Research

13 pages, 2143 KiB

Open AccessArticle

The Separation of Chlorobenzene Compounds from Environmental Water Using a Magnetic Molecularly Imprinted Chitosan Membrane

by Guizhen Li, Jinyao Wang, Peng Zhu, Ying Han, Anqi Yu, Junhong Li, Zhaomei Sun and Kyung Ho Row

Polymers 2022, 14(15), 3221; https://0-doi-org.brum.beds.ac.uk/10.3390/polym14153221 - 08 Aug 2022

Cited by 3 | Viewed by 1712

Abstract

In this work, a magnetic molecularly imprinted chitosan membrane (MMICM) was synthesized for the extraction of chlorobenzene compounds in environmental water using the membrane separation method. The optimal extraction amount for chlorobenzene (9.64 mg·L⁻¹) was found to be a 1:2 solid [...] Read more.

In this work, a magnetic molecularly imprinted chitosan membrane (MMICM) was synthesized for the extraction of chlorobenzene compounds in environmental water using the membrane separation method. The optimal extraction amount for chlorobenzene (9.64 mg·L⁻¹) was found to be a 1:2 solid to liquid ratio, with a 20 min extraction time and 35 °C extraction temperature. This method proved to be successfully applied for the separation and trace quantification of chlorobenzene compounds in environmental water, with the limit of detection (LOD) (0.0016–0.057 ng·L⁻¹), limit of quantification (LOQ) (0.0026–0.098 ng·L⁻¹), and the recoveries ranging (89.02–106.97%). Full article

(This article belongs to the Special Issue Polymer Materials in Environmental Chemistry II)

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16 pages, 4089 KiB

Open AccessArticle

Optimizing the Conditions of Cationic Polyacrylamide Inverse Emulsion Synthesis Reaction to Obtain High–Molecular–Weight Polymers

by Tung Huy Nguyen, Nhung Thi Nguyen, Thao Thi Phuong Nguyen, Ngoc Thi Doan, Lam Anh Thi Tran, Linh Pham Duy Nguyen and Thanh Tien Bui

Polymers 2022, 14(14), 2866; https://0-doi-org.brum.beds.ac.uk/10.3390/polym14142866 - 14 Jul 2022

Cited by 6 | Viewed by 1837

Abstract

Cationic polyacrylamide (CPAM) emulsifier is widely applied in the wastewater treatment industry, mining industry, paper industry, cosmetic chemistry, etc. However, optimization of input parameters in the synthesis of CPAM by using the traditional approach (i.e., changing one factor while leaving the others fixed [...] Read more.

Cationic polyacrylamide (CPAM) emulsifier is widely applied in the wastewater treatment industry, mining industry, paper industry, cosmetic chemistry, etc. However, optimization of input parameters in the synthesis of CPAM by using the traditional approach (i.e., changing one factor while leaving the others fixed at a particular set of conditions) would require a long time and a high cost of input materials. Onsite mass production of CPAM requires fast optimization of input parameters (i.e., stirring speed, reaction temperature and time, the amount of initiator, etc.) to minimize the production cost of specific–molecular–weight CPAM. Therefore, in this study, we synthesized CPAM using reverse emulsion copolymerization, and proposed response surface models for predicting the average molecular weight and reaction yield based on those input parameters. This study offers a time–saving tool for onsite mass production of specific–molecular–weight CPAM. Based on our response surface models, we obtained the optimal conditions for the synthesis of CPAM emulsions, which yielded medium–molecular–weight polymers and high conversion, with a reaction temperature of 60–62 °C, stirring speed of 2500–2600 rpm, and reaction time of 7 h. Quadratic models showed a good fit for predicting molecular weight (Adj.R² = 0.9888, coefficient of variation = 2.08%) and reaction yield (Adj.R² = 0.9982, coefficient of variation = 0.50%). The models suggested by our study would benefit the cost–minimization of CPAM mass production, where one could find optimal conditions for synthesizing different molecular weights of CPAM more quickly than via the traditional approach. Full article

(This article belongs to the Special Issue Polymer Materials in Environmental Chemistry II)

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13 pages, 2929 KiB

Open AccessArticle

Fabrication of Polyethyleneimine-Functionalized Magnetic Cellulose Nanocrystals for the Adsorption of Diclofenac Sodium from Aqueous Solutions

by Xiaoyan Zhu, Jiaqi Tong, Hangzhen Lan and Daodong Pan

Polymers 2022, 14(4), 720; https://0-doi-org.brum.beds.ac.uk/10.3390/polym14040720 - 13 Feb 2022

Cited by 8 | Viewed by 2240

Abstract

Diclofenac sodium (DS), one of the most used non-steroidal anti-inflammatory drugs worldwide, is often detected in wastewater and natural water. This drug is ecotoxic, even at low concentrations. Therefore, it is essential to fabricate low-cost adsorbents that can easily and effectively remove DS [...] Read more.

