A FACILE SUPERHYDROPHOBIC FABRICATION OF MELAMINE SPONGE FOR OIL ABSORPTION AND OIL/WATER SEPARATION

Abstract

Superhydrophobic oil sorbent materials with highly oil absorption capacity, good durability and superior recyclability have attracted much interest in both academia and industry due to their potential for practical applications, such as self-cleaning, anti-wetting, anti-icing, anti-corrosion, etc. Superhydrophobic surfaces could help to minimizing the energy and water required for cleaning, reducing the utilization of pollution and waste caused by cleaning process and even can be applied for oil/water separation - one of the biggest issues in environmental field at this moment. One of the major challenges is the stability of materials when working on corrosive solutions. This dissertation investigates the fabrication, characterization of superhydrophobic open-cell sponge and its environmental applications. There are numerous natural superhydrophobic materials, such as lotus leaf, rose petal, butterfly wings and water spider legs, in both animal and plant species. Inspired by nature, a novel superhydrophobic melamine sponge (MS) with copper oxide (CuO) coating was developed in a fast reaction via a facile and green method. The CuO layer used to roughen the surface of the substrate (MS) was prepared in a microwave to seed copper nucleuses in alkaline medium. Subsequently, the CuO-coated MS sponge was modified with stearic acid (SA) to increase the surface superhydrophobicity. The resulting modified sponge materials showed superior superhydrophobic properties: a static water contact angle (WCA) of 165.1 degree and dynamic WCAs (both sliding and shedding) much lower than 10 degree. In addition, the developed superhydrophobic non-fluorinated materials quickly absorbed various oils in water with high efficiency and selective separation capacity of oil droplets under environmental conditions of harsh resistance such as acidic, salty and alkaline. Moreover, the as-prepared sponges showed great stability and prominent recyclability with excellent sorption capacity retention even after 40 sorption-squeezing cycles under mechanical load tests without losing their superhydrophobicity. The high superhydrophobicity, facile,environmentally friendly fabrication process and low preparation cost of this novel oil sorbent sponge system supports its promising potential as a candidate material for oil spill clean-up, oily wastewater treatment and water remediation.