Synthesis and characterization of mixed-oxides (cr, w, ti, mn) catalysts to produce fame from palm fatty acid distillate, non-edible and waste cooking oils / Wan Zuraida Wan Kamis
Asid lemak metil ester “(FAME)” adalah bahan api alternatif yang dikenali sebagai
biodiesel dan boleh diperolehi melalui proses pemangkin homogen atau heterogen. Ia
adalah sumber tenaga boleh diperbaharui dan pembakaran adalah mesra alam sekitar
berbanding dengan bahan api petroleum. Penyelidikan ini bertujuan untuk mengkaji
mengenai logam oksida yang telah disintesis sebagai mangkin dalam tindak-balas
untuk menghasilkan FAME melalui esterifikasi/transesterifikasi sulingan asid lemak
sawit (PFAD), minyak masak tidak boleh dimakan seperti minyak jatropha (CJO)
dan minyak karanj (CKO), dan sisa minyak masak sawit (WCO). Mangkin-mangkin
tersebut telah dibangunkan dalam beberapa siri iaitu CrxWyO2 dimana 0 ≤ x≤ 2; 0 ≤
y≤ 2; CrxWyTizO2 dimana 0 ≤ x≤ 1; 0 ≤ y≤ 1; 0 ≤ z≤ 2; CrxWyMnwO2 dimana 0 ≤ x≤
1; 0 ≤ y≤ 1; 0 ≤ w≤ 2 dan (CrWO2)a(MnO2)b dimana a=1; 0 ≤ b≤ 2. Kesemua
mangkin telah disediakan melalui kaedah sol-gel dengan pelbagai nisbah berat logam
dan rawatan haba pada suhu pengkalsinan antara 300 °C dan 800 °C dan masa
pengkalsinan dari 1 jam hingga 6 jam. Beberapa teknik pencirian, termasuk BET,
“N2 adsorption-desorption isotherm”, “surface scanning and transmission electron
microscopy” (SEM dan TEM), “X-ray diffraction” ( XRD ), “Fourier Transformed
Infra-Red” ( FTIR ), asid-bes titratan dan “thermal gravimetric analysis” (TGA)
telah digunakan. Prestasi mangkin telah dinilai dalam reaktor kelompok pada
keadaan operasi yang berbeza termasuk suhu (110-200 °C), nisbah molar metanol
kepada “feed stock” (1:1-18:1 ), dos mangkin (1-5 wt. %) dan masa tindakbalas (1-7
jam). Analisa menunjukkan prestasi yang baik, dimana CrWO2 and CrWTiO2 telah
mencapai hasil FAME tertinggi, masing-masing sebanyak 86% dan 83%, dalam
esterifikasi PFAD yang mempunyai kandungan tinggi “FFA”. Kesan larut lesap
dalam mangkin-mangkin ini adalah minima dan boleh dijana semula untuk beberapa
kitaran, dimana CrWTiO2 boleh mengekalkan aktiviti yang lebih baik dengan
kandungan FAME lebih dari 75 % sehingga kitaran keempat berbanding CrWO2
yang boleh dikaitkan dengan luas permukaannya yang lebih tinggi. Walaupun begitu,
prestasi rendah yang ditunjukkan oleh CrWO2 dan CrWTiO2 dimana penghasilan
FAME kurang daripada 60% dalam transesterifikasi “feed stocks” yang mempunyai
kandungan FFA medium ke rendah seperti CJO, CKO dan WCO menunjukkan
pengubahsuaian selanjutnya diperlukan. Mangkin CrWMnO2 mencapai kandungan
FAME tertinggi sebanyak 85% melalui PFAD pada keadaan operasi terbaik iaitu 170
°C selama 3 h, 3:1 ( nisbah molar metanol kepada PFAD), 1.5 wt.% dos mangkin
dan boleh digunakan semula untuk beberapa kitaran. Pada masa yang sama,
transesterifikasi daripada CJO, CKO dan WCO pada keadaan operasi terbaik
memperolehi 73%, 80% dan 82% kandungan FAME, masing-masing. Kajian kinetik
telah menunjukkan esterifikasi PFAD dengan metanol boleh digambarkan oleh
tindak balas kadar tertib pertama dengan tenaga pengaktifan 18.95 kJmol-1 dan
pemalar kadar 0.0166 min-1. Kajian ini telah membuat kesimpulan bahawa mangkin
heterogen boleh dikitar semula yang telah disintesis melalui kaedah mampu milik
dan mesra alam berkesan sebagai pemangkin dalam tindak-balas untuk menghasilkan
FAME dari pelbagai “feed stocks” pada keadaan operasi sederhana.
