ORIGINAL RESEARCH
Remediation Mechanism and Evaluation
for Cd Polluted Vegetable Soil using Palygorskite
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1
Taiyuan Institute of Technology, Taiyuan, 030008, China
2
Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin, 300191, China
Submission date: 2024-04-22
Final revision date: 2024-06-13
Acceptance date: 2024-06-28
Online publication date: 2024-09-18
Corresponding author
Jianrui Li
Taiyuan Institute of Technology, Taiyuan, 030008, China
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ABSTRACT
The field experiments were done to illuminate the remediation mechanisms and effects of
palygorskite on Cd (cadmium) polluted vegetable soils. The specific surface area, pore size distribution,
X-ray diffraction (XRD) pattern of palygorskite, and X-ray photoelectron spectroscopy (XPS) pattern
of Cd adsorption product were characterized to analyze the mechanisms of Cd immobilization by
palygorskite. The field trials investigated the influences of palygorskite on pH, CEC (cation exchange
capacity), available Cd in soils, concentrations of Cd and sulfur compounds in plants, and enzymatic
activity and microbial population in soils. The results showed palygorskite was a hydrated magnesia
aluminum silicate clay mineral, with a micropore and mesopore distribution and a specific surface area
of 135.7 m2/g. The available Cd in soils was reduced by 11.8%-49.0% after 0.5%-3.0% palygorskite
application, accompanied by 9.3%-55.8% reduction of Cd in the shoot of the plant (p<0.05). The rise
in pH of 0.06-0.90 units and maximum increase of 19.5% for CEC in treated soils were conducive to
a decline in Cd availability in soils (p<0.05). The 21.8%–50.6% increase for GSH (glutathione) and
22.7%–44.6% for PCs (plant chelating peptides) in shoots were observed in treated soils to upgrade
the ability of plants to resist Cd-induced oxidative stress. The changes in enzymatic activity and
microbial number demonstrated the recovery of microbial functions that occurred in amended soils.
The palygorskite application in a Cd polluted vegetable field was practicable in realizing the safety
regulation of plants and the restoration of soil microbial function.