Available online at website: https://journal.
id/index.
php/bcrec Bulletin of Chemical Reaction Engineering & Catalysis, 21 .
2026, 96-111 Original Research Article Green-Modified Ni/Al LDH with Camellia sinensis Bioactives: A Sustainable Strategy for Ceftriaxone Removal Amri Amri1,2.
Najma Annuria Fithri3.
Muhammad Said4.
Aldes Lesbani2,5* 1Doctoral Program of Environmental Science.
Postgraduate Program.
Universitas Sriwijaya.
Palembang, 30139.
Indonesia.
2Research Center of Inorganic Materials and Coordination Complexes.
Universitas Sriwijaya.
Palembang, 30139.
Indonesia.
3Department of Pharmacy.
Faculty of Mathematics and Natural Sciences.
Universitas Sriwijaya.
Ogan ilir, 30862.
Indonesia.
4Department of Chemical Engineering.
Faculty of Engineering.
Universitas Sriwijaya.
Ogan ilir, 30862.
Indonesia.
5Magister Program of Materials Science.
Graduate School Universitas Sriwijaya.
Palembang, 30139.
Indonesia.
Received: 14th October 2025.
Revised: 5th December 2025.
Accepted: 6th December 2025 Available online: 15th December 2025.
Published regularly: April 2026 Abstract Ceftriaxone (CEF) is a -lactam antibiotic widely used in the medical field to treat various bacterial infections in both humans and animals.
The high usage of CEF has the potential to cause environmental pollution and antimicrobial resistance, necessitating effective treatment methods.
In this study, the adsorption method is proposed using Ni/Al layered double hydroxide (LDH) and Camellia sinensis extract-modified material (Ni/Al-CS.
as a sustainable biomodification approach.
The results show the optimal adsorption pH for Ni/Al LDH is 3 and for Ni/Al-CSe is 5, with the adsorption isotherms following the Freundlich model and the kinetics conforming to pseudo-first order (PFO).
The maximum adsorption capacity (Q.
significantly increased from 28.
818 mg.
g-1 (Ni/Al LDH) to 111.
111 mg.
g-1 (Ni/AlCS.
Thermodynamic analysis revealed that adsorption on both materials proceeds spontaneously, while the consistently more negative iG values and predominantly exothermic behavior of Ni/Al-CSe confirm its superior thermodynamic favorability associated with more specific surface interactions.
Regeneration tests up to four cycles showed that Ni/Al-CSe was more stable than Ni/Al LDH.
Overall, modifying Ni/Al LDH with Camellia sinensis extract was proven to enhance adsorption capacity, spontaneity, and stability, providing an effective and environmentally friendly solution for antibiotic treatment.
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: Ni/Al LDH.
Camellia sinensis.
Composite.
Adsorption.
Ceftriaxone How to Cite: Amri.
Fithri.
Said.
Lesbani.
Green-Modified Ni/Al LDH with Camellia sinensis Bioactives: A Sustainable Strategy for Ceftriaxone Removal.
Bulletin of Chemical Reaction Engineering & Catalysis, 21 .
, 96-111.
oi: 10.
9767/bcrec.
Permalink/DOI: https://doi.
org/10.
9767/bcrec.
Introduction In recent decades, the use of pharmaceutical drugs has increased rapidly worldwide.
More than 200,000 tons of medication are consumed annually to treat various human diseases, including steroid hormones, anti-inflammatory drugs, and antibiotics.
It is known that between 30 and 90% of drug compounds, both in their * Corresponding Author.
Email: aldeslesbani@pps.
id (A.
Lesban.
parent form and as active metabolites, can be excreted thru urine and feces.
As a result, these compounds can enter the aquatic environment without undergoing complete degradation .
Among antibiotics are one of the most frequently detected wastes in water bodies.
This is due to the disposal of antibiotics in their original form or as metabolites thru domestic waste, the disposal of expired drugs, and the activities of the .
Therefore, bcrec_20513_2025 Copyright A 2026.
ISSN 1978-2993.
CODEN: BCRECO
Bulletin of Chemical Reaction Engineering & Catalysis, 21 .
, 2026, 97 antibiotics show an increase in the accumulation and persistence of this substance in the Additionally, the large-scale consumption of antibiotics, by both humans and environmental burden, as most residues are disposed of without adequate treatment processes .
The excessive and inappropriate use of antibiotics has resulted in antibiotic-resistant bacteria and resistance genes, which have been found in drinking water, posing a significant threat to human health .
Ceftriaxone sodium (CEF) is a thirdgeneration semi-synthetic antibiotic from the lactam cephalosporin group .
Ae.
Due to its resistance to the -lactamase enzyme.
CEF is widely used in the medical world to treat various bacterial infections in humans and animals .
Because of its high usage, some of this chemical residue remains in the body and is eventually released into water thru excretion, household waste, and pharmaceutical industrial activities .
Its presence in the environment poses a significant problem because CEF compounds can affect microorganisms, plants, aquatic animals, and even human health by disrupting the ecosystem balance, even at low concentrations .
To address antibiotic pollution in the environment, including CEF, various methods have been developed, including physical, chemical, and biological processes.
Membrane filtration, nanofiltration, reverse osmosis, ion exchange, activated sludge systems.
Fenton-like reactions, ozonation, photolysis, and magnetic ion exchange resins are some commonly used techniques .
,12,.
