A novel network montmorillonite composite particle directly separated from water after adsorption pollutants

Montmorillonite (Mt) has good adsorption for organic pollutants and heavy metal ions well, so it is essential for application in wastewater treatment. However, Mt has difficulty being separated from water, which limits its widespread application in wastewater treatment. Based on this problem, polyvinylformal-Mt (PVFM-Mt) composite particles were prepared with Mt, polyvinyl-alcohol (PVA), and formaldehyde serving as raw materials, and their structure, morphology and properties were studied. The results showed that the Mt in PVFM-Mt has a layered structure (d(001) = 1.24 nm -1.84 nm); the PVFM in PVFM-Mt exhibits a mesh-bag structure and the PVFM mesh-bag density increased with increasing formaldehyde dosage; the surface of PVFM-Mt is porous and grooved; the zeta potential of PVFM-Mt (-23.8 mV) is equivalent to that of Mt (-24.5 mV); PVFM-Mt has a swelling property in water; and the particle diameter expansion time is doubled, equivalent to Mt raw materials (2.07). In addition, PVFM-Mt is easily separated from water (omega = 1.68%-2.20%,omega is the loss rate of particles in water) and Mt was difficult to engineer separation (omega = 57.92%-59.60%); and the removal rates of methylene blue (MB) and Pb(II) can reach 99.60% and 99.05%, respectively, significantly better than those obtained with Mt (96.99% and 96.36%). PVFM-Mt adsorbs MB and Pb(II) mainly by the electronegativity of the Mt layer, by coordination with oxygen, aluminum hydroxyl groups or broken bonds, and by coordination with oxygen atoms of the hydroxyl and ether bonds of PVFM. The PVFM in the PVFM-Mt adsorption winding also contributes to the adsorption of MB. This work provides a theoretical and application basis for the extensive application of clay mineral materials in wastewater treatment and large-scale production.

Automated summary

Montmorillonite (Mt) is a significant material for wastewater treatment due to its good adsorption capabilities for organic pollutants and heavy metal ions. However, its difficulty in separating from water limits its application. In this study, polyvinylformal-Mt (PVFM-Mt) composite particles were prepared to overcome this issue. PVFM-Mt exhibited excellent separation performance and higher removal rates compared to Mt, providing a theoretical and practical foundation for the extensive application of clay mineral materials in wastewater treatment and large-scale production.