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( Abinashi Sigdel ),박정원,곽효은,민소진,박병규 한국공업화학회 2015 한국공업화학회 연구논문 초록집 Vol.2015 No.1
Amorphous iron oxide-impregnated alginate beads were developed for the removal of both arsenic(III) and arsenic(V) from water phase. The IO-alg beads were characterized by SEM-EDX. Arsenic adsorption efficiency by the beads was investigated as a function of contact time, concentration, pH, dosage and iron loading in the beads in batch experiments. Arsenic removal increased with increasing dose and initial concentration. Arsenic(III) adsorption by the beads was favored in pH range 6-9, while As(V) adsorption was favored in acidic pH. Pseudo-second-order kinetics and Freundlich isotherm model best described adsorption phenomena in terms of kinetics and equilibrium, respectively. Effectiveness of the beads for arsenic adsorption was not significantly affected even in the presence of common natural anions; only phosphate showed pronounced competitive effect especially at high concentration.
Abinashi Sigdell,박병규,박정원,곽효은 한국공업화학회 2016 Journal of Industrial and Engineering Chemistry Vol.35 No.-
Hydrous iron oxide impregnated alginate beads were developed for effective arsenic removal fromwater. As(III) adsorption was maximized at neutral pH while As(V) adsorption was higher in acidicconditions. Adsorption efficiency for both As(III) and As(V) mostly increased with increasing ironloading, but As(V) adsorption slightly decreased at high iron loading. Phosphate showed a pronouncedinterfering effect, especially at high concentration. Kinetics data fitted to pseudo-second-order and intra-particle diffusion model suggested chemisorption and intra-particle diffusion might mainly governAs(III) and As(V) adsorption, respectively. Beads were regenerated using NaOH solution and successfullyreused for multiple cycles.
Applicability of TOPMODEL in the Catchments of Nepal: Bagmati River Basin
Abinashi Sigdell,전병훈,Raghunath Jha,Dhruba Bhatta,Reda A.I. Abou-Shanab,Veer Raghavulu Sapireddy 한국자원공학회 2011 Geosystem engineering Vol.14 No.4
TOPMODEL was applied to simulate runoff hydrograph in Bagmati River Basin. Digital Elevation Model (DEM), soil, land-use and other spatial data were analyzed using Geographic Information System (GIS). To account for spatial variability of precipitation, climate and land-use, the entire basin was divided into sub-basins and the model was run separately. Other additional computer codes have been developed for computing evapotranspiration and channel routing so as to apply TOPMODEL as a complete hydrological model for medium to large basin. Less sensitive or physically based parameters were directly measured from topographic and soil maps using looked up table, where as more sensitive parameters such as saturated transmissivity [ln(T0)] and exponential decay coefficient (m) to each sub-basin were calibrated by manual iterative method. However, subjective and objective methods were applied to test the goodness of fit of simulated hydrographs to observed hydrographs. The results are satisfactory with Nash efficiency as much as 84.8% in calibration and 82.5% in validation. The results showed annual peak, runoff volume, annual average wet and dry seasons flows simulation using the model were relatively reasonable. Most of the river basins of Nepal are steep to moderately steep sloped, densely vegetated and receives appreciable amount of frequent precipitation and hence TOPMODEL assumptions are valid. The limited available resources used to achieve these results showed that TOPMODEL will be applicable in medium to large spring fed catchments of Nepal.