However, most of these methods have limitations despite being effective in certain situations.
Conversely, the adsorption method has emerged as one of the most promising approaches in wastewater treatment due to its many advantages, including simplicity, low operating costs, the absence of hazardous byproducts, and high effectiveness in removing various contaminants, including antibiotics .
,14Ae.
The selection of adsorbent material is a crucial factor in the CEF adsorption process, as influence the efficiency of pollutant removal .
One material that has received significant attention is layered double hydroxide (LDH), which is a group of solids with a brucite-like structure and the general formula [MII.
Mix(OH).
x A(An-).
AyH2O, where MII and Mi are divalent cations .
Mg2 .
Zn2 .
Ni2 .
Ca2 .
Fe2 ) and trivalent cations .
uch as: Al3 .
Fe3 .
Cr3 .
Ga3 ), while An- is an exchangeable anion in the interlayer space .
Ae.
The layered structure gives LDH high anion exchange capacity, large surface area, good thermal stability, and ease of synthesis at relatively low cost, making this material widely used in various electrochemistry, and contaminant removal in water thru adsorption .
Despite its various advantages, the use of pure LDH still faces some limitations.
This material tends to agglomerate in aqueous environments, thus reducing the active surface area available for interaction with pollutants .
Additionally, pure LDH is reported to have low regeneration, which limits its effectiveness in repeated applications .
These limitations have prompted many researchers to develop composite-based LDH with the addition of supporting materials or modification using natural compounds, aiming to improve stability, prevent agglomeration, and enhance adsorption performance .
Various previous studies have shown that the creation of LDH-based composites with the addition of other materials can significantly improve adsorption performance.
For example, the ZnCr-LDH/Spirogyra algae composite showed a significantly higher adsorption capacity for Direct Yellow compared to pure LDH, with the Qm value increasing from 22.
727 mg/g for ZnCrLDH to 48.
780 mg/g for ZnCr-LDH/ Spirogyra algae, while maintaining a removal efficiency of 37% after five cycles of use .
The Ni/Al-LDH composite with magnetic humic acid (Ni/Al-MAH) also proved to increase the adsorption capacity 966 mg/g for pure LDH to 178.
571 mg/g, indicating synergy between LDH and the magnetic organic material .
Another study reported that red mud/LDH nanocomposites are effective for the adsorption of the antibiotic sulfamethoxazole, with good regeneration ability up to six cycles without significant capacity reduction .
Additionally, the utilization of natural material extracts as a modification component also shows promising potential.
For example.
MgAl-LDH Hylocereus costaricensis extract were reported to be reusable for up to three cycles without significant reduction in adsorption performance .
Similarly.
NiFeLDH composites with gambir leaf extract were able to be reused for up to five cycles with stable adsorption capacity .
The Zn/Al-LDH composite modified with thyme extract showed a maximum adsorption capacity (Q.
751 mg/g for methylene blue .
Biological extract of Cynomorium coccineum has been used to synthesize copper nanoparticles with copper sulfate precursor, resulting in an adsorption capacity (Q.
of 64 mg/g for methylene blue .
Additionally, magnetite nanoparticles (Fe3O.
produced by green synthesis using Moringa Copyright A 2026.
ISSN 1978-2993 Bulletin of Chemical Reaction Engineering & Catalysis, 21 .
, 2026, 98 oleifera extract were reported to remove the antibiotic levofloxacin with an adsorption capacity 47 mg/g .
These results confirm that integrating LDH with biological materials and natural extracts not only enhances adsorption capacity but also improves regeneration properties and the sustainability of its use.
Although showing potential, the research still has limitations, including the fact that studies with thyme and Cynomorium coccineum extract were only tested on simple pollutants like methylene blue, while the use of Moringa oleifera extract still has low capacity against antibiotics.
In this context, green tea leaf extract (Camellia sinensi.
becomes an interesting modification compounds such as polyphenols and flavonoids rich in hydroxyl groups, thus potentially enhancing the interaction between the composite material and antibiotic molecules .
The presence of hydroxyl and aromatic groups in these interactions with the LDH surface, thereby enhancing the adsorption capacity and selectivity of the composite material toward complex organic pollutants such as antibiotics .
Thus, the utilization of green tea leaf extract as an LDH modification agent is considered an innovative and environmentally friendly approach to enhance the performance of adsorbent materials.
Based on this background, this study aims to synthesize and evaluate the performance of Ni/Al layered double hydroxide (LDH) and its composite modified with green tea leaf extract (Camellia sinensi.
, namely Ni/Al-CSe, in the adsorption process of the antibiotic CEF from aqueous This study includes characterization of material surface structure and properties, regeneration tests to assess its sustainability.
With this approach, it is hoped that composite materials will be obtained that are not only effective in removing antibiotics, but also support environmentally friendly pharmaceutical waste treatment strategies.
Materials and Method Chemicals and Instrumentation Green tea leaves (Camellia sinensi.
are commercially obtained from the Mount Dempo area.
South Sumatra.
Indonesia.
Chemicals of analytical purity were used in this study, namely nickel nitrate hexahydrate (Ni(NOCE)CCA6HCCO), sodium carbonate (NacOCE), ethanol .
HCIOH), aluminum nitrate nonahydrate (Al(NOCE)CEA9HCCO) (Sigma-Aldric.
Sodium hydroxide (NaOH) and sodium chloride (NaC.
(Merc.
