Extraction of Mangosteen Peel (Garcinia mangostana L.

as Corrosion Inhibitor for Carbon Steel

In Partial Fulfilment in Inquiries, Investigations and Immersion

Submitted to the Science Faculty of

Sen. Renato “Compañero” Cayetano Memorial Science

and Technology High School

Taguig City

By:

12 STEM HARIBON

Group 6

Corpuz, Jarod Abram Zak

Dalupang, John Benedict T.

Caranto, Marco Gabriel B.

Arbollente, Denmark D.

Naife, John Patrick V.

Palomo, Kizzle S.

JIMNAIRA U. ABANTO

Research Adviser

April 2025
 APPROVAL SHEET

This quantitative research entitled YOUR RESEARCH TITLE YOUR

RESEARCH TITLE HERE, prepared and submitted by LASTNAME,

Firstname MI., LASTNAME, Firstname MI., LASTNAME, Firstname MI.,

and LASTNAME, Firstname MI., in partial fulfillment of the requirements

for the Group No. of Grade and Section, has been examined and

recommended for acceptance and approval for oral examination.

JIMNAIRA U. ABANTO

Research Adviser

Approved by the panel of Examiners on Oral Examination

Accepted and approved in partially fulfillment of the requirements for the

Group No. of Grade and Section

Head Teacher III - Science

First and foremost, praises and thanks to the God, the Almighty, for

His showers of blessings throughout our research work to complete the

research.

We would like to express our deep and sincere gratitude to our

own ……

-Researchers
 ABSTRACT

A concise and factual abstract is required 250 words. The

abstract should state briefly the purpose of the research, the principal

results and major conclusions. It should be Italic.

Keywords: Provide 5 keywords or phrases in alphabetical order,

separated by commas.
 TABLE OF CONTENTS

I. Approval Sheet

II. Acknowledgement

III. Abstract

IV. List of Figures

V. List of Tables

VI. Chapter 1: The Problem and Its Background

1.1 Background of the study

1.2 Statement of the Problem

1.3 Hypotheses

1.4 Conceptual Framework

1.5 Significance of the study

1.6 Scope and Delimitation of the study

1.7 Definition of Terms

VII. Chapter 2: Review of Related Literature and Studies

2.1 …. (Give title based on your salient findings – thematic format)

VIII. Chapter 3: Research Methodology

3.1 Research Design

3.2 Research Population and Sample (for descriptive like behavioral

&RIM,SIE)
 3.2 Gathering of Materials (for Experimental, RIM and SIE)

3.3 Procedures (for Experimental, RIM and SIE)

3.4 Research Instruments

3.5 Validity and Reliability of Instruments

3.6 Research Intervention (if applicable)

3.7 Data Collection Procedure

3.8 Data Analysis

**you can also give title based on your process

IX. Chapter 4: Data Presentation, Analysis, and Interpretations

9.1 …. (Give title based on your presentation of data, analysis and

interpretation)

9.2 ….

9.3 …

9.4 …..

X. Chapter 5: Summary, Conclusions and Recommendations

5.1 Summary of findings

5.2 Conclusion

5.3 Recommendations

XI. References

XII. Appendices
 Appendix A: Letter of Informed Consent

Appendix B: Letter for Validation of Instrument

Appendix C: Survey Questionnaire

Appendix D: Certificate of Validation

Appendix E: Online Questionnaire (if Applicable)

Appendix F: Questionnaire Results / Consolidated results

Appendix G: Online Questionnaire Results (If applicable)

Appendix H: Document Analysis Results (if Applicable)

Appendix I: Plagiarism Checker

Appendix J: Grammar Checker

Appendix K: AI Checker

XIII. Curriculum Vitae

1.1 Conceptual Framework

1.2 Cvc

1.3 Kj

LIST OF TABLES

3.1 Demographic profile

3.2

1
 CHAPTER 1:

THE PROBLEM AND ITS BACKGROUND

1.1 Background of the Study

Carbon steel continued to pose one of the most vexing challenges in

various industries due to its wide application on the account of several

good mechanical properties, availability, and low cost. However, the

susceptibility of carbon steel to corrosion under different environmental

conditions has resulted in huge economic losses and security risks.

Corrosion inhibition means to suppress corrosion would include the use

of synthetic inhibitors, coatings, and cathodic protection. Corrosion

inhibitors are thought to favorably influence activities involved in the

corrosion process; particularly, they seem to be attractive for their high

work efficiency and simpler application. But essentially, most synthetic

inhibitors originate from toxic and non-biodegradable chemicals, which

may eventually pose a danger to both health and environment. (Shane.

2024).

Responding to the demand for more sustainable and natural choices,

research has begun to focus on the use of natural substance as corrosion

inhibitors. Plant extracts have emerged as a very promising class of green

inhibitors due to their availability, biocompatibility, and other bioactive

compounds such as alkaloids, flavonoids, tannins, and saponins. The

2
bioactive compounds, when adsorbed over metal surfaces, form protective

films against the electrochemical corrosion of alloys within the solution.

