Strong adsorption of Polychlorinated Biphenyls by processed montmorillonite clays: Potential applications as toxin enterosorbents during disasters and floods

Potential Applications of Clay-Based Therapy for the Reduction of Pesticide Exposures in Humans and Animals

“…To develop broad-acting sorbents that can reduce exposures to diverse mixtures of environmental chemicals, we have treated montmorillonites with acid to increase their surface area and porosity, resulting in more active sites for toxin sequestration and binding. The safety of broad-acting APMs and their increased efficacy for aflatoxins, zearalenone, glyphosate, and PCBs have been previously described [24,25]. This study was designed to investigate the binding efficacy of APMs for widely used and highly toxic pesticides (individuals and mixtures) with different structural morphologies and modes of toxic action.…”

“…The final product of APMs consists of a mixture of delaminated parent clay layers containing chains of amorphous silica on the edges, amorphous silica, and cross-linked silica [ 25 , 26 , 46 ]. This polymorphic structure with diverse binding sites, higher surface area and enhanced porosity compared to the parent clays, can contribute to the increased binding efficacy for diverse chemicals observed in this study.…”

“…Synthesis of APMs was previously described [25]. Briefly, CM and SM were treated with sulfuric acid at two different concentrations (12 and 18N).…”

“…To develop broad-acting sorbents to mitigate pesticide exposures and toxicities, we have treated both calcium and sodium montmorillonite clays (CM and SM) with 12 and 18 normality sulfuric acid to produce high surface area and enhanced porosity. These acid-processed calcium and sodium montmorillonites (APCMs and APSMs) have been previously reported to bind hazardous mixtures of mycotoxins (aflatoxin and zearalenone), a commonly occurring herbicide (glyphosate) and polychlorinated biphenyls (PCBs) [ 24 , 25 ]. Based on earlier work with acid processed montmorillonite clays (APMs), we have postulated that treatment of clays with high concentrations of acid results in the exchange of interlayer cations with protons from the acid, followed by the dissolution of portions of the octahedral and tetrahedral framework in the clay structure [ 26 ].…”

“…Based on earlier work with acid processed montmorillonite clays (APMs), we have postulated that treatment of clays with high concentrations of acid results in the exchange of interlayer cations with protons from the acid, followed by the dissolution of portions of the octahedral and tetrahedral framework in the clay structure [ 26 ]. The final reaction product of acid treatment is postulated to be a mixture of delaminated parent clay with amorphous silica chains at the edges and porous amorphous silica formed from three-dimensional cross-linked SiO 4 [ 25 , 27 ]. Importantly, parent montmorillonite clays which were used as starting materials for the formation of APMs are safe for human and animal consumption [ 22 ].…”