Buscar en
Boletín de la Sociedad Española de Cerámica y Vidrio
Toda la web
Inicio Boletín de la Sociedad Española de Cerámica y Vidrio Synthesis and characterization of amorphous mesoporous silica from palm kernel s...
Journal Information
Vol. 59. Issue 4.
Pages 159-164 (July - August 2020)
Share
Share
Download PDF
More article options
Visits
691
Vol. 59. Issue 4.
Pages 159-164 (July - August 2020)
Original
DOI: 10.1016/j.bsecv.2019.09.006
Open Access
Synthesis and characterization of amorphous mesoporous silica from palm kernel shell ash
Síntesis y caracterización de la sílice mesoporosa amorfa a partir de la cáscara del núcleo de palma
Visits
...
Patrick E. Imoisili
Corresponding author
patrickehis2002@yahoo.com

Corresponding author.
, Kingsley O. Ukoba
Corresponding author
ukobaking@yahoo.com

Corresponding author.
, Tien-Chien Jen
University of Johannesburg, Johannesburg, South Africa
Article information
Abstract
Full Text
Bibliography
Download PDF
Statistics
Figures (7)
Show moreShow less
Tables (1)
Table 1. The chemical composition of raw husk, PKSA and extracted silica in percentage.
Abstract

This study synthesized and characterized amorphous mesoporous silica from palm kernel shell ash. Sol–gel synthesis technique was used to produce the amorphous mesoporous silica from palm kernel shell ash. Silica is an affordable material with numerous applications including glass production, electronics and polymer materials, drug delivery and energy storage. It has been manufactured from different agricultural bio-resources with limited research on palm kernel shell ash (PKSA). The synthesized amorphous mesoporous silica was characterized using X-ray fluorescence (XRF), X-ray diffraction (XRD), Fourier transform infrared (FTIR) techniques, scanning electron microscope (SEM) and energy dispersive X-ray (EDX). The XRD patterns reveal the amorphous nature of the extracted amorphous silica, EDX confirmed the presence of SiO2, while FTIR analysis shows the existence of silanol and siloxane groups. Thermal gravimetric analysis (TGA) indicate presence of physically adsorbed and chemically bound water. Silica yield after synthesis was 96.83%. This success means decreases in environmental contamination caused by indiscriminate disposal of palm kernel shell (PKS) and amorphous silica for advanced material applications including glass and ceramics, drug delivery.

Keywords:
Waste
Palm kernel shell
Powder
Silica
Sol–gel processes
Glass
Resumen

Este estudio sintetizó y caracterizó la sílice mesoporosa amorfa a partir de la cáscara del núcleo de palma. Se usó la técnica de síntesis de sol-gel para producir la sílice mesoporosa amorfa de la cáscara del núcleo de palma. La sílice es un material asequible con numerosas aplicaciones que incluyen la producción de vidrio, electrónica y materiales de polímeros, la administración de medicamentos y el almacenamiento de energía. Se ha fabricado a partir de diferentes recursos biológicos agrícolas, con una investigación limitada sobre la cáscara del núcleo de palma (PKSA). La sílice mesoporosa amorfa sintetizada se caracterizó utilizando técnicas de fluorescencia de rayos X (XRF), difracción de rayos X (XRD), técnica de infrarrojos por transformada de Fourier (FTIR), microscopio electrónico de barrido (SEM) y rayos X de energía dispersiva (EDX). Los patrones de XRD revelan la naturaleza amorfa de la sílice mesoporosa amorfa extraída, EDX confirmó la presencia de SiO2, mientras que el análisis FTIR muestra la existencia de grupos de silanol y siloxano. El análisis gravimétrico térmico (TGA) indica la presencia de agua adsorbida físicamente y unida químicamente. El rendimiento de sílice después de la síntesis fue del 96.83%. Este éxito significa una disminución de la contaminación ambiental causada por la eliminación indiscriminada de la envoltura del núcleo de palma (PKS) y la sílice mesoporosa amorfa para aplicaciones avanzadas de materiales que incluyen vidrio y cerámica, suministro de medicamentos.

