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Guohua Chen

Bio: Guohua Chen is an academic researcher from Hong Kong Polytechnic University. The author has contributed to research in topics: Anode & Cathode. The author has an hindex of 83, co-authored 407 publications receiving 24131 citations. Previous affiliations of Guohua Chen include South China University of Technology & Chongqing University.


Papers
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TL;DR: In this article, the development, design and applications of electrochemical technologies in water and wastewater treatment are reviewed with particular focus on electrodeposition, electrocoagulation, electroflotation (EF), and electrooxidation.
Abstract: This paper reviews the development, design and applications of electrochemical technologies in water and wastewater treatment. Particular focus was given to electrodeposition, electrocoagulation (EC), electroflotation (EF) and electrooxidation. Over 300 related publications were reviewed with 221 cited or analyzed. Electrodeposition is effective in recover heavy metals from wastewater streams. It is considered as an established technology with possible further development in the improvement of space-time yield. EC has been in use for water production or wastewater treatment. It is finding more applications using either aluminum, iron or the hybrid Al/Fe electrodes. The separation of the flocculated sludge from the treated water can be accomplished by using EF. The EF technology is effective in removing colloidal particles, oil & grease, as well as organic pollutants. It is proven to perform better than either dissolved air flotation, sedimentation, impeller flotation (IF). The newly developed stable and active electrodes for oxygen evolution would definitely boost the adoption of this technology. Electrooxidation is finding its application in wastewater treatment in combination with other technologies. It is effective in degrading the refractory pollutants on the surface of a few electrodes. Titanium-based boron-doped diamond film electrodes (Ti/BDD) show high activity and give reasonable stability. Its industrial application calls for the production of Ti/BDD anode in large size at reasonable cost and durability.

2,577 citations

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TL;DR: Competition from common coexisting ions such as Na+, Ca2+, Mg2+, Cu2+, Ni2+, NO3-, and Cl- was ignorable, which illustrated the selective adsorption of Cr(VI) from wastewater.
Abstract: Hexavalent chromium existing in the effluent is a major concern for the metal-processing plant. In this study, a new method combining nanoparticle adsorption and magnetic separation was developed for the removal and recovery of Cr(VI) from wastewater. The nanoscale maghemite was synthesized, characterized, and evaluated as adsorbents of Cr(VI). Various factors influencing the adsorption of Cr(VI), e.g., pH, temperature, initial concentration, and coexisting common ions were studied. Adsorption reached equilibrium within 15 min and was independent of initial Cr concentration. The maximum adsorption occurred at pH 2.5. The adsorption data were analyzed and fitted well by Freundlich isotherm. Cr(VI) adsorption capacity of maghemite nanoparticles was compared favorably with other adsorbents like activated carbon and clay. Competition from common coexisting ions such as Na+, Ca2+, Mg2+, Cu2+, Ni2+, NO3-, and Cl- was ignorable, which illustrated the selective adsorption of Cr(VI) from wastewater. Regeneration studies verified that the maghemite nanoparticles, which underwent six successive adsorption-desorption processes, still retained the original metal removal capacity. In addition, the adsorption mechanisms were investigated using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopic techniques.

