In this paper, a novel sulfonic acid-functionalized carbon/loess composite was prepared using sucrose as carbon source and loess as raw material. The characterization results shown that plenty of carbon particles distribute on the surface of the composite, and an abundant of SO3H groups were successfully introduced onto the surface of the prepared composite through incomplete carbonization of sucrose and sulfonation of carbon particles. The adsorption capacity of the prepared composite for typical heavy metal ions also was investigated and compared with activated carbon, the results show that the composite shows excellent adsorprion performance, and the adsorption capacity for Fe3+, Pb2+, Cu2+, Cd2+, Ni2+can reach about 412%, 249%, 153%, 134% and 120% of the capacity of activated carbon, respectively. The prepared composite with excellent adsorption performance could be used as a low-cost alternative to activated carbon for the removal of heavy metal ions from wastewater.
In order to improve the oxidation resistance property of carbon/carbon composites, the C/C matrix was modified with a borate sol precursor and B4C micro-powders by a sol-gel integrating with a solvothermal process. The phase compositions, surface and cross-section microstructures of the C/C matrix modified by different B4C content were particularly investigated. Results show that the surface of the modified composites is covered by a coating composed of B2O3 and B4C, meanwhile, the internal micro-holes of the C/C composites are occupied by B2O3 and B4C. After oxidation in air at 973 K, the B2O3 glassy phase, due to the oxidation of B4C, seals the cracks and holes and effectively prevents C/C composites from oxidation. The weight loss of the modified C/C composites is only 2.21 % after oxidation in air at 973 K for 20 h.
Aiming at the impact failure of debris flow grille dam, considering the interaction of boulder-debris flow slurry- grille dam based on SPH-FEM, this article analyzed the variation laws of velocity, impact force and support reaction before and after debris flow slurry and boulders passing through grille dam. The results show that: SPH-FEM coupling method can truly reappear the impact of debris flow on the grille dam; the velocity of debris flow slurry and boulder are reduced by nearly 60% after passing through the dam, and the effect is remarkable; debris flow slurry and boulder have secondary impact on the grille dam. In the first impact, the greater the radius of the boulder, the greater the impact force; in the second impact, the impact force has nothing to do with the radius of the boulder.
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