Achieving ultrahigh uranium/vanadium selectivity of poly(amidoxime) via coupling MXene-enabled strong intermolecular interaction and separated photothermal interface.

Poly(amidoxime) (PAO) has been recognized as the most potential candidate for extracting uranium from seawater, owing to its merits of outstanding uranium affinity, low cost, and large-scale production. Despite remarkable achievements, existing PAO sorbents suffer from unsatisfactory uranium extraction efficiency and selectivity, as imposed by the inherently sluggish uranium adsorption kinetics and inevitable spatial configuration transition of amidoxime, which diminishes uranium affinity. Herein, we discover a facile and integrated design to elaborate a PAO/MXene nanocomposite that delivers ultrahigh and durable uranium/vanadium (U/V) selectivity. The key to our design lies in harnessing MXene-enabled strong intermolecular interactions to PAO to minimize the spatial configuration transition of amidoxime and stabilizing its superior uranium affinity, as well as creating a separated photothermal interface to maximize temperature-strengthened affinity for uranium over vanadium. Such a synergetic effect allows the nanocomposite to acquire over a 4-fold improvement in U/V selectivity compared to that of pure PAO as well as an unprecedented distribution coefficient of uranium compared to most state-of-the-art sorbents. We further demonstrate that our nanocomposite exhibits durable U/V selectivity with negligible attenuation and good antibacterial ability even in long-term operation. The design concept and extraordinary performance in this study bring PAO-based sorbents a step closer to practical uranium extraction from seawater.

Nanocellulose interface enhanced all-cellulose foam with controllable strength via a facile liquid phase exchange route.

The development of sustainable, biodegradable, non-toxic biomass foams with outstanding physical properties to replace traditional petroleum-based foams is urgent. In this work, we proposed a simple, efficient, and scalable approach to fabricate nanocellulose (NC) interface enhanced all-cellulose foam through ethanol liquid phase exchange and subsequent ambient drying. In this process, NCs served as reinforcer and binder were integrated with pulp fiber to improve cellulose interfibrillar bonding and interface adhesion between NCs and pulp microfibrils. The resultant all-cellulose foam displayed stable microcellular structure (porosity of 91.7-94.5 %), low apparent density (0.08-0.12 g/cm3), and high compression modulus (0.49-2.96 MPa) by regulating the content and size of NCs. Further, the strengthening mechanism of the structure and property of all-cellulose foam were investigated in detail. This proposed process enabled ambient drying, and is simple and feasible for low-cost, practicable, and scalable production of biodegradable, green bio-based foam without special apparatuses and other chemicals.

Template-mediated copper doped porous g-C3N4 for efficient photodegradation of antibiotic contaminants.

Graphite carbon nitride (g-C3N4) has great potential to treat antibiotic wastewater, but limited by small specific surface area, rapid recombination of photogenerated carriers and narrow visible light absorption range. In order to solve above problems, we designed a simple template-mediated approach by supramolecular self-assembly (Cu-melamine-cyanuric acid) to prepare copper doped porous graphitic carbon nitride (Cu-pCN) photocatalyst. The pre-organized template self-assembly driven by hydrogen bonds and electrostatic interaction, resulted in highly porous structure. The specific surface area of Cu-pCN increased to 142.8 m2/g from 11.37 m2/g of conventional bulk g-C3N4. In addition, the doping of Cu endowed them with better light absorption, higher separation and transfer rate of photogenerated carriers. Consequently, the obtained Cu-pCN displayed the superior photocatalytic degradation rate for tetracycline (TC) and high recycling stability.

Janus Metal-Organic Frameworks/Wood Aerogel Composites for Boosting Catalytic Performance by Le Châtelier's Principle.

Elaborate design of metal-organic frameworks (MOFs) composites with enhanced properties is of fundamental interest and practical importance in the fields of catalysis. Typical strategies are usually focused on how to increase MOFs contents while lacking architecture design for performance improvements. Herein, we first report MOFs composites with Janus structures to boost catalytic performance by Le Châtelier's principle when using wood aerogel as a versatile platform. Janus structures mean that one part of the composite is still wood aerogel while the other part is decorated with MOFs. The underoil hydrophilicity of the wood aerogels endows the Janus composites with dehydration capacity for promoting the equilibrium movement so as to boost the catalytic performance. The catalytic performance of Janus composites for the Knoevenagel reaction increases more than 40% compared with those symmetric composites. Moreover, both the final conversion and the reaction rate are much better for the Janus composites than other state-of-the-art heterogeneous ZIF-8-based catalysts. Our design is general and paves the way to exploit composites with special architecture.

Sandwich-Structured Photothermal Wood for Durable Moisture Harvesting and Pumping.

Moisture capture coupled with photothermal regeneration provides an alternative and sustainable way to acquire fresh water. Composite moisture absorbents based on hygroscopic salts are environmentally friendly, economically feasible, and of high efficiency but suffer from the unavoidable desiccant leakage during absorption and evaporation-induced salt accumulation on material surfaces during desorption. In this study, we develop a superhydrophobic-hydrophilic-hydrophobic photothermal wood embedded with CaCl2 to promote the durability of the absorbents. The sandwich structure serves as a liquid/vapor gate allowing vapor transport but forbidding liquid permeation, enabling the condensation and evaporation within the wood. Beyond moisture harvesting, the sandwich-structured photothermal wood exhibits potential in indoor dehumidification by pumping the moisture through an absorption-desorption cycle.

