KOVALEN: Jurnal Riset Kimia, 12.
, 2026: 44-52 https://bestjournal.
id/index.
php/kovalen Photodegradation of Crystal Violet Dyes Using Fe2O3/CuO with the Addition of MEA Additive Alya RamadhaniA.
Hary Sanjaya.
Edi Nasra.
Fitri Amelia Padang State University.
Jl.
Prof.
Dr.
Hamka.
Kampus Air Tawar.
Padang.
Sumatra Barat Abstract.
Synthetic dyes, including Crystal Violet (CV), are widely used in the textile and chemical industries and are increasingly released into the environment due to their toxic, mutagenic, and non-biodegradable nature.
The purpose of this work is to examine the photocatalytic degradation of CV utilising Fe2O3/CuO heterojunction with monoethanolamine (MEA) as an additive.
To maximise its optical and catalytic capabilities, the Fe2O3/CuO photocatalyst was synthesised using different CuO compositions and MEA volumes.
Using UV-Visible Diffuse Reflectance Spectroscopy (UV-DRS) and the Kubelka-Munk technique, the band gap energy was determined.
According to the findings, the incorporation of CuO did not show a pronounced effect, but it may contribute to the photocatalytic system through interfacial interactions and improved charge transfer within the FeCCOCE/CuO structure.
The lowest band gap value and optimal composition were found at 20% CuO, which was further reduced by adding 2 mL MEA.
Tests of photocatalytic activity were conducted for 120 minutes when exposed to UV and sunshine.
The results showed that CV had a high deterioration efficiency, reaching about 53.
87% when exposed to sunshine.
The creation of a Fe2O3/CuO heterojunction, which enhances charge separation and decreases electron-hole recombination, is responsible for the improved performance, whereas MEA enhances particle distribution and increases surface area.
These results suggest that FeCCOCE/CuO with MEA is a promising, economical, and ecofriendly photocatalyst for the treatment of wastewater contaminated with dyes.
Keywords: photocatalysis.
FeCCOCE/CuO, monoethanolamine.
Crystal Violet, band gap, wastewater treatment Abstrak.
Zat warna sintetis, termasuk Kristal Violet (CV), banyak digunakan dalam industri tekstil dan kimia dan semakin banyak dilepaskan ke lingkungan karena sifatnya yang beracun, mutagenik, dan tidak dapat terurai secara Tujuan dari penelitian ini adalah untuk menguji degradasi fotokatalitik CV menggunakan heterojunction Fe2O3/CuO dengan monoetanolamina (MEA) sebagai aditif.
Untuk memaksimalkan kemampuan optik dan katalitiknya, fotokatalis Fe2O3/CuO disintesis menggunakan komposisi CuO dan volume MEA yang berbeda.
Dengan menggunakan UV-Visible Diffuse Reflectance Spectroscopy (UV-DRS) dan teknik Kubelka-Munk, energi celah pita ditentukan.
Berdasarkan temuan tersebut, penambahan CuO tidak menunjukkan efek yang signifikan, tetapi dapat berkontribusi pada sistem fotokatalitik melalui interaksi antarmuka dan peningkatan transfer muatan dalam struktur FeCCOCE/CuO.
Nilai celah pita terendah dan komposisi optimal ditemukan pada 20% CuO, yang selanjutnya dikurangi dengan menambahkan 2 mL MEA.
Uji aktivitas fotokatalitik dilakukan selama 120 menit saat terpapar sinar UV dan sinar matahari.
Hasil penelitian menunjukkan bahwa CV memiliki efisiensi degradasi yang tinggi, mencapai sekitar 53,87% ketika terpapar sinar matahari.
Pembentukan heterojunction Fe2O3/CuO, yang meningkatkan pemisahan muatan dan mengurangi rekombinasi elektron-lubang, bertanggung jawab atas peningkatan kinerja, sedangkan MEA meningkatkan distribusi partikel dan meningkatkan luas permukaan.
Hasil ini menunjukkan bahwa FeCCOCE/CuO dengan MEA merupakan fotokatalis yang menjanjikan, ekonomis, dan ramah lingkungan untuk pengolahan air limbah yang terkontaminasi zat warna.
Kata kunci: fotokatalisis.
