An energy-efficient air-breathing cathode electrocoagulation approach for the treatment of arsenite in aquatic systems

Maitlo, Hubdar Ali,Lee, Jechan,Park, Joo Yang,Kim, Jo-Chun,Kim, Ki-Hyun,Kim, Jung Hwan THE KOREAN SOCIETY OF INDUSTRIAL AND ENGINEERING 2019 JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY -S Vol.73 No.-

<P><B>Abstract</B></P> <P>An air-breathing cathode electrocoagulation (ACEC) process with a sacrificial aluminum anode was used to treat arsenite (As(III)) from aqueous systems. Its performance was investigated by controlling operational parameters. As(III) removal efficiency of the ACEC increased from 81 to 86% with an increase in NaCl concentration from 10 to 20mM. Furthermore, we were able to observe the oxidation of As(III) into its corresponding ions as well as the production of an aluminum oxide hydroxide in the form of boehmite. This study describes ACEC as one of the most energy-efficient treatment methods for As(III) removal based on its performance evaluation.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

An energy-efficient air-breathing cathode electrocoagulation approach for the treatment of arsenite in aquatic systems

Hubdar Ali Maitlo,이제찬,박주양,김조천,김기현,김정환 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.73 No.-

An air-breathing cathode electrocoagulation (ACEC) process with a sacrificial aluminum anode was usedto treat arsenite (As(III)) from aqueous systems. Its performance was investigated by controllingoperational parameters. As(III) removal efficiency of the ACEC increased from 81 to 86% with an increasein NaCl concentration from 10 to 20 mM. Furthermore, we were able to observe the oxidation of As(III)into its corresponding ions as well as the production of an aluminum oxide hydroxide in the form ofboehmite. This study describes ACEC as one of the most energy-efficient treatment methods for As(III)removal based on its performance evaluation.

Effects of supporting electrolytes in treatment of arsenate-containing wastewater with power generation by aluminumair fuel cell electrocoagulation

Hubdar Ali Maitlo,김정환,안병민,박주양 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.57 No.-

Aluminum–air fuel cell electrocoagulation was evaluated for arsenate removal during power production. Effects of operational parameters (type and concentration of individual and mixed supporting electrolytes and initial pH) were investigated. 1 mg L−1 arsenate in 1 L of anolyte (with 10 mM NaCl) was reduced to 1 μg L−1 in 4 h, power density produced was 112 mW/m2. 8 mM Na2SO4 mixed with 10 mM NaCl created optimal conditions as mixed supporting electrolyte. Power density increased to 308 mW/m2 and arsenate was reduced to 15 μg L−1 after 24 h. This indicates aluminum–air fuel cell electrocoagulation is useful treatment process.

Removal mechanism for chromium (VI) in groundwater with cost-effective iron-air fuel cell electrocoagulation

Ali Maitlo, Hubdar,Kim, Ki-Hyun,Yang Park, Joo,Hwan Kim, Jung Elsevier 2019 Separation and purification technology Vol.213 No.-

<P><B>Abstract</B></P> <P>Metal-air fuel cell electrocoagulation is one of the most cost-effective and innovative treatment options for metals in water. Here, the removal mechanism of chromium (Cr(VI)) was assessed using an iron-air fuel cell electrocoagulation (IAFCEC) system. Simultaneously, the effects of such treatment were also investigated with respect to a list of parameters controlling groundwater quality. During the IAFCEC operation, in-situ production of stable iron hydroxides (e.g., maghemite, hematite, and goethite) was experienced due to the sacrificial oxidation of the iron anode electrode. Therefore, these iron hydroxides were responsible for direct co-precipitation of aqueous Cr(VI). The removal efficiency of the system was assessed by varying the initial concentrations of Cr(VI) such as1, 5, and 10 mg L<SUP>−1</SUP>). The IAFCEC, when operated with low concentrations of competing anions (e.g., silicate, phosphate, magnesium, and calcium), was capable of treating 6 L of water containing 1 mg L<SUP>−1</SUP> Cr(VI) per day with an operating cost of 0.2 USD m<SUP>−3</SUP>. This study demonstrates the IAFCEC as one of the most cost-effective treatment methods for Cr(VI) removal based on evaluation of performance relative to other options commonly available.</P> <P><B>Highlights</B></P> <P> <UL> <LI> IAFCEC is most cost-effective for Cr(VI) treatment and power generation. </LI> <LI> In-situ produced iron hydroxides were used for direct co-precipitation of Cr(VI). </LI> <LI> IAFCEC can obtain 100% Cr(VI) removal within 4 h with operating cost of 0.2 USD m<SUP>3</SUP>. </LI> <LI> Merits of system are evident as it is less dependent upon operating parameters. </LI> </UL> </P>

