The global presence of pharmaceutical pollutants in water sources represents a burgeoning public health concern. Recent studies underscore the urgency of addressing this class of emerging contaminants. In this context, our work focuses on synthesizing a composite material, FeO/MAF-32, through a streamlined one-pot reaction process, as an adsorbent for diclofenac, an emerging environmental contaminant frequently found in freshwater environments and linked to potential toxicity towards several organisms such as fish and mussels.
View Article and Find Full Text PDFThe photocatalytic decomposition of caffeine under UV-light irradiation was observed for the first time in a matrix of synthetic urine using granules of hydrogenated and iron-exchanged natural zeolite, coated with two loadings of TiO. A natural clinoptilolite-mordenite blend was used to prepare photocatalytic adsorbents coated with TiO nanoparticles. The performance of the obtained materials was tested in the photodegradation of caffeine, a water contaminant of emerging concern.
View Article and Find Full Text PDFIn this research, changes in several characteristics of partially reduced titania were studied. The reduction process used made it possible to gradually observe changes in the material depending on the amount of reducing agent used. We used NaBH to impregnate commercial TiO with isopropyl alcohol.
View Article and Find Full Text PDFZeolites are not often used directly as photocatalysts. Their framework and nanocavities have served as support or hosts for photoactive materials or traces of transition metals functioning as photoactive sites for catalysing decomposition and oxidation reactions in the gas phase. Research in this area has been limited to a few synthetic zeolites and in this context, efforts are directed to the preparation of new zeolite-based photocatalysts, when in nature there is an abundance of materials with properties yet to be discovered.
View Article and Find Full Text PDFConotrachelus dimidiatus (Coleoptera: Curculionidae) interacts with immature guava fruits (Psidium guajava L.) for feed, sleep, mate and oviposit. Determination of the volatile organic compounds (VOCs) emitted by the insect and immature fruits can help improve understanding of plant-insect and intraspecific insect interactions between females and males of C.
View Article and Find Full Text PDFImmature guava fruits (Psidium guajava L.) of commercial orchards in Mexico are affected by adults of Conotrachelus dimidiatus (Champion) causing economic losses to producers. The aim of this study was to assess the behavioral and electrophysiological responses of the weevil to selected semiochemicals emitted by the host plant fruit and to conspecifics.
View Article and Find Full Text PDFThe mature larva and pupa of Conotrachelus dimidiatus Champion, 1904 (Curculionidae: Molytinae) are morphologically re-described, keyed and, for the first time, compared with known larvae and pupae of other Conotrachelus species. The chaetotaxy of the larval and pupal body in the genus Conotrachelus is probably strictly uniform. The immature stages of described species are also compared with available data on the immature stages of genera from several tribes in the subfamily Molytinae.
View Article and Find Full Text PDFIntroduction: Determination of the volatile organic compounds (VOCs) emitted by immature fruits furthers our understanding of plant-pest interactions and by fruits in a ripe state concerns food quality.
Objectives: To apply headspace solid-phase microextraction gas chromatography quadrupole time-of-flight mass spectrometry (HS-SPME-GC-QTOF/MS) to compare the volatiles emitted by different parts of guava (Psidium guajava L. cv.
Carbofuran is a toxic carbamate pesticide, and its use has increased in recent years. While marketing information indicates stability in different chemical media, carbofuran exhibits relative photolability. The aim of this research was to decompose carbofuran and to identify the photoproducts achieved when two different doped titania photocatalysts were employed under UV irradiation.
View Article and Find Full Text PDFEnviron Sci Pollut Res Int
March 2017
Three carbon samples were employed in this work, including commercial (1690 m g), activated carbon prepared from guava seeds (637 m g), and activated carbon prepared from avocado kernel (1068 m g), to study the adsorption of the following gadolinium-based contrast agents (GBCAs): gadoterate meglumine Dotarem®, gadopentetate dimeglumine Magnevist®, and gadoxetate disodium Primovist®. The activation conditions with HPO were optimized using a Taguchi methodology to obtain mesoporous materials. The best removal efficiency by square meter in a batch system in aqueous solution and model urine was achieved by avocado kernel carbon, in which mesoporosity prevails over microporosity.
View Article and Find Full Text PDFApplications of carbon-TiO2 materials have attracted attention in nanotechnology due to their synergic effects. We report the immobilization of TiO2 on carbon prepared from residues of the plant Manihot, commercial TiO2 and glycerol. The objective was to obtain a moderate loading of the anatase phase by preserving the carbonaceous external surface and micropores of the composite.
View Article and Find Full Text PDFCarbon-TiO2 composites were obtained from carbonised Manihot dulcis waste and TiO2 using glycerol as an additive and thermally treating the composites at 800 °C. Furthermore, carbon was obtained from manihot to study the adsorption, desorption and photocatalysis of carminic acid on these materials. Carminic acid, a natural dye extracted from cochineal insects, is a pollutant produced by the food industry and handicrafts.
View Article and Find Full Text PDFCarbon-TiO2 sulfated composites were obtained from TiOSO4 · xH2O and glycerol as the TiO2 and carbon sources, respectively. The precursor xerogels were prepared in a one-step ultrasonic-assisted sol-gel reaction, followed by thermal treatment at 400°C under a nitrogen atmosphere to produce carbon-TiO2 sulfated composites. XRD, micro-Raman, SEM, and TEM studies showed that the composites consisted of nanocrystalline clusters of TiO2 and carbon.
