Arsenic(V) removal in wetland filters treating drinking water with different substrates and plants

Min Wu, Qingyun Li, Xianqiang Tang, Zhuo Huang, Li Lin, Miklas Scholz

Research output: Contribution to journalArticlepeer-review

15 Citations (Scopus)

Abstract

Constructed wetlands are an attractive choice for removing arsenic (As) within water resources used for drinking water production. The role of substrate and vegetation in As removal processes is still poorly understood. In this study, gravel, zeolite (microporous aluminosilicate mineral), ceramsite (lightweight expanded clay aggregate) and manganese sand were tested as prospective substrates while aquatic Juncus effuses (Soft Rush or Common Rush) and terrestrial Pteris vittata L. (Chinese Ladder Brake; known as As hyperaccumulator) were tested as potential wetland plants. Indoor batch adsorption experiments combined with outdoor column experiments were conducted to assess the As removal performances and process mechanisms. Batch adsorption results indicated that manganese sand had the maximum As(V) adsorption rate of 4.55 h-1 and an adsorption capacity of 42.37 μg/g compared to the other three aggregates. The adsorption process followed the pseudo-first-order kinetic model and Freundlich isotherm equations better than other kinetic and isotherm models. Film-diffusion was the rate-limiting step. Mean adsorption energy calculation results indicated that chemical forces, particle diffusion and physical processes dominated As adsorption to manganese sand, zeolite and gravel, respectively. During the whole running period, manganese sand-packed wetland filters were associated with constantly 90% higher As(V) reduction of approximate 500 μg/L influent loads regardless if planted or not. The presence of P. vittata contributed to no more than 13.5% of the total As removal. In contrast, J. effuses was associated with a 24% As removal efficiency.

Original languageEnglish
Pages (from-to)618-638
Number of pages21
JournalInternational Journal of Environmental Analytical Chemistry
Volume94
Issue number6
DOIs
Publication statusPublished - May 2014
Externally publishedYes

Keywords

  • Freundlich isotherm
  • Juncus effuses
  • Pteris vittata
  • adsorption
  • manganese sand

ASJC Scopus subject areas

  • Analytical Chemistry
  • Environmental Chemistry
  • Water Science and Technology
  • Waste Management and Disposal
  • Soil Science
  • Pollution
  • Public Health, Environmental and Occupational Health
  • Health, Toxicology and Mutagenesis

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