Corrosion Inhibition by Flower Extracts - At a Glance

A Suriya Prabha1, N Vijaya2, T Umasankareswari3, A Krishnaveni4, J Jeyasundari5, K Kavitha6, H Benita Sherine6,N Renuga Devi7 and Susai Rajendran8*

1Department of Chemistry, Mount Zion College of Engineering and Technology, Pudukkottai, India

2Department of Chemistry, Vellalar College for Women, Erode, India

3Department of Chemistry, Rajapalayam Raju’s College, Rajapalayam, India

4Department of Chemistry, Yadava College, Madurai, India

5PG and Research Department of Chemistry, Vellaichamy Nadar College, Madurai, India

6PG and Research Department of Chemistry, EVR Government Arts College, Trichy, India

7Department of Zoology, GTN Arts College, Dindigul-624 005, India

8Corrosion Research Centre, PG Department of Chemistry, St Antony’s College of Arts and Sciences for Women, Dindigul-624005,India (Affiliated to Mother Teresa’s University, Kodaikanal, India)

*Corresponding author:Dr. Susai Rajendran, Corrosion Research Centre, PG Department of Chemistry, St Antony’s College of Arts and Sciences for Women, Dindigul-624005, India (Affiliated to Mother Teresa’s University, Kodaikanal, India), E-mail: susairajendran@gmail.com

Citation: Susai Rajendran, et al (2020) Corrosion Inhibition by Flower Extracts - At a Glance J Chem Sci Chem Engg 1(1): 29-36.

http://dx.doi.org/10.47890/JCSCE/SRAJENDRAN/2020/10082115

Received Date: April 30, 2020;Accepted Date: May 13, 2020; Published Date: May 15, 2020

Abstract

Flower extract are ecofriendly corrosion inhibitors. They have been used to control corrosion of mild steel, copper and aluminium in various media. The mechanistic aspects have been investigated by electrochemical studies such as polarisaiton study and AC impedance spectra. The protective film has been analysed by FTIR, SEM, EDX and AFM. The adsorption isotherms isotherms being obeyed are Langmuir, Temkin and Freundlich adsorption isotherms. The flowers extract primarily function as mixed type of inhibitors. The active principles mainly present in colored flowers are anthocyanins, and carotenoids. They contain polar groups such as hydroxyl, methoxy and ether. These ingredients coordinate with the metal ions on the metal surface through oxygen atom, benzene ring and conjugated double bonds. The protective film formed on the metal surface controls the corrosion process.

Keywords: Corrosion Inhibition; Flower Extract; AFM; SEM; FTIR; Isotherms; Green Inhibitors

Introduction

Metals when they come in contact with water and air, they undergo decay. This process is called corrosion. Corrosion is a natural spontaneous process. It is a thermodynamically favourable process. Because of corrosion, there is collapse of bridges, industrial equipments, aeroplanes and ships. This leads to loss of life and shut down of industries. There are many ways to control corrosion process. One such method is use of inhibitors. Among the various types of inhibitors, extracts of plant materials are preferred since they are easily available, nontoxic and less expensive. In the present work the use of flower extracts as corrosion inhibitors is discussed.

Colors of flowers

Flowers have showy colors to attract pollinators such as bees, Hummingbirds, Butterflies, moths and bats. Each pollinator is attracted by specific color. For example, bright blue and violet colors attract bees. Red, pink, fuchsia or purple flowers attract Hummingbirds. Yellow, orange, pink and red colors attract Butterflies. The color of the flowers are due to chemical compounds such as anthocyanin’s (red, pink, blue and purple) (Figure 1, Table I) and carotenoids (Figure 2) (yellow, red and orange). The general structure of anthocyanin is shown in Figure 1. It contains glucose unit in position 3 and 5. When the glucose unit is removed then anthocyanidine is produced. It is also called agycon. When R1 and R2 are replaced by H, OH and OCH3, various ananthocyanins are produced.

Figure 1: General structure of Anthocyanin

Figure 2: Structure of β carotene

Table I: Various anthocyanins

Use of flower extracts as corrosion inhibitors

Introduction

Many researchers have recently focused on corrosion prevention methods using green inhibitors. However, the use of green inhibitors has proven to be the easiest and cheapest method for corrosion protection and prevention due to their low toxicity, easy availability and economical preparation. The study is conducted by some techniques such as weight loss method, electrochemical studies etc.

