Available online at website: https://journal.
id/index.
php/bcrec Bulletin of Chemical Reaction Engineering & Catalysis, 21 .
2026, x-x Original Research Article Photocatalytic Activity of ZnO/Hydroxyapatite Nanocomposite for Remazol Red RB Removal in Aqueous Solution Under UV and Visible Light Irradiation I Dewa Ketut Sastrawidana*.
Luh Putu Ananda Saraswati.
I Nyoman Sukarta.
Ni Made Wiratini.
I Ketut Sudiana.
I Wayan Suja Chemistry Department.
Faculty of Mathematics and Natural Sciences.
Universitas Pendidikan Ganesha.
Singaraja, 81116 Bali.
Indonesia.
Received: 28th November 2025.
Revised: 23th February 2026.
Accepted: 24th February 2026 Available online: 28th February 2026.
Published regularly: August 2026 Abstract Textile industry wastewater contains synthetic dyes that are resistant to natural degradation, toxic, and capable of polluting aquatic environments.
One commonly used dye is Remazol Red RB .
B), which is stable and difficult to remove through conventional treatment methods.
Therefore, an effective approach is needed to break down this This study aimed to develop and characterize a zinc oxide/hydroxyapatite (ZnO/HA) nanocomposite as a photocatalyst for degrading rB dye and to evaluate its photocatalytic performance under UV and visible light The ZnO/HA nanocomposite was prepared by mixing ZnO and HA at a 1:1 ratio, followed by the addition of a small amount of water.
The mixture was milled for 24 hours to obtain nanoscale particles.
The resulting material was calcined at 700 AC and characterized using FTIR.
XRD, and SEM-EDX to determine its physicochemical properties.
Photocatalytic activity tests of the ZnO/HA nanocomposite toward rB dye solution were conducted in a batch system under 50-watt UV and visible light irradiation.
The operational variables examined included catalyst dosage, initial pH, and dye concentration.
FTIR analysis showed characteristic absorption bands of ZnO and HA, indicating successful formation of the nanocomposite.
XRD results revealed a crystal size of 19.
67 nm, while SEM-EDX confirmed the presence of Zn.
Ca.
P, and O elements, consistent with the nanocomposite composition.
The degradation efficiency of 300 mL of 50 mg/L of rB solution at pH of 5 with 2.
0 g of ZnO/HA nanocomposite under 50 watts of UV and visible light in succession was 90.
43% and 80.
93% for 120 minutes of irradiation.
Copyright A 2026 by Authors.
Published by BCREC Publishing Group.
This is an open access article under the CC BY-SA License .
ttps://creativecommons.
org/licenses/by-sa/4.
Keywords: Photocatalytic degradation.
Textile dye.
UV and visible light.
ZnO/HA nanocomposite How to Cite: Sastrawidana.
Saraswati.
Sukarta.
Wiratini.
Sudiana.
Suja.
Photocatalytic Activity of ZnO/Hydroxyapatite Nanocomposite for Remazol Red RB Removal in Aqueous Solution Under UV and Visible Light Irradiation.
Bulletin of Chemical Reaction Engineering & Catalysis, 21 .
, x.
(DOI: 10.
9767/bcrec.
Permalink/DOI: https://doi.
org/10.
9767/bcrec.
Introduction Textile wastewater with high pollutant content, such as heavy metals, suspended particles.
COD, dyes, and other persistent pollutants, is harmful to humans and the environment when itAos discharged directly to the environment without prior treatment .
Approximately 10Ae50% of textile dyes are released into wastewater, and the textile industry is * Corresponding Author.
Email: ketut.
sastrawidana@undiksha.
(I.
Sastrawidan.
estimated to contribute about 17Ae20% of global water pollution .
The presence of colored effluents can reduce sunlight penetration, thereby hindering the photosynthetic activity of aquatic Consequently, anaerobic microbial activity increases, leading to the production of foulsmelling by-products .
