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Local natural persimmons were used as a new precursor to synthesize carbon quantum dots (CQDs) by a brief and environment friendly strategy, hydrothermal method. The as-prepared CQDs were characterized by transmission electron microscopy, Fourier transform infrared spectroscopy, Ultraviolet-visible spectroscopy, as well as fluorescence spectrophotometer. The average diameter of CQDs was 2.5±0.5 nm with spherical shape and exhibited blue fluorescence with the maximum emission wavelength at 438 nm and excitation wavelength at 345 nm. The influences of pH and ionic strength on CQDs fluorescence were evaluated. Moreover, the CQDs were used for determination of Fe3+ by blue fluorescence quenching as the result of the interaction between Fe3+ and -OH, -COOH on the CQDs surfaces. The proposed CQDs displayed high selectivity and sensitivity of Fe3+ in comparison with other metal ions. Therefore, a good linear relationship was established with the Fe3+ concentration in the range of 0.6-400 μM. The correlation coefficient of the calibration curve was 0.996. The detection limit of the method was 0.56 μM. Eventually, the CQDs made from persimmons were used for determination of Fe3+ in actual water sample with satisfactory results and gave recoveries between 95.66% and 99.90%. The relative standard deviation was 1.20%-1.86%. The results demonstrated the potential towards diverse applications of the local persimmons.In the development of direct methanol fuel cell (DMFC) the fabrication of an anode comprising of a Pt or Pt-based bi or tri-metallic alloys nanoparticles on a suitable support material having higher stability, higher surface area, electrical conductivity and strong interaction is very important. learn more In the present work we have solved this problem by using a nanocomposite of reduced graphene oxide (rGO) and graphitic carbon nitride (g-C₃N₄) as the support material and deposited PtCo nanoparticles by in-situ chemical reduction. The electro-oxidation of methanol is carried out in an acidic medium. The electrochemical behaviour of as-synthesized PtCo/rGO-gC₃N₄ catalyst was found to be much superior to Pt/rGO-g-C₃N₄ catalysts towards electro-oxidation of methanol and is mainly due to the homogeneous dispersion of PtCo nanoparticles onto rGO-g-C₃N₄ nano composite, higher electrical conductivity and a strong interaction between metal nanoparticles and N group of the support material. By using the as-synthesized electro-catalyst the adsorption or poisoning of Pt due to CO is greatly reduced and more active Pt sites are created for the electro-oxidation of methanol. Thus, the as-synthesized electro-catalyst can be used as an efficient anode material in a direct methanol fuel cell.If not properly treated, water contaminated with chromium (Cr(VI)) and lead (Pb(II)) can cause severe damage to health due to the accumulation of those toxic metals in the human body. Therefore, in this work, three iron oxides, i.e., δ-FeOOH, cystine-functionalized δ-FeOOH (Cys-δ-FeOOH), and Fe₃O₄, were synthesized and used as adsorbents for Cr(VI) and Pb(II) in water. The results indicated that the Cr(VI) is best adsorbed on cys-δ-FeOOH followed by δ-FeOOH and Fe₃O₄. It was because of the enhanced interaction between Cr(VI) and the cysteine functional groups on the δ-FeOOH surface. The Cr(VI) adsorption capacity of cys-δ-FeOOH, δ-FeOOH, and Fe₃O₄ was 217, 14, and 8 mg g-1, respectively. On the other hand, Pb(II) was preferentially adsorbed directly on δ-FeOOH achieving a maximum Pb(II) adsorption capacity of 174 mg g-1. The Pb(II) adsorption capacity of cys-δ-FeOOH and Fe₃O₄ was 97 and 74 mg g-1, respectively. The Cr(VI) adsorption on cys-δ-FeOOH was best described by the Langmuir-Freundlich model, whereas Pb(II) adsorption on δ-FeOOH followed the Langmuir model. Both Cr(VI) and Pb(II) adsorption on the adsorbents was well-fitted to pseudo-second-order kinetics. The Cr(VI) was more quickly adsorbed by cys-δ-FeOOH (h0 = 0.10 mg g-1 min-1) while the initial adsorption rate of Pb(II) onto δ-FeOOH was significantly faster (h0 = 16.34 mg g-1 min-1). Finally, the synthesized adsorbents were efficient to remove Cr(VI) and Pb(II) from water samples of the Doce river after the environmental disaster of Mariana city, Brazil, thus showing its applicability to remediate real water samples.In this study, pulsed laser deposition method (PLD) was employed to grow MgxZn1-xO films on quartz substrates. The optimal deposition temperature of 300 °C for MgxZn1-xO film was decided and Mg0.38Zn0.62O, Mg0.56Zn0.44O and Mg0.69Zn0.31O films were grown respectively using MgxZn1-xO targets with different Mg contents (x = 0.3, 0.5 and 0.7). As-deposited Mg0.38Zn0.62O film possessed the mixed-phase (hexagonal and cubic phase) structure, appropriate band gap of 4.68 eV and smaller surface roughness of 1.72 nm, and the solar-blind photodetector (PD) based on it was fabricated. The key features of our PD are the cutoff wavelength of 265 nm lying in solar-blind band, lower dark current (Idark) of 88 pA, higher peak responsivity of 0.10 A/W and bigger Ilight/Idark ratio of 1688, which provide the new idea for the application of solar-blind PDs based on MgxZn1-xO films.In this paper, novel Ethylenediaminetetraacetic acid disodium salt (EDTA) functionalized magnetite/ chitosan nanospheres (Fe₃O₄/CS-EDTA) are synthesized by combining solvothermal method and chemical modification, and they are further applied as a kind of adsorbent to eliminate dye of methylene blue (MB) from wastewater. The properties as well as structure exhibited by the fabricated adsorbent are characterized through FTIR, XRD, TG and TEM, together with VSM. The impact exerted by sorption parameters (time of contact, initial dye concentration, temperature, etc.) on the adsorptions were evaluated in batch system. These results demonstrated that our magnetic materials held the adsorption capacity for MB of 256 mg g-1 (pH = 11), and the kinetic model of pseudo-second-order and the Langmuir model could make an effective simulation regarding the adsorption kinetics and isotherm, respectively. Besides, the external magnetic field can assist in easily separating dye adsorbed Fe₃O₄/CS-EDTA from solution for regeneration.