Effects of humic acid on enhanced removal of lead ions by polystyrene-supported nano-Fe (0) nanocomposite.

ABSTRACT: Polymer-supported nanozero-valent iron composites (D001-nZVI) were fabricated for the removal of lead ions from aqueous solutions by embedding nZVI into the porous polystyrene anion exchanger D001. Humic acid (HA) was selected as a model species because of its ubiquitous existence to gain insight into the influencing factors in the actual application process. The iron contents of the composites were approximately 11.2%, and the smallest ZVI particle size was?~?5 nm. The experimental results showed that the effect of HA on the reduction of lead ions by D001-nZVI was a concentration-dependent process. At low HA concentrations, the surface-competitive adsorption of HA and Pb²⁺ dominated; therefore, the removal efficiency of Pb²⁺ by D001-nZVI decreased from 97.5 to 90.2% with an increasing HA concentration. When the HA concentration increased to 30 mg/L or more, the lead ions removal remained constant with the following possible cooperation mechanism: the competitive adsorption of HA and Pb²⁺ on the nZVI surface and the well-dispersed particles were caused by electrostatic interactions between the HA coating and the nZVI surface. In addition, the adsorption complexation between HA and Pb²⁺ also had a positive effect on the removal of Pb²⁺ at higher concentrations of HA.

SUBMITTER: Wang L 

PROVIDER: S-EPMC7665180 | biostudies-literature | 2020 Nov

REPOSITORIES: biostudies-literature