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Arctic Primary Aerosol Production Strongly Influenced by Riverine Organic Matter
Park, Jiyeon,Dall’Osto, Manuel,Park, Kihong,Kim, Jung-Hyun,Park, Jongkwan,Park, Ki-Tae,Hwang, Chung Yeon,Jang, Gwang Il,Gim, Yeontae,Kang, Sujin,Park, Sanghun,Jin, Yong Keun,Yum, Seong Soo,Simó American Chemical Society 2019 Environmental science & technology Vol.53 No.15
<P>The sources of primary and secondary aerosols in the Arctic are still poorly known. A number of surface seawater samples-with varying degrees of Arctic riverine and sea ice influences-were used in a sea spray generation chamber to test them for their potential to produce sea spray aerosols (SSA) and cloud condensation nuclei (CCN). Our interdisciplinary data showed that both sea salt and organic matter (OM) significantly influenced the SSA production. The number concentration of SSA in the coastal samples was negatively correlated with salinity and positively correlated with a number of OM tracers, including dissolved and chromophoric organic carbon (DOC, CDOM), marine microgels and chlorophyll <I>a</I> (Chl-<I>a</I>) but not for viral and bacterial abundances; indicating that OM of riverine origin enhances primary aerosol production. When all samples were considered, transparent exopolymer particles (TEP) were found to be the best indicator correlating positively with the ratio number concentration of SSA/salinity. CCN efficiency was not observed to differ between the SSA from the various samples, despite differences in organic characteristics. It is suggested that the large amount of freshwater from river runoff have a substantial impact on primary aerosols production mechanisms, possibly affecting the cloud radiative forcing.</P> [FIG OMISSION]</BR>
Transformation of dissolved organic matter in a constructed wetland
Jongkwan Park,Mijin Choi,Jaeweon Cho,Kyongmi Chon 대한환경공학회 2018 Environmental Engineering Research Vol.23 No.4
This study investigated the transformation of dissolved organic matter (DOM) in a free-water surface flow constructed wetland. Pyrolysis gas chromatography-mass spectrometry (Py-GC/MS) coupled with preparative high-performance liquid chromatography (prep-HPLC) was used to analyze the compositions of biopolymers (polysaccharides, amino sugars, proteins, polyhydroxy aromatics, lipids and lignin) in DOM according to the molecular size at three sampling points of the water flow: inflow, midflow, and outflow. The prep-HPLC results verified the decomposition of DOM through the decrease in the number of peaks from three to one in the chromatograms of the sampling points. The Py-GC/MS results for the degradable peaks indicated that biopolymers relating to polysaccharides and proteins gradually biodegraded with the water flow. On the other hand, the recalcitrant organic fraction (the remaining peak) in the outflow showed a relatively high concentration of aromatic compounds. Therefore, the ecological processes in the constructed wetland caused DOM to become more aromatic and homogeneous. This indicated that the constructed wetland can be an effective buffer area for releasing biochemically stable DOM, which has less influence on biological water quality indicators, e.g., biochemical oxygen demand, into an aquatic ecosystem.
Evaluating membrane fouling potentials of dissolved organic matter in brackish water
Park, Sanghun,Nam, Taewoo,You, Jeongyeop,Kim, Eun-Sik,Choi, Ilhwan,Park, Jongkwan,Cho, Kyung Hwa Elsevier 2019 Water research Vol.149 No.-
<P><B>Abstract</B></P> <P>Isolating dissolved organic matter (DOM) is a preliminary step that improves the accuracy of its characterization. In this study, DOM in brackish water was clearly separated and evaluated by multiple characterization analyses. The sample was divided into three fractions by preparative high-performance liquid chromatography (preparative HPLC) according to molecular size. The homogeneity of each fraction was estimated by analytical size exclusion chromatography (SEC) and fluorescence excitation-emission matrix (FEEM). Pyrolysis gas chromatography-mass spectrometry (Py-GC/MS) and liquid chromatography-organic carbon detection (LC-OCD) were used to characterize the physicochemical properties of each fraction. Py-GC/MS revealed that Fraction 1 consisted of evenly distributed organic matter in order polysaccharides, proteins, polyhydroxy aromatics, lignins, and lipids. However, Fraction 2 was primarily composed of dominant lipids and low portion of proteins, and Fraction 3 was composed predominantly of lignins and lipids. The LC-OCD results showed that Fractions 1 and 2 had similar organic carbon (OC) compositions: a humic substance (ca. 37%), building blocks (ca. 10%), and neutrals (ca. 37%), whereas Fraction 3 contained a high proportion of neutrals (62%). In the fouling experiments, the distinct DOM characteristics in each fraction resulted in different declining flux behaviors, ranked as: Fraction 2 > Fraction 1 > Fraction 3.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Brackish water DOM was fractionated by preparative HPLC. </LI> <LI> LC-OCD and Py-GC/MS evaluated the characteristics of brackish water DOM fractions. </LI> <LI> Effect of DOM characteristics affected to fouling potential in membrane filtration. </LI> <LI> The high proportion of lipids showed highest fouling potential. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Park, Jongkwan,Lee, Sungyun,You, Jeongyeop,Park, Sanghun,Ahn, Yujin,Jung, Woonggyu,Cho, Kyung Hwa Elsevier 2018 The Science of the total environment Vol.642 No.-
