Magnetic layered double hydroxide-based composites as sustainable adsorbent materials for water treatment applications: Progress, challenges, and outlook

Muhammad Sajid; Ihsanullah Ihsanullah

doi:10.1016/j.scitotenv.2023.163299

Magnetic layered double hydroxide-based composites as sustainable adsorbent materials for water treatment applications: Progress, challenges, and outlook

Sci Total Environ. 2023 Jul 1:880:163299. doi: 10.1016/j.scitotenv.2023.163299. Epub 2023 Apr 6.

Authors

Muhammad Sajid¹, Ihsanullah Ihsanullah²

Affiliations

¹ Applied Research Center for Environment and Marine Studies, Research Institute, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia. Electronic address: msajid@kfupm.edu.sa.
² Chemical and Water Desalination Engineering Program, College of Engineering, University of Sharjah, Sharjah 27272, United Arab Emirates.

PMID: 37030386
DOI: 10.1016/j.scitotenv.2023.163299

Abstract

Layered double hydroxides (LDHs) have shown exciting applications in water treatment because of their unique physicochemical properties, which include high surface areas, tunable chemical composition, large interlayer spaces, exchangeable content in interlayer galleries, and ease of modification with other materials. Interestingly, their surface, as well as the intercalated materials within the layers, play a role in the adsorption of the contaminants. The surface area of LDH materials can be further enhanced by calcination. The calcined LDHs can reattain their structural features upon hydration through the "memory effect" and may uptake anionic species within their interlayer galleries. Besides, LDH layers are positively charged within the aqueous media and can interact with specific contaminants through electrostatic interactions. LDHs can be synthesized using various methods, allowing the incorporation of other materials within the layers or forming composites that can selectively capture target pollutants. They have been combined with magnetic nanoparticles to improve their separation after adsorption and enhance adsorptive features in many cases. LDHs are relatively greener materials because they are mostly composed of inorganic salts. Magnetic LDH-based composites have been widely employed for the purification of water contaminated with heavy metals, dyes, anions, organics, pharmaceuticals, and oil. Such materials have shown interesting applications for removing contaminants from real matrices. Moreover, they can be easily regenerated and used for several adsorption-desorption cycles. Magnetic LDHs can be regarded as greener and sustainable because of several green aspects in their synthesis and reusability. We have critically reviewed their synthesis, applications, factors affecting their adsorption performance, and related mechanisms in this review. In the end, some challenges and perspectives are also discussed.

Keywords: Anions; Heavy metals; Magnetic materials; Organic pollutants; Sustainable adsorbents; Water treatment.

Publication types

Review