Bioinspired Glycolipids - Applications for Mitigating Airborne Dust Pollution

Airborne dust particulates are a major constituent of total atmospheric pollution affecting global environmental and human health that must be urgently mitigated. Particulate matter (PM) with diameter &lt; 10 μm is deeply inhaled into the lungs, causing significant human health risks particularly for cardiovascular and respiratory health. PM is also environmentally harmful, affecting global biogeochemical cycles, polluting water bodies and air masses, and impacting global climate. Control of fugitive dust emissions is a major operational challenge to various industries including construction, agriculture, transportation, energy, and mining. Previous dust suppressant materials have included amphiphilic synthetic polymers as water additives, which interact with dust particles after water evaporation due to their amphiphilic properties and encourage particle agglomeration, thus suppressing dust generation. However, these synthetic polymers and other conventional dust suppressant materials have short-term effectiveness, are corrosive to machinery, and increase toxicity concerns to both humans and the environment.<br/><br/>Herein, bioinspired glycolipids are being investigated as alternative dust suppressants to conventional amphiphilic polymers. Glycolipids are naturally-occurring molecules consisting of sugar and lipid moieties, thus making them amphiphilic molecules with both hydrophobic and hydrophilic properties. While glycolipids can be extracted from bacterial membranes, there are issues with batch size and ill-defined and inconsistent mixtures, causing further problems for quality control. By synthetically manufacturing glycolipids, quality control issues are mitigated, and the processing provides the ability to modify their molecular structures and physiochemical properties.<br/><br/>We have investigated the relationship between dust suppression performance and molecular structures of glycolipids by varying (1) sugar head type, (2) sugar head number, (3) lipid tail length and (4) lipid tail number. Static and dynamic characterization methods have revealed that specific sugar heads, lipid tail lengths, and number of sugar heads/lipid tails influence the self-assembled structures of glycolipids and their interactions with dust particles, resulting in enhancing or diminishing of dust suppression capabilities. Specifically, glycolipids with single rhamnose and xylose sugar head demonstrated up to 90% better dust suppression performance compared to the water control, and both types also produced further enhanced dust suppression properties as their lipid tail lengths increased. Furthermore, those glycolipids with double lipid tails demonstrated excellent dust suppression performance &gt; 95% better than the water control, indicating that the addition of a second lipid tail may enhance the wetting interaction of the glycolipids with small particles. This was further investigated through ATR-FTIR, DLS and SEM, and specific details will be discussed. Additionally, thermal characterization via DSC shows that several glycolipid types undergo a phase change to liquid at approximately 50°C and maintain the liquid phase at normal temperature. Our previous work with liquid amphiphilic polymers has shown that they are highly effective dust suppressants because their liquid phase facilitates more efficient physical interactions between the polymer and small particles, and this glycolipid phase change mechanism appears to follow a similar mechanism to those previously observed.<br/><br/>This work presents that bioinspired glycolipids are promising dust suppressant materials, and the ability to tune their molecular structures allows us to further enhance their dust suppression performance. Our findings are expected to facilitate the development of highly-efficient glycolipid structures to effectively reduce airborne dust levels contributing to enhanced human health and environmental safety.