Adsorption Property of Pb(II) by the Laterite-Bentonite Mixture Used as Waste Landfill Liner

Yong-Gui Chen,Xue-Min Liu,Yu-Jun Cui,Wei-Min Ye,Hong-Nan Lei

doi:10.1155/2019/2879156

Abstract

To assess the potential use of laterite-bentonite mixture as waste landfill liner, a range of batch tests were conducted to study the influence of contact time, solid to solution ratio, pH, ion strength, and temperature on Pb(II) adsorption. The experimental results showed that the uptake of Pb(II) by laterite-bentonite mixture increases with the increase of contact time and the adsorption equilibrium can be reached within 30 minutes. This process can be delineated well using a pseudo-second-order kinetics equation. Besides, with the increase of solid to solution ratio (s/w) and pH, Pb(II) will be adsorbed more by the laterite-bentonite mixture. However, the uptake of Pb(II) will decrease when ion strength rises in the solution and this is due to the competitive adsorption and cation exchange between different cations. When conducting the batch test at 298 K and 323 K, respectively, the experiment results showed significant growth when temperature increases because the adsorption process is an endothermic reaction. This influence of temperate can be described better by the Langmuir isotherm model than that by the Freundlich isotherm model. In each experiment condition, the uptake of Pb(II) increases with the increasing of bentonite content, indicating a good improvement in the effect of bentonite on laterite used as landfill liner.

Highlights

With the economic and social development of many countries in the past few decades, industrialization and urbanization grew rapidly along with the great increase in both industrial and municipal solid waste production
An effective way to restrict the migration of toxic ions is the usage of a liner to absorb these metal ions and separate the environment from municipal solid waste (MSW) [5]
E GMZ bentonite was sampled from Gaomiaozi township in Northern China, and it had been air-dried and sieved (0.5 mm sieve) for use. e basic properties of this light-grey powder are listed in Table 2 [28, 29]

Summary

Introduction

With the economic and social development of many countries in the past few decades, industrialization and urbanization grew rapidly along with the great increase in both industrial and municipal solid waste production. In China, the overall volume of municipal solid waste (MSW) increases at a rate of 5% to 8% per year, making the effective disposal of pollution becoming an urgent environmental problem. The leachate, a poisonous and harmful liquid, forms in the process due to the underground water and precipitation, and it contains many heavy metal ions such as Zn(II), Pb(II), Cr(III), Cd(II), Ni(II), and Cu(II) [2]. If these toxic metals move out of the landfills by advection and diffusion, the surrounding environment may be contaminated and the health of living plants and animals will be jeopardized [3, 4]. An effective way to restrict the migration of toxic ions is the usage of a liner to absorb these metal ions and separate the environment from MSW [5]

Methods

Results

Conclusion