In the same vein, the mangosteen (Garcinia mangostana L.), dubbed the

"queen of fruits," is known for its nutritional and medicinal

properties.(Aronson et.al 2016). The peel of the mangosteen, often

considered as waste, possesses antibacterial and antioxidant properties,

xanthones, tannins, and flavonoids. Initial studies have indicated that

these compounds exhibit these were therefore potential corrosion

inhibitors. (Sheydaei et.al 2024).

The present study intends to explore the potential of mangosteen peel

extract to act as a green corrosion inhibitor for carbon steel. This research

aims to facilitate such advancement and contribute a little to the

development of sustainable and environmentally friendly solutions to

industry applications by investigating the chemical composition of the

extract and its corrosion inhibition performance. Furthermore, the use of

mangosteen peel adheres to waste valorization tenets; it further promoted

the circular economy by casting agricultural by-products as valuable

resources.

1.2 Statement of the Problem

The main goal of this study focuses on the effective use of the

properties of mangosteen peel for inhibiting corrosion.

Specifically, it answers the following questions:

3
 1. What is the resistance of mangosteen peel extract as a corrosion

inhibitor using Electrochemical Impedance Spectroscopy (EIS)?

2. Is there a significant difference in corrosion between treated and

untreated carbon steel?

3. Is there a way to prolong the life of mangosteen peel extracts?

1.3 Hypotheses

Based on the identified research questions, the researchers formulated

the following hypotheses”

�� = Garcinia mangostana L. peels extract does significantly provide an

obvious effectiveness in preventing carbon steel corrosion in an acid

solution compared to a control free of inhibitor

�� = Garcinia mangostana L. peels extract does not significantly provide

an obvious effectiveness in preventing carbon steel corrosion an acid

solution compared to a control free of inhibitor

1.4 Conceptual Framework

In this study, the independent variable will be the concentration of

the Mangosteen Peel Extract, as it is the chief factor expected to affect the

corrosion rate of the carbon steel. The concentration of the extract will be

varied to assess its effect on the rate of corrosion, under the assumption

that higher concentrations would reduce corrosion rate due to an

4
increased presence of active compounds in the extract. The corrosion rate

of the steel will, however, act as the dependent variable measured through

weight loss or any other appropriate procedure. Also, since the experiment

is in a home-made setup, it is not practical to measure environmental

factors such as humidity. The humidity may fluctuate in time, since the

experiment will really take place in one of the researcher’s house and

therefore it is, in other words, an uncontrolled environmental variable that

can affect the results.

Figure 1.1 Paradigm of the independent and dependent variables on Extraction of

Mangosteen Peel (Garcinia mangostana L.) as Corrosion Inhibitors for Carbon Steel

1.6 Significance of the study

The success of this study will be able to provide an alternative

corrosion inhibitor for carbon steel. The results of this study will have

significant implications for various sectors including:

Oil and Gas Industries. It is usually run in acidic conditions that

promote corrosion of steel. The use of a natural inhibitor for corrosion,

such as mangosteen peel extract, can reduce operating costs as well as

increase the lifetime of carbon steel infrastructure.

5
 Manufacturing and Construction. A low-cost and eco-friendly

method of corrosion prevention can benefit industries that make use of

carbon steel pipeline, manufacturing plant and construction.

Farmers and Agricultural Communities. The present study will be

able to provide new avenues of economic feasibility while making waste-

to-resource initiatives possible by giving a meaning to the otherwise

discarded mangosteen peels.

Organization of Waste Management. This current study aims to

reduce agro-wastes while at the same time translating these wastes to

something that can be used as an edible industrial commodity thus

promoting a more environmentally friendly approach towards handling

waves.

Students and Teachers. The topic is very relevant for green

chemistry and sustainable industrial process so it will be quite applicable

as a case study or reference in teaching chemistry courses, material

sciences, or environmental engineering

Future Researchers. The result will further the knowledge of the

naturally sourced corrosion inhibitor while motivating further studies on

other agricultural byproducts that may also possess the ability to prevent

corrosion.

6
1.7 Scope and Delimitation of the Study

This study aims to determine the efficacy of the mangosteen peel as a

bio-agent to prevent corrosive tendencies against steel. It includes the

analysis of the weight differences of the steel samples and the duration of

the entire experiment. Observational checklists and statistical treatments

are utilized to gather data. The variables considered are the corrosion rate

of the metal and the amount of peel extract used in the experiment.

The study is limited to using only 304 carbon steel without

considering other forms of steel alloys. It is also important to note that the

study is conducted in a tropical climate; results may vary in colder, less

humid climates where corrosion is subtly less significant. Furthermore, it

primarily utilizes a simple true experimental method to determine the

efficacy of mangosteen peel extract as a corrosion inhibitor for carbon

steel.