, as well as hydrochloric acid (HCl.
LabGuardA), were used as Locally produced distilled water was used in all stages of synthesis and washing.
The antibiotic ceftriaxone (CEF) was obtained from Bernofarm.
Indonesia.
The material was characterized using various instruments, including an X-ray diffractometer (XRD.
Rigaku MiniFlex .
to evaluate its crystal structure, an FTIR spectrophotometer (Shimadzu Prestige-.
to identify functional groups, and a scanning electron microscope (SEM.
Thermo Scientific Quattr.
to observe the surface Specific surface area and pore distribution were determined using the BrunauerAeEmmettAeTeller (BET) method with a BET analyzer (Nova 2200.
Meanwhile, the concentration of ceftriaxone (CEF) was measured using a UV-Vis spectrophotometer (Biobase BKUV 1800 PC serie.
at a wavelength of 240 nm.
Synthesis of Ni/Al LDH .
Ni/Al LDH was synthesized via the coprecipitation method.
A 100 mL precursor solution containing 0.
75 M Ni(NOCE)CC.
6HCCO and 25 M Al(NOCE)CE.
9HCCO was prepared in a beaker.
Next, a mixture of 50 mL 2 M NaOH and 100 mL 2 M NacOCE was slowly added to the precursor solution while stirring, until the pH reached 10.
The reaction suspension was then maintained at 80 AC with constant stirring for 17 hours.
The formed precipitate is filtered, washed with distilled water, and then dried.
The synthesized material was then analyzed using XRD.
FTIR.
SEM, and BET.
Green Extraction Tea (Camellia Leaf The extraction procedure for green tea leaves (Camellia sinensi.
was carried out based on a modified method from Han et al.
Fresh tea leaves are dried and ground into a fine powder.
The extraction process was carried out using the maceration method with 96% ethanol as the The dried leaf powder was soaked in ethanol and left at room temperature for 1 hour.
The resulting mixture was then filtered, and the ethanol solvent was removed using a rotary evaporator at 48 AC.
The concentrated extract obtained was stored at low temperature until used for the material synthesis stage.
Preparation of Ni/Al-CS Composites Ni/Al-CSe composite was synthesized using the coprecipitation method with natural material modification .
eferring to Luo et al.
with some A precursor solution containing NiAA and AlAA in a molar ratio of 5:1 was prepared in 200 mL of distilled water, then 0.
5 g of CS leaf extract was added.
Subsequently, 0.
5 M NaOH solution was added dropwise until the pH reached 10, and the suspension was continuously stirred Copyright A 2026.
ISSN 1978-2993 Bulletin of Chemical Reaction Engineering & Catalysis, 21 .
, 2026, 99 for 24 hours until homogeneous.
The formed precipitate is separated by filtration, washed with distilled water until neutral, and then dried in an The resulting dry powder was used as a Ni/Al-CSe composite.
Determination of the point of zero charge .
Hpz.
The zero point of charge .
Hpz.
of Ni/Al LDH and Ni/Al-CSe was determined using the pH drift A 20 mL solution of 0.
1 M NaCl with an initial pH adjusted within the range of 2Ae10 .
1 M HCl or 0.
1 M NaOH) was mixed with 02 g of the sample.
The mixture was stirred in a shaker for 24 hours at room temperature, and then the final pH was measured with a pH meter.
The difference between the initial and final pH .
pH) is calculated, and the pHpzc value is obtained from the graph of the relationship between the initial pH and ipH at the intersection with the line ipH = 0.
Adsorption of CEF Adsorption experiments were conducted to study the influence of several operating parameters, namely solution pH .
, contact time .
-120 minute.
for adsorption kinetics studies, initial CEF concentration .
-30 mg.
L-.
and temperature .
Ae50 AC) for isotherm and thermodynamic studies, as well as variations in adsorbent dosage .
In each experiment, 20 mL of CEF solution was mixed with Ni/Al LDH or Ni/Al-CSe adsorbent, then shaken using a shaker until the predetermined contact time was reached.
After the process is complete, the suspension is separated and the concentration of residual CEF is analyzed using a UV-Vis spectrophotometer at a wavelength of 240 nm.
Regeneration studies were conducted for up to four cycles, observing the percentage adsorption results from the first to the last cycle.
Additionally, desorption tests were conducted separately to understand the adsorption At this stage, the adsorbed CEF was eluted using several reagents, namely distilled water (DW).
NaOH.
HCl, distilled water with ultrasonic assistance (DW US), and ethanol (EtOH).
The adsorption capacity .
at time t is calculated using the following equation:
ycycycyc = .
aya0 Oeyayaycyc )ycOycO ycoyco C0 is initial concentration .
L-.
Ct is concentration at time t .
L-.
V is volume of CEF solution (L), and m is mass of adsorbent .
Results and Discussion Characterization of the Adsorbent Materials The XRD diffraction patterns for Ni/Al LDH and Ni/Al-CSe are shown in Figure 1.
The Ni/Al LDH material exhibits characteristic peaks Figure 1.
XRD patterns and .
FTIR spectra of Ni/Al LDH and Ni/AlAeCSe, and .
UV-Vis wavelength scan spectrum of CSe.
Copyright A 2026.
ISSN 1978-2993 Bulletin of Chemical Reaction Engineering & Catalysis, 21 .
, 2026, 100 at 2 angles of 11.
39, 23, 34.
86, 39.
41, 47.
