A facile energy-saving and environmental oil-spill remedial method: Separation patterns and kinetics research

[Display omitted] •Superhydrophobic sponge was obtained with facile two-step method: self-assembly and interface chemistry.•Continuous and effective oil/water separation was achieved with peristaltic pump.•Theory for optimization of oil/water separation was proposed.•Separation patterns and kinetics for different oil/organics could be predicted with established math model. Three-dimensional porous sponge has been demonstrated as an outstanding candidate in oil/water separation due to its hydrophobicity and oleophilicity that originates from the synergistic effect of rough structure and low surface energy, but the separation process has not been illuminated clearly. This paper presents the study of the synthesis of oil/water separation sponge, mechanism of separation process and establishment of kinetic model, via the combination among dopamine chemistry, covalent modification, theoretical analysis, experimental results and mathematical model. Results show that both the dopamine deposition time and the octadecyltrimethoxysilane hydrolysis system significantly affect the hydrophobicity of the modified-melamine sponge and that the oil/water separation process is composed of six scenarios with different physical state. Furthermore, with the experimental results, established iso-potential separation model and the height-quantized model, we conclude that the time-dependent separation patterns and kinetics are subjected to the modulation of the viscosity of the separated substance and the immersion depth of the sponge.