Publications by authors named "K Bhuvaneswari"

13 Publications

An efficient and magnetically recoverable g-CN/ZnS/CoFeO nanocomposite for sustainable photodegradation of organic dye under UV-visible light illumination.

Environ Res 2021 Jun 17;201:111429. Epub 2021 Jun 17.

Advanced Materials Research Chair, Chemistry Department, College of Science, King Saud University, Riyadh, 11451, Saudi Arabia.

Effective improvement of an easily recoverable photocatalyst is equally vital to its photocatalytic performance from a practical application view. The magnetically recoverable process is one of the easiest ways, provided the photocatalyst is magnetically strong enough to respond to an external magnetic field. Herein, we prepared graphitic carbon nitride nanosheet (g-CN), and ZnS quantum dots (QDs) supported ferromagnetic CoFeO nanoparticles (NPs) as the gCN/ZnS/CoFeO nanohybrid photocatalyst by a wet-impregnation method. The loading of CoFeO NPs in the g-CN/ZnS nanohybrid resulted in extended visible light absorption. The ferromagnetic g-CN/ZnS/CoFeO nanohybrid exhibited better visible-light-active photocatalytic performance (97.11%) against methylene blue (MB) dye, and it was easily separable from the aqueous solution by an external bar magnet. The g-CN/ZnS/CoFeO nanohybrid displayed excellent photostability and reusability after five consecutive cycles. The favourable band alignment and availability of a large number of active sites affected the better charge separation and enhanced photocatalytic response. The role of active species involved in the degradation of MB dye during photocatalyst by g-CN/ZnS/CoFeO nanohybrid was also investigated. Overall, this study provides a facile method for design eco-friendly and promising g-CN/ZnS/CoFeO nanohybrid photocatalyst as applicable in the eco-friendly dye degradation process.
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http://dx.doi.org/10.1016/j.envres.2021.111429DOI Listing
June 2021

Preparation and Characterization of Mg Doped ZnAI₂O₄Spinel Nanoparticles.

J Nanosci Nanotechnol 2021 Nov;21(11):5659-5665

Surfactant Research Chair, Chemistry Department, College of Science, King Saud University, Riyadh 11451, Kingdom of Saudi Arabia.

In the present study, combustion technique is adopted to study the impact of Mg ion doping on ZnAI₂O₄ nanoparticles (NPs). L-arginine is used as a fuel component. The Mg ions play a pivotal role in persuading various characteristics of ZnAI₂O₄ NPs. Various characterization technqiues such as Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), energy dispersive X-ray analysis (EDX), high resolution scanning electron microscopy (HR-SEM), diffuse reflectance spectroscopy (DRS), Thermo-gravimetric/differential thermal analysis (TG-DTA) and vibrating sample magnetometer (VSM) were carried out in order to synthesize the nanoparticles. Single phase cubic spinel structure of ZnAl₂O₄ (gahnite) formation was confirmed from the XRD characterization process of the nanoparticles. Estimated average crystallite size range of 11.85 nm to 19.02 nm was observed from Debye-Scherrer. Spherical morphology with uniform distributions was observed from HR-SEM characterization images. From the band gap studies, the attained band gap values were found to lie within 5.41 eV-4.66 eV range. The ZnAl₂O₄ and Mg:ZnAl₂O₄ NPs exhibited super-paramagnetic nature confirmed by magnetic measurements. The obtained results make ZnAl₂O ₄and Mg:ZnAl₂O₄ NPs appropriate for various optical, catalytic, energy and data storage applications.
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http://dx.doi.org/10.1166/jnn.2021.19478DOI Listing
November 2021

Analysis of tebuconazole residues in coconut water, kernel and leaves using LC-MS/MS.

Food Chem 2021 Oct 22;359:129920. Epub 2021 Apr 22.

Directorate of Plant Protection Studies, Coimbatore, India.

