Publications by authors named "Leo Choe Peng"

The biodegradable, nontoxic, and renewable carboxymethyl cellulose (CMC) hydrogel has been developed into a green adsorbent. However, the weak chemical interaction limits its adsorption capability and reusability. This work incorporated lignin with complex structure and ZnO nanoparticles with photocatalytic properties into CMC hydrogel beads to improve the removal of methylene blue (MB) through chemical interaction.

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Polyurethane (PU) paint with a hydrophobic surface can be easily fouled. In this study, hydrophilic silica nanoparticles and hydrophobic silane were used to modify the surface hydrophobicity that affects the fouling properties of PU paint. Blending silica nanoparticles followed by silane modification only resulted in a slight change in surface morphology and water contact angle.

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Decorating nanomaterials on graphene oxide (GO) can enhance its adsorption capacity and removal efficiency of water pollutants. In this study, for the first time, nano-sized polylactic acid (PLA) has been successfully decorated on the surface of GO through a facile synthesis approach. The adsorptive efficiency of GO-PLA for removing methylene blue (MB) and tetracycline (TC) from an aqueous solution was examined.

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Although anionic polyelectrolyte hydrogel beads offer attractive adsorption of cationic dyes, phosphate adsorption is limited by electrostatic interactions. In this work, carboxymethyl cellulose (CMC)/sodium alginate (SA) hydrogel beads were modified with calcium carbonate (CaCO) and/or bentonite (Be). The compatibility between CaCO and Be was proven by the homogeneous surface, as shown in the scanning electron microscopic images.

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Freshwater deficiency has become a significant issue affecting many nations' social and economic development because of the fast-growing demand for water resources. Nanofiltration (NF) is one of the promising technologies for water reclamation application, particularly in desalination, water, and wastewater treatment fields. Nevertheless, membrane fouling remains a significant concern since it can reduce the NF membrane performance and increase operating expenses.

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The implementation of hydrophobicity on membranes is becoming crucial in current membrane technological development, especially in membrane gas absorption (MGA). In order to prevent membrane wetting, a polypropylene (PP) dense layer coating was deposited on a commercial poly(vinylidene fluoride) (PVDF) hollow fiber membrane as a method of enhancing surface hydrophobicity. The weight concentration of PP pellets was varied from 10 mg mL to 40 mg mL and dissolved in xylene.

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Membrane distillation (MD) is a thermal technology for the desalination process that requires a hydrophobic microporous membrane to ensure that the membrane can maintain the liquid-vapor interface. This work aims to enhance the water permeation flux of the previously coated membrane by modifying the surface of the polytetrafluoroethylene hollow fiber (PTFE HF) membrane with a selected non-solvent such as acetone, cyclohexanone, and ethanol in low-density polyethylene as a polymeric coating solution. However, the modification using acetone and cyclohexanone solvents was unsuccessful because a reduction in membrane hydrophobicity was observed.

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Membrane distillation (MD) is an attractive technology for the separation of highly saline water used with a polytetrafluoroethylene (PTFE) hollow fiber (HF) membrane. A hydrophobic coating of low-density polyethylene (LDPE) coats the outer surface of the PTFE membrane to resolve membrane wetting as well as increase membrane permeability flux and salt rejection, a critical problem regarding the MD process. LDPE concentrations in coating solution have been studied and optimized.

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In the present work, palm kernel shell (PKS) biomass waste has been used as a low-cost and easily available precursor to prepare carbon dots (CDs) via microwave irradiation method. The impacts of the reacting medium: water and diethylene glycol (DEG), and irradiation period, as well as the presence of chitosan on the CDs properties, have been investigated. The synthesized CDs were characterized by several physical and optical analyses.

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Lignin was extracted from coconut husk via alkaline pulping, either Kraft or soda. The isolated lignin samples were classified as hydroxy-benzaldehyde, vanillin, and syringaldehyde type according to Fourier-transform Infrared Spectroscopy, H and C Nuclear Magnetic Resonance (NMR) spectra. Soda lignin (SL) showed higher thermal stability and glass transition temperature (T) than Kraft lignin (KL) as proven by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), respectively.

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