Study on the application of waste bricks in emulsified oil-water separation

Non-biodegradable waste brick (WB), as a major type of construction waste, is posing disastrous threat to our ecological environment and society. The effective treatment of WB is being demanded urgently, but it is very challenging to cost-effectively recycle WB. Herein, we presented a green resource utilization of WB turned into waste brick grain (WBG) layer by simple physical refining process. Specially, as-obtained WBGs with 100-400 mu m possess super-amphiphilicity and under-liquid special-wettability of approximate underwater superoleophobicity and underoil high-hydrophobicity. Notably, the accumulated WBG layer can be used for separating water-in-oil emulsions (WOE) and oil-in-water emulsions (OWE) only driven by gravity, even though interspaces between WBGs are larger than size of emulsified droplets, exhibiting high separation efficiency and higher filtrate flux than traditional membranes based on "sizesieving" mechanism. Besides, the WBG layer exhibits excellent chemical durability and cycling performance. Therefore, the low-cost WBG layer is anticipated to be an ideal candidate for high-efficient separation of emulsions in large-scale and harsh practical application. This work not only offers a new perspective for resource utilization of WB from construction waste, but also presents a promising material for emulsions separation, showing great potential and value in environmental protection and industrial applications. (C) 2019 Elsevier Ltd. All rights reserved.