The Potential for the Treatment of Antimony-Containing Wastewater by Iron-Based Adsorbents
School of Civil Engineering, Hunan University of Science and Technology, Xiangtan 411201, China
Hunan Provincial Key Laboratory of Shale Gas Resource Utilization, Xiangtan 411201, China
School of Science & Sport, University of the West of Scotland, Paisley PA1 2BE, UK
Author to whom correspondence should be addressed.
Water 2017, 9(10), 794; https://doi.org/10.3390/w9100794
Received: 1 September 2017 / Revised: 11 October 2017 / Accepted: 12 October 2017 / Published: 16 October 2017
(This article belongs to the Special Issue Heavy Metals and Potentially Toxic Elements (PTEs) in Water)
Antimony (Sb) and its compounds are considered as global priority pollutants. Elevated concentrations of antimony in natural and industrial process wastewater are of global concern, particularly given interest in the potential toxicity and harm to the environment from aquatic exposure. Iron-based materials for treatment by adsorption are widely regarded to have potential merit for the removal of trace contaminants from water and especially in the search for efficient and low-cost techniques. In this paper, we review the application of iron-based materials in the sorption treatment of antimony contaminated water. The interaction of Sb is discussed in relation to adsorption performance, influencing factors, mechanism, modelling of adsorption (isotherm, kinetic and thermodynamic models), advantages, drawbacks and the recent achievements in the field. Although iron-based adsorbents show promise, the following three aspects are in need of further study. Firstly, a select number of iron based binary metal oxide adsorbents should be further explored as they show superior performance compared to other systems. Secondly, the possibility of redox reactions and conversion between Sb(III) and Sb(V) during the adsorption process is unclear and requires further investigation. Thirdly, in order to achieve optimized control of preferential adsorption sites and functional groups, the mechanism of antimony removal has to be qualitatively and quantitatively resolved by combining the advantages of advanced characterization techniques such as Fourier transform infrared spectroscopy(FTIR), X-ray photoelectron spectroscopy (XPS), Atomic force microscope(AFM), X-ray absorption near edge structure(XANES), and other spectroscopic methods. We provide details on the achievements and limitations of each of these stages and point to the need for further research.