Diclofenac sodium (DS), one of the most used non-steroidal anti-inflammatory drugs worldwide, is often detected in wastewater and natural water. This drug is ecotoxic, even at low concentrations. Therefore, it is essential to fabricate low-cost adsorbents that can easily and effectively remove DS from contaminated water bodies. In this study, a polyethyleneimine (PEI)-modified magnetic cellulose nanocrystal (MCNC) was prepared with a silane coupling agent as a bridge. TEM, FTIR, XRD, and VSM were used to demonstrate the successful preparation of MCNC-PEI. This composite adsorbent exhibited efficient DS removal. Furthermore, the adsorption performance of MCNC-PEI on DS was optimal under mildly acidic conditions (pH = 4.5). Adsorption kinetics showed that the adsorption process involves mainly electrostatic interactions. Moreover, the maximum adsorption capacity reached 299.93 mg/g at 25 °C, and the adsorption capacity only decreased by 9.9% after being reused five times. Considering its low cost, low toxicity, and high DS removal capacity, MCNC-PEI could be a promising adsorbent for treating DS-contaminated water. Full article

(This article belongs to the Special Issue Polymer Materials in Environmental Chemistry II)

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15 pages, 2261 KiB

Open AccessArticle

Synthesis, Characterization and Physicochemical Properties of Biogenic Silver Nanoparticle-Encapsulated Chitosan Bionanocomposites

by Sreelekha Ediyilyam, Mahesh M. Lalitha, Bini George, Sarojini Sharath Shankar, Stanisław Wacławek, Miroslav Černík and Vinod Vellora Thekkae Padil

Polymers 2022, 14(3), 463; https://0-doi-org.brum.beds.ac.uk/10.3390/polym14030463 - 24 Jan 2022

Cited by 8 | Viewed by 3122

Abstract

Green bionanocomposites have garnered considerable attention and applications in the pharmaceutical and packaging industries because of their intrinsic features, such as biocompatibility and biodegradability. The work presents a novel approach towards the combined effect of glycerol, tween 80 and silver nanoparticles (AgNPs) on [...] Read more.

Green bionanocomposites have garnered considerable attention and applications in the pharmaceutical and packaging industries because of their intrinsic features, such as biocompatibility and biodegradability. The work presents a novel approach towards the combined effect of glycerol, tween 80 and silver nanoparticles (AgNPs) on the physicochemical properties of lyophilized chitosan (CH) scaffolds produced via a green synthesis method.The produced bionanocomposites were characterized with the help of Fourier transform infrared spectroscopy (FTIR) and Scanning electron microscopy (SEM). The swelling behavior, water vapor transmission rate, moisture retention capability, degradation in Hanks solution, biodegradability in soil, mechanical strength and electrochemical performance of the composites were evaluated. The addition of additives to the CH matrix alters the physicochemical and biological functioning of the matrix. Plasticized scaffolds showed an increase in swelling degree, water vapor transmission rate and degradability in Hank’s balanced solution compared to the blank chitosan scaffolds. The addition of tween 80 made the scaffolds more porous, and changes in physicochemical properties were observed. Green-synthesized AgNPs showed intensified antioxidant and antibacterial properties. Incorporating biogenic nanoparticles into the CH matrix enhances the polymer composites’ biochemical properties and increases the demand in the medical and biological sectors. These freeze-dried chitosan-AgNPs composite scaffolds had tremendous applications, especially in biomedical fields like wound dressing, tissue engineering, bone regeneration, etc. Full article

(This article belongs to the Special Issue Polymer Materials in Environmental Chemistry II)

