► Calcium ions could form amorphous calcium carbonate in alkaline condition. ► Arsenic would be removed by the amorphous calcium carbonate. ► Arsenic adsorbed onto the slag would not be easily ...desorbed to aqueous state.
This study focused on the environmental risk of steel making slag itself, arsenic removal mechanism and re-leaching possibility of arsenic to aqueous state after the adsorption. The purpose of the study is to promote the use of steel making slag as a low-cost adsorbent for arsenic in aqueous system. Calcium was easily dissolved out from the slag and become the dominant substance in the leachate. Some of the calcium could form amorphous calcium carbonate in alkaline condition, and arsenic in the aqueous solution would be removed by being co-precipitated with or adsorbed onto the amorphous calcium carbonate. Most of the amorphous calcium carbonate containing arsenic would be bound to amorphous iron oxide of the slag. When the slag was used as an adsorbent for arsenic removal, a little amount of toxic chemicals were leached from the slag itself under pH 0.8 to 13.6. Also, 70–80% of arsenic laden on the slag was bound to amorphous iron oxide which would not easily desorb unless given a reducing and complexing condition. Showing 95–100% removal efficiency near initial pH 2, the slag, therefore, could be used as an appropriate adsorbent for eliminating arsenic in acidic aqueous solution.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The effective site assessment is crucial to the successful remediation of the subsurface contaminated with light nonaqueous phase liquids (LNAPLs). Recent studies showed that large spatial volumes of ...the subsurface contaminated with LNAPLs could be investigated with the partitioning tracer method. This study investigated the applicability of the partitioning tracer method for detecting and quantifying refined petroleum products in a saturated aquifer containing alluvial soil or weathered granite soil. In the batch-partitioning experiments, the partition coefficients of alcohol tracers between the petroleum mixture and water were measured, and they were found to be increased in proportion to the boiling points of the alcohol tracers when the molecular weights of the alcohol tracers were similar. The sorption isotherm experiments indicated that a considerable amount of 4-methyl-2-pentanol was sorbed into Jumunjin sand (JS) or weathered granite soil (WGS). In the column experiments, it was confirmed that the partitioning tracer method could be used as a method for detecting the presence of the petroleum mixture in saturated soil, and the residual saturation of the petroleum mixture in the soil column prepared by firstly contaminating with the petroleum mixture and secondly saturating with water was measured higher than that in the soil column prepared by firstly saturating and secondly contaminating. The highest accuracy of estimation using the partitioning tracer method was found for 2-ethyl-1-butanol and the lowest accuracy was found for 4-methyl-2-pentanol.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Partitioning tracer method has been studied as an effective technique for estimating the light nonaqueous-phase liquid (LNAPL) contamination in the subsurface. This study is for investigating the ...effect of soil organic contents on the LNAPL quantification using partitioning tracer method. The sorption characteristics of alcohol tracers to the soils having different organic carbon contents were evaluated by sorption isotherm experiments. In the column tests, the soils were contaminated with jet-fuel and the average saturations of residual jet-fuel were estimated by partitioning tracer method and compared with that by the volume measurement. The sorption results indicated that considerable amount of 4-methyl-2-pentanol and hexanol could be sorbed to the soils and the sorption amount of 2-ethyl-1-butanol was relatively smaller than those of the other alcohol tracers. The column experiments demonstrated that the accuracy of quantification for the jet-fuel by partitioning tracer method should decrease with increasing the soil organic carbon contents. However, the accuracy could be enhanced by considering the sorption of tracer to the soils, especially for the tracer of 2-ethyl-1-butanol.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The aim of this work is to estimate biogas production by anaerobic digestion of agricultural byproduct silage at the low carbon green village in South Korea. The composition of agricultural byproduct ...from hot pepper farms was analyzed and it was found to be favorable with anaerobic digestion. In the cases of silage materials, the theoretical methane potentials of all of the ensiled materials were increased with silage storage having an increased range from 103 to 120 % compared to that without ensiling. The biochemical methane potential (BMP) tests showed that the ultimate methane potential of ensiled material was measured to be higher than that of raw material without silage storage, while the first order hydrolysis constant was lower. All of the silage materials containing microbial additives used in this study showed higher ultimate methane potentials and first order hydrolysis constants than raw material and silage material without additives. The change of ultimate methane potential was analyzed over time, and all of the test materials, except Day 2, showed higher ultimate methane potential than raw material, Day 0, and the highest was found on Day 40.
