Polymeric ion exchanger supported ferric oxide nanoparticles as adsorbents for toxic metal ions from aqueous solutions and acid mine drainage

Abstract

Background Acid mine drainage (AMD) is a worldwide industrial pollution of grave concern. AMD pollutes both water sources and the environment at large with dissolved toxic metals which are detrimental to human health. This paper reports on the preparation of polymeric ion exchange resins decorated with hydrated iron oxides and their application for the ecological removal of toxic metals ions from AMD. Methods The hydrated iron oxide particles were incorporated within commercial chelating ion exchange resins using the precipitation method. The synthesised hybrid resins were then characterized using appropriate spectroscopic and solid-state techniques. The metal ion levels were measured using the inductively coupled plasma-optical emission spectrometer (ICP-OES). The optimization of contact time, pH, and adsorbent dosage were conducted to enhance the efficiency of adsorption of toxic metals onto the hybrid organic/inorganic nanosorbents. Kinetics and adsorption isotherms were constructed to study the adsorption mechanisms of the adsorbents. Results The results showed that the dispersed Fe-O is hydrated and amorphous within the hybrid materials. The adsorption kinetics followed the pseudo-second-order shown by the high R 2 values. The hybrid adsorbents were finally tested on environmental AMD samples and were able to remove toxic metals Al, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn at various removal degrees. Conclusion Solution pH played a crucial role in the adsorption of toxic metals on hybrid iron oxide adsorbents. The hybrid TP-260 HFO had higher affinity for toxic metals than other prepared adsorbents thus has a potential for acidic mine water pollution remediation. The adsorbed Al(III) can be recovered using NaCl-NaOH binary solution from the loaded resins.

Recent developments in materials used for the removal of metal ions from acid mine drainage

“…Etale et al (2017) evaluated mesoporous silica nanoparticles and reported that possible configurational advantages of Mn (II) lead to its better adsorption than Cu (II). Similar trends on the influence of pore size were also reported by Nqombolo et al (2019) and Dlamini et al (2019). Table 2 shows the adsorption capacities of some recently studied nano-materials.…”

“…Adsorption is a versatile technique, in the sense that the adsorbent can be restored and subsequently re-used without reducing the removal efficiency (Bai et al 2017). A range of adsorbents for treatment of AMD have been used, which include high density sludge (Sukati et al 2018;Dlamini et al 2019), alkali-barium-calcium (Mulopo and Motaung 2014;Akinwekomi et al 2017), coal fly ash (Rios et al 2008;Madzivire et al 2019) and lignite (Mohan and Chander 2006;Karagüzel et al 2020). Among the studied adsorbents is activated carbon (Hong et al 2017), silica (Etale et al 2016;Lakovleva and Sillanpää 2013) and ferric oxide (Dlamini et al 2019).…”

Mine drainage: Remediation technology and resource recovery

“…Polymeric ion exchange resins impregnated with hydrated iron oxide nanoparticles were prepared and tested as an adsorbent for toxic metals removal from AMD (Dlamini, De Kock, Kefeni, Mamba, & Msagati, 2019). The hybrid nanosorbent exhibited higher affinity for toxic metals from AMD.…”

A novel microbial-plant coupled reactor for remediating acid mine drainage and optimization of carbon sources

“…At present, there are many treatment methods for AMD, including adsorption (Dlamini et al, 2019), membrane ltration (Ricci et al, 2015), advanced oxidation processes (Munyengabe et al, 2020), and chemical reactions (Kefeni et al, 2017). Nevertheless, these methods are extremely resource intensive with high costs or defective in treating AMD with high concentration of ions, which limits their large-scale application (Shi et al, 2019).…”