Several methods are currently employed to remove color from textile wastewater, including physicochemical processes like electrochemical oxidation, membrane separation, adsorption, photocatalytic degradation, advanced oxidation, bcrec_20548_2025 Copyright A 2026.
ISSN 1978-2993.
CODEN: BCRECO
Bulletin of Chemical Reaction Engineering & Catalysis, 21 .
, 2026, 442 and coagulation .
Biological treatments using fungi and bacteria are also effective .
Semiconductor-assisted photocatalysis has become a popular and affordable green technology that uses photons to break down organic contaminants into innocuous byproducts.
This method has drawn a lot of interest because of its non-selective oxidative characteristics and ability to mineralize organic contaminants into carbon dioxide and water .
In the photocatalytic degradation of pollutants, a semiconductor absorbs light energy at or above its band gap, resulting in electron-hole pairs.
These photoexcited electrons and positive holes then participate in redox reactions that degrade pollutants .
The positive hole interacts with water molecules to produce highly reactive hydroxyl radicals (AOH), while photoexcited electrons react with oxygen molecules to generate superoxide radical anions (AO2A).
These reactive species (AOH and AO2A) work to break down contaminants to harmless byproducts like COCC and H2O .
The photocatalysis method has been widely used for the breakdown of various organic contaminants.
It has also been applied in other domains, such as CO2 reduction and disinfection .
Numerous employed for photocatalysis, including tin oxide .
, .
, iron oxide .
, titanium dioxide .
, zinc oxide .
, and zinc stannate .
Among the available photocatalysts.
TiOCCand ZnO are commonly used for treating pollutants in non-toxicity, biocompatibility, and thermal and chemical stability .
However, the outstanding properties of ZnO, including lower toxicity profiles, stability, ease of synthesis, low material cost, and high biocompatibility, have encouraged the use of ZnO as a promising replacement for TiOCC .
Although the band gap of ZnO is wider .
37 eV) than TiOCC in the anatase phase .
20 eV), the electron mobility of ZnO is higher .
-300 cmA/V.
than TiOCC .
0 cmA/V.
, leading to ZnO photocatalytic applications .
However.
ZnO faces several limitations, including its large band gap, which restricts its effectiveness to the UV spectrum, resulting in diminished visible light Additionally, separating ZnO powder from the reaction solution and implementing continuous flow systems with ZnO presents significant challenges .
Several strategies have been undertaken to enhance the photocatalytic activity of ZnO and enable ZnO to operate under visible light, including doping with metals and non-metals and incorporating materials that function as catalyst supports .
The immobilization of ZnO onto a porous materialAos surface can effectively diminish the band gap energy.
This transpires as a result of the establishment of a heterojunction between the ZnO and support materials, which can reduce the energy necessary for the generation of electronhole pairs so that ZnO could be excited by visible light .
A number of porous materials, such as montmorillonite .
, graphene .
, and carbon .
, .
have been utilized as potential photocatalyst support material composites for removing dyes from aqueous solutions.
Hydroxyapatite, a greener material with the chemical formula Ca10(PO.
6(OH)2, is an emerging catalytic support characterized by remarkable attributes, including large surface area, high mechanical and thermal strength, chemical stability, low water solubility, and large porosity .
In our previous work, hydroxyapatite synthesized using seashells via chemical precipitation was successfully employed as a support material for TiOCC photocatalysts, enabling the degradation of rB dye in aqueous solutions .
The current work involves the preparation of ZnO/HA nanocomposites and the evaluation of their ability to degrade rB dye in wastewater using both UV and visible light This study introduces a sustainable approach in the synthesis of new photocatalysts based on ZnO and HA sourced from seashells.
This innovation provides an environmentally friendly and low-cost alternative as a calcium source for HA synthesis.
The operational variables investigated include the effect of nanocomposite dosage, starting solution pH, and dye concentration on the efficiency of color removal.
