Study On Reaming Of Phenolic-based Carbon Beads And Degradation Of Phenol By Zero Valence Iron Carbon Beads

In this paper,phenolic carbon beads,zero-valent iron-carbon beads and nitrogen-doped zero-valent iron-carbon beads were prepared by alginic acid sol-gel assisted method with phenolic resin as carbon source.The pore expansion of phenolic based carbon beads was studied.The zero-valent iron-carbon beads and nitrogen-doped zero-valent iron-carbon beads were characterized by scanning electron microscope(SEM),energy dispersive spectrometer(EDS),X-ray diffraction(XRD)and nitrogen adsorption and desorption test(BET),and their phenol degradation ability was evaluated.The main results are as follows:(1)Phenolic carbon beads are mainly composed of amorphous carbon.5%potassium chloride is used as reaming agent,0.2M zinc nitrate is used as gel,the specific surface area of phenolic based carbon beads is 668.2m~2/g,and the hardness of the beads is 14.7N/bead.(2)The carbon elements in zero-valent iron-carbon beads mainly exist in the form of graphite carbon,and iron mainly exists in the form of zero-valent iron and iron carbide.There are three kinds of morphology in zero-valent iron-carbon beads:spherical agglomeration,rod-like and dispersed region.With the prolongation of gel time,the iron content of zero-valent iron-carbon particles increases,the specific surface area increases,and the average pore size decreases.The dispersion of zero-valent iron beads in gel particles for 24 hours is relatively good.When p H was 4,temperature was 60℃and the reaction time was 4 h,the degradation rate of phenol was 100%and the removal rate of COD was 78%.(3)Nitrogen doping does not cause the aggregation of zero-valent iron,the zero-valent iron in N-1%sample is well dispersed,and the surface of N-1%beads has obvious porous structure,and the iron content is relatively high.Compared with N-0%particles,the specific surface area of N-1%beads decreased,pore volume and average pore size increased,and when N-1%beads were used at 40℃for 15 min,the conversion of phenol reached 100%,and the removal rate of COD was 62%after 4hours.N-1%beads can maintain faster phenol degradation rate and higher COD removal rate at higher phenol concentration.