Polyaluminum chloride with high Al30 content as removal agent for arsenic-contaminated well water

Mertens, Jasmin; Casentini, Barbara; Armand, Michel; Pöthig, Rosemarie; Wehrli, Bernhard; Furrer, Gerhard

doi:10.1016/j.watres.2011.10.031

Cited by 75 publications

(51 citation statements)

References 31 publications

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“…It is known that PACl contains aluminum monomers and oligomers, as well as Al 13 and Al 30 nanoclusters, with the larger Al 30 nanoclusters having a diameter of 1 nm and a length of 2 nm (Mertens et al, 2012). It has been found, however, that the components of PACl self-aggregate and go on to form larger clusters (Swetland et al, 2013).…”

Section: Discussionmentioning

confidence: 99%

A Hydrodynamic and Surface Coverage Model Capable of Predicting Settled Effluent Turbidity Subsequent to Hydraulic Flocculation

Pennock

Weber-ShirkMonroe

LionLeonard

2018

Environmental Engineering Science

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A widely applicable hydraulic flocculator design model would facilitate increased adoption of this sustainable technology. To this end, the authors previously proposed rate equations for the removal of nonsettleable aggregates in hydraulic flocculators (Pennock et al.). This work continues the prior effort by developing two models for coupled flocculation/sedimentation performance. The first model describes settled effluent turbidity for flocculators where the relative velocities between particles are dominated by viscous forces (e.g., laminar flows). Similarly, the second model applies where inertial forces dominate. Predictions of these models were compared with laboratory-scale flocculation/ sedimentation data obtained from both a laminar-and a turbulent-flow flocculator. The viscous equation fit data from the laminar flow flocculator well. For the turbulent flocculator, both models gave good fits of the data, but the inertial model performed slightly better. The similarity of the two models under the experimental constraints explains this result, and further study in different conditions is needed to delineate the applicability of the models in turbulent flocculation. Given the similarity between the models and that the product of the mean fluid velocity gradient applicable to laminar flow (G) and hydraulic residence time (h), Gh, has historically been used in flocculator design, it is recommended that the viscous flocculation model introduced in this article be used. The new flocculation models have a single adjustable parameter and, in addition to being able to predict settled effluent turbidity from coagulant dose, also provide reasonable estimates of flocculator design parameters from first principles and dimensional analysis.

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Section: Discussionmentioning

confidence: 99%

A Hydrodynamic and Surface Coverage Model Capable of Predicting Settled Effluent Turbidity Subsequent to Hydraulic Flocculation

Pennock

Weber-ShirkMonroe

LionLeonard

2018

Environmental Engineering Science

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“…However, composite coagulants based on aluminum (i.e., PFASiC 1.5-15, PSiFAC 1.5-10, etc.) were not efficient enough for the removal of As(V), in comparison with the composite coagulants based on iron, despite the fact that poly-aluminum chloride has been shown in the literature to be very efficient towards As(V) removal [13]. Therefore, this study was further focused on the use of pre-polymerized coagulants of iron and the specific investigation on As(III) removal.…”

Section: As(v) Removal By Pre-polymerized Coagulants Of Iron and Alummentioning

confidence: 99%

Use of Novel Composite Coagulants for Arsenic Removal from Waters—Experimental Insight for the Application of Polyferric Sulfate (PFS)

et al. 2017

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Abstract:In the present study, several pre-polymerized coagulants of iron and aluminum were tested for their efficiency towards As(V) and As(III) removal from water sources. The results showed that the pre-polymerized coagulants of iron, such as poly-ferric sulfate and poly-ferric silicate chloride, were very efficient for As(V) removal. With regard to As(III) removal, among all examined coagulants, including the conventional ferric chloride, only the poly-ferric sulfate (PFS) was able to reduce As(III) to concentrations below the drinking water regulation limit of 10 µg/L. In contrast, all tested composite coagulants based on aluminum were not capable of removing efficiently both species of arsenic. PFS addition in water containing 4 mM of alkalinity and 25 µg/L of As(V) and As(III) (i.e., total arsenic concentration 50 µg/L) resulted in finished water with less than 5 µg/L arsenic, only by dosing 5 mg Fe-PFS/L at pH 7, whereas, simultaneously, the residual iron concentration was found well below its drinking water regulation limit of 200 µg/L. The use of PFS could provide a viable alternative for As(III) and As(V) removal at household treatment level for application in vulnerable communities, without the need of any additional treatment, such as oxidation of As(III) to As(V).