Effects of supporting electrolytes in treatment of arsenate-containing wastewater with power generation by aluminumair fuel cell electrocoagulation

Maitlo, Hubdar Ali,Kim, Jung Hwan,An, Byung Min,Park, Joo Yang THE KOREAN SOCIETY OF INDUSTRIAL AND ENGINEERING 2018 JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY -S Vol.57 No.-

<P><B>Abstract</B></P> <P>Aluminum–air fuel cell electrocoagulation was evaluated for arsenate removal during power production. Effects of operational parameters (type and concentration of individual and mixed supporting electrolytes and initial pH) were investigated. 1mgL<SUP>−1</SUP> arsenate in 1L of anolyte (with 10mM NaCl) was reduced to 1μgL<SUP>−1</SUP> in 4h, power density produced was 112mW/m<SUP>2</SUP>. 8mM Na<SUB>2</SUB>SO<SUB>4</SUB> mixed with 10mM NaCl created optimal conditions as mixed supporting electrolyte. Power density increased to 308mW/m<SUP>2</SUP> and arsenate was reduced to 15μgL<SUP>−1</SUP> after 24h. This indicates aluminum–air fuel cell electrocoagulation is useful treatment process.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The aluminum–air fuel cell electrocoagulation was used to treat arsenate. </LI> <LI> The 10mM NaCl was an effective anode electrolyte. </LI> <LI> The 1mgL<SUP>−1</SUP> arsenate from 1L of wastewater was reduced to 1μgL<SUP>−1</SUP> in 4h. </LI> <LI> The maximum power density was 112mW/m<SUP>2</SUP> with 10mM NaCl anolyte. </LI> <LI> The maximum power density was 308mW/m<SUP>2</SUP> with 8:10mM of mixed Na<SUB>2</SUB>SO<SUB>4</SUB>:NaCl anolyte. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Arsenic treatment and power generation with a dual-chambered fuel cell with anionic and cationic membranes using NaHCO₃ anolyte and HCl or NaCl catholyte

Maitlo, Hubdar Ali,Kim, Jung Hwan,Park, Joo Yang Elsevier 2017 CHEMOSPHERE - Vol.172 No.-

<P><B>Abstract</B></P> <P>Dual-chambered fuel cells with an iron anode and an air-carbon cathode separated by an ion exchange membranes have been used to treat arsenate during power production. To select an effective catholyte, the dual-chambered fuel cell consisted 90 mL of 0.1 M HCl or 0.5 M NaCl as the catholyte and 1 L of 0.1 M NaHCO<SUB>3</SUB> as the anolyte at an initial pH 5. The 0.1 M HCl was an effective catholyte, with which 1 ppm arsenate in 1 L of anolyte was reduced to 5 ppb in 1 h, and the maximum power density was about 6.3 w/m<SUP>2</SUP> with an anion exchange membrane fuel cell (AEM_FC) and 4.4 w/m<SUP>2</SUP> with a cation exchange membrane fuel cell (CEM_FC). Therefore, 90 mL of 0.1 M HCl was used as a catholyte to treat 20 L of 0.1 M NaHCO<SUB>3</SUB> anolyte containing 1 ppm arsenate at an initial pH of 5 or 7. The arsenate level at pH 5 decreased to less than 5 ppb in 4 h, and the maximum power density was 5.9 W/m<SUP>2</SUP> and 4.7 W/m<SUP>2</SUP> with AEM_FC and CEM_FC, respectively. When using 0.01 M NaHCO<SUB>3</SUB> as the anolyte at pH 5, arsenate was reduced to less than 5 ppb in 8 and 24 h for AEC_FC and CEM_FC, respectively. However, when using an anolyte at pH 7, arsenate could not be effectively removed in 24 h. Therefore, when using carbonate as an anolyte, the solution should be adjusted to a weakly acidic pH in order to remove arsenate.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The iron-air dual-chambered fuel cell with AEM and CEM was used to treat arsenate. </LI> <LI> The 0.1 M HCl was an effective cathode electrolyte. </LI> <LI> The 1 ppm arsenate form 20 L of wastewater was reduced to less than 5 ppb in 4 h. </LI> <LI> The maximum power density was 5.9 W/m<SUP>2</SUP> and 4.7 W/m<SUP>2</SUP> with AEC_FC and CEM_FC. </LI> <LI> The iron-air dual-chambered fuel cell has possibility of real-world applications. </LI> </UL> </P>

