Yunho Lee

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

Transformation of atenolol (ATN), a micropollutant containing a secondary (2o) amine moiety, can be significantly enhanced in water treatment with sequential and combined use of chlorine and UV (chlorine/UV) through photolysis of the N-Cl bond. This study investigated the transformation kinetics, products, and mechanisms of the amine moiety of ATN...

This study investigated the degradation and deactivation of an extracellular ampicillin resistance gene (ampR) encoded in plasmid pUC19 during exposure to UV254, •OH (generated by UV>290/H2O2), and combined exposure to UV254 and •OH (SO4•−) using UV254/H2O2 and UV254/S2O8²⁻. The degradation rates of ampR measured by quantitative polymerase chain re...

The occurrence and fate of the popular pharmaceutical gabapentin (GBP) in the urban water cycle were investigated with a focus on its transformation during water chlorination. GBP was detected in all samples with average concentrations of 1285 ng/L (n = 24) for wastewater effluent, 304 ng/L for river water (n = 22), and 180 ng/L for drinking water...

This study investigated the UV254 photolysis of free available chlorine and bromine species in water. The intrinsic quantum yields for •OH and X• (X=Cl or Br) generation were determined by model fitting of formaldehyde formation using a tert-butanol assay to be 0.61/0.45 for HOCl/OCl⁻ and 0.32/0.43 for HOBr/OBr⁻, respectively. The steady-state •OH...

Degradation kinetics of antibiotic resistance genes (ARGs) by free available chlorine (FAC), ozone (O3), and UV254 light (UV) were investigated in phosphate buffered solutions at pH 7 using a chromosomal ARG (mecA) of methicillin-resistant Staphylococcus aureus (MRSA). For FAC, the degradation rates of extracellular mecA (extra-mecA) were accelerat...

Objectives : This study aimed to evaluate the removal efficiency of trace organic contaminants (TrOCs) in UV-based advanced oxidation processes (AOPs) as an alternative to the post-ozonation process in a drinking water treatment plant (DWTP) in the downstream of Nakdong River. The results are expected to be utilized as basic data for modernizing ag...

This research developed and optimized innovative, cost-effective methods to quantify extractable total per- and polyfluoroalkyl substances (PFAS) in water, overcoming limitations of existing techniques by integrating persulfate preoxidation with subsequent solid phase extraction (SPE), followed by chemical defluorination using sodium biphenyl (SBP...

The abatement of micropollutants by ozonation can be accurately calculated by measuring the exposures of molecular ozone (O3) and hydroxyl radical (•OH) (i.e., ∫[O3]dt and ∫[•OH]dt). In the actual ozonation process, ∫[O3]dt values can be calculated by monitoring the O3 decay during the process. However, calculating ∫[•OH]dt is challenging in the fi...

This study investigated the occurrence, removal rate, and potential risks of 43 organic micropollutants (OMPs) in four municipal wastewater treatment plants (WWTPs) in Korea. Results from two-year intensive monitoring confirmed the presence of various OMPs in the influents, including pharmaceuticals such as acetaminophen (pain relief), caffeine (st...

To predict the fate of micropollutants (MPs) in the anaerobic zone at the lab and full-scale levels, anaerobically biological removal (adsorption and biodegradation) of 40 MPs was performed. Among the 40 MPs in the full-scale anaerobic tank, estriol and acetaminophen showed the highest total removal efficiencies in the anaerobic zone (∼100 %). In b...

Organic micropollutants present in effluents of wastewater treatment plants (WWTPs) can negatively affect the quality of receiving waters or drinking water sources. The present work monitored the concentration of bioactive chemicals using a battery of in vitro bioassays in 14 WWTP effluents, 2 effluent-dominant streams, and 5 river waters in the Na...

Effluent from wastewater treatment plants is considered an important source of micropollutants (MPs) in aquatic environments. However, monitoring MPs in effluents is often inefficient owing to the variety in their types. Thus, this study derived marker constituents to estimate the behavior of MPs in each cluster using the self-organizing map (SOM),...

