Preparation,Structure Regulation And Properties Of Activated Carbon From Taihu Blue Algae And Its Application In Dye Wastewater Treatment

In recent years,the world has witnessed the surge of population and the rapid development of society.As a consequence,the speed of energy consumption has soared along the time.The consumption of traditional energy is accompanied by a large amount of greenhouse gas emissions,such as carbon dioxide（CO₂）,methane（CH₄）,nitrogen oxides（NO_X）,etc.,which has greatly accelerated the rate of global warming.Hence,the phenomenon of cyanobacterial bloom appears successively around the world.Moreover,China’s per capita water resources are far lower than the world average,and the spatial and temporal distribution is extremely uneven.As the world’s largest industrial country,China faces the arduous task of wastewater treatment.Therefore,accelerating the process of wastewater treatment is the top priority in the comprehensive green transformation of economy and society.However,the current treatment of cyanobacteria in the Taihu Lake is still based on reduction and harmlessness,and there is no means of resource utilization of cyanobacteria.Therefore,in this paper,activated carbon and activated carbon-based catalysts were prepared from Taihu blue algae,which provided an effective solution for the resource utilization of cyanobacteria and the treatment of dye wastewater.In this paper,blue algae from Taihu Lake were used as raw materials to prepare activated carbon（ACB）and catalyst（ACK）,and blue algae were utilized and applied to dye wastewater treatment.An ACB with ultra-high specific surface area,rich pore structure and excellent adsorption performance was prepared by adjusting the preparation conditions.The key factors affecting its adsorption performance were clarified,and the adsorption mechanism of ACB-4-2-8 on dyes was elucidated by adsorption kinetics and thermodynamics.ACB was used as the carrier of the catalyst,and advanced oxidation technology was used to further degrade dye wastewater.In this study,the effects of activation temperature on the structure of ACK and the degradation performance of methylene blue were fully investigated.The repeated use of ACK was verified.The role of hydroxyl radicals in the degradation process was systematically studied,and the degradation mechanism of dyes by ACK-8-Fe was clarified.The following results were obtained:On the one hand,an activated carbon（ACB-4-2-8）with ultra-high specific surface area(2178.90 m² g^-1)and developed pore structure(1.01 cm³ g^-1)was prepared by adjusting the carbonization temperature,carbon-alkali ratio and activation temperature.Starting from the saturated adsorption capacity,the relationship between pore structure and saturated adsorption capacity was clarified,and the cyanobacteria-based activated carbon with the best adsorption performance was selected,and the maximum adsorption capacity was 1517 mg g^-1.In addition,the key factors affecting the adsorption performance of ACB-4-2-8 were systematically studied.The adsorption kinetics study showed that the pseudo-second-order kinetic model had good adaptability to the adsorption of methylene blue dye by ACB-4-2-8.Langmuir isothermal adsorption models were also used to explore the interaction between ACB-4-2-8 and dye molecules,which proved that the dye would cover the surface of ACB-4-2-8 with a monolayer.Through thermodynamic analysis,it was proved that the adsorption of methylene blue by ACB-4-2-8 was mainly physical adsorption.On the other hand,a high-performance Fenton-like catalyst ACK-8-Fe was developed based on ACB.The analysis of X-ray diffraction and X-ray photoelectron spectroscopy proved that the iron-based catalyst was successfully loaded and the main component of the iron-based catalyst was determined to beα-Fe₂O₃.The effects of key reaction parameters such as initial dye concentration,solution p H and catalytic reaction temperature on the degradation performance of ACK-8-Fe were systematically studied.The free radical quenching experiment and the EPR experiment proved that the hydroxyl radical was the main active free radical.The strong catalytic degradation performance of ACK-8-Fe is attributed to its large specific surface area and highα-Fe₂O₃ loading.Moreover,higher N content,especially pyrrole N content,and the presence of persistent free radicals in ACK-8-Fe can accelerate the Fe（III）/Fe（II）cycle and promote its catalytic performance.Through cyclic degradation,ACK-8-Fe exhibits good reusability and stability,which is crucial for practical applications.This paper confirms the feasibility of preparing biomass activated carbon and activated carbon-based catalyst from Taihu blue algae which provides a good solution for the resource utilization of Taihu blue algae.In addition,an activated carbon material with ultra-high specific surface area,developed pore structure and ultra-strong adsorption performance and a high-performance Fenton-like catalyst were developed,which has reference significance for solving wastewater problems in actual production and life.