81, and 62.
05 with crystal planes .
, .
, .
, .
, .
, .
, and .
, which are consistent with JCPDS reference data No.
150087, confirming the formation of the typical layered double hydroxide lamellar structure .
After modification with Camellia sinensis extract (Ni/Al-CS.
, the XRD pattern still shows the main peaks of Ni/Al LDH, although the relative intensity has changed and a broader background has appeared around 2 of 20Ae30A.
This phenomenon indicates the contribution of amorphous organic compounds from the green tea leaf extract, which are dispersed on the surface or interact with the LDH layers .
The FT-IR spectra of Ni/Al LDH and Ni/AlCSe can be seen in Figure 1.
In Ni/Al LDH, the broad absorption band around 3450 cm-1 is related to the -OH stretching vibrations of hydroxyl groups within the LDH layers as well as water molecules trapped between them .
Meanwhile, the band at 1630 cmAA originates from the bending vibration of HCCO molecules, and the intense band around 1380 cm-1 confirms the presence of nitrate anions (NO3-) which commonly occupy the interlayer space of LDH .
After modification with Camellia sinensis extract (Ni/Al-CS.
, the spectrum shows additional bands in the region of 2920Ae2850 cm-1 related to CAeH stretching from organic compounds, as well as bands around 1050Ae1100 cm-1 associated with CAe O vibrations from phenolic or alcohol groups.
The presence of this band indicates that the bioactive compounds from the green tea leaf extract were successfully immobilized on the material.
The band appearing around 1465 cm-1 is related to the stretching of aromatic C=C, while the strong band at 1635 cm-1 can be attributed to the C=O vibration of flavonoids, polyphenols, and The broad band at 3284Ae3450 cm-1 reflects the OAeH stretching of phenols and flavonoids .
Additionally, the absorption bands in the low wavenumber region <1000 cm-1 are associated with metal-oxygen vibrations (MO, where M = Ni and A.
These bands persist in Ni/Al-CSe, confirming that the basic LDH structure remains intact after modification.
The CSe spectrum wavelength scan (Figure 1.
) shows a broad absorption band in the range of 200-350 nm with four main deconvoluted peaks at 220, 243, 276, and 304 nm, indicating successful synthesis and the formation of active compounds in CSe.
The peaks at 220 nm and 276 nm indicate the presence of catechin compounds, the dominant component in green tea extract, which are associated with AIe A* transitions in the benzene ring aromatic system .
The peak at 243 nm, which occurs within the range of 240-285 nm, can be attributed to electron transitions in the benzoyl band, while the peak at 304 nm, which occurs within the range of 300Ae385 nm, represents transitions in the cinnamoyl band in the flavonoid structure .
This absorption pattern confirms that the CSe contains catechin and flavonoid compounds with a strong conjugated aromatic system, which is an indicator of the successful synthesis process and the formation of bioactive components that have the potential to improve the performance of the Ni/Al-CSe material.
Morphological analysis using SEM (Figure 2aAe.
reveals that Ni/Al LDH exhibits a plateletlike layered aggregate morphology with an average particle diameter of approximately 4.
AAm, as obtained from particle size distribution The particles form relatively compact aggregates, which are attributed to the restacking of LDH nanosheets during drying and sample preparation, leading to overlapping plate After modification with Camellia sinensis extract (Ni/Al-CS.
, the morphology becomes more heterogeneous with looser and less compact agglomeration, accompanied by an increase in the average particle size to 5.
83 AAm.
This change is associated with the adsorption of organic components from the CSe on the LDH surface, which can act as a spacer between interactions and influencing the aggregation Consequently, particles with more irregular shapes and larger apparent sizes are formed compared to pristine LDH.
Characterization of pore texture thru nitrogen adsorption-desorption analysis (Figure 2.
) shows that both materials have type IV isotherms with H3 hysteresis, which is characteristic of mesoporous materials .
-50 n.
However, pore texture parameters showed significant differences.
Pure Ni/Al LDH has a high specific surface area of 83.
89 m2/g, with a pore volume of 0.
23 cm3/g and a pore size of 6.
After modification with CSe, the specific surface area value drastically decreased to 18.
m2/g, with a pore volume of 0.
014 cm3/g and a pore size of 3.
40 nm.
This decrease in surface area can be explained by the presence of organic molecules from the CSe that partially cover the active sites or enter the LDH pore cavities, thus reducing nitrogen accessibility during BET analysis.
However, the presence of these organic compounds can actually enrich the functional properties of the material thru the contribution of active groups such as AeOH.
AeC=O, and aromatic bonds from polyphenols, making Ni/Al-CSe remain competitive and potentially superior in antibiotic adsorption applications compared to Ni/Al LDH.
Adsorption Study Determining the point of zero charge .
Hpz.
is an important parameter for understanding the Copyright A 2026.
ISSN 1978-2993 Bulletin of Chemical Reaction Engineering & Catalysis, 21 .
, 2026, 101 surface charge properties of the adsorbent and understanding the mechanism of interaction with the adsorbate .
The pHpzc values of Ni/Al LDH and Ni/Al-CSe, determined using the ipH method, are shown in Figure 3.
The pHpzc value for Ni/Al LDH was recorded at pH of 7.
34, while Ni/Al-CSe showed a shift to a lower value, at pH Figure 3.
shows that the maximum adsorption capacity was achieved at pH of 3 for Ni/Al LDH and pH of 5 for Ni/Al-CSe.
