Superhydrophobic/superoleophilic starch-based cryogels coated by silylated porous starch/Fe3O4 hybrid micro/nanoparticles for removing discrete oil patches from water

Nanosheet BiOBr Modified Rock Wool Composites for High Efficient Oil/Water Separation and Simultaneous Dye Degradation by Activating Peroxymonosulfate

The development of superlyophobic materials in liquid systems, enabling synchronous oil/water separation and dye removal from water, is highly desirable. In this study, we employed a novel superwetting array-like BiOBr nanosheets anchored on waste rock wool (RW) fibers through a simple neutralization alcoholysis method. The resulting BiOBr/RW fibers exhibited superoleophilic and superhydrophilic properties in air but demonstrated underwater superoleophobic and underoil superhydrophobic characteristics. Utilizing its dual superlyophobicity, the fiber layer demonstrated high separation efficiencies and flux velocity for oil/water mixtures by prewetting under a gravity-driven mechanism. Additionally, the novel BiOBr/RW fibers also exhibited excellent dual superlyophobicity and effective separation for immiscible oil/oil systems. Furthermore, the BiOBr/RW fibers could serve as a filter to continuously separate oil/water mixtures with high flux velocity and removal rates (>93.9%) for water-soluble dye rhodamine B (RhB) simultaneously by directly activating peroxymonosulfate (PMS) in cyclic experiments. More importantly, the mechanism of simultaneous oil/water separation and RhB degradation was proposed based on the reactive oxygen species (ROS) quenching experiments and electron paramagnetic resonance (EPR) analysis. Considering the simple modified process and the waste RW as raw material, this work may open up innovative, economical, and environmentally friendly avenues for the effective treatment of wastewater contaminated with oil and water-soluble pollutants.

A comprehensive review on anticorrosive/antifouling superhydrophobic coatings: Fabrication, assessment, applications, challenges and future perspectives

Superhydrophobicity (SHP) is an incredible phenomenon of extreme water repellency of surfaces ubiquitous in nature (E.g. lotus leaves, butterfly wings, taro leaves, mosquito eyes, water-strider legs, etc). Historically, surface exhibiting water contact angle (WCA) > 150° and contact angle hysteresis <10° is considered as SHP. The SHP surfaces garnered considerable attention in recent years due to their applications in anti-corrosion, anti-fouling, self-cleaning, oil-water separation, viscous drag reduction, anti-icing, etc. As corrosion and marine biofouling are global problems, there has been focused efforts in combating these issues using innovative environmentally friendly coatings designs taking cues from natural SHP surfaces. Over the last two decades, though significant progress has been made on the fabrication of various SHP surfaces, the practical adaptation of these surfaces for various applications is hampered, mainly because of the high cost, non-scalability, lack of simplicity, non-adaptability for a wide range of substrates, poor mechanical robustness and chemical inertness. Despite the extensive research, the exact mechanism of corrosion/anti-fouling of such coatings also remains elusive. The current focus of research in recent years has been on the development of facile, eco-friendly, cost-effective, mechanically robust chemically inert, and scalable methods to prepare durable SHP coating on a variety of surfaces. Although there are some general reviews on SHP surfaces, there is no comprehensive review focusing on SHP on metallic and alloy surfaces with corrosion-resistant and antifouling properties. This review is aimed at filling this gap. This review provides a pedagogical description with the necessary background, key concepts, genesis, classical models of superhydrophobicity, rational design of SHP, coatings characterization, testing approaches, mechanisms, and novel fabrication approaches currently being explored for anticorrosion and antifouling, both from a fundamental and practical perspective. The review also provides a summary of important experimental studies with key findings, and detailed descriptions of the evaluation of surface morphologies, chemical properties, mechanical, chemical, corrosion, and antifouling properties. The recent developments in the fabrication of SHP -Cr-Mo steel, Ti, and Al are presented, along with the latest understanding of the mechanism of anticorrosion and antifouling properties of the coating also discussed. In addition, different promising applications of SHP surfaces in diverse disciplines are discussed. The last part of the review highlights the challenges and future directions. The review is an ideal material for researchers practicing in the field of coatings and also serves as an excellent reference for freshers who intend to begin research on this topic.

Insights into starch-based gels: Selection, fabrication, and application

Starch a natural polymer, has made significant advancements in recent decades, offering superior performance and versatility compared to synthetic materials. This review discusses up-to-date diverse applications of starch gels, their fabrication techniques, and their advantages over synthetic materials. Starch gels renewability, biocompatibility, biodegradability, scalability, and affordability make them attractive. Also, advanced theoretical foundations and emerging industrial technologies could further expand their scope and functions inspiring new applications.

