Effective Removal of Boron from Aqueous Solutions by Inorganic Adsorbents: A Review

Abstract

Increasing levels of boron in water exceeding acceptable thresholds have triggered concerns regarding environmental pollution and adverse health effects. In response, significant efforts are being made to develop new adsorbents for the removal of boron from contaminated water. Among the various materials proposed, inorganic adsorbents have emerged as promising materials due to their chemical, thermal, and mechanical stability. This review aims to comprehensively examine recent advances made in the development of inorganic adsorbents for the efficient removal of boron from water. Firstly, the adsorption performance of the most used adsorbents, such as magnesium, iron, aluminum, and individual and mixed oxides, are summarized. Subsequently, diverse functionalization methods aimed at enhancing boron adsorption capacity and selectivity are carefully analyzed. Lastly, challenges and future perspectives in this field are highlighted to guide the development of innovative high-performance adsorbents and adsorption systems, ultimately leading to a reduction in boron pollution.

Keywords: adsorption; boron; inorganic adsorbents; metal (hydr)oxides; surface modification.

Figure 1

Distribution of borate species in solution as a function of pH, depicted for concentrations of 216 mg/L (a) and 270 mg/L (b).

Figure 2

Example of the binding mechanism of boron with any glycol compound used as adsorbent. Adapted with permission from Ref. [83]. Copyright 2022, copyright Elsevier Ltd.

Figure 3

A schematic illustration of preparation steps for functionalizing γ-Fe₂O₃-silica particles with NMDG. Adapted with permission from Ref. [91]. Copyright 2010 copyright John Wiley and Sons.

Figure 4

Synthesis pathway of organosiloxane Si-NMDG. Adapted with permission from Ref. [93]. Copyright 2016, copyright Wiley-VCH Verlag GmbH & Co. KGaA.