Jaesang Lee

Korea University, Sŏul, Seoul, South Korea

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Publications (46)229.07 Total impact

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    ABSTRACT: A substrate-immobilized (SI) TiO2 nanofiber (NF) photocatalyst for multiple uses was prepared through electrospinning and hot pressing. The rate of furfuryl alcohol degradation under UV irradiation was found to be the highest when the anatase to rutile ratio was 70:30; the rate did not linearly increase as a function of the NF film thickness, mainly due to diffusion limitation. Even after eight repeated cycles, it showed only a marginal reduction in the photocatalytic activity for the degradation of cimetidine. The effects of pH and different organic matter characteristics on the photodegradation of cimetidine (CMT), propranolol (PRP), and carbamazepine (CBZ) were investigated. The pH-dependence of the photocatalytic degradation rates of PRP was explained by electrostatic interactions between the selected compounds and the surface of TiO2 NFs. The degradation rates of CMT showed the following order: deionized water > l-tyrosine > secondary wastewater effluent (effluent organic matter) > Suwannee River natural organic matter, demonstrating that the characteristics of the dissolved organic matter (DOM) can affect the photodegradation of CMT. Photodegradation of CBZ was affected by the presence of DOM, and no significant change was observed between different DOM characteristics. These findings suggest that the removal of CMT, PRP, and CBZ during photocatalytic oxidation using SI TiO2 NFs is affected by the presence of DOM and/or pH, which should be importantly considered for practical applications. Copyright © 2015 Elsevier Ltd. All rights reserved.
    Water Research 05/2015; DOI:10.1016/j.watres.2015.05.032 · 5.53 Impact Factor
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    ABSTRACT: Carbon nanotubes (CNTs) have been found to activate persulfates (i.e., peroxymonosulfate and peroxydisulfate) into reactive species that are capable of oxidizing organic compounds in water. In the presence of single- or multi-walled CNTs, persulfates effectively degraded phenolic compounds and certain pharmaceuticals. Phenyl derivatives substituted with electron-withdrawing groups, such as benzoic acid and nitrobenzene, were resistant to degradation by the CNT/persulfate system. Based on observations regarding persulfate decomposition and linear sweep voltammetry using a CNT electrode, it has been suggested that persulfates bind onto the surface of CNTs, forming reactive complexes that are immediately decomposed upon reaction with organic compounds. Electron paramagnetic resonance spectroscopy with spin-trapping indicates that these reactive species are distinct from sulfate radical anions or hydroxyl radicals. The CNT-activated persulfate system shows promise as a novel treatment technology for the selective oxidation of organic contaminants in water.
    The Chemical Engineering Journal 04/2015; 266. DOI:10.1016/j.cej.2014.12.065 · 4.32 Impact Factor
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    ABSTRACT: A paper-like photocatalyst was fabricated by electrospraying an N,N′-dimethylformamide (DMF) dispersion of titanium dioxide (TiO2) nanoparticles (NPs) on a poly(vinylidene fluoride) nanofiber (PVDF NF) mat prepared by electrospinning. Morphological studies revealed that the TiO2 NPs uniformly deposited as clusters on the surface of the PVDF NF mat. The immobilized amount of TiO2 was found to be 2.08, 2.44, 3.80, and 4.73 mg per 45 cm2 of PVDF–TiO2 hybrids for the electrospraying of 10, 20, 40, and 60 ml of TiO2–DMF, respectively. The hybrid photocatalysts were effective in degrading bisphenol A (BPA), 4-chlorophenol (4-CP), and cimetidine (CMT), which dissolved in both deionized water and secondary wastewater effluents, with activity being proportional to the quantity of TiO2 NPs immobilized. For the highest loading amount of TiO2, BPA, 4-CP, and CMT degraded completely within 100, 100, and 40 min of UV irradiation, respectively. Stable photo-oxidation of CMT was maintained through 10 repeated cycles. During these cycles, it was confirmed that there was no loss of TiO2 NPs by inductively coupled plasma optical emission spectrometry. Our results suggest that effective and stable PVDF–TiO2 hybrid photocatalysts can be fabricated on a large scale by combining electrospinning and electrospraying techniques.