Under conditions where pH < pHpzc, the adsorbent surface is positively charged, allowing for more effective electrostatic interactions with the negatively charged groups of ceftriaxone molecules .
uch as electron-rich aromatic ring.
Conversely, at pH > pHpzc, the adsorbent surface is negatively charged, leading to electrostatic repulsion with CEF molecules, which also tend to be negatively charged under basic Additionally.
Ni/Al-CSe exhibited higher adsorption capacity compared to Ni/Al LDH across the entire pH range.
This can be attributed to the contribution of bioactive compounds from the tea leaf extract, which contains polyphenols and flavonoids, acting as additional sites for Figure 2.
SEM images and particle size distributions of .
Ni/Al LDH and .
Ni/Al-CSe, and .
NCC adsorptionAedesorption isotherms (BET analysi.
of both materials.
Copyright A 2026.
ISSN 1978-2993 Bulletin of Chemical Reaction Engineering & Catalysis, 21 .
, 2026, 102 interaction with antibiotics.
Thus, modification of LDH Ni/Al using CSe not only affects surface properties .
Hpz.
but also enhances overall adsorption capacity.
The adsorption behavior of CEF by Ni/Al LDH and Ni/Al-CSe as a function of time can be seen in Figure 4.
Both materials show a fairly sharp increase in adsorption capacity in the initial stage .
-40 minute.
due to the abundance of active sites still available on the surface.
As time goes on, the rate of adsorption decreases and reaches equilibrium at around the 75th minute.
After that point, the adsorption capacity remains relatively constant, indicating that most of the active sites have been occupied, resulting in no significant additional adsorption.
At equilibrium, the maximum adsorption capacity recorded was 13.
mg/g for Ni/Al LDH and 14.
50 mg/g for Ni/Al-CSe.
The higher adsorption performance of Ni/Al-CSe compared to Ni/Al LDH can be explained by the presence of CS leaf extract (CS.
, which is rich in active groups, enabling it to act as an additional binding site that strengthens the interaction between the material surface and CEF molecules.
Figure 3.
Determination of point of zero charge .
Hpz.
of Ni/Al LDH and Ni/Al-CSe.
Effect of solution pH on the adsorption capacity of ceftriaxone using Ni/Al LDH and Ni/Al-CSe.
Figure 4.
The effect of time and adsorption kinetic modeling using PFO and PSO models for Ni/Al LDH and Ni/Al-CSe.
UVAeVis spectral changes of ceftriaxone during adsorption using .
Ni/Al LDH and .
Ni/Al-CSe at different contact times .
Ae70 mi.
Copyright A 2026.
ISSN 1978-2993 Bulletin of Chemical Reaction Engineering & Catalysis, 21 .
, 2026, 103 To understand the adsorption kinetics mechanism, the experimental data were analyzed using the pseudo-first-order (PFO) and pseudosecond-order (PSO) models, as shown in Table 1.
The PFO model yielded higher values of the coefficient of determination (R.
, namely 0.
(Ni/Al LDH) and 0.
994 (Ni/Al-CS.
, compared to the PSO, which were 0.
961 and 0.
Additionally, equilibrium adsorption capacity value .
) for PFO is also more consistent with the .
), 652A0.
296 mg.
g-1 (LDH) and 15.
517A0.
g-1 (CS.
, approaching the actual values of 317 mg/g and 14.
932 mg.
Based on the data, it can be concluded that the PFO model is more suitable for describing the adsorption kinetics of CEF on both materials.
This indicates that the adsorption process is controlled by a physical mechanism .
that is dominant in the initial stages, although the presence of active groups from the CS leaf extract on Ni/Al-CSe also contributes thru chemical interactions that strengthen the bond with ceftriaxone molecules.
Figure 4.
shows the changes in the UV-Vis spectrum of ceftriaxone (CEF) in the wavelength range of 200Ae300 nm during the adsorption process using Ni/Al LDH (Figure 4.
) and Ni/AlCSe (Figure 4.
Initially .
, the CEF solution showed high absorbance intensity with a main peak around 240 nm.
As the contact time increased, the absorbance intensity gradually decreased for both materials, indicating a reduction in CEF concentration due to the adsorption process.
In the Ni/Al LDH system (Figure 4.
), the absorbance decreased progressively until the 70th minute, resulting in a removal percentage of 79.
Meanwhile.
Ni/AlCSe (Figure 4.
) showed a more significant decrease in absorbance compared to Ni/Al LDH.
At the 70th minute, the removal efficiency reached This increase can be attributed to the presence of bioactive compounds in green tea leaf extract (Camellia sinensi.
, such as polyphenols and flavonoids, which enrich the surface functional groups.
The presence of these functional groups strengthens hydrogen bonds and increases the adsorbent's affinity for ceftriaxone molecules, while also increasing the effective surface area due to better particle These two results indicate that the adsorption process of ceftriaxone is rapid in the initial stage .
Ae20 minute.
, which suggests the dominance of surface interactions and the abundance of available active sites.
After that period, the rate of absorbance decrease slowed down, indicating that conditions close to equilibrium were reached due to a reduction in available active sites.
Figure 5.
shows the effect of adsorbent dosage variation on adsorption capacity .
, while Figure 5.
illustrates the removal efficiency (%) of ceftriaxone using Ni/Al LDH and Ni/Al-CSe In Figure 5.