Arsenic Treatment and Power Generation with Double Chambered Fuel Cell

알리후브다르 ( Hubdar Ali Maitlo ),김정환 ( Jung-hwan Kim ),박주양 ( Joo-yang Park ) 한국물환경학회(구 한국수질보전학회) 2015 한국물환경학회·대한상하수도학회 공동 춘계학술발표회 Vol.2015 No.-

Treatment of synthetic arsenate wastewater with iron-air fuel cell electrocoagulation to supply drinking water and electricity in remote areas

Kim, Jung Hwan,Maitlo, Hubdar Ali,Park, Joo Yang Elsevier 2017 Water research Vol.115 No.-

<P><B>Abstract</B></P> <P>Electrocoagulation with an iron-air fuel cell is an innovative arsenate removal system that can operate without an external electricity supply. Thus, this technology is advantageous for treating wastewater in remote regions where it is difficult to supply electricity. In this study, the possibility of real applications of this system for arsenate treatment with electricity production was verified through electrolyte effect investigations using a small-scale fuel cell and performance testing of a liter-scale fuel cell stack. The electrolyte species studied were NaCl, Na<SUB>2</SUB>SO<SUB>4</SUB>, and NaHCO<SUB>3</SUB>. NaCl was overall the most effective electrolyte for arsenate treatment, although Na<SUB>2</SUB>SO<SUB>4</SUB> produced the greatest electrical current and power density. In addition, although the current density and power density were proportional to the concentrations of NaCl and Na<SUB>2</SUB>SO<SUB>4</SUB>, the use of concentrations above 20 mM of NaCl and Na<SUB>2</SUB>SO<SUB>4</SUB> inhibited arsenate treatment due to competition effects between anions and arsenate in adsorption onto the iron hydroxide. The dominant iron hydroxide produced at the iron anode was found to be lepidocrocite by means of Raman spectroscopy. A liter-scale four-stack iron-air fuel cell with 10 mM NaCl electrolyte was found to be able to treat about 300 L of 1 ppm arsenate solution to below 10 ppb during 1 day, based on its 60-min treatment capacity, as well as produce the maximum power density of 250 mW/m<SUP>2</SUP>.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Arsenate treatment with production of electricity using iron-air fuel cell. </LI> <LI> NaCl was optimal electrolyte for arsenate treatment with electricity production. </LI> <LI> Stack iron-air fuel cell with 10 mM NaCl electrolyte could treat 1 ppm arsenate. </LI> <LI> Stack iron-air fuel cell with 10 mM NaCl electrolyte produced 250 mW/m<SUP>2</SUP> electricity. </LI> <LI> System may be suitable for supplying drinking water and electricity in remote areas. </LI> </UL> </P>

The potential of biochar as sorptive media for removal of hazardous benzene in air

Khan, Azmatullah,Szulejko, Jan E.,Samaddar, Pallabi,Kim, Ki-Hyun,Liu, Botao,Maitlo, Hubdar Ali,Yang, Xiao,Ok, Yong Sik Elsevier 2019 Chemical Engineering Journal Vol. No.