    Journal of Hazardous Materials 03/2015; 285. DOI:10.1016/j.jhazmat.2014.12.004 · 4.53 Impact Factor
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    ABSTRACT: A new material was developed and evaluated for the targeted removal of trichlorophenol (TCP) from among potential interferents which are known to degrade removal activity. To achieve TCP-targeted activity, an alginate bead containing nanoscale palladium/zero-valent iron (Pd/nZVI) was coated with a highly hydrophobic oleic acid layer. The new material (Pd/nZVI-A-O) preferentially sorbed TCP from a mixture of chlorinated phenols into the oleic acid cover layer and subsequently dechlorinated it to phenol. The removal efficacy of TCP by Pd/nZVI-A-O was not affected by co-existing organic substances such as Suwannee River humic acid (SRHA), whereas the material without the oleic acid layer (Pd/nZVI-A) became less effective with increasing SRHA concentration. The inorganic substances nitrate and phosphate significantly reduced the reactivity of Pd/nZVI-A, however, Pd/nZVI-A-O showed similar TCP removal efficacies regardless of the initial inorganic ion concentrations. The influence of bicarbonate on the TCP removal efficacies of both Pd/nZVI-A and Pd/nZVI-A-O was not significant. The findings from this study suggest that Pd/nZVI-A-O, with its targeted, constant reactivity for TCP, would be effective for treating this contaminant in surface water or groundwater containing various competitive substrates.
    Journal of Hazardous Materials 03/2015; 293. DOI:10.1016/j.jhazmat.2015.03.021 · 4.53 Impact Factor
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    ABSTRACT: This study evaluates the capacity of various inorganic oxidants (IO4−, HSO5−, S2O82−, H2O2, and BrO3−) to act as alternative electron acceptors for WO3-mediated photocatalytic oxidation. Combination with IO4− drastically increased the rate of photocatalytic degradation of 4-chlorophenol by WO3, while the other oxyanions only negligibly improved the photocatalytic activity. The extent of the photocatalytic performance enhancement in the presence of inorganic oxidants correlated well with the efficiencies for: (1) hydroxylation of benzoic acid as an OH probe, (2) dechlorination of dichloroaceate as a hole scavenger, and (3) water oxidation with O2 evolution. The results suggest that the promoted charge separation primarily causes kinetic enhancement in photocatalytic degradation using the WO3/IO4− system. In marked contrast to the substrate-dependent activity of the photochemically activated IO4− (generating selective IO3), the efficiency of the WO3/IO4− system for photocatalytic degradation did not sensitively depend on the type of target organic compound, which implies the existence of a minor contribution of the photocatalytic reduction pathway associated with the production of IO3 as a secondary oxidant. On the other hand, the insignificant inhibitory effect of methanol as an OH quencher may reveal the possible involvement of SO4− in the improved photocatalytic activity of the WO3/HSO5− system. The alternative use of platinized WO3, where the interfacial electron transfer occurs in a concerted step, achieved a highly accelerated photocatalytic oxidation in the presence of HSO5− and polyoxometalates as electron scavengers. In particular, the surface loading of nanoscale platinum appeared to retard the reaction route for SO4− generation associated with a one-electron transfer.
    Applied Catalysis B Environmental 01/2015; 162:515-523. DOI:10.1016/j.apcatb.2014.07.019 · 7.44 Impact Factor
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    ABSTRACT: Vertically aligned, electrochromic-coloured, amorphous titania nanotube arrays (TNAs) were fabricated using a facile room-temperature, solution-based electrochemical cathodisation method. Rapid cathodisation within 30s converted pristine TNAs into their dark analogues. Compared to their untreated counterparts, the cathodised dark TNAs exhibited significantly enhanced optical absorbance, covering the full spectrum of visible light. Further annealing of the electrochromic coloured amorphous TNAs in a N-2 atmosphere induced their transformation into dark crystalline TNAs, which directly harnessed simulated sunlight for the photocatalytic degradation of organic contaminants, including phenol, ibuprofen, carbamazepine and caffeine. Compared to the pristine crystalline TNAs (annealed in air), the dark crystalline TNAs showed higher optical absorbance, larger charge carrier density, lower electron transport resistance, and an enhancement of 107-131% in degradation kinetics for the target organic contaminants.
