Malaysian Journal of Analytical Sciences, Vol 27 No 4 (2023): 777 - 789

POTENTIALITY OF NANOSILICA-DOPED CARBON DOTS AS FLUORESCENCE DETECTOR FOR COPPER (Cu²⁺) IONS

IN SIMULATED WASTEWATER

(Potensi Nanosilica-Didop Titik Carbon Sebagai Pengesan Pendaflour untuk Ion Kuprum (Cu²⁺) dalam Simulasi Air Sisa)

Rejie C. Magnaye^*, Donjun C. Aguda, Kristine Rose G. Gonzales, Kyla Marie T. Plaza,

and Jeoh Ysrael D. Silang

Department of Chemical Engineering,

College of Engineering,

Batangas State University – The National Engineering University,

Golden Country Homes Subdivision, Alangilan, Batangas City, Philippines

^*Corresponding Author: rejie.magnaye@g.batstate-u.edu.ph

Received: 6 February 2023; Accepted: 30 May 2023; Published: 22 August 2023

Abstract

Industrialization has a major impact on the ecosystem and the natural water composition particularly in places close to cities and manufacturing areas. Copper (Cu²⁺) ion is one of the heavy metals present in the industrial effluent and is considered to be a toxic heavy-metal contaminant accounting to its extreme persistence and bioaccumulation. Current techniques for determining Cu²⁺ ions in water include atomic absorption spectrometry (AAS), X-ray fluorescence spectrometry (XRF) and electrochemical methods, which provide high precision but have high maintenance costs and complicated preparation. Thus, an inexpensive, nontoxic and rapid sensing system for copper detection is needed. Herein, a simple and effective route for designing a fluorescence detector for Cu²⁺ ions tracing was developed through a microwave-assisted rapid synthesis of carbon dots and nanosilica from Taal volcanic as its dopant. The parameters affecting the performance of the Taal Volcanic Ash Nanosilica-doped Carbon Dots (TVA/SiO₂-Cdots), such as silica dosage, agitation speed and contact time were investigated and optimized. Under optimized conditions, the TVA/SiO₂-Cdots showed the detection of Cu²⁺ ions in simulated wastewater. The optical properties of the synthesized TVA/SiO₂-Cdots were determined using Fourier transform infrared spectroscopy (FTIR) and UV-Visible spectrophotometer which explained the quenching of TVA/SiO₂-Cdots photoluminescence upon addition of Cu²⁺ ions. It has functional groups of Amine, C=C and C-O bonds. The mathematical correlation between photoluminescence (PL) intensity ratio of SiO₂-Cdots and Cu²⁺ ion concentration in simulated wastewater was found to be a Gaussian equation. The result showed that the model has no significant difference with the detected concentrations using ultraviolet spectrophotometric screening method.

Keywords: carbon dots, copper ions, mathematical modelling, nanosilica, photoluminescence intensity

Abstrak

Pembangunan industri memberi impak besar terhadap ekosistem dan komposisi air semulajadi terutamanya di kawasan-kawasan berdekatan dengan bandar dan kawasan pembuatan. Ion kuprum (Cu²⁺) adalah salah satu daripada logam berat yang terdapat dalam air sisa industri dan dianggap sebagai pencemar logam berat toksik kerana ketekalan dan bioakumulasi yang tinggi. Teknik semasa untuk menentukan ion Cu²⁺ dalam air termasuk spektrometri serapan atom (AAS), spektrometri sinar-X pendaflour (XRF) dan kaedah elektrokimia, yang memberikan ketepatan yang tinggi tetapi memerlukan kos penyelenggaraan yang tinggi dan persediaan yang rumit. Oleh itu, sistem pengesanan untuk penentuan kuprum yang murah, tidak toksik dan cepat diperlukan. Di sini, satu laluan yang mudah dan berkesan untuk reka bentuk pengesan pendaflour untuk pengesan ion Cu²⁺ telah dibangunkan melalui sintesis cepat bantuan gelombang mikro titik karbon dan nanosilika dari abu gunung berapi Taal sebagai bahan tambahannya. Parameter-parameter yang mempengaruhi prestasi abu gunung berapi Taal nanosilika-didop titik karbon (TVA/SiO2-Cdots), seperti dos silika, kelajuan pengadunan, dan masa sentuhan telah dikaji dan dioptimumkan. Di bawah keadaan yang dioptimumkan, TVA/SiO₂-Cdots menunjukkan pengesanan ion Cu²⁺ dalam simulasi air sisa. Sifat optik TVA/SiO₂-Cdots yang disintesis ditentukan menggunakan spektroskopi inframerah transformasi Fourier (FTIR) dan spektrofotometer UV-Cahaya Nampak yang menjelaskan pemelindapan fotoluminesens TVA/SiO₂-Cdots dengan penambahan ion Cu²⁺. Ia mempunyai kumpulan berfungsi amina, C=C, dan C-O. Korelasi matematik antara nisbah intensiti fotoluminesen (PL) SiO₂-Cdots dan kepekatan ion Cu²⁺ dalam simulasi air sisa didapati sebagai persamaan Gauss. Keputusan menunjukkan bahawa model ini tidak mempunyai perbezaan yang signifikan dengan kepekatan yang dikesan menggunakan kaedah saringan spektrofotometri ultraungu.

Kata kunci: titik karbon, ion kuprum, pemodelan matematik, nanosilika, intensiti fotoluminesens

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