산화 및 알칼리 후처리의 땅콩 껍질 바이오차를 이용한 철과 크롬 제거에 미치는 영향

서혜린(Hye-Lin Seo),인태연(Tae-Yeon Yin),권오인(Oh-In Kwon),전강민(Kangmin Chon) 대한환경공학회 2020 대한환경공학회지 Vol.42 No.2

목적 : 본 연구의 주요 목적은 단순 열분해를 통해 생산된 땅콩 껍질 바이오차(PB), KMnO₄ 후처리를 한 바이오차(PB-Ox), KMnO₄와 KOH 후처리를 한 바이오차(PB-Ox-A)에 의한 3가 철과 6가 크롬의 제거효율을 비교하는 것이다. 방법 : PB, PB-Ox, PB-Ox-A에 의한 3가 철과 6가 크롬의 제거기작을 알아보기 위하여 반응 동역학 모델과 흡착등온식 모델을 적용하였다. 또한, 다양한 변수들이 3가 철과 6가 크롬 흡착에 미치는 영향을 알아보기 위하여 투입량(0.8 - 2.4 g/L), 온도(15 - 35℃) 및 이온강도(0.05 - 0.2 M NaNO₃) 조건을 변화시키면서 흡착실험을 수행하였다. 결과 및 토의 : PB-Ox-A는 PB와 PB-Ox보다 중금속 흡착에 연관된 표면 작용기(O/C of PB = 0.064; O/C of PB-Ox= 0.058; O/C of PB-Ox-A = 0.188)가 잘 발달되었고, 더 넓은 표면적(PB = 351.5 m²/g; PB-Ox = 344.0 m²/g; PB-Ox-A = 2121.5 m²/g)과 공극(PB = 0.15 cm³/g; PB-Ox = 0.15 cm³/g; PB-Ox-A = 0.96 cm³/g)으로 인해 3가 철과 6가 크롬의 제거율이 높았다. PB, PB-Ox, PB-Ox-A의 투입량이 증가할수록 대상 중금속들에 대한 높은 제거율을 나타냈고, PB-Ox-A가 PB와 PB-Ox보다 높은 제거율을 나타내었다. PB, PB-Ox, PB-Ox-A에 의한 3가 철과 6가 크롬 제거는 유사 1차 속도모델보다 유사 2차 속도모델에 적합한 것으로 보아 화학적 흡착에 대한 특성을 따르는 것으로 나타났으며, PB, PB-Ox, PB-Ox-A를 이용한 3가 철과 6가 크롬의 제거는 모두 Freundlich 등온흡착모델에 적합한 것으로 보아 다층 흡착을 따르는 것으로 판단된다. 온도변화에 따른 PB, PB-Ox, PB-Ox-A에 의한 3가 철과 6가 크롬의 제거율의 변화는 크지 않는 것으로 나타났다. 바이오차에 의한 3가 철의 제거는 이온강도변화에 크게 영향을 받지 않았지만, 6가 크롬의 경우 이온강도가 증가할수록 제거율이 감소하였다. PB, PB-Ox, PB-Ox-A를 비교하였을 때 3과 철과 6가 크롬의 제거에 대해 PB-Ox-A가 가장 좋은 흡착제라는 것을 확인할 수 있었다. 결론 : 본 연구는 KMnO₄(산화)및 KOH(알칼리) 후처리가 표면특성 개선을 통하여 땅콩 껍질 바이오차의 중금속 흡착효율을 향상시킬 수 있다는 것을 입증하였다. 또한, 다양한 조건에서 PB, PB-Ox, PB-Ox-A에 의한 중금속 흡착 메커니즘을 조사한 결과 중금속의 물리화학적 특성과 흡착제의 표면 특징들이 PB, PB-Ox, PB-Ox-A의한 3가 철과 6가 크롬의 흡착에 중요한 역할을 하는 것으로 나타났다. Objectives : The main goal of this study was to compare the removal efficiency of trivalent iron and hexavalent chromium by peanut shell biochars (i.e., PB), post-treated peanut shell biochars using KMnO₄ (i.e., PB-Ox), and secondary post-treated peanut shell biochars using KOH (i.e., PB-Ox-A). Methods : The adsorption mechanisms of trivalent iron and hexavalent chromium by PB, PB-Ox, and PB-Ox-A were investigated using two types of adsorption kinetic and isotherm models. Furthermore, the adsorption experiments were performed under different adsorbent dosages (0.8 - 2.4 g/L), temperatures (15 - 35℃) and ion strengths (0.05 - 0.2 M NaNO₃) to identify their effects on the adsorption of trivalent iron and hexavalent chromium by PB, PB-Ox, and PB-Ox-A. Results and Discussion : Trivalent iron and hexavalent chromium could be more effectively removed by PB-Ox-A than PB and PB-Ox because of its higher contents of oxygen containing functional groups (O/C of PB = 0.064; O/C of PB-Ox = 0.058; O/C of PB-Ox-A = 0.188), higher surface area (PB = 351.5 m²/g; PB-Ox = 344.0 m²/g; PB-Ox-A = 2121.5 m²/g), and greater pore volume (PB = 0.15 cm³/g; PB-Ox = 0.15 cm³/g; PB-Ox-A = 0.96 cm³/g). The removal efficiencies of trivalent iron and hexavalent chromium by PB, PB-Ox and PB-Ox-A were increased with increasing the adsorbent dosages (PB-Ox-A > PB-Ox > PB). The adsorption kinetic experiments demonstrated that the pseudo second order rate model was suitable for the removal of trivalent iron and hexavalent chromium by PB (R² of Fe<SUP>3+</SUP> = 0.99; R² of Cr<SUP>6+</SUP> = 0.99), PB-Ox (R² of Fe<SUP>3+</SUP> = 0.98; R² of Cr<SUP>6+</SUP> = 0.98), PB-Ox-A (R² of Fe<SUP>3+</SUP> = 0.99; R² of Cr<SUP>6+</SUP> = 0.99). Furthermore, the removal of trivalent iron and hexavalent chromium using PB, PB-Ox and PB-Ox-A was well fitted to the Freundlich isotherm absorption model (R² of Fe<SUP>3+</SUP> = 0.997 - 0.999;R² of Cr<SUP>6+</SUP> = 0.995 - 0.998). The changes of temperature did not show significant effects on the removal of trivalent iron and hexavalent chromium by PB, PB-Ox, and PB-Ox-A. The removal efficiency of trivalent iron by PB, PB-Ox and PB-Ox-A was not influenced by the ionic strength whereas the removal efficiency of hexavalent chromium by PB, PB-Ox and PB-Ox-A was considerably decreased with increasing the ionic strength. These observations are evident that PB-Ox-A is the most effective adsorbent for the removal of trivalent iron and hexavalent chromium. Conclusions : The proposed post-treatment procedures might improve the surface properties of peanut shell biochars intimately associated with the removal of trivalent iron and hexavalent chromium. The physicochemical properties of the heavy metals and the biochars were found to be key factors governing the adsorption mechanisms of trivalent iron and hexavalent chromium by PB, PB-Ox and PB-Ox-A.

