Membrane electro-oxidizer: A new hybrid membrane system with electrochemical oxidation for enhanced organics and fouling control

Mameda, Naresh,Park, Hyung-June,Choo, Kwang-Ho Pergamon Press 2017 Water research Vol.126 No.-

<P><B>Abstract</B></P> <P>The synergistic combination of membrane filtration with advanced oxidation is of particular interest for next-generation wastewater treatment technologies. A membrane electro-oxidizer (MEO) hybridizing a submerged microfilter and an electrochemical cell was developed and investigated for tertiary treatment of secondary industrial (textile) wastewater effluent. Laboratory- and pilot-scale MEO systems were designed and evaluated for treatment efficiency and membrane fouling control. The MEO achieved substantial removal of color (50–90%), turbidity (>90%), and bacteria (>4 log) as well as chemical oxygen demand (13–31%) and 1,4-dioxane (∼25–53%). Fluorescence-based parallel factor analysis disclosed the degradation of humic-like organics with fluorophores. Size exclusion chromatograms with organic carbon detection confirmed the removal of specific organic molecules with ∼100 Da. While investigating the effects of oxidant quenching agents, reactive chlorine species and hydrogen peroxide were found to be most responsible for the anodic oxidation of secondary effluent organics. The efficacy of membrane fouling mitigation by the MEO was greater when higher electric current densities were applied, but was not dependent on the number of electrochemical cells installed. The MEO is a promising technology for enhanced organics removal with simultaneous fouling control due to its multifunctional active oxidants.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A membrane electro-oxidizer integrates a membrane and an electrode for advanced treatment. </LI> <LI> Substantive, simultaneous removal of organics and particles is achieved in a single reactor. </LI> <LI> Reactive chlorine species and hydrogen peroxide are dominant oxidants in the process. </LI> <LI> Membrane fouling is alleviated due to electrochemically generated oxidants. </LI> <LI> Pilot-scale testing successfully demonstrates the potential of the new hybrid treatment. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Electrochemical filtration process for simultaneous removal of refractory organic and particulate contaminants from wastewater effluents

Mameda, Naresh,Park, Hyeona,Choo, Kwang-Ho Elsevier 2018 Water research Vol.144 No.-

<P><B>Abstract</B></P> <P>Versatile electrochemical reactions are effective for removing a wide range of water contaminants. This study focuses on the development and testing of bifunctional electrocatalytic filter anodes as reactive and separating media for the simultaneous removal of refractory dissolved organic and particulate contaminants from real wastewater effluents. The results show that the TiO<SUB>2</SUB> particle interlayers formed between the Ti fiber support and the top composite metal oxide catalyst layers assist in reducing filter pores to an effective size range that enables removal of most particulates within the wastewater. The double-sheet design, which is a sandwich-structured module with an internal void space for permeate, prevents filter fouling, and transmembrane pressure can be maintained at a very low level of <5 kPa during batch and continuous flow reactor operations. Substantive and simultaneous removal of dissolved organics (e.g., chromophores, fluorophores, 1,4-dioxane, chemical oxygen demand, and total organic carbon) and particulate matter (i.e., turbidity) are achieved, although removal rates and efficacies differ depending on the electric current density applied. Decolorization and particulate rejection occur swiftly and immediately, but 1,4-dioxane degradation is relatively slow and quite time-dependent. Possible 1,4-dioxane degradation pathways during electrocatalysis are also proposed. Electrochemical filtration technology shows considerable promise for use in the next generation of advanced wastewater treatment solutions.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Electrochemical filtration integrates degradation and separation of contaminants. </LI> <LI> Filter pore size is well controlled using TiO<SUB>2</SUB> particles as a filler. </LI> <LI> Double-sheet filter designs are more efficient than single-sheet in fouling control. </LI> <LI> Electrocatalytic filters achieve simultaneous removal of organics and particulates. </LI> <LI> Plausible pathways of electrochemical 1,4-dioxane degradation are proposed. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Treatment of Reverse Osmosis Concentrate by Electrochemical microfiltration

Naresh Mameda,Kwang-Ho Choo 대한환경공학회 2020 대한환경공학회 학술발표논문집 Vol.2020 No.11

막결합형 고도전기산화 시스템을 이용한 산업폐수 고도처리 및 막오염 제어

박형준,Naresh Mameda,추광호,박현아 한국막학회 2017 한국막학회 총회 및 학술발표회 Vol.2017 No.05

산업폐수 처리에서 미량오염물질(독성 유기물, 화합물, 연료 등)의 제거가 중요하다. 생물학적 처리에 의해서는 미량오염물질을 제거하기 어렵다. 따라서 본 연구에서는 분리막과 고도전기산화를 접목하여 색도, 미세입자등을 효과적으로 제거하고 막오염을 저감시키는 막결합형 고도전기산화시스템을 개발하였다. 색도는 원수 120 도(Pt-Co 색도 값)에서 처리수 20 도이하로 제거되었고, 탁도의 경우 처리수 0.1 NTU이하의 수준으로 감소하였다. 또한 막오염 저감의 성능으로 전극을 켜지않고 실험하였을때 16 kPa까지 증가하였으며 0.5 A/L전류를 공급하였을 때 5 kPa으로 유지되었다. 본 연구는 한국환경산업기술원의 환경융합 신기술 개발사업(No. 2015001640004) 연구결과의 일부이다.

