Zhang Chengzhao, Dai Chong, Zhang Huaqin, Peng Shitao, Wei Xin, Hu Yandi
Department of Civil & Environmental Engineering, University of Houston, Houston, TX 77004, United States.
Laboratory of Environmental Protection in Water Transport Engineering, Tianjin Research Institute of Water Transport Engineering, Tianjing 300456, China.
Mar Pollut Bull. 2017 Sep 15;122(1-2):129-138. doi: 10.1016/j.marpolbul.2017.06.036. Epub 2017 Jun 27.
Silica aerogel, with mesoporous structure and high hydrophobicity, is a promising adsorbent for oil spill clean-up. To make it economic and environmental-friendly, hydrocarbon desorption and silica aerogel regeneration were investigated. After hydrocarbon desorption at 80°C, silica aerogel maintained its hydrophobicity. After toluene, petrol, and diesel desorption, shrinkage of mesopores (from 19.9 to 16.8, 13.5, and 13.4nm) of silica aerogels occurred, causing decreased adsorption capacities (from 12.4, 11.2, and 13.6 to 12.0, 6.5, and 2.3g/g). Low surface tension of petrol caused high stress on mesopores during its desorption, resulting in significant pore shrinkage. For diesel, its incomplete desorption and oxidation further hindered the regeneration. Therefore, diesel desorption was also conducted at 200°C. Severe diesel oxidation occurred under aerobic condition and destroyed the mesopores. Under anaerobic condition, no diesel oxidation occurred and the decreases in pore size (to 13.2nm) and adsorption efficiency (to 10.0g/g) of regenerated silica aerogels were much less, compared with under aerobic condition. This study provided new insights on silica aerogel regeneration for oil spill clean-up.
具有介孔结构和高疏水性的二氧化硅气凝胶是一种很有前途的溢油清理吸附剂。为了使其经济且环保，对碳氢化合物解吸和二氧化硅气凝胶再生进行了研究。在80°C进行碳氢化合物解吸后，二氧化硅气凝胶保持其疏水性。在甲苯、汽油和柴油解吸后，二氧化硅气凝胶的介孔出现收缩（从19.9降至16.8、13.5和13.4nm），导致吸附容量降低（从12.4、11.2和13.6降至12.0、6.5和2.3g/g）。汽油的低表面张力在解吸过程中对介孔造成高应力，导致显著的孔收缩。对于柴油，其不完全解吸和氧化进一步阻碍了再生。因此，柴油解吸也在200°C下进行。在有氧条件下发生严重的柴油氧化并破坏了介孔。在厌氧条件下，未发生柴油氧化，与有氧条件相比，再生二氧化硅气凝胶的孔径减小（至13.2nm）和吸附效率降低（至10.0g/g）的程度要小得多。这项研究为溢油清理中二氧化硅气凝胶的再生提供了新的见解。