1.8 Definition of Terms

For the purpose of clarification the important terms used in the study

have been defined.

The following terms are:

Mangosteen. It refers to the tropical fruit with sweet juicy white

segments of flesh inside a thick reddish-brown rind.

7
Corrosion. It refers to the process of corroding metal, stone, or other

materials

Inhibitor. It refers to the substance which slows down or prevents a

particular chemical reaction or other process.

Antioxidant. It refers to the substance that inhibits oxidation,

especially one used to counteract the deterioration of stored food

products.

Resistance. It refers to the power that acts to impede or slow down

something’s action

Extract. It refers to the product carrying a substance’s active

component in a concentrated form.

Waste-to-Resource Initiative. It refers to the activity that involves

practising sustainability in converting waste materials into useful

products or resources while minimizing environmental impact.

Green Chemistry. It refers to the practice of designing products and

processes that are efficient in minimizing or eliminating the use and

generation of hazardous substances in their design, manufacture,

and application.

Agro Waste. This refers to the crop residues, parts of fruits and

vegetables, or other discarded agricultural materials that could be

utilized for industrial and environmental purposes.

Industrial processes of sustainability. This refers to the industrial

processes that protect the environment through the process of

8
 conserving natural resources, minimizing waste, and using

renewable materials.

CHAPTER 2:

REVIEW OF RELATED LITERATURE AND STUDIES

For further understanding of the study, this chapter presents the

review of related literature and studies which the researcher found

relevant to the present study. The researchers made use of different

essential reading materials to gather information and to broaden the

knowledge of the researchers such as books, thesis and other websites.

The information gathered by the researchers mainly focuses on the

Garcinia mangostana L. as a corrosion inhibotor for Carbon Steel

2.1 Plant Extracts as Corrosion Inhibitors in Acidic Solution

Plant extracts have emerged as effective green corrosion inhibitors,

offering environmental benefits alongside inhibition efficiency. For

instance, Thomas and their colleagues (2020) reported that the fruit rind

extract of Garcinia indica (GIW) achieved 93% inhibition efficiency in 0.5

M HCl and 87% in 1 M HCl at 303 K, with a slightly reduced efficiency of

80% in 1 M HCl at 333 K. Similarly, Prabhu and Rao (2013) demonstrated

that Garcinia indica extract acted as a mixed inhibitor for aluminum in

0.5 M phosphoric acid through chemical adsorption.

9
Holla (2024) highlighted the sustainable nature of plant-based inhibitors,

emphasizing their chemical diversity and synergistic effects, which

enhance corrosion protection. Kusumaningrum (2022) found that

Artocarpus heterophyllus peel extract served as a mixed-type inhibitor for

copper in nitric acid, adhering to the Frumkin adsorption isotherm.

Furthermore, Ngatin and Sihombing (2020) observed inhibition

efficiencies of 76.53% in 0.1 M HCl and 20.83% in 1 M HCl for

mangosteen peel extract, attributing the protection to the formation of

chemical covalent layers with ferro ions.

Popoola (2023) studied Cucumeropsis mannii shell extract and noted a

high inhibition efficiency of over 91% for carbon steel in NaCl solution.

The extract formed a protective monolayer, significantly increasing

polarization resistance. Rocha (2014) found that aqueous extracts of

mango and orange peels provided inhibition efficiencies of 97% and 95%,

respectively, for carbon steel in hydrochloric acid after 24 hours of

immersion at 400 mg/L, attributing the effectiveness to polar hetero sides

in the extracts.

Additionally, Risnawati (2022) reported that mangosteen peel extract

achieved a maximum inhibition efficiency of 76.68% at 500 ppm and 308

K, following the Freundlich isotherm adsorption model. Vinod (2016)

explored the pericarp extract of Garcinia mangostana and identified its

non-toxic, cost-effective corrosion inhibition properties for mild steel in

10
acidic mediums, with changes observed in the functional groups of the

extract. These findings collectively underscore the promise of plant-based

extracts as eco-friendly, efficient corrosion inhibitors across various

metals and corrosive environments.

2.2 Green Inhibitors and Mechanisms in Corrosion Control

Organic and natural inhibitors have gained significant attention for their

effectiveness in preventing corrosion, particularly in acidic environments.

Organic inhibitors, which rely on adsorption onto metal surfaces to form

protective layers, exhibit variable efficiency influenced by the type of

inhibitor, metal, and environmental factors. The mechanisms of these

inhibitors often involve interactions with active functional groups, as

revealed by adsorption isotherms and surface analysis techniques

(Devendra et al., 2024). Green corrosion inhibitors derived from plant

extracts, such as cucumber leaf extract, have shown promising results as

mixed-type inhibitors. These inhibitors form a geometric protective layer

on metal surfaces, suppressing corrosion by limiting the exposure of the

metal to aggressive substances (Feng et al., 2022). Similarly, jackfruit peel

extract has been highlighted for its environmentally friendly corrosion

inhibition capabilities, achieving 90.98% efficiency at 1000 ppm in a 1 M

HCl solution through potentiodynamic polarization methods

(Kusumaningrum et al., 2022).

