Seongnam, South Korea
Seongnam, South Korea

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Manvoudou Pissibanganga O.G.,Kookmin University | Jung J.,Hyorim Industries Inc. | Choi Y.,Kookmin University | Lee S.,Kookmin University | And 2 more authors.
Desalination and Water Treatment | Year: 2016

This study investigated the effect of microbubble floatation on the fouling of microfiltration membranes. Synthetic feed solutions containing either kaolin or alginic acid were used for the membrane filtration tests. A dissolve air flotation system using a pump-type microbubble generator was adopted as a pretreatment for microfiltration system. A multi-array submerged membrane filtration system was used to monitor the changes in transmembrane pressure with time under various operating conditions. Turbidity removal efficiency, particle counts, and fouling rate for the microfiltration membrane were measured after the microfiltration floatation. The effect of coagulant dose on the treated water quality and membrane performance was also investigated. Results showed that microbubble floatation without coagulant was effective to reduce membrane fouling by kaolin but it was not very effective to control fouling by alginate. With the aid of coagulant, microbubble flotation could control fouling by alginate. This is attributed to the removal mechanisms of foulants by microbubble floatation: suspended particles can be separated by the microbubbles without coagulant but dissolved organics can be only removed by the combined effect of coagulation and floatation. © 2016 Balaban Desalination Publications. All rights reserved.

Gwenaelle M.P.O.,Kookmin University | Jung J.,Hyorim Industries Inc. | Choi Y.,Kookmin University | Lee S.,Kookmin University
Desalination | Year: 2016

This study focused on the application of microbubbles (Mbs) to microfiltration (MF) pretreatment for reverse osmosis (RO) desalination. Experiments were performed using seawater as the feed water to a microfiltration system. Mbs, which were generated by a pump under 4bars of pressure, were applied prior to MF treatment. The MF flux was adjusted from 15L/m2/h to 45L/m2/h. The effect of coagulant addition to the Mbs reactor on the MF efficiency was also examined. Results indicated that Mbs without using coagulant were not effective to regard MF fouling. Although the turbidity of the water decreased, the fouling rate increased after the Mbs treatment. This is attributed to an increase in the fraction of small particles, which lead to an increase in specific cake resistance by decreasing the particle size. Combined with coagulation, microbubbles showed a higher ability to control MF fouling. The removal of small particles (<10μm) was also improved and the formation of cake layer was suppressed. The SDI5 was maintained low when seawater was pretreated with a combination of coagulation-microbubble-microfiltration. © 2016.

Lee H.,Korea Institute of Science and Technology | Shim E.,Korea Institute of Science and Technology | Yun H.-S.,Korea Institute of Science and Technology | Yun H.-S.,Yonsei University | And 6 more authors.
Environmental Science and Pollution Research | Year: 2015

Immobilized microalgae using silica (IMS) from Micractinium reisseri KGE33 was synthesized through a sol-gel reaction. Green algal waste biomass, the residue of M. reisseri KGE33 after oil extraction, was used as the biomaterial. The adsorption of Cu(II) on IMS was tested in batch experiments with varying algal doses, pH, contact times, initial Cu(II) concentrations, and temperatures. Three types of IMSs (IMS 14, 70, and 100) were synthesized according to different algal doses. The removal efficiency of Cu(II) in the aqueous phase was in the following order: IMS 14 (77.0 %) < IMS 70 (83.3 %) < IMS 100 (87.1 %) at pH 5. The point of zero charge (PZC) value of IMS100 was 4.5, and the optimum pH for Cu(II) adsorption was 5. Equilibrium data were described using a Langmuir isotherm model. The Langmuir model maximum Cu(II) adsorption capacity (qm) increased with the algal dose in the following order: IMS 100 (1.710 mg g−1) > IMS 70 (1.548 mg g−1) > IMS 14 (1.282 mg g−1). The pseudo-second-order equation fitted the kinetics data well, and the value of the second-order rate constant increased with increasing algal dose. Gibbs free energies (ΔG°) were negative within the temperature range studied, which indicates that the adsorption process was spontaneous. The negative value of enthalpy (ΔH°) again indicates the exothermic nature of the adsorption process. In addition, SEM-energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared (FT-IR), and X-ray photoelectron spectroscopy (XPS) analyses of the IMS surface reveal that the algal biomass on IMS is the main site for Cu(II) binding. This study shows that immobilized microalgae using silica, a synthesized biosorbent, can be used as a cost-effective sorbent for Cu(II) removal from the aqueous phase. © 2015 Springer-Verlag Berlin Heidelberg