Materials and Methods 1 Materials Analytical-grade ZnO .
9% purity.
CAS No.
1314-13-.
was purchased from Sigma-Aldrich.
The rB dye was sourced from a local textile dye supplier in Denpasar.
Bali.
Indonesia.
2 Preparation of ZnO/HA Nanocomposite The ZnO/HA nanocomposite was prepared by blending HA and ZnO at a 1:1 weight ratio, followed by the addition of 60 mL of deionized The resulting suspension was milled for 24 hours using a bead milling machine to reduce the particle size to the nanoscale.
Afterward, the product was dried at 105 AC for 5 hours and subsequently calcined at 700 AC for 3 hours to obtain the final nanocomposite.
3 Characterization of ZnO/HA Nanocomposite FTIR .
erk Shimadzu, type IRPrestige .
analysis revealed the functional groups present in the ZnO/HA nanocomposite.
SEM-EDX .
erk FEI, type Inspect-S.
revealed its surface Copyright A 2026.
ISSN 1978-2993 Bulletin of Chemical Reaction Engineering & Catalysis, 21 .
, 2026, 443 morphology and elemental composition, and XRD .
erk PANalytical, type X'Pert PRO) was employed to determine the crystal size.
Results and Discussion 4 Photocatalytic Degradation Performance The functional group of the synthesized HA.
ZnO, and ZnO/HA composite was observed using FTIR, and their spectra are presented in Figure 1.
The FTIR spectrum exhibits several characteristic absorption bands that confirm the formation of The prominent band observed at 11 cmAA corresponds to the stretching vibration of OH groups, while the band at 628.
cmAA is attributed to the librational mode of OH.
The simultaneous presence of these two bands is widely recognized as a distinctive signature of crystalline hydroxyapatite.
The strong absorption at 1051 cmAA and 1995.
34 cmAA is assigned to the asymmetric stretching vibration of phosphate (POCEAA) groups, which constitute the fundamental structural framework of hydroxyapatite.
The result matches a previous report from Van-Pham et al.
, who reported characteristic P-O absorption bands of PO43- groups at 633 cmAA, 1035 cmAA, and 1995 cmAA .
The band detected at 1668.
12 cmAA is associated with the bending vibration of adsorbed water molecules, indicating the presence of physically bound moisture on the sample Meanwhile, the absorption at 1464.
cmAA and 1668.
12 cmAA confirms the presence of the carbonate (CO32-) functional group.
The ZnO exhibited FTIR spectra at 3736.
cmAA, 3609.
66 cmAA, 2349.
20 cmAA, 1696.
41 cmAA, 28 cmAA, 872.
20 cmAA, 674.
13 cmAA, and 73 cmAA.
The strong absorption bands located 13 cmAA and 524.
73 cmAA are characteristic of ZnAeO stretching vibrations in the ZnO lattice.
The broad absorptions observed at 3736.
63 cmAA 66 cmAA are attributed to the stretching vibrations of OH groups .
The FTIR analysis of ZnO/HA nanocomposite revealed that the IR spectra contained all of the distinctive bands of ZnO and HA.
However, the new band at 522.
70 cmAA could be attributed to the adsorption peak of ZnO species in ZnO/HA .
An absorption band at approximately 2349 cmAA was detected in all analyzed samples.
This band is not associated with the intrinsic functional groups of the constituent materials but is more appropriately attributed to the asymmetric stretching vibration of atmospheric COCC, which was likely adsorbed on the sample surface .
The crystalline structure and size of HA.
ZnO, and ZnO/HA was examined via XRD, and their XRD patterns are presented in Figure 2.
Figure 2 presents the XRD patterns of HA.
ZnO, and the ZnO/HA composite.
For HA, diffraction peaks were detected at 2 values of 25.
591A, 31.
283A, 39.
917A, 46.
810A, and 49.
These reflections are consistent with the standard hydroxyapatite data (JCPDS No.
