Exploring heavy metal migration and recovery using low power electrokinetic technology and plant microbial fuel cells

Qian, Hang 2025. Exploring heavy metal migration and recovery using low power electrokinetic technology and plant microbial fuel cells. PhD Thesis, Cardiff University. Item availability restricted.

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Abstract

This thesis investigates how low-power electrokinetics (LPEK; 0.01–0.05 V cm⁻¹) and plant microbial fuel cells (PMFCs) can be used as low-impact, low-power strategies to bias heavy metal transport and recovery from metal-bearing wastes and contaminated soils within a circular-economy framing. Chapter 1 sets the motivation and defines three linked questions: what weak electric fields can realistically achieve in porous media, whether PMFCs can access recalcitrant metal pools through plant–electrode synergy, and how these ideas translate to authentic, strongly buffered wastes. Chapter 2 reviews electrokinetic transport, electrolysis driven geochemical side effects, and PMFC principles, highlighting why conventional high gradient EK can be effective yet disruptive, and why “gentle” fields need a different performance yardstick. Chapter 3 establishes a quantitative transport ceiling in compacted, sorbing clay-rich media: weak gradients preserve compatibility and stability but imply decade scale timescales for large-scale redistribution, reframing LPEK/PMFC as a long-term steering force rather than a rapid bulk-depletion tool. Chapter 4 shows that weak fields become practically effective when mobilisation (rhizosphere-generated dissolved Cu) rather than transport is rate-limiting, because electromigration can maintain directional fluxes and convert mobilisation into plant capture instead of water-phase accumulation—yielding a near-doubling of recovery versus plants alone. Chapter 5 demonstrates in real Pb–Zn tailings that PMFCs can deliver element-specific benefits by strengthening sinks (vegetated capture) and limiting aqueous leakage while shifting reactive (F1–F3) pools. Overall, the thesis advances a unifying interpretation: PMFC/LPEK systems are best evaluated by how effectively they guide the small, continuously resupplied mobile pool toward safer or recoverable sinks, rather than by expecting rapid removal of the total solid-bound inventory.

Item Type:	Thesis (PhD)
Date Type:	Completion
Status:	Unpublished
Schools:	Schools > Engineering
Uncontrolled Keywords:	1. Plant microbial fuel cell 2. Resource recovery 3. Heavy metal migration and recovery 4. Electrokinetic 5. Mining tailing 6. Soil contamination
Date of First Compliant Deposit:	22 July 2026
Last Modified:	22 Jul 2026 14:02
URI:	https://orca.cardiff.ac.uk/id/eprint/188397

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