• 한국습지학회지
• /
• 제12권1호
• /
• pp.23-31
• /
• 2010

본 연구는 고농도의 PCE 및 1,1,1-TCA가 단독 또는 혼합물로 오염된 지하수 복원을 위해 영가 금속을 이용한 탈염소환원공정을 적용할 때 기술적으로, 경제적으로 가장 적절한 영가금속 선정을 목표로 수행되었다. 고순도 영가철, 고순도 영가아연, 철광석, 고로 슬래그, 차수재용슬래그, 망간 광석 및 아연 광석 등을 대상으로 회분식 반응조 실험을 수행하였으며, PCE, 1,1,1-TCA 및 혼합물의 분해능 및 탈염소화율을 도출하고, 금속 단가 당 변환량을 포함한 경제성 등을 검토하여 최적의 금속광물을 선정하고자 하였다. 연구결과 단일물질 처리시 고순도 영가철과 고순도 영가아연에 의한 제거율 및 분해능이 가장 높게 나타났으며, 그 다음으로 아연광석에 의한 분해능이 양호하였다. 두 물질 제거를 위한 경제성 비교에서는 고순도 영가철과 고순도 영가아연에 비해 아연광석이 매우 양호한 것으로 나타났다. 두 물질의 혼합처리 시에는 단일 처리에 비해 분해능이 감소하는 것으로 나타났다. 이상의 결과로부터 단일 또는 혼합 1,1,1-TCA, PCE 처리를 위한 분해능, 처리특성 및 경제성 등을 고려하였을 때 아연광석이 가장 적절한 금속광물로 사료된다.

• 환경위생공학
• /
• 제15권1호
• /
• pp.54-61
• /
• 2000

We studied the adsorption characteristics on the treatment process of heavy metal wastewater by using cuttle fish bones powder. When adding the 0.25% cuttle fish born powder in the heavy metal solution, $Fe^{3+}$ and $Pb^{2+}$ were high removed than other heavy metals as above 95%. In the solution which was adjusted to pH 5, 7 and 9, there was not observed the difference thing on the heavy metal removal rate. At test using plating wastewater treatment, adding 1%, 1.5% and 2% of the cuttle fish born powder, the heavy metal removal rate were as follows; Zn 12.5 - 37.5%, Mn 18.0 - 62.2%, Cd 36.8 -93.0%, Cu 51.4 - 97.4%, Cr 70.8 - 99.1%, Fe 87.2 - 99.3% and Pb 92.8 - 99.9%. When adding the 0.15% cuttle fish born powder and mixing for 20 minutes, the solution was happened the adsorption equability. Applied this results to the Freundlich＇s iso-thermal equation, we found the cuttle fish born＇s probability as a good adsorbent.

• 한국물환경학회지
• /
• 제28권2호
• /
• pp.277-284
• /
• 2012

This study developed a new ceramics in which natural zeolite was mixed and calcined with industrial by-product such as converter slag, red mud, and fly ash and evaluated the feasibility of the ceramics for removal of heavy metals in acid wastewater. The removal rate of heavy metal by ceramics increased in the order of ZS (zeolite and slag) > ZR (zeolite and red mud) > ZF (zeolite and fly ash) ceramics. The alkalinity increment and coherence of ceramics were increased in the order of ZS > ZR > ZF ceramics. The mixing ratio of natural zeolite to industrial by-product for maximum removal efficiency of heavy metal was 1:1 for ZS ceramics and 1:3 for ZR and ZF ceramics. The order of removal efficiency of heavy metal was observed to be ZS > ZR > ZF ceramics under the mixing ratio of 1:1 for ZS ceramics and 1:3 for ZR and ZF ceramics. The removal efficiency of heavy metal by ZS ceramics with 1:1 mixing ratio was Al 100%, Cd 54.6%, Cr 99.9%, Cu 98.7%, Fe 99.9%, Mn 42.2%, Ni 59.9%, Pb 99.8%, Zn 87.6%, respectively. In addition, the removal capacity of heavy metal by ZS ceramics was observed to be Al 2.01 mM/g, Cd 0.27 mM/g, Cr 1.02 mM/g, Cu 0.83 mM/g, Fe 0.95 mM/g, Mn 0.41 mM/g, Ni 0.55 mM/g, Pb 0.25 mM/g, Zn 0.70 mM/g, respectively. The comparative evaluation in the light of removal capacity, alkalinity increment, and coherence of ceramics showed the ZS ceramics had higher feasibility as a media than others for removal of heavy metals in acid wastewater.

