Interactions of Ag nanoparticles with humic acid present in surface water

Abstract

Abstract The present paper reports aggregation behaviour of humic acid (HA) in the presence of silver nanoparticles. Aggregation behaviour has been studied from dynamic light scattering (DLS) measurement, in the presence of silver nanoparticle. Silver nanoparticle has been prepared through chemical route and characterized by plasmon resonance spectroscopy. HA used in the study has been characterized by UV–Vis and fluorescence study; its charged state has been evaluated from the study of its interaction with a cationic dye ruthenium bipyridine. It has been found that HA forms small–medium- and large-sized aggregates in the presence of silver nanoparticle as obtained from DLS diameter. The result has been explained in terms of Langmuir–Hinshelwood adsorption model. It has been proposed that hydrogen bonding and hydrophobic interaction play an important role in the formation of aggregates of HA.

Keywords

• Humic acid
• Silver nanoparticles
• DLS
• Langmuir–Hinshelwood