<P><B>Abstract</B></P> <P>Resistance-in-series models have been applied to investigate fouling behavior. However, it is difficult to model the influence of morphology on fouling behavior because resistance is indirectly calculated from the water flux and transmembrane pressure. In this study, optical coherence tomography (OCT) was applied to evaluate the resistance of the fouling layer based on fouling morphology. Sodium alginate, humic acid, and bovine serum albumin (BSA) with high salts concentrations (conductivity: 23 mS/cm) were used as model foulants. At the same total fouling resistance, BSA showed the highest cake layer thickness (BSA (114.5 μm) > humic acid (53.5 μm) > sodium alginate (20.0 μm)). However, a different order was found for the cake layer resistance (BSA > sodium alginate > humic acid). This indicates that fouling thickness is not correlated with cake layer resistance. According to the Carman–Kozeny equation, fouling layer porosity decreased in the following order: humic acid (0.30) > BSA (0.21) > sodium alginate (0.20). In addition, we provided a specific value that was calculated using the ratio between the fouling thickness and cake layer resistance. The results show that alginic acid induced a stronger cake layer resistance, despite its thin fouling layer, whereas BSA showed a relatively low potential for inducing cake layer resistance. The results obtained in this study could be used for estimating and predicting fouling behavior.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Property of fouling layer was investigated by the membrane resistance value and fouling thickness. </LI> <LI> Humic acid, sodium alginate, and BSA fouling layers in brackish water were visualized via OCT. </LI> <LI> Gel/cake layer and adsorbed/pore blocking fouling types were distinguished by 2D OCT images. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Park, Minho,Park, Jongkwan,Lee, Eunkyung,Khim, Jeehyeong,Cho, Jaeweon Informa UK (Taylor Francis) 2016 Desalination and Water Treatment Vol.57 No.44
<P>To minimize scale formation potential in the applications of reverse osmosis (RO) membranes as a pretreatment unit, relatively loose nanofiltration (NF) membrane systems coupled with ultrafiltration (UF) were used to remove divalent ions from seawater. However, the UF did not reject any ions because of pore size. The rejection of divalent ions by NF was in order of sulfate (>95%), magnesium (>60%), and calcium (>30%) in every rejection experiment based on water recovery rate (40, 50, 60, 70, and 80%). In the UF/NF/RO hybrid pilot system, most of the divalent (>99%) and the monovalent (>97%) ions were effectively rejected with slightly increased divalent ion rejection compared to the UF/RO system. Seawater temperature influenced rejection of ions with regards to either the diffusion- or convection-dominant transport of ions through the membrane pores. Electric power consumption was also compared between the UF/NF/RO process and the UF/RO process. For different salinity conditions (28,000 and 45,000mg/L of total dissolved solids), the lowest energy consumption by NF/RO was 3.3 and 6kWh/m(3) with recovery of 80% for NF and 40% for RO, respectively.</P>
Park, Jongkwan,Cho, Kyung Hwa,Lee, Eunkyung,Lee, Sungyun,Cho, Jaeweon Elsevier 2018 Science of the Total Environment Vol.635 No.-
<P><B>Abstract</B></P> <P>There is a growing interest in the removal of pharmaceuticals from wastewater because pharmaceuticals have potential ecotoxicological effects. Among several removal mechanisms, the sorption of pharmaceuticals to sediment organic matter is an important mechanism related to the mobility of pharmaceuticals. This study investigated the sorption of pharmaceuticals to soil organic matter (SOM) by electrostatic interactions. SOM located on the surface of soil/sediment generally has a negative charge because of the functional groups present (i.e., carboxylic and phenolic groups). Thus, the electrical characteristics of SOM can induce electrical attraction with positively charged chemical compounds. In this study, SOM was extracted from soils under different aquatic plants (<I>Acorus</I> and <I>Typha</I>) in a constructed wetland in Korea. Experiments were carried out with the following three pharmaceuticals with different electrical characteristics at pH 7: atenolol (positive charge; pKa 9.5), carbamazepine (neutral; no pKa), and ibuprofen (negative charge; pKa 4.9). The SOM in the <I>Acorus</I> pond had a higher hydrophobicity and electrical charge density than that in the <I>Typha</I> pond. Regarding the sorption efficiency between SOM and charged pharmaceuticals, atenolol showed highest sorption efficiency (~60%), followed by carbamazepine (~40%) and ibuprofen (<~30%). In addition, the removal efficiency of the targeted pharmaceuticals in the constructed wetland was estimated by comparing the concentrations of the pharmaceuticals at sampling points with flowing water. The results showed that the removal efficiency of atenolol and carbamazepine was almost 50%, whereas that of ibuprofen was only ~10%. A comparison of the results of lab-scale and field experiments showed that electrostatic interaction is one of the major pharmaceutical removal mechanisms in a constructed wetland.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Sorption of pharmaceuticals to SOM by electrostatic interaction is studied. </LI> <LI> SOM was sampled from soils under aquatic plants <I>Acorus</I> and <I>Typha</I> in a wetland. </LI> <LI> The experiments used three pharmaceuticals: atenolol, carbamazepine, and ibuprofen. </LI> <LI> Atenolol had highest sorption efficiency, followed by carbamazepine and ibuprofen. </LI> <LI> Electrostatic interaction is a major removal mechanism in constructed wetlands. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>