Sains Malaysiana 43(2)(2014): 253–259

Effect of Monoethanolamine Loading on the Physicochemical Properties

of Amine-Functionalized Si-MCM-41

(Kesan Penambahan Monoetanolamina terhadap Sifat Fiziko Kimia Si-MCM-41

Difungsikan oleh Amina)

ANITA RAMLI*¹, SOHAIL AHMED²& SUZANA YUSUP²

¹Department of Fundamental and Applied Sciences, Universiti Teknologi PETRONAS

Bandar Seri Iskandar, 31750 Tronoh, Perak, Malaysia

²Department of Chemical Engineering, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750 Tronoh, Perak, Malaysia

Diserahkan: 5 Februari 2013/Diterima: 26 Julai 2013

ABSTRACT

Siliceous mesoporous molecular sieve (Si-MCM-41) material with highly ordered hexagonal pore arrangement was synthesized at 373 K for 8-days duration by hydrothermal method, dried at 393 K and calcined at 823 K in N₂ atmosphere. The calcined Si-MCM-41 was later functionalized with 10-50 wt. % monoethanolamine (MEA) by impregnation method and dried in vacuum at 343 K. The MEA-Si-MCM-41 samples were characterized for their physicochemical properties with FTIR, XRD, TGA, HRTEM, FESEM, BET and elemental analysis. XRD results showed that the intensity of the characteristic peaks of Si-MCM-41 reduces with increasing loading of MEA indicating that the MEA molecules are loaded in the pores as well as on the surface of Si-MCM-41. The appearance of FTIR peaks corresponding to N-H, C-N and C-H bonds suggested that Si-MCM-41 has been functionalized with MEA. The presence of Si-O-Si peaks in FTIR spectra of MEA-Si-MCM-41 samples indicates that the hexagonal pore arrangement remains intact and this is supported by HRTEM images. FESEM images show that MEA-Si-MCM-41 samples became agglomerated with increase loading of MEA. TGA analyses show that the MEA-Si-MCM-41 samples are thermally stable up to 528 K. N₂ adsorption-desorption isotherms show that the textural properties of Si-MCM-41 material slowly change from a mesoporous material to non-porous material as the MEA loading increases due to pore filling effect during functionalization with MEA. Detection of N, C and H by elemental analysis confirms the presence of MEA in MEA-Si-MCM-41 samples.

Keywords: Functionalization; MEA; physicochemical properties; Si-MCM-41

ABSTRAK

Bahan penapis molekul berliang meso berasaskan silika (Si-MCM-41) dengan struktur liang secara heksagon yang sangat tersusun telah disintesis pada suhu 373 K selama 8 hari menggunakan kaedah hidroterma, dikeringkan pada 393 K dan dikalsinkan pada 823 K dalam aliran N₂. Si-MCM-41 yang telah dikalsinkan kemudiannya difungsikan dengan memuatkan 10-50 wt. % monoethanolamine (MEA) ke dalam liangnya menggunakan kaedah pengisitepuan dan dikeringkan menggunakan vakum pada suhu 343 K. Sifat fiziko kimia sampel MEA-Si-MCM-41 telah dianalisis dengan menggunakan FTIR, XRD, TGA, TEM, FESEM, BET dan analisis unsur. Keputusan XRD menunjukkan bahawa keamatan puncak Si-MCM-41 berkurangan dengan peningkatan muatan MEA menunjukkan bahawa molekul MEA telah dimuatkan ke dalam liang serta pada permukaan Si-MCM-41. Kehadiran puncak FTIR yang sepadan dengan ikatan N-H, C-N dan C-H mencadangkan bahawa Si-MCM-41 telah difungsikan oleh MEA. Kehadiran puncak Si-O-Si pada spektra FTIR bagi sampel MEA-Si-MCM-41 menunjukkan bahawa struktur liang secara heksagon masih utuh dan ini disokong oleh mikrograf HRTEM. Mikrograf FESEM menunjukkan bahawa sampel MEA-Si-MCM-41 menjadi bergumpal dengan peningkatan muatan MEA. Analisis TGA menunjukkan bahawa sampel MEA-Si-MCM-41 mempunyai kestabilan terma sehingga suhu 528 K. Isoterma penjerapan-penyahjerapan menunjukkan bahawa sifat tekstur bahan Si-MCM-41 berubah secara perlahan daripada bahan berliang meso kepada bahan tidak berliang setelah muatan MEA meningkat disebabkan kesan pengisian liang semasa pemfungsian dengan MEA. Pengesanan N, C dan H melalui analisis unsur mengesahkan kehadiran MEA di dalam sampel MEA-Si-MCM-41.

Kata kunci: MEA; pemfungsian; sifat fiziko kimia; Si-MCM-41

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*Pengarang untuk surat-menyurat; email: anita_ramli@petronas.com.my