한강을 원수로 하는 오존/과산화수소 고도정수처리공정에서의 MIB제거 및 잔류오존 농도에 관한 연구

( Stephen R. Mcadams ),구본진 ( Bon Jin Koo ),장명훈 ( Myung Hoon Jang ),이성규 ( Sung Kyoo Lee ) 한국물환경학회 2012 한국물환경학회지 Vol.28 No.5

This paper provides a detailed account of pilot testing conducted at South Lake Tahoe (California), the Ddukdo (Seoul) water treatment plant (WTP) and the Bokjung (Seongnam) WTP between February, 2010, and February, 2012. The objectives were first, to characterize the reactions of ozone with hydrogen peroxide (Peroxone) for Han River water following sand filtration, second to determine empirical ozone and hydrogen peroxide doses to remove a taste-and-odor surrogate 2-methylisoborneol (MIB) using an advanced oxidation process (AOP) configuration and third, to determine the optimum dosing configuration to reduce residual ozone to a safe level at the exit of the process. The testing was performed in a real-time plant environment at both low- and high seasonal water temperatures. Experimental results including ozone decomposition rates were dependent on temperature and pH, consistent with data reported by other researchers. MIB in post-sand-filtration water was spiked to 40-50 ng/L, and in all cases, it was reduced to below the specified target level (7 ng/liter) and typically non-detect (ND). It was demonstrated that Peroxone could achieve both MIB removal and low effluent ozone residual at ozone+hydrogen peroxide doses less than those for ozone alone. An empirical predictive model, suitable for use by design engineers and operating personnel and for incorporation in plant control systems was developed. Due to a significant reduction in the ozone reaction/decomposition at low winter temperatures, results demonstrate the hydrogen peroxide can be “pre-conditioned”1) in order to increase initial reaction rates and achieve lower ozone residuals. Results also indicate the method, location and composition of hydrogen peroxide injection is critical to successful implementation of Peroxone without using excessive chemicals or degrading performance.

항생제 내성: 얼마나 심각한 문제이고, 어떻게 해결할 수 있는가?

Alexander J. McAdam,David C. Hooper,Alfred DeMaria,Brandi M. Limbago,Thomas F. O’Brien,Betsy McCaughey 대한진단검사의학회 2013 Laboratory Medicine Online Vol.3 No.2

Electrochemically generated bimetallic reductive mediator Cu¹⁺[Ni²⁺(CN)₄]¹⁻ for the degradation of CF₄ to ethanol by electro-scrubbing

Muthuraman, G,Ramu, AG,Cho, YH,McAdam, EJ,Moon, IS SAGE Publications 2018 Waste management & research Vol.36 No.11

Sustainable degradation of carbon tetrafluoride to non-corrosive useful products by incorporating reduced electron mediator within electro-scrubbing

Muthuraman, G.,Ramu, A.G.,Cho, Y.H.,McAdam, E.J.,Moon, I.S. Elsevier 2018 Journal of industrial and engineering chemistry Vol.63 No.-

<P><B>Abstract</B></P> <P>The degradation of CF<SUB>4</SUB> gas using existing technologies produces other types of greenhouse gas (CO<SUB>2</SUB>) and corrosive side products. The main aim of this study is to degrade CF<SUB>4</SUB> gas at room temperature into useful products without producing corrosive side products by mediated electrochemical reduction (MER) process using an electrogenerated Cu<SUP>1+</SUP>[Ni<SUP>2+</SUP>(CN)<SUB>4</SUB>]<SUP>1−</SUP> mediator. Initial studies on the electrolytic reduction of the hetero-bimetallic complex in catholyte solution at anodized Ti cathode was monitored by oxidation/reduction potential (ORP) variation whether the Cu<SUP>2+</SUP> or Ni<SUP>2+</SUP> was reduced in the Cu<SUP>2+</SUP>[Ni<SUP>2+</SUP>(CN)<SUB>4</SUB>] and confirmed by electron spin resonance (ESR) spectroscopy the Cu<SUP>1+</SUP>[Ni<SUP>2+</SUP>(CN)<SUB>4</SUB>]<SUP>1−</SUP> formation. The concentration variation of Cu<SUP>1+</SUP>[Ni<SUP>2+</SUP>(CN)<SUB>4</SUB>]<SUP>1−</SUP> during CF<SUB>4</SUB> injection demonstrated the degradation of CF<SUB>4</SUB> followed the MER by electrogenerated Cu<SUP>1+</SUP>[Ni<SUP>2+</SUP>(CN)<SUB>4</SUB>]<SUP>1−</SUP>. Maximum removal efficiency of CF<SUB>4</SUB> using electroscrubbing process was 96% at room temperature. Through the variation in gas phase parameters, the gas phase mass transfer coefficient was calculated that can facilitate scale up the developed process. Fourier transform infrared spectroscopy analysis in both the gas and solution phases showed that CH<SUB>3</SUB>CH<SUB>2</SUB>OH was the main product that formed during the removal of CF<SUB>4</SUB> by electrogenerated Cu<SUP>1+</SUP>[Ni<SUP>2+</SUP>(CN)<SUB>4</SUB>]<SUP>1−</SUP> at electroscrubber along with a small amount of CF<SUB>3</SUB>CH<SUB>3</SUB> intermediate. Importantly, this mechanism also avoided formation of the corrosive product HF.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A Cu<SUP>2+</SUP>[Ni<SUP>2+</SUP>(CN)<SUB>4</SUB>] complex was established for carbon tetrachloride degradation to non-corrosive useful product. </LI> <LI> ORP and ESR results demonstrated Cu<SUP>1+</SUP> formation at cathodic half-cell during electrolysis. </LI> <LI> Mass transfer analysis identifies rate limiting behavior and routes to optimization. </LI> <LI> Ethanol found to be a main product in the degradation of CF<SUB>4</SUB> my MER at electro-scrubbing </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P> <B>Synopsis:</B> Ethanol generation was established during the degradation of CF<SUB>4</SUB> by mediated electrocatalytic reduction using electrogenerated Cu<SUP>1+</SUP>[Ni<SUP>2+</SUP>(CN)<SUB>4</SUB>]<SUP>1−</SUP> at electro-scrubbing process.</P> <P>[DISPLAY OMISSION]</P>

