Role of Natural and Modified Clay Minerals in Microbial Hydrocarbon Biodegradation

Microbial hydrocarbon degradation mediated by natural/modified clay minerals represents an eco-friendly and economically viable remediation strategy for hydrocarbon contamination. However, its effects are not always positive as they depend on multiple factors, including clay mineral types, modification methods, microbial species, and hydrocarbon substrates. This review systematically synthesizes existing fragmented studies concerning the impacts of natural clay minerals, modified clay minerals (acid/alkali/thermal/organic/metal ion), and clay minerals containing composite materials on microbial hydrocarbon biodegradation. Based on current findings, future research should prioritize the following recommendations: (1) avoid using concentrated strong acids in acid activation; (2) exclude metal cations that induce strong adsorption (reducing hydrocarbon bioavailability) or trigger excessive interlayer hydrolysis (some trivalent cations) in metal cation modification; (3) eliminate biologically toxic agents during organic modification; and (4) expand understanding of alkali/thermally modified clay minerals and clay mineral-containing composite materials in this direction. Natural/modified clay mineral-mediated microbial degradation is a highly promising remediation technology for hydrocarbon contamination and poised to advance and achieve breakthroughs through continuous synthesis of knowledge and innovation.