A method was validated for determining tebuconazole residues in coconut water, kernel and leaves using Liquid chromatography-Mass spectrometry/Mass spectrometry (LC-MS/MS) with electro spray ionization in positive ion mode. Samples were extracted with acetonitrile and subsequent clean-up was done using dispersive solid phase extraction. Recovery ranged between 70 and 114.39 % and the RSD was between 0.64 and 10.24 %. Root feeding studies with tebuconazole @ 5 and 10 mL/100 mL of water/tree revealed the presence of tebuconazole residues in coconut leaves until three days after treatment but dissipated to below quantifiable limit on 5th day at single dose while the residues went below quantifiable limit after 10 days at double the dose. Residues were below quantifiable limit in coconut water and kernel until three days. Data obtained from the study were used for estimating the risks associated with the exposures to tebuconazole residues in coconut.
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http://dx.doi.org/10.1016/j.foodchem.2021.129920DOI Listing
October 2021

Visible light driven reduced graphene oxide supported ZnMgAl LTH/ZnO/g-CN nanohybrid photocatalyst with notable two-dimension formation for enhanced photocatalytic activity towards organic dye degradation.

Environ Res 2021 06 26;197:111079. Epub 2021 Mar 26.

Chemistry Department P. O. Box 84428, College of Science, Princess Nourah bint Abdulrahman University, Riyadh, 11671, Saudi Arabia.

In this study, 2D/2D/2D heterostructured r-GO/LTH/ZnO/g-CN nanohybrid were synthesized through hydrothermal method. The strong electrostatic interaction between the negatively charged g-CN and r-GO nanosheets with positively charged layered triple hydroxide (LTH) nanosheets are effectively influences the successful formation of heterojunction. The LTH nanosheets are well spread on the g-CN nanosheets combined with r-GO. In particular, the as prepared heterojunction shows a better photocatalytic degradation activity compared to pristine samples and the significant enhancement in the photocatalytic performance is mainly accredited to the large interfacial charge transition of photogenerated charge carriers under the visible light irradiation. Although the 2D/2D/2D heterojunction effectively hinders the charge carrier recombination resulting high photocatalytic activity with good stability. In addition, the r-GO supported LTH/ZnO/g-CN heterojunction shows high photo-stability after sequential experimental runs with no obvious change in the dye degradation process. Consequently, the role of active species was investigated over the r-GO/LTH/ZnO/g-CN heterojunction with the help of different scavengers.
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http://dx.doi.org/10.1016/j.envres.2021.111079DOI Listing
June 2021

Construction of magnetically recoverable ZnS-WO-CoFeO nanohybrid enriched photocatalyst for the degradation of MB dye under visible light irradiation.

Chemosphere 2021 Jun 19;273:129687. Epub 2021 Jan 19.

Department of Physics, Vellore Institute of Technology (Amaravati Campus), Amaravati, 522501, Guntur, Andhra Pradesh, India.

Easily recyclable photocatalysts have received considerable attention for their practical application, in order to address the wastewater treatments. Here, we report efficient and magnetically recyclable ZnS-WO-CoFeO nanohybrid prepared through wet impregnation method. The photophysical and optical properties of as-prepared photocatalysts was investigated by different spectroscopic techniques. The photocatalytic activity of as synthesized samples were assessed by the photodegradation of methylene blue (MB) dye under visible light irradiation. Amongst, ZnS-WO-CoFeO nanohybrid exhibit higher photodegradation activity than the other bare and hybrid samples. The enhanced light absorption and lower emission intensity provide the improved photocatalytic activity of ZnS-WO-CoFeO nanohybrid. The ZnS-WO-CoFeO nanohybrid exhibit excellent photostability after four consecutive cycles. The ferromagnetic behavior of the hybrid sample using easily recover from the dye solution using an external bar magnet.
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http://dx.doi.org/10.1016/j.chemosphere.2021.129687DOI Listing
June 2021
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