Preparation And Application Of Sargassum Fusiforme Based Mesoporous Activated Carbon

Mesoporous activated carbon is a kind of adsorbent with high specific surface area and high mesoporosity.The traditional methods for preparation of mesoporous activated carbon include the chemical,catalytic and templated methods.In this paper,by using the waste of Sargassum fusiforme as a raw material,mesoporous activated carbon with excellent performance was prepared via CO₂ physical activation.Firstly,the effect of activated temperature,activated time,and CO₂ flow rate on the specific surface area,total pore volume and burn off of activated carbon was investigated,the experimental factors and levels were thus determined.The response surface methodology was used to optimize the process parameters in lab scale.The pilot-plant production of activated carbon was also investigated and piolt-plant test procedure was obtained.The prepared product was applied to remove Congo red in simulated wastewater,and the effect of experimental parameters on the adsorption process was investigated by static adsorption tests.The kinetics analysis of the removal process was carried out.Then the dynamic adsorption experiments was carried out,and the influence of different factors on the breakthrough curve was investigated.The adsorption process was fitted by the BDST and Thomas models.The results indicated that:?1?Under the optimal conditions of activated temperature 900�C,activated time 30min,and CO₂ flow rate 1.8 L�min^-1,activated carbon with the specific surface area of1329 m²�g^-1,and value of methylene blue of 235 mg�g^-1 was obtained.The pore volume and mesoporosity were 1.1769 mL�g^-1and 65%,respectively,while the pore diameter was concentrated around 4 nm.?2?Pilot-plant test showed that the optimal conditions for the production of activated carbon were as follows:activated temperature 900�C,feedstock 4.5 kg�h^-1,CO₂ flow rate 25 L�min^-1,feedstock rotation rate 15 rpm,and furnace rotation rate 30rpm.The value of methylene blue of the prepared activated carbon was in the range of255-300 mg�g^-1.The main performance indicators of the product reaches the first-grade quality standards of GB?T/13803.2-1999?,which was superior to the activated carbon products prepared on lab scale.?3?The results of adsorption test indicated that the adsorption capacity of Congo red for Sargassum fusiforme based mesoporous activated carbon was better than other adsorbents,indicating the prepared activated carbon was suitable for the adsorption of macromolecules?such as Congo red?in dye wastewater.?4?The rapid reaction stage of activated carbon for different concentrations of Congo red solution meet well with the pseudo-second-order kinetic model,and its correlation coefficient ranged from 0.9979-0.9999,indicating that the adsorption is dominated by chemical adsorption.?5?The correlation coefficients of BDST and Thomas model fitting curve were R²>0.99,0.85,respectively,indicating that both of them could apply to the adsorption of Congo red by activated carbon in the fixed bed.By using the waste of Sargassum fusiforme as a raw material,mesoporous activated carbon with excellent performance was prepared via physical activation.It had advantages,such as less pollution,simple process and low equipment requirements.It realized the effective utilization of the biomass resources of the Sargassum fusiforme,and provided a new material for removing macromolecules in the dye wastewater effectivly.It had good environmental and social economic benefits.