View Article and Find Full Text PDFA set of organoarsenicals were identified in aqueous phenylarsonic acid (PA) and o-arsanilic acid (AA) solutions treated with soil of volcanic origin in batch systems. The transformation products were separated by liquid chromatography (RP-LC) and identified with element selective inductively coupled plasma-mass spectrometry (ICP-MS) as well as molecular selective electrospray ionization-mass spectrometry (ESI-MS) detection after their HPLC separation. The identification of the main degradation products by means of ESI-MS, ESI-MS/MS and ESI-TOF-MS showed the occurrence of nitrophenylarsonic acid and methylphenylarsinic acid in the solutions containing AA and PA in contact with soils, respectively.
View Article and Find Full Text PDFFive sulfonyl aromatic alcohols, namely 4-((2-hydroxyethyl)sulfonyl)phenol, 4-((2-(2-((4-hydroxyphenyl)sulfonyl)ethoxy)vinyl)sulfonyl)phenol, 4-(ethylsulfonyl)phenol, 4-(vinylsulfonyl)phenol and 5-((4-aminophenyl)sulfonyl)-2-penten-1-ol were identified by LC-ESI-Qq-TOF-MS as products formed by electrolysis of the bisazo reactive dye Reactive Black 5 (RB5). Since electrolyses were performed in an undivided cell equipped with Ni electrodes in alkaline medium, amines like 4-(2-methoxyethylsulfonyl)benzene-amine (MEBA) with m/z 216 were also suspected to be formed due to the plausible chemical reaction in the bulk or the cathodic reduction of RB5 and its oxidation by-products. Aiming to check this hypothesis, a method was used for the preparation of MEBA with 98% purity, via chemical reduction also of the dye RB5.
View Article and Find Full Text PDFSorption of phenylarsenicals including 4-hydroxy-3-nitrophenylarsonic acid (roxarsone), an animal feed additive widely used for growth stimulation, on soils was investigated in batch systems. Phenylarsonic acid, o-arsanilic acid and roxarsone were retained differently by unpolluted, non-sterilized soils. Sorption isotherms were analyzed by the Henry, Tóth and Langmuir-Freundlich equations.
View Article and Find Full Text PDFIn this study the husk of mango seed and two carbonaceous adsorbents prepared from it were used to study the adsorption behavior of eight acid dyes. The adsorbed amount in mmol m(-2) decayed asymptotically as the molecular volume and area increased. The interaction between the studied dyes and the mesoporous carbon was governed by the ionic species in solution and the acidic/basic groups on the surface.
View Article and Find Full Text PDFThe preparation of carbon from waste materials is a recent and economic alternative for the removal of dyes. In this study four samples of carbon were obtained by thermal treatment at 1000 degrees C using as precursor the guava seed with different particle sizes. The Taguchi method was applied as an experimental design to establish the optimum conditions for the removal of acid orange 7 in batch experiments.
View Article and Find Full Text PDFThe guava seed (SEGUVE) was characterized by ultimate and proximate analysis. In SEGUVE the principal thermal effect occurred at 363 degrees C and this can be attributed to the cellulose degradation, which was the main component ( approximately 61%). The guava seed has an acidic character with a high content of bulk functional groups (CO) and these characteristics were affected by carbonization.
View Article and Find Full Text PDFCombined detection by inductively coupled mass spectrometry (ICP-MS) for elemental information (quantification) and electrospray ionization mass spectrometry (ESI-MS) for molecular information (identification) by means of splitting of the eluent after chromatographic separation is a suitable means of analysis for unknown and not commercially available arsenic species. Simultaneous parallel ESI-MS and ICP-MS detection was applied to identify possible metabolites during the interaction of arsenobetaine (AsB) with natural zeolites. AsB, mainly produced by freshwater and marine organisms, is known to be a candidate of low toxicity.
View Article and Find Full Text PDFCalculation of the HPLC chromatographic retention times of different carotenoids supported our improved chromatographic separation of beta-carotene and lutein in four tomatoes and two tomatillo varieties in fresh form and after three different cooking procedures: pot boiling, cooking in a pressure cooker and microwaving. A good separation was achieved experimentally using an Ultrasphere ODS column and gradient elution with an acetonitrile-tetrahydrofuran-water mobile phase. It was shown that diverse tomato species contained different amounts of beta-carotene (6-400 microg/100 mg) and lutein (2-30 microg/100 mg).
View Article and Find Full Text PDFThe surface chemistry of maize naturasorbent was altered in this work by the modifying agents: phosphoric acid and different amines (triethanolamine, diethylenetriamine and 1,4-diaminobutane). Removal of methyl orange (25 mg l(-1)) was <50% by maize corn cobs modified by phosphorylation and higher by the quaternized samples: 68% with the 1,4-diaminobutane and 73% with the diethylenetriamine modificators. Adsorption of arsenite by the samples modified with phosphoric acid/ammonia was 11 microg g(-1), which corresponds to 98% removal from a 550 microg As l(-1) solution for an adsorbent dose of 50 mg ml(-1).
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