, which show characteristic peaks at 25.
8A .
, 31.
The photocatalytic degradation of rB dye was conducted in a batch reactor using ZnO/HA nanocomposites as the catalyst.
A 300 mL aqueous solution of dye was placed in a reactor .
y 12 y 10 cmA), followed by the addition of the The suspension was magnetically stirred at 150 rpm to ensure uniform dispersion.
The reactor was immersed in a temperature-controlled water bath to maintain constant reaction conditions and irradiated with a UV lamp (YCRAYS, 395 nm, 50 W).
The operational variables were investigated, including ZnO/HA nanocomposite dosage .
-2 .
, initial pH .
, and dye concentration .
-75 mg/L).
The solution pH was adjusted to the desired value by carefully adding hydrochloric acid (HC.
or sodium hydroxide (NaOH) solution dropwise under continuous stirring until the target pH was Aliquots .
mL) were collected at 15 min intervals over 120 min, filtered through Whatman No.
42 paper, and dye concentration was determined by measuring the absorbance at 518 nm using a UVAeVis spectrophotometer (Merk Shimadzu UV-2600.
With the same procedure, the photocatalytic degradation process is also carried out using visible light as a radiation The degradation efficiency of dye was calculated using the formula:
yayayayayayayayayayayayayayayayayayayayayaya yceyceyceyceyceyceyceyceyceyceyceyceyceyceyceyceyceyceyceyce (%) = yayayayaOeyayayaya yayayaya ycuycu 100% .
Here.
A0 and At denote the dyeAos absorbance at the initial time and at time t, respectively.
Figure 1.
FTIR spectral profiles for HA.
ZnO and ZnO/HA nanocomposite.
Characteristic of HA.
ZnO, and ZnO/HA Nanocomposite Copyright A 2026.
ISSN 1978-2993 Bulletin of Chemical Reaction Engineering & Catalysis, 21 .
, 2026, 444 .
, 32.
9A .
, 46.
7A .
, and 49.
4A .
The hexagonal phase of HA is typically identified by an intense peak near 31.
7A, accompanied by adjacent reflections around 32.
2A and 33.
confirming the formation of crystalline HA.
The XRD pattern of ZnO displays prominent peaks at 31.
939A, 34.
509A, 36.
336A, 47.
781A, 63.
072A, 66.
472A, 68.
129A, 69.
644A, 77.
041A, 81.
658A, and 89.
accordance with JCPDS card No.
36-1451, the reflections at 31.
939A, 34.
509A, 36.
336A, 47.
781A, and 68.
129A correspond to the .
, .
, .
, .
, .
, and .
planes, respectively, indicating the typical wurtzite structure of ZnO.
For the ZnO/HA composite, combined diffraction peaks were observed at 2 values of 17.
920A, 26.
037A, 28.
709A, 31.
509A, 36.
336A, 47.
649A, 56.
781A, 63.
472A, 68.
129A, 69.
245A, 72.
644A, 77.
658A, and 89.
792A, demonstrating the coexistence of both HA and ZnO crystalline phases in the composite material.
The crystallite size of each sample was determined using the Scherrer equation .
yaya = yayayaya In this expression.
D refers to the crystallite size .
K denotes the Scherrer constant with a typical value of 0.
90, yuIyuI represents the wavelength of the CuAeK X-ray radiation .
154 n.
, represents the full width at half maximum (FWHM) of the diffraction peak .
n radian.
, and indicates the BraggAos angle associated with the diffraction peak.
Based on X-ray diffraction data, the average crystallite size was calculated using the Scherrer equation, obtaining 25.
66 nm for HA, 67 nm for ZnO, and 19.
20 nm for ZnO/HA The surface characteristics and elemental composition of ZnO.
HA, and the ZnO/HA nanocomposite were examined using SEMAeEDX Figure 3 presents the morphological Figure 2.
