Removal of lead from aqueous solutions using three biosorbents of aquatic origin with the emphasis on the affective factors

Maryam Rezaei,Ali Mashinchian Moradi,Nima Pourang

doi:10.1038/s41598-021-04744-0

Abstract

The biosorptive potentials of three aquatics-based biosorbents, including shells of a bivalve mollusk and scales of two fish species for Pb removal from aqueous solutions were evaluated, for the first time. A Box–Behnken design with the response surface methodology was used to investigate the effects of the seven important variables (contact time, temperature, initial concentration, dosage, size, salinity and pH) on the sorption capacity of the sorbents. Among the seven studied factors, the effects of biosorbent dosage, initial concentration and pH were significant for all the response variables, while biosorbent size was not significant for any of the responses. The initial concentration was the most influential factor. The presence of Pb ions on the surfaces of the biosorbents after the adsorption was clearly confirmed by the SEM–EDX and XRF analyses. The maximum sorption capacities of the biosorbents were comparable to the literature and the descending order was as follows: scales of Rutilus kutum and Oncorhynchus mykiss and the shells of Cerastoderma glaucum. The isotherm studies revealed Langmuir model applicability for the Pb adsorption by R. kutum and O. mykiss scales, while Freundlich model was fitted to the adsorption C. glaucum shells.

Highlights

The biosorptive potentials of three aquatics-based biosorbents, including shells of a bivalve mollusk and scales of two fish species for Pb removal from aqueous solutions were evaluated, for the first time
It was found that the initial concentration was the most influential factor, which had positive effect on adsorption capacity of the three biosorbents
The considerable effects of initial concentration on adsorption efficiency of various biosorbents for heavy metals have been reported by some other researchers (e.g. Osu and Odoemelam[69]; Zayadi and Othman[4]; Dileepa Chathuranga et al.[11]; Ayodele and Adekola[39]; Al-Saeedi et al.36)

Summary

Introduction

The biosorptive potentials of three aquatics-based biosorbents, including shells of a bivalve mollusk and scales of two fish species for Pb removal from aqueous solutions were evaluated, for the first time. Pollution of aquatic ecosystems caused by heavy metals has been one of the major environmental threats over the last several decades and is of high ecological significance. These concerns are arise from their non-biodegradability, high toxicity and huge discharge into the e nvironment[1]. Heavy metals occur naturally in aquatic ecosystems, but with large variations in concentration They enter the environment from various man-made sources. These metals are released into the aquatic environments through direct discharges into both freshwater and marine ecosystems or through indirect r outes[2, 3] These hazardous pollutants tend to transfer through the food chains and potentially can cause adverse effects on the health of any organisms at any trophic level.

Objectives

Methods

Results

Discussion

Conclusion