, the adsorption capacity .
tends to decrease with increasing adsorbent At a dosage of 0.
01 g, the qe value reached 31 mg/g (Ni/Al LDH) and 95.
34 mg.
g-1 (Ni/AlCS.
However, when the dosage increased to 0.
g, the adsorption capacity decreased to 10.
g-1 (Ni/Al LDH) and 14.
44 mg.
g-1 (Ni/Al-CS.
This decrease is caused by an excess of active sites at high dosages, while the number of CEF molecules in the solution is limited.
Additionally, particle agglomeration at high adsorbent concentrations can reduce the effective surface area, thereby decreasing the adsorption capacity per gram .
Figure 5.
shows different trends for both For Ni/Al LDH, the removal efficiency increased up to an optimum dosage of 0.
04 g with a value of 79.
36%, then decreased at higher dosages, reaching 64.
83% at 0.
1 g.
This decrease can be explained by particle agglomeration and overlapping active sites, which reduce adsorption Conversely.
Ni/Al-CSe showed a more stable increasing trend in efficiency, from 28% .
86% .
This indicates that Ni/Al-CSe, with an increased adsorbent dosage, provides a greater total number of active sites, allowing more adsorbate molecules in the Table 1.
Kinetics parameters of CEF adsorption on Ni/Al LDH and Ni/Al-CSe.
Parameters Pseudo first order k1 .
Pseudo second order k2 .
Ni/Al LDH Ni/Al-CSe 0494A0.
652A0.
0341A0.
517A0.
00351A0.
250A0.
00168A0.
736A1.
Copyright A 2026.
ISSN 1978-2993 Bulletin of Chemical Reaction Engineering & Catalysis, 21 .
, 2026, 104 solution to bind, although the adsorption capacity per gram of adsorbent decreases.
These results indicate that the Ni/Al-CSe material has better performance compared to Ni/Al LDH in terms of both adsorption capacity and removal efficiency Ni/Al-CSe consistently showed higher adsorption capacity and greater removal efficiency across all adsorbent dosage variations, confirming that modification with CS leaf extract can improve the material's performance in the ceftriaxone adsorption process.
Table 2 presents the Langmuir and Freundlich isotherm parameters for the adsorption process of CEF using Ni/Al LDH and Ni/Al-CSe at a temperature of 303 K.
The analysis results show that the maximum adsorption capacity .
obtained from the Langmuir model significantly increased after the material was modified with green tea leaf extract.
The qmax value for Ni/Al LDH was recorded as 28.
g-1, while Ni/Al-CSe reached 111.
111 mg.
g-1, which is approximately four times higher.
This increased capacity indicates that the presence of bioactive compounds from CS extract, such as polyphenols and flavonoids, plays a role in enriching the surface active sites and enhancing the specific interaction between the adsorbent and antibiotic molecules.
Although both isotherm models were evaluated, the Langmuir model was applied to determine the maximum adsorption capacity .
, since this parameter is exclusively defined within the Langmuir framework and cannot be obtained from the Freundlich model.
The correlation coefficient (R.
indicates that the adsorption data for Ni/Al LDH is more consistent with the Freundlich model (R2 = 0.
compared to the Langmuir model (R2 = 0.
Similarly, for Ni/Al-CSe, the Freundlich model also provides a better fit (R2 = 0.
compared to the Langmuir model (R2 = 0.
Thus, the mechanism of ceftriaxone adsorption on the modified material more dominantly follows a multilayer adsorption pattern on a heterogeneous surface .
Additionally, the value of n obtained for Ni/Al-CSe .
is closer to 1 compared to Ni/Al LDH .
The value of n < 2 for both materials indicates that the adsorption process occurs with moderate to relatively weak spontaneously .
Additionally, the 1/n values for both materials are less than 1 .
< 1/n < .
, indicating that the CEF removal process is more Table 2.
Adsorption isotherm parameters of CEF using Ni/Al LDH and Ni/Al-CSe.
Materials T(AK) Ni/Al LDH Isoterm Langmuir qmax .
KL (L.
KL (L.
Ni/Al-CSe Parameters Isoterm Freundlich KF [.
(L.
KF [.
(L.
Figure 5.
Effect of adsorbent dosage on .
adsorption capacity .
removal efficiency (%) of ceftriaxone using Ni/Al LDH and Ni/Al-CSe.
Copyright A 2026.
ISSN 1978-2993 Bulletin of Chemical Reaction Engineering & Catalysis, 21 .
, 2026, 105 If the 1/n value is 1, it indicates no interaction between the adsorbate and adsorbent throughout the adsorption mechanism.
and if 1/n > 1, it indicates that the adsorption process is difficult to occur .
To evaluate the performance of the synthesized material, a comparison with other previously reported adsorbents is shown in Table 3.
The thermodynamic parameters presented in Table 4 provide further insight into the mechanism of CEF adsorption on Ni/Al LDH and Ni/Al-CSe.
The variation of Gibbs free energy change .
G) with temperature provides insight into the effect of thermal energy on adsorption As shown in Table 4, all iG values remain negative over the temperature range of 303Ae323 K, confirming that CEF adsorption on both Ni/Al LDH and Ni/Al-CSe proceeds spontaneously at all studied concentrations .
Ae 30 mg/L) .
