Impact of H_(2)S on Hg^(0)capture performance over nitrogen-doped carbon microsphere sorbent:experimental and theoretical insights

A nitrogen-doped carbon microsphere sorbent with a hierarchical porous structure was synthesized via aggregation-hydrothermal carbonization.The Hg^(0)adsorption performance of the nitrogen-doped carbon microsphere sorbent was tested and compared with that of the coconut shell activated carbon prepared in the laboratory.The effect of H_(2)S on Hg^(0)adsorption was also investigated.The nitrogen-doped carbon microsphere sorbent exhibited superior mercury removal performance compared with that of coconut shell activated carbon.In the absence of H_(2)S at a low temperature(≤100℃),the Hg^(0)removal efficiency of the nitrogen-doped carbon microsphere sorbent exceeded 90%.This value is significantly higher than that of coconut shell activated carbon,which is approximately 45%.H_(2)S significantly enhanced the Hg^(0)removal performance of the nitrogen-doped carbon microsphere sorbent at higher temperatures(100–180℃).The hierarchical porous structure facilitated the diffusion and adsorption of H_(2)S and Hg^(0),while the nitrogen-containing active sites significantly improved the adsorption and dissociation capabilities of H_(2)S,contributing to the generation of more active sulfur species on the surface of the nitrogen-doped carbon microsphere sorbent.The formation of active sulfur species and HgS on the sorbent surface was further confirmed using X-ray photoelectron spectroscopy and Hg^(0)temperature-programmed desorption tests.Density functional theory was employed to elucidate the adsorption and transformation of Hg^(0)on the sorbent surface.H_(2)S adsorbed and dissociated on the sorbent surface,generating active sulfur species that reacted with gaseous Hg^(0)to form HgS.

Simulation and structural parameter optimization of rotary blade cutting soil based on SPH method

Pre-sowing mechanical tillage in crop fields is a primary task and important aspect of crop production.The interaction between the tillage components and the soil plays a crucial role in determining the energy consumption of tillage machinery.Therefore,it is essential to investigate soil-tool interaction mechanisms and optimize tool design for energy savings in soil cutting.The study employed the Smoothed Particle Hydrodynamics(SPH)method to investigate the soil cutting process of a typical rotary blade.The article describes the principles and modeling process of the SPH method in detail.It includes the selection of constitutive models,boundary treatments,and particle conversion.A high-precision soil-tool interaction model was established to analyze the deformation zone of the soil,cutting energy,cutting resistance,and soil particle movement.Orthogonal simulation experiments and response surface methodology were used to optimize key design parameters of the rotary blade considering both the reduction in cutting power consumption and the impact on the structural performance of the tool.The optimal parameters were determined as follows:a bending point included angle of 30°,a side cutting edge bending line direction angle of 51°,and a bending angle of 120°.These parameters resulted in a minimum power consumption of 0.181 kW while meeting the required structural performance.Finally,experiments were conducted on field rotary tillage,and the measured power consumption showed a deviation of 7.1%from the simulated power consumption.The optimized power consumption was reduced by 9.52%compared to the initial power consumption,validating the accuracy of the simulation process and the effectiveness of energy savings.