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No.
1, 2024
Chemistry Education Study Program.
Universitas Sebelas Maret https://jurnal.
id/jkpk ISSN 2503-4146 ISSN 2503-4154 .
FUNCTIONALIZATION MESOPOROUS SILICA USING AMINOPROPYLTRIETHOXYSILANE (APTES) AS ADSORBENT FOR REMOVAL Ni (II) FROM AQUEOUS SOLUTION Ega Hidayani1.
Andriayani2*.
Muhammad Taufik2 Postgraduate School.
Department of Chemistry.
Faculty of Mathematics and Natural Science.
University of Sumatera Utara.
Medan.
Indonesia.
Department of Chemistry.
Faculty of Mathematics and Natural Science.
University of Sumatera Utara.
Medan.
Indonesia.
ARTICLE INFO
ABSTRACT
Keywords:
Adsorption.
APTES,
Mesoporous Silica.
Nickel (II) This study successfully synthesized mesoporous silica using the template methyl ester ricinoleate (MS-TMR) and further functionalized the MS-TMR surface with 3-aminopropyltriethoxysilane (APTES).
The functionalization of MS-TMR with APTES was achieved through a 48hour grafting method.
For the adsorption experiments, 20 mg of both MS-TMR and MS-TMR-APTES adsorbents were employed to remove Article History:
Ni(II) from aqueous solutions at a concentration of 30 mg/L and pH 6.
Received: 2023-03-27 The objective was to assess the adsorption capacity and to characterize Accepted: 2024-02-26 the synthesized adsorbents.
Characterization was conducted using Published: 2024-03-03 Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Diffraction (XRD).
FTIR analysis revealed that the MS-TMR adsorbent possessed *Corresponding Author silanol (Si-OH) and siloxane (Si-O-S.
Conversely, the MSEmail: andriayani@gmail.
TMR-APTES adsorbent exhibited additional amine (N-H) and C-H doi:10.
20961/jkpk.
groups after the APTES grafting.
XRD results indicated that both samples were amorphous.
The concentration of Ni(II) ions was determined using Atomic Absorption Spectroscopy (AAS), which facilitated the calculation of removal percentages and adsorption MS-TMR achieved a mere 3.
54% removal of Ni(II) ions, corresponding to an adsorption capacity of 3.
21 mg/g.
In contrast.
MSTMR-APTES demonstrated significantly enhanced performance.
A 2024 The Authors.
This open- removing 54.
23% of Ni(II) ions with an adsorption capacity of 48.
access article is distributed mg/g.
The findings suggest that APTES-functionalized MS-TMR has under a (CC-BY-SA Licens.
considerable potential for removing Ni(II) ions and could be explored further for the adsorption of other heavy metal ions.
How to cite: E.
Hidayani.
Andriayani.
Taufik, " Functionalization Mesoporous Silica using Aminopropyltriethoxysilane (APTES) as Adsorbent for Removal Ni (II) from Aqueous Solution," Jurnal Kimia dan Pendidikan Kimia (JKPK), vol.
9, no.
1, pp.
115-129, 2024.
Available:
http://dx.
org/10.
20961/jkpk.
industrial waste include nickel (N.
, zinc (Z.
INTRODUCTION The increasing pace of industrial copper (C.
, chromium (C.
, cadmium (C.
, development may contribute significantly to lead (P.
, mercury (H.
, and arsenic (A.
water pollution through industrial wastewater Nickel is notably carcinogenic and can cause a range of health issues, including digestive organic and inorganic pollutants, includes disorders, lung and kidney problems, and skin dermatitis .
A 2022 study highlighted the .
Industrial waste, hazardous due to their non-biodegradable Commonly found heavy metals in exposure on workers in a nickel refining factory, showing that long-term exposure to Hidayani et al.
Functionalization Mesoporous Silica .
nickel dust and fumes significantly increases capacity of 103.
10 mg/g for Cd2 ions and the risk of developing respiratory diseases 03 mg/g for Cu2 ions .
, .
However, such as bronchitis, asthma, and lung cancer the efficiency in removing other heavy metal .
These health risks underscore the urgent need for effective mitigation strategies to Mesoporous silica's lack of diverse functional safeguard workers in nickel-related industries groups on its surface restricts its application to and the general public from the adverse specific target molecules.
effects of nickel pollution.
Nickel is primarily sourced from mining, mesoporous silica's surface can be modified smelting, machinery processing, chemical with various ligands such as organic groups, production, textiles, and electroplating.
The coordination compounds, and nanoparticles to electroplating industry, in particular, utilizes expand its application scope .
