Oil absorption and plant symbiosis capacity of hydrophobic modified concrete: Preparation and performance analysis

Oil pollution jeopardizing the ecological environment made topical the introduction of "ecological" concrete with high oil pollution adsorption performance. By designing the pore structure of concrete with cementitious materials, modifying it with hydrophobic materials, and combining it with absorptive plant growth experiments, the modified concrete had the function of absorbing oil pollution. This study aimed to prepare a modified oil-absorbent concrete (MOAC) by designing cementitious materials, sand rate, water-cement ratio and combining the modification of hydrophobic materials. This paper focused on the compressive strength, oil absorption performance, and plant symbiosis with centipede grass. Using scanning electron microscopy (SEM), mercury intrusion porosimetry (MIP), and Fourier transform infrared (FT-IR) spectroscopy to analyze the oil absorption mechanism, the impact of hydrophobic materials on oil absorption performance were discussed. The symbiosis between MOAC and plants was explored through vegetation experiments. The crude fat content in the adsorbed plant centipede grass was tested by the Soxhlet extraction method. The results show that the optimal compressive strength of oil-absorbing concrete can reach more than 20 MPa, and the volumetric oil absorption capacity can reach 230.7 kg/m3. The hydrophobic material isooctyltrie thoxysilane can be grafted onto the concrete surface and significantly improve oil absorption performance. After 90 days of plant growth, the survival rate of plants in the MOAC was over 82.01% in the environment where the oil pollution was engine oil and soybean oil. Centipede grass can absorb and degrade oil pollution, and its oil absorption capacity reached 3.81%. Through the degradation of centipede grass and the adsorption of oil stains in the concrete, the integrated design and sustainable development of concrete oil stain adsorption can be achieved.