Simultaneous removal of atrazine and heavy metal ions using sulfonated polymeric microspheres through an adsorptive filtration process: Insights into the synergistic and competitive adsorption

The combined pollution of surface water caused by organic and inorganic contaminants has become an environmental issue worthy of attention. Adsorption has been acknowledged as a practical and efficient water treatment process. However, the combined interactions between organic and inorganic pollutants on the adsorbents remain ambiguous. In this work, a novel multi-function sulfonated polyacrylate-divinylbenzene (PADVB) microspheres were rapidly and successfully prepared for removing organic pollutants and heavy metals ions from water. The theoretical maximum adsorption capacity of ATZ and Pb(II) by sulfonated PADVB was calculated as 280 mg g⁻¹ and 163 mg g⁻¹, respectively. Additionally, dynamic adsorption based on an adsorptive-filtration reactor combined with in-situ regeneration was equipped, which proved to be effective and practical for the removal of combined pollution of trace contaminants from natural water. The simultaneous adsorption of ATZ and heavy metal ions could be attributed to the combined effects of multiple adsorption mechanisms, such as electrostatic attraction, complexation, Bronsted acid-base interaction, hydrogen bonds, and π-π interactions. Besides, the complexation between ATZ and heavy metal ions was confirmed by batch adsorption experiments and multiple characterization techniques, which play an important role in the synergistic interactions. In the binary adsorption systems, the heavy metal ions acted as a connector between ATZ and the surface of the microspheres through complexation, which could partly offset the competition of adsorptive binding sites. This work provided a promising adsorptive-filtration reactor to recycle and reuse powder adsorbent for solving the trace-level combined pollution in the environmental water and expanded the insights of adsorptive behaviours between organic pollutants and heavy metal ions.