A common substantial quantities of nickel in its coatings strategy for enhancing adsorbent properties and discharges nickel-rich effluents with concentrations reaching up to 500 mg/L .
, far Specifically, amine group modification is exceeding the safe limit of 1 mg/L for nickel advantageous due to the simplicity of the reaction and its effectiveness in heavy metal threshold poses significant environmental and removal .
Functionalizing mesoporous public health risks due to water pollution .
silica with amine groups allows it to bind Exceeding The conventional method for Ni(II) .
several divalent cations, thus exhibiting high adsorption capacity and selectivity for heavy however, this treatment is costly and often fails metal ions.
The silane coupling agent 3- to reduce the residual Ni(II) concentration in Aminopropyltriethoxysilane the effluent to safe levels .
The adsorption characterized by its amine groups, plays a technique provides a superior alternative for crucial role in this process .
heavy metal ion removal due to its versatility, (APTES).
The functionalization of mesoporous silica with APTES results in silane termination simplicity, cost-effectiveness, and the potential within the structure, creating a stable covalent for adsorbent regeneration .
Among various bond between the amine group of APTES and adsorbents, mesoporous silica stands out due the silanol group on the silica mesopore to its high surface area, uniform pore size surface .
This chemical modification distribution, low production cost, substantial significantly increases the surface area and adsorption capacity for pollutants, and the pore volume, maximizing the contact area ease with which its surface can be chemically between the adsorbent and the heavy metal modified to enhance performance .
Consequently.
Ni(II) ions in the solution Previous research has documented form coordination complexes with the amine the synthesis of mesoporous silica using APTES- methyl ester ricinoleate with added HCl as an functionalized mesoporous silica through adsorbent, achieving a maximum adsorption chelation .
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Extensive APTES-functionalized mesoporous silica for various applications, such as the adsorption of Pb(II).
Cu(II), and Cd(II) ions .
, textile dye adsorption .
, and CO2/H2O adsorption .
However, despite these advancements, studies focusing on Ni(II) adsorption are relatively scarce.
This study aims to fill this gap by exploring the APTES- functionalized mesoporous silica for Ni(II) technique and providing crucial data that can aid in the development of effective and Mesoporous silica synthesized using ricinoleate methyl ester from castor oil (Ricinus communi.
as a template will be functionalized with APTES using the postsynthesis grafting method to integrate amine groups onto the silica mesopore surface.
The Synthesis of Methyl Ester Ricinoleate from Castor Oil The methyl ester synthesis from castor oil (Ricinus communi.
was following established protocols .
The process involved transesterification, where 40 grams of castor oil, 86 grams of methanol, 8 grams of KOH as a catalyst were combined in a three-neck flask.
This mixture was refluxed at 70AC for four hours.
Subsequently, the reaction mixture was extracted with n-hexane, resulting in two The upper phase was washed with distilled water, and the methyl ester was isolated using a rotary evaporator, yielding a pale yellow-colored product.
The product's Gas Chromatography-Mass Spectrometry (GCMS).
The prepared methyl ester served as a template for synthesizing mesoporous silica.
silica will be applied as an adsorbent for Ni(II) Synthesis of Mesoporous Silica MSTMR The ions in aqueous solutions.
resulting APTES-functionalized mesoporous literature, involved the optimization of TEOS
METHODS
and APMS concentrations .
, methanol Materials The materials employed in this study include castor oil, distilled water, methanol (CH3OH), potassium hydroxide (KOH), nhexane (TEOS), (C6H.
, 3-aminopropyltrimethoxysilane (APMS), deionized water, hydrochloric acid (HC.
, toluene, 3-aminopropyltriethoxysilane (APTES), ethanol (C2H5OH), and nickel nitrate hexahydrate (Ni(NO.
6H2O).
These materials were utilized due to their high purity levels, suitable for the chemical processes mass .
, and HCl volume .
Initially, 9.
g of methyl ester ricinoleate was mixed with 150 mL of deionized water, 15 mL of methanol, and 50 mL of 0.
1 M HCl and stirred for 30 minutes .
ixture A).
Concurrently, 064 g of TEOS .
058 mo.
of APMS .
0116 mo.
were combined and stirred for 15 minutes in a sealed container .
ixture B).
Mixture B was then added to mixture A, and the combined mixture was stirred for an additional 2 hours.
The reaction mixture was aged in an oven at 80AC for 72 hours to allow the formation of porous solids.
Hidayani et al.
Functionalization Mesoporous Silica .
Post-aging, the mixture was centrifuged, the Philip 3050/XPert Pro PANalytical solid washed with deionized water, and dried system, utilizing Cu K radiation ( = 1.
542 yI) at 60AC.
