Study and Characterization of Organically Modified Silica-Zirconia Anti-Graffiti Coatings Obtained by Sol-Gel

In this work, it is presented the synthesis and characterization of transparent and colorless organic-inorganic hybrid anti-graffiti protective materials obtained by sol-gel method. This type of materials is based on MTES （methyltriethoxysilane）, TPOZ （tetrapropoxide of zirconium） and PDMS （polydimethylsiloxane）. The synthesis has been carried out at 25, 35 and 45 ℃ in order to evaluate the role of temperature in the structure, microstructure and anti-graffiti behavior as well. The incorporation of zirconium within the organic modified silica network, of sols after being gelled and dried, is evident by a shoulder which increased with temperature situated at 950 cml （Si-O-Zr bonds）, and it is homogenously dispersed inside the matrix avoiding the formation of large ZrO2 precipitates. As the temperature increases, the hydrolysis and condensation reactions occur in more extension and thus, the obtained sols are more cross-linked and present more Si-O-Zr linkages. The promising anti-graffiti beha＇4ior of the protectNe hybrids was qualitatively determined being the spot removal higher than 90%.

Prevention and Control of Chlorella for C30 Concrete Surface with Coral Aggregate

C30 coral aggregate concrete with chlorella control effect was prepared by adding nano-TiO_(2) and hydrophobic material,and the effects of nano-TiO_(2) and hydrophobic material on the basic properties of C30 coral aggregate concrete and chlorella control effect under different experimental conditions were compared.The experimental results show that nano-TiO_(2) and hydrophobic materials have a certain degree of influence on the basic properties of concrete,but the influence is not significant.Under long-term immersion,nano-TiO_(2) and hydrophobic materials can inhibit the growth of Chlorella vulgaris.The maximum fluorescence value of concrete is decreased by 53.6% after adding TiO_(2),and the maximum fluorescence value of concrete is prolonged by 20%(1 day).The maximum fluorescence value of concrete is decreased by 67.7% after adding hydrophobic materials,and the maximum fluorescence value of concrete is also prolonged by 20%(1 day);Under the condition of simulated tidal water,the inhibition effect of Nano-TiO_(2) on the growth degree and growth rate of Chlorella vulgaris is weakened,at this time the maximum fluorescence value of concrete mixed with nano-TiO_(2) is decreased by 50.5%,and the maximum fluorescence value is only prolonged by 14.3%;while the inhibition of hydrophobic materials on the growth degree and growth rate of Chlorella vulgaris is enhanced significantly,and the maximum fluorescence value of concrete with hydrophobic materials is decreased by 80.3%;the maximum fluorescence time is prolonged by 114.3%.

Preparation and properties of a silver particle-coated and 1-dodecanethiol-modified superhydrophobic melamine sponge for oil/water separation

A Ag particle-coated and 1-dodecanethiolmodified melamine sponge(Ag-DDT-MS)was prepared through surface roughness by coating silver particles and subsequent grafting of a hydrophobic long hydrocarbon chain.Superhydrophobic and 3D porous Ag-DDT-MS was characterized by Fourier transform infrared spectroscopy,scanning electron microscope,energy-dispersive X-ray spectroscopy,and X-ray diffraction.The water contact angle of Ag-DDT-MS reached 159.2°.Ag-DDT-MS exhibited excellent absorption capacity for high viscous oils and organic solvents,ranging from 42.8 to 105.2 g∙g−1.The absorbed oils can be easily collected by the mechanical pressing process,and the oil recovery rate was satisfactory,more than 90%after 20 recycles.Ag-DDT-MS material also demonstrated good stability and excellent compressionrecovery ability,keeping 88.6%of the initial height after ten compression-release cycles.