• 한국환경과학회지
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• 제17권10호
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• pp.1147-1154
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• 2008

Road runoff, one of non-point source pollutants, contains various heavy metals, most of which flow into discharge waters without being treated. The mechanism of removing the heavy metals in water is similar to that of removing micro-particles. Therefore, it is considered that it is possible to remove a lot of the heavy metals contained in the road runoff by filtering or absorbing them. In this paper, performed has been a basic study on the characteristics of UNFS (Up Flow Non-Point Source Filtering System) using carbide pellet and zeolite pellet as double-layer filtering mediums to treat the road runoff. The removal rate with filtering and absorption time has been shown as follows: 29.0% for Cr; 27.8% for Cd; 25.7% for Fe; 25.4% for Co; 21.2% for Pb; ]9.6% for Zn; 18.2% for Al; 17.0% for Mn; 11.3% for Ni; 7.5% for Cu. The overall removal rate according to influx change has been shown to be approximately 30%, and the load of heavy metals flowing out in initial precipitation could be reduced by using carbide as a recycling filtering medium. When the removal as coarse particles settle is added up, it is expected that UNFS will result in a higher removal rate.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2005년도 총회 및 춘계학술발표회
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• pp.363-370
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• 2005

There are approximately 2,000 metallic mines which have been abandoned in Korea. Most of the mines are located in the watershed area, which is main source of drinking water for Seoul Metropolitan area. Untreated mining wastes are remained around abandoned mines in study area. These mining wastes, flowing into farmland and stream in the downstream of abandoned mines, would cause water and soil pollution. The mining waste samples from Guedo mine, Manjung mine and Joil mine recently abandoned were collected for the evaluation of the potential of water pollution by mine waste. Index of geoaccumulation($M\"{u}ller$, 1979), fractional composition and removal efficiency of some heavy metals by different concentration of HCl treatment were analyzed. Index of geoaccumulation of Cd, Pb, Zn, Cu, Ni and Cr are 6, $4{\sim}6,\;0{\sim}6,\;4{\sim}5$, 2 and 0 respectively. Index of geoaccumulation of Cd, Pb, Zn and Cu reveals the mining wastes has high pollution pottential in the area. Organic fraction of Cu, reducible fraction of Pb, residual fraction of Ni and Zn were the most abundant fraction of heavy metals in mining wastes.

• 한국수소및신에너지학회논문집
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• 제9권4호
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• pp.161-167
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• 1998

Ni/MH 2차전지의 음극용 금속간화합물전극의 부식특성에 미치는 합금원소와 결합제의 영향을 조사하였다. 전극의 재료는 $(LM)Ni_{4.49}Co_{0.1}Mn_{0.205}Al_{0.205}$와 $(LM)Ni_{3.6}Co_{0.7}Mn_{0.3}Al_{0.4}$의 $AB_5$ type합금을 모재로 하였다. 여기에 Si sealant 또는 PTFE를 결합제로 첨가한 것과 원재료 분말에 구리를 20% 무전해도금한 것을 냉간 압착하여 전극을 제조하였다. 부식특성을 조사하기위해 탈공기된 6M의 KOH 용액에서 동전위법과 순환전위법을 이용하여 부식전류와 전류밀도를 측정하였다. 모재에 Co가 많이 함유되면 전극의 내식성을 향상시키고 Ni이 많이 함유되면 충전과 방전을 반복하는 동안에 전극의 안정성을 저하시켰다. 부식전류밀도는 Si sealant를 결합제로 사용한 전극의 경우가 PTFE를 사용한 전극의 경우보다 낮았고 Cu가 도금된 전극은 내식성에서 가장 우수하게 나타났다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제19권5호
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• pp.26-34
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• 2014

A $1.5m(L){\times}1.0m(W){\times}1.1m(H)$ polypropylene (PP) field scale electroniketic system coupled with stainless steel electrodes was designed to examined metal removal performance applied 0.2-0.35 V/cm potential gradient and 0.05-0.5M lactic acid for 20 day. Electroosmosis permeabilities of $2.2{\times}10^{-5}cm^2/V-s$ to $4.8{\times}10^{-5}cm^2/V-s$ were observed and it increased with the potential gradient increased. The reservoir pH controlled at $7.0{\pm}1.0$ has been effectively diminished the clogging of most metal oxides. The best removal efficiency of Zn, Pb, and Ni was 78.4%, 84.3%, and 40.1%, respectively, in the field scale EK system applied 0.35 V/cm and 0.05M lactic acid for 20 days. Increasing potential gradient would more effectively enhance metal removal than increasing concentration of processing fluid. The reservoir and soil temperatures were majorly related to potential gradient and power consumptio. A $4-16^{\circ}C$ above room temperature was observed in the investigated system. It was found that the temperature increase in soil transported the pore water and metals from bottom to the topsoil. This vertical transport phenomenon is critical for the electrokinetic process to remediate in-situ deep pollution.