Sustainable degradation of carbon tetrafluoride to non-corrosive useful products by incorporating reduced electron mediator within electro-scrubbing

G. Muthuraman,A.G. Ramu,Y. H. Choi,E.J. McAdam,문일식 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.63 No.-

The degradation of CF4 gas using existing technologies produces other types of greenhouse gas (CO2) and corrosive side products. The main aim of this study is to degrade CF4 gas at room temperature into useful products without producing corrosive side products by mediated electrochemical reduction (MER) process using an electrogenerated Cu1+[Ni2+(CN)4]1− mediator. Initial studies on the electrolytic reduction of the hetero-bimetallic complex in catholyte solution at anodized Ti cathode was monitored by oxidation/reduction potential (ORP) variation whether the Cu2+ or Ni2+ was reduced in the Cu2+[Ni2+(CN)4] and confirmed by electron spin resonance (ESR) spectroscopy the Cu1+[Ni2+(CN)4]1− formation. The concentration variation of Cu1+[Ni2+(CN)4]1− during CF4 injection demonstrated the degradation of CF4 followed the MER by electrogenerated Cu1+[Ni2+(CN)4]1−. Maximum removal efficiency of CF4 using electroscrubbing process was 96% at room temperature. Through the variation in gas phase parameters, the gas phase mass transfer coefficient was calculated that can facilitate scale up the developed process. Fourier transform infrared spectroscopy analysis in both the gas and solution phases showed that CH3CH2OH was the main product that formed during the removal of CF4 by electrogenerated Cu1+[Ni2+(CN)4]1− at electroscrubber along with a small amount of CF3CH3 intermediate. Importantly, this mechanism also avoided formation of the corrosive product HF.

Reciprocal influences of dissolved organic matter and nanosized zero-valent iron in aqueous media

Kim, Cheolyong,Chin, Yu-Ping,Ahn, Jun-Young,Wei-Haas, Maya,McAdams, Brandon,Hwang, Inseong Elsevier 2018 CHEMOSPHERE - Vol.193 No.-

<P><B>Abstract</B></P> <P>We investigated concurrent effects between nano-sized zero-valent iron (NZVI) and dissolved organic matter (DOM). Specific UV absorbance of DOM revealed that aromatic/hydrophobic moieties of DOM were bounded to NZVI surfaces. The DOM fluorescence emission peak shifted toward lower wavelength after NZVI exposure, which indicated removal of aromatic DOM fractions. This blue shift of the emission peak also attributes to the reduction of electron acceptors through NZVI-DOM charge transfer complexes. High molecular weight (10<SUP>3</SUP>–10<SUP>4</SUP> Da) DOM fractions, which are suspected to be both aromatic and hydrophobic, were removed. X-ray absorption spectroscopy (XAS) elucidated that Fe(0) content in the 30-d aged NZVI in the presence of DOM (61.6%) was substantially higher than that in the absence of DOM (25.0%). Corrosion and oxidation of NZVI were mitigated due to interruption of electron transfer by surface bounded DOM and stabilization of Fe(II) by Fe-DOM complexes. The XAS also revealed that the evolution of the iron (oxyhydr)oxide shell of NZVI was significantly altered by complexed aromatic DOM.</P> <P><B>Highlights</B></P> <P> <UL> <LI> NZVI surface preferentially sorbs aromatic/high molecular weight moieties of DOM. </LI> <LI> DOM sorption mitigates rapid oxidation of NZVI by water. </LI> <LI> DOM sorption significantly alters the evolution of NZVI shell structure. </LI> <LI> Fe(0) core of NZVI reduces DOM to interrupt intermolecular charge transfer. </LI> <LI> Interactions between NZVI and DOM can substantially affect remediation processes. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>