• 공업화학
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• 제16권5호
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• pp.719-723
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• 2005

Tetraethyl orthosilicate (TEOS) 혹은 1,2-bis(triethyoxysilyl)ethane (BTSE)과 여러 종류의 organosilane들을 공중합하여 유 무기 혼성 메조포러스 물질들을 제조하고, 이들이 공기 중의 휘발성 유기화합물(VOC)들을 흡착 제거하는 능력을, TEOS 만을 사용하여 제조한 친수성 무기 메조포러스물질인 SBA-15와 비교 평가하였다. 유기 구조의 도입에 의한 소수성의 증대는 메조포러스 물질이 VOC를 흡착 제거하는데 긍정적 효과를 줌을 관찰하였다. 특히 BTSE와 phenyl triethoxysilane을 중량비 90:10으로 공중합한 유 무기 혼성 메조포러스 물질의 VOC 제거 능력은 우수하였다. 또, 물속에 분산된 기름 성분을 흡착 제거하는데 유 무기 혼성 메조포러스 물질들을 유용하게 응용할 수 있음도 정성적으로 관찰하였다.

• 한국대기환경학회지
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• 제26권3호
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• pp.330-338
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• 2010

In this study, removal characteristics of nitrogen oxides $(NO_x)$ from road transport by using peat as the packing media for biodegradation have been investigated in the long term. Physicochemical and biological treatment of peatmixed media eliminates any requirement to use chemical substances and also facilitates the biodegradable actions of microorganism. Safe biodegradation of pollutants, no need to apply additional microbes owing to their active growth, and no generation of secondary pollutants were found in this experiment. It was concluded that average removal efficiencies of nitric oxide (NO) and nitrogen dioxide $(NO_2)$ were 80% and 97% respectively with respect to the linear velocity 35~40 mm/s and 0.3 ppm ozone concentration in the long period operation. Inflow concentration of nitric oxide over 0.05 ppm was suitable when pretreated with ozone. Non-ozone stage was performed with linear velocity 20~100 mm/s and then the average removal efficiency of nitric oxide and nitrogen dioxide were 38% and 94% respectively. Other results showed that the apparent static pressure was raised with increases in applied water content and aerial velocity in mixed media during fan operation.

• 한국대기환경학회지
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• 제21권5호
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• pp.507-513
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• 2005

Increasing amounts of anthropogenic $CO_2$ emitted to the atmosphere are believed to be a significant factor in global climate change. Hence, the method of chemical absorption has been suggested to separate and recover acid gases such as $CO_2$. In this study, the characteristics of absorption and regeneration of $CO_2$ for the absorbent which adding HMDA (hexamethylenediamine) into AMP (2-amino-2-methyl-1-propanol), hindered amine, was investigated in lab-scale absorption/regeneration reactor. As a result of this study, the removal efficiency of $CO_2$ increased when adding $5.9\%,\;11.7\%\;and\;23.4\%$ HMDA into $30\%$ AMP respectively. Also, the removal efficiency of $CO_2$ increased $6.5\%,\;8.4\%,\;10.3\%$ respectively as compared to AMP alone when the gas flow rate was 7.5 SL/min. In addition, all absorbents used in the study revealed the high stripping efficiency, which was almost $99\%$, at the temperature of $110^{\circ}C$. Thus, the regeneration tower should be operated at $110^{\circ}C$. At this time, the concentration of exhausted $CO_2$ was higher than $99\%$.

• 한국분말재료학회지
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• 제8권2호
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• pp.91-97
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• 2001

The conventional debinding process in metal injection molding is very long time-consuming and unfriendly environmental method. Especially, in such a case of injection molded parts from hard and fine metal powder, such as WC-Co, an extremely long period of time is necessary in the conventional slow binder removal process. On the other hand, supercritical debinding is thought to be the effective method which is appropriate to eliminate the aforementioned inconvenience in the prior art. The supercritical fluid has high diffusivity and density, it can penetrate quickly into the inside of the green metal bodies, and extract the binder. In this paper, super-critical debinding is compared with wicking debinding process. Wax-based binder system is used in this study. The binder removal rate in supercritical $CO_2$ have been measured at $65^{\circ}C$, 75$^{\circ}C$ in the pressure range from 20 MPa to 28 MPa. Pores and cracks in silver bodies after sintering were observed using SEM When the super-critical $CO_2$ debinding was carried out at 75$^{\circ}C$, almost all the wax (about 70 wt% of binder) was removed in 2 hours under 28 MPa and 2.5 hours under 25 MPa.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2003년도 가을 학술논문집
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• pp.158-161
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• 2003

중수로형 원전의 감속재 상층기체에 포함되어 원전 주변 대기로 방출되는 방사성이산화탄소$(^14CO_2)$를 효과적으로 흡착하여 분리, 고정할 수 있는 고효율 흡착제를 개발하기 위해, 활성탄 및 활성탄섬유에 금속수산화물(LiOH)을 담지한 몇 가지의 흡착제를 대상으로 XRD, BET, SEM/EDX 분석을 수행하였으며, 이산화탄소 흡착 성능을 시험하였다. 성능 시험 결과, 활성탄과 LiOH를 물리적으로 혼합한 시료가 함침법으로 LiOH를 활성탄에 담지한 시료에 비해 흡착 성능이 우수함을 알 수 있었으며, 활성탄의 표면을 개질한 결과 1N 질산으로 처리하였을 때에도 흡착성능이 향상됨을 확인하였다.

