Exploring the complex removal behavior of natural organic matter upon N-doped reduced graphene oxide-activated persulfate via excitation-emission matrix combined with parallel factor analysis and size exclusion chromatography

Maqbool, Tahir,Bae, Sungjun,Hur, Jin Elsevier 2018 CHEMICAL ENGINEERING JOURNAL -LAUSANNE- Vol.347 No.-

<P><B>Abstract</B></P> <P>Metal-free oxidative degradation by persulfate (PS) is an emerging process as green chemistry without any toxic metal leaching to aquatic environments but has never been explored for natural organic matter (NOM) removal to date. In this study, nitrogen-doped reduced graphene oxide (NrGO) was applied as a catalyst first to investigate the degradation behavior of NOM. A parallel system was also examined without PS for non-oxidative interaction. For three tested NOM, the extent of the removal increased with the addition of NrGO, and the removal rates were consistently higher for the systems with versus without PS (by 25–102%). Specific ultraviolet absorbance (SUVA) exhibited declining trends with NrGO for both oxidative and non-oxidative systems. Up to 86.9%, 59.9%, and 60.3% reduction in SUVA values were found for the oxidative removal of Suwannee River natural organic matter, Suwannee River humic acid, and Suwannee River fulvic acid, respectively. The excitation-emission matrix combined with parallel factor analysis (EEM-PARAFAC) decomposed fluorescent NOM into two fulvic-like (C1 and C2) and two humic-like (C3 and C4) components. Results implied that more hydrophobic and more condensed aromatic NOM constituents might be preferably removed by both oxidation and adsorption with the greater removal tendency shown for the humic versus the fulvic-like components. Size exclusion chromatography (SEC) demonstrated that large size molecules were more effectively removed by the oxidative versus the non-oxidative interactions with NrGO. Comparative results revealed that adsorption likely played a critical role in determining the preferential removal tendency of the metal-free oxidation toward heterogeneous NOM structures.</P> <P><B>Highlights</B></P> <P> <UL> <LI> This study first explored metal-free oxidation of NOM. </LI> <LI> NrGO-driven PS activation effectively removed NOM via adsorption and oxidation. </LI> <LI> Preferential removal of aromatic and large size NOM molecules was found. </LI> <LI> Adsorption plays a critical role in NOM removal via a non-radical pathway. </LI> <LI> Humic-like fluorescence can be a good surrogate for tracking NOM removal. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

산성 및 유기성 가스의 동시제거를 위한 준건식 세정시스템의 적정 운전 조건

백경렬,구자공 한국환경과학회 2001 한국환경과학회지 Vol.10 No.1

The effect of major operating parameters in spray drying sorber(=SDS) for automatic control for the simultaneous removal of acidic and organic gaseous pollutants from solid waste incinerator was performed. The field experiment was carried out in pilot scale test for the quantification of major operating parameters of hydrophilic and the hydrophobic pollutants. The removal efficiencies of SO_2 and HCI in the 5wt% slurry condition were being increased with the increase of the stoichiometric ratio which is the molecular ratio of lime to the pollutant concentration, and with the decrease of inflow flue gas temperature in the pilot SDS reactor. The removal efficiency along the height of spray drying sorber was closely related to the temperature profile, and more than 90% of total removal efficiency was achieved in an absorption region. For the removal of acidic gas the optimum operating condition considering the economics and a stable operation is the 5wt% of slurry concentration, 1.2 of stoichiometric ratio and 250℃ of inflow flue gas temperature. For the organic gases of benzene and toluene the removal efficiencies were 20 - 60% which is much lower than that of acidic gas. The best removal efficiency was obtained at 1.5 of stoichiometric ratio and 250℃ of inflow flue gas temperature. The organic's removal efficiency along the height of spray drying sorber was quite different from that of acidic gas, that is, more than 60% of the total removal efficiency for benzene and 90% of the total removal for toluene were achieved in the dried adsorption region, which was formed at the lower or exit part of the reactor.