Metals and alloys

Flower extracts have been used to control corrosion of various metals and alloys [1-25]. For example the extracts have been used to control corrosion of mild steel [1,2,4-7 ], Aluminium [3,21,23] and copper [8].

Medium

The corrosion resistance of steel has been investigated in various medium such as acidic medium [1,3-7,14-20], alkaline medium [2], sea water [8], chloride medium [24] and industrial cooling water systems [25].

Flower extracts

Various types of flower extracts have been used as corrosion inhibitors. For example extracts of Rosa damascena flower [1], Primrose flower [2], Areca flower [3], Primula vulgaris flower [4], Borage flower [5] have been used as corrosion inhibitors.

Methods

Corrosion inhibition efficiencies have been evaluated by weight loss method [9,10,22,24,25]. Mechanistic aspects of corrosion inhibition have been studied by electrochemical studies [5,6,9,11,14,15,19,23-25] such as polarization study and AC impedance spectra. Cyclic Voltammetry [12] has also been employed.

Surface morphology of protective film

Corrosion inhibition is due to the formation of protective film formed on the metal surface. The protective film has been analysed by surface analysis techniques such as FTIR spectroscopy [2,5,6,11], X-ray analysis [2], Contact angle measurement [2,5], SEM [3,5,13], UV-Visible spectroscopy [4,5], Raman spectroscopy [12], EDAX [10] and AFM [3,5,24].

Adsorption isotherm

The film formation on the metal surface takes place after adsorption of inhibitor molecules on the metal surface obeys various isotherm such as Langmuir adsorption isotherm [1,3,5,6, 10,13,14,16, 17], Temkin adsorption isotherm [6, 18-20], Freundlich adsorption isotherms [22].

Findings

Inhibition of corrosion of mild steel in various media in presence of various types of flower extracts has been investigated by many techniques. The important findings are listed below. The inhibitors function as mixed type of inibitors [9,10,15,20] under the given experimental conditions. In electrochemical studies, when corrosion inhibition takes place linear polarization value increases, Corrosion current value decreases, Charge transfer value increases and Double layer capacitance value decreases [5,6,9,11,14,15,19,23-25].

Recent research on use of flower extracts as corrosion inhibitors

Many research activities have been carried out on the inhibition of corrosion by flower extracts. They are summarized in the following Table1.

Table1: Flower extracts as corrosion inhibitors

 

S.No

 

Metal

 

Medium

 

Inhibitor

 

Method

 

Findings

 

Ref

1

Mild Steel

1 M HCl

Rosa damascena flower extract

PPS ,  SEM and AFM

Inhibition efficiency 90%, Langmuir isotherm

1

2

Mild Steel

Saline solutions

Primrose flower (PPE)  extract and zinc cations

FT-IR, SEM, UV–Vis,  GIXRD,  AFM,  CA, EIS,  PPS

Inhibition efficiency 95.3%

2

3

Aluminum

0.5 M HCl

Areca flower extract

Weight loss, EIS, SEM and AFM

Langmuir adsorption model

3

4.

Mild Steel

1 M HCl

Primula vulgaris flower extract

FT-IR,  UV–Vis, SEM,  CA, EIS and  PDS

Inhibition capacity 95.5% at1000 ppm PVFE

4

5.

Mild Steel

1 M HCl

Borage flower extract

PPL, EIS,   AFM ,  SEM FT-IR, UV–Vis and  contact angle  measurement

Langmuir isotherm, 91% efficiency at 800 ppm after 5 h

5

6.

Mild Steel

1M HCl

Tithonia diversifolia flower extract

Weight loss, EIS,  PPL, FT-IR and OES

Langmuir and Temkin adsorption isotherms

6

7.

Mild Steel

Acid medium

Dipteracanthus prostratus (POIR)and Tithonia diversifolia flower extract

Thermal & dielectric spectroscopic method

Corrosion inhibition

7

8.

Copper

Natural   sea water

Ziziphus lotus

Weight loss, polarization study, SEM

93% inhibition efficiency

8

9

Mild Steel

1M HCl

Olive inflorescence flower extract

Weight loss, PPL, EIS and IR

Mixed inhibitor

9

10

Mild Steel

1.0 M phosphoric acid

Borage flowers aqueous extract

HE, ML, PDP, SEM and EDX

Langmuir and thermodynamic-kinetic adsorption isotherms, Mixed-type inhibitor

10

11

Mild Steel

1 N HCl

Gloriosa superba Linn. extract

ML, PPL, EIS, FTIR and  SEM

Temkin adsorption isotherm,
99.80 % at 15 ppm

11

12

Reinforcing steel

3.5% NaCl

Tagetes erecta extract

In situ and ex situ Raman spectroscopy,  CV,  OCP and  EIS

Raman method

12

13

Mild Steel

0.5 M H2SO4

Bombax ceiba flower extract

PPL, SEM and ML

Langmuir adsorption isotherm,  Mixed-type behaviour, Inhibition efficiency 90.84 %

