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Displaying publications 21 - 26 of 26 in total

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Fulltext Anti-Fouling Double-Skinned Forward Osmosis Membrane with Zwitterionic Brush for Oily Wastewater Treatment

Ong CS, Al-Anzi B, Lau WJ, Goh PS, Lai GS, Ismail AF, et al.

Sci Rep, 2017 07 31;7(1):6904.
PMID: 28761159 DOI: 10.1038/s41598-017-07369-4

Despite its attractive features for energy saving separation, the performance of forward osmosis (FO) has been restricted by internal concentration polarization and fast fouling propensity that occur in the membrane sublayer. These problems have significantly affected the membrane performance when treating highly contaminated oily wastewater. In this study, a novel double-skinned FO membrane with excellent anti-fouling properties has been developed for emulsified oil-water treatment. The double-skinned FO membrane comprises a fully porous sublayer sandwiched between a highly dense polyamide (PA) layer for salt rejection and a fairly loose dense bottom zwitterionic layer for emulsified oil particle removal. The top dense PA layer was synthesized via interfacial polymerization meanwhile the bottom layer was made up of a zwitterionic polyelectrolyte brush - (poly(3-(N-2-methacryloxyethyl-N,N-dimethyl) ammonatopropanesultone), abbreviated as PMAPS layer. The resultant double-skinned membrane exhibited a high water flux of 13.7 ± 0.3 L/m2.h and reverse salt transport of 1.6 ± 0.2 g/m2.h under FO mode using 2 M NaCl as the draw solution and emulsified oily solution as the feed. The double-skinned membrane outperforms the single-skinned membrane with much lower fouling propensity for emulsified oil-water separation.

Matched MeSH terms: Nylons
Fulltext Characterization of Textile-Insulated Capacitive Biosensors

Ng CL, Reaz MB

Sensors (Basel), 2017 Mar 12;17(3).
PMID: 28287493 DOI: 10.3390/s17030574

Capacitive biosensors are an emerging technology revolutionizing wearable sensing systems and personal healthcare devices. They are capable of continuously measuring bioelectrical signals from the human body while utilizing textiles as an insulator. Different textile types have their own unique properties that alter skin-electrode capacitance and the performance of capacitive biosensors. This paper aims to identify the best textile insulator to be used with capacitive biosensors by analysing the characteristics of 6 types of common textile materials (cotton, linen, rayon, nylon, polyester, and PVC-textile) while evaluating their impact on the performance of a capacitive biosensor. A textile-insulated capacitive (TEX-C) biosensor was developed and validated on 3 subjects. Experimental results revealed that higher skin-electrode capacitance of a TEX-C biosensor yields a lower noise floor and better signal quality. Natural fabric such as cotton and linen were the two best insulating materials to integrate with a capacitive biosensor. They yielded the lowest noise floor of 2 mV and achieved consistent electromyography (EMG) signals measurements throughout the performance test.

Matched MeSH terms: Nylons
Comparison of Plaque Removal and Wear between Charcoal Infused Bristle and Nylon Bristle Toothbrushes: A Randomized Clinical Crossover Study

Kini V, Yadav S, Rijhwani JA, Farooqui A, Joshi AA, Phad SG

J Contemp Dent Pract, 2019 Mar 01;20(3):377-384.
PMID: 31204332

AIM: To compare plaque removal and wear between charcoal infused bristle toothbrushes (T1) and nylon bristle toothbrushes (T2) in a randomized clinical crossover study.
MATERIALS AND METHODS: A cross-over study was conducted in 2 phases of 6 weeks duration each with an intervening 2-week washout. Twenty-five participants meeting inclusion criteria were randomly allocated into groups A (13) and B (12). In phase 1: group A was assigned T1 and group B was assigned T2. Toothbrushing was advised twice daily for 2 minutes by modified bass technique after meals. At baseline, 3 weeks and 6 weeks the wear index (WI), plaque index (PI) and gingival index (GI) were recorded. Following washout in phase 2 group A was assigned T2 and group B was assigned T1 and the same study protocol was followed.
RESULTS: Intra-group comparison between baseline, 3 and 6 weeks by the paired t-test resulted in significant reduction in PI, GI and increase in WI (p <0.05) for T1 and T2. Inter-group comparison using the unpaired t-test resulted in WI for T1 being significantly higher (p <0.05) at 3 weeks and lower at 6 weeks (p <0.05) compared to T2. PI for T1 was significantly higher at 3 weeks (p <0.05) and lower at 6 weeks (p <0.05) compared to T2. No significant difference in GI scores between T1 and T2 at 3 and 6 weeks was observed (p >0.05).
CONCLUSION: Charcoal infused bristles demonstrated less wear and more plaque removal compared to nylon bristles.
CLINICAL SIGNIFICANCE: Charcoal infused bristles demonstrate less wear compared to nylon bristles.