Palabras clave:
Residuos
Cáscara del núcleo de palma
Polvo
Sílice
Procesos sol–gel
Vaso
Full Text
Introduction

The need to manage waste and reduce environmental pollution has led to wastes being employed as substitute to traditional materials [1]. Palm kernel is useful plant but some parts constitute agricultural wastes. Palm kernel commonly known as Elaeis guineensis from the palm oil trees are found in enormous quantity in Asia and Africa, especially in Nigeria [2]. They are the stiff endocarp of palm fruit that borders the seed and is alternatively recognized as oil palm shell [3]. Pam kernel shell (PKS) is gotten as a remaining superfluous in the removal of the seed in the nut once palm oil has been extracted from the mesocarp of palm oil pod [4]. Many researchers and scientists have used PKS to substitute conventional normal weight aggregates (NWA) as lightweight aggregates (LWA) in motorway construction, essential elements and other applications ranging from biomass, energy storage, bio-fertilizer, to super-capacitor electrode [5–11].

Silica gels are a stiff three-dimensional linkage of colloidal silica. Amorphous mesoporous silica gels are categorized based on the synthesis process as an aqua gel, xerogel and aerogel. Amorphous mesoporous silica [12] has been effectively extracted from several agrarian bio-resources such as sugar-cane [13–16], rice husk ash [17–21], corn cob ash [22–26], bagasse ash [27], clay [28], coffee husk ash and wheat husk ash [29–31]. Techniques such as sol–gel, gasification and acid leaching [26–33] have been investigated to produce pure amorphous silica.

This study produced amorphous mesoporous silica from agricultural bio-resources of PKSA via the sol–gel method. It has a combined advantage of reducing disposal as well as pollution problems and making valued amorphous silica at lesser cost. The sol–gel method in comparison with other extraction methods has higher silica yield, low energy consumption and densification at lower temperature [17–33]. PKSA as a source of silica has higher net calorific value (LHV), indicating large energy value and higher ash content compared to other biomass like coconut shell, wheat husk and rice husk [31–33]. The prepared amorphous mesoporous silica from palm kernel shell ash (PKSA) have been characterized by means of XRD, XRF, SEM/EDX, FTIR and TGA techniques.

Materials and methodsSilica synthesis

Fig. 1 shows the PKS collected from South West Nigeria, washed and dried in open air. Combustion of PKS was done for 3h at 750°C with a heating speed of 10°C/min and allows cooling in the muffle furnace. Amorphous silica was extracted from the PKSA, shown in Fig. 2, using the sol–gel technique as hitherto reported by Okoronkwo et al. [25]. About 200ml ratio of 2N NaOH was added to 50g PKSA samples and heated for 2h using a hot plate with continuous stirring to dissolve the silica present in the ash and produce a silicate solution. Ashless filter paper was used to filter the solutions and 100ml boiled distilled water was used to wash the residue. After cooling, the filtrate was titrated with 2N HCl to pH in the range of 7.5–8.5 with continual stirring and nurtured for 24h to allow gel development. The gel was softly broken after ageing and centrifuged for 4min at 4000rpm. While the supernatant was castoff, the aqua gels were placed inside an oven to dry at 80°C for 24h to yield, silica xerogels.

Fig. 1.

Palm kernel shell.

(0.1MB).
Fig. 2.

Palm kernel shell ash (PKSA).

(0.06MB).
Moisture content of silica gels

The silica gels moisture content was determined using an air oven technique [34]. 1g of extracted silica was heated in aluminium humidity pans at 110°C for 1h. The samples were thereafter cool in a desiccator and weighed. Percentage (%) weight loss was recorded as the moisture content of extracted silica.

Characterization

XRD of PKSA and extracted silica was scanned using GBC EMMA X-Ray diffractometer having Cu Kα emission at 25kV acceleration voltage and 400μA current from 2θ 15° to 55° at a speed of 4.00°/min. The quantitative investigation of chemical constituents of PKSA and silica extract was carried out by means of X-ray fluorescence (XRF) Phillip Magix Pro XRF instruments. Morphology was observed with a SEM (Zeiss Ultra Plus) and EDX at secondary electron image (SEI) and high vacuum (HV) mode with 20kV accelerating voltage. FTIR spectra were recorded using Tianjin GangDong FTIR 650 in the range of 4000–450cm−1. A small quantity of sample (1wt.%) was scrupulously mixed with ground KBr in an agate mortar and a disc was prepared in vacuum maintaining a pressure of 33kg/cm2. The spectrogram of the sample is observed on computer monitor and a graphic representation of the spectra was taken. Thermal gravimetric analysis (TGA) was evaluated using Perkin-Elmer Pyris 6 TGA analyzer. Approximately 10mg weight was heated from 30 to 1000°C with a heating rate of 5°C/min in nitrogen atmosphere.

