Malaysian Journal of Analytical Sciences, Vol 27 No 4 (2023): 693 - 701

THE EFFECTS OF pH ON MICROPLASTICS REMOVAL BY ELECTROCOAGULATION PROCESS USING NICKEL ELECTRODE

(Kesan pH Terhadap Penyingkiran Mikroplastik Melalui Kaedah Elektrokoagulasi Menggunakan Elektrod Nikel)

Nor Aimi Abdul Wahab^1,3, Nor Ku Nazatul Husna Mohd Jackariya¹, Norain Isa^1,2*, Norfaezatul Alysa Othman¹, Vicinisvarri Inderan¹ , Nur Fadzeelah Abu Kassim¹

¹Chemical Engineering Studies, College of Engineering,

Universiti Teknologi MARA, Cawangan Pulau Pinang, Permatang Pauh Campus,

13500 Pulau Pinang, Malaysia

²Waste Management and Resource Recovery (WeResCue) Group,

Chemical Engineering Studies, College of Engineering,

Universiti Teknologi MARA, Cawangan Pulau Pinang, Permatang Pauh Campus,

13500 Pulau Pinang, Malaysia

³Department of Applied Sciences,

Universiti Teknologi MARA, Cawangan Pulau Pinang, Permatang Pauh Campus,

13500 Pulau Pinang, Malaysia

^*Corresponding author: norain012@uitm.edu.my

Received: 25 September 2022; Accepted: 25 February 2023; Published: 22 August 2023

Abstract

pH plays an important role in microplastics (MPs) removal during the electrocoagulation (EC) process. This study investigates the influence of the initial pH on the removal of polypropylene microplastics (PPMPs) from artificial wastewater using an EC process utilizing nickel electrodes. The effect of the initial pH has been investigated by commencing several sets of continuous flow experiments at five different initial pH values (2, 4, 6, 8, and 10), keeping the concentration of PPMPs, size of PPMPs, and electrode distance constant at 250 ppm, 250 µm, and 2 cm, respectively. The results showed that the removal efficiency increased gradually from 25% at initial pH 2 and reached its maximum level at initial pH 8 with 67% removal. Then it slightly decreased as the initial pH increased to 10. The kinetic studies showed that the EC process followed a first-order kinetic model. It can be said that the most favorable supporting pH for PPMPs removal utilizing nickel electrodes in this EC treatment technique is pH 8 due to the predominant species having a high adsorption capacity for PPMPs as a pollutant. The result showed that pH plays an important role in PPMPs removal from wastewater via the EC process utilizing nickel electrodes.

Keywords: Electrocoagulation, polypropylene, microplastics, nickel electrode, pH

Abstrak

pH memainkan peranan penting dalam penyingkiran mikroplastik melalui kaedah elektrokoagulasi. Kajian ini dilaksanakan bagi melihat pengaruh pH terhadap penyingkiran mikroplastik polipropelena (PPMPs) daripada air buangan melalui kaedah elektrokoagulasi (EC) menggunakan elektrod nikel. Pengaruh pH telah disiasat melalui beberapa set eksperimen menggunakan lima pH awal yang berbeza (2, 4, 6, 8 dan 10) dengan mengekalkan masing-masing kepekatan PPMPs, saiz PPMPs, dan jarak elektrod pada 250 ppm, 250 µm, dan 2 cm. Keputusan yang diperolehi menunjukkan bahawa kecekapan penyingkiran meningkat secara beransur-ansur daripada 25% pada pH awal 2 dan mencapai tahap maksimum pada pH awal 8 dengan penyingkiran 67%, kemudian ia sedikit menurun apabila pH awal meningkat kepada 10. Kajian kinetik menunjukkan bahawa proses EC adalah mengikut model kinetik tertib pertama. Boleh dikatakan bahawa pH sokongan yang paling sesuai untuk penyingkiran PPMPs menggunakan nikel sebagai elektrod dalam teknik rawatan EC ini ialah pH 8 disebabkan oleh, spesis utama mempunyai kapasiti penjerapan yang tinggi untuk PPMPs sebagai bahan pencemar. Keputusan menunjukkan bahawa pH memainkan peranan penting dalam penyingkiran PPMPs daripada air sisa melalui proses EC menggunakan elektrod nikel.

Kata kunci: Elektrokoagulasi, polipropelena, mikroplastik, elektrod nikel, pH

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