Arsenic removal by Japanese oak wood biochar in aqueous solutions and well water: Investigating arsenic fate using integrated spectroscopic and microscopic techniques

Nabeel Khan Niazi, Irshad Bibi, Muhammad Shahid, Yong Sik Ok, Sabry M. Shaheen, Jörg Rinklebe, Hailong Wang, Behzad Murtaza, Ejazul Islam, M. Farrakh Nawaz, Andreas Lüttge

Research output: Contribution to journalArticle

64 Citations (Scopus)

Abstract

In this study, we examined the sorption of arsenite (As(III)) and arsenate (As(V)) to Japanese oak wood-derived biochar (OW-BC) in aqueous solutions, and determined its efficiency to remove As from As-contaminated well water. Results revealed that, among the four sorption isotherm models, Langmuir model showed the best fit to describe As(III) and As(V) sorption on OW-BC, with slightly greater sorption affinity for As(V) compared to As(III) (QL = 3.89 and 3.16 mg g− 1; R2 = 0.91 and 0.85, respectively). Sorption edge experiments indicated that the maximum As removal was 81% and 84% for As(III)- and As(V)-OW-BC systems at pH 7 and 6, respectively, which decreased above these pH values (76–69% and 80–58%). Surface functional groups, notably –OH, –COOH, –C–O, –CH3, were involved in As sequestration by OW-BC, suggesting the surface complexation/precipitation and/or electrostatic interaction of As on OW-BC surface. Arsenic K-edge X-ray absorption near edge structure (XANES) spectroscopy indicated that 36% of the added As(III) was partially oxidized to As(V) in the As(III) sorption experiment, and in As(V) sorption experiment, 48% of As(V) was, albeit incompletely, reduced to As(III) on OW-BC surface. Application of OW-BC to As-contaminated well water (As: 27–144 μg L− 1; n = 10) displayed that 92 to 100% of As was depleted despite in the presence of co-occurring competing anions (e.g., SO4 2 −, CO3 2 −, PO4 3 −). This study shows that OW-BC has a great potential to remove As from solution and drinking (well) water. Overall, the combination of macroscopic sorption data and integrated spectroscopic and microscopic techniques highlight that the fate of As on biochar involves complex redox transformation and association with surface functional moieties in aquatic systems, thereby providing crucial information required for implication of biochar in environmental remediation programs.

Original languageEnglish
Pages (from-to)1642-1651
Number of pages10
JournalScience of the Total Environment
Volume621
DOIs
Publication statusPublished - 2018 Apr 15

Keywords

  • Arsenic contamination
  • Drinking water, FTIR, remediation
  • SEM-EDX
  • Sorbent
  • Toxicity, XANES

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution

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