The dynamic adsorption experiment was carried out with PRB composite granular filler(CGF)to investigate the dynamic adsorption laws of Cd2+and the main influencing factors.The geometric characteristics of CGF and pore structure evolution were explored with the help of visualization and pore network model(PNM),and the dynamic balance relationship between filler erosion and pore blockage was clarified.The results show that the equilibrium adsorption is the maximum at a pump speed of 10 r/min and a mass concentration of 50 mg/L,which reaches 1.81 mg/g.The pump speed has the most influence on the breakthrough curve,and low volume of flow is more favorable for Cd2+adsorption.The porosity increases by 7.79%,the fractal dimension decreases by up to 7.95%after adsorption,and the pore blockage has a significant impact on the fractal dimension.CGF erosion reduces the surface area and average equivalent diameter.However,the proportion of particle with sphericity in the range of 1.4 to 1.6 increases to 75.9%.The average coordination number decreases from 10.43 to 8.65 after adsorption,with a decrease of 17.07%.Meanwhile,the numbers of"sticks"and"spheres"involved in coordination decrease by 43.28%and 31.63%,respectively.The CGF erosion leads to pores blockage in the middle of the columns and reduces the connection between pores and throats.However,the pores are not"substantially"clogged,and the PNM still maintains satisfactory connectivity.
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