수용성 6가크롬을 흡입 노출 시킨 랫드의 체액과 적혈구중 크롬간의 관련성 연구

김광종,김현영,윤수종,이은일 한국산업위생학회 2001 한국산업보건학회지 Vol.11 No.1

The goal of this study was to evaluate the relationship between ambient hexavalent chromium concentration and the concentration of the chromium in-whole blood, plasma, erythrocytes, and its urinary excretion of male rats after inhalation exposure of sodium chromate during 1, 2, and 3 weeks. 1. Differences of mean chromium concentration in urine, whole blood, erythorocytes, and plasma of male rats exposed to sodium chromate by exposure level were statistically significance, respectively. 2. At low and high exposure groups, differences of mean chromium concentration in urine, whole blood, erythrocytes, and plasma of male rats by duration of inhalation exposure were statistically significance, respectively. 3. Ratio of whole blood chromium to plasma chromium increased with the incrased duration of inhalation expousre of sodium chromate. 4. Ambient hexavalent chromium was positively and strongly correlated with in erythrocyte chromium, and also erythrocyte chromium was strongly correlated with in whole blood chromium. In conclusion, this study showed that chromium in erythrocyte increased with the increased exposure level and exposure duration, therefore this study suggest that chromium in erythrocytes is a good biological exposure index of the internal dose from exposure to soluble hexavalent chromium compound.

