Design And Synthesis Of Aluminum-doped Carbon Matrix Composites For Tetracycline Removal

The potential harm to ecosystem function and human health from incomplete metabolism and bioaccumulation of antibiotics is of great concern.Tetracycline（TC）has been widely detected in aquatic environments around the world.Adsorption is one of the most effective strategies for alleviating tetracycline pollution in water.The rational design of high-performance adsorbents is challenging,especially the preparation of adsorbents with abundant pore structures,high active site distribution,and easily tunable functional groups through facile strategies.The regeneration step of the adsorption strategy usually adopts the alkaline elution method,and the contaminants are only desorbed from the surface of the material but not completely removed.Adsorbents using structurally stable filter paper as carbon precursors,adsorbents prepared by self-propagating combustion methods,and strategies to regenerate materials using degradation methods have not been reported.Therefore,this thesis conducts the following research:Three-dimensional copper-aluminum bifunctional fiber composites（3D-Cu/Al-FC）were successfully prepared by simple calcination using filter paper as carbon precursor for the removal of TC in water.The adsorption capacity of the 3D-Cu/Al-FC were studied by using characterizations and adsorption experiment tests.The experimental results show that the pseudo-second-order kinetic and Langmuir model described the adsorption process well,and the maximum adsorption amount is 2391.78 mg/g.The removal rate of TC is 98.7%,and the adsorption removal rate of norfloxacin（NOR）,sulfamethoxazole（SMX）,and ciprofloxacin（CIP）is only 5.8%,2.1%,and 1.8%.3D-Cu/Al-FC has good anti-interference ability to various coexisting ions and humic acids.The material regeneration adopts the degradation method,TC is effectively decomposed into CO₂ and H₂O,and the high TC removal rate（89.12%）is still maintained after5 cycles.Electrostatic interactions,complexation and hydrogen bonding are the main adsorption mechanisms.Through the research work in this part,the potential of Al-doped carbon-based materials in the field of adsorption and the good prospect of the combination strategy of adsorption regeneration and degradation are confirmed.A novel three-dimensional porous Co₂C-doped Co Al₂O4 fiber composites（3D-CA-FC）were successfully prepared by simple calcination using filter paper as carbon precursor for the removal of TC in water.The adsorption and degradation properties were analyzed through a series of characterization and batch adsorption experiments.The adsorption process of TC can be described by pseudo-second-order kinetics and Langmuir isotherm model,and the maximum adsorption capacity reaches 1889.63 mg/g under neutral conditions.The adsorption capacity of 3D-CA-FC for TC is further improved in the presence of humic acid,CO₃^2-and weak alkaline environment.Under the optimum conditions,the degradation rate reaches 100%within 1 h.3D-CA-FC could effectively adsorb TC even in soulution containing coexistence of ions and humic acid（0-10 mg/L）.Pore filling,hydrogen bonding and complexation are the main adsorption mechanisms.¹O₂ is the main active infactors in the degradation process,while SO₄^·-and·OH also serves as part contributions.This part of the research work provides some inspiration for the construction of new bifunctional materials to remove organic pollutants by combining adsorption and degradation.Robust porous Zn/Al layered double hydroxide-doped spinel materials（Zn/Al-LS）were successfully prepared by simple calcination using filter paper as carbon precursor for the removal of TC in water.Batch adsorption experiments show that Zn/Al-LS has excellent adsorption performance,which is 2.4 times that of the original filter paper.All datas fit better with pseudo-second-order and Langmuir model,and the calculated maximum amount of Zn/Al-LS is 1995.66 mg/g and 2404.04 mg/g in p H 6.5 and 8.0 system respectively.Zn/Al-LS has good anti-interference ability to various coexisting ions and humic acid.The TC adsorbed on the material is decomposed by the degradation method,and a good regeneration effect is achieved.Electrostatic interactions,pore filling,and complexation are the main adsorption mechanisms.TC dissolved in water is colorless,and the white Zn/Al-LS adsorbed TC gradually turned bright yellow,which provides the possibility for the visualization of the adsorption process as well as the degradation-regeneration process.A series of Zn/Al N-doped carbon nanocomposites（Zn/Al-NCs）were prepared by self-propagating combustion technology for the removal of TC in water.According to a series of detailed characterization results,it is found that the morphologies of the synthesized materials at 90 ^oC,130 ^oC,and 180 ^oC are honeycomb-like structure,petal-like layered structure,and bubble structure with abundant mesopores and macropores,respectively.All adsorption datas fit better with pseudo-second-order and Langmuir model,and indicating that the adsorption process is monolayer chemisorption.All Zn/Al-NCs exhibit excellent adsorption performance for TC（>336 mg/g）and good anti-interference ability to various coexisting ions and humic acids.The adsorption mechanisms are pore filling,electrostatic interactions,complexation and hydrogen bonding.This part of the research work provides new ideas for exploring energy-saving,environmental protection,and time-saving strategies to prepare high-efficiency materials to remove water pollutants.