Ceramic membranes ultrafiltration (UF) has emerged as a promising alternative to the conventional clarification technology in sugarcane juice clarification industries, given their efficient and eco-friendly separation processes based on the size sieving effect. However, the upscaling application of ceramic UF membranes is still limited by their low permeate flux, high energy consumption and severe membrane fouling. Herein, to utilize the interactions at the interfaces, tubular SiC microfiltration (MF) membranes with special surface wettability were deliberately tailored through a novel penetration pressure counter-balanced crossflow method using 1H, 1H, 2H, 2H-perfluorooctyltrichlorosilane as a hydrophobic agent. The effect of an out-layer pressures (0-4.0 kPa) and flow rate (1.4-2.4 mL·s -1 ) on surface wettability of membranes were studied, and those obtained membranes were applied in sugarcane juice clarification. The wettability, functional groups, binding energy, chemical compositions, and microstructure of modified SiC membranes were analyzed to elucidate their wettability-performance relationships. The performance of modified SiC MF membranes in sugarcane juice clarification were mainly evaluated by the flux decline profiles and permeate solution turbidity. The SiC membrane with hydrophobic inner wall (WCA=142°) and hydrophilic outer surface (WCA=0°) were achieved at out-layer pressure of 2.0 kPa and flow rate of 1.9 mL·s -1 . The results show that the SiC membrane with such asymmetric wettability exhibited ultra-high stable permeate flux (844 L·m -2 ·h -1 ·bar -1 ), satisfactory turbidity reduction rate (95.7%), and relatively low flux decreased rate (64.4%). The improved antifouling performance can be primarily attributed to the hydrophobic inner wall, and negatively charged pore wall. This work primarily demonstrates the application potential of ceramic MF membranes with asymmetric wettability for the effective sugarcane juice clarification.
Hydrophobized soils (or so-called artificial hydrophobic soils) are a novel geomaterial with a great potential in engineering applications due to its low affinity to water. For saline soils, hydrophobizing such soils can mitigate the soil salinization and subsequent engineering disasters such as salt expansion and corrosion by chlorides. To induce soil hydrophobicity , hydrophobic agents are widely used such as organo-silanes, fatty acids, and waxes. Correspondingly, the engineering properties and durability of these hydrophobized soils have been comprehensively investigated. However, all these studies focused on the clean mineral soils, i.e. , the soils without salts and in a moderate pH. For saline soils, the feasibility, stability and durability of these hydrophobic agents are unclear. This paper aims to propose suitable and feasible hydrophobic agents in hydrophobizing saline soils, by investigating its hydrophobicity change and having an insight into the mechanisms. The saline soils used were collected from Qinghai, China, and were treated by five different hydrophobic agents at different concentrations, with the hydrophobicity quantified by water drop penetration time, surface tension and contact angle. The soil hydrophobicity change was recorded after the treatment and wetting-drying cycles, in order to assess its stability and durability. Fourier transform infrared spectroscopy (FTIR), Raman spectrum and N 2 adsorption experiment were carried out to study the mechanism of soil hydrophobicity formation and degradation. The results showed two agents, namely Sodium methyl siliconate and Polymethylhydrosiloxane, provided the greatest and most durable hydrophobicity in saline soils. Their different formation mechanisms at particle- and nano-scale were also discussed. A further assessment on the soil mechanical properties revealed that both compaction behavior and strength were negligibly influenced by these two agents.
危险品化学品经营许可证（带存储）