Metal removal from soil leachates using DTPA-functionalised maghemite nanoparticles, a potential soil washing technology

TY - JOUR

T1 - Metal removal from soil leachates using DTPA-functionalised maghemite nanoparticles, a potential soil washing technology

AU - Hodson, Mark Edward

AU - Harwood, L

AU - Afsar, A

AU - Laventine, D

AU - Hughes, D

AU - Shaw, L

N1 - © 2018 Elsevier Ltd. All rights reserved. This is an author-produced version of the published paper. Uploaded in accordance with the publisher’s self-archiving policy.

PY - 2018/10

Y1 - 2018/10

N2 - There is significant current interest in the application of magnetic (magnetite or maghemite) nanoparticles functionalised with chelating agents for the environmental remediation of metal contaminated waters and solutions. Whilst there is a body of knowledge about the potential remediation efficacy of such engineered nanoparticles from studies involving synthetic solutions of single metals, there is relatively little data involving mixed-metal solutions and virtually no studies about nanoparticle performance in chemically complex environmental solutions representing those to which a scaled-up nanoremediation process might eventually be applied. Therefore, we investigated the ability of diethylenetriaminepentaacetic acid (DTPA)-functionalised, silica-coated maghemite nanoparticles to extract potentially toxic (Cd, Co, Cu) and “non-toxic” (Ca, Mg) metals from solution (initial [metal] = 10 mg L-1 ; pH range: 2-8) and to extract a wider range of elements (As, Ca, Cd, Co, Cr, Cu, Mg, Na, Pb, Zn) from leachate obtained from 10 different contaminated soils with variable initial pH, (semi-)metal and dissolved organic carbon (DOC) concentrations. The functionalised nanoparticles could extract the potentially toxic metals with high efficiency (in general >70%) from single metal solutions and with efficiencies that were either unaffected or reduced from the soil leachates. Kd values remained high (> 500 L kg-1), even for the soil leachate extractions. Our findings show that DOC and relatively high concentrations of non-toxic elements do not necessarily reduce the efficiency of metal contaminant removal by DTPA-functionalised magnetic nanoparticles and thus demonstrate the potential of this process when applied to chemically complex soil-derived contaminated solutions.

AB - There is significant current interest in the application of magnetic (magnetite or maghemite) nanoparticles functionalised with chelating agents for the environmental remediation of metal contaminated waters and solutions. Whilst there is a body of knowledge about the potential remediation efficacy of such engineered nanoparticles from studies involving synthetic solutions of single metals, there is relatively little data involving mixed-metal solutions and virtually no studies about nanoparticle performance in chemically complex environmental solutions representing those to which a scaled-up nanoremediation process might eventually be applied. Therefore, we investigated the ability of diethylenetriaminepentaacetic acid (DTPA)-functionalised, silica-coated maghemite nanoparticles to extract potentially toxic (Cd, Co, Cu) and “non-toxic” (Ca, Mg) metals from solution (initial [metal] = 10 mg L-1 ; pH range: 2-8) and to extract a wider range of elements (As, Ca, Cd, Co, Cr, Cu, Mg, Na, Pb, Zn) from leachate obtained from 10 different contaminated soils with variable initial pH, (semi-)metal and dissolved organic carbon (DOC) concentrations. The functionalised nanoparticles could extract the potentially toxic metals with high efficiency (in general >70%) from single metal solutions and with efficiencies that were either unaffected or reduced from the soil leachates. Kd values remained high (> 500 L kg-1), even for the soil leachate extractions. Our findings show that DOC and relatively high concentrations of non-toxic elements do not necessarily reduce the efficiency of metal contaminant removal by DTPA-functionalised magnetic nanoparticles and thus demonstrate the potential of this process when applied to chemically complex soil-derived contaminated solutions.

KW - metal

KW - nanoparticle

KW - magnetic

KW - maghemite

KW - soil

KW - remediation

KW - DTPA

U2 - 10.1016/j.chemosphere.2018.06.121

DO - 10.1016/j.chemosphere.2018.06.121

M3 - Article

SN - 0045-6535

VL - 209

SP - 480

EP - 488

JO - CHEMOSPHERE

JF - CHEMOSPHERE

ER -