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( Yeoung Sang Yun ),( Jong Moon Park ) 한국화학공학회 1997 Korean Journal of Chemical Engineering Vol.14 No.4
A gas recycling photobioreactor was developed to achieve high CO₂conversion, in which Chlorella vulgaris was cultivated under various light intensities. The light intensity affected the algal growth and the CO₂ concentration in the exit gas. However, the final cell density was independent of light intensity and was limited by nitrate concentration in the medium. In the linear growth phase, the CO₂ concentration in the exit gas ranged 4.6 to 6.0 % (v/v) when 20 % (v/v) CO₂balanced with 80 % (v/v) N₂was introduced into the photobioreactor. The gas recycling photobioreactor developed in this work was claimed to be a useful system for microalgal CO₂fixation.
Yun, Ji-In,Bhattarai, Saurabha,Yun, Yeoung-Sang,Lee, Youn-Sik Elsevier 2018 Journal of hazardous materials Vol.344 No.-
<P><B>Abstract</B></P> <P>Although a thiourea-immobilized polystyrene sorbent has been reported to exhibit high Ag<SUP>+</SUP> sorption capacity (135mg/g), it is not stable under the acidic conditions commonly employed for desorption. In this research, we synthesized novel thiourea-immobilized polystyrene (TA-PS) nanoparticles to be highly acid resistant via a two-step procedure from polystyrene nanoparticles: acetylation and the subsequent immobilization of thiourea. We investigated the influences of pH, contact time, and initial concentration of AgNO<SUB>3</SUB> solution on the Ag<SUP>+</SUP> sorption of the polymer nanoparticles and estimated the maximum Ag<SUP>+</SUP> sorption capacity to be 190±5mg/g at a pH of 6. The sorption performance did not significantly decrease in tap water containing competing ions. The sorption kinetic data were well fitted to the pseudo-second-order kinetic model. Overall, the TA-PS nanoparticles exhibited a high Ag<SUP>+</SUP> sorption capacity and high selectivity against alkaline and alkaline earth-metal ions. In particular, their high acid resistance allows them to be used for long time periods in sorption–desorption processes.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Thiourea-immobilized polystyrene (TA-PS) nanoparticles were synthesized. </LI> <LI> TA-PS is highly acid resistant. </LI> <LI> The maximum Ag<SUP>+</SUP> sorption capacity of TA-PS was estimated to be 190±5mg/g. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P> <P>FE-SEM images of TA-PS nanoparticles: (a) before and (b) after sorption of silver ions.</P>
Sung Il Yoon,Minhee Han,Wei Wei,Haribandhu Chaudhuri,Yeoung-Sang Yun 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.126 No.-
Sustainable cost-effective activated charcoal-carboxymethyl cellulose (AC-CMC) fiber was developedthrough a benign method for high-rate water-softening applications. The as-developed fiber was characterizedusing FTIR, BET, stereomicroscope, XRD, and FESEM. The fiber was not only used for the removalof hardness (adsorptions of Ca(II) and Mg(II)) from different aqueous media but also successfully appliedin a membrane system. The effect of pH, contact time, isotherm, and kinetic experiments were conductedto examine the sorption efficiency of the fiber. The fiber showed an adsorption efficacy of 46.1 mg/g andfast rate kinetics of 0.1521 L/min for Ca(II). The results were compared to that of the commercial ionexchangefibers and beads namely Fiban K-1 and 001X8 NA, respectively. The experimental results fittedthe best with the Langmuir isotherm and pseudo-first-order kinetic models. It can be assumed that theelectrostatic and dipole-ion interactions between the fibers and Ca(II)/Mg(II) played a vital role duringthe sorption process. The fiber also showed proficient reusability performance. The developed fiberwas applied in the membrane system and it showed high breakthrough bed volume within a short residencetime of 25.7 seconds. So, this work demonstrates the significant potential of the AC-CMC fiber forhigh-rate water-softening application in the membrane system.