949 citations

Journal ArticleDOI
TL;DR: In this paper, the authors summarized recent research on and development of semiconductor-based photocatalyst materials that are applicable to environmental remediation and/or chemical synthesis purposes, including the incorporation of noble metal nanoclusters onto the surface of semiconducted particles.
Abstract: This feature article summarizes recent research on and development of semiconductor-based photocatalyst materials that are applicable to environmental remediation and/or chemical synthesis purposes. A wide variety of TiO2 particles and/or films have been studied during the past 30 years because they are the most stable and powerful photocatalysts leading to the degradation of various organic pollutants. The photocatalytic performance of other semiconductor materials such as ZnO, SnO2, WO3, Fe2O3 and CdS has also been intensively investigated. A general limitation in the efficiency of any photocatalytic process is the recombination of the photogenerated charge carriers, i.e., of electrons and holes, following bandgap illumination. Considerable efforts have been made to suppress this recombination and hence to enhance the charge carrier separation and the overall efficiency by means of coupling of different semiconductors with desirable matching of their electronic band structures, or incorporation of noble metal nanoclusters onto the surface of semiconductor photocatalyst particles. Modification of the physicochemical properties, such as particle size, surface area, porosity and/or crystallinity of the semiconductor materials, and optimization of the experimental conditions, such as pH, illumination conditions and/or catalyst loading, during photocatalytic reactions have also been carefully addressed to achieve high reaction rates or yields. To utilize solar energy more efficiently, i.e., to extend the optical absorption of the mostly UV-sensitive photocatalysts into the visible light range, numerous research groups have contributed to the development of novel visible light active photocatalysts. With the application of semiconductors with narrower bandgaps such as CdS, Fe2O3 and WO3 being straightforward choices, doping of wide bandgap semiconductors like TiO2 has been the most popular technique to enhance the catalysts' optical absorption abilities. Research on mixed-oxide-based semiconductor photocatalysts with deliberately modulated band structures has also attracted tremendous attention in the past decade, concentrating on, for example, the generation of H2 and/or O2 from H2O splitting, and the degradation of organic pollutants under visible light irradiation. Both theoretical calculations and experimental results have convincingly shown that the developed materials can serve as highly efficient photocatalysts that are both environmentally and economically significant.

869 citations

Journal ArticleDOI
TL;DR: In this paper, the characteristics of restaurant wastewater were investigated and high oil and grease contents were detected, and the optimum charge loading and current density were 1.67-9.95 F/m3 wastewater and 30-80 A/m2 depending on the wastewater tested.
Abstract: The characteristics of restaurant wastewater were investigated. High oil and grease contents were detected. Electrocoagulation was used to treat this type of wastewater. Different electrode materials and operational conditions were examined. Aluminum was preferred to iron. Charge loading was found to be the only variable that affected the treatment efficiency significantly. The optimum charge loading and current density were 1.67–9.95 F/m3 wastewater and 30–80 A/m2 depending on the wastewater tested. The removal efficiency of oil and grease exceeded 94% for all wastewaters tested. The experimental results also show that the electrocoagulation can neutralize wastewater pH. Several mechanisms associated with pH variation are proposed.

807 citations

BookDOI
01 Dec 2010
TL;DR: In this article, the importance of Electrode Material in the Electrochemical Treatment of Wastewater Containing Organic Pollutants for Wastewater Treatment has been discussed, including the use of both anode and cathode reactions in wastewater treatment.
Abstract: Basic Principles of the Electrochemical Mineralization of Organic Pollutants for Wastewater Treatment.- Importance of Electrode Material in the Electrochemical Treatment of Wastewater Containing Organic Pollutants.- Techniques of Electrode Fabrication.- Modeling of Electrochemical Process for the Treatment of Wastewater Containing Organic Pollutants.- Green Electroorganic Synthesis Using BDD Electrodes.- Domestic and Industrial Water Disinfection Using Boron-Doped Diamond Electrodes.- Drinking Water Disinfection by In-line Electrolysis: Product and Inorganic By-Product Formation.- Case Studies in the Electrochemical Treatment of Wastewater Containing Organic Pollutants Using BDD.- The Persulfate Process for the Mediated Oxidation of Organic Pollutants.- Electrocoagulation in Water Treatment.- Electroflotation.- Electroreduction of Halogenated Organic Compounds.- Principles and Applications of Solid Polymer Electrolyte Reactors for Electrochemical Hydrodehalogenation of Organic Pollutants.- Preparation, Analysis and Behaviors of Ti-Based SnO2 Electrode and the Function of Rare-Earth Doping in Aqueous Wastes Treatment.- Wet Electrolytic Oxidation of Organics and Application for Sludge Treatment.- Environmental Photo(electro)catalysis: Fundamental Principles and Applied Catalysts.- Solar Disinfection of Water by TiO2 Photoassisted Processes: Physicochemical, Biological, and Engineering Aspects.- Fabrication of Photoelectrode Materials.- Use of Both Anode and Cathode Reactions in Wastewater Treatment.

