Study of a ternary system silica/humic acids/iodine: Capabilities of the nuclear microprobe

Nuclear microprobe by coupling the resonant nuclear reaction C-12(p, p) C-1 2 and proton-induced X-ray emission (PIXE) at 1.725 MeV has showed its capa bilities to study a ternary system silica slide/humic acids (HA)/iodine. Th e nuclear reaction on carbon-12 permits the determination of thickness (fro m 8 nm to 2.5 mum) of HA films sorbed on mineral surfaces, whereas PIXE sim ultaneously allows the quantification of trace elements scavenged by HA. Th e results obtained on the ternary system have evidenced a heterogeneous dis tribution of HA onto silica slides (presence of organic clusters of variabl e thickness) and confirmed the trace elements/organic matter association. M oreover, the data suggest a role played by HA in the retention of iodine on to silica slide surfaces. (C) 2001 Published by Elsevier Science B.V.