Comprehensive experimental design of enzyme etching to prepare superhydrophobic materials and evaluate oil-water separation performance

Comprehensive experiments play a crucial role in the teaching work in universities. In accordance with the characteristics of the school, disciplines, and talent cultivation requirements, constructing comprehensive experiments can help students understand the theoretical knowledge in textbooks and cultivate students’ innovative thinking ability to solve problems independently. In comprehensive experiments, the scope of theoretical knowledge involved is extensive. For teachers, transforming their research achievements into comprehensive experimental teaching can not only organically connect teaching and research but also attract more students toward participating in innovative experiments. Further, this provides a broader enlightenment of scientific thinking. The rising global population, coupled with the increasing need for industrial development, has generated a significant amount of oily wastewater, which requires urgent treatment. This wastewater primarily stems from various domestic and industrial activities. Currently, traditional oil-water separation processes suffer from several shortcomings, including high operational costs, low separation efficiency, poor oil recovery, and adverse environmental impact caused by fluorine that is contained in some separation materials. In accordance with the concept of green and environmental protection, this paper introduces the preparation of superhydrophobic materials using enzyme etching into comprehensive experimental teaching by capitalizing on the high efficiency and mild reaction conditions of enzymes. This experiment successfully produced superhydrophobic cotton fabric and explored its application prospects in the field of oil-water separation.

In this comprehensive experiment, a micro-nano rough structure was introduced on the surface of the fabric through cellulase etching. By utilizing non-fluorinated reactions, superhydrophobic cotton fabric was successfully prepared through physical dipping and coating methods using a long-chain alkyl silane coupling agent (hexadecyltrimethoxysilane, HDTMS) as a low surface energy modifier. The micro-surface morphology, wettability, and elemental analysis of the pristine, enzyme-etched, and superhydrophobic cotton fabrics were characterized by scanning electron microscopy (SEM), contact angle measurement, Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). Furthermore, the experiment evaluated the physical properties and wettability of both the pristine cotton fabric and the superhydrophobic cotton fabric. Finally, the separation efficiency of oil-water mixtures containing n-hexadecane, kerosene, peanut oil, silicone oil, and carbon tetrachloride was evaluated using a self-fabricated oil-water separation device. The study also explored the application prospects of superhydrophobic cotton fabric in the field of oil-water separation.

The experimental results showed that by utilizing cellulase to etch the surface of the fabric to produce rough structures and then modifying its surface with HDTMS, a superhydrophobic cotton fabric with a contact angle of 154.4° was obtained. An analysis of the surface functional groups and element distribution of the fabric using FTIR and XPS reveals that the long chain of HDTMS is successfully grafted onto the surface of the cotton fabric. Additionally, the resulting superhydrophobic cotton fabric exhibits excellent self-cleaning properties and highly efficient oil-water separation performance, yielding separation efficiencies of over 95% for oils with low viscosity and better fluidity.

This innovative experimental design is safe and cost-effective. The preparation is carried out under normal temperature and pressure, making it practically feasible for comprehensive experimental teaching in undergraduate chemical sciences. The experimental design focuses on enhancing students’ research experience, which is conducive to sparking their enthusiasm and interest in scientific research. Moreover, the content of the experiment encompasses the integrated application of various chemical theoretical knowledge, contributing to the development of students’ research literacy and independent innovation thinking abilities.