FeCCOCE/CuO, monoethanolamin (MEA).
Crystal Violet, energi celah pita, pengolahan limbah Received: April 6, 2026.
Accepted: April 30, 2026 Citation: Ramadhani.
Sanjaya.
Nasra.
, and Amelia.
Photodegradation of Crystal Violet Dyes Using Fe2O3/CuO With the Addition of MEA Additive.
KOVALEN: Jurnal Riset Kimia, 12.
: 44-52
Corresponding author E-mail aleazavanya@unp.
https://doi.
org/10.
22487/kovalen.
2477-5398/ A 2026 Ramadhani.
, et al.
This is an open-access article under the CC BY-SA license.
KOVALEN: Jurnal Riset Kimia, 12.
, 2026: 44-52 Ramadhani.
, et al
INTRODUCTION
the dyeing process and dumped into water The textile, printing, paper, and medical bodies, causing ecological imbalance and industries all employ Crystal Violet (CV), a environmental damage.
CV contamination can cationic dye that is a member of the triphenylmethane dye group.
This molecule is photosynthesise, decrease light penetration in difficult to break down naturally due to its water, and encourage the bioaccumulation of complex aromatic structure with dimethylamino hazardous substances in the food chain (Sen et groups, which contribute to its great chemical stability and photostability (Mancuso et al.
environmental impact of Crystal Violet requires The CV structure's large A-conjugated the development of efficient and eco-friendly system allows visible light at wavelengths treatment techniques to break it down into approximately 588Ae590 nm to be absorbed simpler and less dangerous molecules.
through AIeA* electronic transitions, giving it its Therefore.
As an n-type semiconductor with a small The band gap of around 1.
9Ae2.
2 eV, iron oxide (FeCCOCE) can absorb visible light efficiently and remarkable optical characteristics but also is widely investigated as a photocatalyst among function as electron donors that affect the metal oxides.
The most thermodynamically HOMOAeLUMO orbital energy and reduce the stable of its polymorphs is haematite (-FeCCOCE), molecular band gap.
Because of its persistent which is frequently employed in composite aromatic composition.
CV is resistant to materials to improve photocatalytic efficiency.
traditional wastewater treatment methods and Fe2O3 is a potential material for environmental tends to endure in the environment.
(Figure applications since it is readily available, inexpensive, environmentally friendly, and has good chemical stability.
Despite Fe2O3's photocatalytic efficacy is frequently constrained by quick electron-hole recombination and low charge carrier mobility, which lowers its catalytic efficiency.
Fe2O3 is often mixed with other semiconductors to create heterojunction structures that enhance charge separation and Figure 1.
Chemical structure of Crystal Violet (Cheruiyot et al.
, 2.
Because CV is toxic, non-biodegradable, and possibly mutagenic and carcinogenic to living things, its presence in aquatic settings has raised significant environmental concerns (Ahamad Nasar, 2.
According to allow interfacial charge transfer in order to get around these restrictions.
In order to increase photocatalytic activity and expand the possible use of Fe2O3-based materials in the breakdown of organic contaminants in wastewater, these approaches have been extensively investigated (Zhang et al.
, 2.
(Shamsudin et al.
, 2.
, an estimated 10Ae20% of the world's total CV output is wasted during KOVALEN: Jurnal Riset Kimia, 12.
, 2026: 44-52 Ramadhani.
, et al The inorganic compound copper(II) oxide Through electron-donor (CuO), also referred to as cupric oxide, has between its N and O atoms and metal centers, garnered a lot of interest in photocatalytic MEA can change the electrical characteristics applications because of its semiconductor of oxide material surfaces, improving particle CuO is a p-type semiconductor dispersion and charge transfer efficiency.
Additionally, polar-bound amine groups can be formed by MEA binding to oxide surfaces, effective absorption of visible light due to its increasing the surface's attraction for specific comparatively narrow band gap of about 1.
2 eV organic molecules or metal ions.
According to (Brasil, 2.
Because of their similar electrical quantum chemistry.
MEA has a high electron structures and charge carrier properties.
CuO density on nitrogen atoms ( = 1.
10 D, iE HOMO-LUMO = 4.
20 eV), which makes it an efficient electron donor when coordination electrical conductivity and redox behaviour, complexes with metal cations are formed.
while Fe2O3 is an n-type semiconductor with Because of these properties.