11
Natural gums also hold potential as corrosion inhibitors in harsh

environments, such as NaCl and CO2-rich conditions common in the oil

and gas industry, underscoring their dual benefits of corrosion protection

and environmental safety (Kumar et al., 2022). Additionally, water-soluble

ions, such as chloride and sulfate, contribute significantly to corrosion

processes in reinforced concrete, emphasizing the complexity of corrosion

and the need for multi-faceted mitigation strategies (Khaloo et al., 2024).

Studies on plant-based inhibitors, such as Garcinia gummi-gutta leaf

extract, have shown that bio-synthesized silver nanoparticles generated

from these extracts effectively inhibit both cathodic and anodic processes

on mild steel, forming robust protective barriers and preserving surface

integrity (Shamnamol et al., 2023).

Extracts from carrot peels and coconut coir have also demonstrated

substantial corrosion inhibition efficiencies. Carrot peel extract, for

instance, achieved a threefold reduction in corrosion rates for mild steel in

a 1 M HCl solution by adsorbing onto the metal surface (Saeed et al.,

2020). Similarly, tannin extraction from coconut coir optimized using

response surface methodology revealed the role of condensed tannins in

corrosion inhibition, with water proving to be the optimal solvent for

extraction (Sirisangsawang & Phetyim, 2023). Furthermore, combining

turmeric and purple sweet potato extracts has proven effective as a green

inhibitor for API-5L in a 3.5% NaCl environment, with key compounds

12
such as curcumin, kaempferol, and anthocyanin contributing to the high

inhibition efficiencies observed (Wijaya et al., 2023).

Overall, these studies emphasize the growing importance of natural and

plant-based corrosion inhibitors, not only for their effectiveness but also

for their environmental benefits, offering sustainable solutions for

mitigating corrosion across various industrial applications.

2.3 Nanomaterial Enhanced Inhibition and Surface Coatings

Green nanomaterials have emerged as a cornerstone in modern corrosion

protection strategies due to their eco-friendly synthesis and remarkable

efficiency. Recent advancements have showcased the potential of these

materials in mitigating corrosion while aligning with sustainability goals.

For instance, silver nanoparticles synthesized using cashew leaf extracts

demonstrated superior inhibition efficiency, showcasing the role of plant-

based synthesis in developing cost-effective solutions (Elangovan &

Srinivasan, 2023). Manganese oxide (MnO) nanoparticles produced via

environmentally friendly methods further highlight the significance of

green approaches in corrosion inhibition (Pereira et al., 2024). Smart

nano-based coatings have been identified as adaptable solutions that

enhance corrosion resistance by responding dynamically to environmental

conditions (Lee et al., 2023).

Furthermore, plant-derived nanomaterials have gained attention for their

dual benefits of corrosion protection and environmental compatibility. For

materials not only inhibit corrosion effectively but also minimize ecological

impact, making them ideal for industrial applications (Sharma et al.,

2022). Research combining natural extracts, such as purple sweet potato

and turmeric, with nanomaterials has demonstrated synergistic effects,

enhancing performance even in aggressive environments (Wijaya et al.,

2023). The efficacy of nanotechnology-based coatings in providing

protection against corrosion in harsh conditions has been extensively

documented, indicating their transformative potential in modern

industries (Singh et al., 2024; Wang et al., 2023). Reviews of nanoparticle-

based corrosion inhibitors consistently emphasize their ability to reduce

environmental impact while maintaining high performance (Ali et al., 2022;

Kumar et al., 2023; Rajasekaran et al., 2022). Surface treatments using

green nanomaterials, such as those derived from natural sources, further

underline their importance in achieving sustainable corrosion mitigation

(Zheng & Zhang, 2023).

14
 CHAPTER 3:

RESEARCH METHODOLOGY

3.1 Research Design

In this study, a Simple True Experimental Research Design was

applied to rigorously assess the effectiveness of mangosteen peel extract

as a corrosion inhibitor for carbon steel. This design involved creating two

groups—one treated with mangosteen peel extract and one untreated

(control group)—to measure and compare corrosion levels. By applying

this structured approach, the study produced reliable, unbiased results

on the extract's potential for corrosion inhibition, as well as insights into

its suitability as an environmentally friendly alternative to synthetic

corrosion inhibitors.

