حسن نوروزي

This study investigated the experimental performance an‎d mathematical modeling of bioelectrokinetic remediation of clayey soils contaminated with hexavalent chromium [Cr(VI)] in the presence of an organic carbon source (glucose). Experiments were conducted in a custom-designed electrokinetic cell consisting of a rectangular polymeric chamber (14×8×5 cm^3) with a central compartment for contaminated soil an‎d two end chambers for the electrolytes. The soil used was clayey with a moisture content of 20% an‎d was artificially contaminated with 500 mg Cr(VI)/kg using potassium dichromate. A total of 250 g of contaminated soil was treated over eight days under four different systems: non-biological control (Blank), bioremediation (Bio), electrokinetic (EK), an‎d combined bioelectrokinetic remediation (BioEK). Glucose was applied at three levels (0, 1, an‎d 2% w/w), an‎d a 10% (w/w) microbial inoculum was added to the biological systems. An electric potential gradient of 1 V/cm was applied to the EK an‎d BioEK systems. The results demonstrated that combined action of the electric field, microbial activity, an‎d organic carbon in the BioEK system led to the highest remediation efficiency. The overall removal efficiencies of Cr(VI) in the Blank, Bio, an‎d EK systems were approximately 25, 40, an‎d 80%, respectively, while the BioEK system achieved more than 89% removal in the presence of 2% glucose. Even a moderate glucose concentration significantly enhanced BioEK performance, whereas its effect was limited in systems without an applied electric field. Analysis of glucose concentration revealed that its depletion occurred much faster in electrokinetic systems, being nearly identical in EK an‎d BioEK, indicating the significant role of field-induced abiotic oxidation. In the modeling section, an extended Nernst–Planck–Poisson framework integrated with microbial kinetics based on the Monod an‎d dual Monod models was developed to simultaneously describe Cr(VI) transport an‎d bioreduction processes. The model accurately reproduced Cr(VI) removal dynamics, biomass growth, glucose consumption, an‎d microbial reduction behavior, showing excellent agreement with the experimental data. Overall, the findings confirm that the bioelectrokinetic system, by harnessing the synergistic effects of electrokinetic transport, microbial activity, an‎d organic carbon supplementation, provides an effective an‎d sustainable approach for the remediation an‎d detoxification of Cr(VI)-contaminated clay soils.

پالايش بيوالكتروسينتيك , كروم شش‌ظرفيتي , گلوكز , مدل‌سازي , سينتيك‌ ميكروبي

Bioelectrokinetic remediation , Hexavalent chromium , Glucose , Modeling , Microbial kinetics

Hassan Norouzi

Dr Parisa Hejazi