In this study, the removal efficiency of PFCs(perfluorinated compounds) in the GAC(granule activated carbon) process based on the superheated steam automatic regeneration system was investigated in laboratory scale and pilot-scale reactor. Among PFCs, PFHxS(perfluorohexyl sulfonate) was most effectively removed. The removal efficiency of PFCs was found to be closely related to the EBCT, and the removal efficiencies of PFOA(perfluorooctanoic acid), PFOS(perfluorooctyl sulfonate), and PFHxS were 43.7, 75, and 100%, respectively, under the condition of EBCT of 6 min. Afterward, PFOA, PFOS, and PFHxS exhibited the earlier breakthrough time in the order. After that, GAC was regenerated, and the removal efficiency of the PFCs before and after regeneration was compared. As a result, it was shown that the PFCs removal efficiency in the regenerated GAC process were higher, and that of PFOA was improved to 75%. The findings of this study indicate the feasibility of the superheated steam automatic regeneration system for the stable removal of the PFCs, and it was verified that this technology can be applied stably enough even in field conditions.
본 연구에서는 과불화합물 PFOA와 PFOS potassium salt가 Mesocentrotus nudus의 10 min-수 정률과 48 h-정상유생발생률에 미치는 독성영향을 반수영향농도, 무영향농도, 최소영향농도 등 의 독성값 계산을 통해 확인하였다. PFOA와 PFOS potassium salt에 대한 10 min-수정률의 EC50 값은 각각 1346.43 mg/l와 536.18 mg/l로 나타났으며, 48 h-정상유생발생률의 EC50 값은 각각 42.67 mg/l와 17.81 mg/l로 나타났다. 최근 연구에 의하면, 환경 내의 PFOA와 PFOS의 농도는 지속적으로 감소하였으며, 성게류에게 급성독성을 나타낼 정도는 아닌 것으로 나타났다. 하지 만 생물체내에서는 여전히 높은 농도로 관측되고 있다. 결국, PFOA와 PFOS는 생물체의 생애 전주기에 걸쳐 체내 축적이 가능하기 때문에, 연안환경에 서식하는 해양생물을 이용한 생애 전주기적 만성독성 연구가 필요할 것이다.
Adsorption by granule activated carbon(GAC) is recognized as an efficient method for the removal of perfluorinated compounds(PFCs) in water, while the poor regeneration and exchange cycles of granule active carbon make it difficult to sustain adsorption capacity for PFCs. In this study, the behavior of PFCs in the effluent of wastewater treatment plant (S), the raw water and the effluents of drinking water treatment plants (M1 and M2) located in Nakdong river waegwan watershed was monitored. Optimal regeneration and exchange cycles was also investigated in drinking water treatment plants and lab-scale adsorption tower for stable PFCs removal. The mean effluent concentration of PFCs was 0.044 0.04 PFHxS g/L, 0.000 0.00 PFOS g/L, 0.037 0.011 PFOA g/L, for S wastewater treatment plant, 0.023 0.073 PFHxS g/L, 0.000 0.00 PFOS g/L, 0.013 0.008 PFOA g/L for M1 drinking water treatment plant and 0.023 0.073 PFHxS g/L, 0.000 0.01 PFOS g/L, 0.011 0.009 PFOA g/L for M2 drinking water treatment plant. The adsorption breakthrough behaviors of PFCs in GAC of drinking water treatment plant and lab-scale adsorption tower indicated that reactivating carbon 3 times per year suggested to achieve and maintain good removal of PFASs. Considering the results of mass balance, the adsorption amount of PFCs was improved by using GAC with high-specific surface area (2,500m2/g), so that the regeneration cycle might be increased from 4 months to 10 months even if powdered activated carbon(PAC) could be alternatives. This study provides useful insights into the removal of PFCs in drinking water treatment plant.