Hexavalent chromium as a cathodic electron acceptor in a bipolar membrane microbial fuel cell with the simultaneous treatment of electroplating wastewater

Kim, Changman,Lee, Cho Rong,Song, Young Eun,Heo, Jinhee,Choi, Sung Mook,Lim, Dong-Ha,Cho, Jaehoon,Park, Chulhwan,Jang, Min,Kim, Jung Rae Elsevier 2017 CHEMICAL ENGINEERING JOURNAL -LAUSANNE- Vol.328 No.-

<P><B>Abstract</B></P> <P>Hexavalent chromium wastewater is produced in electroplating processes and the heavy metal industry, highlighting the need for an environmentally friendly treatment and the recovery of chromium. This study compared the performance of microbial fuel cells implemented with a proton exchange membrane (PEM-MFC) and a bipolar membrane (BPM-MFC) using hexavalent chromium from electroplating wastewater as the catholyte. The removal of hexavalent chromium and simultaneous bioelectricity generation were enhanced significantly using a BPM. On the other hand, in the PEM-MFC, the lower pH of the electroplating wastewater (pH 1.8) in the cathodic chamber decreased the anodic pH due to proton diffusion through the PEM, and inhibited the bioelectrochemical reaction. Scanning electron microscopy showed that the reduced chromium particles precipitated on the cathode carbon electrode during the MFC operation. The precipitate was identified as amorphous chromium oxide particles by energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Electroplating hexavalent chromium wastewater was treated in the cathode of MFC. </LI> <LI> A bipolar membrane MFC significantly improve the removal efficiency of Cr<SUP>6+</SUP>. </LI> <LI> Simultaneous higher bioelectricity was obtained from bipolar membrane (BPM). </LI> <LI> The BPM supports cathodic reaction without pH decrease in anodic chamber. </LI> <LI> The reduced chromium particles precipitated on the cathode surface was identified. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

산업부산물을 이용하여 제조된 시멘트 클링커의 수용성 6가 크롬 용출 특성

이정희,추용식,송훈,이종규,Lee, Jung-Hui,Chu, Yong-Sik,Song, Hoon,Lee, Jong-Kyu 한국재료학회 2010 한국재료학회지 Vol.20 No.4

Since it was developed by Joseph Aspdin, cement has been a common construction materials up to the present time. However, there are trace constituents in cement clinker. One of the trace constituents included in cement clinker, chromium, has become prominent and highly noticed lately as a social issue both inside and outside of this country because it affects the human body negatively. The aim of the present study was to investigate the concentration of water-soluble hexavalent chromium in cement clinker by using industrial by-products. For that reason, raw materials were prepared to add different $SiO_2$, $Al_2O_3$, and $Fe_2O_3$ sources. After the raw materials such as the limestone, the sand and the clay, iron ore was pulverized and mixed, and the raw meal was burnt at about $1450^{\circ}C$ in a furnace with an oxidizing atmosphere. The part in the raw materials of the clinker was substituted with slag, sludge, etc. and this was used to manufacturing cement clinker. To investigate the water-soluble hexavalent chromium content in clinker, raw meal was prepared by changing the modulus, the type, and the content of clinker materials and tested concentrations of hexavalent chromium in the clinkers. To determine $Cr^{+6}$ formation of the clinker, tests were done with raw meals adding chromium by using different industrial by-products. Consequently because the chromium was to be included in the raw materials of the clinker, production of Portland cement clinker was included with the chromium. Also, the chromium was converted into hexavalent chromium in the burning process.

