Sains Malaysiana 45(3)(2016): 477–487
Photocatalytic Degradation of Some Charges
Aqueous Phase Pollutants using Nafion and Silica Modified TiO2
(Kemusnahan Fotomangkinan Beberapa Pencemar
Tercas Fasa Akueus menggunakan TiO2 Terubahsuai Nafion dan Silika)
CHOWDHURY, M.M.I.
& VOHRA, M.S.*
Department of Civil
and Environmental Engineering, King Fahd University of Petroleum
and Minerals, Dhahran, Kingdom of Saudi Arabia 31261
Diserahkan: 25
Disember 2014/Diterima: 26 Ogos 2015
ABSTRACT
The present study investigated
the use of modified titanium dioxide (TiO2)
based photocatalytic degradation (PCD) process for the removal of
some critical charged aqueous phase pollutants. First of all,
the use of Nafion TiO2 (Nf-TiO2)
and silica TiO2 (Si-TiO2)
for the removal of aqueous phase ammonia (NH4+/NH3)
species employing near UV lamp as energy source was studied.
The use of Nf-TiO2 enhanced
NH4+/NH3 PCD
with optimum removal noted for 1 mL of Nafion solution
coating per g of TiO2 and
respective overall NH4+/NH3 removal
was about 1.7 times higher compared to plain TiO2 at
6 h reaction time. Similarly the 0.5 mL silica solution coating
per g TiO2 sample,
also enhanced NH4+/NH3
removal with optimum efficiency similar to
Nf-TiO2.
The results from effect of ammonia concentration on to its PCD
using Nf-TiO2 indicated
that overall mass based NH4+/NH3 removal
was higher at greater NH4+/NH3 amounts
indicating high efficiency of Nf-TiO2. Similar trends were noted
for Si-TiO2 as
well. Furthermore, the results from modified TiO2 and
mixed NH4+/NH3 and
cyanide (CN-) systems indicated successful removal of co-pollutant
CN- along with simultaneous degradation of NH4+/NH3 species
at rates that were still higher than plain TiO2.
Nevertheless application of Nf-TiO2 for
the treatment of cationic dye methylene blue (MB)
indicated slower MB removal compared to plain TiO2 though
significant MB degradation using Nf-TiO2 could
still be achieved at pH3. Additionally the results
from solar radiation energized PCD process indicated positive role of
solar radiation for the removal of NH4+/NH3
species under a varying set of conditions.
Keywords: Cationic pollutants;
Nafion TiO2; photocatalysis; solar energy;
silica TiO2
ABSTRAK
Penyelidikan ini mengkaji tentang
penggunaan titanium dioksida terubah suai (TiO2)
berasaskan proses pemusnahan fotomangkinan (PCD)
untuk sesetengah bahan pencemar tercas fasa akueus kritikal. Pertama
ialah penggunaan semua TiO2 Nafion
(Nf-TiO2) dan TiO2 silika
(Si-TiO2) untuk penyingkiran ammonia fasa akueus spesies
(NH4+/NH3)
yang menggunakan lampu dekat UV sebagai sumber tenaga telah
dikaji. Penggunaan Nf-TiO2 mempertingkatkan
NH4+/NH3 PCD
dengan penyingkiran optimum bagi 1 mL salutan penyelesaian
Nafion untuk setiap g TiO2 dan
keseluruhan penyingkiran NH4+/NH3 adalah
1.7 kali lebih tinggi berbanding dengan TiO2 plain
pada masa tindak balas 6 jam. Lapisan larutan silika 0.5 mL untuk
setiap g sampel TiO2, juga mempertingkatkan penyingkiran
NH4+/NH3 dengan
kecekapan optimum menyerupai Nf-TiO2. Hasil daripada kesan
kepekatan ammonia kepada PCD dengan menggunakan Nf-TiO2 menunjukkan
bahawa jisim keseluruhan berasaskan penyingkiran NH4+/NH3 adalah
lebih tinggi daripada jumlah NH4+/NH3
yang menunjukkan kecekapan tinggi Nf-TiO2.
Trend serupa dilihat pada Si-TiO2. Selain itu, hasil daripada
TiO2 diubah
suai dan campuran NH4+/NH3 dan
sistem sianida (CN-) menunjukkan penyingkiran berjaya bersama
pencemar CN- bersama-sama dengan kemerosotan serentak
spesies NH4+/NH3 pada
kadar yang telah masih lebih tinggi daripada TiO2 biasa.
Walau bagaimanapun, aplikasi Nf-TiO2 untuk
rawatan kationik pencelup metilena biru (MB) menunjukkan penyingkiran MB
lebih perlahan berbanding TiO2 plain
walaupun kemerosotan MB secara bererti menggunakan Nf-TiO2 masih
boleh dicapai pada pH3. Tambahan pula keputusan daripada
sinaran suria yang mengecas proses PCD menunjukkan peranan positif radiasi
solar untuk penyingkiran spesies NH4+/NH3 di
bawah satu set keadaan yang berbeza.
Kata kunci: Bahan pencemar kationik; fotomangkinan; tenaga solar;
TiO2
Nafion; TiO2
silika
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*Pengarang untuk surat-menyurat; email:
vohra@kfupm.edu.sa