Arsenic removal from As-hyperaccumulator Pteris vittata biomass: Coupling extraction with precipitation. (February 2018)

• Record Type: Journal Article
• Authors: da Silva, Evandro B.; de Oliveira, Letuzia M.; Wilkie, Ann C.; Liu, Yungen; Ma, Lena Q.
• Is Part Of: Chemosphere. Volume 193(2018)
• Page Start: 288
• Page End: 294
• Publication Date: 2018-02
• Subjects: Arsenic recovery -- Ethanol -- Extraction -- Speciation -- Precipitation -- Magnesium arsenate; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2017.10.116
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: Proper disposal of As-hyperaccumulator Pteris vittata biomass (Chinese brake fern) enhances its application in phytoremediation. The goal of this study was to optimize As removal from P. vittata (PV) biomass by testing different particle sizes, extractants, extraction times and solid-to-liquid ratios. PV biomass was extracted using different extractants followed by different Mg-salts to recover soluble As via precipitation. Water-soluble As in PV biomass varied from 6.8% to 61% of total As depending on extraction time, with 99% of As being arsenate (AsV). Extraction with 2.1% HCl, 2.1% H3 PO4, 1 M NaOH and 50% ethanol recovered 81, 78, 47 and 14% of As from PV biomass. A follow-up extraction using HCl recovered 27–32% with ethanol recovering only 5%. Though ethanol showed the lowest extractable As, residual As in the biomass was also the lowest. Among the extractants, 35% ethanol was the best to remove As from PV biomass. Approximately 90% As was removed from PV biomass using particle size <1 mm at solid:liquid ratio 1:50 and pH 6 for 2 h. Adding MgCl2 at As:Mg ratio of 1:400 with pH 9.5 was effective to precipitate soluble As, resulting in 98% removal. Effective removal of As from PV biomass prior to disposal helps make phytoremediation more feasible. Graphical abstract: Image Highlights: Extraction was coupled with precipitation to remove As from P. vittata biomass. Optimized extraction was based on ethanol/water with particle size <1 mm for 2 h. The method extracted ∼90% As from P. vittata biomass. Magnesium was added to precipitate soluble As from P. vittata to form Mg3 (AsO4 )2 . The optimized precipitation removed ∼98% of soluble As.