Abstract Pump and treat of hydrocarbons from the subsurface is largely ineffective because capillary forces impede hydrocarbon mobility. This study uses zein (corn protein) dissolved in water at pH = 13 at low concentrations (4 and 8 g of zein/L) as a natural surfactant to emulsify hydrocarbons, facilitating their recovery from the subsurface (biosurfactant flushing). The effectiveness of zein in emulsifying a model hydrocarbon (toluene) was verified with bottle tests, optical microscopy and confocal microscopy. Interfacial tension measurements conducted with an optical tensiometer and the pendant drop method demonstrated that zein adsorbed onto hydrocarbon-water interfaces. Langmuir-Blodgett interfacial zein films deposited onto glass slides were smooth, as demonstrated using a scanning electron microscope (SEM). Langmuir trough experiments indicate that interfacial zein films either rapidly re-adsorbed or did not desorb from oil-water interfaces upon compression, followed by rapid expansion and recompression. Uncontrolled hydrocarbon migration through the aquifer is a risk associated with surfactant flushing. Therefore, this study also uses zein at high concentrations (33 g of zein/L) to form barriers around the areas where hydrocarbons are emulsified, preventing their migration. Barriers were formed by gelling zein dissolved at pH = 13 with either glacial acetic acid or salts (CaCl2, KCl, and NaCl). Zein gelation was confirmed with compression tests, tensile tests, and shear rheology. Zein gels formed with CaCl2 and glacial acetic acid had the highest shear viscoelastic moduli and tensile strength. The effectiveness of zein gels in impeding contaminant migration was demonstrated in flow experiments conducted using sand columns. This study is a proof of concept that zein can be simultaneously injected in the polluted zones to emulsify hydrocarbons to enhance their recovery, and around the polluted areas to ensure that they are safely contained.

中文翻译：

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用于碳氢化合物修复的玉米醇溶蛋白：乳化剂、捕集剂，还是两者兼而有之？

摘要 从地下泵送和处理碳氢化合物在很大程度上是无效的，因为毛细力阻碍了碳氢化合物的流动。本研究使用低浓度（4 和 8 克玉米蛋白/L）溶解在 pH = 13 的水中的玉米蛋白（玉米蛋白）作为天然表面活性剂来乳化碳氢化合物，促进它们从地下回收（生物表面活性剂冲洗）。玉米蛋白在乳化模型碳氢化合物（甲苯）中的有效性通过瓶子测试、光学显微镜和共聚焦显微镜进行了验证。用光学张力计和悬滴法进行的界面张力测量表明玉米醇溶蛋白吸附在碳氢化合物-水界面上。用扫描电子显微镜 (SEM) 证明，沉积在载玻片上的 Langmuir-Blodgett 界面玉米醇溶蛋白薄膜是光滑的。Langmuir 槽实验表明，界面玉米醇溶蛋白膜在压缩后快速重新吸附或不从油水界面解吸，然后快速膨胀和重新压缩。通过含水层不受控制的烃迁移是与表面活性剂冲洗相关的风险。因此，本研究还使用高浓度玉米醇溶蛋白（33 g 玉米醇溶蛋白/L）在烃类乳化区域周围形成屏障，防止其迁移。屏障是通过将在 pH = 13 下溶解的玉米蛋白与冰醋酸或盐（CaCl2、KCl 和 NaCl）胶凝而形成的。玉米蛋白凝胶化通过压缩试验、拉伸试验和剪切流变学得到证实。用 CaCl2 和冰醋酸形成的玉米醇溶蛋白凝胶具有最高的剪切粘弹性模量和拉伸强度。使用沙柱进行的流动实验证明了玉米蛋白凝胶在阻止污染物迁移方面的有效性。这项研究证明了玉米蛋白可以同时注入污染区域以乳化碳氢化合物以提高其回收率，并在污染区域周围确保它们被安全控制。