Malaysian Journal of Analytical Sciences Vol 23 No 1 (2019): 109 - 115

DOI: 10.17576/mjas-2019-2301-13

 

 

 

OPTIMISATION OF THE COMPOSITION AND PROCESS PARAMETER OF CsH₂PO₄/NaH₂PO₄/SiO₂ SOLID ACID COMPOSITE VIA THE TAGUCHI METHOD

 

(Pengoptimuman Komposisi dan Parameter Proses Bagi Komposit Asid Pepejal CsH₂PO₄/NaH₂PO₄/SiO₂ Melalui Kaedah Taguchi)

 

Norsyahida Mohammad¹, Abu Bakar Mohamad^1,2, Abdul Amir Hassan Kadhum^1,2, Kee Shyuan Loh¹*

 

¹Fuel Cell Institute

²Department of Chemical and Process Engineering, Faculty of Engineering and Built Environment

Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia

 

*Corresponding author:  ksloh@ukm.edu.my

 

 

Received: 13 April 2017; Accepted: 17 April 2018

 

 

Abstract

Solid acid composites of CsH₂PO₄/NaH₂PO₄/SiO₂ (CDP/SDP/SiO₂) were synthesised with varied SDP to CDP and SiO₂ to CDP mole fractions. The composites were arranged for optimisation via the Taguchi method with L9 orthogonal array, which manipulates four factors: the amount of SDP, amount of SiO₂, amount of pressure used for pellet production and operating temperature. Responses were recorded as the averaged conductivity value for each experimental set. The composite powders were uniaxially pressed to form pellets of 1 mm thickness for conductivity measurements. Conductivity value was averaged from three readings and used in the signal-to-noise (S/N) ratio formula. The S/N ratio was set such that larger is better and calculated to maximise the response required for the analysis. Operating temperature has the largest effect on the conductivity value of solid acid composites, whereas the amount of SiO₂ has the smallest effect. The amount of SDP in the composite has a larger effect than the pressure applied during pellet production prior to the conductivity measurements. The optimised composite consists of 0.2 mole fraction of SDP to CDP and 0.3 mole fraction of SiO₂ to CDP pressed at 3 tonnes cm^-2 to produce pellets and tested at the temperature of 250 °C. The optimisation was validated by using analysis of variance from the Design-Expert^® software.

 

Keywords:  solid acid composite, caesium dihydrogen phosphate, Taguchi

 

Abstrak

Komposit asid pepejal CsH₂PO₄/NaH₂PO₄/SiO₂ (CDP/SDP/SiO₂) telah disintesis dengan pecahan mol SDP kepada CDP dan SiO₂ kepada CDP yang berbeza-beza. Komposit-komposit ini telah menjalani proses pengoptimuman melalui kaedah Taguchi, dengan susunan ortogonal L9 yang memanipulasi empat faktor iaitu kuantiti SDP, kuantiti SiO₂, kuantiti tekanan yang digunakan untuk penghasilan pelet dan suhu operasi. Output dicatatkan sebagai nilai kekonduksian purata bagi setiap set eksperimen. Serbuk komposit telah dimampatkan untuk membentuk pelet dengan ketebalan 1 mm untuk analisa kekonduksian. Nilai kekonduksian yang diperoleh dijadikan purata daripada tiga bacaan dan digunakan dalam formula nisbah isyarat kepada hingar (S/N). Nisbah S/N telah ditetapkan sebagai ‘lebih besar adalah lebih baik’ dan digunakan untuk memaksimakan tindak balas yang diperlukan untuk analisa. Suhu operasi mempunyai impak terbesar ke atas nilai kekonduksian komposit asid pepejal, manakala kuantiti SiO₂ mempunyai impak yang paling kecil ke atas nilai kekonduksian komposit asid pepejal. Kuantiti SDP dalam komposit mempunyai kesan yang lebih besar berbanding tekanan yang digunakan semasa penghasilan pelet sebelum analisa kekonduksian. Komposit yang telah dioptimumkan terdiri daripada 0.2 pecahan mol SDP kepada CDP dan 0.3 pecahan mol SiO₂ kepada CDP, memerlukan tekanan sebanyak 3 tan cm^-2 untuk menghasilkan pelet dan diuji pada suhu 250 °C. Proses pengoptimuman ini disahkan oleh analisa varians dari perisian Design-Expert^®.

 

Kata kunci:  komposit asid pepejal, sesium dihidrogen fosfat, Taguchi

 

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