Starch-Based Polymer Materials as Advanced Adsorbents for Sustainable Water Treatment: Current Status, Challenges, and Future Perspectives

Over the past three decades, chemical and biological water contamination has become a major concern, particularly in the industrialized world. Heavy metals, aromatic compounds, and dyes are among the harmful substances that contribute to water pollution, which jeopardies the human health. For this reason, it is of the utmost importance to locate methods for the cleanup of wastewater that are not genuinely effective. Owing to its non-toxicity, biodegradability, and biocompatibility, starch is a naturally occurring polysaccharide that scientists are looking into as a possible environmentally friendly material for sustainable water remediation. Starch could exhibit significant adsorption capabilities towards pollutants with the substitution of amide, amino, carboxyl, and other functional groups for hydroxyl groups. Starch derivatives may effectively remove contaminants such as oil, organic solvents, pesticides, heavy metals, dyes, and pharmaceutical pollutants by employing adsorption techniques at a rate greater than 90%. The maximal adsorption capacities of starch-based adsorbents for oil and organic solvents, pesticides, heavy metal ions, dyes, and pharmaceuticals are 13,000, 66, 2000, 25,000, and 782 mg/g, respectively. Although starch-based adsorbents have demonstrated a promising future for environmental wastewater treatment, additional research is required to optimize the technique before the starch-based adsorbent can be used in large-scale in situ wastewater treatment.

Combined effects of chemical dispersant and suspended minerals on the dispersion process of spilled oil

The dispersion process of spilled oil is an important concern for the effective disposal of oil spills. The dispersed oil concentration and oil droplets size distribution were studied through a wave tank test under the application of chemical dispersant and suspended minerals. The results indicated that dispersant and minerals increased the dispersed oil concentration and the effect of dispersant was more significant, and they had a synergistic effect on oil dispersion. When dispersant and minerals were applied together, the volume mean diameter of oil droplets decreased in the first 30 min, then increased and reached a maximum value at 90-120 min, and decreased again. Moreover, suspended minerals could inhibit the coalescence of oil droplets. This study can afford data support for oil spill emergency response that occurs in inshore or estuaries.

Recent advances in starch-based magnetic adsorbents for the removal of contaminants from wastewater: A review

Considerable concern exists regarding water contamination by various pollutants, such as conventional pollutants (e.g., heavy metals and organics) and emerging micropollutants (e.g., consumer care products and interfering endocrine-related compounds). Currently, academics are continuously exploring sustainability-related materials and technologies to remove contaminants from wastewater. Magnetic starch-based adsorbents (MSAs) can combine the advantages of starch and magnetic nanoparticles, which exhibit unique critical features such as availability, cost-effectiveness, size, shape, crystallinity, magnetic properties, stability, adsorption properties, and excellent surface properties. However, limited reviews on MSAs' preparations, characterizations, applications, and adsorption mechanisms could be available nowadays. Hence, this review not only focuses on their activation and preparation methods, including physical (e.g., mechanical activation treatment, microwave radiation treatment, sonication, and extrusion), chemical (e.g., grafting, cross-linking, oxidation and esterification), and enzymatic modifications to enhance their adsorption properties, but also offers an all-round state-of-the-art analysis of the full range of its characterization methods, the adsorption of various contaminants, and the underlying adsorption mechanisms. Eventually, this review focuses on the recycling and reclamation performance and highlights the main gaps in the areas where further studies are warranted. We hope that this review will spark an interdisciplinary discussion and bring about a revolution in the applications of MSAs.

Design of Superhydrophobic CoFe2O4 Solar Seawater Desalination Device and Its Application in Organic Solvent Removal

Environmental pollution and clean water production are challenges to the development of human society. In this paper, devices consisting of a superhydrophobic Ni-CoFe₂O₄ foam layer (floating layer), a hydrophilic channel and a superhydrophilic Ni-CoFe₂O₄ foam layer (photothermal conversion layer) were designed. The light energy was converted into heat on the photothermal layer, for which the hydrophilic channel provided a small amount of water. The superhydrophobic layer ensured the floating and selective adsorption of organic solvents on the water surface, whose contact angle reached 157°, and the steam production rate reached 1.68 kg·m⁻²·h⁻¹. Finally, the LSV curve demonstrated that the Ni-CoFe₂O₄ foam prepared had a minimum starting potential, achieving the multifunctionality of the Ni foam.