Sains Malaysiana 36(2):  175-181 (2007)

Perbandingan Hasil Pengoksidaan Elektrokimia Etanol dalam Larutan Alkali yang Menggunakan Elektrod Platinum-Polivinilklorida  (Pt-PVC) dan Kepingan Logam Pt

(Comparison of Electrooxidation Yield of Ethanol in Alkaline Medium using

Platinum –Polyvinyl chloride (Pt-PVC) and Pt Metal Foil Electrodes)

Riyanto, Jumat Salimon & Mohamed Rozali Othman

Makmal Elektrosintesis

Pusat Pengajian Sains Kimia dan Teknologi Makanan

Fakulti Sains dan Teknologi, Universiti Kebangsaan Malaysia

43600 UKM Bangi, Selangor D.E., Malaysia

Diserahkan: 6 Februari 2007 / Diterima: 20 Mac 2007

ABSTRAK

Elektrod platinum-polivinilklorida (Pt-PVC) untuk pengoksidaan elektrokimia etanol dalam larutan alkali telah direkabentuk. Elektrod Pt-PVC dibina dengan mencampurkan serbuk-serbuk logam platinum dengan PVC (95:5 w/w), diaduk untuk mendapatkan campuran yang homogen, ditambahkan dengan tetrahidrofuran (THF) untuk melarutkan PVC, dikeringkan, dimasukkan ke dalam acuan berdiameter 1 cm dan ditekan pada tekanan kira-kira 10 tan/cm². Kajian elektrokimia dilakukan menggunakan voltammetri kitaran (CV) dan kronokoulometri (CC). CV untuk etanol yang menggunakan elektrod-elektrod kepingan logam Pt dan Pt-PVC masing-masing memberikan ketumpatan arus 0.25 mA/cm² dan 85 mA/cm² untuk puncak penjerapan hidroksida. Ini menunjukkan bahawa elektrod Pt-PVC mempunyai nilai konduktiviti dan perilaku elektrokimia yang lebih baik untuk pengoksidaan etanol dalam KOH berbanding elektrod kepingan logam Pt. Hasil kajian mendapati bahawa terdapat peningkatan peratus hasil elektrolisis dari 3.64% kepada 23.64% asid asetik  apabila elektrod Pt-PVC digunakan untuk pengoksidaan elektrokimia 0.25 M etanol dalam larutan elektrolit 1.0 M KOH menggantikan elektrod kepingan logam Pt.

Kata kunci: Pt-PVC; pengoksidaan elektrokimia; etanol; asid asetik

ABSTRACT

A modification of platinum-polyvinyl chloride (Pt-PVC) electrode for the electrooxidation of ethanol in alkaline solution has been investigated. Pt-PVC electrode was prepared by mixed together platinum metal powder with PVC (95:5 w/w), homogenized, added with tetrahydrofuran  to dissolved the PVC, dried, put into 1 cm diameter mould and press at 10 ton/cm². Studies on electrochemicals behavior for Pt-PVC electrode were carried out using cyclic voltammetry and chronocoulometry modes. The higher current density for hydroxide adsorption peak were recorded, 0.25 mA/cm² and 85 mA/cm² respectively when Pt-PVC electrode was used compared to Pt electrode. This indicates that Pt-PVC electrode gives better conductivity and electrochemical behavior to electrooxidation of ethanol in KOH compared to Pt electrode. Result obtained shows the used of Pt-PVC electrode for electrooxidation of 0.25 M ethanol in 1.0 M KOH supporting electrolyte increased the percentage of acetic acid produced compared to Pt electrode. 

Keywords: Pt-PVC; elektrooxidation; ethanol; acetic acid 

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