    The Chemical Engineering Journal 08/2014; 249:285–292. DOI:10.1016/j.cej.2014.03.111 · 4.32 Impact Factor
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    ABSTRACT: Nanosized zero-valent iron (nFe0) loaded with a secondary metal such as Ni or Cu on its surface was demonstrated to effectively activate periodate (IO4-) and degrade selected organic compounds at neutral pH. The degradation was accompanied by a stoichiometric conversion of IO4- to iodate (IO3-). nFe0 without bimetallic loading led to similar IO4- reduction but no organic degradation, suggesting the production of reactive iodine intermediate only when IO4- is activated by bimetallic nFe0 (e.g., nFe0-Ni and nFe0-Cu). The organic degradation kinetics in nFe0-Ni(or Cu)/IO4- system was substrate dependent: 4-chlorophenol, phenol, and bisphenol A were effectively degraded, whereas little or no degradation was observed with benzoic acid, carbamazepine, and 2,4,6-trichlorophenol. The substrate specificity, further confirmed by little kinetic inhibition with background organic matter, implies the selective nature of oxidant in the nFe0-Ni(or Cu)/IO4- system. The comparison with the photo-activated IO4- system, in which iodyl radical (IO3•) is a predominant oxidant in the presence of methanol, suggests IO3• also as primary oxidant in the nFe0-Ni(or Cu)/IO4- system.
    Environmental Science and Technology 06/2014; 48(14). DOI:10.1021/es5002902 · 5.33 Impact Factor
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    Changwoo Kim · Jaesang Lee · Seunghak Lee ·
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    ABSTRACT: The sorption properties of TiO2 nanoparticles (NPs) on sand were investigated in the presence of Suwannee River humic acid (SRHA) as a surrogate for natural organic matter. SRHA drastically reduced the sorption preference regardless of the initial pH and ionic strength of the solution. Despite the higher SRHA loading onto sand versus the TiO2 NPs, the consequent zeta (ζ)-potential drop was more significant in the TiO2 NPs, indicating that the decreased sorption should be primarily ascribed to the fraction of SRHA sorbed onto the TiO2 NP surfaces. The hindering effect of SRHA on the sorption increased with SRHA concentration, but stabilized at the concentration equivalent to full surface coverage of the TiO2 NPs and sand in the reaction system. Interaction force measurements indicated that SRHA inhibits the approach of the TiO2 NPs to the sand surface, as expected by the Derjaguin-Landau-Verwey-Overbeek calculation. However, the adhesion force of TiO2 NPs to sand was not critically affected by the presence of SRHA. TiO2 NP sorption to natural sand was limited as to the acid-treated sand in the presence of SRHA, implying that the organics dissolved from natural sand might facilitate the transport of TiO2 NPs in aquifers by inhibiting TiO2 NP sorption to aquifer materials.
    Environmental Earth Sciences 05/2014; 73(9):5585-5591. DOI:10.1007/s12665-014-3812-6 · 1.77 Impact Factor
  • Jaesang Lee · Jungwon Kim · Wonyong Choi ·
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    ABSTRACT: This study evaluates the ability of Fe(II)-oxalate complexes for the generation of OH through oxygen reduction and the oxidative degradation of aquatic pollutants under dark aerobic conditions (i.e., with oxygen but without light). The degradation of 4-chlorophenol (4-CP) was rapid in the mixture of Fe(2+) and oxalate prepared using ultrapure water, but was absent without either Fe(2+) or oxalate. The formation of Fe(II)-oxalate complexes enables two-electron reduction of oxygen to generate H2O2 and subsequent production of OH. The significant inhibition of 4-CP degradation in the presence of H2O2 and OH scavenger confirms such mechanisms. The degradation experiments with varying [Fe(2+)], [oxalate], and initial pH demonstrated that the degradation rate depends on [Fe(II)(Ox)2(2-)], but the degree of degradation is primarily determined by [Fe(II)(Ox)2(2-)]+[Fe(II)(Ox)(0)]. Efficient degradation of diverse aquatic pollutants, especially phenolic pollutants, was observed in the Fe(II)-oxalate complexes system, wherein the oxidation efficacy was primarily correlated with the reaction rate constant between pollutant and OH. The effect of various organic ligands (oxalate, citrate, EDTA, malonate, and acetate) on the degradation kinetics of 4-CP was investigated. The highest efficiency of oxalate for the oxidative degradation is attributed to its high capability to enhance the reducing power and low reactivity with OH.