For Ni/Al LDH, iG becomes more negative with increasing temperature at 15 and 30 mg/L, indicating enhanced spontaneity at higher temperatures, whereas at 20 and 25 mg/L the iG values gradually become less negative, suggesting a slight decrease in adsorption favorability upon heating.
A similar trend is observed for Ni/Al-CSe, where the iG values decrease with increasing temperature at 15 and 30 mg/L, but show a slight increase .
ess negative value.
at 20 and 25 mg/L.
Nevertheless, across all temperatures and concentrations.
Ni/Al-CSe consistently exhibits more negative iG values than Ni/Al LDH, demonstrating superior thermodynamic favorability and stronger affinity toward CEF.
The enthalpy changes .
H) reveal differences in adsorption mechanisms for both adsorbents depending on concentration.
For Ni/Al LDH, positive iH values are observed at 15 and 30 mg/L .
813 and 2.
517 kJ/mo.
, suggesting endothermic adsorption behavior, whereas negative iH values at 20 and 25 mg/L (-7.
685 and -2.
080 kJ/mo.
indicate an exothermic contribution under these In contrast.
Ni/Al-CSe displays predominantly negative iH values throughout the experimental concentration range (-1.
666 to 9.
490 kJ/mo.
, reflecting mainly exothermic adsorption processes.
This behavior implies that the incorporation of bioactive compounds from green tea leaf extract contributes to the formation of energetically favorable adsorption sites, thereby facilitating CEF immobilization on the modified surface.
Table 3.
Comparison of maximum adsorption capacities (Q.
of Ni/Al LDH and Ni/Al-CSe for ceftriaxone with other adsorbents reported in the literature.
Adsorbent Chitosan-GO-Zr Fe3O4-lignin Fe3O4-carbon-based lignin Powder activated carbon modified with magnetite nanoparticles (PAC-MNP.
C3N4/MWCNT/Bi2WO6 Spent coffee grounds NBent-NTiO2-Chit GO derived corn cob Pseudomonas putida biomass CuO nanosphere Ni/Al LDH Ni/Al-CSe Target Ceftriaxone Ceftriaxone Ceftriaxone Ceftriaxone Isotherm Langmuir Langmuir Freundlich Langmuir .
Ceftriaxone Ceftriaxone Ceftriaxone Ceftriaxone Ceftriaxone Ceftriaxone Ceftriaxone Ceftriaxone Langmuir Langmuir Langmuir Freundlich Freundlich Langmuir Freundlich Freundlich Reference .
This study This study Table 4.
Thermodynamic parameter values for CEF adsorption on Ni/Al LDH and Ni/Al-CSe.
Materials Ni/Al LDH Ni/Al-CSe Ni/Al LDH Ni/Al-CSe Ni/Al LDH Ni/Al-CSe Ni/Al LDH Ni/Al-CSe Concentration .
g/L) OIH .
J/mo.
OIS .
J/mol.
Copyright A 2026.
ISSN 1978-2993 OIG .
J/mo.
Bulletin of Chemical Reaction Engineering & Catalysis, 21 .
, 2026, 106 Entropy changes .
S) further clarify the physicochemical nature of adsorption.
For Ni/Al LDH, the iS values range from Oe0.
020 to 0.
kJ/mol.
K over the investigated concentration range .
Ae30 mg/L), indicating that the adsorption process may involve either slight increases or decreases in interfacial disorder depending on CEF concentration.
Similarly.
Ni/Al-CSe exhibits both positive and negative iS values (-0.
023 to 0.
026 kJ/mol.
K), reflecting concentration-dependent randomness at the solidAesolution interface.
Positive iS values suggest increased degrees of freedom of adsorbed species, whereas negative iS values imply the formation of a more ordered adsorption system due to stronger and more specific interactions between CEF molecules and the surface functional groups introduced by the green tea extract modification .
These thermodynamic features are consistent with the more negative iG values obtained for Ni/Al-CSe, confirming its superior adsorption affinity toward CEF.
The adsorbent's regeneration ability is one of the important parameters for assessing its application potential in sustainable waste Figure 6.
shows the results of the regeneration test of Ni/Al LDH and Ni/Al-CSe materials for CEF adsorption up to four reuse In the first cycle, both materials showed relatively high adsorption efficiency, namely 8% for Ni/Al LDH and 77.
03% for Ni/Al-CSe.
This indicates that modification with green tea leaf extract provides competitive initial performance compared to unmodified materials.
As the number of cycles increases, there is a decrease in adsorption efficiency for both However.
Ni/Al-CSe consistently showed better performance compared to Ni/Al LDH.
In the second cycle, the efficiency of Ni/AlCSe remained at 69.
98%, which was higher than Ni/Al LDH at 63.
Similar trends were observed in the third and fourth cycles, where Ni/Al-CSe recorded efficiencies of 64.
18% and 12%, respectively, while Ni/Al LDH only 75% and 46.
This difference in regeneration performance can be attributed to the presence of bioactive compounds from CS extract integrated into the LDH structure.
These compounds are believed to enhance surface stability and prevent the loss of most active sites during repeated adsorption processes.
Mechanism of Adsorption Figure 6.
shows the results of ceftriaxone (CEF) desorption tests from Ni/Al LDH and Ni/AlCSe materials using various reagents, namely distilled water (DW).
NaOH.
HCl, distilled water with ultrasound (DW US), and ethanol (EtOH).
This test is conducted to help explain the adsorption mechanism occurring between CEF and the material.