MEA can be used strong oxidation capabilities and high chemical as an organic dopant or structural modification stability (Marquez et al.
, 2.
When these two to stabilise the catalytic surface and affect local semiconductors are integrated, they create a charge distribution (Matyakubova et al.
, 2.
Fe2O3 CuO heterojunction interface that produces an photogenerated electronAehole pair separation and inhibits charge recombination (Belew & MATERIAL AND METHODS Materials All chemicals used in this study were of analytical grade and used without further Assege, 2.
CuO improves photon-to-chemical energy Iron.
conversion efficiency by enhancing visible light (FeClCEA6HCCO.
Ou99%) and copper(II) chloride absorption, which FeCCOCE alone is less capable dihydrate (CuClCCA2HCCO.
Ou99%) were purchased of utilizing.
Energy band theory states that from Merck (German.
Methanol .
Ou99.
CuO's lower conduction band level than Fe2O3 was obtained from Merck.
Monoethanolamine allows electrons to go from Fe2O3 to CuO while (MEA.
Ou99%) was supplied by Sigma-Aldrich.
holes stay in Fe2O3.
This leads to efficient Crystal Violet dye (C.
was also charge separation and increased photocatalytic activity (Akinnawo, 2.
The CuAA/CuA redox .
istilled wate.
was used as the solvent throughout the experiment.
CuO performance and interfacial electron transfer, indicating that the FeCCOCE/CuO heterostructure Aquadest Instrumentation The equipment used in this research included common laboratory glassware such as photodegradation in terms of stability, charge beakers, measuring cylinders, evaporating dishes, watch glasses, volumetric pipettes, a Sigma-Aldrich.
visible-light mortar and pestle, and a desiccator.
The synthesis process was assisted using a KOVALEN: Jurnal Riset Kimia, 12.
, 2026: 44-52 Ramadhani.
, et al magnetic stirrer (Model C-MAG HS 7.
IKA, precursor at a concentration of 0.
5 M and German.
with a stirrer bar, and a furnace CuClCCA2HCCO precursor at concentrations of 5%, (Type 10%, 15%, 20%, and 25%.
The mixture was Nabertherm
L3/11,
Nabertherm.
German.
for calcination.
then homogenized for approximately 1 hour The optical properties of the samples were and 30 minutes using a magnetic stirrer.
analyzed using a UV-Visible spectrophotometer Afterward, the solution was sonicated for 30 (Shimadzu UV-1800.
Shimadzu.
Japa.
The minutes at 45 W to create a homogeneous band gap energy was determined using a UV- solution .
, which was then allowed to Visible Diffuse Reflectance Spectrophotometer stabilize for a 24-hour period.
Additionally, the (UV-Vis DRS.
Shimadzu UV-2.
Crystal samples were dried for approximately one hour at 110 AC in an oven.
To obtain Fe/CuO, the gel characterized using X-Ray Diffraction (XRD, was calcined in a furnace for approximately PANalytical XAoPert PRO.
Malvern Panalytical, three hours at 400 AC.
To characterize the Netherland.
samples, they were stored in a desiccator and performed using Scanning Electron Microscopy then ground with a mortar and pestle after (SEM.
JEOL JSM-6510LV.
JEOL.
Japa.
The Morphological photocatalytic activity test was carried out under UV irradiation using a UV lamp (Philips UV Lamp.
Philips.
Netherland.
Synthesis of FeCCOCE/CuO material with the addition of MEA The CuClCCA2HCCO precursor was dissolved Procedure at various concentrations, namely 5%, 10%.
Synthesis of FeCCOCE material 15%, 20%, and 25%, while the FeClCEA6HCCO 50 mL of methanol, covered with plastic wrap, was used to dissolve the FeClCEA6HCCO precursor at a concentration of 0.
5 M.
The mixture was then homogenized for 40 minutes using a magnetic stirrer.
After that, the solution was sonicated for 30 minutes at 45 W to produce a homogeneous solution .
, which was then allowed to stabilize for a period of 24 Additionally, the sample was dried for approximately one hour at 110 AC in an oven.
To extract the Fe, the resulting gel was calcined precursor was dissolved at a concentration of 5 M.