    Journal of hazardous materials 04/2014; 274C:79-86. DOI:10.1016/j.jhazmat.2014.03.056 · 4.53 Impact Factor
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    ABSTRACT: A magnetically recyclable photosensitizing system for harnessing solar energy for water treatment and disinfection is reported. This system comprises C60 aminofullerene as a sensitizer for singlet oxygenation and functionalized mesoporous silica (msu-f SiO2) encapsulating magnetite nanoparticles (msu-SiO2/mag) as a magnetically separable host. Rapid degradation of furfuryl alcohol (FFA) (a singlet oxygen (1O2) probe) under visible-light irradiation along with the kinetic retardation of FFA decomposition in the presence of 1O2 quenchers suggests that the visible-light activity of C60 aminofullerene-derivatized msu-SiO2/mag (C60/msu-SiO2/mag) is related to the photosensitization of 1O2. On the other hand, the use of SiO2 gel and fumed SiO2 as magnetic supports drastically reduced the photosensitized generation of 1O2, which is ascribed to the absence of an ordered pore structure in the alternative silica support, resulting in an uncontrolled growth of Fe3O4 and an aggregation of the fullerenes on the SiO2 gel and fumed SiO2. Significant 1O2 production using C60/msu-SiO2/mag led to the effective oxidation of emerging pharmaceutical contaminants and inactivation of MS-2 bacteriophage under visible-light irradiation. Magnetic recovery and the subsequent reuse of the composite did not cause any significant loss in the photosensitizing activity of C60/msu-SiO2/mag, demonstrating its potential for catalytic applications.
    Carbon 04/2014; 69:92–100. DOI:10.1016/j.carbon.2013.11.065 · 6.20 Impact Factor
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    ABSTRACT: This study evaluates the applicability of TiO2-based photocatalysts for the treatment of pharmaceutical micropollutants in secondary wastewater effluent (SWE). Photolytic experiments using SWEs with different compositions demonstrated that the rates of photocatalytic degradation of acetaminophen and carbamazepine inversely correlated with the concentration of dissolved organic carbon (DOC), regardless of the type of applied light source and initial pharmaceutical concentration. The critical relevance of organic matter to the scavenging behavior of SWE was further verified by assessing the photocatalytic performance as a function of the concentrations of potential effluent-derived quenchers (i.e., NO3−, Cl−, alkalinity, and humic acid). Kinetic comparison of the degradation of trace levels of pharmaceuticals (i.e., caffeine, cimetidine, propranolol, and sulfamethoxazole) using TiO2/UV-A, TiO2/UV-C, and H2O2/UV-C systems revealed that heterogeneous processes showed more significant performance reduction with increasing DOC concentration; this result indicates that organic matter plays dual roles in the scavenging activity of an effluent matrix: (1) OH radical (OH) quenching and (2) active-site coverage. TiO2 surface modifications (i.e., Pt and SiOx loading) accelerated the degradation of all the tested pharmaceuticals in SWEs to a certain degree. Particularly, the relevant altered surface affinity preferentially increased the susceptibility of specific pharmaceuticals to photocatalytic treatment. The presence of the effluent matrix substantially impaired the performance of visible-light-active photocatalysts in most cases. However, photocatalytic pharmaceutical degradation on Pt-doped TiO2, which occurs via direct charge transfer, was much less hindered in SWEs than that on Pt-deposited WO3, which occurs via OH-mediated oxidation.
