Interactions of Ag nanoparticles with humic acid present in surface water

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.

Water Disinfection: Unleashing the Power of Bicarbonate Ions in Chitosan–Silver Nanocomposite for Greener and More Efficient Silver Utilization

“…However, in the presence of 2, 2.5, and 5 mg/L humic acid concentrations, 2.4, 1.8, and 1.4 log 10 reductions, respectively, are achieved at the end of 1 h. In these cases, a complete 3 log 10 reduction is achieved at the end of 2 h. The reduction in the disinfection rate can be due to the binding of Ag + with −OH, −COOH, and −CHO functional groups of humic acid and the associated reduction in free Ag + in the solution. 26 It is also reported that the humic acid−Ag + complexes can adsorb on the surface of AgNC, 27 thereby blocking the AgNC pores and reducing the Ag + release. To verify the complexation reaction, the speciation of Ag + in various concentrations of humic acid is simulated using the software Visual Minteq version 3.1 (available free to download at https://vminteq.com/download/).…”

Fractionation and preconcentration of silver nanoparticles at environmentally relevant concentrations through induced eco-corona formation and spICP-MS characterization

“…Humic acid (HA) is a type of dissolved organic matter with a complex organic structure 32 of molecular weight ranging from 2 to 5 kDa. It comprises carboxylic and phenolic functional groups, is well soluble in water at a high pH, and presents a negative charge in pH values between 4 and 10.…”