Abstract

Abstract The objective of the present study is to assess the efficiency of fly ash and fly ash agglomerates to remove arsenic(III) from aqueous solution. The maximum static uptakes were achieved to be 13.5 and 5.7 mgAs(III)/adsorbent for nonagglomerated material and agglomerated one, respectively. Isotherm studies showed good fit with the Langmuir (fly ash) and the Freundlich (fly ash agglomerates) isotherm models. Kinetic studies indicated that the sorption of arsenic on fly ash and its agglomerates follows the pseudo-second-order (PSO) chemisorption model (R2 = 0.999). Thermodynamic parameters revealed an endothermic nature of As(III) adsorption on such adsorbents. The adsorption results confirmed that fly ash and its agglomerates can be used for As(III) removal from aqueous solutions. Fly ash can adsorb more arsenic(III) than agglomerates, which are easier to use, because this material is less dusty and easier to separate from solution.

Highlights

  • Arsenic contamination of land and natural waters has recently become a problem on a global scale

  • Effect of pH According to the literature data, the optimum pH for the arsenic(III) adsorption depends on the selection of sorbent type, e.g. for macrofungus (Inonotus hispidus) biomass is 6.01, iron oxide-coated cement (IOCC) 6.74, hydrous titanium dioxide 4.05, biogenic schwertmannite 7–1013, ArsenXnp resin 5.0–8.5 and carbon-based adsorbents < 721

  • The effect of pH on the adsorption of arsenic(III) onto fly ash and fly ash agglomerates (2.5–5.0 mm) was studied at pH range 5–12 and the results are presented in Figure 1 and Figure 2

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Summary

Introduction

Arsenic contamination of land and natural waters has recently become a problem on a global scale. Arsenic is one of the most toxic trace elements. Present in drinking water, has a significant impact on human health. Arsenic contamination may result from a highly developed industry (mining and metallurgy) and geothermal processes. Origin of natural arsenic increases the amount of this element in water. Over 300 minerals contain arsenic in their structures, for example: arsenopyrite and loellingite. Arsenic occurs mainly in the form of oxides of As(III) as arsenite (H2AsO3–) and As(V) as arsenate (H2AsO4–)[1, 2]. Arsenic(III) is the most toxic and mobile form in the environment. Arsenic compounds may migrate through the soil layer to groundwater, which constitutes a potential threat to human life and health

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