    Applied Catalysis B Environmental 04/2014; 147:8–16. DOI:10.1016/j.apcatb.2013.08.032 · 7.44 Impact Factor
  • Dong-Hyo Kim · Jaesang Lee · Jungho Ryu · Kitae Kim · Wonyong Choi ·
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    ABSTRACT: This study demonstrates that the production of reactive oxidizing species (e.g., hydroxyl radical (•OH)) during the photolysis of nitrite (NO2(-)) or nitrate (NO3(-)) leads to the oxidative conversion of arsenite (As(III)) to arsenate (As(V)). While the direct UV photolytic oxidation of As(III) was absent, nitrite (20 or 200 μM) addition markedly accelerated the oxidation of As(III) under UV irradiation (λ > 295 nm), which implies a role of NO2(-) as a photosensitizer for As(III) oxidation. Nitrate-mediated photooxidation of As(III) revealed an initial lag phase during which NO3(-) is converted into NO2(-). UV-Photosensitized oxidation of As(III) was kinetically enhanced under acidic pH condition where nitrous acid (HNO2) with a high quantum yield for •OH production is a predominant form of nitrite. On the other hand, alkaline pH that favors the photo-induced transformation of NO3(-) to NO2(-) significantly facilitated the catalytic reduction/oxidation cycling, which enabled the complete oxidation of As(III) at the condition of [As(III)]/[NO2(-)] > 1 and markedly accelerated NO3(-)-sensitized oxidation of As(III). The presence of O2 and N2O as electron scavengers enhanced the photochemical dissociation of NO2(-) via intermolecular electron transfer, initiating the oxidative As(III) conversion route probably involving NO2• and superoxide radical anion (O2•(-)) as alternative oxidants. The outdoor experiment demonstrated the capability of NO2(-) for the photosensitized production of oxidizing species and the subsequent oxidation of As(III) into As(V) under solar irradiation.
    Environmental Science & Technology 03/2014; 48(7). DOI:10.1021/es500001q · 5.33 Impact Factor
  • Jaesang Lee · Jungwon Kim · Wonyong Choi ·

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    ABSTRACT: Using nitrene chemistry, catechol functionalized aziridinofullerenes (CAC60) were synthesized by reacting N-(3-azidopropyl)-2-(3,4-dihydroxyphenyl)acetamide with C60. Synthesis of CAC60 was confirmed by Fourier-transform infrared, Raman and X-ray photoelectron spectroscopies, and Thermogravimetric analysis. The photocatalytic activity of CAC60 was evaluated by measuring photodegradation of a pharmaceutical compound, cimetidine. CAC60 exhibited the instantaneous adsorption of cimetidine, followed by effective photooxidation under visible as well as ultraviolet irradiations. From the comparison of photodegradation behaviors of unmodified control C60, amine functionalized aziridinofullerenes, and CAC60, we concluded that the aziridine and catechol moieties were responsible for the visible light activity and hydrophilicity of CAC60, respectively.
    Materials Letters 09/2013; 106:213–217. DOI:10.1016/j.matlet.2013.05.025 · 2.49 Impact Factor
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    ABSTRACT: WO3-mediated photocatalytic oxidation is achievable in the presence of electron acceptors as an alternative to O2 or co-catalysts enabling O2 reduction pathway. This study suggests the combination with Fenton-like reagent (Fe(III)/H2O2) as a strategy to improve the photocatalytic activity of WO3. Under neutral pH condition where Fe(III) is present as iron oxide precipitate, photocatalytic degradation of 4-chlorophenol (4-CP) proceeded 3-fold faster in the WO3/Fe(III)/H2O2 system relative to the WO3/H2O2 system, while no noticeable oxidation occurred in the systems of Fe(III)/H2O2, WO3, and WO3/Fe(III). Such efficacy increase at circumneutral pH was observed in photocatalytic oxidation of diverse organics including phenol, bisphenol A, acetaminophen, and carbamazepine. Compatible with the pH dependence of photocatalytic activity of the WO3/Fe(III)/H2O2 system, hydroxylation of benzoic acid and coumarin as indirect indication for OH radical production was drastically retarded with increasing pH. The pH effect indicates that OH radical as primary oxidant may be responsible for the kinetic enhancement in the WO3/Fe(III)/H2O2 system. In that platinum deposits or Nafion layers as physical barriers possibly inhibit surface Fe(III) precipitation, use of platinized or Nafion-coated WO3 caused the negligible photocatalytic improvement in the ternary system. Effective oxidative degradation in the presence of the UV cut-off filter corroborated visible light activation of the WO3/Fe(III)/H2O2 system.