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Fatty acid methyl ester (FAME) is an alternative fuel known as biodiesel that could
be obtained by homogeneous or heterogeneous catalytic processes. It is a renewable
energy source and its combustion is environmental friendly compared to petroleum
fuel. This study aims to investigate on the synthesized metal oxides as catalysts in the
reaction to produce FAME via esterification/transesterification of palm fatty acid
distillate (PFAD), the non-edible crude jatropha oil (CJO) and crude karanj oil
(CKO), and waste cooking palm oil (WCO). The catalysts were developed in several
series designated as; CrxWyO2 where 0 ≤ x≤ 2; 0 ≤ y≤ 2; CrxWyTizO2 where 0 ≤ x≤ 1;
0 ≤ y≤ 1; 0 ≤ z≤ 2; CrxWyMnwO2 where 0 ≤ x≤ 1; 0 ≤ y≤ 1; 0 ≤ w≤ 2 and
(CrWO2)a(MnO2)b where a=1; 0 ≤ b≤ 2. The catalysts were prepared via sol-gel
method at various metal weight ratios and heat treated at calcination temperatures
between 300 °C and 800 °C and calcination time of 1 h to 6 h. Several
characterization techniques, including BET, N2 adsorption-desorption isotherm,
surface scanning and transmission electron microscopy (SEM and TEM), X-ray
diffraction (XRD), Fourier Transformed Infra-Red (FTIR), acid-base titration, and
thermal gravimetric analysis (TGA) were used. The catalysts performances were
evaluated in a batch reactor at different operating conditions including temperature
(110-200 oC), methanol to feed stock molar ratio (1:1-18:1), catalyst dosage (1-5 wt.
%) and reaction time (1-7 h). The results have revealed good catalytic performances,
where CrWO2 and CrWTiO2 achieved highest FAME content of 86% and 83%,
respectively in the esterification of PFAD that comprised of high FFA content. The
effects of leaching in these catalysts were minimal and can be regenerated for several
cycles, where CrWTiO2 could maintain better activity above 75 % FAME content up
to the fourth cycle compared to CrWO2 that could be attributed to its higher surface
areas. In spite of this, the low performances below 60% FAME content of CrWO2
and CrWTiO2 in the transesterification of other feed stocks that constitute medium to
low FFA content such as CJO, CKO and WCO warrants further modification. The
catalyst CrWMnO2 achieved highest FAME content of 85% via PFAD at best
operating conditions of 170 °C for 3 h, 3:1 (methanol to PFAD molar ratio), 1.5
wt.% catalyst dosage and reusable for several cycles. While the transesterification of
CJO, CKO and WCO at best conditions obtained 73%, 80% and 82% FAME
content, respectively. The kinetic study revealed that the esterification of PFAD with
methanol was described by the first order reaction with activation energy of 18.95
kJmol-1 and the rate constant of 0.0166 min-1. The study concludes that the reusable
heterogeneous catalysts synthesized via affordable and environmental friendly
method could effectively catalyzed reaction to produce FAME from wide range of
feed stocks at moderate operating conditions.
Synthesis and characterization of mixed-oxides (cr, w, ti, mn) catalysts to produce fame from palm fatty acid distillate, non-edible and waste cooking oils / Wan Zuraida Wan Kamis
Synthesis and characterization of mixed-oxides (cr, w, ti, mn) catalysts to produce fame from palm fatty acid distillate, non-edible and waste cooking oils_Wan Zuraida Wan Kamis_K4_2015_MYMY