Degradation of petroleum hydrocarbon pollutants by a superhydrophobic/superoleophilic microbial immobilized core-shell bioreactor

Abstract

Efficient elimination of petroleum hydrocarbon pollution from the environments has received extensive attention due to its severe environmental hazards. Herein, we designed and fabricated a composite bioreactor capable of rapidly and selectively adsorbing petroleum hydrocarbons, specifically diesel, followed by microbial degradation to treat oily wastewater simply and efficiently. Briefly, the bioreactor was prepared using a three-dimensional superhydrophobic/superoleophilic stainless steel mesh as the shell and mixed microbial immobilized kapok fibers as core. By a simple surface modification, the surface water contact angle of the composite bioreactor reaches up to 155°. The high-speed camera's super lipophilic description enables most of the diesel oil to be absorbed within 21 ms. The porosity of the reactor's super hydrophilic kapok fibers aerogel can reach 89%. After immobilized mixed microorganisms, the number of microorganisms increased within 48 h in a favorable environment. The internal space of the reactor shows positive biocompatibility. Afterward, the experimental results of adsorption and degradation for diesel oil show that the degradation rate can reach more than 90% after 204 h, which is about 40% higher than that of the free mixed microorganisms. Compared with the simple method of embedding microorganisms in aerogel, a new core-shell structure microbial reactor is constructed in this paper, which can effectively avoid the risk of microbial leakage and achieve the goal of biodegradation while absorbing oily wastewater. It has constructed a more stable and effective protection space for the continuous degradation of oiling wastewater, while effectively protecting microorganisms from harsh environment, thus showing great potential in various applications such as eliminating organic pollution, oil removal, and wastewater purification.