Atrazine sorption by hydroxy-interlayered clays and their organic complexes

Abstract

This study examined the sorption of atrazine by hydroxy-Fe interlayered montmorillonite (FeMt) and its hydroquinone (FeMtHQ), citrate (FeMtCt) and catechol (FeMtCC) complexes as well as by hydroxy-Al interlayered montmorillonite (AlMt) and its hydroquinone (AlMtHQ) and citrate (AlMtCt) complexes. Found among the clays were sorption distribution coefficients (K(d)) ranging from 24 to 123 mL g(-1) and maximum sorption (M) ranging from 2.2 to 16.8 microg g(-1). Both K(d) and M decreased in the order of FeMtCC > FeMtHQ > AlMtHQ > (AlMt = FeMt) > (AlMtCt = FeMtCt). The pH was negatively correlated with both K(d) (r = -0.90, p < 0.001) and M (r = -0.81, p < 0.001). When interlayered clays were associated with humified material (FeMtCC, FeMtHQ, AlMtHQ), both K(d) (r > 0.96, p < 0.01) and M (r > 0.94, p < 0.01) were highly positively correlated with total organic C and alkali-soluble C. However, clays with non-humified organic compounds (FeMtCt and AlMtCt) sorbed less atrazine than clays without any organic C (FeMt and AlMt). This suggests that functional groups of Fe-OH and Al-OH in FeMt and AlMt reduced the available sorption sites for atrazine by making complexes with citrate ions while forming FeMtCt and AlMtCt. The atrazine was sorbed through the hydrophobic interactions with organic compound surfaces as well as through H-bonding and ionic bonding with clay-mineral surfaces.

Atrazine immobilization on sludge derived biochar and the interactive influence of coexisting Pb(II) or Cr(VI) ions

“…5). Similar conclusions were derived on biochar of pine needles by Chen et al (2008a,b), hydroxy-interlayered clays by Indraratne et al (2008) and activated carbons by Cao et al (2009). However, Cao et al (2009) found that little competition occurred between Pb and atrazine for sorption on dairy-mature derived biochar, because precipitation as Pb 9 (PO 4 ) 6 or Pb 3 (CO 3 ) 2 (OH) 2 and partitioning were respectively responsible for Pb and atrazine sorption there (Cao et al, 2009(Cao et al, , 2011.…”

Effects of two ecological earthworm species on atrazine degradation performance and bacterial community structure in red soil

“…which are the key environmental factors for atrazine degradation (Hickman and Reid, 2008;Indraratne et al, 2008;Wang et al, 2011). The acid dissociation constant (pKa) of atrazine is 1.68, and the ionized atrazine fraction therefore increases at higher soil pH and principally raises atrazine availability to microorganisms.…”

Novel Nanocrystal Clay Materials with Potential Bone Cells Growth Enhancement or Inhibition Characteristics <i>In Vitro</i>

“…The feature consisted of local ceramics with special assemblage with clay figurines, quartz querns, and biotite muscovite schist grinders [23]. An iron razor blade was recovered with the clay suggesting a causal linkage with some medical implications since the use of natural clay for cell growth and treatment of diseases has been extensively documented [24][25][26][27][28]. There are ethnographic parallels to the use of the clay in treating related ailments including fractured bones in Yikpabongo in the Northern Region of Ghana.…”