The chemical structures of perfluorinated compounds(PFCs) have unique properties such as thermal and chemical stability that make them useful components in a wide variety of consumer and industrial products. Two of these PFCs, perfluorooctane sulfonate(PFOS) and perfluorooctanoic acid(PFOA), have received attention and were the most commonly detected. In this study it was analyzed the concentrations of 8 PFCs in samples were collected from drinking water treatment plants for 5 years(2012-2016). PFOS and PFOA were also high concentration and frequency. The mean concentrations of PFOA and PFOS were detected 0.0026-0.0069 μg/L and 0.0009-0.0024 μg/L in samples from drinking water treatment plants. These were relatively lower or similar compared to PFOS concentrations in Osaka(Japan). In general, these levels are below health-based values set by international authoritative bodies for drinking water. These results will be serve as the first monitoring data for PFCs in drinking water and be useful for characterizing the concentration distribution and management of PFCs in future studies.
Raw leachates from three landfills and treated leachates from two landfills on Jeju Isalnd were analyzed for ten perfluorinated compounds (PFCs) detected in aquaruc environments. The leachates were collected six times in 2014 and 2015. Among the ten PFCs, three were not detected, namely perfluoroundecanoic acid (PFUnDA), perfluorododecanoic acid (PFDoDA), and perfluorodecane sulfonate (PFDS). The total concentrations of PFCs ranged as 724-3313 ng/L (mean 1999 ng/L) in raw leachates and from less than the limit of quantification (LOQ) to 394 ng/L (mean 133.2 ng/L) in treated leachates. The domonant compounds measured were perfluorooctanoic acid (PFOA) (mean contribution 37.7%) and perfluorobutane sulfonate (PFBS) (mean contribution 38.2%) in raw leachates, and PFOA (mean contribution 40.7%), perfluorohexanoic acid (PFHxA) (mean contribution 27.3%) and PFBS (mean contribution 26.5%) in treated leachates. No significant correlations were observed between total/several individual PFCs and leachate pH and CODCr, which may be due to complex chemical nature of landfill leachates and characteristics of waste and landfills.
과불화합물(PFCs, Perfluorinated compounds, 이하 과불화화합물) 등은 발암성, 생식독성, 생농축성 등을 가지고 특히 장거리 이동성을 가지고 있는 대표적인 잔류성 유기오염물질로 분류되고 있다. 스톡홀름 협약은 사전예방 원칙에 입각하여 잔류성 유기오염물질로부터 인간의 건강 및 환경 보호를 목적으로 하는 국제협약으로 ’04년 5월 발효되었다. 우리나라는 ’01년 10월 협약에 서명한 후 협약가입을 위해 잔류성유기오염물질의 배출 실태를 파악하고, 관련 법규를 제정하는 등 협약가입 준비 후, ’07년 2월에 가입하였다. 제4차 스톡홀름협약 당사국총회에서 과불화옥탄술폰산(PFOS)과 그 염류 등은 규제 대상물질로 등재(’09.4)하였으며, PFOS의 경우 용도에 따라 항구적 면제(Acceptable purpose), 특정면제(Specific Exemption), 사용제한하고 있으며 PFOA는 스톡홀름협약 POPs 검토위원회(POPRC)에서 위해성 검토 중으로 규제예고 되어 있다. 하지만 국내에서는 최근 아웃도어용품 등의 방수 기능성 제품에서 과불화화합물이 검출되어 논란이 일어나는 등, 과불화화합물의 위해성에 대한 관심이 증대되고 있으나, 과불화화합물 함유 제품 및 폐기물의 관리체계는 초기 정비 단계로, 스톡홀름 협약의 이행 및 과불화화합물 함유 제품 및 폐기물의 체계적 관리가 필요한 시점이다. 이에 본 연구에서는 스톡홀름협약 이행과 과불화화합물 함유폐기물을 적정처리를 위해 과불화화합물의 생산・사용・폐기 등 전과정 물질흐름분석을 통해 정량적인 자료를 확보하고, 물질과 제품의 사용용도별 폐기물 관리체계를 마련하였다.