• Elastomers and Composites
• /
• 제30권3호
• /
• pp.229-234
• /
• 1995

Membrane process has been applied widely to petroleum chemistry, fine chemistry, polymer, electronics, food, bioprocessing, and wastewater treatment process. Membrane process has advantage that there's no phase change through separation, energy consumption is smaller than other separation processes. And equipment investment and operation cost are inxpensive too. We prepared the silicone rubber membrane and then separated the heavy metal ion from wastewater. Silicone rubber membrane was prepared using a superitical fluid process and heavy metal ions were separated from the chromium nitrate, ferric sulfate, cupric sulfate, nickel sulfate aqueous solution. The pressure difference between top and bottom of separation apparatus was preserved by vacuum pump, and the removal amount of heavy metal at each separation step were analyzed by instrumental analysis, AAS. The surface and pore of silicone rubber membrane was investigated using SEM, and the capability of wastewater treatment using a silicone rubber membrane was proposed as calculated removal rate of heavy metal after comparing removal amount of heavy metal to amount of heavy metal in mother solution by AAS analysis.

• 한국환경과학회지
• /
• 제7권5호
• /
• pp.697-705
• /
• 1998

$Pb^{2+}$ removal capacity and initial $Pb^{2+}$ removal rate were compared between non-biomaterials (granular activated carbon, powdered activated carbon, ion exchange resin, zeolite) and biomaterials (activated sludge, Aureobasidium pullulans, Saccharomyces cerevisiae). The $Pb^{2+}$ removal capacity of biomaterials were greater than that of non-biomaterials, generally. The $Pb^{2+}$ removal capacities of non-biomaterials and biomaterials were shown on the order of ion exchange resin ＞ zeolite ＞ granular activated carbon ＞ powdered activated carbon and A. pullulans ＞ S. cerevisiae ＞ activated sludge, respectively. In the initial $Pb^{2+}$ removal rate, the non-biomaterials showed powdered activated carbon ＞ granular activated carbon ＞ zeolite ＞ ion exchange resin and the biomaterials showed A. pullulans ＞ activated sludge ＞ S. cerevisiae. Comparing the $Pb^{2+}$ removal capacity and initial $Pb^{2+}$ removal rate of activated sludge with those of other non-biomaterials and biomaterials, activated sludge may have an availability on the removal of heavy metal ions by the economical and pratical aspects.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2000년도 춘계학술대회 논문집
• /
• pp.735-738
• /
• 2000

The characteristics of wire electrical discharge machining (WEDM) are governed by many factors such as the power supply type, operating condition and electrode material. This work deals with the effect of wire electrode materials on the machining characteristics such as, metal removal rate, surface characteristics and surface roughness during WEDM A wire's thermal physical properties are melting point, electrical conductivity and vapor pressure. One of the desired qualities of wire is a low melting point and high vapor pressure to help expel the contaminants from the gap. They are determined by the mix of alloying elements (in the case of plain brass and coated wire) or the base core material(i.e. molybdenum). Experiments have been conducted regarding the choice of suitable wire electrode materials and influence of the properties of these materials on the machinability and surface characteristics in WEDM, the experimental results are presented and discussed from their metallurgical aspect. And the coating effect of various alloying elements(Au, Ag, Cu, Zn, Cr, Mn, etc.) to the Cu or 65-35 brass core on them was reviewed also. The removal rate of some coated wires are higher than that of 65-35 brass electrode wire because the wire is difficult to break due to the wire cooling effect of Zn evaporation latent heat and the Zn oxide on the surface is effective in preventing short circuit. The removal rate increases with increasing Zn content from 35, 40 and Zn coated wire

• Journal of Radiation Protection and Research
• /
• 제24권2호
• /
• pp.73-86
• /
• 1999

현재 경수로형 원자력발전소의 일차계통 냉각수 정화를 위해 사용되는 이온교환방법은 제염효과가 우수하고 공정이 단순하며 조작이 간편하기 때문에 광범위하게 활용되고 있으나 비금속성분도 함께 제거하여 수지의 수명이 단축되고 폐이온교환수지가 발생되는 단점이 있다. 본 연구에서는 일차계통 냉각수 정화를 위해 사용되는 이온교환수지의 대체공정으로서 전기투석과 이온교환이 결합된 전기탈이온법의 사용가능성을 조사하기 위해 모의 용액을 이용하여 다양한 실험조건하에서 수행하였다. 실험결과 유입유량이 증가할수록 제거율은 증가하고 전력소모는 감소하였다. 금속성분 제거율에서 제염계수 1000으로 일정한 경향을 나타내었으며 전력소모 면에서는 TDS 3 ppm이하를 기준으로 유입유량이 $2.0{\ell}/min$일 때 $40.3mWh/{\ell}$ 이었다. 유입유속이 동일한 조건에서는 희석실에 채운 이온 교환수지의 함량이 증가할수록 금속성분 제거율과 전력소모에서 효과적인 것으로 평가되었다. 이온 교환수지를 채운 전기탈이온 공정은 이온교환수지 자체에 의한 수리적 저항과 현탁질에 의한 수지의 오염으로 인해 운전이 계속될수록 유량이 감소하게 된다. 이러한 단점을 극복하기 위해 이온교환수지 대신 이온전도성 스페이서를 설치하여 실험한 결과 유입유량 문제는 해결할 수 있었으나 전력소모와 금속성분 제거율 및 전류효율 면에서 비효율적인 것으로 평가되었다. 전기탈이온 공정의 연속운전에서도 금속성분 제거율에서 제염계수가 1000으로 안정적인 수준을 유지하였다.