This study aimed to implement an extensive prediction model for the fate of micropollutants (MPs) in wastewater treatment plants (WWTPs). Five WWTPs equipped with seven different biological treatment processes were monitored from 2020 to 2022 with three to four sampling events in each year, and 27 datasets for 20 MPs were collected. Among these dat...

The composition of the wastewater matrix influences the oxidation potential of ozonation, a technique widely recognized efficient removal of micropollutants. Here, we developed a chemical kinetic model to determine the ozone dose required to minimize bromate production in wastewater containing bromine ions while achieving target removal rates. In w...

Gravity-driven membrane (GDM) filtration has been proposed as an alternative to sand filtration for drinking water treatment, but its low membrane flux and poor permeate quality hinder its widespread application. This study investigated the effect of pre-ozonation (with various dosages and application timings) on membrane flux, fouling layer charac...

Ozonation, a viable option for improving wastewater effluent quality, requires process optimization to ensure the organic micropollutants (OMPs) elimination and disinfection under minimized byproduct formation. This study assessed and compared the efficiencies of ozonation (O3) and ozone with hydrogen peroxide (O3/H2O2) for 70 OMPs elimination, ina...

Electronic waste (e-waste) is the world's fastest-growing type of waste, with lighting accounting for 9% of the total. Light-emitting diodes (LEDs) are composed of the most concentrated critical elements (Ag and Au) and recovery of these metals could generate economic benefits and reduce the burdens of environmental pollution; nevertheless, the abs...

Cationic amphipathic structures are often utilized in natural membrane-active host-defense peptides. Negatively charged surface membranes of rapidly proliferating bacterial and cancer cells have been targeted by various synthetic peptides and peptidomimetics adopting the structural motif. Herein, we synthesized a set of conjugates composed of catio...

Ferrate (Fe(VI)) is a novel oxidant that can be used to mitigate disinfection byproduct (DBP) precursors. However, the reaction of Fe(VI) with organic nitrogen, which is a potential precursor of potent nitrogenous DBPs, remains largely unexplored. The present work aimed to identify the kinetics and products for the reaction of Fe(VI) with primary a...

Effluents of wastewater treatment plants (WWTPs) contain various organic micropollutants, some of which can exert negative effects on the quality of receiving waters or drinking water sources. This study monitored two full-scale WWTPs in Korea for the occurrence and removal of bioactive chemicals for a one-year period using a battery of in vitro bi...

Improving access to safe drinking water in developing countries is still a challenge and Gravity-Driven Membrane (GDM) filtration systems may be a sustainable solution. Two rural schools in West Java Indonesia were studied, one as a control site and another having an installed GDM system. Chemical and microbiological water quality data were collect...

This study investigated antibiotic resistance gene (ARG) degradation kinetics in wastewaters during bench- and full-scale treatment with UV light and chlorine─with the latter maintained as free available chlorine (FAC) in low-ammonia wastewater and converted into monochloramine (NH2Cl) in high-ammonia wastewater. Twenty-three 142-1509 bp segments (...

In this study, a novel MoS2/Bi2MoO6 composite photocatalyst, which was further sensitized using graphene quantum dots (GQDs), was developed to realize multiple photocatalytic applications in antibiotic remediation and Cr(VI) reduction. A simple chemical mixing procedure was used to prepare the GQD-MoS2/BMO composite photocatalyst, which was compreh...

Gravity-driven membrane (GDM) filtration is currently limited by the relatively low permeate flux and poor water quality. This study was aimed to investigate the effects of prechlorination (3 and 5 mgCl2/L) on the permeate flux and water quality in GDM filtration by analyzing the compositions and morphologies of the fouling layer and by evaluating...

This study investigated the reaction kinetics and elimination efficiency of eleven synthetic musks during ozonation and UV254nm-based, advanced oxidation processes (AOPs). The synthetic musks containing olefin moieties with electron-donating alkyl substituents (OTNE and AMBT) showed high reactivity toward ozone (k ≥ 3.7 × 105 M-1 s-1) and free avai...