• 반도체디스플레이기술학회지
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• 제16권1호
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• pp.22-28
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• 2017

The result of stripping process for the removal of the post etch/ash Photoresist (PR) residue on an aluminum patterned wafer by using supercritical $CO_2$ ($sc-CO_2$) mixture, was investigated by scanning of electron microscope (SEM) inspection of wafer, measuring the cloud points and visual observation of the state of $sc-CO_2$ mixtures. It was found that $sc-CO_2$ mixtures were made by mixing additives and $sc-CO_2$ should form homogeneous and transparent phase (HTP) in order to effectively and uniformly remove the post etch/ash PR residue on the aluminum patterned wafer using them. The additives were formulated by mixing and co-solvents like an amine compound and fluorosurfactants used as HTP agents, and the PR residue on the wafer were able to be rapidly and effectively removed using the $sc-CO_2$ mixture of HTP. The five kinds of additives were formulated by the recipe of mixing co-solvents and surfactants, which were able to remove PR residue on the wafer by mixing with $sc-CO_2$ at the stripping temperature range from 40 to $80^{\circ}C$. The five kinds of $sc-CO_2$ mixtures which were named as PR removers were made, which were able to form HTP within the above described stripping temperature. The cloud points of $sc-CO_2$ mixtures were measured to find correlation between them and HTP.

• Nuclear Engineering and Technology
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• 제54권11호
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• pp.4013-4021
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• 2022

A kind of zirconium phosphate mesoporous coordination polymer Zr-EDTMPA was successfully synthesized and characterized using XRD, FTIR, TGA, EA, SEM-EDS, and N₂ sorption-desorption measurements. The prepared Zr-EDTMPA was first employed for the removal of Co(II) from an aqueous solution, and the effects of pH, contact time, temperature, initial Co(II) concentration, reusability, and sorption mechanism were systematically investigated. The results showed that the Zr-EDTMPA is a zirconium phosphate complex formed by the coordination of EDTMPA to Zr in a molar ratio of 1:1. The sorption of Co(II) by Zr-EDTMPA was a pH-dependent, spontaneous and endothermic process, which was better fitted to the pseudo-second-order kinetic model and Langmuir isotherm model. The Zr-EDTMPA was demonstrated to have excellent reusability and presented a high sorption capacity of 73.0 mg·g^-1 for Co(II) at pH 8.0. The sorption mechanism was mainly attributed to the strong coordination between cobalt and the untapped hydroxyl functional groups on Zr-EDTMPA, which was confirmed by XPS spectra. Therefore, as a candidate sorbent with high sorption capacity and excellent reusability, Zr-EDTMPA has a great potential for the removal of Co(II) from aqueous solutions.

• 상하수도학회지
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• 제30권6호
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• pp.683-690
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• 2016

Modified coagulants were investigated for the removal of phosphorus from secondary effluent of wastewater treatment. The modified coagulants were prepared by mixing alkali earth metal ions such as calcium and magnesium. The basicity of a coagulant influenced on the removal of phosphorus, and coagulants with basicity of 5.9% showed a better removal of total phosphorus than that of 38.5%. Also, coagulants with alkali earth metals enhanced the performance of coagulation by 10% and resulted in 67.1% for total phosphorus removal. Moreover, the removal of suspended solids and chemical oxygen demand was improved using coagulants with low basicity and earth metal ions. Results of this study demonstrated that the use of coagulants with low basicity, and calcium and magnesium ions is recommended to improve wastewater effluent quality.

• 한국환경과학회지
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• 제28권8호
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• pp.669-676
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• 2019

The purpose of this study was to evaluate the effects of different Hydraulic Retention Times (HRTs) on the contaminant removal efficiency using Aerobic Granular Sludge (AGS). A laboratory-scale experiment was performed using a sequencing batch reactor, and the Chemical Oxygen Demand (COD), nitrogen, orthophosphate removal efficiency, AGS/MLSS ratio, and precipitability in accordance with the HRT were evaluated. As a result, the COD removal efficiency was not significantly different with the reduction in HRT, and at a HRT of 6 h, the removal rate was slightly increased owing to the increase in organic loading rate. The nitrogen removal efficiency was improved by injection of influent division at a HRT of 6 h. As the HRT decreased, the MLSS and AGS tended to increase, and the sludge volume index finally decreased to 50 mL/g. In addition, the size of the AGS gradually increased to about 1.0 mm. Therefore, the control of HRT provides favorable conditions for the stable formation of AGS, and is expected to improve the contaminant removal efficiency with the selection of a proper operation strategy.

• 공업화학
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• 제16권5호
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• pp.635-640
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• 2005

매개전해산화는 저온과 저압 분위기에서 수용액 중에 존재하는 유기물을 전기화학적으로 산화하는 과정이다. 이 공정은 유해 유기물을 함유한 폐물처리에 사용할 수 있는 좋은 공법중의 하나이다. 이 논문은 Fe(III)/Fe(II)나 Co(III)/Co(II) 산화환원계를 이용하여 질산용액 중에서 에틸렌글리콜의 매개전해 산화에 관한 연구를 하였다. 이 논문에서는 에틸렌글리콜을 매개전해 산화시 전류밀도, 지지전해질 농도, 체류시간, 제거효율 등을 검토하였다. 매개전해산화시 에틸렌글리콜의 제거효율은 Fe(III)/Fe(II) 산화환원계보다 Co(III)/Co(II) 산화환원계가 우수하였고 매개전해산화 제거효율은 100%이었다. 에틸렌글리콜을 시료로 하였을 경우 좋은 수율로 탄산가스가 생성됨을 관찰할 수 있었다.