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12 pages, 4092 KiB

Open AccessArticle

Reconstruction of Fibroin Nanofibers (FNFs) via Electrospinning: Fabrication of Poly(vinyl alcohol)/FNFs Composite Nanofibers from Aqueous Solution

by Shohei Fujita, Huaizhong Xu, Yubing Dong and Yoko Okahisa

Polymers 2022, 14(1), 43; https://0-doi-org.brum.beds.ac.uk/10.3390/polym14010043 - 23 Dec 2021

Cited by 7 | Viewed by 2578

Abstract

Fibroin nanofibers (FNFs) achieved from physical treated silk can keep its original crystal structure, showing excellent mechanical properties, however, processing the FNFs into fibers is still a challenge. Herein, a brand-new environmentally friendly approach is proposed to manufacture FNFs-based composite nanofibers. The water-soluble [...] Read more.

Fibroin nanofibers (FNFs) achieved from physical treated silk can keep its original crystal structure, showing excellent mechanical properties, however, processing the FNFs into fibers is still a challenge. Herein, a brand-new environmentally friendly approach is proposed to manufacture FNFs-based composite nanofibers. The water-soluble polymer, poly(vinyl alcohol) PVA, was applied to increase the viscoelasticity of the spinning dope, and the content of FNFs can reach up to 20 wt%. The established phase image of spinning suggested that the concentrations ranging from 6 wt% to 8 wt% are premium to achieving relatively homogenous FNFs/PVA nanofibers. Random fibers were deposited on a fixed collector, while the fiber orientation intensity increased with the rotational speed of drum and started decreasing after 12 m/s. The mechanical properties of the composite nanofibers showed the similar tendency of variation of fiber orientation. In addition, chemical changes, crystallinity, and thermal properties of the composite nanofibers were further clarified by means of FTIR, DSC, and TG. As a result, high FNFs contained nanofibers with excellent thermal properties were created from an aqueous solution. This study is the first original work to realize the spinnability of FNFs, which provides a new insight of the FNFs. Full article

(This article belongs to the Special Issue Polymer Materials in Environmental Chemistry II)

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13 pages, 2914 KiB

Open AccessArticle

Kinetic and Thermodynamic Characteristics of Fluoride Ions Adsorption from Solution onto the Aluminum Oxide Nanolayer of a Bacterial Cellulose-Based Composite Material

by Alexander V. Dolganov, Vadim D. Revin, Sergey G. Kostryukov, Viktor V. Revin and Guang Yang

Polymers 2021, 13(19), 3421; https://0-doi-org.brum.beds.ac.uk/10.3390/polym13193421 - 05 Oct 2021

Cited by 3 | Viewed by 1810

Abstract

The described research examined the adsorption of fluoride ions from solution immobilized onto an aluminum oxide-coated bacterial cellulose-based composite material in which aluminum oxide had been deposited using ALD technology. The kinetic regularities of the adsorption of fluoride ions from the solution as [...] Read more.

The described research examined the adsorption of fluoride ions from solution immobilized onto an aluminum oxide-coated bacterial cellulose-based composite material in which aluminum oxide had been deposited using ALD technology. The kinetic regularities of the adsorption of fluoride ions from the solution as well as the mechanism of the processes were analyzed. The established equations show that the dynamics of adsorption correspond to first-order kinetics. Based on the Langmuir adsorption isotherms, we defined the adsorption equilibrium constants, parameter maximum adsorption, and change in Gibbs free energy. It is shown that, with increasing temperature, an increase in the reaction rate is constant, both forward and reverse. This testifies to the activated character of adsorption of the first fluoride on the surface of the sorbent based on bacterial cellulose modified with an alumina nanolayer. The activation energy of the desorption process is higher than the activation energy of the adsorption process, which characterizes the adsorption as ionic. The negative value of entropy indicates that in the course of sorption, an adsorption complex “aluminum-fluorine” is formed, where the system is more ordered than the initial system in which fluorine ions are in solution. The limiting stages of the process are revealed. The high sorption capacity of the resulting bacterial cellulose-based composite material obtained by means of biosynthesis through cultivation of the bacterium Komagataeibacter sucrofermentans B-11267 was demonstrated. Full article

(This article belongs to the Special Issue Polymer Materials in Environmental Chemistry II)