Results and discussions

The extracted silica content of washed xerogel was 54.35% and percentage moisture was 2.68%.

Structural properties

The XRD pattern of PKSA and extracted amorphous silica are shown in Fig. 3. The XRD pattern for the ash shows the present quartz at theta=24, and 43° (SiO2 PDF Card #331161). The broad XRD array of extracted silica at theta=22.5° shown in Fig. 4. The observed pattern is distinctive of amorphous solid, thereby confirming the formation of amorphous silica phase identification of this peak gave hexagonal symmetry of quartz silica [JCPDS value (47–1144)]. This is in concordance with similar XRD patterns of amorphous silica obtained from corn [22–26].

Fig. 3.

XRD of palm kernel shell ash and extracted amorphous silica.

(0.1MB).
Fig. 4.

FTIR spectra of silica from PKSA.

(0.08MB).
Chemical properties

FTIR spectral identified the key chemical compound existing in the silica as revealed in Fig. 4. Band 770–795cm−1 (Al–Mg–OH) (free silica and or quartz admixtures) and 740–755cm−1 (Si–O–Al) was assigned to symmetric stretching vibration network of gel network [35–37]. Band 1050–1170cm−1 was owed to symmetric stretching vibration network of Si–O–Si [38] and broad band at 1633–1645cm−1 and 3390–3445cm−1 is due to O–H bending and stretching vibration from Si–OH silanol groups and are owing to adsorbed H2O molecules on the samples surface [39,17].

Morphological and elemental analysis

Fig. 5a and b shows the SEM micrographs of the silica extracted from PKSA respectively. Fig. 4a shows the surface texture and morphology of the amorphous silica extracted from the PKSA with silica–silica agglomeration. The micrograph is observed to have agglomeration of silica with irregular particle shapes, which varies in sizes and are widely distributed. EDX spectral shows strong intensity of Si and O, which confirms silica (SiO2) as the predominant element in the sample. The presence of other elements such as Na, K is a result of the substrate used for the SEM/EDX analysis.

Fig. 5.

(a) SEM and (b) EDX micrograph of the silica from PKSA.

(0.48MB).

Table 1 shows the elemental composition of PKSA and extracted silica in percentage. The highest quantity of elements present in the ash was silicon dioxide (SiO2, 56.76%) which is similar to other customary siliceous pozzolans (e.g. corn cob ash or rice husk ash). The occurrence of calcium oxide is noticeable (CaO, 12.57%). Potassium (expressed as K2O, 9.19%) which is an essential plant nutrient is the third element by percentage and is characteristic of several biomass ashes [40]. Also present are other important compounds, such as Al2O3, Fe2O3, MgO, SO3, and P2O5. High value of these compounds might be due to the soil content and type of fertilizer used, which differs from location to location. Silica yield after synthesis was 96.83% with minor mineral content as impurities. These impurities; might be owed to entrapment of metal ions in the samples, which might not have been filtered out by washing [25].

Table 1.

The chemical composition of raw husk, PKSA and extracted silica in percentage.

Oxides  Raw husk  Before synthesis  After synthesis 
Organic matter  42.21  –  – 
SiO2  13.65  56.76  96.83 
Al2O3  9.18  8.58  0.0 
Fe2O3  1.81  0.91  0.17 
CaO  13.21  12.57  0.43 
MgO  6.54  5.45  0.17 
SO3  0.84  0.71  0.0 
P2O5  4.37  4.21  0.0 
K26.48  9.19  1.43 
Na21.71  1.62  0.97 

Fig. 6 shows the pictorial representation of the extracted amorphous mesoporous silica from palm kernel shell ash using the sol–gel technique.

Fig. 6.

The extracted amorphous mesoporous silica.

