Anionic polyacrylamide as a substance strengthening the Pb(II) immobilization on the kaolinite surface

Abstract

The main purpose of the study was to examine lead(II) ion immobilization on the kaolinite surface and determine the effect of soil flocculant (macromolecular compound) on this process. For this reason, the adsorption measurements of anionic polyacrylamide and/or Pb(II) ions on the kaolinite surface were performed. Moreover, the impact of heavy metal on electrokinetic and stability properties of kaolinite/polyacrylamide/supporting electrolyte system was determined. It was done based on the results of potentiometric titration, electrophoretic mobility, and absorbance measurements. The most important conclusions of the study were as follows: (1) kaolinite is an effective Pb(II) adsorbent when ion concentration in the environment equals 1 or 10 ppm (it adsorbs 80% and 72% of the ions, respectively), (2) when Pb(II) concentration in the environment is 100 ppm, kaolinite adsorbs only 29% of the ions, and (3) anionic polyacrylamide may strengthen the Pb(II) adsorption on the kaolinite surface (in the presence of 100 ppm AN PAM 30% and 1 ppm Pb(II), even 96% of the ions are adsorbed). Due to the above process, the bioavailability of heavy metal for organisms is considerably limited.

Impact of Sinorhizobium meliloti Exopolysaccharide on Adsorption and Aggregation in the Copper(II) Ions/Supporting Electrolyte/Kaolinite System

“…In addition to electrostatic interactions, Cu(II) adsorption on kaolinite may be connected by other mechanisms, i.e., ion exchange, surface complexation and van der Waals attractions [ 31 ]. The previous study on the adsorption of lead(II) and chromium(VI) ions on kaolinite also indicated the best fitting of adsorption isotherm data to Langmuir model [ 11 , 12 , 32 ].…”

“…Recently, several scientists focused on the impact of polymeric substances, pH and temperature on the adsorption of metal or non-metal ions on clay minerals. For example, Fijałkowska et al [ 11 ] found that lead(II) had a stronger affinity to the kaolinite surface in the presence of anionic polyacrylamide. The same team [ 12 ] observed that cationic polyacrylamide adsorbed on the kaolinite surface contributed to higher adsorption level of chromium(VI) ions.…”

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

“…The Pb(II) adsorbed amount on kaolinite, for the initial Pb(II) concentration 10 ppm, was equal to 0.09 mg/m 2 [51]. Kennedy Oubagaranadin and Murthy [54] calculated the maximum monolayer adsorption capacity of montmorillonite-illite clayit was equal to 52 mg/g.…”

“…In previous study, the impact of anionic polyacrylamide on the Pb(II) immobilization on kaolinite was examined. In that case, the selected polymer enhanced the heavy metal accumulation on the solid [51]. Szewczuk-Karpisz et al [24] found that anionic polyacrylamide favoured Cu(II) adsorption on the hay-based activated biochar.…”

“…Anionic polyacrylamide adsorbed amount on kaolinite, another clay mineral, were also determined. At pH 5 it was equal to 0.32 mg/m 2 for AN PAM 5% and 0.21 mg/m 2 for AN PAM 30% [51]. Goethite and gibbsite were also examined as sorbents of AN PAM containing 40% of carboxylic groups.…”