Influence of trace elements on the textural properties of synthetic chrysotile: Complementary insights from macroscopic and nanoscopic measurements

The present study shows that the presence of Li, Sb, As and B as trace elements significantly influences textural properties such as particle size distribution, morphology and specific surface area of chrysotile synthesized under hydrothermal conditions (P = 8.2 MPa, T = 300 degrees C and high-alkaline pH (13.5)). Conversely, traces of Cs did not have any textural effect under these conditions. Furthermore, chrysotile nanotubes size and morphology depend strongly on the element considered. Indeed, large chrysotile with cylinder in cylinder morphology (outer diameter up to 50 nm) precipitated in the presence of Li, Sb and As. This implies lower specific surface area (124-160 m(2) g(-1)) compared to undoped chrysotile (184 m(2) g(-1) with about 14 nm in width). The presence of boron favors the precipitation of thin fibrous nanotubes similar to undoped chrysotile in width, but significantly longer, with tubes length that can reach three microns in length. In this case, the specific surface area increase slightly from 184 to 196 m(2)/g. The solid-liquid partition coefficient for each investigated trace element was determined using Langmuir equation. This well-tubular geo-material can be used as a model to better understand the effects of trace elements on the precipitation of minerals that are relevant in Earth systems (e.g., serpentinization processes) and societal applications (e.g., asbestos toxicity and CO2 sequestration). (C) 2013 Elsevier Inc. All rights reserved.