클링커 제조 조건에 따른 수용성 6가 크롬 용출 특성

이종규,추용식,송훈,Lee, Jong-Kyu,Chu, Yong-Sik,Song, Hun 한국재료학회 2011 한국재료학회지 Vol.21 No.12

One of the trace constituents included in cement clinker, chromium, has become prominent and highly noticed lately as a social issue both inside and outside of this country because it affects the human body negatively. The purpose of the present study was to investigate leaching properties of water-soluble hexavalent chromium by different manufacturing conditions of cement clinker. Raw materials were prepared to add different $SiO_2$, $Al_2O_3$ and $Fe_2O_3$ sources. After the raw materials, such as limestone, sand and clay, iron ore was pulverized and mixed, and the raw meal was burnt at $1450^{\circ}C$ in a furnace with an oxidizing atmosphere. Leaching of soluble hexavalent chromium showed a tendency to decrease with an increasing LSF and IM. However, leaching of soluble hexavalent chromium increased with an increasing S.M. Alkali contents of iron source minerals is closely related to the leaching properties of soluble hexavalent chromium. Green sludge has the highest content of alkali added; leaching of water-soluble hexavalent chromium was mostly high. In order to reduce the water-soluble hexavalent chromium in cement, reducing the alkali content in raw materials is important.

페놀 화합물의 Hexavalent Chromium독성에 대한 세포 보호효과

한두석,강정일,백승화,Han, Du-Seok,Kang, Jeong-Il,Baek, Seung-Hwa 대한예방한의학회 2009 대한예방한의학회지 Vol.13 No.2

Objectives : In order to evaluate the cytotoxicity of hexavalent chromium, the cytoprotective effect of phenolic compounds against hexavalent chromium-induced cytotoxicity, cell viability, cell adhesion ability, lactate dehydrogenase(LDH) activity, and morphological changes of cells were examined. Methods : We measured the cytotoxicity of hexavalent chromium with 3-[4,5-dimethyl-thiazol-2-yl]-2,5-diphenyltetrazolium bromide(MTT), 2,3-bis-[2-methoxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-caboxanilide (XTT), LDH and DPPH methods. Results : The cytotoxicity of hexavalent chromium($IC_{50}$, $44.0-51.0{\mu}M$) was high according to the toxic criteria. Cytoprotective effect of phenolic compounds against $IC_{50}$ value of hexavalent chromium in cell morphology increased in a concentration-dependent manner. Conclusions : These results suggest that 3,4,5-trihydroxybenzoic acid may be used as a cytoprotective agent against chromium(IV)-mediated cytotoxicity.

일부 6가 크롬 폭로 작업자의 임파구 자매염색분체교환

신동훈,윤능기,서석권,예민해,Shin, Dong-Hoon,Yoon, Nung-Ki,Suh, Suk-Kwon,Yeh, Min-Hae 대한예방의학회 1990 예방의학회지 Vol.23 No.3

