• Proceedings of the Membrane Society of Korea Conference
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• 2008.05a
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• pp.69-72
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• 2008

• Bulletin of the Korean Chemical Society
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• v.34 no.5
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• pp.1513-1520
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• 2013

Novel chitosan (CS) based membrane networks were developed by solution casting and followed by crosslinking with different crosslinkers such as glutaraldehyde, urea-formaldehyde, and thiourea-formaldehyde. The developed membrane networks were designated as CS-GA, CS-UF and CS-TF. Crosslinking reaction of CS membranes was confirmed by Fourier transform infrared spectroscopy. Membrane rigidity and compactness were studied by the differential scanning calorimetry. The surface morphology of CS membranes was characterized by scanning electron microscopy. The sorption behaviour with respect to contact time, initial pH and initial metal ion concentration were investigated. The maximum adsorption capacity of CS-GA, CS-UF and CS-TF sorbents was found to be 1.03, 1.2 and 1.18 mM/g for $Cu^{2+}$ and 1.48, 1.55 and 2.18 mM/g for $Ni^{2+}$ respectively. Swelling experiments have been performed on the membrane networks at $30^{\circ}C$. Desorption studies were performed in acid media and EDTA and it was found that the membranes are reusable for the metal ion removal for three cycles. The developed membranes could be successfully used for the separation of $Cu^{2+}$ and $Ni^{2+}$ metal ions from aqueous solutions.

• Journal of Korean Society of Water and Wastewater
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• v.33 no.3
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• pp.205-213
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• 2019

Batch adsorption tests were performed to evaluate the applicability of adsorption kinetic model by using hydrogel chitosan bead crosslinked with glutaraldehyde (HCB-G) for Cu(II) as cation and/or phosphate as anion. Pseudo first and second order model were applied to determine the sorption kinetic property and intraparticle and Boyd equation were used to predict the diffusion of Cu(II) and phosphate at pore and boundary-layer, respectively. According to the value of theoretical and experimental uptake of Cu(II) and phosphate, pseudo second order is more suitable. On comparison with the value of adsorption rate constant (k), phosphate kinetic was 2-4 times faster than that of Cu(II) at any experimental condition indicating the electrostatic interaction between ${NH_3}^+$ and phosphate is dominated at the presence of single component. However, when Cu(II) and phosphate simultaneously exist, the value of k for phosphate was sharply decreased and then the difference was not significant. Both diffusion models confirmed that the sorption rate was controlled by film mass transfer at the beginning time (t < 3 hr) and pore diffusion at next time section (t > 6 hr).

• Fashion & Textile Research Journal
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• v.23 no.6
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• pp.836-843
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• 2021

Recently, with an increase of interest in hygiene of textile products, research related to finishing technology to impart various functionalities, such as antibacterial and deodorizing properties, has also required. Therefore, in this study, the improvement of comfort was examined by analyzing the change of moisture characteristics and antibacterial and deodorizing properties of underwear fabric by chitosan microcapsule(CH-M) finishing. The results revealed that moisture absorption time of the fabric shortened, diffusion rate increased, while absorption rate slightly increased because of microcapsule finishing. In addition, the one-way transfer capacity of the microcapsule finished fabric was 17.69, which improved moisture transfer to one side, while OMMC showed the values of 0.32 and 0.37 for untreated and finished fabrics, respectively, which slightly increased after finishing. In the case of untreated fabric, antibacterial activity was 89.0% against Staphylococcus aureus and 70.3% against Klebsiella pneumoniae; however, both strains showed 99.9% antibacterial activity by CH-M finishing. An excellent bacterial reduction rate was also observed. In the case of the CH-M finished fabric, there was a deodorization effect exceeding 99% up to 120 minutes, and it showed an excellent deodorization effect of more than 99% even after 10 repeated washings.