(0.03MB).
Thermal analysis

The results of thermal gravimetric analysis (TGA) are shown by Fig. 6. Two step weight losses were observed. The physically adsorbed water was attributed to the weight loss up to 150°C (TGA step 1), while chemically bound water from the sol–gel production method was attributed to the weight loss from 150 to 600°C [41,42]. Above 600°C, no further weight loss was observed indicating thermal stability of extracted mesoporous silica (Fig. 7).

Fig. 7.

TGA of silica from PKSA.

(0.05MB).
Conclusion

This work has shown that 56.65% amorphous silica yield, 2.68% moisture and negligible inorganic impurities can be produced from palm kernel shell ash using the sol–gel technique. XRD investigation has revealed the presence of silica in the ash and amorphous nature of extracted silica. SiO2 presence in the samples was established by EDX result. Agglomeration of silica–silica of varied sizes and shapes was observed from the SEM analysis. Key chemical groups existing in the samples were indicated by FTIR data. FTIR analysis shows the existence of silanol and siloxane groups. An after synthesis yield of 96.83% silica was obtained. Thermal gravimetric analysis (TGA) indicate thermal stable mesoporous silica with presence of physically adsorbed and chemically bound water. This result will help in combating the environmental nuisance of palm kernel shell by converting it into useful product. It will also be a cheap source of silica as an industrial raw material for drug delivery, glass production.

Conflict of interest

None declared.

Acknowledgments

Authors would like to acknowledge the financial support from NRF of South Africa and the PDRF support from the University of Johannesburg.

