title: Influence of electrolyte and voltage on the direct current enhanced transport of iron nanoparticles in clay.
abstract: Zero valent iron nanoparticles (nZVI) transport for soil and groundwater remediation is slowed down or halted by aggregation or fast depletion in the soil pores. Direct electric current can enhance the transport of nZVI in low permeability soils. However operational factors, including pH, oxidation-reduction potential (ORP), voltage and ionic strength of the electrolyte can play an important role in the treatment effectiveness. Experiments were conducted to enhance polymer coated nZVI mobility in a model low permeability soil medium (kaolin clay) using low direct current. Different electrolytes of varying ionic strengths and initial pH and high nZVI concentrations were applied. Results showed that the nZVI transport is enhanced by direct current, even considering concentrations typical of field application that favor nanoparticle aggregation. However, the factors considered (pH, ORP, voltage and electrolyte) failed to explain the iron concentration variation. The electrolyte and its ionic strength proved to be significant for pH and ORP measured during the experiments, and therefore will affect aggregation and fast oxidation of the particles.
authors.affiliation: Department of Civil and Environmental Engineering, Fritz Engineering Laboratory, Lehigh University, 13 E. Packer Avenue, Bethlehem, PA 18015-4729, USA; CENSE, Departamento de Ciências e Engenharia do Ambiente, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal; CERNAS - Research Center for Natural Resources, Environment and Society, Escola Superior Agrária de Coimbra, Instituto Politécnico de Coimbra, Bencanta, 3045-601 Coimbra, Portugal. Electronic address: hrg@campus.fct.unl.pt.
authors.forename: Helena I
authors.initials: HI
authors.lastname: Gomes
authors.affiliation: CERNAS - Research Center for Natural Resources, Environment and Society, Escola Superior Agrária de Coimbra, Instituto Politécnico de Coimbra, Bencanta, 3045-601 Coimbra, Portugal.
authors.forename: Celia
authors.initials: C
authors.lastname: Dias-Ferreira
authors.affiliation: CENSE, Departamento de Ciências e Engenharia do Ambiente, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
authors.forename: Alexandra B
authors.initials: AB
authors.lastname: Ribeiro
authors.affiliation: Department of Civil and Environmental Engineering, Fritz Engineering Laboratory, Lehigh University, 13 E. Packer Avenue, Bethlehem, PA 18015-4729, USA.
authors.forename: Sibel
authors.initials: S
authors.lastname: Pamukcu
mesh_terms: D000538:Aluminum Silicates / Q000737:chemistry*; D000077215:Clay; D004560:Electricity; D004573:Electrolytes / Q000737:chemistry*; D052918:Environmental Restoration and Remediation / Q000379:methods*; D060587:Groundwater / Q000737:chemistry; D007501:Iron / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry; D012987:Soil / Q000737:chemistry; D012989:Soil Pollutants / Q000737:chemistry*
chemical_list: D000538:Aluminum Silicates; D004573:Electrolytes; D011108:Polymers; D012987:Soil; D012989:Soil Pollutants; D007501:Iron; D000077215:Clay
keywords: Electrokinetics (EK); Electrolyte; Oxidation–reduction potential (ORP); Voltage; Zero valent iron nanoparticles (nZVI)