Improvement of dead-end filtration of biopolymers with pressure electrofiltration

Hofmann, Ralph; Posten, Clemens

doi:10.1016/s0009-2509(03)00271-9

Cited by 57 publications

(23 citation statements)

References 26 publications

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“…Electroosmotic dewatering is an assisted filtration technique that can be used to increase the solid content of suspensions of materials with charged surfaces (Iwata et al 2013;Mahmoud et al 2010). It has proved to be useful in increasing the solid content of cellulosic materials with high specific surface areas (Wetterling et al 2017a), such as microfibrillated cellulose suspensions (Heiskanen et al 2014), and has also shown potential for use in the dewatering of both biopolymers (Gözke and Posten 2010;Hofmann et al 2006;Hofmann and Posten 2003) and hydrogels (Tanaka et al 2014). Using electroosmotic dewatering prior to drying can decrease the total energy demand of the dewatering operation (Larue et al 2006;Loginov et al 2013;Mahmoud et al 2011) and is therefore also attracting significant research interest in the treatment of wastewater sludge (Citeau et al 2012;Mahmoud et al 2011;Olivier et al 2015).…”

Section: Introductionmentioning

confidence: 99%

Electroosmotic dewatering of cellulose nanocrystals

et al. 2018

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One of the main challenges for industrial production of cellulose nanocrystals is the high energy demand during the dewatering of dilute aqueous suspensions. It is addressed in this study by utilising electroosmotic dewatering to increase the solid content of suspensions of cellulose nanocrystals. The solid content was increased from 2.3 up to 15.3 wt%, i.e. removal of more than 85% of all the water present in the system, at a much lower energy demand than that of thermal drying. Increasing the strength of the electric field increased not only the dewatering rate but also the specific energy demand of the dewatering operation: the electric field strength used in potential industrial applications is thus a trade-off between the rate of dewatering and the energy demand. Additionally, it was found that high local current intensity had the potential of degrading cellulose nanocrystals in contact with the anode. The maximum strength of the electric field applied should therefore be limited depending on the equipment design and the suspension conditions.

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Section: Introductionmentioning

confidence: 99%

Electroosmotic dewatering of cellulose nanocrystals

et al. 2018

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“…In most cases, high retention values are only achievable at very high surfactant concentrations, which is associated with a more dramatic drop in filtrate flow rate [8,9]. Since the bottleneck of membrane filtration is the low filtrate flow rate due to fouling, electric field-enhanced filtration has been known for a long time as a more effective way of membrane filtration [12][13][14][15]; however, in practice, it is still not very common because of the four processes of electrophoresis, electroosmosis, electrolysis and viscosity reduction which may have opposite effects during the process [13].…”

Section: Introductionmentioning

confidence: 99%

Dead‐End Liposomal Electro‐Filtration: Phenol Removal by Dioctadecyl Dimethyl Ammonium Chloride as a Case Study

et al. 2010

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Among the important efforts that have been made for the removal of trace organic molecules, sorption by micelles and subsequent membrane filtration is a promising method which, however, still suffers from a number of disadvantages such as low efficiency and high energy consumption. In this article, we present the results of the sorption of phenol (as an important trace organic pollutant in industrial wastewater) to dioctadecyl dimethyl ammonium chloride (DODAC) liposomes, as well as the filtration properties of the resulting dispersion. Whereas the sorption of phenol by a 0.5 wt % DODAC dispersion at neutral pH and ambient temperature was only 26-35 %, it increased to above 95 % at pH 11. Applying an electric field during the filtration process considerably improved both the filtrate flow rate and the retention. An electric field of 5 V/cm increased the filtrate flow rate at 200 kPa 30-fold.

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“…A stainless steel-stainless steel couple of electrodes were chosen for this work. The electrodes were placed downstream of the filter cloths/cake without direct contact with the cloth or cake, in a flowing electrolyte solution that ensures the current to flow between the electrodes and the product (Hofmann and Posten, 2003). In addition, the solution swept away continuously the electrolysis products and the filtrate, and transferred the heat out of the filter chamber.…”

Section: Introductionmentioning

confidence: 99%

Pressure electroosmotic dewatering with continuous removal of electrolysis products

Larue

Wakeman

Tarleton

et al. 2006

Chemical Engineering Science

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Pressurised electroosmotic dewatering (PED) is usually implemented in classical filters with the electrodes making a direct contact with the material or the filter cloths. Thus, electrolysis products generated at the electrodes (gas, ions) tend to accumulate in the solid/liquid mixture being dewatered. This results in a non-uniform distribution of water content, porosity, electric field intensity, and particle zeta potential throughout the mixture, affecting progress of the PED process. This paper proposes a specific design of filter press to study PED in the absence of disturbances from electrolysis products. An experimental study was carried out on a gelatinous bentonite suspension at 8.5% w/w solid. The influence of the ionic conductivity of suspension (2-25 mS/cm), the current intensity (20-300 mA) and the pressure (2.5-15 bar) were investigated. In order to improve the energetic yield of PED, the conductivity and current intensity should be limited, as observed in earlier works. The pressure increase considerably aids the water removal and leads to better product dryness. For PED at 15 bar and 100 mA, the bentonite reached 40% w/w solid for 0.7 kWh/kg of water removed. This study emphasizes that to analyse PED precisely it is important to clarify the dependence of the electroosmotic flow rate on the porosity and pressure.

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Improvement of dead-end filtration of biopolymers with pressure electrofiltration

Cited by 57 publications

References 26 publications

Electroosmotic dewatering of cellulose nanocrystals

Electroosmotic dewatering of cellulose nanocrystals

Dead‐End Liposomal Electro‐Filtration: Phenol Removal by Dioctadecyl Dimethyl Ammonium Chloride as a Case Study

Pressure electroosmotic dewatering with continuous removal of electrolysis products

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