<P><B>Abstract</B></P> <P>Airborne benzene is hazardous even at sub-ppm levels. Therefore, an effective strategy is required for its removal, such as the use of a sorbent with large adsorption capacity or high breakthrough volume. To meet the goal, the performance for the removal of benzene was assessed by loading benzene at 5 Pa inlet partial pressure against seven types of biowaste-derived biochar: (1) paper mill sludge, (2) conventional biochar with magnetic properties, (3) biochar composites with carbon nanotubes (CNTs), (4) gasification biochar from mixed feedstock, (5) gasification biochar from a single feedstock, (6) modified gasification biochar, and (7) activated carbon (AC) as a reference. The 298 K maximum adsorption capacities (mg g<SUP>−1</SUP>), when measured at a benzene inlet pressure of 5 Pa (or 50 ppm in ultrapure nitrogen) and flow rate of 50 mL atm min<SUP>−1</SUP>, varied widely for different biochars, from 0.35 (MS: Swine manure + plastic mulch film waste) to 144 mg g<SUP>−1</SUP> (XC-1: biochar from mixed feedstock); their 10% breakthrough volumes (BTV) were in the range of 0.22–492 L g<SUP>−1</SUP>, respectively. The experimental data (capacity vs. benzene outlet partial pressure) could be fitted to either two or three linearized Langmuir isotherms with distinctive sorption mechanisms ((1) a retrograde region (Type III isotherm: 0 to ∼0.2 Pa), (2) an intermediate pressure region (0.2 and 2.0 Pa), and (3) a higher pressure region (>2 Pa)) which was also confirmed similarly by Freundlich, Dubinin–Radushkevich, and Elovich fitting. About 65% of the maximum capacity was achieved in the retrograde region. The strongest biochar sorbent, XC-1, showed similar performance as activated carbon to prove its feasibility toward air quality management (AQM) applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Performance of biochars for gaseous benzene removal was assessed. </LI> <LI> The adsorption isotherms were assessed by maximum capacity, partition coefficient, and BTV. </LI> <LI> Retrograde was found for activated carbon and gasified/modified biochars. </LI> <LI> The strong sorbents of multiple sorption sites fitted best with Elovich and Langmuir models. </LI> </UL> </P>

Treatment of ethanolamine using an Fe(III)‐based, two‐chamber microbial fuel cell with continuous Fe(II) oxidation at the air cathode

Seo, Seok‐,Ju,Shin, Ja‐,Won,Maitlo, Hubdar Ali,Park, Joo‐,Yang WILEY & SONS 2016 Journal of Chemical Technology & Biotechnology Vol.91 No.5

<P>BACKGROUNDThe objective of this study was to investigate the feasibility of developing an integrated bio-electrochemical system for the removal of ethanolamine from wastewater by combining an Fe(III)-based microbial fuel cell (MFC) with a continuous Fe(II) oxidation system for simultaneous oxidation and reduction of iron in the same compartment. The ethanolamine in the Fe(III)-based MFC can be effectively converted to electrical energy by using the catalytic activity of microorganisms. In this respect, the authors investigated whether the introduction of a system for Fe(III) regeneration could enhance the sustainability of both power generation and the removal of ethanolamine in this integrated system. RESULTSThe experimental results obtained with a traditional Fe(III)-based MFC, operated with a ferric sulfate solution of 25 or 50 mmol L-1 Fe(III) mixed with ethylenediaminetetraacetic acid (EDTA) solution of 10 mmol L-1, showed that increasing the Fe(III) concentration leads to improved performance of the MFC; the maximum power density, open circle voltage (OCV), and Coulombic efficiency (CE) were all improved. However, the effluents from the cathode chamber contained a low concentration of Fe(III) due to deficient regeneration of Fe(III). In the integrated bio-electrochemical system developed in this work (enhanced Fe(III)-based MFC), the generated Fe(II) was oxidized at the air cathode via favorable oxygen diffusion and a Fe(II)-based fuel cell (FC). CONCLUSIONElectricity was sustainably generated from the enhanced MFC with 25 mmol L-1 Fe(III); the highest performance, in terms of maximum power density, OCV and CE, was achieved using 50 mmol L-1 Fe(III), thus indicating the increased efficiency of this integrated system. (c) 2015 Society of Chemical Industry</P>