Sains Malaysiana 44(3)(2015): 429–439


Enhancement of Gaseous BTEX Adsorption on RH-MCM-41 by Chlorosilanes

(Peningkatan Penjerapan Gas BTEX pada RH-MCM-41 oleh Klorosilana)




1Division of Environmental Technology, Joint Graduate School of Energy and Environment

King Mongkut's University of Technology Thonburi, 10140 Thailand


2Division of Environmental Technology, School of Energy, Environment and Materials

King Mongkut's University of Technology Thonburi, 10140 Thailand


3Department of Chemical Engineering, Thammasat University, 12120 Thailand


4Center for Energy Technology and Environment, Ministry of Education, Thailand


Received: 14 January 2014/Accepted: 25 August 2014



In this research, the surface hydrophobicity of a mesoporous molecular sieve synthesized from rice husk silica, called RH-MCM41 was improved via silylation techniqueto enhance the adsorption efficiency of non-polar volatile organic compound. The effect of chlorosilane leaving on was analyzed with three silanes containing different numbers of chloride leaving group; trimethylchlorosilane (TMCS), dimethyldichlorosilane (DMDCS) and methyltrichlorosilane (MTCS). The unmodified RH-MCM-41 was soaked in 100 mL of 5% v/v of silane reagent at 30ºC for 24 h. The results showed that the silane loading on the RH-MCM-41 was in the order of increasing number of leaving groups as MTCS > DMDCS > TMCS. The crystallinity results studied by X-ray diffractometry indicated that the silylation did not affect the hexagonal pattern of RH-MCM-41. However, the porosity of the silylated RH-MCM-41 was significantly decreased after silylation, especially by MTCS, due to pore blocking. After silylation, the adsorption performance of gaseous BTEX (benzene, toluene, ethylbenzene and xylene) on the silylated RH-MCM-41 was determined by gas chromatography equipped with flame ionization detector (GC-FID). From the results of humidity effect on adsorbability, the BTEX adsorption capacity of the unsilylated RH-MCM-41 was dropped a half, conversely the BTEX adsorption capacity of all silylated RH-MCM-41 was decreased in range of 20-30% when the relative humidity increased from 25 to 99%. This was indicated that the influence of humidity on the BTEX adsorption was relieved after silylation. In additions, the maximum BTEX adsorption capacity belonged to RH-MCM-41 silylated by TMCS which was recommended for the enhancement of non-polar volatile organic compounds adsorption.


Keywords: Adsorption; BTEX; MCM-41; rice husk silica; silylation



Dalam kajian ini, permukaan kehidrofobian penapis molekul mesoporous disintesis daripada sekam padi silika, dikenali sebagai RH-MCM41 bertambah baik melalui teknik sililasi untuk mempertingkatkan kecekapan penjerapan sebatian organik yang tidak berkutub. Kesan klorosilana yang tertinggal dianalisis dengan tiga silana yang mengandungi jumlah klorida berbeza meninggalkan kumpulan; trimetilklorosilana (TMCS), dimetildiklorisilana (DMDCS) dan metiltriklrosilana (MTCS). RH-MCM-41 yang tidak diubah suai, direndam dalam 100 mL 5% v/v bagi bahana uji silana pada 30ºC untuk 24 h. Hasil kajian menunjukkan bahawa bebanan silana ke atas RH-MCM-41 adalah dalam aturan penambahan bilangan meninggalkan kumpulan sebagai MTCS > DMDCS > TMCS. Keputusan habluran yang dikaji oleh belauan sinar-x menunjukkan bahawa sililasi tidak menjejaskan corak hexagon RH-MCM-41. Walau bagaimanapun, keliangan sililasi RH-MCM-41 menurun dengan sekata selepas sililasi, terutamanya MTCS, kerana menghalang liang. Selepas sililasi, prestasi penjerapan gas BTEX (benzena, toluena, etilbenzena dan xilena) pada sililasi RH-MCM-41 ditentukan melalui kromatografi gas dilengkapi dengan pengesan pengionan api (GC-FID). Hasil daripada serapan kelembapan menunjukkan kapasiti penjerapan BTEX sililasi RH-MCM-41 jatuh separuh, sebaliknya kapasiti penjerapan BTEX untuk semua sililasi RH-MCM-41 adalah menurun dalam julat 20-30% apabila kelembapan bandingan meningkat daripada 25 kepada 99%. Ini menunjukkan bahawa pengaruh kelembapan pada penjerapan BTEX lebih baik selepas sililasi. Sebagai tambahan, kapasiti maksimum penjerapan BTEX adalah kepunyaan RH-MCM-41 sililasi oleh TMCS yang dicadangkan untuk meningkatkan penjerapan-tidak berkutup organik meruap.


Kata kunci: BTEX; MCM-41; penjerapan; sekam padi silika; sililasi



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