In order to remove toxic graphene oxide (GO) from aqueous solution, attapulgite (ATP) was used as adsorbent to recycle it by adsorption. In this paper, the effects of different pH, adsorbent mass, GO concentration, time and temperature on the adsorption of GO by attapulgite were studied, and the adsorption performance and mechanism were further explored by XRD, AFM, XPS, FTIR, TEM and SEM tests. The results show that when T = 303 K, pH = 3, and the GO concentration is 100 mg/L in 50 mL of aqueous solution, the removal rate of GO by 40 mg of attapulgite reaches 92.83%, and the partition coefficient K_d reaches 16.31. The adsorption kinetics results showed that the adsorption equilibrium was reached at 2160 min, and the adsorption process could be described by the pseudo-second-order adsorption equation, indicating that the adsorption process was accompanied by chemical adsorption and physical adsorption. The isotherm and thermodynamic parameters show that the adsorption of GO by attapulgite is more consistent with the Langmuir isotherm model, and the reaction is a spontaneous endothermic process. The analysis shows that attapulgite is a good material for removing GO, which can provide a reference for the removal of GO in an aqueous environment.

Diatomite is a non-metallic mineral resource rich in SiO₂, which can be used to modify coastal cement soil. In order to explore the mechanical modification effect of diatomite on coastal cement soil at the age of 7 days, based on coastal cement soil with cement content of 5% (mass fraction), diatomite of 0%, 5%, 10%, 15% and 20% (mass fraction) was mixed for modification. Through the unconfined compressive strength test, the triaxial unconsolidated undrained test, backscattered electron imaging (BSE), and energy-dispersive spectroscopy (EDS) technology, the influence of diatomite content and confining pressure on the peak strength of modified coastal cement soil was explored. The empirical formula between the peak strength of the DE specimen and the content of diatomite and confining pressure was established by curve fitting, and the fitting effect was ideal. When diatomite was mixed with coastal cement soil, the optimal dosage of diatomite was 5% from the perspective of mechanical properties and economic benefits of the maximum growth rate of compression and shear. The unconfined compressive strength test showed that the peak strength and elastic modulus of the modified coastal cement soil with 5% diatomite content were 37% and 57% higher than those of cement soil, respectively. The triaxial unconsolidated undrained test showed that the internal friction angle of the modified coastal cement soil was stable at about 30°, and cohesion of DE-5, DE-10, DE-15, and DE-20 increased by 28%, 48%, 78%, and 97%, respectively, compared to cement soil. The microscopic test found that the pore distribution of modified coastal cement soil is closely related to the strength change. The results show that the addition of diatomite can effectively improve the mechanical properties of soil-cement.