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Anti-corrosive potential of Cyperus rotundus as a viable corrosion inhibitor for mild steel in sulphuric acid

Rajan Anitha (SNS College of Technology, Coimbatore, India)
Chan Basha Nusrath Unnisa (PSGR Krishnammal College for Women, Coimbatore, India)
Venkatesan Hemapriya (PSGR Krishnammal College for Women, Coimbatore, India)
Selvaraj Mohana Roopan (VIT University, Vellore, India)
Subramanian Chitra (PSGR Krishnammal College for Women, Coimbatore, India)
Ill-Min Chung (Konkuk University, Gwangjin-gu, Republic of Korea)
Seung-Hyun Kim (Konkuk University, Gwangjin-gu, Republic of Korea)
Prabakaran Mayakrishnan (Department of Crop Science, Konkuk University, Gwangjin-gu, Republic of Korea)

Pigment & Resin Technology

ISSN: 0369-9420

Article publication date: 17 April 2020

Issue publication date: 5 June 2020

159

Abstract

Purpose

Over the past decade, plant extracts are ultimate green candidatures to substitute the expensive and noxious synthetic corrosion inhibitors. In this regard, this study aims to focus on evaluating anti-corrosion properties of green inhibitor Cyperus rotundus (C. rotundus), a perennial herb found throughout India.

Design/methodology/approach

The biocompatible components present in C. rotundus extract was analyzed by gas chromatography–mass spectroscopy analysis. The corrosion inhibitory effect of C. rotundus was assessed by impedance, polarization and surface morphometric study [atomic force microscopy (AFM)]. Density functional theory (DFT) study was carried using DFT/B3LYP, and basis set used for calculations was 6-31G (d, p) using Gaussian 03 program package.

Findings

Predominant components such as octadecanoicacid, ethylester, n-hexadecanoic acid, pentanoicacid-4-oxoethyl ester, cyclotrisiloxane, hexamethyl, cyclotetrasiloxane and octamethyl were identified from the extract of C. rotundus. Impedance study demonstrated that the addition of inhibitor reduces the double-layer capacitance and increases the charge transfer resistance. Furthermore, polarization studies indicated that the extract of C. rotundus acted as a mixed-type inhibitor with decrease in corrosion current density with increase in concentration. AFM study evinced the formation of inhibitor film on mild steel surface. The donor–acceptor interactions of active sites of predominant phytoconstituents were substantiated by computational analysis (DFT).

Originality/value

This paper deals with the inhibition effect of extract of C. rotundus on mild steel in 0.5M H2SO4. C. rotundus has a capability to adsorb on the metal surface, thus hindering corrosion.

Keywords

Acknowledgements

This paper was supported by the KU Research Professor Program of Konkuk University.

Authors contribution: Rajan Anitha and Ill-Min Chung contributed equally to this work.

Citation

Anitha, R., Nusrath Unnisa, C.B., Hemapriya, V., Mohana Roopan, S., Chitra, S., Chung, I.-M., Kim, S.-H. and Mayakrishnan, P. (2020), "Anti-corrosive potential of Cyperus rotundus as a viable corrosion inhibitor for mild steel in sulphuric acid", Pigment & Resin Technology, Vol. 49 No. 4, pp. 295-304. https://doi.org/10.1108/PRT-11-2019-0101

Publisher

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Emerald Publishing Limited

Copyright © 2020, Emerald Publishing Limited

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