Anionic polyacrylamide influence on the lead(II) ion accumulation in soil – the study on montmorillonite

Abstract

Purpose Polymeric substances, as soil conditioners, limit the erosion process as well as improve the soil structure. The same macromolecular compounds may influence the heavy metal accumulation in soil environment. The main aim of this study was investigation of anionic polyacrylamide (AN PAM) effect on the lead(II) ion sorption on the montmorillonite surface. The effects of Pb(II) ion concentration, sequence of heavy metal and anionic polymer addition into the system as well as anionic group content in the PAM macromolecules were also studied. Materials and methods The study was performed on montmorillonite (clay mineral). Two types of polymers were used: AN PAM 5% and AN PAM 30% containing 5% and 30% of carboxylic groups, respectively. The adsorbed amounts of Pb(II) ions or AN PAM on the solid were determined spectrophotometrically. Electrokinetic properties of the examined systems were established using potentiometric titration and microelectrophoresis method. The montmorillonite aggregation without and with selected substances was described based on the sedimentation study. Results At pH 5 the Pb(II) adsorbed amount on montmorillonite equaled 0.05 mg/m 2 (for the initial concentration 10 ppm). Anionic polyacrylamide increased this value significantly (it was 0.11 mg/m 2 with AN PAM 5% and 0.11 mg/m 2 with AN PAM 30%). The lead(II) ions presence causes a slight increase of the anionic PAM adsorption on the montmorillonite surface. For example, for the initial polymer concentration 100 ppm, the AN PAM 5% adsorbed amount without Pb(II) equaled 0.49 mg/m 2 , whereas with Pb(II)-0.57 mg/m 2. What is more, anionic polyacrylamide and lead(II) ions affected electrokinetic properties and stability of the montmorillonite suspension. Conclusions Anionic polyacrylamide makes the Pb(II) accumulation on the montmorillonite surface larger and, as a consequence, reduces the Pb(II) availability to organisms. Therefore, this macromolecular compound can certainly be used to remediate soils contaminated with heavy metals.

Simultaneous Removal of Pb2+ and Zn2+ Heavy Metals Using Fly Ash Na-X Zeolite and Its Carbon Na-X(C) Composite

“…Simple ion adsorption affects usually the surface charge of adsorbents. It was described, inter alia, by Fijałkowska et al [ 41 , 53 , 54 , 55 ]. In their studies, Pb 2+ ions caused an increase in the negative values of σ 0 of two clay minerals, kaolinite and montmorillonite.…”

Accumulation of toxic Pb(II) ions by the iron-containing minerals in the presence of ionic polyacrylamide soil conditioner

“…These complexes can have inter- and intramolecular structure, due to the divalent character of lead cations. Their formation causes noticeable increase of adsorbed amounts of heavy metal ions, which bind to multiple dissociated carboxyl groups within one or two polymeric chains, thereby increasing the level of adsorption of anionic polyacrylamide (for AN PAM, adsorbed amount reaches value 75.2 mg/g and for Pb(II) — 78.3 mg/g) (Fijałkowska et al 2020a , b ). Such mechanism can lead to the formation of adsorption multilayers.…”

“…Soil particles in the soil–water phase bind better with each other, so that soil erosion does not occur (Ben-Hur and Keren 1997 ; Green et al 2004 ). The action of polyacrylamide is beneficial not only from the point of view of agrotechnical operations but also has an important ecological aspect, because the greater amounts of pesticides, fertilizers, heavy metals, and other harmful substances are retained in the cultivated soil and does not move in the environment (Wiśniewska et al 2015 ; He et al 2019 ; Fijałkowska et al 2020a , b ; 2021 ).…”

An Overview on Composite Sorbents Based on Polyelectrolytes Used in Advanced Wastewater Treatment

“…The core-shell architecture could be achieved by direct deposition of different types of natural/synthetic polyelectrolytes (CS, PEI, humic acid, PAH, PVAm, PAA, PSS etc.) on 2D-cores, such as GO [21][22][23]25,115,116] and Ti 3 C 2 -MXenes [117], or 3D-cores, including Fe 3 O 4 [57,108,122,123,126,127], SiO 2 [24,28,83,90,100,101,103,109], SiO 2 /Fe 3 O 4 [88,128], PS [91], FeS [129], clays [99,111,112], CaCO 3 [102], mesoporous diatomite [89], natural fibers [107] and sand [123]. The direct deposition of the organic or organic/inorganic "shell" onto inorganic or organic "core" could be carried out in (i) one-step, by physisorption [21,89,108,111,112], grafting [23,83,88,100,115,117], ionic or solvent gelation/precipitation [25,27,…”