The final product was calcined at with scans at a speed of 2 deg/min over a 550AC for 6 hours to obtain a white solid, range of 2 = 1-15A for low angles and 2 = designated as MS-TMR .
10-90A for wide angles, to assess the crystalline structure of the mesoporous silica.
Functionalization of Mesoporous Silica with APTES The mesoporous silica MS-TMR was 3(APTES) following a modified post-grafting method referenced from the literature .
The process involved placing 1 gram of MS-TMR and 100 mL of dry toluene into a three-neck flask, stirring for 30 minutes.
Afterward, 5 mL of APTES was added, and the mixture was refluxed at room temperature under a nitrogen atmosphere for 48 hours.
The product was then filtered and washed sequentially with 50 mL of dry toluene and 50 mL of ethanol, followed by drying under vacuum at 80EE for 20 hours.
Ni (II) Adsorption In separate trials, the adsorption study for Ni(II) ions was conducted using 20 mg of MSTMR and MS-TMR-APTES as adsorbents.
Each adsorbent was placed in a 250 mL Erlenmeyer flask containing a Ni(NO.
6H2O
solution at 30 mg/L concentration.
The flask was shaken at 150 rpm for one hour at room Subsequently, the reaction mixture was filtered, and the filtrate was Atomic Absorption Spectroscopy (AAS, iCE 3.
The AAS was equipped with a hollow cathode lamp specific to Ni(II), and the Ni(II) absorption was measured at a wavelength of 232.
2 nm.
Calibration curves derived from standard solutions of known Ni(II) concentrations were Characterization Characterization of the synthesized utilized to ensure precise quantification of the materials was performed using several residual Ni(II) ions not adsorbed by the silica.
Gas Chromatography-Mass Spectrometry (GC-MS) analysis was carried out on a Trace 1310 GC system with a Data analysis The capillary fused silica column, with the mesoporous silica adsorbent was calculated temperature settings ranging from 140AC to using the following equation:
220AC and helium as the carrier gas flowing at 40 to 70 mL/min.
Fourier-transform Infrared Spectroscopy (FT-IR) conducted using a Shimadzu IR Prestige-21 instrument with KBr pellets to identify functional groups on the castor oil methyl aycuOeyayc.
The percentage removal of Ni (II) metal by mesoporous silica adsorbent was calculated using the following equation:
aycuOeyayc.
yaycu y 100 % .
esters and silica mesopore surfaces.
X-ray Where.
C0 .
g/L) is the initial concentration Diffraction (XRD) was executed using an E of nickel (II) metal.
Ce .
g/L) is the final JKPK (JURNAL KIMIA DAN PENDIDIKAN KIMIA).
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concentration of Ni (II) metal.
Adsorption methyl ester content was determined to be capacity (Q.
is the amount of Ni (II) metal adsorbed per mass of mesoporous silica comprising methyl esters of other fatty acids.
V is the volume of solution (L), and m This aligns with previous findings indicating is the mass of mesoporous silica .
, .
RESULTS AND DISCUSSION
constituting nearly 90% of its composition Synthesis and Characterization of Castor Oil Methyl Ester Castor oil was chosen as the template for .
The use of high-purity materials is crucial as they are likely to yield methyl esters this study due to its wide availability and of superior quality, which in turn could abundant raw material properties, making it a enhance their adsorption capacity, stability, cost-effective option for biodiesel production.
and performance across various applications Unlike other vegetable oils, castor oil is .
unique in that it is the sole source of The high purity of castor oil methyl hydroxylated fatty acids, which are crucial for ester ensures the uniformity of the template producing higher yields of methyl esters structure necessary for forming mesoporous during the transesterification process .
this reaction, castor oil is transesterified using morphology .
The direct correlation popular alcohols such as methanol and between the purity of castor oil methyl ester ethanol, which are the most commonly and the quality and performance of the utilized .
synthesized mesoporous silica is pivotal.
The conversion of castor oil into fatty especially when modified with APTES.
acid methyl esters and other compounds was Ensuring the silica surface is devoid of quantified using Gas Chromatography-Mass contaminants is essential for facilitating a Spectrometry (GC-MS).
According to the robust bond between the silica matrix and the results presented in Table 1, the ricinoleate APTES functionalization process .
Table 1.
GCAeMS analysis for the methyl ester synthesized from castor oil (Ricinus communi.
Retention time .
The Name Hexadecanoic acid, methyl ester 9,12-Octadecadienoic acid (Z.
Z)-, methyl ester
9-Octadecenoic acid (Z)-, methyl ester
9-Octadecenoic acid (Z)-, methyl ester
Octadecanoic acid, methyl ester
Methyl ricinoleate Fourier
Molecular
Area
(%)
Infrared indicative of its molecular structure.