Conventional wastewater treatment plants (WWTPs) do not fully remove micropollutants. Enhanced treatment of sewage effluents is being considered or implemented in some countries to minimize the discharge of problematic micropollutants from WWTPs. Representative enhanced sewage treatment technologies for micropollutant removal were reviewed, includi...

The frequent detection and occurrence of micropollutants (MPs) in aquatic ecosystems has raised public health concerns worldwide. In this study, the behavior of 50 MPs was investigated in three different domestic wastewater treatment plants (WWTPs). Furthermore, the Kruskal-Wallis test was used to assess the geographical and seasonal variation of M...

Chlorine dioxide (ClO2) applications to drinking water are limited by the formation of chlorite (ClO2-) which is regulated in many countries. However, when ClO2 is used as a pre-oxidant, ClO2- can be oxidized by chlorine during subsequent disinfection. In this study, a kinetic model for the reaction of chlorine with ClO2- was developed to predict t...

This study investigated the reaction kinetics and degradation efficiency of methylparaben and its halogenated products (Cl-, Br-, Cl,Cl-, Br,Cl-, and Br,Br-methylparabens) during ozonation and UV254/H2O2 treatment. Second-order rate constants for reactions of the parabens with ozone and •OH were kO3 = 10⁷ – 10⁸ M⁻¹ s⁻¹ and k•OH = (2.3 – 4.3)×10⁹ M⁻...

A combined process of coagulation and powdered activated carbon (PAC) was tested as an alternative primary wastewater treatment option to remove dissolved organic matter and organic micropollutants (OMPs). Bench-scale experiments were performed using three coagulants (Al2(SO4)3, PACl, and FeCl3) and four PAC materials (SPC, F400, BL, and SPO). The...

In this study, a thin-film composite (TFC) loose nanofiltration (NF) membrane comprising a poly(piperazine-amide) (PPA) active layer was successfully fabricated by the electrospray interfacial polymerization (EIP) method. Sulfonated graphene oxide (SGO) and magnetite-decorated SGO (MGO) were synthesized and individually embedded in the polymer matr...

This study investigated the reaction kinetics and elimination efficiency of eleven synthetic musks during ozonation and UV254nm-based, advanced oxidation processes. The synthetic musks containing olefin moieties with electron-donating alkyl substituents such as octahydro tetramethyl naphthalenyl ethanone (OTNE) and ambrettolide (AMBT) showed high r...

Ultraviolet (UV) radiation alone or in combination with other oxidation processes is increasingly being considered for water disinfection because of stringent regulatory requirements for pathogen inactivation. To fulfill this requirement, an appropriate UV dose or fluence (mJ/cm²) is applied to combat enteric viruses in surface or treated water. Th...

A sulfonated graphene oxide (SGO) composite loose nanofiltration membrane (LNM) with high water permeance was fabricated by the electrospray interfacial polymerization (EIP) method to treat saline dye wastewater. The SGO incorporated EIP membrane showed enhanced characteristics and performances even with a small amount of nanoparticles (0.04 g per...

Ferrate (Fe(VI)), a promising water treatment oxidant, can be used for micropollutant abatement or disinfection byproduct mitigation. However, knowledge gaps remain concerning the interaction between Fe(VI) and dissolved organic matter structures, notably primary amines. This study investigated degradation kinetics and products of several aliphatic...

The goal of this study was to investigate the occurrence and removal of 52 organic micropollutants (OMPs) during each wastewater treatment step in a full-scale wastewater treatment plant (WWTP). Pharmaceuticals such as metformin, acetaminophen, caffeine, ibuprofen, cimetidine and naproxen were found with high average concentrations in the influent....

This study demonstrates that Cu(II) can significantly enhance the decomposition rate of bromamines. Apparent second order rate constants of 2.31 ± 0.01 M⁻¹s⁻¹ and 0.36 ± 0.01 M⁻¹s⁻¹ at pH 7.5 were determined for the reaction of Cu(II) with bromamines and the self-decomposition of bromamines, respectively. Increasing the pH from 6.0 to 8.5, the rate...