Previous studies have revealed that the application of zero-valent iron (ZVI) in reducing nitrate is limited by ammonium production and the requirement for adequate pH control. The current study ...focused on developing a new material potentially applicable in permeable reactive barriers, which can reduce nitrate without ammonium release under unbuffered pH. The new material, referred to as ZanF, is derived from zeolite modified by Fe(II), followed by borohydride reduction. The pseudo-first-order rate constant
(
kobs
)
of ZanF in the early period of nitrate reduction was 10 times higher than that of the ZVI used in this study. However, the
kobs
of ZanF decreased in the reaction period that followed. Even though both ZVI and ZanF produced ammonium as a product of nitrate reduction, ZanF removed it to below detection limits via adsorption, whereas ZVI did not remove it to any significant extent. ZanF maintained its high reactivity even under an initial pH of 6.2 without buffer. The higher ZanF/solution ratio increased the removal rate of ZanF as well as the removal efficiency.
Full text
Available for:
DOBA, FGGLJ, IZUM, KILJ, NUK, ODKLJ, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
시설농업부산물의 잠재메탄발생량 평가 및 사일로 저장에 따른 메탄 발생 변화 이유진(Yu Jin Lee); 조한상(Han Sang Cho); 김재영(Jae Young Kim) ...
Daehan hwan'gyeong gonghag hoeji,
2012, Volume:
34, Issue:
11
Journal Article
Peer reviewed
Open access
In this study, the biochemical methane potentials of different agricultural residues produced from agricultural plastic greenhouse were determined. Additionally, ensiling storage practice was applied ...on agricultural residues for its effect on biogas production. Agricultural residues of cabbage, strawberry, tomato, cucumber, and oriental melon were selected as sample. The methane potential and biodegradability of agricultural residues ranged from 149~286 mL-$CH_4/g$-VS, 27~48% (by vol.), respectively and methane production was in order of cabbage > oriental melon > strawberry ${\approx}$ cucumber > tomato. Ensiling caused difference in methane production in a range of -11~36% (by vol.) per VS compared with raw material. An increase in methane potential was presumably linked to the organic acid accumulation, cellulose degradation and decrease in methane potential was due to chemical composition change, ammonia accumulation during the storage process. 본 연구에서는 BMP (Biochemical Methane Potential) test를 통해 얼갈이배추, 딸기, 토마토, 오이, 참외 시설농업부산물의 잠재메탄발생량을 조사하였다. 또한, 시설농업부산물을 사일로에 저장하고 저장 전후의 잠재메탄발생량을 비교하여 사일리지 저장기술이 메탄 생산에 미치는 영향을 분석하였다. 대상 시료의 잠재메탄발생량과 생분해도는 각각 149~286 mL-$CH_4/g$-VS, 27~48%(by vol.)의 범위를 나타내었으며 메탄발생량은 얼갈이배추 > 참외 > 딸기 ${\approx}$ 오이 > 토마토 순으로 조사되었다. 사일로 저장 후, 원시료와 비교하였을 때 VS 기준 메탄발생량이 -11~36%(by vol.) 증감하여 시료 별로 상이한 결과를 보였다. 저장기간 중 유기산 증가, 섬유소 분해로 메탄발생량이 증가하고 화학 성분의 변화, 암모니아 저해로 메탄발생량이 감소한 것으로 판단된다.
The effects of a propulsor on the hydrodynamic forces acting on an autonomous underwater vehicle (AUV) were investigated by towing tank model tests. A mathematical maneuvering model using a whole ...vehicle model was established, and captive model tests using vertical planar motion mechanism equipment were performed to obtain maneuvering coefficients. The Reynolds number of the full scale test model in the operation condition was 4.12 × 106, and the revolution rate of the propulsor was fixed at the self-propulsion point. The forces on the body and control fins were measured in static drift, control fin deflection, pure heave and pure pitch tests with and without the propulsor. The propulsor effects on the hydrodynamic force and moment were identified as spatially irregular thrust, flow acceleration around the control fins, and added mass of the propulsor. In the simulation using the component model where the propulsor effect considered as a constant thrust, the maneuverability of the AUV was overestimated compared to that of the whole vehicle model. Thus, the mathematical maneuvering model should consider propulsor-hull interactions.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
PDF
