Persulfate/Dissolved Oxygen Triggered By Ordered Regulation Of Biochar Surface To Drive The Cleavage Of Contaminants In Water

Persistent organic pollutants,endocrine disruptors,antibiotics,microplastics and other emerging contaminants（ECs）pose a great risk to the ecological environment and human health due to their biological toxicity,environmental persistence,bioaccumulation and other characteristics,and traditional water treatment methods are not effective in removing them.Advanced oxidation processes（AOPs）,which are based on the generation of strong oxidizing radicals,are recognized as promising technologies for ECs removal.However,to reduce the level of ECs in the aqueous environment below a safe threshold,it is inevitable to add excessive additional energy and resources,which not only results in large carbon emissions but also leads to high water treatment costs.In China’s latest release of the"14th Five-Year Plan"energy conservation and emission reduction work program clearly pointed out to"promote the comprehensive utilization of straw and resource utilization of livestock and poultry manure"and is expected to"reduce carbon dioxide emissions by 18%,the total emissions of major pollutants continue to reduce,and the ecological environment continues to improve"by 2035.To solve the bottleneck problem of high energy consumption in the water purification process and respond the 14th Five-Year Plan to help reduce carbon emissions and improve the water environment,this paper converts rural waste resourcing into an efficient water treatment catalyst based on the double reaction center（DRC）Fenton-like reaction mechanism,which simultaneously solves the problems of difficult rural waste resourceization and high cost of water purification process,with the following main research:（1）Rural waste chicken manure（CM）was used as a raw material for the synthesis of resourcelized CM nanosheets（RCM NSs）,using a programmed warming method.The structures of the Ca CO₃ and graphene-like phases in the catalysts were determined by a series of characterization tools,which confirmed the formation of cation-πstructures（C-O-Ca bond bridges）between Ca CO₃ and graphene-like structures,thus inducing the electron polarization distribution on the catalyst surfaces.The construction of this surface structure allowed the complete removal of many ECs in a relatively short time,such as bisphenol A（BPA）,ciprofloxacin（CIP）and2-chlorophenol（2-CP）in the RCM NSs/PMS system all achieved complete removal in 30 min,and have good adaptability in a wide p H range and saline solution.In fixed bed experiments,the RCM NSs/PMS system was able to maintain the removal of more than 90%of the contaminants after 1735 hours of operation.The mechanism studies showed that the electron-donating effect of contaminants in the electron-poor microregions can be triggered by using just a trace amount of PMS,so that the contaminants can be directly oxidized and decomposed.While PMS is activated to¹O₂,dissolved oxygen（DO）is activated to ¹O₂ and O₂^·–in the electron-rich microregion on the catalyst surface to attack the contaminants.（2）In order to further enhance the electron polarization distribution on the catalyst surface to make full use of the endogenous substances in the wastewater,the ordered surface modulation of rural waste straw（WS）biochar was achieved by using in situ synthesis to synthesize cobalt-doped porous honeycomb straw biochar（h-Co-WS）.Techniques such as XPS and Raman reveal the formation of enhanced C-O-Co bond bridges between cobalt oxides and graphene-like C（π）,where electrons on the largeπbonds are deflected and pooled toward the cobalt atoms through the C-O-Co bond bridge,which in turn leads to the formation of electron-rich cobalt centers and electron-deficient centers on the aromatic-like rings of C（π）.The contaminants and C（π）carry outπ-πstacking to promote the electron donating effect of the contaminants,which makes the contaminants achieve surface self-cracking and rapid migration of electrons through the strong Co-πinteraction at the interface.With DO in water as the electron acceptor,the h-Co-WS water self-purification system can achieve efficient and long-term stable removal of ECs without the addition of additional energy/oxidant.