References
[1]
S.S. Owoeye, T.S. Toludare, O.E. Isinkaye, K. Ukoba.
Influence of waste glasses on the physico-mechanical behavior of porcelain ceramics.
Bol. Soc. Esp. Cerám. Vidr., 58 (2019), pp. 77-84
[2]
R. Mortimer, S. Saj, C. David.
Supporting and regulating ecosystem services in cacao agroforestry systems.
Agrofor. Syst., 92 (2018), pp. 1639-1657
[3]
O.M. Ikumapayi, E.T. Akinlabi.
Composition, characteristics and socioeconomic benefits of palm kernel shell exploitation – an overview.
J. Environ. Sci. Technol., 11 (2018), pp. 220-232
[4]
K.E. Anyaoha, R. Sakrabani, K. Patchigolla, A.M. Mouazen.
Critical evaluation of oil palm fresh fruit bunch solid wastes as soil amendments: prospects and challenges.
Resour. Conserv. Recycl., 136 (2018), pp. 399-409
[5]
Fiber and palm kernel shell in various applications.
Sustainable Technologies for the Management of Agricultural Waste, Springer, (2018), pp. 45-56
[6]
U.G. Eziefula.
Developments in utilisation of agricultural and aquaculture by-products as aggregate in concrete – a review.
Environ. Technol. Rev., 7 (2018), pp. 19-45
[7]
P. Shafigh, S. Salleh, H. Ghafari, H. Bin Mahmud.
Oil palm shell as an agricultural solid waste in artificial lightweight aggregate concrete.
Eur. J. Environ. Civil Eng., 22 (2018), pp. 165-180
[8]
S. Nasir, M. Hussein, Z. Zainal, N. Yusof, S. Mohd Zobir.
Electrochemical energy storage potentials of waste biomass: oil palm leaf- and palm kernel shell-derived activated carbons.
Energies, 11 (2018), pp. 3410
[9]
W.L. Nam, X.Y. Phang, M.H. Su, R.K. Liew, N.L. Ma, M.H.N.B. Rosli, S.S. Lam.
Production of bio-fertilizer from microwave vacuum pyrolysis of palm kernel shell for cultivation of Oyster mushroom (Pleurotus ostreatus).
Sci. Total Environ., 624 (2018), pp. 9-16
[10]
R. Ntenga, E. Mfoumou, A. Béakou, M. Tango, J. Kamga, A. Ahmed.
Insight on the ultrastructure, physicochemical thermal characteristics and applications of palm kernel shells.
Mater. Sci. Appl., 9 (2018), pp. 790-796
[11]
I.I. Misnon, N.K.M. Zain, R. Jose.
Conversion of oil palm kernel shell biomass to activated carbon for supercapacitor electrode application.
Waste Biomass Valorization, (2018), pp. 1-10
[12]
S. Yamada, Y. Shang, I. Yamada, M. Tagaya.
Synthesis of phosphonate-containing mesoporous silica spheres under basic condition.
Adv. Powder Technol., (2019),
[13]
C. Channoy, S. Maneewan, C. Punlek, S. Chirarattananon.
Preparation and characterization of silica gel from bagasse ash.
Adv. Mater. Res., 1145 (2018), pp. 44-48
[14]
S. Rovani, J.J. Santos, P. Corio, D.A. Fungaro.
Highly pure silica nanoparticles with high adsorption capacity obtained from sugarcane waste ash.
ACS Omega, 3 (2018), pp. 2618-2627
[15]
N. Sapawe, N.S. Osman, M.Z. Zakaria, S.A.S.S.M. Fikry, M.A.M. Aris.
Synthesis of green silica from agricultural waste by sol–gel method.
Mater. Today: Proc., 5 (2018), pp. 21861-21866
[16]
D.S. Fardhyanti, R.D.A. Putri, O. Fianti, A.F. Simalango, A.E. Akhir.
Synthesis of silica powder from sugar cane bagasse ash and its application as adsorbent in adsorptive-distillation of ethanol–water solution.
MATEC Web of Conferences, vol. 237,
[17]
J.A.S. Costa, C.M. Paranhos.
Systematic evaluation of amorphous silica production from rice husk ashes.
J. Clean. Prod., 192 (2018), pp. 688-697
[18]
S.A.T.H.Y. Chandrasekhar, K.G. Satyanarayana, P.N. Pramada, P. Raghavan, T.N. Gupta.
Review processing, properties and applications of reactive silica from rice husk – an overview.
J. Mater. Sci., 38 (2003), pp. 3159-3168
[19]
J. Athinarayanan, V.S. Periasamy, M. Alhazmi, K.A. Alatiah, A.A. Alshatwi.
Synthesis of biogenic silica nanoparticles from rice husks for biomedical applications.
Ceram. Int., 41 (2015), pp. 275-281
[20]
Y. Liu, Y. Guo, Y. Zhu, D. An, W. Gao, Z. Wang, Y. Ma, Z. Wang.
A sustainable route for the preparation of activated carbon and silica from rice husk ash.
J. Hazard. Mater., 186 (2011), pp. 1314-1319
[21]
P. Lu, Y.L. Hsieh.
Highly pure amorphous silica nano-disks from rice straw.
Powder Technol., 225 (2012), pp. 149-155
[22]
G.G. Kaya, E. Yilmaz, H. Deveci.
Sustainable nanocomposites of epoxy and silica xerogel synthesized from corn stalk ash: enhanced thermal and acoustic insulation performance.
Compos. Part B: Eng., (2018),
[23]
S. Salakhum, T. Yutthalekha, M. Chareonpanich, J. Limtrakul, C. Wattanakit.
Synthesis of hierarchical faujasite nanosheets from corn cob ash-derived nanosilica as efficient catalysts for hydrogenation of lignin-derived alkylphenols.
