Hybrid colloidal suspensions tailored as gels to remove radioactive bitumen stains

Colloidal gel as an efficient process to treat Chemical, Biological, Radiological (CBR) and prion contaminated solid surfaces

“…The 137 Cs γ activities measured on the stainless plates, before and after application of fresh samples of CBR gel and NaOH gel are listed in Table 2 along with the calculated decontamination factors. The decontamination factors are similar to those obtained with a vacuumable gel specifically designed for nuclear applications [19,20,[22][23][24], where decontamination factors of 15-20 are considered satisfactory. The CBR gel is therefore suitable for radiological decontamination.…”

“…These gels, also named "vacuumable gels", consist of a surface-adapted decontaminating solution in which inorganic particles (typically silica or alumina) are used as a thickening agent and dispersed in a decontaminating solution to form a gel-like concentrated colloidal suspension. The gel's viscosity decreases under shearing but returns almost immediately, making them easy to implement at large scale and at a distance from the contamination by spraying [19,22,23]. The gels remain attached even to vertical surfaces, increasing the contact time between the decontaminating solution contained in the gel and the contaminated surface.…”

“…The gels crack as they dry to form non-dusting solid flakes in which the contaminants are trapped and which are easily to remove by brushing or vacuum cleaning. Vacuumable gels have recently been applied to treat other surfaces, such as bitumen stains [22], and other contaminants, such as heavy metals [24]. Based on our experience in the formulation of active colloidal gels, we have been investigating the possibility of using vacuumable gels to treat building materials contaminated by CBR agents.…”

Effect of Surfactant Concentration on the Long-Term Properties of a Colloidal Chemical, Biological and Radiological (CBR) Decontamination Gel

“…Initially developed for the radiological decontamination of metallic surfaces [1,7,8], this technology has been expanded to applications such as depollution [3] and the elimination of sticky bitumen layers [9]. Similar gels have also been formulated for the chemical, biological, and radiological (CBR) decontamination of solid surfaces [2,4], with hypochlorite ions and sodium hydroxide added to the decontaminating solution to treat biological and chemical contamination.…”