Fabrication Of Hierarchical Porous Carbon And Its Performance In The Adsorption Of Dye From Wastewater

With the development of industrial production,a large amount of dyes are discharged into the water body along with wastewater,which is harmful to the quality of the water body and the safety and health of human beings.Adsorption is one of the commonly used dye wastewater treatment technologies.The most commonly used adsorbent is activated carbon.Due to the single pore structure and a small pore size,and the adsorption effect on macromolecular dyes is not ideal.Therefore,in oder to improve the adsorption rate and capacity of bulky dyes in water and wastewater,this study proposed to design a novel carbon adsorbent containing hierarchical porous structure.The paper used double template carbonization to prepared hierarchical porous carbon.The characterization of hierarchical porous carbon was carried out by SEM,BET,TEM,XRD,etc.At the same time,the adsorption performance of dyes with different molecular sizes was studied,and the influence of influencing factors on the adsorption effect was investigated.This study found:(1)Hierarchical porous carbons(HPC)with interconnected macroporous and mesoporous structures was successfully prepared.The HPC has interconnected porous structure with large pores of 800-1000 nm diameter,through the inner window of 100nm size and the wonderful mesopores with an average diameter of 8.1 nm between the walls of the macropores.The prepared hierarchical porous carbon had a BET surface area of 1056 m~2/g and a pore volume of 2.16 cm~3/g.(2)For bulky molecular dyes(rhodamine B(RB)and bright yellow(BY)),the adsorption rate and adsorption capacity of HPC is greater than MC and AC.The intraparticle diffusion model fitting the adsorption kinetics found that for the adsorption of three dyes,the intraparticle diffusion rate of HPC remains 2-4 times that of AC and 1.5-2 times that of MC.(3)The adsorption capacity of the carbonaceous adsorbent largely depends on the molecular structure of the dye.For the adsorption of MB,the adsorption capacity of AC is significantly higher than that of HPC and MC,and commercial activated carbon(AC)and mesoporous carbon(MC).In contrast,HPC has excellent adsorption capacity for large volume dyes such as bright yellow(BY).The maximum adsorption capacity of the prepared HPC to BY reached 584.32 mg/g,which was almost 6 times that of AC.(4)The adsorption process of HPC to BY is a spontaneous endothermic process(△G<0),that is,increasing the ambient temperature is beneficial to the adsorption effect.The smaller the pH value,the larger the adsorption capacity of HPC adsorption BY;the appropriate increase of salt ion concentration in the solution will increase the adsorption capacity of HPC;...