The solutions were dissolved in 50 mL of methanol, then tightly covered with plastic wrap to prevent evaporation.
For forty minutes, a magnetic stirrer was used to homogenize the Next, 1 mL, 2 mL, and 3 mL of analytical-grade (MEA) were added to each solution, and the mixture was stirred again for approximately 1.
5 hours.
To ensure the homogeneity of the sol, the solution was sonicated for 30 minutes at 45 W.
in a furnace for approximately three hours at Photocatalytic activity of CuO-doped FeCCOCE 400 AC.
The sample was stored in a desiccator.
Dissolve 0.
1 grams of Crystal Violet in 100 after cooling, it was ground using a mortar and mL of distilled water in a 100 mL volumetric pestle so that the sample could be described.
flask, then pipette 10 mL of the Crystal Violet Synthesis of CuO-doped FeCCOCE material 50 mL of methanol, covered with plastic wrap, was used to dissolve FeClCEA6HCCO stock solution and dilute it in a 1000 mL Add photocatalyst to 100 mL of the Crystal Violet Before UV irradiation, the solution was KOVALEN: Jurnal Riset Kimia, 12.
, 2026: 44-52 Ramadhani.
, et al stirred in the dark for 30 minutes to achieve Table 1 illustrates that when the CuO adsorption and desorption equilibrium.
Next, content increases, the band gap energy drops.
the photolysis irradiation times were set to 0.
The ideal composition was found at 20% CuO, 30, 60, 90, 120, 150, and 180 minutes.
5 mL of which had the lowest band gap value .
5 eV).
solution was taken at each interval and then Improved centrifuged for 10 minutes to remove particles.
increased absorption of visible light are To measure the absorbance of the supernatant suggested by this drop.
solution, a UV-Vis spectrophotometer with a Band Gap Value .
V) RESULT AND DISCUSSION Band Gap Energy Analysis UV-DRS was used to examine the optical FeCCOCE/CuO wavelength range (Lakhera et al.
, 2.
The calculate the band gap energy : (E.
F(R) =
5% 10% 15% 20% 25%
CuO Concentration (%) Figure 2.
Band gap energy on the effect of CuO doping concentration .
Oe R)2 The formation of a heterojunction between and calculated using:
Eg = h = photocatalysts in the 185Ae1100 nm instrument KubelkaAeMunk wavelength of 553 nm was used.
FeCCOCE and CuO is responsible for the decrease (Figure This heterojunction introduces new energy levels The band gap values were obtained from the and promotes charge transfer, thereby reducing plot of electronAehole h .
V) versus (F(R).
1/2 The calculated band gap values for FeCCOCE/CuO (Chandra Darmayanti, 2.
Effect of MEA Additive on Band Gap Energy Monoethanolamine (MEA) was added in with different CuO compositions are presented amounts of 1 mL, 2 mL, and 3 mL to further in Table 1.
improve the optical characteristics.
The results Table 1.
Band gap energy of FeCCOCE/CuO No.
Sample Band Gap .
V) FeCCOCE .
FeCCOCE/CuO 5% FeCCOCE/CuO 10% FeCCOCE/CuO 15% FeCCOCE/CuO 20% FeCCOCE/CuO 25% are displayed in Table 2.
Table 2.
Band gap energy with MEA addition No.
Sample Band Gap .
V) 1 FeCCOCE/CuO 1 mL MEA 2 FeCCOCE/CuO 2 mL MEA 3 FeCCOCE/CuO 3 mL MEA KOVALEN: Jurnal Riset Kimia, 12.
, 2026: 44-52 Ramadhani.
, et al Table 2 shows that the addition of 2 mL MEA results in the lowest band gap value .
resulted in a significantly higher degradation of 87% within 30 minutes.
eV), indicating the optimal condition.
Degradation Band Gap Value .
V) MEA volume .
L) Figure 3.
Effect of MEA on band gap energy Time (Minute.
ions, resulting in a more uniform distribution of CuO inside the FeCCOCE matrix (Figure .
MEA
also enhances surface area, decreases particle Degradation During synthesis.
MEA functions as a complexing agent to stabilise FeAA and CuAA size, and regulates crystal growthAiall of which are advantageous for photocatalytic activity (Upadhyay et al.
