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Do, Quoc Cuong,Kim, Do-Gun,Ko, Seok-Oh Elsevier 2018 JOURNAL OF CLEANER PRODUCTION Vol.172 No.-
<P><B>Abstract</B></P> <P>The occurrence of pharmaceuticals in the environment has received wide attention, and they have recently been considered as emerging organic contaminants. Since conventional wastewater processes are not particularly effective, the development of new technology that can completely remove pharmaceutical compounds in aquatic environments is an urgent need. Recently, iron-copper bimetallic catalysts have attracted increasing attention, and they are known as good Fenton reagents for the degradation of persistent organic pollutants. In this study, yolk-shell structured Fe<SUB>3</SUB>O<SUB>4</SUB>@SiO<SUB>2</SUB> was prepared via a spontaneous self-transformation process, and it was decorated with copper nanoparticles (Fe<SUB>3</SUB>O<SUB>4</SUB>@SiO<SUB>2</SUB>@Cu) to produce a novel catalyst aimed at the rapid catalytic oxidation of acetaminophen in the heterogeneous Fenton reaction. Different ratios of Fe<SUB>3</SUB>O<SUB>4</SUB> and copper were obtained by varying the precursor amounts of yolk-shell and copper salt. The catalyst properties were characterized by several techniques to verify the successful synthesis of the targeted materials. The results demonstrated that the Fe<SUB>3</SUB>O<SUB>4</SUB>@SiO<SUB>2</SUB>@Cu was controllably prepared, copper nanoparticles were firmly immobilized on the mesoporous silica shell, and the decoration of copper did not impact the yolk-shell structure of the precursor material. The catalytic activity of Fe<SUB>3</SUB>O<SUB>4</SUB>@SiO<SUB>2</SUB>@Cu was much better than that of Fe<SUB>3</SUB>O<SUB>4</SUB>@SiO<SUB>2</SUB> for the degradation of acetaminophen. The catalytic performance of Fe<SUB>3</SUB>O<SUB>4</SUB>@SiO<SUB>2</SUB>@Cu increased with increasing copper content. Radical scavenging studies showed that •OH is the main reactive species contributing to acetaminophen degradation. In addition, the catalyst also exhibited good separation and satisfactory regeneration properties. The decoration of copper nanoparticles onto the yolk-shell structure Fe<SUB>3</SUB>O<SUB>4</SUB>@SiO<SUB>2</SUB> was proved to be an attractive alternative method to obtain a novel bimetallic catalyst applied in heterogeneous Fenton-like system for the removal of persistent pharmaceuticals from wastewater.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Do, Quoc Cuong,Kim, Do-Gun,Ko, Seok-Oh American Chemical Society 2017 ACS APPLIED MATERIALS & INTERFACES Vol.9 No.34
<P>-like Recently, yolk shell structured materials with active metal cores have received considerable attention in heterogeneous Fenton-like systems, which have excellent catalytic performance. In this study, we initially attempted the nonsacrificial template synthesis of yolk shell structured nanoparticles with magnetite cores encapsulated in a mesoporous silica shell (Fe3O4@SiO2) via a modified sol gel process and then evaluated their catalytic activity for acetaminophen degradation in Fenton-like systems. Second, copper nanoparticles were decorated on the surface of the Fe3O4@SiO2 microspheres (Fe3O4@SiO2@Cu) to enhance the catalytic activity. The morphological, structural, and physicochemiCal properties of the prepared materials were characterized via X-ray diffraction, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, field emission transmission electron microscopy, nitrogen adsorption desorption isotherms, specific surface area, (potential, magnetic properties, and Fourier transform infrared spectroscopy. The results demonstrated a successful fabrication of the targeted materials. The yolk shell structured materials possess a spherical morphology with an active core, protective shell, and hollow void. The Fe3O4@SiO2 and Fe3O4@SiO2@Cu variants showed acetaminophen removal rates significantly higher compared to those of their counterparts, i.e., the Fe3O4 and Fe3O4@Cu core shell structures. Fe3O4@SiO2@Cu showed that the copper nanoparticles were firmly immobilized on the mesoporous silica shell, dramatically improving the catalytic performance. Both the yolk shell structured Fe3O4@SiO2 and Fe3O4@SiO2@Cu exhibited good separation and satisfactory regeneration properties, which could be recycled six times without any obvious decline in catalytic activity. Overall, the results of this study suggested that Fe3O4@SiO2 and Fe3O4@SiO2@Cu yolk shell nanostructures could be promising catalysts for a heterogeneous Fenton-like system by which the removal of emerging contaminants can be greatly improved.</P>