하수 고도처리시설의 유입 하수특성과 운전조건에 따른 인 제거특성 비교

김덕진 ( Duk-jin Kim ) 한국환경기술학회 2012 한국환경기술학회지 Vol.13 No.3

하수고도처리 시 인 제거는 불안정한 처리성능과 불확실한 운전관리방안으로 인해 화학적 처리법에 의존하는 경우가 많다. 하지만 적절한 운전조건하에서는 안정적인 생물학적인 인 제거가 가능하며, 이러한 생물학적인 인 제거는 슬러지의 유효이용과 자원의 회수측면에서도 유리한 방법이다. 실제 운영 중인 하수처리장 8개소를 대상으로 하여 생물학적 인 제거 실태를 분석하였고, OUR 실험을 통해서 질소·인 동시제거를 위한 최적운전조건을 파악하였다. 생물학적 인 제거의 최적조건은 유입 BOD농도 및 혐기조의 BOD-SS부하는 각각 100mg/L, 0.5g/g·day이상으로 나타났고, 유입수 중의 유기물 조성이 생물학적 인 제거에 큰 영향을 미치는 것으로 나타났다. 하지만 이러한 결과 이외에도 안정적인 생물학적 인 제거를 위해서는 질산화에 필요한 최소 SRT와 인 섭취에 필요한 최대 SRT를 고려하여 운전조건을 설정해야할 필요가 있다. The chemical phosphorus removal process has been most widely recommended for removing phosphorus from wastewater because the results of biological phosphorus removal process are unstable and the operating conditions are uncertain. However reliable biological phosphorus removal will be accomplished by adjusting the operating conditions. It is more favorable in terms of disposal of sludge and the recovery of resources from sludge. In this study, the characteristics of the biological phosphorus removal processes in the 8 full-scale advanced wastewater treatment plant were evaluated. Also OUR experiments were carried out to determine the optimum operating conditions for the simultaneous nitrogen and phosphorus removal. The optimum conditions of the influent BOD concentration and anaerobic BOD-SS loading rate in the biological phosphorus removal process were found to be over 100mg/L and 0.5g/g·day respectively. And the results showed that the biological phosphorus removal was influenced by the organic matter composition of influent. It is concluded that even if the other conditions are satisfied, operation conditions should be established by taking account of the minimum SRT for nitrification and maximum SRT for reliable biological phosphorus removal.

MLE 공정에서 PAC 응집제 첨가에 따른 질소 및 인 제거 효율 평가와 질신화 저해에 관한 연구

안찬현 ( Chan Hyun An ),전동걸 ( Dong Jie Tian ),임현숙 ( Hyun Sook Lim ),정진 ( Jin Chung ),전항배 ( Hang Bae Jun ) 충북대학교 건설기술연구소 2015 建設技術論文集 Vol.34 No.1

