Fixed-Bed Adsorption of Lead from Aqueous Solution Using Chitosan-Coated Bentonite.

Cybelle Morales Futalan,Meng-Wei Wan

doi:10.3390/ijerph19052597

Abstract

In this study, fixed-bed adsorption of Pb(II) from an aqueous solution using chitosan-coated bentonite (CCB) was investigated. Characterization of CCB was performed using Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The effects of varying bed height (1.3 to 4.3 cm), flow rate (0.20 to 0.60 mL/min), and initial concentration (500 to 1500 mg/L) on the length of mass transfer zone (Zm) and adsorption capacity at breakthrough (qb) and exhaustion (qe) were examined. Low flow rate and high bed height were determined to cause a longer time to reach breakthrough and exhaustion. Meanwhile, the fixed-bed system was observed to quickly attain breakthrough and exhaustion under high initial concentrations. Kinetic column models such as the Thomas, Yoon–Nelson, and Clark models were used to predict the breakthrough curves. High R2 values (0.9758 ≤ R2 ≤ 0.8087) were attained for the Thomas model, which indicates that there is good agreement between experimental data and linear plots generated by the Thomas model. Moreover, the Thomas model is best in describing the breakthrough curves of Pb(II) removal under a fixed-bed system.

Highlights

Academic Editors: Elena RadaHeavy metal contamination in water bodies has always been a critical environmental concern worldwide
The present work examined the adsorptive removal of Pb(II) from an aqueous solution under a fixed-bed system
Breakthrough and exhaustion times were observed to increase with increasing bed height, decreasing flow rate, and low initial concentrations

Summary

Introduction

Heavy metal contamination in water bodies has always been a critical environmental concern worldwide. Pb(II) in waste streams are mainly generated by several anthropogenic activities including mining, ammunition and explosives manufacturing, the ceramic industry, e-wastes, paint manufacturing, and battery production [4,5]. The discharge of untreated wastewater containing Pb(II) is detrimental to both the environment and human health. Diseases such as anemia, damage to the kidney and nervous system, mental retardation, cardiovascular disease, cognitive impairment, and infertility in men have been associated with long-term exposure to Pb(II) [7]. High accumulation of Pb(II) in plants has negative effects such as stunted plant growth, decreased CO2 fixation capacity, and lower production of leaves and biomass [8,9]. The maximum contaminant level of Pb(II) in drinking water has been fixed at 0.015 mg/L by the United States Environmental

Methods

Discussion

Conclusion