Removal of Pb2+ from Aqueous Solutions Using K-Type Zeolite Synthesized from Coal Fly Ash

Yuhei Kobayashi,Takehiro Nakamura,Fumihiko Ogata,Naohito Kawasaki,Chalermpong Saenjum

doi:10.3390/w12092375

Abstract

In this study, a novel zeolite (K-type zeolite) was synthesized from coal fly ash (FA), and adsorption capacity on Pb2+ was assessed. Six types of zeolite (FA1, FA3, FA6, FA12, FA24, and FA48) were prepared, and their physicochemical properties, such as surface functional groups, cation exchange capacity, pHpzc, specific surface area, and pore volume, were evaluated. The quantity of Pb2+ adsorbed by the prepared zeolites followed the order FA < FA1 < FA3 < FA6 < FA12 < FA24 < FA48. Current results indicate that the level of Pb2+ adsorbed was strongly related to the surface characteristics of the adsorbent. Additionally, the correlation coefficient between the amounts of Pb2+ adsorbed and K+ released from FA48 was 0.958. Thus, ion exchange with K+ in the interlayer of FA48 is critical for the removal of Pb2+ from aqueous media. The new binding energies of Pb(4f) at 135 and 140 eV were detected after adsorption. Moreover, FA48 showed selectivity for Pb2+ adsorption in binary solution systems containing cations. The results revealed that FA48 could be useful for removing Pb2+ from aqueous media.

Highlights

In recent years, issues faced by the aquatic environment, such as water wastage (Goal 6)and the presence of plastic bags in the ocean (Goal 14), have become major concerns for sustainable societal development [1]
Exceeded thatunder of other cations under our conditions. These results indicate that the adsorption capacity of FA48 wasofinfluenced by cationicby experimental conditions
Ion exchange with K+ in the interlayer of FA48 is strongly related to the adsorption capacity

Summary

Introduction

Issues faced by the aquatic environment, such as water wastage (Goal 6)and the presence of plastic bags in the ocean (Goal 14), have become major concerns for sustainable societal development [1]. Issues faced by the aquatic environment, such as water wastage (Goal 6). Several heavy metals have been contaminating the aquatic environment through human activities, which are non-biodegradable and accumulate in the ecosystem via the food chain, causing various health problems and diseases [2]. Among these heavy metals, lead (Pb2+ ), mercury (Hg2+ ), and cadmium (Cd2+ ) have been defined as the “big three” harmful heavy metals posing the greatest threat to humans, animals, and the environment [3,4].

Objectives

Methods

Discussion

Conclusion