Preparation of Halloysite-Based Superhydrophobic Aerogels for Oil–Water Separation
Yue Pan, Zhaoqi Zhu, Li Min, Yanjun Chen, Chenchen Cheng, Mingxing Wang, Hanxue Sun, An Li
Abstract
The frequent occurrence of oil spill accidents and the massive discharge of oily wastewater have become serious environmental pollution problems. Herein, we report a facile and easy method for fabricating superhydrophobic halloysite-based aerogels (PDMS@HNCS) through mixing halloysite and chitosan without cross-linking agents. The as-prepared aerogel with an aligned tubular channel structure has low density (41.98–52.83 mg cm –3 ) and robust mechanical properties because of the directional freezing and freeze-drying method. The dip-coating method and heat treatment of the halloysite-based aerogels with PDMS endow them with superhydrophobic properties, which is beneficial for selective adsorption and separation of oil–water mixtures, and the contact angle with water of PDMS@HNCS aerogels can reach 151.4°. The adsorption capacity of the aerogel for various oils or organic solvents is 10.13–22.61 g g –1 . Besides, the aerogel can separate various water-in-oil emulsions with high separation efficiencies of up to 99.90%. Overall, clay-based aerogels have gradually attracted attention in the field of oil–water separation owing to their low density, good absorption properties, and biocompatibility, and this work may develop a new approach to fabricating materials for efficient oil–water separation by using a simple method and low-cost materials.