Study On Surface Modification Of Titanium And Filter Paper Substrates And Their Performances Of Separation And Adsorption

In this paper,using titanium wire mesh and filter paper as the basic materials,the mechanical stability and chemical stability of super-amphiphobic titanium mesh,as well as the self-cleaning application of super-amphiphobic titanium mesh and the application of oil-water micro-separation and oil-oil micro-separation are studied.Titanium wire with different surface wettability were used for in f in-tube solid-phase microextraction（SPME）.On-line enrichment and analysis of common environmental estrogens and polycyclic aromatic hydrocarbons in the environment samples were carried out with the help of an in-tube solid-phase microextraction device coupled with liquid chromatography.At the same time,the application of Ti O₂-modified superhydrophobic filter paper for emulsion separation,as well as the application of Janus filter paper for oil-water separation,unidirectional transport in air,and unidirectional transport between liquid-liquid interface are also studied.1 Super-amphiphobic surface with low surface robustness is not suitable for practical application due to its weak mechanical strength.In this work,an in-site synthesis of nanoscale flower-like Ti O₂on the surface of a titanium mesh was performed via a hydrothermal method using 20-m M hydrofluoric acid at 160°C for 8 h.After chemical modification with low-surface-energy heptadecafluoro-1,1,2,2-tetrahydrodecyl trichlorosilane,a super-amphiphobic coating was formed with excellent chemical and mechanical durability.After it was irradiated for8 h with ultraviolet light,it was used for oil/water and oil/oil mini-separations.This was attributed to its unidirectional penetration for liquid droplets having different surface tensions.A smart super-amphiphobic mesh with photochemical activity could potentially gate and sort liquids via surface tensions.2 Evaluation of the hydrophobic/hydrophilic interaction individually between the sorbent and target compounds in sample pretreatment is a big challenge.Herein,a smart titanium substrate with switchable surface wettability was fabricated and selected as the sorbent for the solution.The titanium wires and meshes were fabricated by simple hydrothermal etching and chemical modification so as to construct the superhydrophilic and superhydrophobic surfaces.The micro/nano hierarchical structures of the formed Ti O₂nanoparticles in situ on the surface of Ti substrates exhibited the switchable surface wettability.After UV irradiation about 15.5 h,the superhydrophobic substrates became superhydrophlic.The morphologies and element composition of the wires were observed by SEM,EDS and XRD,and their surface wettabilities were measured using the Ti mesh by contact angle goniometer.The pristine hydrophilic wire,the resulted superhydrophilic wire,superhydrophobic wire and the UV-irradiated superhydrophilic wire were filled into a stainless tube as the sorbent instead of the sample loop of a six-port for on line in-tube solid-phase microextraction,respectively.When employed in conjunction with HPLC,four kinds of wires were comparatively applied to extract six estrogens in water samples.The optimal conditions for the preconcentration and separation of target compounds were obtained with a sample volume of 60 m L,injection rate of 2 m L/min,a desorption time of 2 min,and a mobile phase of acetonile/water（47/53,v/v）.The results showed that both the superhydrophilic wire and UV-irradiated wire had the highest extraction efficiency to the polar compounds of estrogens with the enrichment factors in the range of 20-177,whilst the superhydrophobic wire exhibited the highest extraction efficiency to the non-polar compounds of five polycyclic aromatic hydrocarbons（PAHs）.It demonstrated that extraction efficiency was mainly dependent on the surface wettability of sorbent and the polarity of target compounds,which was in accordance with the molecular theory of Like Dissolves Like.3 Fiber fabrics with unidirectional liquid transport properties and emulsion separation properties have attracted extensive attention from the scientific and industrial communities.However,the pore size of the fiber fabric is an important factor to achieve unidirectional liquid transport and emulsion separation.Here,we prepared a suspension of titanium dioxide,silicon dioxide,tetraethyl silicate,perfluorooctyltrichlorosilane,etc.in absolute ethanol,and a series of superhydrophobic filter papers were fabricated by immersion method.It was attributed that titanium dioxide increased the roughness of the filter paper,and perfluorooctyltrichlorosilane chlorosilane reduced the surface energy of the filter paper,and the modified filter paper with less pore size was successfully used in emulsion separation.One side of the perforated superhydrophobic filter paper was irradiated with ultraviolet light to obtain Janus filter paper,which was successfully used for oil-water separation,unidirectional transport of water in air,and unidirectional transport of liquid droplet between liquid-liquid interfaces.