Recent developments in synthesis of attapulgite composite materials for refractory organic wastewater treatment: a review

Attapulgite clay, due to its unique crystalline hydrated magnesium-aluminium silicate composition and layer-chain structure, possesses exceptional adsorption and catalytic properties, which enable it or its composites to be utilized as adsorbents and catalysts for wastewater treatment. But the drawbacks of attapulgite are also very obvious, such as relatively low specific surface area (compared to traditional adsorbents such as activated carbon and activated alumina), easy aggregation, and difficulty in dispersion. In order to fully utilize and improve the performance of attapulgite, researchers have conducted extensive research on its modification, but few specialized works have comprehensively evaluated the synthesis, applications and challenges for attapulgite-based composite materials in refractory organic wastewater treatments. This paper provides a comprehensive review of controllable preparation strategies, characterization methods and mechanisms of attapulgite-based composite materials, as well as the research progress of these materials in refractory organic wastewater treatment. Based on this review, constructive recommendations, such as deep mechanism analysis from molecular level multi-functional attapulgite-based material developments, and using biodegradable materials in attapulgite-based composites, were proposed. A comprehensive review of preparations, characterization methods and mechanisms of attapulgite-based composite materials, as well as their applications in refractory organic wastewater treatment were provided.