The XRD diffraction profiles for HA.
ZnO and the ZnO/HA nanocomposite.
features of pure ZnO, pure HA, and the distribution of ZnO particles on the HA surface.
SEM analysis reveals that ZnO exhibits a rodshaped morphology characterized by a porous
and moderately rough surface, implying the presence of hollow features and partial
(HA)
precipitation method predominantly shows a The compositional analysis obtained from EDX indicates an average Ca/P ratio of 1.
67, which is in good agreement with the stoichiometric value of hydroxyapatite.
In the ZnO/HA nanocomposite.
SEM images display agglomerated granular nanoparticles with a rough and porous texture.
The ZnO phase is well distributed throughout the hydroxyapatite matrix, forming a heterogeneous architecture that is expected to improve adsorption capability and photocatalytic activity by enlarging the effective surface area and strengthening interfacial interactions.
Elemental mapping further confirms the spatial distribution of each component, where Zn species derived from ZnO are represented in yellow regions and Ca originating from HA appears in cyan regions, verifying the successful incorporation of ZnO onto the HA support.
The EDX spectra for the ZnO/HA nanocomposite, as presented in Figure 4, confirm the presence of all the expected elements (Zn.
Ca.
P, and O) specific to the HA and ZnO components.
The detection of carbon (C) is likely attributed to the adsorption of atmospheric carbon dioxide (COCC) on the surface of hydroxyapatite.
2 Photocatalytic Degradation Studies of rB Dye The photocatalytic degradation of azo dyes begins when ZnO is irradiated with light of sufficient energy, generating electrons in the conduction Figure 3.
SEM-EDX images of ZnO.
HA and ZnO/HA nanocomposite.
Copyright A 2026.
ISSN 1978-2993 Bulletin of Chemical Reaction Engineering & Catalysis, 21 .
, 2026, 445 band .
A) and holes in the valence band .
A).
The photogenerated holes .
A) oxidize surfaceadsorbed HCCO or OHA to produce hydroxyl radicals (AOH), while the conduction band electrons .
A) reduce molecular oxygen (OCC) to form superoxide radicals (AOCCA).
In the presence of protons (HA), superoxide radicals can subsequently generate hydroperoxyl radicals (HOCCA) and hydrogen peroxide (HCCOCC).
Furthermore, the reaction between AOCCA and HCCOCC leads to the formation of additional hydroxyl radicals .
ZnO hI Ie eOeCB h VB h VB H2O Ie AOH H h VB OHOe Ie AOH eOeCB O2 Ie AOCCA AOCCA H Ie HOCCA HO2A HO2A Ie H2O2 O2 H2O2 AOCCA Ie AOH OHOe O2 Hydroxyl radicals are the primary reactive species responsible for the breakdown of azo dye The rB, classified as an azo dye, contains the characteristic functional group represented by the general structure R1-N=N-R2.
These reactive species attack and cleave the azo linkage, transforming the original azo dye into simpler end products.
H2O and CO2 .
AOH R1-N=N-R2 Ie R1-NH2 R2-NH2 romatic amine.
AOH aromatic amines Ie Simple degradation product CO2 H2O In this study, 300 mL of rB solution at a concentration of 25 mg/L was treated separately with 2 g of pristine ZnO and 2 g of the ZnO/HA nanocomposite at an initial pH of 7 and irradiated with both UV and visible light for 120 minutes.
The purpose of this investigation was to evaluate the role of HA as a support material in enhancing the photocatalytic performance of ZnO for dye The resulting photodegradation efficiencies are presented in Figure 5.
Figure EDX nanocomposite powder.
ZnO/HA The results in Figure 5 show that the ZnO/HA nanocomposite exhibited superior photocatalytic activity compared with pristine ZnO under both UV and visible light exposure.
Under UV irradiation, the removal efficiency of rB reached 90.
78% in the presence of ZnO/HA, slightly higher than that achieved by ZnO alone .
