The Application Of Interfacial Engineered Functional Oxide-based Materials In Adsorption And Detection Of Environmental Pollutants

With the rapid development of the global economy,the water resources that human beings depend on are facing serious pollution and depletion threats.There is no doubt that the release of various pollutants is seriously threaten to the public health and ecological system.Therefore,the effective elimination and rapid dectection of pollutants from surface water such as industrial wastewater and domestic sewage are of great significance for maintaining the safety of the aqueous environment.The interfacial engineered functionalized nanomaterials provide new opportunities for water environment remediation.The solid/liquid interface properties can be purposefully designed by exfoliating 3D materials into 2D materials,adjusting specific surface area and pore structure,or grafting organic groups on the surface which can affect the physical adsorption and chemical reaction process of pollutants on the limited interface.Therefore,this paper focused on the designing of interface properties between solid materials and solutes.Serial advanced functional oxide-based materials for the effective enrichment of various pollutants and in-situ detection.The specific research contents are as follows:(1)The synthesis of hollow sphered layered double hydroxides(LDHs/HCMSs)and the mutual elimination of Pb(Ⅱ)and humic acid(HA).Considering that the higher specific surface area is conducive to the adequate exposure of active sites,the application of hollow sphered LDH(LDHs/HCMSs)for mutual removal of heavy metal ions and natural organic matter were investigated.Firstly,carbon microspheres were selected as a template for in-situ growth of 2D LDH.Then,hollow sphered LDH was obtained by temperature programming.The unique hollow sphered structure and high specific surface area(～231 m2 g-1)ensured the fluent mass transport,and provided abandunt adsorption sites in surface interface.In this work,the typical heavy metal ions Pb(Ⅱ)and natural organic HA were selected as research objects to investigate the mutual removal process onto LDHs/HCMSs.The results indicated that the coexistent Pb(Ⅱ)or HA could improve the adsorption of single pollutant.Further characterizations demonstrated that the mechanism of Pb(Ⅱ)/HA adsorption onto LDHs/HCMSs was attributed to the abundant binding sites for pollutants and the formation of ternary HA-Pb-LDHs/HCMSs complex,which enhanced co-removal performance.(2)The synthesis of MOF derived porous alumina microspheres(P-Al2O3)and its efficient elimination of U(Ⅵ)and Eu(Ⅲ).The previous work improved the specific surface area of oxides by using hard template method,but the pre-synthesis of the template was complicated.In order to solve this problem,a two-step synthesis of MOFderived P-Al2O3 was designed.The organic ligands of MIL-53(Al)were decomposed by precise temperature programming.The generated gas molecules created permanent porosity,further increasing the specific surface area.Serial characterization indicated that numerous micropores and mesopores existed in P-Al2O3 could provide more adsorption sites for U(Ⅵ)and Eu(Ⅲ).Compared with commercial γ-Al2O3,P-Al2O3 possessed higher specific area(～248.57 m2·g-1),and more excellent kinetics.The maximum adsorption capacities of U(Ⅵ)and Eu(Ⅲ)onto P-Al2O3 were 316.87 mg·g-1 and 223.37 mg·g-1,respectively,which was much higher than γ-Al2O3 and other functional metal oxides.The XPS analysis proved that the main mechanism was the complexation between U(Ⅵ)/Eu(Ⅲ)and P-Al2O3.This study further expands the broad application prospects of mesoporous oxide adsorbents in the treatment of radionuclide wastewater.(3)Enhanced U(Ⅵ)elimination of polyethyleneimine-functionalized carbon quantum dots(PECQDs)-magnetic MnFe2O4 composite.In order to improve the adsorption ability of MnFe2O4,PECQDs was applied to modify MnFe2O4 with surface interfaced functionalization.MnFe2O4-based material exhibited excellent removal efficiency and magnetic separation ability towards U(Ⅵ).Compared with CQDs modified MnFe2O4,the introduction of amino-groups enhanced the surface bonding effect between CQDs and MnFe2O4,which further improved the stability and removal efficiency during U(Ⅵ)elimination.The maximum adsorption of U(Ⅵ)onto PECQDs/MnFe2O4 achieved 194 mg·g-1 at 293 K.The results of thermodynamic study indicated that the endothermic reaction was dominated by spontaneous multilayered adsorption.Combined with characterization and experimental results,the surface complexation between abundant functional groups on PECQDs/MnFe2O4 and U(Ⅵ)was the main reason for the enhanced adsorption process.(4)Surface enhanced FRET for sensitive and selective detection of doxycycline(DOC)using surface interfaced functionalized organosilicon nanodots.The fluorescence detection of tetracycline antibiotics is mostly based on the mechanism of fluorescence quenching,or using the antenna effect of noble elements to achieve.To solve this problem and to achieve ratiometric fluorescence detection of DOC,electronrich aniline groups were grafted on the surface of silicone quantum dots.The abundant aniline functional groups on the surface interface fix the DOC in the limited surface space through π-π stacking.The conformation of DOC was changed and the green fluorescence was enhanced.Moreover,the spatial proximity and the matching of interfacial energy levels between OSiNDs and DOC enhanced the green fluorescence,which was attributed to the energy transport via fluorescence resonance energy transfer(FRET)from OSiNDs to DOC.The ratiometric fluorescence detection displayed a good linear range for DOC in the range of 1～35 mM with an excellent limit detection of～81 nM.Finally,the fluorescence of OSiNDs loading changed from blue to green with the increase of DOC concentration,and the in situ semi-quantitative detection of DOC was achieved.In summary,this paper is devoted to the development of new functionalized oxides for water remediation based on interface engineering,and to explore and optimize the physicochemical properties of materials for the efficiently removal or selectively detection of various pollutants.Combined with experiments and advanced characterization techniques,the mechanism of the reaction process has been verified and revealed,which has opened up horizons for the field of water environment purification and real-time monitoring.