    Applied Catalysis B Environmental 07/2013; s 138–139:311–317. DOI:10.1016/j.apcatb.2013.03.006 · 7.44 Impact Factor
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    ABSTRACT: A photocatalytically active stainless steel filter (P-SSF) was prepared by integrating electrospun TiO2 nanofibers on SSF surface through a hot-press process where a poly(vinylidene fluoride) (PVDF) nanofibers interlayer acted as a binder. By quantifying the photocatalytic oxidation of cimetidine under ultraviolet radiation and assessing the stability of TiO2 nanofibers integrated on the P-SSF against sonication, the optimum thickness of the TiO2 and PVDF layer was found to be 29 and 42μm, respectively. At 10L/m(2)h flux, 40-90% of cimetidine was oxidized when the thickness of TiO2 layer increased from 10 to 29μm; however, no further increase of cimetidine oxidation was observed as its thickness increased to 84μm, maybe due to limited light penetration. At flux conditions of 10, 20, and 50L/m(2)h, the oxidation efficiencies for cimetidine were found to be 89, 64, and 47%, respectively. This was attributed to reduced contact time of cimetidine within the TiO2 layer. Further, the degradation efficacy of cimetidine was stably maintained for 72h at a flux of 10L/m(2)h and a trans-filter pressure of 0.1-0.2kPa. Overall, our results showed that it can potentially be employed in the treatment of effluents containing organic micropollutants.
    Journal of hazardous materials 05/2013; 258-259C:124-132. DOI:10.1016/j.jhazmat.2013.04.047 · 4.53 Impact Factor
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    ABSTRACT: Using the 2010 Deepwater Horizon oil spill in the Gulf of Mexico as an impetus, we explored the potential for TiO(2)-mediated photocatalytic reactive oxygen species (ROS) generation to increase the bioavailability (solubility) and biodegradability of weathered oil after a spill. Food grade TiO(2), which is FDA approved for use as food additive in the United States, was tested as a photocatalyst for this novel application. Photocatalytic pre-treatment (0.05wt.% TiO(2), UV irradiation 18Wm(-2), 350-400nm) for 24h in a bench top photoreactor increased the soluble organic carbon content of weathered oil by 60%, and enhanced its subsequent biodegradation (measured as O(2) consumption in a respirometer) by 37%. Photocatalytic pre-treatment was also tested outdoors under sunlight illumination, but no significant increase in solubility or biodegradation was observed after 11d of exposure. Although sunlight irradiation of food-grade TiO(2) generated ROS (assessed by the degradation of 4-chlorophenol as a probe compound), the efficacy of weathered oil pre-treatment was apparently hindered by sinking of the photocatalysts under quiescent conditions and illumination occlusion by the oil. Overall, results indicate that photocatalytic pre-treatment to stimulate bioremediation of weathered oil deserves further consideration, but controlling the buoyancy and surface hydrophobicity of the photocatalysts will be important for future efforts to enable ROS generation in proximity to the target compounds.
    Chemosphere 11/2012; 90(8). DOI:10.1016/j.chemosphere.2012.10.009 · 3.34 Impact Factor
  • Samuel D Snow · Jaesang Lee · Jae-Hong Kim ·
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    ABSTRACT: The vast range of C60 derivatives makes it difficult to assess potential environmental impact of this class of materials, while past environmental studies mostly focused only on pristine C60. Central to derivatized C60's potential to negatively impact (micro)biological receptors upon unintended release is its unique property of mediating the transfer of light energy to ambient oxygen, producing 1O2. To initiate the process of establishing a thorough understanding of the photo-induced adverse biological effects of functionalized fullerenes and their aqueous dispersions, the photochemical properties relevant to 1O2 production were evaluated using three selected series of mono-, bis- and tris- adducted fullerene materials. Differential 1O2 production of derivatives in toluene were explained by spectral variations under visible and UVA light conditions. Of the nine functionalities studied only aggregates of two positively charged derivatives showed significant photoactivity under experimental conditions. Laser flash photolysis revealed a triplet excited state in the photoactive aggregates with a sufficiently long lifetime to be quenched by 3O2. Dynamic light scattering, transmission electron microscopy and electron diffraction patterns revealed aggregates with sizes typical of aqueous C60 colloids that varied in crystallinity based on functionality. Results raised questions about our current understanding of the photoactivity of fullerene aggregates.