15%).
A more pronounced difference was observed under visible light, where the nanocomposite achieved 80.
degradation, whereas pure ZnO showed only 53% removal efficiency.
Integrating ZnO with photocatalytic efficiency for dye degradation under light irradiation.
Owing to its large specific surface area, hydroxyapatite provides abundant adsorption sites that facilitate close contact between dye molecules and the active ZnO Moreover, hydroxyapatite exhibits a point of zero charge .
Hpz.
of approximately 8.
, therefore, at pH values below this point, its surface becomes positively charged.
This positive surface charge promotes strong electrostatic attraction toward Rb, an anionic azo dye, thereby improving pollutant adsorption and accelerating the degradation process.
In addition, the heterojunction formed between ZnO and hydroxyapatite enhances the separation of photogenerated electronAehole pairs, suppresses their recombination, and sustains higher photocatalytic activity compared with pristine ZnO .
This finding is consistent with VaizogullarAos results, who reported that ZnO/Bent degradation compared to ZnO in degrading the oxytetracycline antibiotic under UV light .
addition, research by Zhang et al.
that TiO2/MXene composites enhance both the degradation efficiency and the degradation rate of methylene blue dye .
Figure 5.
Degradation efficiency of dye with ZnO and ZnO/HA.
Copyright A 2026.
ISSN 1978-2993 Bulletin of Chemical Reaction Engineering & Catalysis, 21 .
, 2026, 446 Effect of ZnO/HA Dose on Photocatalytic Degradation Efficiency To evaluate the influence of catalyst loading on photocatalytic performance, 300 mL of rB solution .
mg/L) was placed in the photoreactor.
The solution pH was adjusted to 7 prior to adding varying amounts of ZnO/HA nanocomposite .
5, 2.
0, and 2.
The corresponding degradation efficiencies of rB at different catalyst dosages are presented in Figure 6.
Catalyst loading plays a vital role in determining photocatalytic performance.
Increasing the amount of photocatalyst generally provides more active sites in the reaction system, thereby promoting greater photon absorption and enhancing the formation of reactive species such Nevertheless, excessive catalyst addition may adversely affect performance.
Higher solid concentrations can increase solution turbidity, intensify light scattering, and ultimately limit photon penetration to the catalyst surface .
illustrated in Figure 6, raising the ZnO/HA dosage from 1.
0 g to 2.
0 g significantly improved the photocatalytic activity, which can be attributed to the greater availability of active However, when the dosage was further increased to 2.
5 g, only a slight enhancement in degradation efficiency was observed, likely due to restricted light transmission within the This finding is in accordance with the research of Bekhit et al.
who reported that there was an increase in the efficiency of tetracycline photocatalytic degradation along with increasing MgONPs dosage from 0.
1 to 0.
6 g/L and then tended to decrease with the addition of 1.
0 g/L .
Impact of pH on photocatalytic degradation The solutionAos pH is a key factor in photocatalytic processes because it controls the At this stage, a 300 mL rB dye solution of 25 mg/L concentration was converted with a ZnO/HA photocatalyst mass of 2 g.
The degradation efficiency of the dye at different pH conditions .
is presented in Figure 7.
Figure 6.
Effect of ZnO/HA dose on photocatalytic degradation efficiency.
Figure 7.
Photocatalytic degradation efficiency at different pH.
Copyright A 2026.
ISSN 1978-2993 Bulletin of Chemical Reaction Engineering & Catalysis, 21 .
, 2026, 447 The degradation efficiency of rB initially increased and then declined as the pH was raised from 5 to 10, with the highest removal achieved at pH of 5.
The degradation efficiency of rB initially increased and then declined as the pH was raised from 5 to 10, with the highest removal achieved at pH of 5.
The influence of pH on the photocatalytic performance of the ZnO/HA composite can be explained by considering the point of zero charge .
HPZC) and the resulting surface charge of the catalyst.
