Effect of mechanical milling on layered double hydroxides prepared with amines and hydrothermal treatment

Hydrotalcite-like solids are commonly subjected to thermal aging treatments in order to modify and homogenise their crystal and particle sizes; however, the samples can still show a large heterogeneity in their particle sizes. Mechanical milling is an alternative treatment that has been used to achieve the desired homogeneity in particle size. In this work, the effect of the application of a mechanical milling treatment on the morphological and textural properties of hydrotalcite-like solids synthesized in the presence of amines as precipitating agents was studied. The application of a mechanical milling treatment over the samples subjected to hydrothermal treatment was also studied, analysing the effect of both post-treatments on the final properties of these compounds. Once the samples were synthesized and characterised, a mechanical treatment was carried out in a ball mill with planetary geometry, where the solids were ground at a speed of 600 rpm for 30 min. The milled samples were studied attending to their morphological and textural properties, and non-agglomerated solids with smaller crystallite sizes were obtained. These results highlighted mechanical milling as an effective post-synthetic strategy to tailor the microstructural properties of layered double hydroxides (LDH), which may enhance their suitability for future catalytic and adsorptive applications.