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TiO2 sol was prepared by sol-gel method using tetrabutyl titanate as precursor and acetic acid as catalyst, and then hydrophobically modified TiO2 sol was obtained by reducing its surface energy with γ-methacryloxypropyl trimethoxysilane (KH570), the modified TiO2 sol was sprayed on the surface of the filter media to make it superhydrophobic. The wettability, surface morphology, chemical composition and filtration performance of the filter media before and after modification were analyzed.The results show that the modified coating is uniformly deposited on the surface of the filter media and the fiber surface completely wrapped, and the water contact angle of the modified filter media reaches 156.29°. By testing the filtration performance of the particles with the size of 0.3 μm at the filtration velocity of 0.043-0.127 m/s, it can be seen that the filtration efficiency of the modified filter media is increased by an average of 2.7672% compared with the unmodified filter media, and the filter quality factor is increased by 0.34%, which improves the filtration performance of the filter media. In addition, the hydrophobic filter media still has superhydrophobicity after 50 times of sandpaper abrasion cycles and 30 h acid-base solution immersion. The modified filter media has excellent self-cleaning performance by cleaning the surface of coal powder pollution.

In hot in-place recycled (HIR) technology, the in-place mixing paving construction method suffers from the problems of low mixing temperature and short mixing time, which lead to incomplete rejuvenator diffusion in waste asphalt binder. Quantitative evaluation of rejuvenator diffusion degree and the corresponding microscopic characteristics are beneficial in guiding HIR construction technology. In this study, the interface model of virgin asphalt, rejuvenator, and aged asphalt was established through molecular dynamics (MD) simulations. Rejuvenator diffusion rates at the virgin–aged asphalt interface (VAAI) at different temperatures were investigated. The results showed that temperature increased rejuvenator diffusion rate. Relative concentrations at different diffusion times were used to quantitatively evaluate rejuvenator diffusion degrees at the interface. The results showed that diffusion degree and uniformity of rejuvenators could be improved by the passage of time. At the same time, the modulus and stress–strain curves of various VAAI models with different diffusion degrees were drawn. The results showed that increase of diffusion degree increased modulus and maximum tensile stress and strain of VAAI; that is, stability at high temperature and crack resistance at low temperature were improved. At low rejuvenator diffusion degrees, rejuvenators accumulated at VAAI, which had a negative effect on reclaimed asphalt performance. According to MD simulation results and site conditions, it was suggested that the HIR technology construction temperature had to remain above 428 K. At the same time, it was suggested that rejuvenator diffusion degree had to be increased to improve road performance. [ABSTRACT FROM AUTHOR]

In order to solve the problem of blocking the filter media when bag filters are used to deal with high-humidity dust, hydrophobic surface-modified filter media were prepared. Here we constructed a multi-layer rough structure using TiO2 and SiO2, with polydimethylsiloxane (PDMS) subsequently deposited to reduce its surface energy to prepare stable and robust TiO2–SiO2@PDMS modified superhydrophobic filter media. Through modification of the filter media, its surface was changed from superhydrophilic to superhydrophobic, and the water contact angle reached 158°. For the particles with 0.3 μm, the filtration efficiency and quality factor of the modified filter media are higher than those of the unmodified filter media at a flow velocity of 0.043–0.127 m/s, which improves the filtration performance of the filter media. In addition, the modified filter media has strong durability in harsh environmental conditions (such as mechanical wear, strong acid or alkali solution), and has excellent self-cleaning performance. Therefore, such superhydrophobic filter media have great potential for the application of bag filters in various industrial production processes. Highlights: Superhydrophobic filter media is prepared by TiO2–SiO2@PDMS coating. The filtration efficiency and quality factor of the modified filter media are improved by 4.64% and 0.52% on average compared with the unmodified filter media. The filter media modified by TiO2–SiO2@PDMS has excellent stability and self-cleaning performance. [ABSTRACT FROM AUTHOR]