1989년 11월부터 4개월간 대구시내 소재 일부, 6가 크롬(삼산화크롬)으로 피막처리하는 도금작업장의 남성근로자를 대상으로 비중격천공이 있는 근로자 12명과 비중격천공이 없는 근로자 12명을 폭로군으로 하고 크롬에 폭로된 적이 없는 정상인 20명을 대조군으로 하여 개별면담을 통해 연령, 직업력, 흡연습관을 파악하였으며, 정맥혈을 채취하여 원자화 무염광로를 부착한 원자흡광도계로 혈중 크롬농도를 측정하였으며 말초혈액 중 임파구의 자매염색분체교환의 발현빈도를 조사하고 연령, 흡연습관, 직업력 및 혈중 크롬농도 등이 임파구 자매염색분체교환의 발현빈도에 미치는 영향을 조사했다. 크롬 도금작업의 말초혈액 중 임파구 자매염색분체교환의 발현빈도는 비중격 천공이 있는 군이 $10.1{\pm}1.6$, 비중격천공이 없는 군이 $8.5{\pm}3.4$이었고 대조군 $6.1{\pm}2.1$으로 세군간에 유의한 차이가 있었으며 (p<0.01), 비중격천공 군에서 가장 높은 빈도를 보였으며, 대조군에 비해 1.7배의 높은 빈도를 나타냈다. 혈중 크롬농도는 대조군이 $0.060{\pm}0.043{\mu}g/ml$, 크롬도금 작업자 중 비중격천공이 있는 군 $0.114{\pm}0.030{\mu}g/ml$, 비중격천공이 없는 군 $0.090{\pm}0.050{\mu}g/ml$로 세군간의 차이는 유의하였다 (p<0.01). 크롬도금 작업자와 대조군 모두 연령군별, 흡연습관별 및 근속년수에 따른 자매염색분체교환의 발현빈도에는 유의한 차이가 없었다. 혈중 크롬농도와 자매염색분체교환 발현빈도의 상관성은 상관계수, r=0.007로서 상관관계가 없었다 (Y=0.638 X+0.191, r=0.007. p>0.05). SCE 평균 발현빈도를 $y=(sum\;SCE)^{\frac{1}{2}}+(sum\;SCE+1)^{\frac{1}{2}}$를 이용하여 변형한 변수 y에 대해 연령, 흡연습관, 직업 및 혈중 크롬농도의 요인들로서 설명력은 32.3%였으며 가장 중요한 변수는 직업으로 나타났다. 이상의 결과로 보아 직업적인 크롬폭로에 의한 유전적 손상의 위험성이 어느 정토 있을 것으로 추측되며 생물학적 독성검정 지표로서 유용성이 있을 것으로 생각된다. To investigate the possibility of utilizing of sister chromatid exchange(SCE) analysis in lymphocytes as an indicator which could evaluate the effects of mutagenicity after in vivo exposure to hexavalent chromium, this study was conducted using some of chromium plating workers occupationally exposed to hexavalent chromium, chromium trioxide ($CrO_3$) in Taegu city. The study population was 12 Cr platers with perforation of nasal septum, 12 Cr platers without perforation of nasal septum and 20 controls. The SCE in peripheral blood lymphocytes of the subjects was analyzed and blood chromium concentration was estimated using the atomic absorption spectrophotometer (IL551) equipped with furnace atomizer (IL755). The mean SCE frequencies for Cr platers with and without perforation of nasal septum were statistically higher than those for control. The difference in SCE frequencies by age, smoking habits were not statistically significant both in Cr platers and controls. There was no difference in SCE frequencies by career of Cr platers workers. In Cr platers, the correlation between the mean SCE frequencies and chromium concentration in blood was not statistically significant. Using the transformation $y=(sum\;SCE)^{\frac{1}{2}}+(sum\;SCE+1)^{\frac{1}{2}}$, when the data was studied by multiple regression, it appeared that the influence of the occupation was the most important. Age, smoking, occupation and CrB(blood chromium concentration) together explain only 32.3% of interpersonal variation on SCE. The results in this study suggest tt a genetic risk due to occupationally exposure to hexavalent chromium is clearly inferable and thus, SCE analysis in human lymphocytes may be used indicator of biological toxic effects of chromium. Further, populatio analysis stuies are required before SCE frequency can be used as a mutagenic indicator in human population.

초음파를 조사한 마그네타이트의 크로뮴 제거

김수진 ( Su-jin Kim ),이지영 ( Ji-young Lee ),강민구 ( Min-koo Kang ),이상일 ( Sang-ill Lee ) 한국수처리학회 2017 한국수처리학회지 Vol.25 No.2

The purpose of this paper is to remove chromium by using magnetite irradiated with ultrasonic waves. Also we were investigated to evaluate this magnetite`s ability in treating total chromium and hexavalent chromium. In this study, it was evaluated to chromium removal efficiency by dosage, pH, sonication time. In case of hexavalent chromium, the optimum condition was dosage 10 mL, pH 2. And in case total chromium of mixed wastewater, the optimum condition was dosage 20 mL, pH 6. In case of sonication time, chromium removal efficiency was slightly increased to 6 hr. However the removal efficiency was decrease at higher than 6 hr.

