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Highlights • Complexation of Hg with the antibiotics resulting in the dissolution of Hg compounds from the sediment. • Hg ions in the sediment can also promote the degradation of antibiotics. • The degradation of TC/OTC radicals generates CH3+ groups which can react with Hg° to form MeHg. Abstract The role of antibiotics commonly used in fish culture activities in methylmercury (MeHg) formation in mariculture sediments (MS) and in reference sediments (RS) was studied using simulation microcosms. MS and RS were split into three equal batches. Two batches were spiked with Hg(NO 3) 2 aqueous solution at levels of 2 and 8 mg kg−1 (dry weight basis) and the remainder served as a control batch. Tetracycline (TC) and oxytetracycline (OTC) (2.5 g and 10 g of each) were added to each treatment. Sediment THg concentration decreased during the culture period possibly due to complexation of Hg with the antibiotics resulting in the dissolution of Hg compounds from the sediment. More importantly, the MeHg concentration increased after 32 days together with a decrease in the concentrations of the antibiotics in the sediment. The complexation of TC or OTC with Hg resulted in the transport of electrons from TC or OTC to Hg2+ due to the high electronegativity of Hg2+. Subsequently, Hg2+ was reduced to Hg° which reacted with CH 3 + derived from TC or OTC. The use of antibiotics may therefore promote the formation of MeHg in sediments. [ABSTRACT FROM AUTHOR]

• The 3D structure carbon aerogel with highly dispersed SnO 2 nanoparticles was synthesized. • The sorbent exhibited high Hg0 and H 2 S capture capacities and excellent regeneration performance. • The core-shell structure is beneficial for the resistance to H 2 O. • E-R adsorption mechanism of H 2 S and Hg0 was conformed. A seaweed-templated pathway was developed for the controllable synthesis of SnO 2 /carbon aerogel for the simultaneous removal of Hg0 and H 2 S in natural gases, where the SnO 2 nanoparticles with an outer diameter of 4–20 nm were highly dispersed and conjoined by graphitic carbon, forming a 3D core-shell structure with a developed pore network. The synthesized sorbent performed a complete removal of Hg0 and H 2 S at a high space velocity of 70,000 h−1 and showed resistance to water. At 5% breakthrough, the Hg0 and H 2 S capture capacities reached as high as 10.37 mg g−1 and 392.23 mg g−1, respectively, which are much higher than those of the existing commercial sorbents. More importantly, the spent sorbent could be easily regenerated without significant performance degradation over five cycles. The 3D interconnected macro- and mesopores are beneficial for the Hg0 and H 2 S removal at a high space velocity, and the core-shell structure is conducive to prevent poisoning from water. The Hg0 and H 2 S removal over the SnO 2 /aerogel conforms to the E-R mechanism, where H 2 S is first adsorbed and dissociated on the SnO 2 surface to produce active sulfur species, and the adsorbed sulfur then reacts with gaseous Hg0 to form HgS. [ABSTRACT FROM AUTHOR]