Immobilization of hydrous iron oxides in porous alginate beads for arsenic removal from water
Sigdel, Abinashi,Lim, Joowan,Park, Jeongwon,Kwak, Hyoeun,Min, Sojin,Kim, Keehong,Lee, Hosung,Nahm, Chang Hyun,Park, Pyung-Kyu The Royal Society of Chemistry 2018 Environmental science Vol.4 No.8
<P>For removal of arsenic in the aqueous phase, hydrous iron oxides (HIOs) were immobilized in alginate beads with enhanced porosity (designated as HIO-P-alginate beads). The HIO-P-alginate beads had macropores, observed by SEM, as well as mesopores and featured a higher BET surface area than previously developed adsorbent beads. Thus, the adsorption of As(iii) and As(v) by the HIO-P-alginate beads was more rapid than that of previously reported HIO-alginate adsorbents. The kinetics of adsorption were well described by a pseudo-second-order model, indicating that chemisorption mainly governed the As(iii) and As(v) adsorption. We confirmed a chemisorption mechanism for the As(iii) and As(v) adsorption, through isotherm studies using the Dubinin-Radushkevich isotherm model. The application of an intraparticle diffusion model to the kinetic data suggested that the As(v) adsorption onto the HIO-P-alginate beads was controlled entirely by intraparticle diffusion whereas the As(iii) adsorption was governed by intraparticle diffusion only at short contact times. As(iii) adsorption was highest at neutral pH; however, As(v) adsorption was highest at low pH. Both As(iii) and As(v) adsorption did not compete with nitrate adsorption, and the As adsorption improved with increasing ionic strength. The HIO-P-alginate beads could be regenerated several times with a NaOH solution and were successfully reused for arsenic removal.</P>
아비나시시델 ( Abinashi Sigdel ),구자건 ( Ja Kon Koo ) 한국환경영향평가학회 2012 환경영향평가 Vol.21 No.6
네팔 지방자치단체의 고형폐기물 관리 부서는 도시계획 및 개발국이나 환경위생 부서 또는 일반 복지 부서에서 담당한다. 네팔에는 폐기물관련법과 기준, 지침이 제정되어 있으며 지방자치단체법에 의해 지방자치단체 여건에 맞게 관련 법률 조항을 개정할 수 있다. 네팔에서 발생하는 가정폐기물의 65%는 유기성 폐기물이나, 폐기물 관리는 아직 체계화되지 않고 있다. 지방 NGOs와 일부 부락이 분리수거와 퇴비화를 실시하고 있으나 병원폐기물과 같은 유해폐기물의 경우 병원이 자체적으로 소각하고 있으며 지방자치단체의 의해 적절히 처리되지 않고 있다. 현재 네팔에서는 폐기물이 비위생 매립 방식에 의해 처리되고 있어서 지방자치단체에서 이를 금지하고 위생매립지를 확대 설치할 계획이다. 그럼에도 불구하고 기술 및 전문인력, 예산의 부족, 민간자본 및 시민들의 참여 부족으로 인해 지방자치단체가 설정한 폐기물관리 목표를 달성하지 못하고 있는 실정이다. 네팔 지방자치 단체들이 당면한 시급한 과제는 지속가능한 폐기물관리 계획 및 전략의 수립이다. 네팔 지방자치단체의 폐기물관리 계획은 폐기물의 적정 처리를 위한 제도적 측면의 강화는 물론, 폐기물 분리 배출 및 수거에 시민들의 동참을 이끌어내고 이해관계자의 참여 확대, 폐기물 처리 비용, 폐기물 처리를 위한 적정기술의 개발과 같은 내용을 포괄할 수 있어야 한다.
조동완,전병훈,정우식,Abinashi Sigdell,권오훈,이상훈,Akhil N. Kabra 한국자원공학회 2013 Geosystem engineering Vol.16 No.3
A composite adsorbent was prepared by immobilizing nanosized graphite carbon, obtained from an electrochemical process, in calcium alginate beads to remove Pb(II) and Ni(II) from aqueous solution. Potential of the adsorbent was evaluated by comparing adsorption kinetics and capacity of the nanosized graphite carbon-impregnated calcium alginate beads (NGCAB) with those of the pure calcium alginate beads (AB) in batch experimental reactors. Kinetic studies indicated that both ions onto AB and NGCAB reached adsorption equilibria at 16 and 12 h, respectively, and the experimental kinetic data were well described by a pseudo-second-order regression model. Relatively rapid uptake of both ions occurred within the first 2 h, followed by slower sorption process which was well explained by the intraparticle diffusion model of Weber and Morris. The maximum equilibrium uptake of Pb(II) and Ni(II) by NGCAB with the initial concentration range of 903 and 1023 mg/L were approximately 460.9 and 93.3 mg/g, respectively. Adsorption isotherm of Pb(II) onto AB was well fitted by Langmuir isotherm model, while that of NGCAB showed a good prediction using the Freundlich isotherm model. The Freundlich isotherm model was more suitable to describe Ni(II) adsorption by both adsorbents. The overall results demonstrated a potential applicability of NGCAB for Pb(II) and Ni(II) removal from aqueous solutions.