Coating of AFM probes with aquatic humic and non-humic NOM to study their adhesion properties

Handle URI:
http://hdl.handle.net/10754/562787
Title:
Coating of AFM probes with aquatic humic and non-humic NOM to study their adhesion properties
Authors:
Aubry, Cyril; Gutiérrez, Leonardo A.; Croue, Jean-Philippe
Abstract:
Atomic force microscopy (AFM) was used to study interaction forces between four Natural Organic Matter (NOM) samples of different physicochemical characteristics and origins and mica surface at a wide range of ionic strength. All NOM samples were strongly adsorbed on positively charged iron oxide-coated silica colloidal probe. Cross-sectioning by focused ion beam milling technique and elemental mapping by energy-filtered transmission electron microscopy indicated coating completeness of the NOM-coated colloidal probes. AFM-generated force-distance curves were analyzed to elucidate the nature and mechanisms of these interacting forces. Electrostatics and steric interactions were important contributors to repulsive forces during approach, although the latter became more influential with increasing ionic strength. Retracting force profiles showed a NOM adhesion behavior on mica consistent with its physicochemical characteristics. Humic-like substances, referred as the least hydrophilic NOM fraction, i.e., so called hydrophobic NOM, poorly adsorbed on hydrophilic mica due to their high content of ionized carboxyl groups and aromatic/hydrophobic character. However, adhesion force increased with increasing ionic strength, suggesting double layer compression. Conversely, polysaccharide-like substances showed high adhesion to mica. Hydrogen-bonding between hydroxyl groups on polysaccharide-like substances and highly electronegative elements on mica was suggested as the main adsorption mechanism, where the adhesion force decreased with increasing ionic strength. Results from this investigation indicated that all NOM samples retained their characteristics after the coating procedure. The experimental approach followed in this study can potentially be extended to investigate interactions between NOM and clean or fouled membranes as a function of NOM physicochemical characteristics and solution chemistry. © 2013 Elsevier Ltd.
KAUST Department:
Water Desalination and Reuse Research Center (WDRC); Water Desalination & Reuse Research Cntr; Biological and Environmental Sciences and Engineering (BESE) Division
Publisher:
Elsevier BV
Journal:
Water Research
Issue Date:
Jun-2013
DOI:
10.1016/j.watres.2013.03.023
PubMed ID:
23587263
Type:
Article
ISSN:
00431354
Appears in Collections:
Articles; Water Desalination and Reuse Research Center (WDRC); Biological and Environmental Sciences and Engineering (BESE) Division

Full metadata record

DC FieldValue Language
dc.contributor.authorAubry, Cyrilen
dc.contributor.authorGutiérrez, Leonardo A.en
dc.contributor.authorCroue, Jean-Philippeen
dc.date.accessioned2015-08-03T11:05:44Zen
dc.date.available2015-08-03T11:05:44Zen
dc.date.issued2013-06en
dc.identifier.issn00431354en
dc.identifier.pmid23587263en
dc.identifier.doi10.1016/j.watres.2013.03.023en
dc.identifier.urihttp://hdl.handle.net/10754/562787en
dc.description.abstractAtomic force microscopy (AFM) was used to study interaction forces between four Natural Organic Matter (NOM) samples of different physicochemical characteristics and origins and mica surface at a wide range of ionic strength. All NOM samples were strongly adsorbed on positively charged iron oxide-coated silica colloidal probe. Cross-sectioning by focused ion beam milling technique and elemental mapping by energy-filtered transmission electron microscopy indicated coating completeness of the NOM-coated colloidal probes. AFM-generated force-distance curves were analyzed to elucidate the nature and mechanisms of these interacting forces. Electrostatics and steric interactions were important contributors to repulsive forces during approach, although the latter became more influential with increasing ionic strength. Retracting force profiles showed a NOM adhesion behavior on mica consistent with its physicochemical characteristics. Humic-like substances, referred as the least hydrophilic NOM fraction, i.e., so called hydrophobic NOM, poorly adsorbed on hydrophilic mica due to their high content of ionized carboxyl groups and aromatic/hydrophobic character. However, adhesion force increased with increasing ionic strength, suggesting double layer compression. Conversely, polysaccharide-like substances showed high adhesion to mica. Hydrogen-bonding between hydroxyl groups on polysaccharide-like substances and highly electronegative elements on mica was suggested as the main adsorption mechanism, where the adhesion force decreased with increasing ionic strength. Results from this investigation indicated that all NOM samples retained their characteristics after the coating procedure. The experimental approach followed in this study can potentially be extended to investigate interactions between NOM and clean or fouled membranes as a function of NOM physicochemical characteristics and solution chemistry. © 2013 Elsevier Ltd.en
dc.publisherElsevier BVen
dc.subjectAdhesion force curvesen
dc.subjectAtomic force microscopeen
dc.subjectEELSen
dc.subjectEPMen
dc.subjectFIBen
dc.subjectNatural organic matteren
dc.subjectTEMen
dc.titleCoating of AFM probes with aquatic humic and non-humic NOM to study their adhesion propertiesen
dc.typeArticleen
dc.contributor.departmentWater Desalination and Reuse Research Center (WDRC)en
dc.contributor.departmentWater Desalination & Reuse Research Cntren
dc.contributor.departmentBiological and Environmental Sciences and Engineering (BESE) Divisionen
dc.identifier.journalWater Researchen
dc.contributor.institutionDepartment of Civil and Environmental Engineering, Center of Advanced Materials for the Purification of Water with Systems, University of Illinois at Urbana-Champaign, United Statesen
kaust.authorAubry, Cyrilen
kaust.authorCroue, Jean-Philippeen
kaust.authorGutiérrez, Leonardo A.en
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