The Treatment Of Organic Wastewater By Modified Waste Derived Carbon In Photothermal And Fenton-like Processes

With the intensification of resource shortage and environmental pollution,resource utilization of waste has become an urgent task,and how to effectively use waste is the focus of promoting the development of the circular economy.Because of the excellent light absorption,highly tunable structure,low cost,abundant sources,large specific surface area,and the presence of multiple functional groups on the surface,waste-derived carbon materials have been widely used in the treatment of toxic organic wastewater,such as catalysts for the solar interface water evaporation technology and advanced oxidation process.The solar interface water evaporation technology allows the resourcefulness of polluted water from which clean drinking water can be obtained.There is relatively little research on the use of carbon-based materials for water evaporation technology to reduce contaminants such as physicochemical in evaporated water.How to achieve efficient and safe wastewater resource recovery by regulating the microstructure of waste-derived carbon is one of the important scientific issues based on waste-derived carbon in the application of photothermal water evaporation technology.Meanwhile,waste-derived carbon has received increasing attention in the advanced oxidation process based on persulfate.How to solve the challenges such as low catalytic efficiency and poor stability of waste-derived carbon by modifying it is still one of the main focuses of current research.Therefore,in this paper,two carbon-based materials were prepared with different wastes as precursors for the photothermal resource recovery and advanced oxidation treatment of organic wastewater,with the modification of waste carbon and its application in wastewater treatment as the theme.The main studies obtained are as follows:(1)Waste leaves were used as precursors to prepare biochar from leaves(BC),and the relative content of sp2-hybridized carbon in BC was regulated.The influence mechanism of sp2-hybridized carbon in BC on the solar-powered recycling performance of organic wastewater was explored.The relative content of sp2-hybridized carbon in BC was adjusted by controlling different pyrolysis temperatures,which accelerated electron transition and inhibited photogenic electron and photogenic hole recombination,so as to improve the photothermal conversion performance of biochar.BC with high graphitized carbon content can inhibit the recombination of photogenerated electrons and photogenerated holes,and has better light absorption performance in the near infrared spectrum.The solar evaporation efficiency of BC-800 is as high as 65.64% and the evaporation rate is 1.32 kg·m-2·h-1 under the light of 1.37 suns.In addition,the removal rate of metal ions in the photothermal process of BC-800 can reach 99.00%,which can effectively reduce the plasma concentrations of Na+,Mg2+,K+ and Ca2+ in water.At the same time,the concentrations of chemical oxygen demand,ammonia nitrogen and total nitrogen in the toxic organic wastewater treated by BC-800/solar-powered water evaporation decreased significantly.(2)A nitrogen-containing carbon-based catalyst(SNBC5)prepared using waste masks as precursors was used to activate persulfate(PS)for efficient treatment of toxic organics in wastewater while achieving resource utilization of waste masks.The experiments showed that SNBC5 had efficient activation performance for PS,and could degrade 98% of bisphenol AF(BPAF)within 5 min with a reaction rate as high as 0.01424 s-1.In addition,SNBC5 still had good degradation performance after 10 times of recycling,and its structure did not change significantly.The characterization and experiments showed that graphite nitrogen and surface C=O functional groups as active sites were conducive to the production of the main active oxygen species 1O2.In addition,the pyridine nitrogen site promoted the production of SO4·-and participated in the removal process of BPAF.