The Research On Efficient Removeal Of Smx By Microalgae Biochar Activated Peroxydisulfate

Spirulina biomass contains many valuable compounds,among which phycocyanin is a kind of high-nutrient protein with various medicinal and edible values,and widely welcomed in food science and medicine.However,a medium containing a large amount of inorganic salts must be used to extract algal blue protein from spirulina,which introduced a large amount of inorganic salts prevented spirulina from being directly used as animal feed or fertilizer and leading to a high downstream processing cost of spirulina.Therefore,it is an economical and feasible treatment method to convert it into low-cost,environmentally friendly biochar materials for sewage treatment.In this study,biochar was manufactured from C-phycocyanin extracted?C-CP?Spirulina residue?SDBC?via thermal pyrolysis.Simultaneously,N-doping was also achieved from the protein in the algae for obtaining a high-performance carbon catalyst for peroxydisulfate?PDS?activation.The results of elemental analysis,BET,XRD,XPS and FTIR showed that SDBC has large specific surface area,good nitrogen doping and conductivity and the highest specific surface area of SDBC900-acid is 370.1 m²/g.The results of oxidation degradation experiment revealed that SDBC/PDS system has good oxidation efficiency for micro-pollutants,and the pollutants can be completely removed in 20-45 minutes.In addition,the effects of SDBC concentration,oxidant concentration,pH,temperature,inorganic anions on SDBC/PDS system were investigated.The results showed that the concentration of PDS had little effect on the reaction system,while the dosage of SDBC had a great influence on the reaction system and SMX could degrade completely within 50minutes under the condition of SDBC 0.5 g/L.Moreover,the system was little affected by environmental temperature,pH and inorganic anions,thus has good application prospects.An in-depth mechanistic study was performed by integrating selective radical scavenging,solvent exchange?H₂O to D₂O?,diverse organic probes,and electrochemical measurement,unveiling that SDBC/PDS did not rely on free radicals or singlet oxygen but a nonradical pathway.PDS intimately was bonded with a biochar?SDBC 900-acid,pyrolysis at 900?C?to form a surface reactive complex that subsequently attacked an organic sulfamethoxazole?SMX?adsorbed on the biochar via an electron-transfer regime.During this process,the SDBC900-acid played versatile roles in PDS activation,organic accumulation and mediating the electron shuttle from SMX to PDS.More importantly,the nonradical species in SDBC 900-acid/PDS system were capable of inactivating the bacteria?Escherichia coli?in wastewater.After 90 minutes of reaction,the ratio of live/dead cells decreased to 7/93.The feasibility of SDBC in practical application was investigated by exploring its activation performance and calculating its preparation cost.The results show that the activation properties of SDBC can be restored by heat treatment,and it still has a high activation effect on PDS under complex water background and long-term continuous operation.In addition,the cost of SDBC is much lower than that of activated carbon.SDBC can be used as PDS activator in practical engineering.