Preparation of calcium alginate-encapsulated sulfur particles and their application in metal nanoparticle capture: A case study of silver nanoparticles

Lee, Koon Ming and Yoong, Wei Chuen and Loke, Chui Fung and Juan, Joon Ching and Yusoff, Khatijah and Mohtarrudin, Norhafizah and Lim, Teck Hock (2021) Preparation of calcium alginate-encapsulated sulfur particles and their application in metal nanoparticle capture: A case study of silver nanoparticles. Science Asia, 47 (1). 42+. ISSN 1513-1874, DOI https://doi.org/10.2306/scienceasia1513-1874.2021.S006.

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Abstract

Uniform anisotropic sulfur particles of 5.5 +/- 0.4 mu m in length, 3.9 +/- 0.4 mu m in width/thickness and an aspect ratio of 1.4 were successfully synthesized for the first time via the reaction of thiosulfate with a weak acid in the presence of sodium alginate which acted as a surfactant to impart water dispersibility and bestow particle size control. The sulfur particles with a zeta potential measured to be -29.5 mV were structurally characterized using PXRD and FESEM. After purification, the alginate-protected sulfur particles were discharged into a calcium chloride solution to produce fibrous calcium alginate-encapsulated sulfur composite (Ca-Alg-S) via ionotropic gelation. Ca-Alg-S was tested as absorbent of silver nanoparticles (Ag NPs) and compared to Ca-Alg gel absorbent. The Ag NPs were produced using sodium alginate as both surfactant and reducing agent under microwave-assisted heating to ensure the effect of surfactant on Ag capture was minimized. The effect of contact time on the removal efficiency of Ag NPs was established by tracking the decreasing absorbance of Ag NPs at 400 nm which was due to the surface plasmon resonance (SPR) band of Ag NPs of 10-20 nm in size. As high as 90% of Ag NP capture efficiency was achieved using Ca-Alg-S within 8 h under ambient conditions. The application of Ca-Alg-S may be extended in the future to other heavy metals including Hg, Cd, Ni and Pd which are known to react readily with sulfur, allowing effective wastewater treatment without the use of toxic sulfide or costly nanofiltration system.

Item Type: Article
Funders: Ministry of Education, Malaysia [Grant No: FRGS/1/2017/STG07/TARUC/02/1]
Uncontrolled Keywords: Sulfur particles; Alginate-gel-encapsulation; Ag nanoparticle removal; Capture efficiency
Subjects: Q Science > Q Science (General)
T Technology > T Technology (General)
Divisions: Deputy Vice Chancellor (Research & Innovation) Office > Nanotechnology & Catalysis Research Centre
Depositing User: Ms Zaharah Ramly
Date Deposited: 21 Apr 2022 08:06
Last Modified: 21 Apr 2022 08:06
URI: http://eprints.um.edu.my/id/eprint/28799

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