Sains Malaysiana 43(3)(2014): 437–441

Synthesis and Photocatalysis of ZnO/γ-Fe₂O₃ Nanocomposite in Degrading Herbicide

2,4-dichlorophenoxyacetic Acid

(Sintesis dan Fotokatalisis ZnO/γ-Fe₂O₃ dalam Mendegradasi Herbisid Asid 2,4-diklorofenoksiasetik)

LEE KIAN MUN¹, ABDUL HALIM ABDULLAH²*, MOHD ZOBIR HUSSEIN²

 & ZULKARNAIN ZAINAL²

¹Department of Chemistry, Faculty of Science, Universiti Putra Malaysia

43400 Serdang, Selangor, Malaysia

²Advanced Materials and Nanotechnology Laboratory, Institute of Advanced Technology, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia

Received: 17 April 2013/Accepted: 12 July 2013

ABSTRACT

ZnO/γ-Fe₂O₃ catalysts were fabricated via a simple precipitation route using zinc acetate and iron acetate as the precursors and ammonia as the precipitant. The resulted nanocatalysts were subjected to heat treatment at 450°C for 2 h. The characteristics of the nanocomposite were investigated by various characterization techniques. The synthesized nanocomposite has an average particle size of 13 nm and a surface area of 17 m₂/g. The photocatalytic activity of ZnO/γ-Fe₂O₃ nanocomposite was evaluated by photodegrading 2,4-dichlorophenoxyacetic acid (2,4-D) under UV irradiation. The results showed that ZnO/γ-Fe₂O₃ nanocomposite exhibited enhanced photoactivity compared to pure ZnO with almost 20% increment within 4 h of reaction time. The result indicated the applicability of ZnO/γ-Fe₂O₃ nanocomposite to be used as photocatalyst in removing organic pollutants in wastewater.

Keywords: Photocatalytic degradation; precipitation; zinc oxide; 2,4-D

ABSTRAK

Mangkin ZnO/γ-Fe₂O₃ telah disintesis dengan kaedah pemendakan dengan menggunakan zink asetat dihidrat dan ferum asetat sebagai bahan pemula dan ammonia sebagai agen pemendak. Nanomangkin yang dihasilkan dikalsin pada 450°C selama 2 jam. Ciri mangkin yang dihasilkan dikaji dengan pelbagai analisis. ZnO/γ-Fe₂O₃ yang dihasilkan mempunyai purata saiz zarah sebesar 13 nm dan luas permukaan sebanyak 17 m2/g. Aktiviti fotopemangkinan bagi ZnO/γ-Fe₂O₃ yang disintesis telah dinilai dengan mendegradasi asid 2,4-diklorofenoksiasetik (2,4-D) di bawah radiasi cahaya ultraungu. Kajian menunjukkan bahawa peratusan penyingkiran 2,4-D oleh ZnO/γ-Fe₂O₃ melebihi ZnO sebanyak 20% dalam masa 4 jam. Ini menunjukkan ZnO/γ-Fe2O3 yang dihasilkan mampu diaplikasikan sebagai fotomangkin untuk menyingkirkan pencemar organik dalam air sisa.

Kata kunci: Fotokatalisis degradasi; pemendakan; zink oksida; 2,4-D

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*Corresponding author; email: halim@upm.edu.my