• Journal of Microbiology and Biotechnology
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• v.34 no.3
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• pp.663-672
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• 2024

The use of nanoparticles as a delivery system for a specific antigen could solve many limitations of mucosal vaccine applications, such as low immunogenicity, or antigen protection and stabilization. In this study, we tested the ability of nasally administered chitosan nanoparticles loaded with glycoprotein B of murine cytomegalovirus to induce an immune response in an animal model. The choice of chitosan nanoparticle type was made by in vitro evaluation of sorption efficiency and antigen release. Three types of chitosan nanoparticles were prepared: crosslinked with tripolyphosphate, coated with hyaluronic acid, and in complex with polycaprolactone. The hydrodynamic size of the nanoparticles by dynamic light scattering, zeta potential, Fourier transform infrared spectroscopy, scanning electron microscopy, stability, loading efficiency, and release kinetics with ovalbumin were evaluated. Balb/c mice were immunized intranasally using the three-dose protocol with nanoparticles, gB, and adjuvants Poly(I:C) and CpG ODN. Subsequently, the humoral and cell-mediated antigen-specific immune response was determined. On the basis of the properties of the tested nanoparticles, the cross-linked nanoparticles were considered optimal for further investigation. The results show that nanoparticles with Poly(I:C) and with gB alone raised IgG antibody levels above the negative control. In the case of mucosal IgA, only gB alone weakly induced the production of IgA antibodies compared to saline-immunized mice. The number of activated cells increased slightly in mice immunized with nanoparticles and gB compared to those immunized with gB alone or to negative control. The results demonstrated that chitosan nanoparticles could have potential in the development of mucosal vaccines.

• Macromolecular Research
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• v.17 no.10
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• pp.734-738
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• 2009

Biodegradable, pH-sensitive, glycol chitosan (GC) hydrogels were prepared using divinyl adipate (DVA) as a crosslinker and acetic acid as a catalyst. DVA has highly reactive double vinyl ester groups and GC contains a high density of hydroxyl groups, with two in every glucosamine unit. The transesterification reaction between vinyl esters and hydroxyl groups produced crosslinked GC hydrogels. The initial crosslinking reaction was monitored by measuring the viscosity of the reaction mixture. When DVA was added to the GC solution and heated to $50^{\circ}C$, the viscosity of the GC solution gradually increased, implying a crosslinking reaction and hydrogel formation. A new peak from the ester group was observed in the FTIR spectra of the GC hydrogels, confirming the crosslinking reaction. The synthesized GC hydrogel showed pH-dependent water absorbency, mainly due to the presence of amine groups ($-NH_2$) at the C-2 position of the glucosamine unit of GC. The water absorbency greatly increased at acidic pH and slightly decreased at alkaline pH. The GC hydrogel gradually degraded in $37^{\circ}C$ water due to hydrolysis of the ester bonds, which were intermolecular crosslinking sites. A red dye, 5-carboxyltetramethyl-rhodamine (CTMR), was entrapped in the GC hydrogels as a model compound. CTMR was released from GC hydrogels in two steps: an initial burst release mainly due to desorption and diffusion, and a second sustained release possibly due to gradual degradation.

• Advances in environmental research
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• v.5 no.1
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• pp.1-18
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• 2016

Magnetic nano-based sorbents have been synthesized for the recovery of two rare earth elements (REE: Nd(III) and Yb(III)). The magnetic nano-based particles are synthesized by a one-pot hydrothermal procedure involving co-precipitation under thermal conditions of Fe(III) and Fe(II) salts in the presence of chitosan. The composite magnetic/chitosan material is crosslinked with epichlorohydrin and modified by grafting alanine and serine amine-acids. These materials are tested for the binding of Nd(III) (light REE) and Yb(III) (heavy REE) through the study of pH effect, sorption isotherms, uptake kinetics, metal desorption and sorbent recycling. Sorption isotherms are well fitted by the Langmuir equation: the maximum sorption capacities range between 9 and 18 mg REE $g^{-1}$ (at pH 5). The sorption mechanism is endothermic (positive value of ${\Delta}H^{\circ}$) and contributes to increase the randomness of the system (positive value of ${\Delta}S^{\circ}$). The fast uptake kinetics can be described by the pseudo-second order rate equation: the equilibrium is reached within 4 hours of contact. The sub-micron size of sorbent particles strongly reduces the contribution of resistance to intraparticle diffusion in the control of uptake kinetics. Metal desorption using acidified thiourea solutions allows maintaining sorption efficiency for at least four successive cycles with limited loss in sorption capacity.

