its effect was investigated in the concentration range of 1 M to 3 M. The optimum conditions obtained for extraction were 10 wt % HCl in a 1.5 M KF solution, a contact time of 15 minutes, and 100 % 2-octanol. Under these conditions, the separation factor of zirconium and hafnium is 9.2 with a maximum extraction percentage of 96.58 % of zirconium. The optimum conditions for stripping of zirconium were found to be 3 M H2SO4 as stripping agent, an A/O ratio of 1:1 and 40 minutes contact time. The McCabe-Thiele diagrams constructed from the experimental data indicate that four and five equilibrium stages are sufficient for the extraction and stripping of zirconium respectively. A recovery of 97.25 % of hafnium was obtained using a mixture of oxalic acid and nitric acid as a stripping agent. A study of chemical speciation in the two phases would be important for the improvement of the process.

Modified Zeolite in Methanol to Hydrocarbons Transformation

The work is devoted to the modification of H-ZSM-5 samples with sodium hydroxide and oxalic acid to provide the formation of the mesoporous structure of the zeolite and to obtain optimal Si/Al ratio. Moreover, zeolite active sites were modified with Co, Ni, Fe in order to decrease polyaromatic substances formation during methanol transformation into hydrocarbons. The testing of the samples was performed at 350 oC in a flow reactor, the methanol feed rate was maintained at 0.16 g(methanol)/(g(Cat)*h). Dimethyl ether transformation rate into hydrocarbons was found to be 0.055-0.1 kg(DME)/(kg(Cat)*h) for investigated catalysts. Alkali treatment of H-ZSM-5 samples results in the formation of a mesoporous structure with a mean pore diameter of 5 nm. Formation of additional mesopores results in some increase of dimethyl ether to hydrocarbons transformation rate up to 0.09 kg(DME)/(kg(Cat)*h). Zeolite treatment with oxalic acid results in decreasing of Si/Al ratio from 0.76 to 0.41 that case some decrease of dimethyl ether transformation rate from 0.07 kg(DME)/(kg(Cat)*h) to 0.05 kg(DME)/(kg(Cat)*h), however considerable decrease of polyaromatic hydrocarbons concentration in reaction media was achieved for sample with lowest Si/Al ratio. Modification of H-ZSM-5 with Co, Fe, Ni results in some increase of dimethyl ether transformation rate up to 0.07-0.1 kg(DME)/(kg(Cat)*h) and a considerable decrease of polyaromatic hydrocarbons concentration in reaction media due to active sites modification.The ZSM-5-Ni-0.001M sample showed highest activity 0.1 kg(DME)/(kg(Cat)*h).

Kinetics and Mechanism of Oxidation of Oxalic Acid With Bi(V) in HClO 4 - HF Mixture

Kinetics and Mechanism of Oxidation of Oxalic Acid With Bi(V) in HClO 4 - HF Mixture

Effect of Organic Acids on Molecular Mobility, Physical Stability, and Dissolution of Ternary Ketoconazole Spray-Dried Dispersions.

In an earlier investigation, ketoconazole (KTZ)-organic acid coamorphous systems were prepared, wherein, in the solid-state, there was ionic and/or hydrogen bonding interactions between the drug and the acid( Fung , M. ; Berziņš , K. ; Suryanarayanan , R. Mol. Pharmaceutics , 2018 , 15 ( 5 ), 1862 -1869 ). While the coamorphous systems accelerated KTZ dissolution, the organic acids were not effective in maintaining supersaturation, and drug precipitation was observed. Ternary drug-polymer-acid amorphous solid dispersions (ASDs) were prepared with KTZ, polyvinylpyrrolidone (PVP), and each oxalic (OXA), tartaric (TAR), citric (CIT), or succinic (SUC) acid. When compared with amorphous KTZ, solid dispersions of KTZ-PVP exhibited a moderate reduction in molecular mobility and small improvement in dissolution performance. The incorporation of acid (OXA, TAR, or CIT) in PVP-KTZ solid dispersion led to orders of magnitude increase in α-relaxation times and decrease in the crystallization propensity. These ternary ASDs were stable while crystallization of the cocrystal was observed in the SUC system. Moreover, the addition of acids also dramatically improved the dissolution performance of KTZ, a result attributed to KTZ-acid interactions.

Lithagogue effects of Pyrrosia lingua from Guizhou province on experimental renal calculus in rats

To screen the active fractions with lithagogue effects of Pyrrosia lingua from Guizhou province and preliminarily investigate its mechanism. The rats were fed with 1% ethylene glycol and 2% ammonium chloride to establish the nephrolithiasis models, which were used to evaluate thelithagogue effects of different polar fractions of P. lingua from Guizhou province. The level of urinary calcium and oxalic acid in urine, renal calcium, oxalic acid, superoxide dismutase (SOD), catalase(CAT) and malondialdehyde (MDA) in renal tissues,as well as crystalline deposit and lithogenesis in renal tissues and the levels of creatinine(Cr) and blood urea nitrogen (BUN) in the serum were detected. The effective compounds were inferred from the analysis of active fractions extract based on LC-MS technology. Petroleum ether fraction and dichloromethane fraction of P. lingua from Guizhou province can reduce renal oxalic acid and renal calcium concentration, increase urinary oxalic acid and urine calcium, with significant inhibitory effect on the formation of renal calculus in rats, significantly increase SOD and CAT activities in renal tissues, and significantly reduce MDA levels. LC-MS analysis showed that the caffeine, citric acid and tartaric acid among the compounds from petroleum ether fraction and dichloromethane fraction had lithagogue effects. Both the petroleum ether fraction and dichloromethane fraction of P. lingua from Guizhou province showed good effect on prevention and treatment of calculus in middle dose groups, and the mechanism may be associated with antioxidation, reducing calcium oxalate crystal deposition, and promoting calcium oxalatecrystal release, in addition, caffeine, citric acid and tartaric acid had lithagogue effects.

Sulfamethoxazole degradation by combination of advanced oxidation processes

The degradation of the antibiotic sulfamethoxazole (SMX) was studied by several oxidation processes in the same reactor and under identical experimental conditions. The evolution of SMX concentration and mineralization degree, as well as toxicity of the treated solutions were the parameters considered to assess the efficiency of the different oxidation processes. The formation of molecular, radical and ion intermediates was also monitored. Ozonation was the most efficient process in SMX degradation, while photo–ozonation, with or without H2O2, led to the highest mineralization (83% after 3 h), confirming the synergistic effect when ozone and light were applied together. The results suggested that the first intermediate formed during the degradation of SMX was 3-amino-5-methylisoxazole, the direct O3 attack being then the main responsible for its degradation. During the photolysis process p-benzoquinone was formed, although after 3 h of reaction this intermediate was no longer detected. The formation of two refractory acids, oxalic (OXL) and oxamic (OXM), was confirmed during SMX degradation and the presence of O3 and radiation together was mandatory to remove these compounds. When O3 and light were combined, all nitrogen and sulphur present in SMX molecule were converted into NH4+, NO3− and SO42−, respectively. Although photo-ozonation was the most efficient process in converting SMX, a considerable toxicity was developed in the treated solution, suggesting the formation of intermediates more toxic than the parent molecule.