Thermodynamic analysis of fatty acid harvesting by novel carbon-based adsorbent
Do, Quoc Cuong,Kang, Seoktae Springer-Verlag 2016 Environmental Science and Pollution Research Vol.23 No.8
<P>In this study, separation and concentration of fatty acids (FA) from the synthetic food processing wastewater containing low concentration of FA (250 mg/L) were investigated using expanded graphite (EG) as a novel adsorbent at different temperatures (298 similar to 318 K). The adsorption results were further analyzed to verify adsorption mechanisms and thermodynamics of FA onto EG. Results show that the adsorption of FA onto EG was explained well by the Langmuir model with the maximum adsorption capacity up to 8.01 g FA/g EG at 298 K, and considerably affected by temperature. The adsorption kinetics fitted with pseudo-second-order kinetic model and the adsorption mechanism analysis showed that the intraparticle diffusion was not the rate-limiting step, but the coalescence of FA droplets played the significant role for novel adsorption of FA onto EG. The calculated activation energy and thermodynamic parameters such as Gibbs free energy change (Delta G(0)), enthalpy change (Delta H-0), and entropy change (Delta S-0) indicated that the adsorption of FA onto EG was very feasible, was highly spontaneous, occurred physically, was exothermic in nature, and was stable in aquatic environmental changes. Overall, FA can be effectively harvested and concentrated from the food processing wastewater by EG even at low concentration.</P>
Thien An Le,Quoc Cuong Do,김영민,김태완,채호정 한국화학공학회 2021 Korean Journal of Chemical Engineering Vol.38 No.6
The emerging H2 economy faces storage and transport challenges, and the use of ammonia (NH3) as a COx-free source of H2 via NH3 decomposition has recently attracted attention. Noble Ru-based catalysts are considered the best choice for highly efficient NH3 decomposition; however, their high cost and limited availability are disadvantages in large-scale applications. Otherwise, among non-noble metal-based catalysts, Ni-based catalysts are the most active, and Ni is considered a good alternative candidate material for NH3 decomposition because of its low cost. At present, some challenges remain in efforts to improve the efficiency of both Ru- and Ni-based systems. This review covers recent developments regarding these catalysts and can serve as a comprehensive work for evaluating effective long-term strategies.
탁혜련,정영균,김효전,( Quoc Cuong Do ),강석태 한국공업화학회 2020 한국공업화학회 연구논문 초록집 Vol.2020 No.-
A residue of micropollutants in drinking water cause health problmes. However, conventional water treatment couldn’t mineralize it. To enhance the removal efficiency, ozone with ceramic membrane system is proposed. Moreover, the heterogeneous catalysts are introduced in the ozonation processes due to the increased production of hydroxyl radicals. In this study, we conducted the hybrid ozone-ceramic membrane process with V<sub>2</sub>O<sub>5</sub>-TiO<sub>2</sub> for the enhancement of removal of micropollutants. After V<sub>2</sub>O<sub>5</sub> was successfully coated on the membrane through filtration-coating method, the catalytic oxidation effect was evaluated in the presence of ozone. The hybrid system was conducted in the dead-end cell, 2 mg/L of dissolved ozone concentration, and 1 mg/L of 4 selected compounds. As a result, the hybrid system with V<sub>2</sub>O<sub>5</sub>-TiO<sub>2</sub> catalyst depicted higher removal rate than without catalyst due to the catalytic reaction between ozone and V<sub>2</sub>O<sub>5</sub> nanoparticles incorporated in the ceramic membrane.