80 일간의 운전 결과 본 MLE 공정 내 Al(III) 계 응집재인 PAC 를 주입한 결과 유기물 제거에는 영향을 미치지 않는 것으로 나타났다. 다만 단일 반응조 내에서 Al(III) 이 수화물 및 침전물 형태로 장기적인 축적으로 미생물의 대사활동에 영향을 미친 것으로 보고되었지만 본 실험에서는 무산소조, 호기조 및 침전조 등 일련의 연속공정으로 구성한 결과 실제Al(III) 축적에 의한 영호t은 관찰되지 않았다. 또한 질소 재거에 있어서도 유기물과 마찬가지로 제거효율 영향은 거의 없다 즉, TN 제거효율은 각각 Run 1 70%, Run 2 73%, Run 3 78%이였으며, 마지막으로 Al/P몰비 5인 Run 4에서는 70% TN 제거효율을 나타내었다. 인의 경우 Run 1에서는 인 제거가 이루어지지 않음을 관찰할 수가 있다. 하지만 Al/P몰비를 3.6,4,5로 응집제를 주입한 Run 2, Run 3 및 Run 4에서는 각각 92%, 96%, 97%의 높은 인 제거효율을 나타내었다. 그 외 DO농도 3.0~4.0 mg/L의 조사결과로부터 농어촌진흥원 회분식 실험결과 Al/P 몰비 증가에 따라 NH4+-N 제거 속도는 마마하게 감소하였다. 즉, Al/P=0인 NH4+-N 제거 속도는 5.0 g-NH4+-N/kg -MLSS·hr 이었고, Al/P=3.6 및 Al/P=4일 경우에는 모두 4.9 g- NH4--N/kg-MLSS·hr이었으며, 마지막으로 Al/P=5일 경우에는 4.8 g- NH4+-N/kg -MLSS·hr 를 나타내었다. After 80 days of a continuous operation of a MLE(Modified Ludzack Ettinger) process, addition of PAC as a coagulant did not affect on COD removal. When Al(III) was hydrated and precipitated and they were accumulated for a long period of time in a single phase reactor, it has been reported that it might influence the microbial metabolism. However in this study Al(III) accumulation was not apparent in a series of anoxic-aerobic-clarification process. PAC coagulation did not affect the nitrogen removal as well TN removal efficiency was found to be 70%, 73 %, and 78% for Run 1, 2, and 3 respectively. At Run 4 with Al/P mole ratio of 5, 70% of TN was removed. In case of phosphorus, at Run 1 P was not removed. However when Al(III) was added as Al/P mole ratios of 3.6, 4, and 5, 92%, 96%, and 97% of P were removed respectively. When DO was 3.0~4.0 mg/L, as Al/P mole ratio increased NH4+,-N was removed insignificantly. In other word, when Al/P = 0, NH4+-N removal rate was 5.0 g-NH4+-N/kg-MLSS·hr. When AJ/P = 3.6 and AJ/P = 4, NH,+-N removal rate was 4.9 g-NH,+-N/kg-MLSS·hr for both cases. Finally when Al/P = 5, NH4+-N removal rate was 4.8 g-NH4+-N/kg-MLSS·hr.

Combination of ion exchange system and biological reactors for simultaneous removal of ammonia and organics

Park, Wooshin,Jang, Eunhee,Lee, Myun-Joo,Yu, Seungho,Kim, Tak-Hyun Elsevier 2011 Journal of environmental management Vol.92 No.4

<P><B>Abstract</B></P><P>A novel process for a simultaneous removal of ammonia and organics was developed on the basis of ion exchange and biological reactions. From batch experiments, it was found out that NH<SUB>4</SUB><SUP>+</SUP> could be removed effectively by combining cation exchange and biological nitrification showing 0.98 mg N/m<SUP>2</SUP>∙s of a maximum flux. On the other hand, the removal of NO<SUB>3</SUB><SUP>−</SUP> was 3.5 times faster than NH<SUB>4</SUB><SUP>+</SUP> and the maximum flux was calculated to be 3.4 mg N/m<SUP>2</SUP>∙s. The systems for NH<SUB>4</SUB><SUP>+</SUP> and NO<SUB>3</SUB><SUP>−</SUP> removal were combined for establishing the IEBR process. When the process was operated in a continuous mode, approximately 95.8% of NH<SUB>4</SUB><SUP>+</SUP> was removed showing an average flux of 0.22 mg N/m<SUP>2</SUP>·s. The removal efficiency of total nitrogen was calculated as 94.5% whereas that of organics was 99.5%. It was concluded that the IEBR process would be effectively used for a simultaneous removal of NH<SUB>4</SUB><SUP>+</SUP> and organics.</P>

Preparation of magnetic metal-organic frameworks with high binding capacity for removal of two fungicides from aqueous environments

Jiping Ma,Shuang Li,Gege Wu,Maryam Arabi,Feng Tan,Yafeng Guan,Jinhua Li,Lingxin Chen 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.90 No.-

