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

 

 

 

 

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