A reusable, biomass-derived, and pH-responsive collagen fiber based oil absorbent material for effective separation of oil-in-water emulsions

Anisotropic MXene@polydopamine- and Dialdehyde Carboxymethyl Cellulose-Modified Collagen Aerogel Supported Form-Stable Phase Change Composites for Light-To-Heat Conversion and Energy Storage

As a renewable alternative heat source, the inherently intermittent feature of solar energy needs to be coordinated by reliable energy conversion and storage systems for utilizing the most abundant solar energy. Phase change materials (PCMs) are supposed to be advanced mediums for storing a great deal of heat generated by solar light. However, PCMs cannot effectively absorb and utilize solar energy due to leakage, low photothermal conversion efficiency, and poor thermal conductivity. Herein, we developed a collagen-based aerogel modified by dialdehyde carboxymethyl cellulose and polydopamine-modified two-dimensional transition-metal carbide/nitride (MXene@PDA) through bidirectional freeze-drying technology for supporting PCMs, which exhibited anisotropy in structure and properties. In particular, the thermal conductivity of the aerogel was 0.0871 W/(m·K) in the axial direction and 0.0504 W/(m·K) in the radial direction, demonstrating its anisotropic thermal insulation performance. Moreover, the final aerogel composite PCMs had been obtained via impregnating the obtained aerogel supporting matrix into polyethylene glycol (PEG) and hydrophobic treatment of polydimethylsiloxane, which exhibited outstanding solar-thermal conversion ability, good thermal storage capacity, advanced leakage-proof property, and antifouling performance. The loading rate of PEG was as high as 92.2%, and the melting enthalpy was 132.6 J/g. Most importantly, the water contact angle was evaluated to be 156.8°, indicating its superior antifouling performance. This material has intensive application prospects in the fields of solar energy collection, conversion, and storage.

Cellulose/Grape-Seed-Extract Composite Films with High Transparency and Ultraviolet Shielding Performance Fabricated from Old Cotton Textiles

Plastics displaying many merits have been indispensable in daily life and they still maintain the strong momentum of development. Nevertheless, petroleum-based plastics possess a stable polymer structure and most of them are incinerated or accumulated in the environment, leading to devastating impacts on our ecology system. Thus, exploiting renewable and biodegradable materials to substitute or replace these traditional petroleum-derived plastics is an urgent and important task. In this work, renewable and biodegradable all-biomass cellulose/grape-seed-extract (GSEs) composite films with high transparency and anti-ultraviolet performance were fabricated successfully from pretreated old cotton textiles (P-OCTs) using a relatively simple, green, yet cost-effective, approach. It is proved that the obtained cellulose/GSEs composite films exhibit good ultraviolet shielding performance without sacrificing their transparency, and their UV-A and UV-B blocking values can reach as high as nearly 100%, indicating the good UV-blocking performance of GSEs. Meanwhile, the cellulose/GSEs film show higher thermal stability and water vapor transmission rate (WVTR) than most common plastics. Moreover, the mechanical property of the cellulose/GSEs film can be adjusted by the addition of a plasticizer. Briefly, the transparent all-biomass cellulose/grape-seed-extracts composite films with high anti-ultraviolet capacity were manufactured successfully and they can be used as potential materials in the packaging field.

Scalable and switchable CO2-responsive membranes with high wettability for separation of various oil/water systems

Smart membranes with responsive wettability show promise for controllably separating oil/water mixtures, including immiscible oil-water mixtures and surfactant-stabilized oil/water emulsions. However, the membranes are challenged by unsatisfactory external stimuli, inadequate wettability responsiveness, difficulty in scalability and poor self-cleaning performance. Here, we develop a capillary force-driven confinement self-assembling strategy to construct a scalable and stable CO2-responsive membrane for the smart separation of various oil/water systems. In this process, the CO2-responsive copolymer can homogeneously adhere to the membrane surface by manipulating the capillary force, generating a membrane with a large area up to 3600 cm2 and excellent switching wettability between high hydrophobicity/underwater superoleophilicity and superhydrophilicity/underwater superoleophobicity under CO2/N2 stimulation. The membrane can be applied to various oil/water systems, including immiscible mixtures, surfactant-stabilized emulsions, multiphase emulsions and pollutant-containing emulsions, demonstrating high separation efficiency (>99.9%), recyclability, and self-cleaning performance. Due to robust separation properties coupled with the excellent scalability, the membrane shows great implications for smart liquid separation.

Recent Advances in Biomass-Based Materials for Oil Spill Cleanup

Oil spill on sea surfaces, which mainly produced by the oil leakage accident happened on tankers, offshore platforms, drilling rigs and wells, has bring irreversible damage to marine environments and ecosystems. Among various spill oil handling methods, using sorbents to absorb and recover spill oils is a perspective method because they are cost-effective and enable a high recovery and without secondary pollution to the ecosystem. Currently, sorbents based on biomass materials have aroused extensively attention thanks to their features of inexpensive, abundant, biodegradable, and sustainable. Herein, we comprehensively review the state-of-the-art development of biomass-based sorbents for spill oil cleanup in the recent five years. After briefly introducing the background, the basic theory and material characteristics for the separation of oil from water and the adsorption of oils is also presented. Various modification methods for biomass materials are summarized in section three. Section four discusses the recent progress of biomass as oil sorbents for oil spill cleanup, in which the emphasis is placed on the oil sorption capacity and the separation efficiency. Finally, the challenge and future development directions is outlined.