Chulmin Lee

Gwangju Institute of Science and Technology · School of Environmental Science and Engineering

Fouling in seawater reverse osmosis (SWRO) is a crucial parameter for a long-term operation. This study investigated a standard configuration wherein energy recovery device (ERD) being placed in the front of the first stage, an inter-stage ERD (ISERD) configuration wherein the ERD booster being placed in-between the two stages, and ISERDISD configu...

Understanding the insightful impact of divalent cations mass transport on the complex organic fouling of forward osmosis (FO) membrane is vital when seawater/brine is utilized in a FO hybrid process. Our works deeply focused on quantifying the influence of divalent cations on not only critical flux but also the organic fouling mechanism. The presen...

Pressure-assisted forward osmosis (PAFO) process has been studied in recent years to overcome the low water productivity in FO-RO hybrid seawater desalination. Our research group demonstrated a pilot-scale PAFO-RO plant for seawater desalination operations using secondary treated wastewater and real seawater. A pretreatment stage of mesh tube filte...

The wastewater–seawater (WW-SW) integrated reverse osmosis (RO) process has gained much attention in and out of academia due to its energy saving capability, economic benefits, and sustainability. The other advantage of this process is to reduce boron concentration in the RO permeate that can exclude the post-treatment process. However, there are m...

Perm-selectivity consisting of water flux Jw and solute flux Js or in form of Js/Jw ratio is an important parameter of designing Forward Osmosis (FO) membrane as it indicates the membrane performance and how much solute replenishment over the extracted pure water from the feed solution. Parameter Js/Jw ratio is dependent on hydrodynamic condition i...

The number of chronic renal disease patients has shown a significant increase in recent decades over the globe. Hemodialysis is the most commonly used treatment for renal replacement therapy (RRT) and dominates the global dialysis market. As one of the most water-consuming treatments in medical procedures, hemodialysis has room for improvement in r...

Roughing filters (coarse media filtration) are a type of porous media filters used as pretreatment systems when the raw water contains a large amount of suspended particles and organic matter. Mesh tube filter media, roughing filter media composed of LDPE, are used in the process of removing suspended particles in wastewater treatment. In this stud...

Roughing filters are types of porous media filter used in pretreatment systems where the raw water contains a large amount of suspended particles (SPs) and organic matter. Mesh tube filtration (MTF) media are roughing-filter media composed of low-density polyethylene used for SP removal during wastewater treatment. In this study, we present an impr...

The forward osmosis-reverse osmosis (FO-RO) hybrid process has been extensively researched as part of attempts to reduce the high energy consumption of conventional seawater reverse osmosis in recent years. FO operating conditions play a substantial role in the hybrid process, dictating not only the performance of the entire system but also the pro...

A strategy of using critical fluxes to control organic fouling of polyamide thin film composite (PA-TFC) forward osmosis (FO) membranes during wastewater reclamation was developed for FO mode. This work was a comprehensive investigation with various organic foulants covering complex mixtures as well as single foulants. The foulants were alginate (A...

Uniform flow distribution is a significant parameter for designing pressurized membrane modules because non-uniform flow distribution can cause serious local flux and fouling problems within a module. Thus, this study investigated the fluid behavior with regards to the evenness of water distribution using newly designed inlet distributors in the in...

Conventional researches about ion exchange membrane have been aimed at improving physical properties through structural optimization or introduction of heterogeneous materials into commercial materials. This approach is fundamentally difficult to improve the performances of the electrochemical energy devices. In this study, we synthesized state-of-...

A forward osmosis membrane based on graphene oxide (GO) nanosheets cooperatively cross-linked by ethylenediamine (EDA) and poly(acrylic acid) (PAA) is proposed. While the GO/EDA membrane has the advantages of a higher water flux compared to the pristine GO membrane, it shows a significantly decreased salt rejection. The EDA molecules which bonded v...

A forward osmosis membrane consisting of graphene oxide (GO) nanosheets cooperatively cross-linked by ethylenediamine (EDA) molecule and poly(acrylic acid) (PAA) polymer chain is proposed. Desirable GO-based nanocomposite membrane must satisfy the conflicting requirements of high water flux and salt rejection simultaneously, which is yet to be achi...

This study analyzes the velocity and pressure incurred by protruding shapes installed within the inlet part of a pressurized membrane module during operation to determine the fluid flow distribution. In this paper, to find the flow distribution within a module, it investigates the velocity and pressure values at cross-sectional and outlet planes, a...

Due to the improved dilution of draw streams, employing pressure-assisted forward osmosis (PAFO) to the hybrid system of forward osmosis (FO) followed by reverse osmosis (RO) for seawater desalination has been expected to reduce the overall economics. However, replacing FO with PAFO causes an additional energy cost in the seawater dilution step whi...

Forward osmosis (FO) membranes fall into the category of non-porous membranes, based on the assumption that water and solute transport occur solely based on diffusion. The solution-diffusion (S-D) model has been widely used in predicting their performances in the co-existence of hydraulic and osmotic driving forces, a model that postulates the hydr...

Forward osmosis spiral wound membrane (SWM) element has a modified envelope geometry equipped with central glue line and blocked central tube to accommodate forward osmosis process. Due to modified module structure, water channel inside modified SWM element creates unique flow behaviors and affects performance of modified SWM element. However, rese...

This paper investigated the streamline, velocity vector, and velocity and pressure profiles of fluid to find out the potential of cleaning by backwashing and channel washing at membrane pores and inner surface of inside-out filtration pressurized hollow fiber membrane using computational fluid dynamics simulation. The results of streamline in the m...