Insights into the facet-dependent adsorption of phenylarsonic acid on hematite nanocrystals. Issue 11 (24th September 2019)

• Record Type: Journal Article
• Authors: Cao, Shiyu; Zhang, Xin; Huang, Xiaopeng; Wan, Shuhao; An, Xuezheng; Jia, Falong; Zhang, Lizhi
• Is Part Of: Environmental science. Volume 6:Issue 11(2019)
• Page Start: 3280
• Page End: 3291
• Publication Date: 2019-09-24
• Subjects: Environmental sciences -- Periodicals; Nanotechnology -- Periodicals; 620.505
• DOI: 10.1039/c9en00879a
• Languages: English
• ISSNs: 2051-8153

Abstract

Abstract : Various methods were used to study the facet-dependent adsorption of PhAs on two model hematite samples: nanocubes with {012} facet and nanoplates with {001} facet. Abstract : Organic arsenics have been frequently detected in natural environments and regarded as a group of emerging contaminants. Elucidating the migration of organic arsenics requires a deep understanding of intrinsic adsorption mechanisms of organic arsenics on iron-bearing minerals, which are seldom investigated. In this study, we investigated the facet-dependent adsorption behavior of phenylarsonic acid (PhAs) on hematite nanocrystals with open circuit potential (OCP) analysis, batch adsorption experiments, adsorption isotherm curves, synchrotron-based As K-edge extended X-ray absorption fine structure (EXAFS) spectroscopy, attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, and density functional theory (DFT) calculations. We found that organic arsenics adsorbed on two facets ( e.g. {001} and {012}) of hematite through the same non-protonated inner-sphere coordination but in different molecular configurations. Surface complexation models were set up to analyze the preferred coordination geometries dependent on the facets, and the {012} facet was found to favor the PhAs adsorption more than the {001} facet. These findings clarified the dependence of organic arsenic adsorption on the hematite facets, and shed light on the environmental effects of hematite on the migration of PhAs.