Fabrication of Highly Anti-droplet Sand Mulches with Enhanced Water Holding Capacity and Oil-water Separation

Abstract

Evaporative loss of water from the upper layer of soil in the arid areas became the burning environmental issue. However, artificial plastics that mimic sand mulches may minimize the evaporative loss of water. These plastic mulches possess utility limitation due to their cost and non-biodegradability. In response, a highly anti-droplet sand mulches have been produced for reducing the evaporation loss of water. A simple modification was conducted for fabricating hydrophobic sand mulches with a high contact angle more than 150º and a lower rolling off angle less than 10º. In this experiment, the sea-sand was also modified by applying an anti-droplet coating using a silica sol, which has been modified to attain hydrophobicity. The produced anti-droplet sand mulches were characterised by Fourier transformed infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS). This hydrophobic sand mulches with core-shell structure have the capability of withholding water for longer period of time which could benefit the agriculture in the arid regions. The modified sands can also be applied as oil sorbent to absorb oil (chloroform) from water selectively because of water repellence characteristics. In this study, the application of this hydrophobic coating is a simple approach to offer anti-droplet and self- cleaning features to sand mulches for various applications.