Performance of composite mineral adsorbents for removing Cu, Cd, and Pb ions from polluted water

Eun-Kyeong Choi,Sung Wook Kim,Chang-Han Lee,Seung Nam Seo,Se-Yeong Hamm,Heung-Jai Park,Woo-Ri Lim,Myoung Hak Oh

doi:10.1038/s41598-019-49857-9

Abstract

This study evaluated the efficiency of the removal of heavy metals from contaminated water via adsorption isotherm and kinetic experiments on two composite mineral adsorbents, CMA1 and CMA2. The developed CMA1 (zeolite with clinoptilolite of over 20 weight percent and feldspar of ~10 percent, with Portland cement) and CMA2 (zeolite with feldspar of over 15 weight percent and ~9 percent clinoptilolite, with Portland cement) were applied to remove Cu, Cd, and Pb ions. Based on the adsorption isotherm and kinetic experiments, the adsorbents CMA1 and CMA2 exhibited high removal efficiency for Cu, Cd, and Pb ions in solution compared to other adsorbents. In the adsorption kinetic experiment, CMA2 demonstrated better adsorption than CMA1 with the same initial concentration and reaction time, and Cu, Cd, and Pb ions almost reached equilibrium within 180 min for both CMA1 and CMA2. The results of the adsorption kinetic experiments with pseudo-first-order (PFO) and pseudo-second-order (PSO) models indicated that the PSO model was more suitable than the PFO model. Comparing the Langmuir and Freundlich adsorption isotherm models, the former showed a very slightly higher correlation coefficient (r2) than the latter, indicating that the two models can both be applied to heavy metal solutions on a spherical monolayer surface with a weak heterogeneity of the surface. Additionally, the adsorbents CMA1 and CMA2 demonstrated different removal abilities depending on which heavy metals were used.

Highlights

Substantial research has been conducted in the past 20 years on which materials are best for adsorbing heavy metals (Table 1)
We evaluated the cation adsorption performance and adsorption equilibrium characteristics of the composite mineral adsorbents CMA1 and CMA2 through adsorption isotherms and kinetics
The adsorption performance and adsorption equilibrium characteristics of the heavy metal ions were evaluated through adsorption isotherm and adsorption kinetic experiments

Summary

Introduction

Substantial research has been conducted in the past 20 years on which materials are best for adsorbing heavy metals (Table 1). Since commercial clinoptilolite is relatively costly, mixtures of zeolite and other less expensive organic and inorganic materials, such as cement, clays, and polymers, have been formulated for specific pollutants[14] Functionalized adsorbents such as nanocomposite materials have been prepared for harmful heavy metal ions and organic compound adsorption and have been used for diverse applications[15,16,17,18,19,20,21,22,23]. This study aimed to reveal the efficiency of the removal of heavy metals by applying modified natural minerals as adsorbents to contaminated groundwater For this purpose, we evaluated the cation adsorption performance and adsorption equilibrium characteristics of the composite mineral adsorbents CMA1 (zeolite with clinoptilolite of over 20 weight percent and feldspar of ~10 percent, with Portland cement) and CMA2 (zeolite with feldspar of over 15 weight percent and ~9 percent of clinoptilolite, with Portland cement) through adsorption isotherms and kinetics. We looked at how CMA1 and CMA2 performed in the removal of Cu, Cd, and Pb ions from polluted water

Objectives

Methods

Results

Conclusion