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In order to study the mechanical properties and micro-mechanism of industrial waste fly ash-reinforced cement calcareous sand (FCS), the triaxial unconsolidated undrained (UU) test and scanning electron microscope tests (SEM) were carried out on it. The results of UU test show that the peak stress and energy dissipation of the FCS sample first increase and then decrease with the increase in fly ash content. Fly ash enhances the cement calcareous sand by increasing both the cohesion and internal friction angle, and adding 10% content of fly ash gives the largest values. The SEM test results shows that the hydration products of cement and fly ash filled the pores and cracks on the surface of the calcareous sand, which increased the compactness and structure of the FCS samples. The porosity of cement calcareous sand can be reduced from 27.6% to 12.8% by adding 10% fly ash. A brittleness evaluation index based on energy dissipation is proposed to quantitatively characterize the brittleness of FCS samples. The results show that when the content of fly ash is 5%, the brittleness of FCS samples is the lowest. This study shows that the mechanical properties of cement calcareous sand can be effectively enhanced by adding the appropriate amount of fly ash.

To remove graphene oxide contaminant from aqueous solution, laterite was used as an adsorbent to conduct batch adsorption experiments on graphene oxide aqueous solutions. The effects of pH, adsorbent mass, graphene oxide initial concentration, contact time, and temperature on graphene oxide adsorption by laterite were studied predominantly. The results show that graphene oxide adsorption by laterite strongly depends on pH, the kinetic data conforms to the second-order kinetic model, and the isotherm data are in line with Langmuir and Freundlich models. Moreover, temperature increment is more conducive to improving the adsorption capacity. Combined with scanning electron microscopy, transmission electron microscopy, atomic force microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and Raman microscopic tests, the internal changes of samples before and after adsorption were further revealed. The comprehensive analysis of the above experimental results shows that laterite is a good material, which can effectively remove graphene oxide contamination from aqueous solutions.