Spectroscopy (FT-IR) spectrum of castor oil absorption band at 3700 cm-1 signifies the methyl ester, displayed in Figure 1, reveals presence of hydroxyl (OH) groups.
The bands observed at 2922 cm-1 and 2855 cm-1
Transform
Molecular
Formula
C17H34O2
C19H34O2
C19H36O2
C19H36O2
C19H38O2
C19H36O3
Hidayani et al.
Functionalization Mesoporous Silica .
correspond to sp3 hybridized C-H stretching These hydroxyl groups in the castor vibrations, typical of alkyl chains.
Notably, the oil methyl esters are particularly significant as absorption at 1744 cm-1 is attributed to the they provide potential sites for hydrogen bonding with silica precursors during the (C=O), component of the methyl ester structure .
Additional bands at 1438 cm-1 and Such hydrogen bonds facilitate the condensation 1364 cm-1 indicate alkane groups (C-C) present in mono-, di-, and triglyceride glycerol thereby aiding in creating organic-inorganic structures within the methyl esters of castor hybrid materials .
The results from both oil biodiesel.
The ether functionalities are GC-MS and FT-IR analyses confirm the represented by bands at 1170 cm and 1013 suitability of castor oil methyl ester as a cm , associated with C-O and C-O-C template for synthesizing mesoporous silica.
stretching vibrations, respectively.
The band The role of the methyl ester as a surfactant is suggests the presence of a phenyl ring at 857 it acts as a template and significantly cm , and the characteristic absorption at 723 influences the pore size in the resultant silica cm-1 is due to methylene groups (CH.
Figure 1.
Spectra FT-IR analysis of castor oil methyl ester Characterization of Adsorbent heats the reaction mixture to its boiling point and condenses the vapors back into the The functionalization of mesoporous silica with APTES was done through a grafting method involving a 48-hour reflux process in an inert atmosphere.
This method reaction vessel, ensuring continuous mixing and homogeneous distribution of reactants.
Such conditions are critical for effective grafting, as they maintain optimal reaction JKPK (JURNAL KIMIA DAN PENDIDIKAN KIMIA).
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relates to the vibrations of the C-H group of Toluene, chosen for its non-polar properties the APTES propyl chain and the N-H group and ability to dissolve various organic vibrations at 1565 cm-1, with the C-N bond at compounds, promotes homogeneous mixing 1379 cm-1 confirming successful APTES with inorganic substrates.
The solvent must grafting .
, .
be dry to avoid the clustering of silanol groups Adding amine groups via APTES on the mesoporous silica surface, as even enhances the adsorption surface area.
minimal amounts of water can trigger this improves the selectivity of the adsorbent issue .
The tri alkoxysilane groups in towards Ni(II) ions, facilitating the formation APTES react with the silica network's silanol of stable chelation complexes with metal groups through alkoxy-silanol interactions.
ions, thus increasing adsorption efficiency Successful .
evidenced by the appearance of C-H and N- Figure XRD H groups in the FT-IR analysis, indicating that diffractograms of both MS-TMR and MS- the amine groups on the silica surface are TMR-APTES.
ready to interact with target molecules.
The broadened peak at 2 around 22A, and the presence or absence of water during the absence of sharp peaks suggests the process influences the distribution and maintenance of an amorphous structure, density of functional groups on the silica which is crucial for effective adsorption due to surface due to the potential hydrolysis of the higher surface area and stability provided APTES, by amorphous structures .
, .
Introducing reactions and the formation of silanol groups amine groups from APTES modifies the silica .
The Figure 2 displays the FT-IR spectra of evidenced by new diffraction peaks or MS-TMR .
and MS-TMR-APTES .
changes in peak intensity, demonstrating MS-TMR shows an absorption band at 3448 successful functionalization .
cm for hydroxyl groups and a 470 cm band Preserving the amorphous structure for the Si-O-Si bond.
Absorption bands at post-APTES 1110 and 802 cm-1 correspond to asymmetric Si-O-Si.
MS-TMR-APTES typically exhibit superior adsorption kinetics spectrum, the disappearance of the 979 cm-1 band post-grafting indicates that the Si-OH However, the synthesis techniques required groups have been converted to Si-O groups to maintain this structure can be more with amine attachments.
The presence of complex and costly than those producing absorption bands at 2924 and 2854 cm crystalline materials .
Hidayani et al.
Functionalization Mesoporous Silica .
Figure 2.
Spectra FT-IR analysis of MS-TMR and MS-TMR-APTES Figure 3.