Objectives:In the case of pharmaceuticals with high possibility of inflow into the large drinking water treatment plant (DWTP) located in the downstream of the Nakdong River, we tried to evaluate the removal efficiency of pharmaceuticals in the both ozone (O3) and the UV/H2O2 treatment as an alternative of post-O3 process. It was intended to be use...

Due to the large-scale production and use of synthetic chemicals in industralized countries, various chemicals are found in the aquatic environment, which are often termed as micropollutants. Effluents of municipal wastewater treatment plants (WWTPs) have been identified as one of the major sources of these micropollutants. In this article, the cur...

Multitarget engagement is considered an effective strategy to overcome the threat of bacterial infection, and antimicrobials with multiple mechanisms of action have been successful as natural chemical weaponry. Here, we synthesized a library of photosensitizer-peptoid conjugates (PsPCs) as novel antimicrobial photodynamic therapy (aPDT) agents. The...

Degradation and deactivation kinetics of an antibiotic resistance gene (ARG) by ozone (O3) and free available chlorine (FAC) were investigated in phosphate-buffered solutions at pH 7 for O3 (in the presence of tert-butanol), and pH 6.8 or 8.1 for FAC. We used a plasmid (pUC19)-encoded ampicillin resistance gene (ampR) in both extracellular (e-) and...

UV254 irradiation disinfection is a commonly used method to inactivate pathogenic viruses in water and wastewater treatment. Model prediction method can serve as a pre-screening tool to quickly estimate the effectiveness of UV254 irradiation on emerging or unculturable viruses. In this study, an improved prediction model was applied to estimate UV2...

The degradation of ethanolamine (ETA), a recalcitrant pollutant containing a primary amine moiety, can be significantly enhanced in a water treatment with chlorination followed by UV (UV/chlorine) via photolysis of the N-Cl bond of monochloro- (N-Cl ETA) and dichloro-ethanolamine (N-Cl2 ETA) which are formed from the reaction of chlorine with ETA....

Gravity-driven membrane (GDM) filtration is one of the promising technologies for decentralized water treatment systems due to its low cost, simple operation, and convenient maintenance. The objective of this study was to evaluate the permeability of submerged GDM filtration with three different membranes, i.e., polyethersulfone and polyvinylidene...

Recovery of gold from electronic wastes, particularly waste printed circuit boards (WPCBs), has received significant attention due to its high gold content and economic value. This study reports a novel method for efficient and selective recovery of gold from WPCBs using an integrated chlorate leaching and chitosan-based bioadsorption. The experime...

The World Health Organization Global Action Plan recommends integrated surveillance programs as crucial strategies for monitoring antibiotic resistance. Although several national surveillance programs are in place for clinical and veterinary settings, no such schemes exist for monitoring antibiotic-resistant bacteria in the environment. In this tra...

Loose nanofiltration (NF) membrane with excellent dye rejection and high permeation of inorganic salt is required to fractionate dye/salt mixture in dye wastewater treatment. In this study, we fabricated the loose NF membrane by using the electrospray interfacial polymerization (EIP) method. It is a novel and facile interfacial polymerization metho...

N,N-Dimethylhydrazine ((CH3)2–N–N–) compounds in water produce toxic N-nitrosodimethylamine (NDMA) during ozonation, so need removing from water before ozonation. Chlorination can degrade N,N-dimethylhydrazines to give products that do not form NDMA during ozonation, but the chemistry is poorly understood. We studied the kinetics of and mechanisms...

The influents and effluents of coastal flow-through aquacultures in Korea were monitored for four selected antibiotics (amoxicillin-AMX, florfenicol-FLO, oxolinic acid-OXO, and oxytetracycline-OTC). A number of 177 samples were obtained from 16 aquaculture facilities for a monitoring period of two years. OTC was detected in 93 samples with a median...