Table 3.1: Simple True Design

Before After

Weight (kg) Weight (kg)

Trial 1 Trial 2 Trial 3 Trial 1 Trial 2 Trial 3

Control Group

Untreated

15
 Treated

3.2 Gathering Materials

The gathering of materials was a critical phase in this research, as it

ensured the availability and quality of all resources needed for accurate

experimentation and analysis. This section outlined the specific materials

required, their sources, and the preparatory steps taken to standardize

and prepare them for use in the study. By meticulously selecting and

documenting each material, the study aimed to ensure consistency across

all experimental trials, thereby enhancing the reliability and

reproducibility of the findings.

Table 3.2: Materials Needed

Materials Quantity

Mangosteen 1 kilo

Acetic Acid 500 mL- 1L

WD-40 100 mL

304 Carbon Steel 6 plates

pH Strips 3-5 strips

16
Equipment

In this study, a range of specialized tools and apparatus were utilized

following the initial gathering of materials to effectively process the by-

product of mangosteen peel. Each piece of equipment was selected to

ensure precision and efficiency in handling, extracting, and analyzing the

properties of the mangosteen peel. This section detailed the essential

equipment required for the study, including devices for extraction,

processing, and measurement, as well as supplementary apparatus

essential for maintaining controlled experimental conditions

Table 3.3. Equipment needed

Equipment Quantity

Grinder/ Blender/ Mortar and 1 unit

Pestle

Water Bottle 1 pc

Colander 1

Bowls 2-4

Oven 1

17
3.2 Research Population and Sample

The experiment in this study consists of carbon steel samples,

which are commonly used in various industrial applications. These

samples were chosen due to their susceptibility to corrosion, making them

ideal subjects for testing corrosion inhibitors. The researchers selected a

total of 6 carbon steel samples to serve as the study's sample size. The

samples were divided into two groups: the control group, which was left

untreated, and the experimental group, which was treated with

Mangosteen Peel Extract. Both groups were exposed to similar

environmental conditions to ensure consistency. The sample size was

determined based on the research objectives and the need to obtain

reliable data for statistical analysis. The chosen samples were

representative of carbon steel typically used in practical applications,

ensuring that the results would be relevant to real-world scenarios

3.3 Procedures

The procedures elaborated step-by-step how to assess the effectiveness

of mangosteen peel extract as a corrosion inhibitor on carbon steel, from

peel preparation and extraction to immersion testing and measurement of

the corrosion rate. The procedures were as follows:

18
 Figure 3.2: Flow of Procedures

1. Preparation of Mangosteen Peel

Fresh mangosteen peels were collected, cleansed thoroughly under

running water to remove dirt and debris, and then sun-dried or

oven-dried to eliminate moisture content.

2. Grinding and Powdering

The dried peels were ground into a very fine powder to increase the

surface area and facilitate efficient extraction of active compounds.

3. Solvent Extraction

A suitable solvent, such as ethanol or methanol, was used to extract

the active compounds from the powdered peel through Soxhlet

extraction and maceration processes.

4. Filtration

The extract solution was filtered to remove solid residues, producing

a clear solution containing the extracted compounds.

5. Concentration of Extract

19
The solvent was evaporated using a rotary evaporator or another

concentration method to obtain a concentrated form of the

mangosteen peel extract.

6. Preparation of Corrosion Test Solution

An acidic solution, such as HCl, was prepared to act as the

corrosion medium for testing the carbon steel samples.

7. Preparation of Extract Concentrations

The mangosteen peel extract was diluted to create various

concentrations for testing different inhibition levels.

8. Immersion Test on Carbon Steel Samples

Carbon steel samples were immersed in the acidic solution, with

different concentrations of mangosteen peel extract added for each

immersion. The samples were left in the solution for a specified

duration.

9. Data on the Corrosion Rate

The corrosion rate for each sample was measured and recorded

using weight loss or electrochemical techniques. This data was

analyzed to determine the effectiveness of the mangosteen peel

extract as a corrosion inhibitor.

20
3.4 Research Instruments

The instrument applied in this study is the observational checklist,

which is designed to systematically assess and document the corrosion

inhibiting effectiveness of Mangosteen (Garcinia mangostana L.) Peel

Extract on carbon steel. This checklist is developed to identify and

evaluate key indicators of corrosion, such as surface discoloration, pitting

formation, rust intensity, weight loss, and changes in surface morphology

over a specified period.

