Sorption Characteristics Of Hexavalent Chromium In The Soil Based On Batch Experiment And Their Implications To The Environment

Abstract

The objective of this experimental study was to determine the kinetics and

equilibrium sorption of Cr(VI) in soils collected from Hengshui City of Hebei

Province, China, based on batch experiments. The main concentration for this

paper is on the effect of soil pH, solute concentration and ionic strength as the

variable factors in the sorption of Cr(VI) in soils and the assessment of their

implications to the environment. Atomic Absorption Spectrophotometer

(AAS) was used for Cr(III) analysis; UV-VIS Spectrophotometer for quantification

of Cr(VI) in soil samples and determination of electrical conductivity

and temperature of the soil samples; and Automatic Laser Particle Size Analyzer

LS230 for the determination of soil physical characteristics. Results from

this study show that adsorption and reduction are major reactions accounting

for removal of Cr(VI) from soil solution. It is concluded that chemical reactions

such as reduction, strongly influence Cr(VI) mobility in soil. Adsorption

kinetics experiments indicated that Cr(VI) removal from soil solution increases

with increasing solute concentration, with decreasing pH and with

decreasing ionic strength. Adsorption reactions reached equilibrium within 12

hours in batch reactors. Increasing background electrolyte concentration

(KCI) decreases Cr(VI) adsorption on soil. The Cr(VI) adsorption isotherm

for this soils conforms well to the Langmuir isotherm at constant pH. Two

Cr(VI) adsorption parameters: the maximum sorption capacity (Qo) and

Langmuir adsorption constant (KL), were determined as 1.0135 × 10−4 mol/g

and 0.0622 mg/L, respectively. The reduction of Cr(VI) into less toxic Cr(III),

means reduction of significant environmental problems. Finally, this study

advises relevant environmental governing authorities to observeperiodic monitoring

of the status of Cr(VI) in soils.

How to cite this paper: Kwikima, M.M.

and Lema, M.W. (2017) Sorption Characteristics

of Hexavalent Chromium in the Soil

Based on Batch Experiment and Their

Implications to the Environment. Journal

of Geoscience and Environment Protection,

5, 152-164.

https://doi.org/10.4236/gep.2017.53011

Received: February 15, 2017

Accepted: March 26, 2017

Published: March 29, 2017

Copyright © 2017 by authors and

Scientific Research Publishing Inc.

This work is licensed under the Creative

Commons Attribution International

License (CC BY 4.0).

http://creativecommons.org/licenses/by/4.0/

Open Access