A solvent-template ethyl cellulose-polydimethylsiloxane crosslinking sponge for rapid and efficient oil adsorption

Degradable polyvinyl alcohol/chitosan@carnauba wax superhydrophobic composite membrane for water-in-oil emulsion separation and heavy metal adsorption

At present, many oil-water separation membranes are being developed to purify oily wastewater. However, oily wastewater often contains heavy metal, which are often difficult to dispose during separation. Furthermore, most of the oil-water separation membranes cannot be degraded after scrap, producing pollution to environment. Herein, the polyvinyl alcohol/chitosan@carnauba wax (PCGCW) membrane with heavy metal adsorption and biodegradation performance was acquired by electrospinning and spraying process. The acquired PCGCW membrane had excellent mechanical properties after crosslinking glutaraldehyde (GA). Furthermore, the composite membrane had excellent superhydrophobic property (WCA = 154°) with a rolling angle of 2°, due to the introduction of carnauba wax. Exhilaratingly, for emulsions with surfactant, it had a high separation flux with 19,217 L·m-2·h-1·bar-1 and splendid an oil purity over 99.9 %. Besides, the efficiency of oil purity and separation flux remained stable even after 10 separations. In addition, the PCGCW membrane had the ability to adsorb heavy metals with adsorption capacity of 51-106 mg/g for Cu2+, Fe3+, Co2+ ions. Foremost, the superhydrophobic PCGCW membrane was biodegradable, with degrading 29.76 % within 40 days. The prepared composite membrane had the advantages of low cost, high separation flux, great repeatability, adsorbable heavy metals and degradability, which had a vast application prospect.

Inside-out templating: A strategy to decorate helical carbon nanotubes and 2D MoS2 on ethyl cellulose sponge for enhanced oil adsorption and oil/water separation

Ethyl cellulose (EC)-based composite sponges were developed for oil spillage treatment. The EC sponge surface was decorated with helical carbon nanotubes (HCNTs) and molybdenum disulfide (MoS2) (1 phr) using the inside-out sugar templating method. The inside surface of a sugar cube was coated with HCNTs and MoS2. After filling the sugar cube pores with EC and the subsequent sugar leaching, the decorating materials presented on the sponge surface. The EC/HCNT/MoS2 sponge had a high level of oil removal based on its adsorption capacity (41.68 g/g), cycled adsorption (∼75-79 %), separation flux efficiency (∼85-95 %), and efficiency in oil/water emulsion separation (92-94 %). The sponge maintained adsorption capacity in acidic, basic, and salty conditions, adsorbed oil under water, and functioned as an oil/water separator in a continuous pump-assisted system. The compressive stress and Young's modulus of the EC sponge increased following its decoration using HCNTs and MoS2. The composite sponge was robust based on cycled compression and was thermally stable up to ∼120 οC. Based on the eco-friendliness of EC, the low loading of HCNTs and MoS2, and sponge versatility, the developed EC/HCNT/MoS2 sponge should be good candidate for use in sustainable oil adsorption and separation applications.

Magnetic Hyperporous Elastic Material with Excellent Fatigue Resistance and Oil Retention for Oil-Water Separation

Oily wastewater has caused serious threats to the environment; thus, high-performance absorbing materials for effective oil-water separation technology have attracted increasing attention. Herein, we develop a magnetic, hydrophobic, and lipophilic hyperporous elastic material (HEM) templated by high internal phase emulsions (HIPE), in which free-radical polymerization of butyl acrylate (BA) and divinylbenzene (DVB) is employed in the presence of poly(dimethylsiloxane) (PDMS), lecithin surfactant, and modified Fe3O4 nanoparticles. The adoption of the emulsion template with nanoparticles as both stabilizers and cross-linkers endows the HEM with biomimetic hierarchical open-cell micropores and elastic cross-linked networks, generating an oil absorbent with outstanding mechanical stability. Compressive fatigue resistance of the HEM is demonstrated to endure 2000 mechanical cycles without plastic deformation or strength degradation. By exploiting the synergistic effect of hierarchical structures and low-surface-energy components, the resulting HEM also possesses excellent and robust hydrophobicity (water contact angle of 164°) and good oil absorption capacity, in which Fe3O4 nanoparticles lead to convenient magnetically controlled oil recyclability as well. Notably, the unique biomimetic microporous structure demonstrates superior oil retention capacity (>95% at 1000 rpm and >60% at 10,000 rpm) over the state-of-the-art porous materials for a diverse variety of oils to reduce the risk of secondary oil leakage, along with good recoverability by squeezing owing to the excellent compression resilience. These excellent performances of our HEM provide broad prospects for practical applications in oil-water separation, energy conversion, and smart soft robotics.

Recent advances in hydrophobic nanocellulose aerogels for oil spill applications: A review

In a rapidly growing world, petroleum is used extensively in various industries, and the extraction, processing, and transportation of petroleum generates large amounts of petroleum-containing wastewater. Conventional oil/water separation methodologies are often ineffective and costly. Nanocellulose-based aerogels (NA) have emerged as a possible solution to this problem. However, hydrophobic modification is required for effective use in oil/water separation. This review on materials commonly used in these processes and outlines the requirements for adsorbent materials and methods for creating unique lipophilic surfaces. New trends in hydrophobization methods for NA are also discussed. Additionally, it includes the development of composite nanocellulose aerogels (CNAs) and cellulose based membrane specially developed for oil/water (o/w) separation considering different separation requirements. This analysis also examines how CNAs have evolved by introducing special properties that facilitate oil collection or make the adsorbent recyclable. We also discuss the difficulties in creating effective NAs for these important applications in a changing society, as well as the difficulties in creating oil recovery equipment for oil spill cleanup.