Modeling arsenic removal by co-precipitation under variable redox conditions

M.W. Korevaar, D. Vries, A. Ahmad

Research output: Chapter in Book/Report/Conference proceedingConference paperAcademicpeer-review

Abstract

Drinking water companies in the Netherlands are actively investigating routes to reduce arsenic (As) to <1 µg L−1 in drinking water. Co-precipitation of As with iron during groundwater treatment is a promising method. When As(III) is present in raw water, permanganate (MnO4) can be dosed to oxidize As(III) to As(V) in order to improve As removal efficiency. The dosages of MnO4 and Fe(III) to achieve <1 µg L−1 As in the treatment effluents depend on the composition of raw water. The coprecipitation of As(III) and As(V) with ferrihydrite under variable raw water composition and redox environments, controlled by oxygen (O2) or MnO4 is modeled in this study by the generalized double layer model, and redox equilibrium reactions. Results show that the pH of the treatment process is critical to determine the As removal efficiency. At pH = 8 the highest As removal is obtained, followed by pH = 6 while pH = 7 gives the least removal. HCO3, PO4 and H4 SO4 hamper the adsorption of As(V). In future work, the model outcome will be assessed by experiments. Furthermore, the model will be extended with oxidation kinetics in case oxidation (by e.g. oxygen) occurs at a slower rate than the (mean) residence time of the water in the process.

Original languageEnglish
Title of host publicationEnvironmental Arsenic in a ChangingWorld - 7th International Congress and Exhibition Arsenic in the Environment, 2018
EditorsYong-Guan Zhu, Huaming Guo, Prosun Bhattacharya, Jochen Bundschuh, Arslan Ahmad, Ravi Naidu
PublisherCRC Press/Balkema
Pages432-434
Number of pages3
ISBN (Print)9781138486096
DOIs
Publication statusPublished - 2018
Event7th International Congress and Exhibition Arsenic in the Environment, 2018 - Beijing, China
Duration: 1 Jul 20186 Jul 2018

Publication series

NameEnvironmental Arsenic in a ChangingWorld - 7th International Congress and Exhibition Arsenic in the Environment, 2018

Conference

Conference7th International Congress and Exhibition Arsenic in the Environment, 2018
CountryChina
CityBeijing
Period1/07/186/07/18

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