Mass Transfer Characteristics during the Removal of Dissolved Heavy Metals from Waste Solutions in Gas Sparged Fluidized Beds of Ion Exchange Resins

Zarraa, Mahmoud A.

doi:10.1002/(sici)1521-4125(199906)22:6<533::aid-ceat533>3.0.co;2-h

Cited by 4 publications

(2 citation statements)

References 23 publications

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“…Regarding the ion exchange and reverse osmosis process, for example, the main disadvantage of the ion exchange process is the secondary chemical waste resulting from the regeneration of the saturated resin by acid. In the conventional reverse osmosis system, significant energy is needed to drive the water through the membrane, and the membrane will also undergo degradation with time , .…”

Section: Introductionmentioning

confidence: 99%

Novel Graphene-Like Electrodes for Capacitive Deionization

Zou

Pan

et al. 2010

Environ. Sci. Technol.

414

226

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Capacitive deionization (CDI) is a novel technology that has been developed for removal of charged ionic species from salty water, such as salt ions. The basic concept of CDI, as well as electrosorption, is to force charged ions toward oppositely polarized electrodes through imposing a direct electric field to form a strong electrical double layer and hold the ions. Once the electric field disappears, the ions are instantly released back to the bulk solution. CDI is an alternative low-energy consumption desalination technology. Graphene-like nanoﬂakes (GNFs) with relatively high specific surface area have been prepared and used as electrodes for capacitive deionization. The GNFs were synthesized by a modified Hummers' method using hydrazine for reduction. They were characterized by atomic force microscopy, N2 adsorption at 77 K and electrochemical workstation. It was found that the ratio of nitric acid and sulfuric acid plays a vital role in determining the specific surface area of GNFs. Its electrosorption performance was much better than commercial activated carbon (AC), suggesting a great potential in capacitive deionisation application. Further, the electrosorptive performance of GNFs electrodes with different bias potentials, flow rates and ionic strengths were measured and the electrosorption isotherm and kinetics were investigated. The results showed that GNFs prepared by this process had the specific surface area of 222.01 m²/g. The specific electrosorptive capacity of the GNFs was 23.18 µmol/g for sodium ions (Na+) when the initial concentration was at 25 mg/L, which was higher than that of previously reported data using graphene and AC under the same experimental condition. In addition, the equilibrium electrosorption capacity was determined as 73.47 µmol/g at 2.0 V by fitting data through the Langmuir isotherm, and the rate constant was found to be 1.01 min⁻¹ by fitting data through pseudo first-order adsorption. The results suggested that the chemically synthesized GNFs can be used as effective electrode materials in CDI process for brackish water desalination.

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Section: Introductionmentioning

confidence: 99%

Novel Graphene-Like Electrodes for Capacitive Deionization

Zou

Pan

et al. 2010

Environ. Sci. Technol.

414

226

View full text Add to dashboard Cite

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“…[3][4][5][6][7][8][9][10]. Precipitation is known to be effective for the treatment of wastewater with a high concentration of iron, but the large amount of sludge produced after treatment may cause side effects.…”

Section: Introductionmentioning

confidence: 99%