Outdoor Personal Thermal Management with Simultaneous Electricity Generation.

Outdoor personal thermal comfort is of substantial significance to ameliorate the health conditions of pedestrian and outdoor laborer. However, the uncontrollable sunlight, substantial radiative loss, and intense temperature fluctuations in the outdoor environment present majestic challenges to outdoor personal thermal management. Here, we report an eco-friendly passive nanostructured textile which harvests energy from the sun and the outer space for optional localized heating and cooling. Compared to conventional heating/cooling textiles like black/white cotton, its heating/cooling mode enables a skin simulator temperature increase/decrease of 8.1 °C/6 °C, respectively, under sunlight exposure. Meanwhile, the temperature gradient created between the textile and human skin allows a continuous electricity generation with thermoelectric modules. Owing to the exceptional outdoor thermoregulation ability, this Janus textile is promising to help maintain a comfortable microclimate for individuals in outdoor environment and provide a platform for pervasive power generation.

Efficient removal of cationic dyes via activated carbon with ultrahigh specific surface derived from vinasse wastes.

In this work, a simple and feasible approach for converting waste vinasse generated from the alcohol industries into high value-added activated carbon (AC) was proposed. The obtained AC possessed abundant micropores with micropore volume of 0.9613 cm3/g and ultrahigh specific surface areas (2015 m2/g), indicating prominent adsorption capacity. The adsorption ability of AC to cationic methylene blue (MB) was investigated systematically. The resultant AC exhibited superior adsorption ability to MB with a maximum amount of 2251 mg/g, derived from its excellent pore textural features and abundant surface O-containing functional groups. Moreover, AC showed excellent removal efficiency for treating industrial polyacrylonitrile wastewater with 99% removal within 60 min. Our results provide great inspirations in solid waste treatment and their high value-added transformation, meanwhile exploit a promising application of AC for practical wastewater purification.

Lysozyme Membranes Promoted by Hydrophobic Substrates for Ultrafast and Precise Organic Solvent Nanofiltration.

Organic solvent nanofiltration (OSN) is regarded as a promising separation technology in chemical and pharmaceutical industries. However, it remains a great challenge in fabricating OSN membranes with high permeability and precise selectivity by simple, transfer-free, and up-scalable processes. Herein, we report lysozyme nanofilm composite membranes (LNCM) prepared by one-step methods with hydrophobic substrates at the air/water interface. The microporous substrates not only promote the heterogeneous nucleation of amyloid-like lysozyme oligomers to construct small pores in the formed nanofilms but also benefit for the simultaneous composition of LNCM via hydrophobic interactions. The constructed nanopores are reduced to around 1.0 nm, and they are demonstrated by grazing incidence small-angle X-ray scattering with a closely packed model. The LNCM can tolerate most organic polar solvents and the permeability surpasses most of state-of-the-art OSN membranes.

Janus Membranes with Charged Carbon Nanotube Coatings for Deemulsification and Separation of Oil-in-Water Emulsions.

Oil/water separation, especially for those surfactant-stabilized oil-in-water (O/W) emulsions, is required to protect our ecological environment from destruction. Janus membranes with a function of deemulsification appear as a kind of efficient materials for the separation of O/W emulsions because of a precise adjustment of the surface nature for the hydrophilic and hydrophobic layers. However, existing strategies of membrane preparation suffer from complicated multisteps, leading to uncontrolled thickness of the hydrophilic deemulsification layer. Herein, we present a facile and tunable method to prepare a series of Janus membranes consisting of negatively or positively charged carbon nanotubes (CNTs) and hydrophobic microfiltration membranes by vacuum filtration. The thickness of the hydrophilic CNT coating is thus well-controlled by engineering the amount of CNTs deposited on the substrate membrane. The prepared Janus membranes are effective for the separation of both heavy oil and light oil from O/W emulsions through deemulsification owing to the charge-screening effect. It is very interesting that those membranes displaying a combination of water contact angle and underwater oil contact angle both above 90° have a unique oil delivery behavior and thus high separation performance of oil from O/W emulsions. Such Janus membranes can retrieve 89% of oil in 40 min from the 1,2-dichloroethane/water emulsions with the droplet size of 19 µm. This easy-to-prepare and easy-to-tune strategy provides feasibilities for practical applications of Janus membranes to the deemulsification and separation of O/W emulsions.

Janus Membranes with Opposing Surface Wettability Enabling Oil-to-Water and Water-to-Oil Emulsification.

A Janus membrane with opposing wettability was first reported with both function of water-to-oil and oil-to-water emulsification. This membrane is conveniently fabricated by single-surface deposition of polydopamine/polyethylenimine (PDA/PEI). The asymmetric wettability can also reduce the transmembrane resistance during the process, indicating an economical and promising strategy to prepare various emulsions. This research opens a novel avenue for exploring and understanding the Janus membrane, and provides a perspective to design the asymmetric membrane structures with promoted performance in conventional membrane processes.