PFC (perfluorocompound) gases have an extremely high global warming potential (GWP). A study of the destruction of NF3, CF4 and SF6 gases emitted from the semiconductor industry was attempted by plasma power at 4.4 kW, 5.5 kW, 6.0 kW, 6.6 kW, 7.6 kW, 8.1 kW and 9.1 kW. As electric power increased, DRE (destruction and removal efficiency) of NF3, CF4 and SF6 was also increased. It was confirmed through experiment that the DRE of NF3 is 99% at 7.6 kW, 97% for CF4 at 9.14 kW and 100% for SF6 at 7.6 kW of plasma power. By-products formed by PFC destruction were mainly F2, SO2F2, NOx and CO gases. In addition, particulate matter was formed, and particle were proven to be AlF3.
신규의 환경오염물질로서 PFOS나 PFOA와 같은 과불화 화합물(perfluorinated compounds, PFCs)은 표면처리제, 계면활성제, 화제진압용 소화제 등 다양한 용도로 널리 사용된다. 하지만 이들 PFCs은 PBT(persistency, bioaccumulation, toxicity) 특성으로 인해 심각한 환경오염을 유발하고 있는 실정이다. 예를 들면, 오염원이 없는 극지방을 비롯한 거의 모든 환경매체에서 지속적으로 검출되는 것으로 알려져 있다. 그래서 PFCs의 연구는 매우 중요하다. 이 연구는 대표적인 영산강 수계인 황룡강과 영산강을 대상으로 10종의 PFCs를 정량적으로 측정하였다. 시료는 봄철과 가을철 두 번에 걸쳐 이루어졌고, 조사 지점은 총 19개 지점으로, 담양(1지점), 장성(2지점), 광주(6지점), 나주(3지점), 함평(3지점), 무안(1지점), 영암(1지점), 목포(1지점)이였다. 총 10종의 PFCs을 대상물질로 하여 LC-MS/MS를 사용하여 분석한 결과, PFOS (perfluorooctanesulfonate)가 8.24~115.34 ng/L (평균 41.6 ng/L), PFOA (perfluorooctanoate)가 4.02~8.86 ng/L (평균6.64 ng/L)로 검출되었다. 또한, PFNA(perfluorononanoate)는 두 번의 모니터링에서 모두 검출되지 않았고, PFHxS (perfluorohexanesulfonate)의 경우 평균농도가 1.47 ng/L로 PFOS/PFOA에 비해 비교적 낮은 농도로 검출되었다. 현재까지 영산강 수계에서 조사된 PFCs 모니터링한 결과는 조사지역에 따라 큰 차이를 보였으나, 타 지역 수계에 비해 농도가 낮은 것으로 나타났다. 결과적으로 PBT 특성을 갖고 있는 PFCs가 영산강 수계 전반에서 검출되고 있어서 지속적인 모니터링 연구조사를 수행해야 할 것으로 판단된다.
Perfluorooctanoic acid (PFOA) and perfluorooctyl sulfonate (PFOS) is a new persistent organic pollutants of substantial environmental concern. This study investigated the potential of magnetic ion exchange resin (MIEXⓇ) as the adsorbent for the removal of PFOA and PFOS from Nakdong River water. In our batch experiments, we studied the effect of some parameters (pH, temperature, sulfate concentration) on the removal of PFOA and PFOS. The results of sorption kinetics on MIEXⓇ show that it takes 90 min to reach equilibrium but the economical contact time and dosage were 30 min and 10 mL/L. An increase in pH (pH 6∼10) leads to a decrease in PFOA (2.0%) and PFOS (3.6%) sorption on MIEXⓇ. The sorption of both PFOA and PFOS decreases with an increase in ionic strength for sulfate ion (SO4 2-), due to the competition phenomenon. An increase in water temperature (8℃∼28℃) in water leads to a increase in PFOA (2.8%) and PFOS (4.3%) sorption on MIEXⓇ. Based on the sorption behaviors and characteristics of the adsorbents and adsorbates, ion exchange and hydrophobic interaction were deduced to be involved in the sorption, and hemi-micelles possibly formed in the intraparticle pores.