Adsorption-photocatalytic Degradation Of Low Concentration PPCPs Promoted By Graphene/TiO₂ Nanowires Hybrid Structure In Hydrogel

Pharmaceuticals and personal care products?PPCPs?as typical trace organic pollutants,have complex chemical structures,strong stability,and are difficult to decay naturally.Moreover,their efficient removal is a challenging subject because of the limitation of low concentration mass transfer resistance in the removal process.In this paper,TiO₂ nanowires?TiO₂NW?and graphene oxide?GO?nanoparticles prepared as precursors,in normal temperature,reduction method is used to optimize prefabricated graphene/TiO₂ nanowires?GNW?,prefabricated GNW was implanted into the graphene hydrogel at room temperature under common reduction.Using XRD,Raman,FE-SEM,TEM,UV-vis DRS,FT-IR,N₂ adsorption-stripping,XPS analysis test method of optimization under the condition of the preparation of rGO/GNW an phase microstructure of specific surface area of light absorption features and surface chemical states have been characterized.The results showed that a large number of TiO₂nanowires were interwoven on the ultrathin graphene nanosheets.GNW closely integrated with rGO ultrathin nanosheets by chemical bonds,and there are strong interactions.GNW hybrid structure to increase the disorder of rGO ultrathin nanosheets.Due to hybridization and reduction of reducing agents in the graphene gel process,oxygen vacancies?V_O?and Ti³⁺were successfully introduced into GNW and rGO/GNW,which reduced the band gap of rGO/GNW and significantly improved the light absorption performance of rGO/GNW.The adsorption-photocatalysis performance of rGO/GNW on ethenzamide was investigated under vacuum ultraviolet?VUV?,ultraviolet?UV?,simulated visible light and near-infrared light.The results showed that when the initial concentration of ethenzamide was 500ppb and the amount of catalyst was 10mg/150mL,the adsorption performance of rGO/GNW under VUV light was significantly improved compared with other samples,and the adsorption equilibrium reached to 21%,which was significantly higher than rGO/P25?15%?,rGO/NW?16%?,GNW?13%?,TiO₂NW?10%?and P25?8%?.The photocatalytic apparent rate constants were 2.20 times of GNW,4.09 times of rGO/P25 and 4.31 times of rGO/NW,respectively.Under UV light,the removal rate reached 99.0%in 120min,and the photocatalysis apparent rate constant was 2.06 times of GNW,3.34 times of rGO/P25 and 17.42 times of rGO/NW.The simulated visible and near-infrared light also showed superior adsorption-photocatalytic performance.After repeated use for three times,it still shows good adsorption-photocatalysis activity.It is a kind of adsorption-photocatalysis material with high efficiency,stability and full spectral response that can be used for the removal of analgesia with low concentration.GNW hybridization and the three-dimensional network structure of hydrogels play a vital role in the removal of low concentration analgesics.The GNW hybrid structure in the hydrogel played a vital role in overcoming the mass transfer resistance of low concentration PPCPs.The as-prepared rGO/GNW hydrogel exhibits significant potential for the removal of low concentration PPCPs in water.