From structure evolution of palygorskite to functional material: A review

Palygorskite (PAL) is a modulated rod-like phyllosilicate with abundant reserves in nature, which has the characteristics of a 2:1 layered-chain crystal structure, one-dimensional nanorod crystal morphology, regularly arranged tunnels/channels, and rich surface active sites. In the long-term research process, various modification strategies have been conducted to adjust the order of the structure, regulate the pore structure, change the stacking pattern, and further optimize the morphological characteristics and surface properties of PAL to improve its application performance and expand its application range. Currently, it has been possible to manipulate the basic tetrahedron-octahedron of PAL and even self-assemble available components to promote the rearrangement or reconstruction of the PAL structure to transform into new mineral functional materials. Structural evolution provides a new approach for better application of PAL in wider fields. This article comprehensively reviews the different ways to induce the structural evolution of PAL to fabricate functional materials and emphasizes the sustainable development paths for the transformation and utilization of low-grade PAL clay with a variety of complex associated minerals. It is expected that the summary of the structural evolution process of PAL can help to understand the structure at a deeper level and develop novel functional materials in a wider dimension, ultimately facilitating the value-added, comprehensive, and ecological development of PAL clay resources.