전기활성 복합산화물 나노와이어 분리막의 개발 및 생물반응기 적용

박현아,Naresh Mameda,Syed Salman Ali Shah,추광호 한국막학회 2022 한국막학회 총회 및 학술발표회 Vol.2022 No.11

Catalytic metal oxide nanopowder composite Ti mesh for electrochemical oxidation of 1,4-dioxane and dyes

Park, Hyeona,Mameda, Naresh,Choo, Kwang-Ho Elsevier 2018 Chemical Engineering Journal Vol.345 No.-

<P><B>Abstract</B></P> <P>Electrocatalytic degradation of micropollutants is an attractive strategy for advanced wastewater management, but the development and optimization of innovative anodic materials are needed. This study investigated newly designed metal-TiO<SUB>2</SUB> nanopowder composite coated Ti mesh anodes for enhanced degradation of 1,4-dioxane (10 mg/L spiked) and dyes present in real industrial wastewater effluents. Based on multi-component mixture coating tests, a metal-TiO<SUB>2</SUB> composite for the most efficient electrocatalytic degradation of 1,4-dioxane was attained in the binary molar composition range of Ru:Ti = 0.6:0.4–0.9:0.1. Interestingly, Ir addition (i.e., ternary metal oxide composite) always had an antagonistic impact on the electrocatalytic performance. The binary metal oxide composite structure was X-rayed and identified as comprising RuO<SUB>2</SUB>-TiO<SUB>2</SUB> crystals. Substantive removal of 1,4-dioxane and color was achieved with a small coating amount, but thicker coating had no or negative effects. This is possibly because the production of the oxidants responsible for organics degradation (reactive chlorine species and hydrogen peroxide) decreases with excessive coating layers. A properly coated binary RuO<SUB>2</SUB>-TiO<SUB>2</SUB> composite Ti mesh anode was as effective (or more so) than the boron-doped diamond electrode in terms of 1,4-dioxane degradation and decolorization of real textile wastewater.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Metal oxide composite Ti mesh anodes for efficient 1,4-dioxane removal were designed. </LI> <LI> The most active metal oxide structure (RuO<SUB>2</SUB>-TiO<SUB>2</SUB>) and composition were identified. </LI> <LI> The 0.6RuO<SUB>2</SUB>-0.4TiO<SUB>2</SUB> composite anode outperformed a boron-doped diamond electrode. </LI> <LI> Forming a proper coating layer thickness is required for optimal 1,4-dioxane removal. </LI> <LI> Reactive chlorine species and H<SUB>2</SUB>O<SUB>2</SUB> oxidants are predominant at the composite anode. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Mixed metal oxide coated polymer beads for enhanced phosphorus removal from membrane bioreactor effluents

Park, Hak-Soon,Kwak, Se-Hoon,Mahardika, Dedy,Mameda, Naresh,Choo, Kwang-Ho Elsevier 2017 CHEMICAL ENGINEERING JOURNAL -LAUSANNE- Vol.319 No.-

<P><B>Abstract</B></P> <P>Membrane bioreactors are effective and attractive for wastewater reclamation and reuse, but phosphorus polishing is required to meet more stringent environmental regulations. Mixed metal oxide coated beads composed of Fe-Ti bimetal oxides on a sulfonated polymer were fabricated, characterized, and tested for phosphorus removal from membrane bioreactor effluents. Ti doping substantially enhanced the adsorption rate and capacity of the coated beads, possibly due to more positively charged surfaces. The mixed metal oxide coated beads were highly selective to phosphate ions (selectivity factor >25) against background ions (e.g., Cl<SUP>−</SUP>, NO<SUB>3</SUB> <SUP>−</SUP>, and SO<SUB>4</SUB> <SUP>2−</SUP>), although they were less selective against bicarbonate and organics. Regenerated beads showed greater adsorption performance than the virgin ones. Ca binding to mixed metal oxide layers was responsible for enhanced phosphorus sorption, presumably resulting from the formation of calcium phosphate. The phosphorus recovery from the exhausted column adsorber was successful with alkaline solution (e.g., >90% P was recovered at a NaOH load of 0.2eq/L bed. Using mixed metal oxide chemically anchored on polymer beads for phosphorus sorption would be a promising complement to biological phosphorus removal.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Fe-Ti bimetal oxide-coated composite beads were investigated for phosphorus removal. </LI> <LI> A small amount of Ti dopant enhanced phosphorus removal significantly. </LI> <LI> Phosphate selectivity was remarkable against common background anions. </LI> <LI> Ca binding to the coated bead improved phosphate sorption. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>