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15 pages, 4439 KiB

Open AccessArticle

Styrenated Oil Synthesis with Cyclic Carbonate Functional Groups on Polystyrene Segment

by Eser Bingöl and Ahmet Tuncer Erciyes

Polymers 2021, 13(14), 2343; https://0-doi-org.brum.beds.ac.uk/10.3390/polym13142343 - 17 Jul 2021

Cited by 1 | Viewed by 2856

Abstract

In this study, an oil-modified copolymer of 4-[(prop-2-en-1-yloxy)methyl]-1,3-dioxolan- 2-one (AGC) with styrene was synthesized, and the resulting copolymer (OBMI-St-AGC) was silane functionalized by inserting (3-aminopropyl) triethoxysilane (APTES) into the polymer backbone. OBMI-St-AGC was prepared by using an oil-based macroinitiator (OBMI) obtained by the [...] Read more.

In this study, an oil-modified copolymer of 4-[(prop-2-en-1-yloxy)methyl]-1,3-dioxolan- 2-one (AGC) with styrene was synthesized, and the resulting copolymer (OBMI-St-AGC) was silane functionalized by inserting (3-aminopropyl) triethoxysilane (APTES) into the polymer backbone. OBMI-St-AGC was prepared by using an oil-based macroinitiator (OBMI) obtained by the esterification of linseed oil partial glycerides (PGs) with 4,4-azobis-4-cyanopentanoyl chloride (ACPC). In the characterization, FTIR, ¹H NMR, TGA, and DSC analyses were applied. The silane-functionalized copolymer (OBMI-St-AGC-APTES) was crosslinked through the sol–gel process, and its crosslinked structure was determined. Full article

(This article belongs to the Special Issue Polymer Materials in Environmental Chemistry II)

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21 pages, 3765 KiB

Open AccessArticle

Eco-Friendly and Economic, Adsorptive Removal of Cationic and Anionic Dyes by Bio-Based Karaya Gum—Chitosan Sponge

by Rohith K. Ramakrishnan, Vinod V. T. Padil, Stanisław Wacławek, Miroslav Černík and Rajender S. Varma

Polymers 2021, 13(2), 251; https://0-doi-org.brum.beds.ac.uk/10.3390/polym13020251 - 13 Jan 2021

Cited by 39 | Viewed by 3965

Abstract

A novel, lightweight (8 mg/cm³), conjugate sponge of karaya gum (Kg) and chitosan (Ch) has been synthesized with very high porosity (~98%) and chemical stability, as a pH-responsive adsorbent material for the removal of anionic and cationic dyes from aqueous solutions. [...] Read more.

A novel, lightweight (8 mg/cm³), conjugate sponge of karaya gum (Kg) and chitosan (Ch) has been synthesized with very high porosity (~98%) and chemical stability, as a pH-responsive adsorbent material for the removal of anionic and cationic dyes from aqueous solutions. Experimental results showed that Kg-Ch conjugate sponge has good adsorption capacity for anionic dye methyl orange (MO: 32.81 mg/g) and cationic dye methylene blue (MB: 32.62 mg/g). The optimized Kg:Ch composition grants access to the free and pH-dependent ionizable functional groups on the surface of the sponge for the adsorption of dyes. The studies on the adsorption process as a function of pH, adsorbate concentration, adsorbent dose, and contact time indicated that the adsorption capacity of MB was decreased with increasing pH from 5 to 10 and external mass transfer together with intra-particle diffusion. The adsorption isotherm of the anionic dye MO was found to correlate with the Langmuir model (R² = 0.99) while the adsorption of the cationic MB onto the sponge was better described by the Freundlich model (R² = 0.99). Kinetic regression results specified that the adsorption kinetics were well represented by the pseudo-second-order model. The H-bonding, as well as electrostatic interaction between the polymers and the adsorption interactions of dyes onto Kg-Ch sponge from aqueous solutions, were investigated using attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy, and the highly wrinkled porous morphology was visualized in depth by field-emission scanning electron microscopy (FE-SEM) analysis. Moreover, the samples could be reused without loss of contaminant removal capacity over six successive adsorption-desorption cycles. The hierarchical three-dimensional sponge-like structure of Kg has not been reported yet and this novel Kg-Ch sponge functions as a promising candidate for the uninterrupted application of organic pollutant removal from water. Full article

(This article belongs to the Special Issue Polymer Materials in Environmental Chemistry II)

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