Superhydrophobic, flexible and gas-permeable membrane prepared by a simple one-step vapor deposition

Facile Preparation of Superhydrophobic PDMS Polymer Films with Good Mechanical Strength Based on a Wear-Resistant and Reusable Template

In this paper, a new method involving a wear-resistant and reusable template is proposed for the preparation of high-mechanical-strength superhydrophobic polymer film based on wire electrical discharge machining (WEDM). A solid-liquid-contact-angle simulation model was established to obtain surface-texture types and sizes that may achieve superhydrophobicity. The experimental results from template preparation show that there is good agreement between the simulation and experimental results for the contact angle. The maximum contact angle on the template can reach 155.3° given the appropriate triangular surface texture and WEDM rough machining. Besides, the prepared superhydrophobic template exhibits good wear resistance and reusability. PDMS superhydrophobic polymer films were prepared by the template method, and their properties were tested. The experimental results from the preparation of superhydrophobic polymer films show that the maximum contact angle of the polymer films can be up to 154.8° and that these films have good self-cleaning and anti-icing properties, wear resistance, bending resistance, and ductility.

Bio-inspired and metal-derived superwetting surfaces: Function, stability and applications

Due to their exceptional anti-icing, anti-corrosion, and anti-drag qualities, biomimetic metal-derived superwetting surfaces, which are widely employed in the aerospace, automotive, electronic, and biomedical industries, have raised significant concern. However, further applications in other domains have been hampered by the poor mechanical and chemical durability of superwetting metallic surfaces, which can result in metal fatigue and corrosion. The potential for anti-corrosion, anti-contamination, anti-icing, oil/water separation, and oil transportation on surfaces with superwettability has increased in recent years due to the advancement of research in biomimetic superwetting interface theory and practice. Recent developments in functionalized biomimetic metal-derived superwetting surfaces were summarized in this paper. Firstly, a detailed presentation of biomimetic metal-derived superwetting surfaces with unique capabilities was made. The problems with the long-term mechanical and chemical stability of biomimetic metal-derived superwetting surfaces were then examined, along with potential solutions. Finally, in an effort to generate fresh concepts for the study of biomimetic metal-derived superwetting surfaces, the applications of superwetting metallic surfaces in various domains were discussed in depth. The future direction of biomimetic metal-derived superwetting surfaces was also addressed.

A Review on Nanocellulose and Superhydrophobic Features for Advanced Water Treatment

Globally, developing countries require access to safe drinking water to support human health and facilitate long-term sustainable development, in which waste management and control are critical tasks. As the most plentiful, renewable biopolymer on earth, cellulose has significant utility in the delivery of potable water for human consumption. Herein, recent developments in the application of nanoscale cellulose and cellulose derivatives for water treatment are reviewed, with reference to the properties and structure of the material. The potential application of nanocellulose as a primary component for water treatment is linked to its high aspect ratio, high surface area, and the high number of hydroxyl groups available for molecular interaction with heavy metals, dyes, oil-water separation, and other chemical impurities. The ability of superhydrophobic nanocellulose-based textiles as functional fabrics is particularly acknowledged as designed structures for advanced water treatment systems. This review covers the adsorption of heavy metals and chemical impurities like dyes, oil-water separation, as well as nanocellulose and nanostructured derivative membranes, and superhydrophobic coatings, suitable for adsorbing chemical and biological pollutants, including microorganisms.

Membrane-based zero-sludge palm oil mill plant

The palm oil industry is one of the most important agro-industries for tropical countries because of the unique properties and wide range of uses of palm oil for various end products. In a palm oil extraction process, a large quantity of water is required, of which half the quantity will end up as effluent. This palm oil mill effluent (POME) has an extremely high content of organic matter, which can cause severe pollution of waterways and other environmental problems. Disposal of this highly polluting effluent has become a major problem for the palm oil mills. Therefore, several methods have been proposed either to treat the POME so it could comply with environmental regulation while discharged or to recover water and other valuable components from the effluent. Membrane technology has emerged as a feasible alternative to conventional treatment in vegetable oil processing because of its attractive features such as low energy consumption, reduction in the number of processing steps, high separation efficiency, and improvement of the final product quality. In the case of POME treatment, an integrated membrane-based process promises efficient water recycling and total solid recovery from the effluent, thus eliminating the environmental problem. Recently, a novel concept combining oil–oil extraction and continuous filtration using a superhydrophobic membrane has been proposed to achieve a zero-sludge palm oil mill. In this concept, the huge wastewater effluent generated from the conventional process can be eliminated and the palm oil milling process simplified. Furthermore, the superhydrophobic membrane enables the production of high-purity palm oil. In this paper, we review the prospect of a zero-sludge palm oil mill concept and strategies to achieve the proposed concept. In addition, we also highlight the development of the superhydrophobic membrane and phytonutrient recovery.