Chekli L.,University of Technology, Sydney | Phuntsho S.,University of Technology, Sydney | Kim J.E.,University of Technology, Sydney | Kim J.,Gwangju Institute of Science and Technology | And 7 more authors.
Journal of Membrane Science | Year: 2016

Forward osmosis (FO) has been increasingly studied in the past decade for its potential as an emerging low-energy water and wastewater treatment process. However, the term "low-energy" may only be suitable for those applications in where no further treatment of the draw solution (DS) is required either in the form of pretreatment or post-treatment to the FO process (e.g. where the diluted DS is the targeted final product which can be used directly or simply discarded). In most applications, FO has to be coupled with another separation process in a so-called hybrid FO system to either separate the DS from the final product water or to be used as an advanced pre-treatment process to conventional desalination technologies. The additional process increases the capital cost as well as the energy demand of the overall system which is one of the several challenges that hybrid FO systems need to overcome to compete with other separation technologies. Yet, there are some applications where hybrid FO systems can outperform conventional processes and this study aims to provide a comprehensive review on the current state of hybrid FO systems. The recent development and performance of hybrid FO systems in different applications have been reported. This review also highlights the future research directions for the current hybrid FO systems to achieve successful implementation. © 2015 Elsevier B.V.

Lee J.,Pukyong National University | Choi J.Y.,Hyorim industries Inc. | Choi J.-S.,Korea Institute of Construction Technology | Chu K.H.,University of South Carolina | And 2 more authors.
Desalination | Year: 2016

A simple forward osmosis (FO) membrane characterization method was developed based on the combination of a single FO test and a statistical approach to avoid the pressurized reverse osmosis (RO) test, which may damage the tested FO membrane or misread the membrane characteristics. The single FO test measures water and reverse solute flux (J w and J s, respectively) in the active layer facing feed solution (AL-FS) mode using deionized water as feed and sodium chloride as draw solute. The statistical approach finds the most appropriate water permeability (A), salt permeability (B), and the resistance to salt diffusion within the support layer (K ICP) of the tested FO membrane to predict J w and J s using both internal concentration polarization (ICP) and external concentration polarization (ECP) models. Verifications using various experimental results in this work and other literatures reveal that the developed FO membrane characterization method determines more reliable parameters (A, B, and K ICP) than the conventional characterization method based on the RO experiment to predict the experimental J w and J s in FO processes. Consideration of ECP helps to determine more accurate FO membrane parameters (especially K ICP), but it is difficult to properly model ECP suitable for the tested FO membrane channel. © 2016 Elsevier B.V.

Kim S.,Pukyong National University | Lee I.S.,Hyorim Industries Inc | Kim K.J.,Doosan Heavy Industries and Construction | Shon D.M.,Pukyong National University | Kang L.S.,Pukyong National University
Desalination and Water Treatment | Year: 2011

Well-controlled laboratory scale experiments were carried out to estimate the performance of dual media filtration (DMF) and ultrafiltration (UF) as a pretreatment for seawater reverse osmosis (SWRO) processes. Raw seawater was taken from the place close to the construction site of the SEAHERO test-bed of 45,000 m3/d in capacity, which is planning to be operated from 2013. The raw seawater turbidity was rather low and the focus of this study is to find out the better process between DMF and UF for the pretreatment of low turbidity seawater. The UF process exhibited a good performance to produce qualified RO feed water and coagulation added the removal of aromatic organics and better resistance to the membrane fouling. However the DMF process could not make RO feed water to satisfy the SDI standard and variations in operation conditions did not change the product water quality. In order to enhance the performance of DMF process, a multi-pass design or an improved coagulation strategy for low turbidity water should be necessary, which makes a proper design of DMF more difficult. Therefore, UF can be a better option for the pretreatment of low turbidity seawater. © 2011 Desalination Publications. All rights reserved.

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