Sains Malaysiana 46(12)(2017): 2507–2514

http://dx.doi.org/10.17576/jsm-2017-4612-28

 

Enhanced Photodegradation of Phenol by ZnO Nanoparticles Synthesized through Sol-gel Method

(Peningkatan Fotopenguraian oleh Fenol dengan Sintesis ZnO Nano Zarah melalui Kaedah Sol-gel)

 

NIKATHIRAH YUSOFF¹, LI-NGEE HO^2*, SOON-AN ONG¹, YEE-SHIAN WONG¹, WANFADHILAH KHALIK¹ & MUHAMMAD FAHMI RIDZWAN¹

 

¹Water Research Goup (WAREG), School of Environmental Engineering, Universiti Malaysia Perlis, 02600 Arau, Perlis Indera Kayangan, Malaysia

 

²School of Materials Engineering, Universiti Malaysia Perlis, 02600 Arau, Perlis Indera Kayangan

Malaysia

 

Received: 13 April 2015/Accepted: 1 May 2017

 

ABSTRACT

Zinc oxide (ZnO) utilization in advanced oxidation process (AOP) via solar-photocatalytic process was a promising method for alternative treating wastewater containing phenol. The ZnO photocatalyst semiconductor was synthesized by sol-gel method. The morphology of the ZnO nanostructures was observed by using scanning electron microscope (SEM) and the crystallite phase of the ZnO was confirmed by x-ray diffraction (XRD). The objective of this study was to synthesis ZnO nanoparticles through a sol-gel method for application as a photocatalyst in the photodegradation of phenol under solar light irradiation. The photodegradation rate of phenol increased with the increasing of ZnO loading from 0.2 until 1.0 g. Only 2 h were required for synthesized ZnO to fully degrade the phenol. The synthesized ZnO are capable to totally degrade high initial concentration up until 45 mg L^-1 within 6 h of reaction time. The photodegradation of phenol by ZnO are most favoured under the acidic condition (pH3) where the 100% removal achieved after 2 h of reaction. The mineralization of phenol was monitored through chemical oxygen demand (COD) reduction and 92.6% or removal was achieved. This study distinctly utilized natural sunlight as the sole sources of irradiation which safe, inexpensive; to initiate the photocatalyst for degradation of phenol.

 

Keywords: Phenol; photocatalyst; photocatalytic; sol-gel; zinc oxide

 

ABSTRAK

Penggunaan zink oksida (ZnO) dalam proses pengudaraan lanjutan (PPL) melalui proses sinaran suria fotopemangkin merupakan kaedah alternatif untuk merawat air buangan yang mengandungi fenol. Pemangkin semikonduktor ZnO disintesis melalui kaedah sol-gel. Bentuk permukaan struktur nano ZnO dikenal pasti menggunakan analisis SEM dan fasa hablur ZnO disahkan melalui analisis XRD. Objektif kajian ini adalah untuk mensintesis ZnO berstruktur nano melalui kaedah sol-gel bertujuan untuk diaplikasikan sebagai pemangkin dalam proses fotopenguraian fenol di bawah sinaran suria. Kadar fotopenguraian fenol meningkat dengan peningkatan jumlah ZnO bermula daripada 0.2 hingga 1.0 g. Tempoh masa 2 jam diperlukan untuk ZnO sintesis mengurai fenol sepenuhnya. ZnO sintesis mampu untuk menguraikan kepekatan fenol yang tinggi sehingga 45 mg L^-1 dalam tempoh 6 jam masa tindak balas. Fotopenguraian fenol oleh ZnO sangat sesuai dalam keadaan berasid (pH3), dengan 100% penguraian dicatatkan selepas dua jam masa tindak balas. Penguraian lengkap fenol dikawal menerusi pengurangan keperluan oksigen lengkap (COD) dan sebanyak 92.6% penguraian dicapai. Kajian ini jelas menggunakan sinaran matahari semula jadi sebagai sumber sinaran tunggal yang selamat, murah dan mampu mengaktifkan pemangkin untuk penguraian fenol.

 

Kata kunci: Fenol; fotopemangkin; fotopemangkinan; sol-gel; zink oksida

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*Corresponding author; email: lnho@unimap.edu.my