Stability and interaction of biochar and iron mineral nanoparticles: effect of pH, ionic strength, and dissolved organic matter

Abstract Biochar nanoparticles (BCNPs) and iron mineral (IMNPs), such as ferrihydrite (FHNPs), magnetite (MTNPs), goethite (GTNPs), are often combined used in soil remediation. However, the stability interaction of under various environmental conditions have not been investigated previously. In this study, settling experiments, a semi-empirical model, Derjaguin–Landau–Verwey–Overbeek (DLVO) theory, scanning electron microscopy (SEM) observations, quantum chemical calculations were to study heteroaggregation BCNPs IMNPs. Settling BCNPs-FHNPs BCNPs-GTNPs was stable at neutral alkaline pH (relative concentration unsettled C res’ = 0.679–0.824), whereas fast BCNPs-IMNPs observed acidic (C 0.104–0.628). By contrast, BCNPs-MTNPs consistently showed moderate regardless mass all 0.423–0.673). Both humic acid (HA, 10 mg L ?1 ) ionic strength (IS, 100 mM) facilitated systems, sensitive only IS. Fulvic (10 had general stabilizing effect on systems. The results SEM suggested that between FHNPs (-2755.58 kJ mol stronger than GTNPs (?1706.23 or MTNPs (?1676.73 ). enhancement IMNPs unfavorable (acidic pH, HA, IS) regulated by interaction. Therefore, greater BCNPs-MTNPs. system, high elongated structure may contribute greatly with small interactions. Our highlight influence IS, HA These will be helpful application for Graphical