Electrokinetic delivery of permanganate in clay inclusions for targeted contaminant degradation.
J Contam Hydrol
; 251: 104102, 2022 12.
Article
in En
| MEDLINE
| ID: mdl-36372631
ABSTRACT
The use of electrokinetics (EK) has great potential to deliver reactants in impervious porous media, thus overcoming some of the challenges in the remediation of contaminants trapped in low-permeability zones. In this work we experimentally investigate electrokinetic transport in heterogeneous porous media consisting of a sandy matrix with a target clay inclusion. We demonstrate the efficient EK-delivery of permanganate in the target clay zone (transport velocity 0.3-0.5 m day-1) and its reactivity with Methylene Blue, a positively charged contaminant trapped within the inclusion. The delivery method was optimized using a KH2PO4/K2HPO4 buffer to attenuate the effect of electrolysis reactions in the electrode chambers, thus mitigating the propagation of pH fronts and preventing the phenomenon of permanganate stalling. The experiments showed that the buffer electrical conductivity greatly impacts the potential gradient in the heterogeneous porous medium with implications on the observed rates of electrokinetic transport (variation up to 40%). The reactive experiments provided direct evidence of the permanganate penetration within the clay and of its capability to degrade the target immobilized contaminant. The experimental results were analyzed using a process-based model, elucidating the governing transport mechanisms and highlighting the effect of different mass transfer processes on conservative and reactive electrokinetic transport.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Soil Pollutants
/
Environmental Restoration and Remediation
Language:
En
Journal:
J Contam Hydrol
Journal subject:
TOXICOLOGIA
Year:
2022
Document type:
Article
Affiliation country:
Italy