LAUSR

Abstract Gamma-hexachlorocyclohexane, also known as lindane, is one of persistent organic pollutants that are harmful to humans and ecosystems. In order to detect and remove lindane, effective adsorption and enrichment of lindane are necessary. Porous materials can be used to treat pollutants, but their removal rate, adsorption capacity and desorption separation efficiency still need to be improved. In this work, hierarchically porous graphene materials (M-HPRGO) were prepared by microwave reduction and used for rapid and efficient adsorption of lindane. The obtained M-HPRGO exhibited secondary structure and high specific surface area due to its morphology with micron-scale stacked pores and nanoscale in-plane holes. These structural characteristics and residual oxygen-containing functional groups on the defects efficiently increased the contact of M-HPRGO with aqueous solution and exposed sufficient hydrophobic graphene domains to adsorb lindane by hydrophobic effect. In the adsorption process, M-HPRGO showed excellent removal ability, fast adsorption rate and high uptake capacity for lindane. Meanwhile, pH, temperature, metal ions and organic matters showed no significant influence on the adsorption performance of M-HPRGO. Moreover, the desorption process of adsorbed lindane was simple and complete, and the recycled M-HPRGO performed well in reusability. In addition, based on the outstanding adsorption and desorption performance of M-HPRGO for lindane, efficient enrichment of ultra-trace lindane was realized with over 100-fold concentration amplification, which could be used in sample pretreatment to significantly push down the detection limit of analytical equipment. The current results indicate that M-HPRGO not only has important implications for pollutant treatment, but also has practical application potential for ultra-trace pollutant detection.