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Copper and zinc composite oxides (Cu2O/ZnO) were synthesized by an impregnation-reduction-air oxidation method. A series of Cu2O/ZnO/rGO ternary composites were prepared by coupling with graphene oxide (GO) with different mass fractions in a solvothermal reaction system. The microscopic morphology, crystal structure, and optical characteristics of the photocatalysts were characterized. The degradation of p-Nitrophenol (PNP) and polyacrylamide (PAM) by photocatalytic materials under simulated solar irradiation were studied, and the degradation kinetics were also investigated. The results showed that cubic Cu2O was modified by ZnO nanorods and distributed on rGO nanosheets. The ternary Cu2O/ZnO/rGO nanocomposites have stronger simulated solar absorption ability and higher photodegradation efficiency than pure ZnO and binary Cu2O/ZnO nanocomposites. When the amount of Cu2O/ZnO/rGO-10 was 0.3 g L−1, the degradation rate of 10 mg L−1 PNP reached 98% at 90 min and 99.6% of 100 mg L−1 PAM at 30 min. The photocatalytic degradation processes of PNP and PAM all followed the pseudo-first-order kinetic model. Free radical trapping experiments showed that superoxide radicals were the main active substances to improve photocatalytic efficiency. In addition, after four recycles, the catalytic efficiency of Cu2O/ZnO/rGO-10 was still over 90%. It showed that Cu2O/ZnO/rGO-10 was a promising catalyst for wastewater treatment because of its good photostability and reusability. [ABSTRACT FROM AUTHOR]

Understanding the fate of terrestrial organic carbon (terrOC) preservation in the marine environments is critical for deciphering the biogeochemical processes associated with the global carbon cycle and the Earth's climate change. The mechanisms controlling terrOC preservation are not completely understood, while lateral oxygen exposure time (OET) is considered as a critical controlling factor. Here, we first utilized molecular dynamics simulations to investigate the structural properties of lignin under anoxic, suboxic, and oxic conditions for understanding the mechanisms of terrOC preservation during sediment lateral transport in the ocean. Our finding suggested that oxygen exposure was indispensable for terrOC degradation through influencing the structural stability and reactivity of lignin. Our simulated results showed that in suboxic environments, prolonged OET may enhance terrOC preservation. Our organic geochemical results suggested that terrOC preferably preserved in coarse silts (20-63 μm) than fine silts (<20 μm) in suboxic environments, largely due to hydrodynamics-driven prolonged OET in coarse sediments, which may efficiently reduce CO 2 emissions. Overall, our study sheds new light on the mechanisms of lateral OETs on terrOC preservation in suboxic conditions and, from a unique molecular structural perspective, provides insights into the impact of prolonged OETs on terrOC oxidative degradation in the marine environment.