Table 3.4.1: EIS ANALYSIS

Treatment Trial Impedance Impedance Phase Corrosion Comments

No. (Z) Before (Z) After Angle Inhibition

Exposure Exposure Shift Efficiency

(Ohms) (Ohms) (%)

Positive Control Trial

(No Inhibitor) 1

Trial

Negative Trial

21
Control 1

(Commercial

Inhibitor)

Trial

Experimental: Trial

Mangosteen 1

Extract 25%

Trial

Experimental: Trial

Mangosteen 1

Extract 50%

Trial

Experimental: Trial

Mangosteen 1

Extract 100%

Trial

22
TABLE 3.4.2: Gravimetric Analysis

Treatment Trial Initial Final Weight Corrosion Inhibition Comments

No. Metal Metal Loss Rate Efficiency

Weight Weight (g) (mm/y) (%)

(g) (g)

Positive Trial

Control (No 1

Inhibitor)

Trial

Negative Trial

Control 1

(Commercial

Inhibitor)

Trial

Experimental: Trial

23
Mangosteen 1

Extract 25%

Trial

Experimental: Trial

Mangosteen 1

Extract 50%

Trial

Experimental: Trial

Mangosteen 1

Extract 100%

Trial

3.5 Validity and Reliability of Instruments

To endure the validity and reliability of instruments, the researchers

sought the expertise of professionals knowledgeable in the field of

corrosion inhibition and material design. These experts were consulted to

assess the experimental design, methodology, and overall feasibility of the

24
study.

To help in the validation process, the researchers distributed booklets

with thorough explanations of the experiment, including the materials

used, procedures, and expected results. Experts were asked to examine

these documents and provide feedback and recommendations to improve

the study's accuracy and efficacy.

One of the experts' primary recommendations was that the trial be run

for at least 20 days to ensure a fair comparison with a known

competitor—mango peel extract—as an anti-corrosion inhibitor, which

has been shown to maintain its effectiveness for the same time. The

experts also proposed improving measurement procedures, standardizing

ambient conditions, and conducting several experiments to increase the

trustworthiness of the findings.

3.6 Data Collection Procedure

Below is the procedure done by the researchers before, during, and after

data gathering.

Pre-Data Gathering

The researchers carried out thorough preparations to ensure the

reliability and accuracy of their study. They conducted an extensive

review of related literature to understand previous research on corrosion

25
inhibitors, particularly those derived from natural sources like

Mangosteen Peel. After analyzing the problem, they decided to explore the

effectiveness of Mangosteen Peel Extract as a corrosion inhibitor for

carbon steel. They assessed the significance of the study and determined

the appropriate research design. The necessary materials for the

experiment were also identified. To ensure the reliability of the research

instrument, they developed an observational checklist to systematically

record changes on the carbon steel surface. The checklist was reviewed

and revised to ensure it effectively measured the intended variables.

Data Gathering

The data gathering process involved the systematic collection of relevant

data to assess the effectiveness of Mangosteen Peel Extract as a corrosion

inhibitor for carbon steel. The researchers first prepared the carbon steel

samples and applied the Mangosteen Peel Extract solution to the

designated samples, while others were left untreated to serve as control

groups. The samples were then immersed in a corrosion-promoting

environment, which was carefully monitored for environmental factors like

temperature and humidity. Over a specified period, the researchers

regularly observed the samples, documenting changes in the surface

conditions such as rust formation, discoloration, and pitting using the

26
observational checklist. Additional measurements, including weight loss

and electrochemical analysis, were taken to quantify the degree of

corrosion. The data gathered were recorded systematically and analyzed to

determine the corrosion-inhibiting effects of Mangosteen Peel Extract. The

findings were then compared to the untreated samples to evaluate the

overall efficacy of the extract in reducing corrosion on carbon steel

Post-Data Gathering

Afterward, the researchers analyze and interpret the data they gathered.

They organize the data based on observations such as changes in surface

conditions, weight loss, and results from electrochemical analysis. Then,

they compare the treated samples with the untreated control samples to

determine the effectiveness of Mangosteen Peel Extract as a corrosion

21inhibitor. The researchers summarize the data to conclude their study,

highlighting the degree of corrosion prevention observed in the treated

samples. The researchers formulate recommendations based on the

findings, suggesting possible improvements or further studies. Lastly, the

researchers propose the output of their study regarding the effectiveness

of Mangosteen Peel Extract in reducing corrosion on carbon steel and its

potential application as an eco-friendly corrosion inhibitor.

27
3.7 Data Analysis Research

To analyze the effectiveness of mangosteen peel (Garcinia mangostana

L.) extract as a corrosion inhibitor for carbon steel in an acetic acid

solution, both corrosion rate and inhibition efficiency were essential

metrics.

For a better understanding of the study, a statistical tool was used

to answer the specific problem of the study. The formula is clearly

illustrated and explained.

A. Corrosion Rate

This was used to determine the weight loss of carbon steel samples

exposed to the acetic acid solution, both with and without the extract.

Using the formula for corrosion rate, a quantifiable measure was obtained

to indicate how quickly the metal corroded under the test conditions.