    Environmental Science & Technology 11/2012; 46(24). DOI:10.1021/es303237v · 5.33 Impact Factor
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    ABSTRACT: A magnetite-loaded mesocellular carbonaceous material, Fe(3)O(4)/MSU-F-C, exhibited superior activity as both a Fenton catalyst and an adsorbent for removal of phenol and arsenic, and strong magnetic property rendering it separable by simply applying magnetic field. In the presence of hydrogen peroxide, the catalytic process by Fe(3)O(4)/MSU-F-C completely oxidized phenol and As(III) under the conditions where commercial iron oxides showed negligible effects. Notably, the decomposition of H(2)O(2) by Fe(3)O(4)/MSU-F-C was not faster than those by commercial iron oxides, indicating that hydroxyl radical produced via the catalytic process by Fe(3)O(4)/MSU-F-C was used more efficiently for the oxidation of target contaminants compared to the other iron oxides. The homogeneous Fenton reaction by the dissolved iron species eluted from Fe(3)O(4)/MSU-F-C was insignificant. At relatively high doses of Fe(3)O(4)/MSU-F-C, total concentration of arsenic decreased to a significant extent due to the adsorption of arsenic on the catalyst surface. The removal of arsenic by adsorption was found to proceed via preoxidation of As(III) into As(V) and the subsequent adsorption of As(V) onto the catalyst.
    Chemosphere 08/2012; 89(10):1230-7. DOI:10.1016/j.chemosphere.2012.07.046 · 3.34 Impact Factor
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    ABSTRACT: This study evaluates the potential application of tin porphyrin- and C(60) aminofullerene-derivatized silica (SnP/silica and aminoC(60)/silica) as (1)O(2) generating systems for photochemical degradation of organic pollutants. Photosensitized (1)O(2) production with SnP/silica, which was faster than with aminoC(60)/silica, effectively oxidized a variety of pharmaceuticals. Significant degradation of pharmaceuticals in the presence of the 400-nm UV cutoff filter corroborated visible light activation of both photosensitizers. Whereas the efficacy of aminoC(60)/silica for (1)O(2) production drastically decreased under irradiation with λ > 550 nm, Q-band absorption caused negligible loss of the photosensitizing activity of SnP/silica in the long wavelength region. Faster destruction of phenolates by SnP/silica and aminoC(60)/silica under alkaline pH conditions further implicated (1)O(2) involvement in the oxidative degradation. Direct charge transfer mediated by SnP, which was inferred from nanosecond laser flash photolysis, induced significant degradation of neutral phenols under high power light irradiation. Self-sensitized destruction caused gradual activity loss of SnP/silica in reuse tests unlike aminoC(60)/silica. The kinetic comparison of SnP/silica and TiO(2) photocatalyst in real wastewater effluents showed that photosensitized singlet oxygenation of pharmaceuticals was still efficiently achieved in the presence of background organic matters, while significant interference was observed for photocatalyzed oxidation involving non-selective OH radical.
    Environmental Science & Technology 08/2012; 46(17):9606-13. DOI:10.1021/es301775k · 5.33 Impact Factor

Publication Stats

1k Citations
229.07 Total Impact Points


  • 2014-2015
    • Korea University
      • Department of Civil, Environmental and Architectural Engineering
      Sŏul, Seoul, South Korea
  • 2011-2014
    • Korea Institute of Science and Technology
      • Center for Water Resource Cycle Research
      Sŏul, Seoul, South Korea
  • 2009-2010
    • Rice University
      • Department of Civil and Environmental Engineering
      Houston, Texas, United States
  • 2008-2010
    • Georgia Institute of Technology
      Atlanta, Georgia, United States
  • 2004-2008
    • Pohang University of Science and Technology
      • • School of Environmental Science and Engineering
      • • Department of Chemistry
      Antō, North Gyeongsang, South Korea