Expanded vermiculite with excellent thermal and chemical stability was investigated as a reliable sorbent for hazardous liquid spillages, including those leading to fire and explosion risks. Many expanded samples were prepared by rapid heating using both different temperatures and dissimilar vermiculite dimensions. Their capabilities for hazard clean-up were correlated with the structural characteristics of expanded vermiculite with slit-shaped porosity. When using optimized vermiculite, the moderate sorption capacities of 1.5–3.0 g g−1 were obtained for various hazardous chemicals, including hydrophilic/hydrophobic organic chemicals and strongly acidic/basic solutions. The sorption capacities depended more strongly on physical properties, such as the pore volume of the sorbent and the density of the absorbed liquid, rather than the vermiculite's chemical composition. The void space interconnected by interparticle/intraparticle pores worked as imbibing pathways due to their capillarity, resulting in the rapid, spontaneous sorption of hazardous chemicals. The hazardous chemicals may be removed from a testing vessel via sorption with an efficiency of >94 wt.% for 10 min. These results demonstrate that the expanded vermiculite may be a potential candidate as a reliable general-purpose sorbent for hazardous materials clean-up under harsh conditions.

The use of clay materials as selective sorbents for different contaminants requires very efficient methods. A natural kaolinite was calcined to metakaolinite and than rehydrated at different temperatures to produce a highly porous sorbent. The kinetics of this process were measured, with subsequent IR characterization of the phases formed. The surface and pore distribution of new phases were also assigned. In addition, the kaolinite obtained was pre-treated with Fe3+ ions to improve its sorption affinity for anionic particles. The rehydrated kaolinite and its Fe-modification were used for the adsorption of toxic cations (Zn, Cd, Pb) and anions (As, Se). Adsorption capacities depending on the physical chemical properties of the initial solution (pH, concentration of toxic ions) and the surface properties of the sorbent (specific surface area, modification method) were investigated. The adsorption properties of the sorbents were defined by the Langmuir model.