• Proceedings of the Membrane Society of Korea Conference
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• 1996.04a
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• pp.65-66
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• 1996

투과증발법은 상부에 액체공급액이 반투과막과 접촉하고 있고 하부에 진공에 가까운 낮은 압력을 걸어줌으로써 투과물이 수증기로 제거되는 막공정의 하나이다. 막을 통한 분리는 혼합물의 각 성분이 막내에서 다른 용해도와 확산도를 가지고 있기 때문에 발생한다. 이 공정의 지배적인 전달 메카니즘은 용해-확산 모델을 기초로 하고 있기 때문에 전형적으로 투과증발막은 대개 미세다공성 지지체에 얇은 선택성을 가진 재료를 입힌 복합막을 사용한다. 본 연구의 목적은 선택성을 가진 상부층막이 키토산인 복합막에서 지지체 구조의 영향을 살펴보고 키토산 복합막에 대한 물-에탄올 분리에 대해 최적의 모델을 찾는 것이다. 투과증발막소재로서의 키토산은 친수성기를 가지고 있으므로 물과 알코올의 분리에서 물만을 선택적으로 흡수하여 투과시키는 우수한 성능을 지니고 있으나 더욱 효과적인 막성능을 발휘하기 위해서는 지지체의 역할 및 막성능에 영향을 끼치는 여러 가지 인자들을 고려해서 막을 설계하는 것이 필요하다. 여기서는 상부층의 막두께, 지지체의 특성, 피드 농도 등을 변화시켜 가장 적당한 모델을 예측하였다.

• Proceedings of the Membrane Society of Korea Conference
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• 1998.04a
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• pp.124-126
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• 1998

1. INTRODUCTION : With good physical and chemical properties as a membrane material, poly(vinyl alcohol) (PVA) has been widely used for the preparation of several kinds of membranes for different applications. Considering such good physical chemical properties, some people have tried to use it for the formation of reverse osmosis (RO) membranes with a good chemical stability as well as high flux and high rejection rate. However, unfortunately, the performance of the RO membranes based on PVA has not been satisfactory yet. The PVA RO membranes thermally crosslinked have shown very low flux and relatively low salt rejection. In this experiment, ionic polymers such as sodium alginate and chitosan were used together with PVA to increase the nanofiltration performance of the PVA membranes.

• Journal of Veterinary Science
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• v.23 no.1
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• pp.1.1-1.11
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• 2022

Background: The poor bioadhesion capacity of tilmicosin resulting in treatment failure for Staphylococcus aureus small colony variants (SASCVs) mastitis. Objectives: This study aimed to increase the bioadhesion capacity of tilmicosin for the SASCVs strain and improve the antibacterial effect of tilmicosin against cow mastitis caused by the SASCVs strain. Methods: Tilmicosin-loaded chitosan oligosaccharide (COS)-sodium carboxymethyl cellulose (CMC) composite nanogels were formulated by an electrostatic interaction between COS (positive charge) and CMC (negative charge) using sodium tripolyphosphate (TPP) (ionic crosslinkers). The formation mechanism, structural characteristics, bioadhesion, and antibacterial activity of tilmicosin composite nanogels were studied systematically. Results: The optimized formulation was comprised of 50 mg/mL (COS), 32 mg/mL (CMC), and 0.25 mg/mL (TPP). The size, encapsulation efficiency, loading capacity, polydispersity index, and zeta potential of the optimized tilmicosin composite nanogels were 357.4 ± 2.6 nm, 65.4 ± 0.4%, 21.9 ± 0.4%, 0.11 ± 0.01, and -37.1 ± 0.4 mV, respectively; the sedimentation rate was one. Scanning electron microscopy showed that tilmicosin might be incorporated in nano-sized crosslinked polymeric networks. Moreover, adhesive studies suggested that tilmicosin composite nanogels could enhance the bioadhesion capacity of tilmicosin for the SASCVs strain. The inhibition zone of native tilmicosin, tilmicosin standard, and tilmicosin composite nanogels were 2.13 ± 0.07, 3.35 ± 0.11, and 1.46 ± 0.04 cm, respectively. The minimum inhibitory concentration of native tilmicosin, tilmicosin standard, and tilmicosin composite nanogels against the SASCVs strain were 2, 1, and 1 ㎍/mL, respectively. The in vitro time-killing curves showed that the tilmicosin composite nanogels increased the antibacterial activity against the SASCVs strain. Conclusions: This study provides a potential strategy for developing tilmicosin composite nanogels to treat cow mastitis caused by the SASCVs strain.