A novel kind of Zr-based magnetic metal-organic frameworks (MMOFs) was prepared by immobilizationof UiO-66 onto Fe3O4@SiO2 particles via an efficient one-pot solvothermal method. Subsequently, it wasused for adsorptive removal of triclosan (TCS) and triclocarban (TCC) fungicides from aqueousenvironments by magnetic solid phase separation. Morphology and physical/chemical features of theMMOFs were fully characterized by XRD, SEM, TEM, FT-IR, and VSM etc., showing high specific surfacearea, appropriate functionality, and desirable magnetic property. Several main factors affecting theadsorption performances of TCS and TCC on the MMOFs were systematically investigated and optimized,such as pH value of water sample, amounts/types of adsorbent and salinity. Under the optimizedconditions, short adsorption equilibrium time (only 25 min) and outstanding saturated adsorptioncapacities (476.27 and 602.40 mg g 1 for TCS and TCC, respectively) were the remarkable superiorities ofthe MMOFs compared with that of most reported adsorbents. The MMOFs demonstrated excellentadsorption selectivity for TCS and TCC and anti-interference ability. Also, the reusability for at least 11cycles was another major profit of the MMOFs that saved cost and prevented waste. Moreover, theMMOFs demonstrated satisfactory removal/purification ability for actual environmental water samples. These benefits propounded a promising outlook of employing the MMOFs for influential removal ofpollutants with considerable reliability in thefield of wastewater treatment.

The simultaneous removal of sulfur dioxide and nitrogen dioxide by the limestone slurry with addition of organic acid additives

정지은,이창용 한국화학공학회 2021 Korean Journal of Chemical Engineering Vol.38 No.10

This study investigates the effects of organic acid on the simultaneous absorption of SO2 and NO2 in the packed column. Organic acids, i.e., formic acid, acetic acid, and propionic acid, were used as additives. In the case of the absence of additives, when SO2 and NO2 were simultaneously absorbed into the limestone slurry, both SO2 and NO2 contributed to increasing the mutual absorption efficiency. In the simultaneous absorption of SO2 and NO2 with addition of additives, the SO2 removal efficiency appeared in the order of formic acid<no addition<propionic acid<acetic acid. Acetic acid has a superior buffer capacity and intermediate hydrophobic interaction, resulting in the highest SO2 absorption efficiency. In the slurry with the addition of acetic acid and propionic acid, the reactions of absorbed SO2 and NO2 predominantly took place; thus, the SO4 2/SO3 2 ratio was greater than 1. In terms of formic acid, the slurry pH was maintained at approximately 4.0, which departs from the appropriate range, attributed to the small pKa value, showing a negative effect on SO2 and NO2 removal. In the slurry with formic acid added, the SO2 predominantly reacted with formic acid; hence, the SO4 2/SO3 2 ratio was less than 1.