• 한국환경과학회지
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• 제29권11호
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• pp.1055-1064
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• 2020

In this research, heavy metals and T-P removal characteristics of plated wastewater are derived using BPC(Break Point Chlorination) process. AA sedimentation pond outflow(Influence) was evaluated for the removal efficiency of heavy metal(Ni) and T-P at a reaction time of 25 minutes by NaOCl input volume(9, 11, 13 and 15 mL). In the case, the higher the NaOCl input volumes, the higher the ORP values were maintained and the higher the removal efficiency tended to be. On the other hand, T-P was judged to have a low relationship between the ORP value and the removal efficiency. In addition, the efficiency of removal heavy metals and T-P in the plated wastewater by injecting 10 mL, 15 mL, 20 mL and 25 mL NaOCl, increased as the amount of NaOCl injected increased, the amount of NaOH input for pH increased. It was found that suspended solid in effluence also increased. It was also observed that the color of the plating wastewater changed from yellowish green to green to charcoal gray to black as the amount of NaOCl injected increased. Treatment characteristics of the reaction time, the longer the reaction time with the substance to be treated after the input of NaOCl, the more the heavy metal removal efficiency tended to increase. Through XRF analysis of the sludge, the constituents in the sludge such as NaCNO, CNCl, Na₃PO₄, CrO₄, 2Na₂CrO₄ and 2NaNO₃ will be analyzed in detail, and the mechanisms of the reaction between the plated wastewater and the complex compound will be elucidated.

• 유기물자원화
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• 제22권2호
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• pp.50-56
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• 2014

일반적으로 도금 폐수를 비롯한 산업 폐수 내 중금속 처리에 적용되는 응집-침전은 응집제의 비용과 침전 효율의 불안정성이라는 한계가 존재한다. 본 연구에서는 수산화물 생성-분리막 공정을 전제로 하여, pH와 교반조건에 따른 수용액 상의 중금속 제거 효율과 생성된 수산화물의 입도 분포를 고찰하였다. pH별 실험 결과, pH 9-10에서 최적의 중금속 제거 효율이 확인되었으며, 무기응집제인 $FeCl_3$의 투입은 오히려 제거 효율을 저하시켰다. 완속교반 시간 및 강도는 70 rpm, 20 min 조건이 최대 효율을 보였으며 Cu, Ni, Zn 모두 청정 지역 기준 폐수 배출 기준을 만족하였다. 나타났다. 생성된 중금속 수산화물의 입도 분석을 수행한 결과, 입자의 99.9 %가 $2{\mu}m$ 이상이었다.

• 청정기술
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• 제15권1호
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• pp.60-66
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• 2009

천연가스로부터 유기 황 화합물인 THT와 TBM의 흡착 제거를 위해 NaY 제올라이트계를 이용하여 흡착실험을 수행하였다. NaY에 대한 표면의 산-염기적 특성을 변화시키고 흡착능의 향상을 도모하기 위하여 Li, K, Fe, Co, Ni, Cu, Ag 등의 금속이온으로 이온교환하였으며, 이를 부취제 THT와 TBM의 흡착 제거에 적용하였다. 그 결과 Cu-NaY, Ag-NaY, NaY에서 다른 물질들에 비해 THT, TBM의 파과흡착량이 높게 나타났으며, Cu, Ag가 이온교환된 제올라이트의 증가된 산성적 특성 때문에 다른 이온들에 비해 높은 파과흡착량을 나타낸 것으로 사료되어진다. 산량이 Ag-NaY보다 높게 측정된 Cu-NaY의 경우, Cu의 담지량을 조절하였다. 이들 가운데 0.5 M의 질산구리 용액으로 이온교환된 Cu-NaY-0.5가 가장 높은 파과흡착량을 보였으며, THT에 대해 1.85 mmol-S/g, TBM에 대해 0.78 mmol-S/g을 각각 나타내었다. 그리고 THT의 탈착 활성화에너지는 NaY, Cu-NaY-0.5 두 물질에 대하여 큰 차이가 없었으며, TBM의 탈착 활성화에너지의 경우 Cu-NaY-0.5 흡착제에서 NaY보다 높게 측정되었다.