Matched MeSH terms: Nylons
Thermal and mechanical characterization of composite materials from industrial plastic wastes and recycled nylon fibers for floor paving tiles application

Owen MM, Achukwu EO, Romli AZ, Abdullah AHB, Ramlee MH, Shuib SB

Waste Manag, 2023 Jul 01;166:25-34.
PMID: 37141784 DOI: 10.1016/j.wasman.2023.04.038

Industrial plastic waste is growing globally at an alarming rate and environmental pollution from traditional landfill disposal and incineration treatments are of great concern. As a strategy to reduce plastic pollution, value-added composite materials from industrial plastic wastes reinforced with recycled nylon fibers for use in floor paving tile applications were developed. This is to address the disadvantages of existing ceramic tiles which are relatively heavy, brittle, and expensive. The plastic waste composite structures were produced via compression molding technique at an optimized randomly oriented constant fiber volume fraction of 50 wt% after the initial sorting, cleaning, drying, pulverizing, and melt-mixing. The molding temperature, pressure, and time for the composite's structures were 220 ℃, 65 kg.cm-3, and 5 min respectively. The composites' thermal, mechanical, and microstructural properties were characterized in accordance with appropriate ASTM standards. From the results obtained, the differential scanning calorimetry (DSC) of mixed plastic wastes and nylon fiber wastes showed a processing temperature range of 130-180 ℃, and 250 ℃ respectively. Thermal degradation temperature (TGA) of the plastic and nylon fiber waste composites were stable above 400 ℃ with maximum bending strength, however, the reinforced plastic waste sandwiched composite structures had outstanding mechanical properties indicating unique characteristics suitable for floor paving tiles. Hence, the current research has developed tough and lightweight tiles composites that are economically viable, and their application will contribute to the development of the building and construction sectors thereby reducing about 10-15% of annual plastic waste generation and a sustainable environment.

Matched MeSH terms: Nylons
A review on polyamide thin film nanocomposite (TFN) membranes: History, applications, challenges and approaches

Lau WJ, Gray S, Matsuura T, Emadzadeh D, Chen JP, Ismail AF

Water Res, 2015 Sep 1;80:306-24.
PMID: 26011136 DOI: 10.1016/j.watres.2015.04.037

This review focuses on the development of polyamide (PA) thin film nanocomposite (TFN) membranes for various aqueous media-based separation processes such as nanofiltration, reverse osmosis and forward osmosis since the concept of TFN was introduced in year 2007. Although the total number of published TFN articles falls far short of the articles of the well-known thin film composite (TFC) membranes, its growth rate is significant, particularly since 2012. Generally, by incorporating an appropriate amount of nanofiller into a thin selective PA layer of a composite membrane, one could produce TFN membranes with enhanced separation characteristics as compared to the conventional TFC membrane. For certain cases, the resulting TFN membranes demonstrate not only excellent antifouling resistance and/or greater antibacterial effect, but also possibly overcome the trade-off effect between water permeability and solute selectivity. Furthermore, this review attempts to give the readers insights into the difficulties of incorporating inorganic nanomaterials into the organic PA layer whose thickness usually falls in a range of several-hundred nanometers. It is also intended to show new possible approaches to overcome these challenges in TFN membrane fabrication.

Matched MeSH terms: Nylons/chemistry*
Fulltext The role of ubiquitous metal ions in degradation of microplastics in hot-compressed water

Vo TP, Rintala J, Dai L, Oh WD, He C

Water Res, 2023 Oct 15;245:120672.
PMID: 37783176 DOI: 10.1016/j.watres.2023.120672

Hydrothermal processing (HTP) is an efficient thermochemical technology to achieve sound treatment and resource recovery of sewage sludge (SS) in hot-compressed subcritical water. However, microplastics (MPs) and heavy metals can be problematic impurities for high-quality nutrients recovery from SS. This study initiated hydrothermal degradation of representative MPs (i.e., polyethylene (PE), polyamide (PA), polypropylene (PP)) under varied temperatures (180-300 °C) to understand the effect of four ubiquitous metal ions (i.e., Fe3+, Al3+, Cu2+, Zn2+) on MPs degradation. It was found that weight loss of all MPs in metallic reaction media was almost four times of that in water media, indicating the catalytic role of metal ions in HTP. Especially, PA degradation at 300 °C was promoted by Fe3+ and Al3+ with remarkable weight loss higher than 95% and 92%, respectively, which was ca. 160 °C lower than that in pyrolysis. Nevertheless, PE and PP were more recalcitrant polymers to be degraded under identical condition. Although higher temperature thermal hydrolysis reaction induced severe chain scission of polymers to reinforce degradation of MPs, Fe3+ and Al3+ ions demonstrated the most remarkable catalytic depolymerization of MPs via enhanced free radical dissociation rather than hydrolysis. Pyrolysis gas chromatography-mass spectrometry (Py GC-MS) was further complementarily applied with GC-MS to reveal HTP of MPs to secondary MPs and nanoplastics. This fundamental study highlights the crucial role of ubiquitous metal ions in MPs degradation in hot-compressed water. HTP could be an energy-efficient technology for effective treatment of MPs in SS with abundant Fe3+ and Al3+, which will benefit sustainable recovery of cleaner nutrients in hydrochar and value-added chemicals or monomers from MPs.

Matched MeSH terms: Nylons