Abstract
Environmental remediation using green approaches for addressing various pollution-related issues, especially water pollution, is in high demand. Here, we designed an environmentally friendly, low-cost, and stable sodium alginate–halloysite clay composite aerogel (SAHA) for oil/water separation via a two-step synthesis procedure, including ionic crosslinking and freeze-drying. The as-prepared SAHA aerogels were characterized in detail by scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), and Fourier transformation infrared (FT-IR) spectroscopy. Characterization of the SAHA aerogels revealed a three-dimensional porous microstructure with uniformly dispersed halloysite nanotubes (HA) within the alginate matrix. The elemental composition of the hydrogels investigated using energy dispersive X-ray spectrometry (EDX) revealed the presence of minerals, such as magnesium, sodium, aluminum, and silicon in the SAHA aerogels. The presence of a hydrophilic alginate matrix combined with these unique morphological characteristics resulted in SAHA aerogels with underwater oleophobicity and excellent oil/water separation efficiency (up to 99.7%). The ease of fabrication, excellent oil/water separation, and multiple performances make the SAHA aerogel an interesting candidate for practical applications in water recycling.
Highlights
Aquatic pollution caused by frequent oil spills or contaminants from industries, such as petrochemical, food, textile, and steel industries, has severely affected marine ecology as well as human beings
In this study, a two-step freeze-drying process was employed for the preparation of Sodium alginate (SA) and sodium alginate–halloysite clay composite aerogel (SAHA) aerogels
The same steps were followed for the preparation of the SAHA aerogel except for the addition of halloysite nanoclay tubes to the alginate solution
Summary
Aquatic pollution caused by frequent oil spills or contaminants from industries, such as petrochemical, food, textile, and steel industries, has severely affected marine ecology as well as human beings. Three-dimensional, highly porous structures, such as aerogel foams with extremely low density, are widely used as effective absorbents for oil/water mixtures [10]. To make these foams superhydrophobic for oil absorption, various treatments, such as silane coupling or sulfonation, are carried out, which further increases the cost of production [11]. To the best of our knowledge, there is no report regarding the use of alginate–halloysite composite aerogels for oil/water separation applications. The effect of halloysite clay nanotubes on the oil/water separation efficiency of the aerogel is evaluated
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