• 대한치과의사협회지
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• 제53권10호
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• pp.743-750
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• 2015

Objectives: This study compared the mechanical efficacy of sonic activated and passive ultrasonic irrigation for removing intracanal medicament from a simulated root canal under controlled conditions. Materials and Methods: Thirty simulated root canal in resin blocks were randomly divided into 3-groups. The canals were enlarged using ProTaper files and K3XF (#30/0.06). After cleaning and drying, canals were filled with Calcipex. Overfilled materials were wiped out and measured their weight to the unit of 1/10mg. After one week storage in 100% humidity $37^{\circ}C$ temperature, canals were irrigated using 20mL of saline with one of following methods according to the designated groups (n = 10). For group-NI, 30-gauge nickel-titanium irrigation needle was used. During irrigation with every 5mL, needle was moved in-and-out with 4-mm amplitudes. EndoActivator and ultrasonic tip were used for group-EA and group-UT respectively for 20 seconds after every 5mL irrigation using needle. Then the weight was measured again to calculate the weight of residual remnants. The data were analyzed by one-way ANOVA and Duncan's post-hoc test at a significance level of 95%. Results: The weight of the residual medicaments were $3.62{\pm}0.81mg$, $2.84{\pm}0.28mg$, and $2.73{\pm}0.90mg$ for group-NI, -EA, and -UT, respectively. Group-EA and group-UT had no significant differences to remove intracanal medicament and left significantly less amount of paste than group-NI (p < 0.05). Conclusions: Under the controlled conditions of this study, the sonic activation and PUI have similar mechanical efficacy for removing intracanal medicament.

• 한국환경농학회지
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• 제25권1호
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• pp.40-46
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• 2006

This study was initiated to evaluate the inhibitory effect of selected heavy metals on the growth of Acinetobacter sp. Down as one of the phosphorus accumulating microorganisms (PAO) involved in the enhanced biological phosphorus removal (EBPR) process of the wastewater treatment plant. Acinetobacter sp. was initially selected as a starting model microorganism and was grown under aerobic condition for this experiment. The heavy metals selected and investigated in this study were cadmium (Cd), copper (Cu), mercury (Hg), nickel (Ni), and zinc (Zn). Median $(IC_{50})$ and threshold $(IC_{10})$ inhibitory concentrations for Cd, Cu, Hg, Ni, and Zn were 2.95 and 1.45, 4.92 and 2.53, 0.03 and 0.02, 1.12 and 0.43, 14.84 and 5.46 mg $L^{-1}$, respectively. We demonstrated that most of heavy metals tested in the experiment inhibited the growth of Acinetobacter sp. in the range of predetermined concentrations. Based on the data obtained from the experiment, Hg was the most sensitive to Acinetobacter sp., then Ni, Cd, Cu, and Zn in order.

• 대한환경공학회지
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• 제29권12호
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• pp.1381-1389
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• 2007

중금속 폐수는 다양한 유독성 화합물과 함께 배출되므로 상수원, 토양, 지하수 등의 환경에 악영향을 야기 시킬 수 있다. 이러한 고농도의 복합중금속과 시안착염을 포함한 도금폐수 처리 시 일반적으로 잘 알려진 알카리염소법에 의한($1^{st}$ Oxidation: pH 10, reaction time 30 min, ORP 350 mV, $2^{nd}$ Oxidation: ORP 650 mV) 시안의 잔류농도에 대한 제거효율은 유입수의 시안농도 374 mg/L에 비해 처리 후 잔류시안농도는 3.74 mg/L로써 그 제거효율이 99%로써 상당히 높았으나 수질환경보전법상 수질배출허용기준(나 지역) 1 mg/L 이하에 만족하기 위해서는 2차, 3차 등의 고도처리가 요구됨을 알 수 있었고, 이에 아연백법 및 공침처리공정(reaction time: 30 min, pH: 8.0, rpm: 240)을 적용하여 용해되어 잔류하는 시안착염을 불용성염으로 침전시켜 처리한 결과 잔류시안농도가 1.0 mg/L 이하의 만족할 만한 결과를 있었다. 크롬의 처리는 6가 크롬을 3가 크롬으로 환원(pH: 2.0 max, ORP: 250 mV)시킨 후, 수산화물로 처리(pH: 9.5)시 무난히 99%의 최대 제거효율을 얻을 수 있었다. 폐수 중 나머지 동(Cu)과 니켈(Ni)처리는 황화물 응집침전법을 적용한 결과 최적 pH는 $9.0\sim10.0$에서 $Na_2S$의 최적주입량이 Cu의 경우 0.5 mol에서 99.1%, Ni의 경우 3.0 mol에서 99.0% 이상 제거할 수 있었다. 즉 중금속 복합폐수 중 시안착염은 알카리 염소산화처리법만으로는 수질환경보전법의 규제치 이하로 처리가 불가능 하였고 아연백법 및 공침공정을 같이 적용한 결과 규제치 이하로 처리가 가능하다는 것을 현장 확인할 수 있었다.