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“…[3,4] Adding to the interest in the reactivity of these aqueous aluminium nanoparticles is the fact that both Al 13 and Al 30 species have been shown to be effective and cost-efficient sorbents for use in water remediation strategies. [10,11] The fundamental, geochemical and applied interest in the reactivity of Al 30 motivates molecular-level studies of its adsorption processes, though currently there are few such examples in the literature. [12] Recently, we contributed computational studies using density functional theory (DFT) to a collaborative study aimed at characterising and rationalising the adsorption of Cu 2þ onto Al 30 .…”

Section: Introductionmentioning

confidence: 99%

Establishing trends in ion adsorption on the aqueous aluminium hydroxide nanoparticle Al₃₀

Corum

Mason

2014

Molecular Simulation

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The fact that chemical reactions at environmental interfaces are becoming accessible to quantum mechanical computational studies provides geochemical researchers with a new means to predict properties that cannot readily be measured and to develop molecular-level understanding of geochemical model systems. Recent computational studies of Cu 2þ and SO 22 4 adsorption onto the Keggin-based aqueous aluminium nanoparticle (Al 30 O 8 ðOHÞ 56 ðH 2 OÞ 18þ 26 ), or Al 30 , revealed opposing trends in adsorption site preference as a function of molecule surface topology. Specifically, the adsorption site favourable for the inner-sphere adsorption of Cu 2þ is on the caps of Al 30 while outer-sphere SO 22 4prefers adsorption in the so-called beltway region of the molecule. When co-adsorbed, it is predicted that both species adsorb in the beltway, consistent with an experimental crystal structure. Here, we discuss results for individual cation and anion adsorption to Al 30 . Our goals are to better understand how the adsorbate properties govern interactions with Al 30 and to assess whether generalisations can be formed. We test the reactivity of cations (Cu 2þ , Pb 2þ , Zn 2þ ) and anions (SO 22 4 , Cl 2 ) to aqueous Al 30 by using density functional theory modelling. It is determined that all the cations favour the adsorption sites on the caps of Al 30 and both anions favour outer-sphere adsorption in the beltway region. The results are discussed in terms of the electrostatic potential of Al 30 and three-dimensional induced charge density mapping.

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Polyaluminum chloride with high Al30 content as removal agent for arsenic-contaminated well water

Cited by 75 publications

References 31 publications

A Hydrodynamic and Surface Coverage Model Capable of Predicting Settled Effluent Turbidity Subsequent to Hydraulic Flocculation

A Hydrodynamic and Surface Coverage Model Capable of Predicting Settled Effluent Turbidity Subsequent to Hydraulic Flocculation

Use of Novel Composite Coagulants for Arsenic Removal from Waters—Experimental Insight for the Application of Polyferric Sulfate (PFS)

Establishing trends in ion adsorption on the aqueous aluminium hydroxide nanoparticle Al₃₀

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Polyaluminum chloride with high Al30 content as removal agent for arsenic-contaminated well water

Cited by 75 publications

References 31 publications

A Hydrodynamic and Surface Coverage Model Capable of Predicting Settled Effluent Turbidity Subsequent to Hydraulic Flocculation

A Hydrodynamic and Surface Coverage Model Capable of Predicting Settled Effluent Turbidity Subsequent to Hydraulic Flocculation

Use of Novel Composite Coagulants for Arsenic Removal from Waters—Experimental Insight for the Application of Polyferric Sulfate (PFS)

Establishing trends in ion adsorption on the aqueous aluminium hydroxide nanoparticle Al30

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Establishing trends in ion adsorption on the aqueous aluminium hydroxide nanoparticle Al₃₀