Enhancing sustainability of household water filters by mixing metallic iron with porous materials

Noubactep, Chicgoua; Caré, Sabine

doi:10.1016/j.cej.2010.06.012

Cited by 49 publications

(46 citation statements)

References 54 publications

(41 reference statements)

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“…Thus, there is diversity among operational factors that can impact the efficiency of a Fe 0 filter. This high degree of diversity for significant factors suggests that only a well-designed systematic approach could identify conditions for optimal operation [40,[73][74][75][76][77].…”

Section: Fe 0 Filtersmentioning

confidence: 99%

“…Here, iron oxides are progressively generated in the system [102,[116][117][118][119], making the efficiency of a Fe 0 filter highly dependent on its physical design (e.g., Fe 0 reactivity, filter bed length, flow velocity). As a sinuous and tortuous material with, therefore, significant intrinsic porosity (available voids which can be used to accommodate the expansive Fe 0 corrosion products), steel wool (SW) can be considered a suitable candidate for use as a filter material [73][74][75]90,120,121]. Several processes take place during Fe 0 filter operation: (i) in-situ generation of Fe corrosion products; (ii) adsorption of dissolved species onto strained solids and all available surfaces, including Fe 0 and its (hydr)oxides; and (iii) biologically induced processes such as biofouling [35,66,69,94,95,109].…”

Section: The State-of-the Artmentioning

confidence: 99%

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Technologies for Decentralized Fluoride Removal: Testing Metallic Iron-based Filters

Ndé-Tchoupé

Crane

Mwakabona

et al. 2015

Water

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Since the realization in the 1930s that elevated fluoride concentrations in drinking water can have detrimental effects on human health, new methods have been progressively developed in order to reduce fluoride to acceptable levels. In the developing world the necessity for filtration media that are both low-cost and sourced from locally available materials has resulted in the widespread use of bone char. Since the early 1990s metallic iron (Fe 0 ) has received widespread use as both an adsorbent and a reducing agent for the removal of a wide range of contaminant species from water. The ion-selectivity of Fe 0 is dictated by the positively charged surface of iron (hydr)oxides at circumneutral pH. This suggests that Fe 0 could potentially be applied as suitable filter media for the negatively charged fluoride ion. This communication seeks to demonstrate from a theoretical basis and using empirical data from the literature the suitability of Fe 0 filters for fluoride removal. The work concludes that Fe 0 -bearing materials, such as steel wool, hold good promise as low-cost, readily available and highly effective decentralized fluoride treatment materials.

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Section: Fe 0 Filtersmentioning

confidence: 99%

Section: The State-of-the Artmentioning

confidence: 99%

Technologies for Decentralized Fluoride Removal: Testing Metallic Iron-based Filters

Ndé-Tchoupé

Crane

Mwakabona

et al. 2015

Water

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“…The situation is exacerbated in rural areas of the developing world where the inputs of nitrogen to agricultural soils are increasing and no centralized drinking water system is available. Therefore efficient and affordable methods for safe drinking water production should be available, both at household and at small and big community level (Noubactep and Caré;Shannon et al, 2008;Sobsey et al, 2008).…”

Section: Silviamentioning

confidence: 99%

Reduction of Nitrate and Ammonium Adsorption Using Microscale Iron Particles and Zeolitite

Comba

Martín

Marchisio

et al. 2011

Water Air Soil Pollut

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“…The latter effect (less initial Fe 0 ) could not improve Fe 0 efficiency in term of Fe 0 reactivity but is known as tool to delay or avoid porosity loss [39][40][41]. of the filter system, but not the second.…”

Section: Metallic Iron For Household Filtersmentioning

confidence: 99%

“…In consequence, two opposite effects may be observed: (i) the porous structure of the CIM induces a larger reactive surface compared to non-porous Fe 0 particle (or compact Fe 0 ); the internal porosity could be regarded as magazine for in-situ generated iron corrosion products and (ii) less initial Fe 0 is used compared to compact Fe 0 particle. The former effect (larger reactive surface) is well-documented as tool to improve Fe 0 efficiency and is the rationale for using nano-scale Fe 0 for water treatment [38].The latter effect (less initial Fe 0 ) could not improve Fe 0 efficiency in term of Fe 0 reactivity but is known as tool to delay or avoid porosity loss [39][40][41]. of the filter system, but not the second.…”

mentioning

confidence: 99%

Dimensioning metallic iron beds for efficient contaminant removal

Noubactep¹,

Caré

2010

Chemical Engineering Journal

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Remediation of contaminated groundwater is an expensive and lengthy process. (ii) used Fe 0 amounts must represent 30 to 60 vol-% of the mixture, and (iii) Fe 0 beds are deep-bed filtration systems. The major output of this study is that thicker barriers are needed for long service life. Fe 0 filters for save drinking water production should use several filters in series to achieve the treatment goal. In all cases proper material selection is an essential issue. [5][6][7][8], and (ii) as reagents to assist biofiltration in household filters [3,9,10]. The fundamental process responsible for contaminant removal in both contexts is necessarily the oxidative dissolution of Fe 0 (iron corrosion) which may be coupled with contaminant reduction (reactive walls) or the subsequent precipitation of iron hydroxides which may be coupled with contaminant adsorption and co-precipitation (household filters).Adsorption, co-precipitation and chemical transformations (oxidation and/or reduction) are not mutually exclusive [11][12][13]. It is obvious that in household filters and reactive walls, a synergy between these three processes is responsible for expected and observed decontamination. Moreover, these processes proceed in the inter-granular porosity of the packed beds which are made up of Fe 0 (100 %) or a mixture of Fe 0 and an inert material (e.g. gravel, pumice, sand) [2,14]. Because of the volumetric expansive nature of the process of iron corrosion [15], the porosity of the filtrating systems certainly decreases with increasing service life, possibly yielding complete permeability loss system (filter clogging) [16,17]. The filling of the pore volume by corrosion products is necessarily coupled with improved size exclusion capacity. Therefore, a fourth mechanism for decontamination in packed Fe 0 beds is The concept that contaminants are fundamentally removed by adsorption and co-precipitation is consistent with many experimental observations which remained non-elucidated by the reductive transformation concept [11,12]. Although researchers are continuing to maintain the validity of the latter concept [24][25][26], the new concept was validated [27,28] and has been independently verified [29,30]. As a matter of course the concept of adsorption/co- Metallic iron for household filtersWhile using slow sand filtration for water treatment in rural Bangladesh, it was observed that the filter efficiency for arsenic removal depends on the iron content of natural waters. Arsenic was readily removed from Fe-rich natural waters. Accordingly, Fe 0 is used "to provide a constant input of iron (soluble or surface precipitate) for groundwater low in soluble iron"[32]. The very efficient resulting filter for As removal was the 3-Kolsi filter [10,33]. A typical 3-Kolsi filter contained a layer of about 3 kg Fe 0 (100 % Fe 0 ). However, the 3-Kolsi filter was not sustainable as it clogged after some 8 weeks of operation [3,34].The remarkable efficiency of 3-Kolsi filters has prompted researchers to further develop the system fo...

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Enhancing sustainability of household water filters by mixing metallic iron with porous materials

Cited by 49 publications

References 54 publications

Technologies for Decentralized Fluoride Removal: Testing Metallic Iron-based Filters

Technologies for Decentralized Fluoride Removal: Testing Metallic Iron-based Filters

Reduction of Nitrate and Ammonium Adsorption Using Microscale Iron Particles and Zeolitite

Dimensioning metallic iron beds for efficient contaminant removal

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