Micropor. Mesopor. Mater., 258 (2018), pp. 141-150
[24]
P. Velmurugan, J. Shim, K.J. Lee, M. Cho, S.S. Lim, S.K. Seo, K.M. Cho, K.S. Bang, B.T. Oh.
Extraction, characterization, and catalytic potential of amorphous silica from corn cobs by sol–gel method.
J. Ind. Eng. Chem., 29 (2015), pp. 298-303
[25]
E.A. Okoronkwo, P.E. Imoisili, S.O.O. Olusunle.
Extraction and characterization of amorphous silica from corn cob ash by sol–gel method.
Chem. Mater. Res., 3 (2013), pp. 68-72
[26]
E.A. Okoronkwo, P.E. Imoisili, S.A. Olubayode, S.O.O. Olusunle.
Development of silica nanoparticle from corn cob ash.
Adv. Nanopart., 5 (2016), pp. 135-139
[27]
S. Affandi, H. Setyawan, S. Winardi, A. Purwanto, R. Balgis.
A facile method for production of high-purity silica xerogels from bagasse ash.
Adv. Powder Technol., 20 (2009), pp. 468-472
[28]
U. Zulfiqar, T. Subhani, S.W. Husain.
Synthesis and characterization of silica nanoparticles from clay.
J. Asian Ceram. Soc., 4 (2016), pp. 91-96
[29]
D. Kaliannan, S. Palaninaicker, V. Palanivel, M.A. Mahadeo, B.N. Ravindra, S. Jae-Jin.
A novel approach to preparation of nano-adsorbent from agricultural wastes (Saccharum officinarum leaves) and its environmental application.
Environ. Sci. Pollut. Res., (2018), pp. 1-10
[30]
P. Terzioğlu, S. Yücel, Ç. Kuş.
Review on a novel biosilica source for production of advanced silica-based materials: wheat husk.
Asia-Pacific J. Chem. Eng., (2018), pp. 2262
[31]
R.K. Marag, P.A. Giri.
Experimental investigation of temperature and reaction time for preparation of silica from wheat husk.
Int. J. Eng. Technol. Sci. Res., (2018), pp. 60-65
[32]
C.E. Brewer, K. Schmidt-Rohr, J.A. Satrio, R.C. Brown.
Characterization of biochar from fast pyrolysis and gasification systems.
Environ. Prog. Sustain. Energy, 28 (2009), pp. 386-396
[33]
J. Umeda, K. Kondoh.
High-purity amorphous silica originated in rice husks via carboxylic acid leaching process.
J. Mater. Sci., 43 (2008), pp. 7084-7090
[34]
Association of Official Analytical Chemists (AOAC).
Official Methods of Analysis of the Association of Analytical Chemists.
15th ed., Association of Analytical Chemists, (1990),
[35]
C. Belver, M.A. Bañares Muñoz, V. Miguel Angel.
Chemical activation of a kaolinite under acid and alkaline conditions.
Chem. Mater., 14 (2002), pp. 2033-2043
[36]
J. Madejova.
FTIR techniques in clay mineral studies.
Vib. Spectrosc., 31 (2003), pp. 1-10
[37]
B.N. Dudkin, I.V. Loukhina, E.G. Avvakumov, V.P. Isupov.
Application of mechnochemical treatment of disintegration of kaolinite with sulphuric acid.
Chem. Sust. Dev., 12 (2004), pp. 327-330
[38]
H. Suquet.
Effects of dry grinding and leaching on the crystal structure of chrysotile.
Clays Clay Miner., 37 (1989), pp. 439-445
[39]
U. Kalapathy, A. Proctor, J. Shultz.
An improved method for production of silica from rice hull ash.
Bioresour. Technol., 85 (2002), pp. 285-289
[40]
S. Demis, J.G. Tapali, V.G. Papadakis.
An investigation of the effectiveness of the utilization of biomass ashes as pozzolanic materials.
Constr. Build. Mater., 68 (2014), pp. 291-300
[41]
Z. Wua, H. Xiangc, T. Kima, M.S. Chund, K. Leea.
Surface properties of submicrometer silica spheres modified with aminopropyltriethoxysilane and phenyltriethoxysilane.
J. Colloid Interface Sci., 304 (2006), pp. 119-124
[42]
R. Mueller, H.K. Kammler, K. Wegner, S.E. Pratsinis.
OH surface density of SiO2 and TiO2 by thermogravimetric analysis.
Langmuir, 19 (2003), pp. 160-165
Copyright © 2019. SECV
Article options
Tools
es en pt
Política de cookies Cookies policy Política de cookies
Utilizamos cookies propias y de terceros para mejorar nuestros servicios y mostrarle publicidad relacionada con sus preferencias mediante el análisis de sus hábitos de navegación. Si continua navegando, consideramos que acepta su uso. Puede cambiar la configuración u obtener más información aquí. To improve our services and products, we use "cookies" (own or third parties authorized) to show advertising related to client preferences through the analyses of navigation customer behavior. Continuing navigation will be considered as acceptance of this use. You can change the settings or obtain more information by clicking here. Utilizamos cookies próprios e de terceiros para melhorar nossos serviços e mostrar publicidade relacionada às suas preferências, analisando seus hábitos de navegação. Se continuar a navegar, consideramos que aceita o seu uso. Você pode alterar a configuração ou obter mais informações aqui.