13

14

Mild Steel

1M HCl

Opuntia Ficus Indica methanolic flowers extract

ML, PPL and  EIS

Langmuir's adsorption isotherm

14

15

Mild Steel

1M HCl

Canna Indica flower extract

ML, PPL and  EIS

Mixed type inhibitor

15

16

Mild Steel

0.5M  H2SO4

Tagetes erecta extract

Gravimetric, PPL and  EIS

Langmuir adsorption isotherm,  Mixed inhibitor

16

17

Mild Steel

0.5 M H2SO4

Anacyclus pyrethrum L. extracts

PPL and  EIS

Langmuir adsorption isotherm

17

18

Mild Steel

1 N H2SO4

Musa acuminata flower extract

ML, PPL, SEM

Temkin adsorption isotherm,  Maximum efficiency of 95.01% for 5 hours

18

19

Mild Steel

1 N HCl

Musa acuminata flower extract

ML, PPL and EIS

Langmuir and Temkin adsorption isotherms,  mixed type inhibitor

19

20

Mild Steel

1M HCl

Cocos Nucifera Flower extract

ML, PPL,  Tafel, lpr,eis,

Langmuir and Temkin type isotherms,  Inhibition efficiency 97.3%,  mixed type inhibitor

20

21

Mild Steel and  Aluminium

2M HCl

Nerium oleander and Tecoma stans Air dried flowers

Chromatography and Spectral studies

Corrosion inhibition. Antibacterial and antifungal activity against different organisms

21

22

Mild Steel

1 M HCl

Cassia Auriculata flowers extract

ML, electrochemical studies

Langmuir, Temkin, Freundlich and thermodynamic model,  Mixed type inhibitor,  inhibition efficiency74.7%

22

23

Aluminium

pH 12

Hibiscus rosa-sinensis

ML, PPL,EIS and  FTIR

Inhibition efficiency 98%

23

24

Carbon steel

60 ppm of Cl-

Hibiscus rosa-sinensis Linn  flower extract

ML, PPL,EIS,  UV-vis,  FT-IR and AFM

Mixed type inhibitor

24

25

Mild Steel

Industrial  cooling systems

Eucalyptus (leaves), Hibiscus (flower), and Agaricus extracts

Weight loss and Polarization methods

Langmuir and Freundlich adsorption isotherms,  Mixed inhibitors

25


Uses of flower extracts

For several centuries, medical practitioners have lengthy mentioned the therapeutic properties of certain flora. Extra than simply spanning time, this information additionally spans many cultures around the world. One of the finest blessings is that plants and plants offer absolutely herbal medicinal homes, frequently without the frightening side outcomes that current pills and medicines bring on. Furthermore, treatments crafted from plants can be a good deal less expensive than tablets marketed by using pharmaceutical companies. There are many uses from the flower extracts. They are summarized in the following Table 2.


Table 2: Uses of flower extracts

S.No

Name of the Flower

Medicinal Uses

Ref

1

Rosa damascena flower extract

Treatment of abdominal and chest pains, strengthening the heart, menstrual bleeding, digestive problems and constipation

26

2

Primrose flower (PPE)  extract

During pregnancy for preventing high blood pressure (pre-eclampsia), shortening labor, starting labor, and preventing late deliveries, premenstrual syndrome (PMS), breast pain, and symptoms of menopause such as hot flashes

27

3

Areca flower extract

Relieves hunger, abdominal discomfort and weariness, veterinary medicine to expel tapeworms, used against anaemia, fits, leucoderma, leprosy, obesity and worms

28

4.

Primula vulgaris flower extract

Spasms, cramps, paralysis and rheumatic pains

29

5.

Borage flower extract

Fever, cough, and depression, hormone problem, blood purification, to increase urine flow, to prevent inflammation of the lungs, as a sedative, and to promote sweating

30

6.

Tithonia diversifolia flower
extract

Treatment of constipation, stomach pains, indigestion,   sore throat and liver pains

31

7.

Dipteracanthus prostratus (POIR) neem leaves and Tithonia diversifolia flower extract

Treatment of constipation, stomach pains, indigestion, sore throat and liver pains

32

8.