463 citations


Cited by
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08 Dec 2001-BMJ
TL;DR: There is, I think, something ethereal about i —the square root of minus one, which seems an odd beast at that time—an intruder hovering on the edge of reality.
Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

33,785 citations

Journal ArticleDOI
TL;DR: It is evident from the literature survey articles that ion-exchange, adsorption and membrane filtration are the most frequently studied for the treatment of heavy metal wastewater.
Abstract: Heavy metal pollution has become one of the most serious environmental problems today. The treatment of heavy metals is of special concern due to their recalcitrance and persistence in the environment. In recent years, various methods for heavy metal removal from wastewater have been extensively studied. This paper reviews the current methods that have been used to treat heavy metal wastewater and evaluates these techniques. These technologies include chemical precipitation, ion-exchange, adsorption, membrane filtration, coagulation-flocculation, flotation and electrochemical methods. About 185 published studies (1988-2010) are reviewed in this paper. It is evident from the literature survey articles that ion-exchange, adsorption and membrane filtration are the most frequently studied for the treatment of heavy metal wastewater.

6,844 citations

Journal ArticleDOI
TL;DR: It is anticipated that this review can stimulate a new research doorway to facilitate the next generation of g-C3N4-based photocatalysts with ameliorated performances by harnessing the outstanding structural, electronic, and optical properties for the development of a sustainable future without environmental detriment.
Abstract: As a fascinating conjugated polymer, graphitic carbon nitride (g-C3N4) has become a new research hotspot and drawn broad interdisciplinary attention as a metal-free and visible-light-responsive photocatalyst in the arena of solar energy conversion and environmental remediation. This is due to its appealing electronic band structure, high physicochemical stability, and “earth-abundant” nature. This critical review summarizes a panorama of the latest progress related to the design and construction of pristine g-C3N4 and g-C3N4-based nanocomposites, including (1) nanoarchitecture design of bare g-C3N4, such as hard and soft templating approaches, supramolecular preorganization assembly, exfoliation, and template-free synthesis routes, (2) functionalization of g-C3N4 at an atomic level (elemental doping) and molecular level (copolymerization), and (3) modification of g-C3N4 with well-matched energy levels of another semiconductor or a metal as a cocatalyst to form heterojunction nanostructures. The constructi...

5,054 citations

Journal ArticleDOI
TL;DR: This paper presents a meta-analyses of the chiral stationary phase transition of Na6(CO3)(SO4)2, Na2SO4, and Na2CO3 of the Na2O/Na2O 2 mixture at the stationary phase and shows clear patterns in the response of these two materials to each other.
Abstract: Jenny Schneider,*,† Masaya Matsuoka,‡ Masato Takeuchi,‡ Jinlong Zhang, Yu Horiuchi,‡ Masakazu Anpo,‡ and Detlef W. Bahnemann*,† †Institut fur Technische Chemie, Leibniz Universitaẗ Hannover, Callinstrasse 3, D-30167 Hannover, Germany ‡Faculty of Engineering, Osaka Prefecture University, 1 Gakuen-cho, Sakai Osaka 599-8531, Japan Key Lab for Advanced Materials and Institute of Fine Chemicals, East China University of Science and Technology, Shanghai 200237, China

4,353 citations

Journal ArticleDOI
TL;DR: In this paper, photo-induced superhydrophilicity was used on the surface of a wide-band gap semiconductor like titanium dioxide (TiO 2 ) for photocatalytic activity towards environmentally hazardous compounds.
Abstract: The utilization of solar irradiation to supply energy or to initiate chemical reactions is already an established idea If a wide-band gap semiconductor like titanium dioxide (TiO 2 ) is irradiated with light, excited electron–hole pairs result that can be applied in solar cells to generate electricity or in chemical processes to create or degrade specific compounds Recently, a new process used on the surface of TiO 2 films, namely, photoinduced superhydrophilicity, is described All three appearances of the photoreactivity of TiO 2 are discussed in detail in this review, but the main focus is on the photocatalytic activity towards environmentally hazardous compounds (organic, inorganic, and biological materials), which are found in wastewater or in air Besides information on the mechanistical aspects and applications of these kinds of reactions, a description of the attempts and possibilities to improve the reactivity is also provided This paper would like to assist the reader in getting an overview of this exciting, but also complicated, field

4,241 citations