The results show that NaOH and HCl reagents provide the highest desorption When using NaOH, the desorption percentage reaches 88.
31% for Ni/Al LDH and 51% for Ni/Al-CSe.
This indicates that electrostatic interactions play an important role in the adsorption process.
When using HCl, the desorption values are even higher, namely 93.
(Ni/Al LDH) and 95.
71% (Ni/Al-CS.
However, observations indicate that the material undergoes structural damage under strong acidic conditions.
Thus, the high desorption in HCl not only reflects the release of CEF due to disruption of electrostatic interactions, but also due to the degradation of the LDH layer, which is inherently unstable in acidic conditions.
Therefore.
NaOH Figure 6.
Regeneration performance of Ni/Al LDH and Ni/Al-CSe for ceftriaxone adsorption and .
Desorption efficiency of ceftriaxone from Ni/Al LDH and Ni/Al-CSe using different reagents.
Copyright A 2026.
ISSN 1978-2993 Bulletin of Chemical Reaction Engineering & Catalysis, 21 .
, 2026, 107 representative in explaining the interaction mechanism between CEF and the adsorbent.
Other reagents showed lower desorption The use of DW and EtOH resulted in limited release, only 22.
94% and 66.
respectively for Ni/Al LDH, and 44.
52% and 40% for Ni/Al-CSe.
This indicates that neither hydrophobic interactions nor hydrogen bonds are the dominant mechanism in CEF adsorption.
Meanwhile, the use of DW with ultrasound (DW US) resulted in moderate desorption, 62% (Ni/Al LDH) and 28.
98% (Ni/AlCS.
Ultrasonic vibrations help release some of the weakly bound molecules on the surface, but they are not strong enough to break electrostatic These desorption results confirm that the main mechanism of CEF adsorption on both Ni/Al LDH and Ni/Al-CSe is primarily controlled by contributions from other surface interactions.
The fact that Ni/Al-CSe still exhibits high desorption values in NaOH without structural damage confirms that modification with CS extract not only enhances adsorption performance but also maintains material stability.
The FT-IR spectrum after CEF adsorption shown in Figure 7.
exhibits several significant The intensity of the -OH band at 3400 cm-1 decreases, indicating the involvement of hydroxyl groups in hydrogen interactions with CEF.
The shift and increase in intensity of the band around 1630-1700 cm-1 suggest the contribution of carbonyl (C=O) groups from CEF Additionally, the band around 1200-1300 cm-1 associated with CAeOAeC stretching undergoes intensity changes, confirming the presence of bonds between the ether/ester groups of CEF and the active sites of the adsorbent.
The metal- oxygen (M-O) bands located at <1000 cm-1 also experienced a slight shift after adsorption, indicating the possible occurrence of electrostatic interactions between the CEF anions and the cationic LDH layer.
Overall, these findings support the conclusion that the mechanism of CEF adsorption on Ni/Al-CSe occurs thru a combination of hydrogen bonding, electrostatic interactions, and the contribution of aromatic organic interactions (Aa-Aa stackin.
mediated by bioactive compounds from CS extract.
The possible mechanism of CEF adsorption that occurs can be seen in Figure 7.
Conclusions This research confirms that the biomodification of Ni/Al LDH with Camellia sinensis extract significantly enhances the adsorption performance of ceftriaxone.
The pH optimum shifted from 3 for Ni/Al LDH to 5 for Ni/Al-CSe, with the isotherm following the Freundlich model and the kinetics conforming to pseudo-first order.
The maximum adsorption capacity increased from 818 mg.
g-1 to 111.
111 mg.
g-1, indicating the significant role of bioactive groups in strengthening the interaction with CEF.
Thermodynamic spontaneously, while the more negative iG values and predominantly exothermic behavior of Ni/AlCSe confirm its superior thermodynamic favorability associated with more specific surface Regeneration tests prove that Ni/AlCSe is more stable than Ni/Al LDH for up to four Overall, these results confirm that biomodification with Camellia sinensis extract is an effective and sustainable strategy for addressing antibiotic pollution in aquatic environments.
Figure 7.
FTIR spectra of Ni/Al-CSe before and after CEF adsorption and .
Schematic diagram of the possible mechanism of CEF adsorption on Ni/Al-CSe.
Copyright A 2026.
ISSN 1978-2993 Bulletin of Chemical Reaction Engineering & Catalysis, 21 .
, 2026, 108 Acknowledgment .
Guan.
Li.
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Highly active Bi2O3/Co3O4 heterostructure peroxidasemimicking nanozyme for the sensitive detection of ceftriaxone sodium antibiotic.
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Phosphate-adsorbed metal organic framework as a recycled material for catalytic peroxymonosulfate activation.
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The authors would like to thank the Research Center of Inorganic Materials and Coordination Complexes.
Universitas Sriwijaya, for their support and facilities.
CRedit Author Statement Author Contributions:
Amri Amri:
Investigation.
Writing Ae Original draft.
Writing Ae review & editing.
Software.
Formal Analysis.
Najma Annuria Fithri: Data Curation.
Formal Analysis.
Validation.
Muhammad Said: Formal Analysis.
Validation.
Visualization.
Data Curation.
Aldes Lesbani:
Methodology.
Conceptualization.
Writing Ae review & editing.
Supervision.
Validation.
Visualization.
Data Curation.
All authors have read and agreed to the published version of the manuscript.
References