Synthesis and Characterization of TiO2 Modified with olystyrene and Poly(3-chloro-2-hydroxypropyl Methacrylate) as Adsorbents for the Solid Phase Extraction of Organophosphorus Pesticides

ARTICULO DE INVESTIGACION EN REVISTA INDEXADANovel hy br i d Ti O2 particles were developed and assessed as an adsorbent for solid phase extraction (SPE) of organophosphorus pesticides (fensulfothion, parathion methyl, coumaphos, and diazinon) from spiked water. Th sol-gel method was used to synthesize TiO2 particles, which were coated with free-radical polystyrene (PS) and poly(3-chloro-2-hydroxypropyl methacrylate) (PClHPMA) polymers. Particle structures were determined via Fourier transform infrared spectroscopy to confim that the polymers were successfully anchored to the TiO2 particles. Thrmogravimetric analysis was conducted to determine organic and inorganic matter in TiO2-PS and TiO2-PClHPMA particles showing results of 20 : 80 wt/wt% and 23 : 77 wt/wt%, respectively. SEMEDS and X-ray diffaction test were conducted to determine the morphology and semielemental composition of the particles showing amorphous characteristics. By observing the contact angle, particles coated with PClHPMA were determined to be more hydrophilic than TiO2-PS particles. Th pore size distributions obtained from the N2 adsorption-desorption isotherms were 0.150 and 0.168 cm3g−1. Th specifi surface area (BET) was 239.9 m2g−1 for TiO2-PS and 225.7 m2g−1 for TiO2-PClHPMA. Th synthesized particles showed relatively high yields of adsorption in SPE. Th pesticide recoveries obtained by high performance liquid chromatography ranged from 6 to 26% for TiO2-PClHPMA and 44 to 92% for TiO2-PS.Consejo Nacional de Ciencia y Tecnología, CONACyT (83390

Preparation of zinc peroxide nanoparticles by laser ablation of solid in liquids

In the last decade, there has been interest on the synthesis and characterization of Zinc peroxide (ZnO2) due to its potential applications as biocide, bactericide, inorganic oxidant and so on. ZnO2 can be obtained as a powder with a cubic structure and has been utilized as a precursor to obtain Zinc oxide (ZnO). ZnO2 can be considered as an oxygen reservoir since when it is heated at relatively low temperatures oxygen is released. Various approaches have been utilized to synthetize ZnO2 powders like sol-gel, organometallic precursors, hydrothermal, Laser Ablation of Solids in Liquids (LASL), and so on. While the hydrothermal route is one of the most utilized methods to obtain ZnO2, the LASL technique has only been utilized by the Gondal´s group to synthesize zinc peroxide nanoparticles. Escobedo et al. have been reported a study of the vibrational properties of ZnO2 NPs synthesized by the hydrothermal method. Additionally, they present results of XRD, TEM and by thermal analysis determine the decomposition temperature of their ZnO2 NPs. Recently, the Escobedo-Morales’s group has reported a green method to prepare ZnO nanostructures employing as starting material ZnO2 (prepared by hydrothermal method

Centro Conjunto de Investigación en Química Sustentable UAEM-UNAM

Se describe brevemente el origen del Centro Conjunto de Investigación en Química Sustentable UAEM-UNAM (CCIQS). Se presentan principalmente las actividades científicas que se desarrollan en este centro relacionadas con la nanociencia y la nanotecnología (NyN), y a los investigadores responsables de las mismas. Además, se relata de manera sucinta la importancia de la formación de recursos humanos a través de los programas de licenciatura y posgrado de la Facultad de Química de la UAEM

Influence of pH on properties of ZnS thin films deposited on SiO2 substrate by chemical bath deposition

Artículo Publicado en Revista indexadaThis work focuses on the study of zinc sulfide (ZnS) thin films prepared by chemical bath deposition. The effect of the pH ranging from 10.0 to 10.75 on quality of ZnS thin films on SiO2 substrate is investigated. The effect of pH on the surface showed that the variation of pH has a significant effect on the morphology of the ZnS thin films. The sample with pH value of 10.50 was uniform, free of agglomerates with band gap energy about 3.67 eV. The resistivity of ZnS thin films on SiO2 substrate with different pH value were about 107 Ω cm.DGAPA-PAPIIT IN108613-2 - PROYECTO UNA

Biogenic Silver Nanoparticles as Sensors of Cu2+ and Pb2+ in Aqueous Solutions

Biogenic Silver Nanoparticles as Sensors of Cu2+ and Pb2+ in Aqueous SolutionsSilver nanoparticles (Ag-NPs) were bio-synthesized using Camellia sinensis (green tea) aqueous extract. Nanoparticles prepared with 10-3 M AgNO3 solution, using 3mL of green tea extract and at 60˚C, have spherical shape with a mean diameter of 7nm. The formation of the nanoparticles was confirmed by UV-Vis spectrophotometry through studies of the surface plasmon resonance (SPR). The morphology, size and crystalline structure of the Ag-NPs were determined using high definition transmission electron microscopy (TEM). Moreover, these green synthesized Ag-NPs were found to exhibit good sensing properties towards Cu2+ and Pb2+ ions in aqueous solutions. This metal ions-sensing ability of the biogenic Ag-NPs was monitored by UV-Vis spectrophotometry (SPR analyses) and fluorescence spectroscopy

Shape Tuning of Magnetite Nanoparticles Obtained by Hydrothermal Synthesis: Effect of Temperature