• 한국안전학회지
• /
• 제5권1호
• /
• pp.31-39
• /
• 1990

In this paper, the influence of the table speed, metal removal rate and grinding fluid on long wheel workpiece contact zone at high effect grinding was investigated by theoretical analyses and measuring the temperature, and discussed by the temperature distribution in grinding surface layer. Main results obtained are as follows, 1) Rega.dless of the table speed, the temperature gap of the workpiece(heat influx) is about 6-8 times as high in dry condition as in wet condition. 2) Good grinding condition can be obtained owing to the effect of grinding fluid without any burning defect under the condition of the metal removal rate(1.0mm$^3$/mm.s) in case of wet grinding. 3) When the depth from the surface layer is about 1.25-1.5mm under the condition of the slow table speed, surface temperature goes up higher as the table speed slows down, because long contact time is laked at the surface layer. 4) In case of the same metal removal rate, the lower the table speed becomes, the higher the surface temperature is, because grinding depth has a far more influence on wheel workpiece contact zone than the table speed.

• KSBB Journal
• /
• 제14권2호
• /
• pp.141-145
• /
• 1999

본 연구에서는 농산물의 부산물로 다량 폐기되고 있는 생물질재료 중 건조 밤껍질과, 포르말린 처리한 밤껍질, 인산화 처리한 밤껍질을 이용하여 pH 변화에 따른 중금속 흡착상태를 실험하였다. $Cd^{2+},\;Fe^{2+},\;Cr^{6+},\;Mn^{2+},\;Cu^{2+},\;Pb^{2+}$중금속 등에 대한 시간의 영향은 $Mn^{2+}$은 5분 경과 후, $Cd^{2+}$와 $Cr^{6+}$-는 10분 경과 후, $Fe^{2+}와 Cu^{2+}$는 20분 경과 후에 약간의 흡착 경향성을 보였고, $Fe_{2+}$는 5분 경과 후 계속 흡착이 증가하는 것을 보였다. $Cd^{2+},\;Fe^{2+},\;Cr^{6+},\;Mn^{2+},\;Cu^{2+},\;Pb^{2+}$중금속 등에 대한 pH의 영향은 $Cr_{6+}$인 경우 pH 2의 범위에서 가장 높은 흡착 결과를 보였으며, 나머지 중금속 이온의 겸우 pH 7.0~9.0에서 높은 흡착 경향성을 보였다. 밤껍질에 의한 중금속 이온의 제거율은 pH 7.0-9.0 에서 $\Fe^{2+},\;Mn^{2+},\;Cu^{2+},\;Pb^{2+}$ 들은 70% 이상을, 포르말린 처리한 밤껍질의 경우 $\Fe^{2+},\;Mn^{2+},\;Cu^{2+},\;Pb^{2+}$들은 50% 이상을, 인산화 처리한 밤껍질의 경우 $Cd^{2+},\;Fe^{2+},\;Mn^{2+},\;Cu^{2+},\;Pb^{2+}$들은 60% 이상을 보인 것으로 보아 밤껍질을 포르말린과 인산화 처리한 경우 중금속 이용이 제거율 향상에는 큰 효과가 나타나지 않음을 알 수 있었다.

• 한국환경과학회지
• /
• 제12권12호
• /
• pp.1303-1308
• /
• 2003

This experiment was carried out to investigate the effects of heavy metals (cadmium, chromium, copper and lead) on the seed germination of Arabidopsis thaliana, and examinated the removal effects of biostone and green tea on the heavy metal toxicity. Cadmium and chromium among the four heavy metals had no effect on the seed germination even in the concentration fifty times higher than in the official standard concentration of pollutant exhaust notified by the Ministry of Environment. However, seeds were not germinated in the concentration of copper ten times higher and in the concentration of lead fifty times higher than the official standard concentration. When seeds were sown in the solutions of lead (15, 20, 25 and 30 mg/L) and copper(15 and 20 mg/L), the seed germination rates were 0％ and less than 10％, respectively. However, when biostone(3 g/30 $m\ell$) was added, the seed germination rate was 100％ in all the concentrations. The germination rate was 100％ in distilled water and copper solution (5 mg/L). However, green tea (0.2 g/30 $m\ell$) was added, the seed germination rate was 0％ in both. The results show that cadmiun and chromium had no effect on the seed germination, but lead and copper decreased the rate of seed germination of Arabidopsis thaliana, Biostone removed heavy metal toxicity, but green tea did not removed heavy metal toxicity during germination.