Sorption of isoxaflutole and DKN on organoclays

• Published in: Clays and clay minerals Vol. 52; no. 3; pp. 341 - 349
• Main Authors: Carrizosa, María José, Rice, Pamela J, Koskinen, William C, Carrizosa, Ignacio, Hermosín, María del Carmen
• Format: Journal Article
• Language: English
• Published: Boulder, CO Clay Minerals Society 01.06.2004; The Clay Minerals Society
• Subjects: aliphatic hydrocarbons; alkanes; chemical properties; clay mineralogy; clay minerals; Degradation; Diketonitrile; Earth sciences; Earth, ocean, space; Exact sciences and technology; experimental studies; Freundlich; Geochemistry; hydrocarbons; hydrolysis; Hysteresis; ISOXAFLUTOLE; Mineralogy; organic compounds; Organoclays; paraffins; rock, sediment, soil; sed rocks, sediments; Sedimentary petrology; sheet silicates; Silicates; Sorption; experimental studies; Fourier transformation; cation exchange capacity; ion exchange; aqueous solutions; degradation; isotherms; sorption; hysteresis; molecular structure; paraffins; sheet silicates; silicates; clay minerals; desorption; hydrolysis; absorption spectra; herbicides; infrared spectroscopy
• ISSN: 0009-8604; 1552-8367
• DOI: 10.1346/CCMN.2004.0520309

Sorption of the herbicide isoxaflutole and its main degradate, diketonitrile (DKN), to natural clays, SAz-1, SWy-2 and SHCa-1, and the organoclay derivatives (octadecylammonium (ODA) and hexadecyltrimethylammonium (HDTMA)) of these clays was investigated. Isoxaflutole hydrolysis to DKN was too rapid in aqueous solutions with organoclays to characterize sorption. No measurable DKN sorption was observed for the natural clays. Sorption of DKN was greater on organoclays with an interlayer paraffin-like complex that were prepared from the high-charge SAz-1 clay than on organoclays with a bilayer or monolayer interlayer complex prepared using lower-charge SWy-2 or SHCa-1 clays. Desorption isotherms indicated that sorption was irreversible. For SAz-1 with HDTMA at ∼100% of the clay c.e.c., the d001 values suggest that DKN enters the interlamellar space of the organoclay and dissociates into the anion. The DKN anion forms a very stable chelate complex with the residual cations and/or partially-coordinated structural cations. This strong interaction supports the irreversibility of the sorptive process.