Diffractogram XRD analysis of MS-TMR and MS-TMR-APTES Adsorption Ni (II) Solution Adsorption APTES adsorbents, with results detailed in conducted using MS-TMR and MS-TMR- Table 2 and Figure 4.
The MS-TMR adsorbent achieved a removal efficiency of 54% for Ni (II) metal ions from an aqueous JKPK (JURNAL KIMIA DAN PENDIDIKAN KIMIA).
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solution, corresponding to an adsorption availability and cost-effectiveness of APTES capacity of 3.
21 mg/g.
In contrast, the MS- reagents and the scalability of the synthesis TMR-APTES process for large-scale applications, also improved performance, removing 54.
23% of Ni (II) metal ions with an adsorption capacity 81 mg/g.
The enhanced adsorption need consideration .
, .
Table 2.
Adsorption of Ni (II) by adsorbent Adsorbent efficiency of MS-TMR-APTES is attributed to the amine groups (-NH.
introduced through APTES grafting on the silica surface, which MS-TMR
MS-TMRAPTES
g/L) .
g/L) 28,93 13,73 .
3,21 48,81 (%) 3,54 54,23 facilitates more effective adsorption than MSTMR.
This improvement aligns with the principles of the Hard Soft Acid Base (HSAB) theory, which suggests that mesoporous silica modified with amine groups, being hard bases, effectively binds the borderline acid nature of Ni (II) metal ions .
The amine groups engage in complex formation with target molecules through Lewis acid-base The Figure 4.
%Removal Ni (II) by Adsorbent enhance electrostatic interactions, attracting negatively charged ions.
While MS-TMR mechanisms such as Van der Waals forces.
MS-TMR-APTES The strong binding affinity of the amine groups to Ni (II) ions results from the formation of stable coordination complexes.
However, the affinity of amine groups to other heavy metals may vary based on factors such additional chemical interactions, including as charge, size, and metal coordination complexation and electrostatic interactions, preferences, affecting the selectivity of MS- due to the presence of amine groups .
TMR-APTES for different heavy metal ions However, the solution's maximum from industrial waste.
Metals with higher adsorption capacity is influenced by surface charges or larger ionic radii are likely to form area, pore size, and adsorbate concentration.
stronger complexes with amine groups than Although those with lower charges or smaller ones MS-TMR-APTES increased adsorption capacity for nickel, a .
saturation point exists beyond which further Additional comparative data on Ni (II) functionalization or surface modification does adsorption using various adsorbents are not significantly enhance the adsorption provided in Table 3, illustrating a broader Practical limitations, such as the context for the effectiveness of different adsorption technologies.
Hidayani et al.
Functionalization Mesoporous Silica .
Table 3.
Comparison of adsorption capacities Ni (II) with other adsorbent Adsorbent
199,19 32,10 167,55 3,21 48,81 Composite material Nano-SZO
MCA
MS-TMR
MS-TMR-APTES
Ref.
adsorbent significantly enhanced the removal efficiency to 54.
23% and the adsorption capacity to 48.
81 mg/g.
These findings .
This Study This Study mesoporous silica with APTES improves the adsorption efficiency for Ni(II) metal ions and indicates the potential of MS-TMR-APTES to effectively adsorb other heavy metal ions.
This CONCLUSION enhancement is attributed to the increased The synthesis of mesoporous silica interaction capabilities afforded by the amine using a methyl ester ricinoleate template (MS- TMR) and its subsequent functionalization functionalization, which facilitate stronger with 3-aminopropyltriethoxysilane (APTES), binding with metal ions.
MS-TMR-APTES,
APTES
successfully conducted.
Both samples were ACKNOWLEDGMENT Transform This research is financially supported by Infrared Spectroscopy (FTIR) and X-ray the Directorate of Research.
Technology, and Diffraction (XRD).
FTIR analysis of MS-TMR Community Service of the Ministry of revealed the presence of Si-OH and Si-O-Si Education, groups, indicative of the silica structure.
Technology (DRTPM KEMDIKBUDRISTEK) Following the functionalization with APTES, the appearance of C-H.
N-H, and C-N groups 79/UN5.
1/PPM/KP-DRTPM/B/2023 .
Fourier Culture.
Contract Research.
Number in the FTIR spectra confirmed the successful grafting of APTES onto the MS-TMR surface.
XRD analysis further corroborated that both products maintained an amorphous structure.
MS-TMR
MS-TMR-APTES
evaluated as adsorbents for removing Ni(II) metal ions from an aqueous solution.
The experimental conditions were set at a Ni(II) concentration of 30 mg/L, a pH of 6, a contact
REFERENCES