Caliper Piston의 친환경 고 기능성 산질화 표면처리 적용 개발

김대열(Dae-yeol Kim) 한국자동차공학회 2016 한국자동차공학회 학술대회 및 전시회 Vol.2016 No.11

Brake Caliper Piston function is transmit the Clamping Force to Brake pad. In general, the caliper piston hard chromium-plating surface treated on carbon steel because of wear resistance. Chromium-plating is excellent wear resistance, lubricity, heat resistance, good corrosion resistance, has a view of the appearance no color change in the atmosphere is high. However, Hard chromium-plating using hexavalent chromium bath is widely used in various industries. Because of the serious health and environmental problems of hexavalent chromium, many attempts to alternate the hexavalent chromium plating. In this study we apply an eco-environment Oxy-nitride treatment in Caliper Piston and evaluated properties. In the evaluation results is oxy-nitride layer of 20㎛ thickness, it was given the good wear resistance performance. The outermost layer of oxy nitride was porous was produced porous ε-Nitride Fe2-3N (hexagonal). This Structure layer that improves lubricity and corrosion resistance. Result of Salt Spray test, the Property of Corrosion Resistance is Twiece than Hard chromium-plating Piston.

연속배양 체제에서의 침출수 미생물에 의한 6가 크롬이온의 환원

김현영,오영숙,김영관,최성찬,Kim, Hyoun-Young,Oh, Young-Sook,Kim, Yeong-Kwan,Choi, Sung-Chan 한국미생물학회 1998 미생물학회지 Vol.34 No.3

침출수 미생물에 의한 크롬 6가이온의 3가이온으로의 환원을 회분식 배양 및 실험실 규모의 연속배양체제에서 연구하였다. 회분식 배양에 있어서 다양한 범위는 침출수 (10~60%)와 glucose (50~200 mM)를 첨가한 최소배지에서 초기 농도 $20mg\;L^{-1}$의 크롬(VI)을 첨가한 경우 72시간내에 최대 90%의 크롬(VI)이 침출수 미생물에 의하여 환원되었다. 이때 glucose의 첨가는 크롬환원을 촉진시켰으나, 배지내 침출수 비율의 증가는 오히려 크롬환원을 저해하였다. 후자의 경우는 침출수에 존재하는 황산이온이 크롬이온과 경쟁적 저해를 일으키기 때문인 것으로 추정되었다. 연속배양 실험은 124일간 상온에서 크롬(VI)의 농도를 $5{\sim}65mg\;L^{-1}$로 증가시키면서 수행하였으며, 수리학적 체류시간이 36시간일 때 $5{\sim}50mg\;L^{-1}$의 크롬농도 범위에서의 환원은 거의 100%에 달하는 것으로 나타났다. 평균 81.2%의 환원효율을 보인 101~124일 구간에서 계산된 specific reduction rate는 $3.492mg\;g^{-1}\;protein\;h^{-1}$였다. 이상의 결과는 침출수에 존재하는 미생물이 크롬은 함유한 다양한 침출수 또는 피혁폐수의 크롬 무독화과정에 유용하게 쓰일 수 있다는 가능성을 제시해 주는 것이다. Reduction of hexavalent chromium to its trivalent form by leachate microorganisms was studied in batch and bench-scale continuous stirred tank reactor. The inoculum was a culture of microorganisms in leachate and capable of providing up to 90% chromate reduction during 72 h batch assay with $20mg\;Cr(VI)\;L^{-1}$ in minimal media containing different levels of leachate (10 to 60%) and glucose (50 to 200 mM). Addition of glucose increased the efficiency of chromate reduction, but adverse effect was observed with increase of leachate probably due to the competitive inhibition between chromate and sulfate ions. The continuous culture experiment was conducted for 124 days using synthetic feed containing different levels of chromate (5 to $65mg\;L^{-1}$) at room temperature. With a hydraulic retention time of 36 h, chromate reduction efficiency was mostly 100% when Cr(VI) concentrations in the reactor were in the range of 5 to $50mg\;L^{-1}$ Specific rate of Cr(VI) removal was calculated as $3.492mg\;g^{-1}\;protein\;h^{-1}$ during the period of 101~124 days from the start-up which showed 81.2% of average reduction efficiency. The results indicate the potential application of using leachate microorganisms for detoxification of hexavalent chromium in various chromium-contaminated wastewater from landfill or tannery sites.