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9 pages, 8799 KiB

Open AccessCommunication

Superhydrophobic Coatings on Cellulose-Based Materials with Alkyl Ketene Dimer Pickering Emulsion: Fabrication and Properties

by Yating Wang, Yuanfei Huang, Jing Zhong and Chenghua Yu

Coatings 2023, 13(11), 1829; https://doi.org/10.3390/coatings13111829 - 25 Oct 2023

Cited by 4 | Viewed by 2392

Abstract

In this study, a stable alkyl ketene dimer (AKD) Pickering emulsion was obtained using chitosan and titanium dioxide (TiO₂) as effective emulsifiers to disperse AKD. Superhydrophobic filter paper was prepared, using the filter paper as the substrate, by dipping it into AKD Pickering emulsion and then drying the coating papers at different temperature. The contact angle of the treated filter papers dried at 45 °C could reach more than 150°, and these filter papers effectively separated oil–water mixtures with an efficiency of over 93%. It is worth noting that the preparation process of the superhydrophobic material was simple and mild, and all the raw material was green without secondary pollution to the environment, so it has great practical application potential. This experiment could provide a new idea for the preparation of AKD superhydrophobic coatings and broaden their application. Full article

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14 pages, 3600 KiB

Open AccessEditor’s ChoiceArticle

A Simple Method for Synthesis of Chitosan Nanoparticles with Ionic Gelation and Homogenization

by Nicolas Van Bavel, Travis Issler, Liping Pang, Max Anikovskiy and Elmar J. Prenner

Molecules 2023, 28(11), 4328; https://doi.org/10.3390/molecules28114328 - 25 May 2023

Cited by 48 | Viewed by 16463

Abstract

Chitosan nanoparticles (CNPs) are known to have great utility in many fields (pharmaceutical, agricultural, food industry, wastewater treatment, etc.). In this study we aimed to synthesize sub-100 nm CNPs as a precursor of new biopolymer-based virus surrogates for water applications. We present a simple yet efficient synthesis procedure for obtaining high yield, monodisperse CNPs with size 68–77 nm. The CNPs were synthesized by ionic gelation using low molecular weight chitosan (deacetylation 75–85%) and tripolyphosphate as crosslinker, under rigorous homogenization to decrease size and increase uniformity, and purified by passing through 0.1 μm polyethersulfone syringe filters. The CNPs were characterized using dynamic light scattering, tunable resistive pulse sensing, and scanning electron microscopy. We demonstrate reproducibility of this method at two separate facilities. The effects of pH, ionic strength and three different purification methods on the size and polydispersity of CNP formation were examined. Larger CNPs (95–219) were produced under ionic strength and pH controls, and when purified using ultracentrifugation or size exclusion chromatography. Smaller CNPs (68–77 nm) were formulated using homogenization and filtration, and could readily interact with negatively charge proteins and DNA, making them an ideal precursor for the development of DNA-labelled, protein-coated virus surrogates for environmental water applications. Full article

(This article belongs to the Special Issue Chitosan, Chitosan Derivatives and Their Applications)

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11 pages, 2245 KiB

Open AccessArticle

Evaluation of the Bioaerosol Inactivation Ability of Chitosan-Coated Antimicrobial Filters

by Ying-Fang Hsu, Chi-Yu Chuang and Shinhao Yang

Int. J. Environ. Res. Public Health 2021, 18(13), 7183; https://doi.org/10.3390/ijerph18137183 - 5 Jul 2021

Cited by 7 | Viewed by 2733

Abstract

This work considers the enhancement of indoor bioaerosol removal efficiency by liquid coating of the antimicrobial agent chitosan onto polypropylene fibrous filters (CCFs). Escherichia coli (E. coli) and Bacillus subtilis (B. subtilis) were chosen as the tested bioaerosols. The results revealed that 2.5% (w/w) of CCFs have significantly higher bioaerosol survival capability (23% and 34% of E. coli and B. subtilis, respectively), compared to an untreated filter (65% and 64% for E. coli and B. subtilis, respectively). Increasing face velocity and relative humidity during operating CCFs could reduce the bioaerosol removal capability. The regression analysis of the experimental findings demonstrated that the higher coating concentration of chitosan had the most positive influence on bioaerosol removal, while the face velocity and relative humidity had a negative influence, but a milder effect was observed (R² = 0.83 and 0.81 for E. coli and B. subtilis bioaerosols, respectively). A CCF-loaded air-cleaning device was tested in a real indoor environment and resulted in 80.1% bioaerosol removal within 3 h of operating, which suggests that the chitosan-coated filter has the potential for further application in improving indoor air quality in the future. Full article

(This article belongs to the Special Issue State-of-the-Art Environmental Science and Technology)

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14 pages, 3174 KiB

Open AccessCommunication

Humidity Sensing by Chitosan-Coated Fibre Bragg Gratings (FBG)

by Rosaria D’Amato, Andrea Polimadei, Gaetano Terranova and Michele Arturo Caponero

Sensors 2021, 21(10), 3348; https://doi.org/10.3390/s21103348 - 12 May 2021

Cited by 26 | Viewed by 3704

Abstract

In this work, we report novel relative humidity sensors realized by functionalising fibre Bragg gratings with chitosan, a moisture-sensitive biopolymer never used before for this kind of fibre optic sensor. The swelling capacity of chitosan is fundamental to the sensing mechanism. Different samples were fabricated, testing the influence of coating design and deposition procedure on sensor performance. The sensitivity of the sensors was measured in an airtight humidity-controlled chamber using saturated chemical salt solutions. The best result in terms of sensitivity was obtained for a sensor produced on filter paper substrate. Tests for each design were performed in the environment, lasted several days, and all designs were independently re-tested at different seasons of the year. The produced sensors closely followed the ambient humidity variation common to the 24-h circadian cycle. Full article

(This article belongs to the Special Issue Feature Papers in Physical Sensors Section 2020)

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