Oxidative treatment of iodide-containing waters can lead to a formation of potentially toxic iodinated disinfection byproducts (I-DBPs). Iodide (I⁻) is easily oxidized to HOI by various oxidation processes and its reaction with dissolved organic matter (DOM) can produce I-DBPs. Hydrogen peroxide (H2O2) plays a key role in minimizing the formation o...

Recovery of gold from electronic waste (e-waste) has received significant attention due to its high economic value. This study reports glutaraldehyde-crosslinked chitosan (GCC) beads as highly efficient bioadsorbents for the separation of auric ions (Au(III)) from acidic e-waste leaching solutions. With increasing extent of glutaraldehyde-crosslink...

This paper presents ferrate(VI) (FeVIO42-, FeVI) oxidation of a wide range of sulfonamide antibiotics (SAs) containing five- and six-membered heterocyclic moieties (R) in their molecular structures. Kinetics measurements of the reactions between FeVI and SAs at different pH (6.5 – 10.0) give species-specific second-order rate constants, k5 and k6 o...

This work investigated degradation (measured by qPCR) and biological deactivation (measured by culture-based natural transformation) of extra- and intracellular antibiotic resistance genes (eARGs and iARGs) by free available chlorine (FAC), NH2Cl, O3, ClO2, and UV light (254 nm), and of eARGs by •OH, using a chromosomal ARG ( blt) of multidrug-resi...

This study investigated the influence of membrane property and feed water organic matter quality on the permeate flux and water quality during gravity-driven membrane (GDM) filtration. GDM filtration was continuously carried out over 500 days at hydrostatic pressure of 65 mbar in dead-end mode without any back-flushing or membrane cleaning. Three u...

The photodemethylation (PD) is a dominant degradation process of methylmercury (MeHg) in sunlit surface seawater, leading to the decreased bioaccumulation of MeHg in pelagic organisms. This study investigated the PD rate constant of MeHg in artificial estuarine water under UV-A irradiation, with the addition of various types of dissolved organic ma...

When the methylparabens (MPs) remaining in the raw water is introduced into the water treatment process, halogenated parabens are produced by reacting with chlorine. In this study, biodegradation characteristics of halogenated parabens in biological activated carbon (BAC) process were evaluated. The biodegradability of methylparaben (MP) and five h...

Oxidative treatment of iodide-containing waters can form iodinated disinfection by-products (I-DBPs) that are more toxic than the regulated DBPs. To better understand the fate of iodine during water treatment with ferrate(VI), kinetics, products, and stoichiometries for the reactions of ferrate(VI) with iodide (I⁻) and hypoiodous acid (HOI) were de...

In this study, methyl paraben (MP), ethyl paraben (EP), propyl paraben (PP), and butyl paraben (BP) were analyzed to identify their occurrence characteristics at various sampling sites (the effluent from the wastewater treatment plant, the main stream and tributaries to which the effluent is introduced) in the Nakdong River basin during various sam...

To better understand the elimination of transforming activity of antibiotic resistance genes (ARGs), this study determined deactivation of transforming activity of an ARG (in Escherichia coli as a host) and...

The presence of toxic microcystins in algal-impacted surface waters is a concern for drinking water quality management. In this study, the potential of ferrate(VI) to eliminate microcystins during drinking water treatment was assessed by investigating reaction kinetics, reaction sites, transformation products, and toxicity changes for the oxidation...

The reaction kinetics, products, and pathways of methylparaben (MeP) during water chlorination with and without bromide (Br-) were investigated to better understand the fate of parabens in chlorinated waters. During the chlorination of MeP-spiked waters without Br-, MeP was transformed into mono-Cl-MeP and di-Cl-MeP with apparent second-order rate...

The potential of ferrate(VI) to oxidize algal-derived taste and odor (T&O) compounds during water treatment was assessed by investigating the reaction kinetics of ferrate(VI) with selected T&O compounds. Apparent second-order rate constants (kapp) were determined in phosphate buffered waters in the pH range of 6–9. The olefinic T&O compounds show a...