Where: ΔW = Weight loss of the metal sample, A = Surface area of

the sample, and T = Exposure time

28
B. Inhibition Efficiency

This was used to determine the percentage reduction in corrosion

rate due to the presence of the mangosteen peel extract. By comparing the

corrosion rates with and without the extract, and calculating the

inhibition efficiency, the study gauged how effectively the extract

mitigated corrosion. The inhibition efficiency was calculated using the

formula:

Where: (CR)0 = Corrosion rate without the inhibitor, and (CR)I =

Corrosion rate with the inhibitor

A higher inhibition efficiency indicated that the extract was effective

in reducing corrosion, providing a clear measure of its performance as a

corrosion inhibitor in acetic acid solution.

29
 CHAPTER 4:

DATA PRESENTATION, ANALYSIS AND INTERPRETATION

This chapter presents the results and analysis of the data gathered from

the experiments conducted on steel treatment and its corrosion rate.

Observations and results are recorded in an interval of two days while the

carbon steel samplesremain submerged in an acidic solution. Three

batches of carbon steel samples are to be observed undedifferent

conditions: one treated with Mangosteen peel extract, another treated with

a commercial corrosion inhibitor (WD40), and a control group left

untreated.

4.1 Results of steel treated with the Mangosteen Extract

Based on the data, the carbon steel samples treated with mangosteen

peel extract exhibited gradual corrosion over the 20-day experiment. The

initial weight of the nails was approximately 10 grams, and measurements

were taken at two-day intervals to determine mass loss due to corrosion.

In the early stages, weight loss was minimal, with only 0.002 grams lost

by day 2 and 0.007 grams by day 4. However, by day 6, a more noticeable

decline occurred, with the sample losing 0.119 grams. The corrosion rate

then fluctuated, with smaller losses recorded on day 8 (0.016 grams) and

day 10 (0.057 grams). By the middle of the experiment, the mass loss

varied slightly, with 0.037 grams lost by day 12 and 0.021 grams by day

14. Although the decline slowed at times, the samples continued to

30
degrade, losing 0.047 grams on day 16 and 0.013 grams on day 18. By

the end of the experiment, the total recorded mass loss was 0.423 grams

(or 423 milligrams).

Steel samples treated with Mangosteen extract had apparent changes

during the study. The main observations were a major decline in rust

development

compared to the untreated steel. The bioactive compounds found in

Mangosteen extract, and more specifically its antioxidant component,

seemed to be responsible for corrosion inhibition. A thin protective coating

was seen developing on the steel surface, indicating possible barrier

action against moisture and environmental substances. Though the

Mangosteen-treated steel was found to offer some level of protection, it

was still not totally resistant to oxidation since minute discoloration and

very small pitting were still apparent in some spots.

Table 4.1: Result of Steel Treated with Mangosteen Extract

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 4.2 Results of steel treated with WD40

The carbon steel samples treated with WD-40 experienced minimal

corrosion. In the early days, weight loss was almost negligible, with only

0.003 grams lost by day 2. This trend continued, with slight variations

such as a 0.001-gram loss by day 6 and no measurable change on days 8

and 18. Some fluctuations, including occasional negative values, were

likely due to instrument sensitivity rather than actual mass gain. Despite

these minor inconsistencies, the overall corrosion rate remained extremely

low, with a total recorded mass loss of just 0.009 grams (9 milligrams) by

the end of the experiment, suggesting that WD-40 effectively inhibited

corrosion.

The WD-40-treated steel samples showed excellent corrosion protection.

In contrast to the Mangosteen extract, WD-40 created an instant

hydrophobic coating on the steel surface, which repelled water and greatly

inhibited rust formation. Throughout the study period, the WD-40-treated

steel retained its initial appearance with very little evidence of oxidation.

The presence of petroleum-based ingredients in WD-40 was responsible

for its sustained protective action. Although WD-40 was effective in rust

prevention, it did not make the steel physically more resilient to

degradation. Its function was confined to corrosion

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 protection but not to structural reinforcement. The tests proved that

WD-40 is an effective short-term rust preventer but that, in the long term,

further protective coatings may be necessary.

Table 4.2: Result of treated steel with WD40

DAY WD40 (g) MASS LOSS (g)

2 9.997 0.003

4 9.994 0.003

6 9.993 0.001

8 9.992 0

10 9.993 0.001

12 9.992 -0.001

14 9.993 -0.001

16 9.994 0.002

18 9.992 0

20 9.992 0.001

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4.3 Results of the untreated steel

The untreated carbon steel samples corroded at a significantly

higher rate compared to the treated groups. By day 2, they had already

lost 0.02 grams, and the degradation continued steadily, with 0.099

grams lost by day 6. By day 12, the samples had shed another 0.075

grams, and by day 16, they had lost 0.061 grams more. Although there

were minor fluctuations, the overall trend showed continuous material

loss over time. By the final day of the experiment, the total mass loss had

reached 0.544 grams (544 milligrams), demonstrating that the absence of

a protective coating left the steel highly vulnerable to corrosion.

