High aspect ZnO nanorod growth over electrodeposited tubes for photocatalytic degradation of EtBr dye.

Hrudaya Jyoti Biswal,Anshul Yadav,Pandu R. Vundavilli,Ankur Gupta

doi:10.1039/d0ra08124h

Abstract

In this work, vertically grown rod type ZnO nanostructures have been synthesized on metallic nickel tube films fabricated through the cost-effective process of electroforming. The use of tubular metal substrates for the growth of ZnO nanorods has been found to be advantageous for the photocatalytic degradation of EtBr dye because of their high surface area-to-volume ratio. The nickel tubes with ZnO nanorods were characterized using X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). The developed system was utilized for the photocatalytic degradation of EtBr dye and its efficacy was revealed through the comprehensive mineralization of the dye within 150 min. The mechanism of the degradation process has been revealed through total organic carbon (TOC), chemical oxygen demand (COD) and high-performance liquid chromatography (HPLC) studies. A substantially lower amount of the photocatalyst has been used because of the homogeneously distributed growth of nanorods on the substrate. Density functional theory-based analysis has also been performed to study the photocatalytic degradation and adsorption properties of EtBr on ZnO nanorods. Using first principles DFT theory, geometry optimizations and vibrational analysis are performed which show a negative charge transfer from the substrate to the photocatalyst. For the first time this article reports the use of DFT analysis for investigating the adsorption of EtBr on ZnO nanorods, and the experimental growth of nanorods over electroformed Ni tubes.

Highlights

Ethidium bromide (EtBr, 3,8-diamino-6-phenyl-5ethylphenanthridine bromide, as shown in Fig. 1) is an aromatic, non-volatile compound having a tricyclic structure with an aniline on either side of a pyridine
We report the synthesis and characterization of ZnO nanostructures on nickel micro-tubes
In order to fabricate the metallic tubular lms and for the subsequent development of nanoseeds and nanorods, the chemical reagents used are nickel sulphate (NiSO4$6H2O), nickel chloride (NiCl2$6H2O), boric acid (H3BO3), zinc acetate dihydrate (Zn(CH3COO)2$2H2O), zinc nitrate hexahydrate (Zn(NO3)2$6H2O), hexamethylenetetramine (HMTA, (CH2)6N4), potassium hydroxide (KOH) and acetone. All these chemicals were procured from Central Drug House (CDH), Delhi, India while isopropyl alcohol (IPA) and glacial acetic acid (>99.99%) were purchased from Merck Limited, Mumbai

Summary

Introduction

Ethidium bromide (EtBr, 3,8-diamino-6-phenyl-5ethylphenanthridine bromide, as shown in Fig. 1) is an aromatic, non-volatile compound having a tricyclic structure with an aniline on either side of a pyridine. The resemblance of the EtBr ring to the ring of DNA bases makes it an efficient nonradioactive marker for visualizing nucleic acids in electrophoretic and other gel-based techniques. The formation of van der Waals contacts with the base pairs of DNA and RNA is responsible for the mutagenic property of EtBr. The widespread popularity of the same chemical as a staining agent for nucleic acids makes its disposal from chemical laboratories a serious concern. Various EtBr elimination processes like chemical degradation, extraction, adsorption and bleaching[1] etc. It was not possible to achieve complete degradation using these processes.

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