, 2.
Time (Minute.
Photocatalytic Activity The degradation of Crystal Violet dye under UV and sunlight irradiation was used to assess the photocatalytic activity.
Using a UVVis absorption wavelength .
of Crystal Violet was found to be roughly 590 nm.
The ideal sample (FeCCOCE/CuO 20% with 2 mL MEA) was used in the photocatalytic studies, and the irradiation periods were 30, 60, 90, and 120 minutes.
The degradation results are illustrated in Figure 4.
Photocatalytic Crystal Violet is influenced by both irradiation time and light source.
Under UV irradiation, the efficiency Figure 4.
Photodegradation efficiency of Crystal Violet using FeCCOCE/CuO .
%) with 2 mL MEA under (A) sunlight and (B) UV irradiation The degradation efficiency often rises with radiation time, as seen in Figure 1, suggesting the ongoing production of reactive species such as hydroxyl radicals (AOH) and superoxide radicals (OCCAA), which are essential to the degradation process.
However, the creation of intermediate compounds that still absorb close to the characteristic wavelength of Crystal Violet may cause variations in degradation efficiency at intermediate irradiation durations.
remained low, reaching only 13.
95% after 60 In contrast, exposure to sunlight KOVALEN: Jurnal Riset Kimia, 12.
, 2026: 44-52 Ramadhani.
, et al Discussion FeCCOCE-based The results show that the photocatalytic indicating strong potential for wastewater performance is greatly improved by the creation treatment applications (Gupta & Mandavgane, of Fe2O3/CuO heterostructures and the addition of MEA.
Improved absorption in the visible CuO and MEA work in concert to improve range is indicated by the band gap decreasing the optical characteristics and photocatalytic 49 eV .
ure FeCCOCE) to 1.
6 eV activity of Fe2O3-based materials, suggesting (FeCCOCE/CuO) and then to 1.
81 eV with MEA that they have a great deal of promise for use in wastewater treatment (Irsyad & Sanjaya.
A number of synergistic effects can be used to explain the enhancing mechanism.
Recombination of photogenerated electron-
CONCLUSION
hole pairs is suppressed by the creation of a The research's results show that adding Fe2O3/CuO heterojunction, which is essential MEA to the Fe2O3/CuO photocatalyst results in for increasing charge separation efficiency.
CuO serves as an electron acceptor in this characteristics for the breakdown of Crystal system, promoting electron transport and Violet dye.
CuO was successfully incorporated lowering recombination rates even more.
The into Fe2O3 to lower the band gap energy.
presence of MEA during the synthesis process CuO was found to be the ideal composition.
improves structural homogeneity, leading to a Additionally, the addition of 2 mL MEA more uniform particle dispersion.
Particle size reduction also increases surface area and the number of active sites, both of which improve photocatalytic effectiveness (Ashu Abey et al.
Tests of photocatalytic activity showed that the best sample had a high rate of Improved utilization of the light spectrum is Crystal Violet degradation, reaching about reflected in the higher degradation efficiency 87% in 120 minutes when exposed to under sunlight compared to UV irradiation.
The broader photon energy range provided by The sunlight enhances the generation of reactive During the photocatalytic process, photon absorption excites electrons from the recombination, as well as the function of MEA in regulating particle size and boosting surface producing electronAehole pairs.
These charge carriers subsequently degrade Crystal Violet Fe2O3/CuO electron-hole into simpler and less harmful compounds For the treatment of dye-contaminated through reactions with water and oxygen, wastewater, especially when exposed to sun forming reactive species (AOH and OCCAA).
radiation, the Fe2O3/CuO photocatalyst with CuO and MEA act synergistically to improve the MEA addition can be regarded as a promising, economical, and eco-friendly material.
KOVALEN: Jurnal Riset Kimia, 12.
, 2026: 44-52 Ramadhani.
, et al
ACKNOWLEDGMENT
The authors gratefully acknowledge the Laboratory Chemistry.
Faculty Mathematics and Natural Sciences.
Universitas Negeri Padang, for providing the facilities and instrumentation used in this study.
The authors also appreciate all individuals and colleagues who contributed to the completion of this work, both directly and indirectly.
REFERENCES