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Wang R.,Shanghai University of Engineering Science | Shin C.-H.,Seohae Environment Science Institute | Kim D.,University of Southern California | Ryu M.,Chonbuk National University | Park J.-S.,Kangwon National University
Environmental Earth Sciences | Year: 2016

The chemically enhanced kapok fiber was fabricated and tested for an industrial and environmental application, and optimized conditions for fiber modification and adsorption kinetic reactions were developed and evaluated. A significant improvement of the adsorption efficiency for the uptakes of Cd2+, Cu2+, Ni2+, Pb2+, and Zn2+ ions was observed with the chemically enhanced kapok fibers. The experimented metals were removed in the range of 95–99 % with a removal order such as Pb2+ > Cu2+ > Ni2+ ≈ Cd2+ > Zn2+. The adsorption kinetic models for such metals were also studied, indicating that chemisorption and reconstructed three-dimensional (3D) polymer structure were the determining rate step because of the higher correlation rate constant of the pseudo-second-order reaction. Along with metal adsorption study, the adsorption of methylene blue (MB) and trichloroethylene (TCE) with the chemically enhanced fiber was also estimated. © 2016, Springer-Verlag Berlin Heidelberg. Source


Wang R.,Chonbuk National University | Shin C.H.,Seohae Environment Science Institute | Park S.,Seohae Environment Science Institute | Cui L.,South-Central University for Nationalities | And 3 more authors.
Water, Air, and Soil Pollution | Year: 2015

As a biopolymer-modified building block, a poly-dopamine layer can be utilized with a wide range of inorganic and organic materials for an adsorptive and microbial remediation. In this study, dopamine (DOPA) was used as a structural platform to bind silver onto the surface of kapok fibers, and a composite of surfacemodified kapok fibers coatedwithDOPAalong with silver were successfully manufactured. After a silver-coating process, a very strong antibacterial property was exhibited against Staphylococcus aureus with a high antibacterial efficiency, over 99%, which could last for 48 h in peptone water. Enumeration determination was carried out in a spread plate method. For a comparative study, the antibacterial activity of raw kapok fibers and chemically enhanced kapok fibers with DOPA and silver was also evaluated. The results indicated that the chemically enhanced kapok fibers were very useful in controlling a microbial activity on a surface environment. © Springer International Publishing 2014. Source


Wang R.,Chonbuk National University | Shin C.-H.,Seohae Environment Science Institute | Park S.,Seohae Environment Science Institute | Park J.-S.,Kangwon National University | And 3 more authors.
Environmental Earth Sciences | Year: 2014

The feasibility of the industrial application of kapok fiber for the removal of lead (II) ions from aqueous stream was evaluated in this study. The fiber was modified using NaOH solution and also was oxidized with NaClO2solution. Both of the chemically enhanced kapok fibers showed a high adsorption efficiency, which was 23.4 and 34.6 mg/g, respectively, while unmodified kapok fibers had 4.70 mg/g. Kinetic reactions and their rate constants exhibited that the removal of lead was linearly correlated with adsorption capacity of the modified and oxidized kapok fibers. Adsorption isotherm of the experiment fitted very well with the Langmuir model for the chemically enhanced kapok fibers. Adsorption capacity decreased with a decrease in the pH. The recycling process of the used kapok fibers was also carried out and the results found that kapok fibers were reusable with relatively high regeneration rate. © 2014, Springer-Verlag Berlin Heidelberg. Source


Kim Y.K.,Chonbuk National University | Yoon D.J.,Sunchon National University | Shin C.H.,Seohae Environment Science Institute | Hee R.M.,Chonbuk National University | And 2 more authors.
Advanced Materials Research | Year: 2013

Magnesium is demanded increasing in aerospace, electronics industry and medical field requires the surface treatment method. That allows increasing the corrosion resistance in order to put to practical use as products. The spark anodized treatment method in this study used was anodized depending on the various times to 1-4 minutes with a current density of 300 mA/cm2 in the constant-current mode that duty cycle is 50% and frequency is 125 Hz by a bipolar pulse power. And the characteristics of the film were evaluated. This treatment method is to obtain the uniform film by reducing the applied voltage on the surface by adding 0.1 M Sodium silicate (Na2SiO3) in the mixed solution of 2.0 M Sodium hydroxide (NaOH) and 0.1M Sodium phosphate (Na3PO4). It aims to express brown or dark brown color by adding Potassium permanganate, and to improve the corrosion resistance. After anodization treatment, the surface characteristics were analyzed using SEM, XRD and illuminance meter, and Vickers hardness was measured. In order to evaluate of corrosion resistance, the corrosion potential and corrosion current were measured by potentiodynamic method in 3.5 wt. % NaCl electrolyte. The critical voltage required to generate the oxidized layer could be lower depending on the addition of (Na2SiO3) and (KMnO4). The size of a pore was reduced depending on the processing time, and the thickness of the film was grown in proportion to it. As the result of XRD, a new peak of Mg0.9Mn0.1O was formed, and the peak of parent metal was reduced by the increase of the oxide. By the potentiodynamic polarization behavior, the value of corrosion potential was increased and the corrosion current density was decreased and the corrosion resistance was improved. © (2013) Trans Tech Publications, Switzerland. Source

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