ascorbic-acid and methyl-orange

In the present study, the surface of multiwalled carbon nanotubes (MWCNT)s is modified by ascorbic acid (AA) (vitaminC) for their dispersion improvement in the starch matrix. Then, the starch-based nanocomposites (NCs) containing 3, 6 and 9wt% of AS modified MWCNTs (AA-MWCNT)s were fabricated via ultrasonication method. Characterization of the prepared NCs was accomplished by different techniques. The optimum MWCNT content for the generation of fine electrical conductivity was found to be about 3wt%, indicating better dispersion of AA-MWCNT with low amount of AA-MWCNT. The adsorption efficiency of starch/AA-MWCNTs NCs is examined using methyl orange (MO) as adsorbate. Finally, it is concluded that starch/AA-MWCNTs NC is an effective adsorbent for the uptake of MO dye from aqueous solution.

Topics: Ascorbic Acid; Azo Compounds; Nanocomposites; Nanotubes, Carbon; Starch

Herein, we present a simple and green method for the synthesis of gold nanoparticles (AuNPs) using the phytoproteins of spinach leaves. Under ambient sunlight irradiation, the isolated phytoprotein complex from spinach leaves reduces the gold chloride aqueous solution and stabilizes the formed AuNPs. As prepared nanoparticles were characterized by UV-visible spectroscopy, Fourier transform infra-red (FTIR) spectroscopy, zeta potential, transmission electron microscopy (TEM) and energy dispersive X-ray analysis (EDS). The surface plasmon resonance (SPR) maximum for AuNPs was observed at 520 nm. The zeta potential value estimated for the AuNPs is -27.0 mV, indicating that the NPs are well separated. Transmission electron micrographs revealed that the particles are spherical in nature with the size range from 10 to 15 nm. AuNPs act as a catalyst in the degradation of an azo dye, methyl orange in an aqueous environment. The reduction rate was determined to be pseudo-first order. Electrocatalytic efficiency of the synthesized AuNPs via this green approach was studied by chronoamperometry using ascorbic acid and hydrogen peroxide as a model compound for oxidation and reduction, respectively. Electrocatalytic studies indicate that the gold nanoparticles can be used to detect ascorbic acid and hydrogen peroxide in micromolar concentrations with response time less than 3s.

Topics: Ascorbic Acid; Azo Compounds; Catalysis; Electrochemical Techniques; Electrodes; Gold; Green Chemistry Technology; Hydrogen Peroxide; Metal Nanoparticles; Oxidation-Reduction; Particle Size; Photosynthesis; Plant Leaves; Plant Proteins; Spinacia oleracea

In recent years, considerable effort has been devoted to finding novel enzyme mimetics with improved catalytic activities. However, the insightful understanding of such catalytic process is still elusive. In this paper, we report for the first time a typical photoactive layer-structured BiOBr as a novel biomimetic catalyst possessing highly efficient intrinsic peroxidase-like activity. Moreover, we have experimentally achieved high dark peroxidase-like catalytic activity in BiOBr microspheres and provided some new insights into the light-enhanced peroxidase-like catalytic property. On the basis of a typical color reaction derived from catalytic oxidation of peroxidase substrates over BiOBr microspheres with H2O2, the simple and sensitive colorimetric assays for detection of H2O2, glucose and ascorbic acid were successfully established. More interestingly, the BiOBr microspheres showed strong ability towards activation of H2O2, displaying excellent dark catalytic activity for the degradation of organic dye. It is therefore believed that our findings in this study could open up the possibility of utilizing BiOBr as enzymatic mimics in biotechnology and environmental remediation.

Topics: Ascorbic Acid; Azo Compounds; Biocompatible Materials; Biosensing Techniques; Bismuth; Catalysis; Colorimetry; Coloring Agents; Glucose; Hydrogen Peroxide; Kinetics; Light; Microspheres; Oxidation-Reduction; Peroxidase; Water Pollutants, Chemical