Removal of Different Kinds of Heavy Metals by Novel PPG-nZVI Beads and Their Application in Simulated Stormwater Infiltration Facility

Xiaoran Zhang,Lei Yan,Junfeng Liu,Ziyang Zhang,Chaohong Tan

doi:10.3390/app9204213

Abstract

Polyvinyl alcohol and pumice synthetized guar gum-nanoscale zerovalent iron beads (PPG-nZVI beads) were synthesized, and their adsorption towards Pb2+, Cu2+, and Zn2+ ions was evaluated. The adsorption kinetics of metal ions was well fitted by the pseudo-second-order model. The adsorption rate decreased followed in the order of Cu2+ > Pb2+ > Zn2+, consistent with the reduction potential of the ions. The sorption isotherm was well fitted by Langmuir model. The maximum adsorption capacity decreased followed in the order of Pb2+ > Cu2+ > Zn2+, which suggested that the strength of covalent bonds between the metal ions and surface functional groups substituted to the beads is one of the major factors in the adsorption process. Adsorption increased with the increase of pH and the largest sorption occurred at pH 5.5, while ionic strength did not significantly influence the adsorption process. The application of PPG-nZVI beads as filling materials in the simulated stormwater infiltration facility shows good removal efficiency in treating the contaminated water containing Pb2+, Cu2+, Zn2+, Cr6+, and Cd2+ and the removal rate was more than 65% at least. The results indicated that the PPG-nZVI beads could be applied as promising sorbents for purification of heavy metal contaminated water.

Highlights

Heavy metals with density more than 5.0 g/cm3 [1] bring significant impacts on the environment and human
We further examined the removal efficiency of PPG-nZVI beads towards different kind of heavy metal ions as well as the influence of pH and ionic strength on their removal
The results indicated that the different heavy metal ions by beads strongly pH-dependent

Summary

Introduction

Heavy metals with density more than 5.0 g/cm3 [1] bring significant impacts on the environment and human. Heavy metals prefer to accumulate in organisms and much of them are known to be carcinogenic and highly toxic [2]. They have attracted great attention due to their potential hazards to ecosystems and human health. Varieties of methods such as chemical precipitation, reverse osmosis, electrochemical treatment, ion exchange, membrane filtration, and adsorption have been used to remove heavy metals from wastewater [3]. Adsorption is found to be one of the promising techniques with advantages such as high efficiency, environmental friendly, and low operational and maintenance costs

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Results

Conclusion