Acknowledgments The authors acknowledge the Kleberg Advanced Microscopy Center (KAMiC) and NIH RCMI Nanotechnology and Human Health Core (Grant 5G12RR013646-12) at University of Texas at San Antonio for the support with electron microscopy. The authors gratefully acknowledge Dr. Elizande-Galindo and Dr. Farias Mancilla from UACJ for their technical support with magnetic measurements. This research was funded by UAEM Grant 3688/20147CIB and CONACYT Grant 280518. The authors thank the Cátedras-CONACYT program and the Facultad de Odontología, Universidad Autónoma Benito Juárez de Oaxaca, for their support. The authors also thank the financial support from DGAPA-UNAM: PAPIIT-IA205518 and PAPIME-PE208518.In this work, we present a simple and efficient method for pure phase magnetite (Fe3O4) nanoparticle synthesis. The phase structure, particle shape, and size of the samples were characterized by Raman spectroscopy (Rm), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray (EDS), and transmission electron microscopy (TEM). The morphology tuning was controlled by the temperature of the reaction; the nanoparticles were synthesized via the hydrothermal method at 120°C, 140°C, and 160°C, respectively. The Rm and XRD spectra showed that all the nanoparticles were Fe3O4 in a pure magnetite phase. The obtained nanoparticles exhibited a high level of crystallinity with uniform morphology at each temperature, as can be observed through TEM and SEM. These magnetic nanoparticles exhibited good saturation magnetization and the resulting shapes were quasi-spheres, octahedrons, and cubes. The samples showed striking magnetic properties, which were examined by a vibrating sample magnetometer (VSM). It has been possible to obtain a good morphological control of nanostructured magnetite in a simple, economical, and scalable method by adjusting the temperature, without the modification of any other synthesis parameter

Novel tuffite/Fe-Cu oxides nanocomposite with functionality for dye removal in aqueous solution

Fe-Cu oxides nanoparticles were embedded on tuffite (TUF) mineral by means of a simple immersion-ion impregnation, followed by a reduction reaction, methodology. TUF/Fe-Cu nanocomposite characteristics were investigated by XRD, TEM, BET, SEM, FT-IR spectroscopy and pHzpc method. Fe-Cu nanostructures with mean sizes between 10 and 20 nm were effectively supported on TUF. Because of its functional properties, the nanocomposite was studied as adsorbent material for the degradation of Malachite Green (MG) organic dye in aqueous solution. The adsorption kinetic data was well-fitted to pseudo first-order model, indicating physisorption as the main mechanism of adsorption. High pH and temperature of the solution favored malachite green adsorption. The adsorption process was spontaneous and endothermic. In comparative sorption experiments with different dyes, the nanocomposite showed better removal capacities for cationic and basic than for anionic and acid dyes. Langmuir, Freundlich, Langmuir-Freundlich and Temkin models were applied to evaluate the isotherms, resulting in an adsorption capacity of 376.66 mg/g, which is above most of the adsorbent materials so far employed for malachite green degradation in aqueous solution. Therefore, this novel, easy to prepare and low-cost nanocomposite proved to have synergic functionality as an efficient adsorbent material for cationic organic dyes.UAEM/2708/2013 and 3688/2014/CIB projects. Scholar-ship Grant No. 289993CONACYT

Reuse of sustainable materials for xylenol orange dye and copper (II) ion ammoniacal removal

Reuse of sustainable materials for xylenol orange dye and copper (II) ion ammoniacal removalWater pollution caused by heavy metals and organic compounds is an environmental problem with negative impact, making the restoration of water quality a priority. In this paper, the adsorption of xylenol orange dye (XO) on vitreous tuff mineral (VT) was studied. It was established that the adsorption capacity of VT was 45.17 mg/g. The removal was carried out by interactions between active sites on the surface of the material and the functional groups of the dye. The solid waste obtained from this process (VTXO) was reused as adsorbent material for Cu removal in the form of the complex Cu-NH3 because this process was done in an ammoniacal medium. It was found that the adsorption capacity of this new material was 33.09 mg/g. In a previous research, VT mineral was used to remove crystal violet (CV) instead of XO. The solid waste of this last process (VTCV) was also applied for Cu-NH3 removal, in order to compare the adsorption capacity of VT after the adsorption of two different kinds of dyes. The adsorption capacity of VTXO was lower than that of VTCV (71.23 mg/g). In both processes, adsorption kinetic was well described by a chemical adsorption onto a heterogeneous surface. The equilibrium time for XO removal was 50 min and 80 min for Cu-NH3. The experimental design stated that the maximum adsorption capacity was reached when the initial concentration was 6400 mg/L and the solid-liquid ratio was 10 g/L. The system that requires the least amount of adsorbent was the counter flow batch. Finally, it was possible to estimate the behavior of the system on a higher scale. This research provides an efficient and economical alternative to treat water contaminated with dyes and cooper in an ammoniacal medium using the same material in both processes, one after the other

Plasmonic and fluorescent sensors of metal ions in water based on biogenic gold nanoparticles

SE REPORTA LA CARACTERIZACION DE NANOPARTICULAS PLASMONICASGold nanoparticles (AuNPs) were synthesized using a rapid, single step, and completely green biosynthetic method employing aqueous Citrus paradisi (grapefruit) extract, which was used as both the reducing and capping agent. Au(III) ions were rapidly reduced by the aqueous grapefruit extract, leading to the formation of highly stable and crystalline colloidal AuNPs, confirmed by the surface plasmon resonance (SPR) peak centered at 544 nm in the UV–Vis spectra. Biogenic AuNPs have been evaluated as plasmonic, fluorescent and naked-eye sensors of Pb2+, Ca2+, Hg2+, Zn2+ and Cu2+ ions in aqueous media, with a good performance and selectivity. Of the three methods used for metal ions sensing, fluorescent sensors shows better results, specifically with Ca2+, Cu2+ and Pb2+. Copper was detected by both plasmonic and fluorescent methods