Ziziphus lotus

Improving muscular strength and weight, for preventing liver and bladder diseases and stress ulcers, and as a sedative. It is also used to reduce constipation

33

9

Olive inflorescence flower extract

Reduces symptoms of constipation such as bloating, stomach pain, lower the  total cholesterol, low-density lipoprotein and  reduce levels of bilirubin

34

10

Gloriosa superba Linn. extract

In intermittent fevers, wounds. Antifertility purpose, Gonorrhea, Leprosy, Piles, Debility, dyspepsia, flatulence, haemorrhoids, helminthiasis, inflammations, in promoting labor pain and expulsion of the placenta

35

11

Tagetes erecta extract

To treat boils, carbuncles and earaches,  treat colds, mumps, skin diseases, conjunctivitis and sore eyes

36

12

Bombax ceiba flower extract

Treatment of cholera, tubercular fistula, coughs, urinary complaints, nocturnal pollution, abdominal pain due to dysentery, and impotency

37

13

Opuntia Ficus Indica methanolic flower extract

Treatment of chronic diseases, particularly diabetes, obesity, cardiovascular diseases, and cancer

38

14

Canna Indica flower extract

Treatment of gonorrhoea and amenorrhoea

39

15

Anacyclus pyrethrum L. extracts

To treat antidiabetic, antioxidant, treating asthama, cardiac diseases, and throat problems, remove laziness, nerves weakness, carminative, stomache, arthritis, sciatica, diuretic, tooth and gum problems, aphrodisiacs, hiccoughs, epilepsy, headache, pains, muscle relaxant, worm infestation, anti-rheumatism, anticonvulsant, brain tonic, common cold and other human related disorders

40

16

Musa acuminata flower extract

Treatment of diseases like diabetes, hypertension, cancer, ulcers, diarrhoea, urolithiasis, Alzheimer's and infections. Other medicinal uses are in surgical dressing, pain relief, food and pharmaceuticals, nano medicine, pollution control, apoptosis and cell cycle

41

17

Cocos Nucifera Flower extract

To treat rheumatism and back pains or as an ointment to maintain smooth, soft skin, sick new born infants and women who have just given birth

42

18

Nerium oleander and Tecoma stans Air dried flowers

Treatment of heart conditions, asthma, epilepsy, cancer, painful menstrual periods, leprosy, malaria, ringworm, indigestion, and venereal disease; and to cause abortions

43

19

Cassia Auriculata flowers extract

Good for skin, reduces obesity, constipation, regulates, menstrual Cycle, antidiabetic and antihelmintic Properties

44

20

Hibiscus rosa-sinensis

To treat heart and nerve diseases, and as a diuretic to increase urine production, to treat constipation, cancer, liver disease, and cold symptoms

45

21

Eucalyptus (leaves), Hibiscus (flower), and Agaricus extracts

To relieve a sore throatsinusitis, and bronchitis

46

Conclusions

A review of use of flower extracts as corrosion inhibitors have discussed. The various aspects presented are as follows:

  • Flower extract are ecofriendly corrosion inhibitors.
  • They have been used to control corrosion of mild steel, copper and aluminium in various media.
  • The mechanistic aspects have been investigated by electrochemical studies such as polarization study and AC impedance spectra.
  • The protective film has been analysed by FTIR, SEM, EDX and AFM.
  • The adsorption isotherms isotherms being obeyed are Langmuir, Temkin and Freundlich adsorption isotherms.
  • The flowers extract primarily function as mixed type of inhibitors.
  • The flowers have medicinal values apart from fragrance.

Mechanism of corrosion inhibition

  • The active principles mainly present in colored flowers are anthocyanins, and carotenoids.
  • They contain polar groups such as hydroxyl, methoxy and ether.
  • These ingredients coordinate with the metal ions on the metal surface through oxygen atom, benzene ring and conjugated double bonds.
  • The protective film formed on the metal surface controls the corrosion process.

Acknowledgement

The authors are thankful to their respective managements for their help and encouragement. Special thanks to Rev. Dr. Antony Pushpa Ranjitham (Superior General), Rev. Sr. Thanaseeli Sengole (Asst. General), Rev.Sr.M. Margaret Inbaseeli (College Secretary), Rev. Dr. Pramila (Principal), Rev. Sr. Gnana Soundari(Provincial) and Mrs J.Antony Justina Mary (Vice Principal) for their Prayer and Blessings.

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