The untreated steel specimens showed the most prominent evidence

of corrosion. During the course of the research, rust formation was

evident to the naked eye, and with time, the rust intensified, spreading

over the surface. The absence of any protective coating made the steel

extremely vulnerable to oxidation as a result of exposure to air and water.

Table 4.3: Untreated steel result

DAY NAKED (g) MASS LOSS (g)

2 10.01 -0.01

4 9.99 0.02

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6 9.891 0.099

8 9.825 0.066

10 9.761 0.064

12 9.686 0.075

14 9.615 0.071

16 9.554 0.061

18 9.511 0.043

20 9.456 0.055

4.4 Comparative Analysis of Results

A comparative analysis of the three sample groups demonstrated

the varying degrees of protection offered by different treatments. The table

below summarizes the key findings:

Table 4.4: Comparison Among Different Treatment Method

Treatment Rust Surface Protective

Method Formation Integrity Effectiveness

Mangosteen Minimal Slight Moderate

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 Extract Alteration

WD-40 Negligible No Visible High

Change

Untreated Steel Significant Degraded None

From the table, it is evident that WD-40 provided the highest level

of protection, significantly reducing rust formation. The Mangosteen

extract also demonstrated potential as a natural corrosion inhibitor,

though not as effective as WD-40. The untreated steel, as expected,

suffered the most degradation.

36
 CHAPTER 5:

SUMMARY, CONCLUSION AND RECOMMENDATIONS

This study looked into the possibilities of mangosteen peel extracts as

natural corrosion inhibitors for carbon steel. The findings, showing

modest but encouraging levels of inhibition, underline the need for

additional research to maximize the efficiency of the extract. This chapter

delves into the findings in depth, analyzing the effects and identifying

various possibilities for future studies to improve the effectiveness of

mangosteen peel extract as bio-based inhibitors.

5.1 Summary of findings:

This research studied the possibility of mangosteen peel extract as a natural, eco-

friendly corrosion inhibitor for carbon steel. The study employed electrochemical

impedance spectroscopy to assess the extract's efficacy at various doses and exposure

times. While the study found that mangosteen peel extract had some corrosion inhibition

characteristics, the effect was considered mild. The extract reduced the corrosion rate,

however the steel still showed minor symptoms of oxidation. More study is needed to

further develop the extraction process, experiment with other portions and formulations,

and investigate the fundamental mechanisms of inhibition. The data indicate that

mangosteen peel extract, while not a highly efficient inhibitor, could be utilized as a

supplement to conventional corrosion protection strategies.

37
 Important factors to highlight:

1. Mild but Significant: Although the effects were mild, there were still

observations that the corrosion of the carbon steel was reduced; thus,

with further improvements, the mangosteen can be a sustainable

substitute for corrosion inhibition.

2.Sustainability:Mangosteen peel as a corrosion inhibitor is a

sustainable option for a variety of reasons. First, it makes use of a widely

available and frequently wasted byproduct of the fruit industry,

decreasing waste and boosting resource efficiency. Second, mangosteen

peel extract is biodegradable, which means it degrades naturally in the

environment, reducing pollution. Its lower toxicity than conventional

inhibitors makes it safer for both people and the environment.

Furthermore, using locally grown agricultural goods such as mangosteen

can help local economies and support sustainable agricultural practices.

In short, mangosteen peel is a potential and sustainable alternative to

standard corrosion inhibitors that supports environmental conservation

and economic development goals.

3.Future Direction: Investigating corrosion inhibition processes may

lead to a better understanding and potential performance improvements.

Field testing in real-world settings would validate laboratory findings and

38
assess their practicality for industrial applications. These guidelines not

only aim to improve the effectiveness and application of mangosteen peel,

but they also reflect the increasing focus on sustainability and eco-

friendliness in industrial processes.

5.2 Conclusion

Caranto’s part

5.3 Recommendations

With the results of the study, it is recommended to further explore the

possibilities of mangosteen peel extracts as an eco-friendly substitute for

corrosion inhibition. The following are steps in order to further to improve

the effects of the application of mangosteen as a corrosion inhibitor:

1. Invest in high quality equipment and materials. The use of better

equipment and materials in research will lead to more concise results. It

will also help with the experiment providing a more desirable result.

2. Implement strict quality control. For a more precise result, the

researchers must perform regular inspections on the experiment.

Regularly inspecting the experiment will also help track the status of the

variables and efficiently document the changes.

39
 3. Document. Detailed documentation of the research process will help

ensure a better flow in the experimentation. Documenting will help track

the adjustment that is most effective in providing the desired result.

4. Conduct pilot studies. The researchers should test different

methodologies before implementing them into the research in order to

make necessary adjustments to get better results.

The aforementioned are recommendations in order to improve the

results of the research and observe the effectiveness of mangosteen as an

eco-friendly corrosion inhibitor.

40
 REFERENCES

APPENDICES

Appendix A: Letter of Informed Consent

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CURRICULUM VITAE

42