TITLE:
Stability of Soil and Biosolid Nanocolloid and Macrocolloid Particles in the Absence and Presence of Arsenic, Selenium, Copper and Lead
AUTHORS:
Jessique Ghezzi, Anastasios Karathanasis, Chris Matocha, Jason Unrine, Yvonne Thompson
KEYWORDS:
Nanocolloids, Macrocolloids, Colloid Stability, Contaminant Transport, Nanoparticles
JOURNAL NAME:
Open Journal of Soil Science,
Vol.4 No.7,
July
16,
2014
ABSTRACT: Due to their enhanced stability and contaminant transport potential,
environmental nanoparticles derived from soil and biosolid materials may pose a
considerable risk to groundwater quality. Very little information exists on the
stability and transportability of environmental or natural nanocolloids in the
presence of As, Se, Pb and Cu contaminants, all of which are considered to
represent substantial threats to human and animal populations through
groundwater contamination. This study involved stability settling experiments
of nanocolloids (NCs) (-1 of As, Se, Pb
and Cu. The results indicated greater stability in the mineral than the
biosolid colloid fractions, and enhanced stability of NCs over corresponding
MCs in the presence or absence of contaminants at low contaminant loads. At
high contaminant loads nearly all colloids were unstable except for the
bio-nanocolloids which still sustained considerable stability. At low
contaminant loads, the MC fraction stability sequence was smectitic > mixed >
kaolinitic > biosolid. Among the nano-fractions, the smectitic and
kaolinitic colloids demonstrated lower stability than the MCs, but higher than
those of the mixed and biosolid fractions. Physicochemical characterizations
indicated that extensive organic carbon surface coatings and higher Al/Fe:Si
ratios may have induced higher stability in the NC fractions, but their overall
stability may also have been hindered in some cases by nano-aggregation
phenomena.