생물학적 영양염류 제거를 위한 돈사폐수의 반응특성

한동준,류재근,임연택,임재명 江原大學校 附設 環境硏究所 1998 環境硏究 Vol.15 No.-

본 연구는 생물학적 영양염류제거에 있어 돈사폐수의 반응특성을 고찰하기 위하여 수행되었다.반응특성으로는 돈사폐수 욘존 COD의 약 66.1%는 생물학적 분해가 빨리 일어나는 유기물이였으며, 생물학적 분해가 불가능한 용존COD는 약 11~12%였다. 호기성 고정생물막 반응조에서 질소는 탈기 ,질산화, autotrophic,과 heterotrophic미생물의 세포합성으로 제거되었는데, 제거율은 각각 12.1%,68,9%15,0% 그리고 4.0%였다. 돈사폐수 This study was performed to investigate the reaction characteristics of piggery wastewater for biological nutrient removal. The reaction characteristics discussed the fraction of organics the behavior of nitrogen, nitrification, denitrification and the behavior of phosohorus. The fraction of readily soluble COD was 11~12 percent. The ammonia nitrogen was removed via stripping nitrification autotrophic cell synthsis and heterotrophic cell synthesis. The removal percents by each step were 12.1%, 68.9%, 15.0% and 4.0% respectively. Nitrification inhibition of piggery wastewater was found to occur at an in fluent volumetric loading rate over 0.2 NH_(3)-Nkg/㎥/d. Denitrification rates were the highest in the raw wastewater and the lowest in the anaerobic effluent. The denitritation of piggery wastewater came out to be possibe, and the rate of organic carbon consumption deceased about 10 percent The phosphorus removed was released in the form ortho-p in the aerobic fixed biofilm reactor it was caused by autooxidation. The synthesis and release of phosphorus were related to the ORP and the boundary value for the phase change was about 170mV. In the synthesis phase, the phosphorus removal rate per COD removed was 0.023mgP_(ayn)/mgCOD_(rem) The phosphorus contents of the microorganism were 4.3~6.0% on a dry weight basis

Effect of Template Removal on Synthesis of Organic-Inorganic Hybrid Mesoporous MCM-48

Ya Nan Zhao, San Xi Li,Chong Soo Han,San Xi Li 대한화학회 2012 Bulletin of the Korean Chemical Society Vol.33 No.10

Post-synthesis is used to synthesize organic hybrid inorganic mesoporous sieves. In this method, the activity and structure of the base sieve are crucial to obtain the definable hybrid materials. The chemical and physical properties of the base can be largely changed either by the final step of its synthesizing processes, by template removal which is accomplished with the oxidative thermal decomposition (burning) method or by solvent extraction method. In this paper we compared two methods for the post-synthesis of organic hybrid MCM-48. When the template was extracted with HCl/alcohol mixture, the final product showed larger pore size, larger pore volume and better crystallinity compared to the case of the thermal decomposition. The reactivity of the surface silanol group of template free MCM-48 was also checked with an alkylsilylation reagent CH2=CHSi(OC2H5)3. Raman and 29Si NMR spectra of MCM-48 in the test reaction indicated that more of the organic group was grafted to the surface of the sample after the template was removed with the solvent extraction method. Direct synthesis of vinyl-MCM-48 was also investigated and its characteristics were compared with the case of post-synthesis. From the results, it was suggested that the structure and chemical reactivity can be maintained in the solvent extraction method and that organic grafting after the solvent extraction can be a good candidate to synthesize a definable hybrid porous material.

Effect of Template Removal on Synthesis of Organic-Inorganic Hybrid Mesoporous MCM-48

Zhao, Ya Nan,Li, San Xi,Han, Chong-Soo Korean Chemical Society 2012 Bulletin of the Korean Chemical Society Vol.33 No.10

Post-synthesis is used to synthesize organic hybrid inorganic mesoporous sieves. In this method, the activity and structure of the base sieve are crucial to obtain the definable hybrid materials. The chemical and physical properties of the base can be largely changed either by the final step of its synthesizing processes, by template removal which is accomplished with the oxidative thermal decomposition (burning) method or by solvent extraction method. In this paper we compared two methods for the post-synthesis of organic hybrid MCM-48. When the template was extracted with HCl/alcohol mixture, the final product showed larger pore size, larger pore volume and better crystallinity compared to the case of the thermal decomposition. The reactivity of the surface silanol group of template free MCM-48 was also checked with an alkylsilylation reagent $CH_2=CHSi(OC_2H_5)_3$. Raman and $^{29}Si$ NMR spectra of MCM-48 in the test reaction indicated that more of the organic group was grafted to the surface of the sample after the template was removed with the solvent extraction method. Direct synthesis of vinyl-MCM-48 was also investigated and its characteristics were compared with the case of post-synthesis. From the results, it was suggested that the structure and chemical reactivity can be maintained in the solvent extraction method and that organic grafting after the solvent extraction can be a good candidate to synthesize a definable hybrid porous material.