Comparison of lead(II) ions accumulation and bioavailability on the montmorillonite and kaolinite surfaces in the presence of polyacrylamide soil flocculant

Heavy metals, such as Pb(II), Cd(II), Hg(II), do not degrade like organic compounds and remain in soil for a long time. The presence of organic, mineral or polymeric substances (such as polyacrylamides) may contribute to the accumulation and immobilization of toxic metals in poorly absorbable form for living organisms. The main aim of the study was to compare the effectiveness of lead(II) ions immobilization on the layered aluminosilicate surfaces in the anionic polyacrylamide presence. The effectiveness of Pb(II) adsorption was tested depending on metal cation concentration, content of dissociable groups in added flocculant as well as internal structure of clay mineral. The desorption tests of heavy metal ions were performed by the use of water and EDTA (ethylenediaminetetraacetic acid). By means of measurements of suspension stability and aggregate size formed in the studied systems, the flocculating ability of anionic polyacrylamide was checked. The electrokinetic parameters of mineral particles, i.e. surface charge density and electrokinetic potential, without and with individual adsorbates were also determined. It has been shown that the Pb cations adsorbed amount and the effectiveness of their immobilization strongly depends on the polyacrylamide presence in the system and the internal structure of aluminosilicate. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

Heavy metals such as lead(II) can remain in soil for a long time and their toxicity to living organisms can be reduced by immobilization with organic, mineral or polymeric substances. The presence of anionic polyacrylamide and the internal structure of aluminosilicate were found to affect the adsorption efficiency of lead(II) ions.