According to Alhasan et al.
ZnO has a pHPZC of 8.
4, indicating that its surface is positively charged at pH values 4 due to protonation and negatively charged at pH values above 8.
Under acidic conditions, the abundance of HA ions promotes protonation of the ZnO/HA surface, making it more positively charged.
This enhances electrostatic attraction between the positively charged catalyst surface and the anionic rB dye molecules, facilitating stronger adsorption and improved photocatalytic degradation.
contrast, at alkaline pH, both the ZnO/HA surface and the anionic dye carry negative charges, resulting in electrostatic repulsion.
This repulsive interaction reduces dye adsorption onto the catalyst surface and consequently lowers the degradation efficiency .
Impact of Initial Dye Concentration on Photocatalytic Degradation Performance Studying the effect of dye concentration on photocatalytic performance is very important for the practical design of photocatalytic treatment At this point, 300 mL of rB dye solution with concentrations ranging from 25 to 75 mg/L was subjected to treatment with 2 grams of a ZnO/HA nanocomposite.
The photocatalytic reaction process was performed at pH of 5 using separate 50-watt UV and visible light irradiation for 120 min, with dye color removal monitored every 15 min of treatment.
The efficiency of dye degradation is presented in Figure 8.
Figure 8 illustrates that higher dye concentrations resulted in lower photocatalytic When concentration was raised from 25 mg/L to 75 mg/L, the removal efficiency dropped from 94.
06% to 90% under UV light and from 81.
37% to 61.
under visible light, with a consistent treatment time of 120 min.
This study found that the optimal concentration of dye that can be processed to produce optimum efficiency is 50 mg/L at an initial pH treatment condition of 5, with 2 g of ZnO/HA nanocomposite.
Under these conditions, the degradation efficiency for the reactor irradiated with UV and visible light for 120 min 43% and 80.
93%, respectively.
At higher dye concentrations, photocatalytic degradation efficiency often declines because the dye molecules can absorb most of the light, hindering it from reaching the photocatalyst .
This reduced light absorption limits the formation of electron-hole pairs, which are essential for the degradation process .
Previous work conducted by Sukarta et al.
also demonstrated that the photocatalytic degradation efficiency of rhodamine B using HAAe ZnO composite under UV irradiation declined noticeably as the initial dye concentration increased .
Conclusions In this study, a photocatalytic reaction using a 1:1 ZnO/HA nanocomposite effectively degraded 300 mL of 50 mg/L Remazol RRB solution.
Irradiation with 50 watts of UV and visible light for 120 minutes at pH of 5 resulted in degradation efficiencies of 90.
43% and 80.
93%, respectively.
Thus.
ZnO/HA composite can be effectively utilized as a cheaper natural supporting catalyst for the removal of dye from aqueous medium.
Figure 8.
Effect of dye concentration on photocatalytic degradation efficiency.
Copyright A 2026.
ISSN 1978-2993 Bulletin of Chemical Reaction Engineering & Catalysis, 21 .
, 2026, 448 Acknowledgment .
This research was financially supported by the Research and Community Service Universitas Pendidikan Ganesha, with contract number 1254/UN48.
16/LT/2024.
All the authors thank the Chemistry Department for laboratory facilities.
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CRedit Author Statement Author Contributions: I Dewa Ketut Sastrawidana: Conceptualization.
Design of methodology.
Resources.
Investigation.
Writinginitial draft preparation.
Luh Putu Ananda Saraswati: Resources.
Investigation.
Data curation.
Formal analysis.
I Nyoman Sukarta:
Formal Investigation.
Data presentation.
Review and editing manuscript.
Made Wiratini: Software.
Formal analysis.
Review and editing of manuscript.
I Ketut Sudiana: Formal analysis.
Review and editing of I Wayan Suja: Resources.
Data curation.
Review and editing of manuscript.
All authors have read and agreed to the published version of the manuscript.
References