Eco-friendly and multifunctional superhydrophilic and underwater superoleophobic materials with adsorption, photodegradation and oil-water separation properties

The frequent water pollution problems have caused serious harm to the ecological environment and human health, among which, a large number of waste water contains heavy metal ions, organic dyes, oil-water emulsion and other pollutants. Therefore, it is particularly important to prepare multifunctional materials that can separate these pollutants and purify wastewater. In this paper, ovalbumin (OVA), phytic acid (PA) and egg shell powder (ESP) and TiO2 particles were used to construct a composite system, which was loaded on fabric, cotton and PVDF membrane by impregnation method. The preparation of OVA-ESP-TiO2-PA modified materials which can efficiently separate various oil-water mixtures and oil-water emulsions were successfully achieved. The modified material could achieve high flux (up to13458 L m−2h−1) and separation efficiency (＞99 %) for various mixtures of oil and water by gravity-driven. Typically, it shows good stability and durability under strong acid and alkali (pH=1–12) and different temperatures (T = 10–60 ℃), and can be reused. What's more, the modified materials can effectively adsorb organic dyes (＞92 %) and heavy metal ions (up to 85 %) and can degrade organic dyes by ultraviolet light. It provides a new idea for the separation of oil-water mixture and the purification of waste liquid containing organic dyes and heavy metal ions, which has a good application prospect in the treatment of industrial wastewater and domestic wastewater.