ABSTRACT
Freshwater shortage is becoming one of the most critical global challenges owing to severe water pollution caused by micropollutants and volatile organic compounds (VOCs). However, current purification technology shows slow adsorption of micropollutants and requires an energy-intensive process for VOCs removal from water. In this study, a highly efficient molecularly engineered covalent triazine framework (CTF) for rapid adsorption of micropollutants and VOC-intercepting performance using solar distillation is reported. Supramolecular design and mild oxidation of CTFs (CTF-OXs) enable hydrophilic internal channels and improve molecular sieving of micropollutants. CTF-OX shows rapid removal efficiency of micropollutants (>99.9% in 10 s) and can be regenerated several times without performance loss. Uptake rates of selected micropollutants are high, with initial pollutant uptake rates of 21.9 g mg-1 min-1 , which are the highest rates recorded for bisphenol A (BPA) adsorption. Additionally, photothermal composite membrane fabrication using CTF-OX exhibits high VOC rejection rate (up to 98%) under 1 sun irradiation (1 kW m-2 ). A prototype of synergistic purification system composed of adsorption and solar-driven membrane can efficiently remove over 99.9% of mixed phenol derivatives. This study provides an effective strategy for rapid removal of micropollutants and high VOC rejection via solar-driven evaporation process.
ABSTRACT
Recent advances have led to the development of intelligent drug-delivery systems such as microchips, micropumps, and soft devices with sensors; however, the facile preparation of transdermal and implantable systems modulable to various stimuli remains elusive. In addition, the use of a battery limits their wearable and implantable applications. Therefore, to overcome these disadvantages, we herein suggest a facile strategy to prepare electro-mechanochemically responsive soft gel composites with molecular gatekeeper-based nanocontainers. We found that a metal-phenolic coordination network can act as an efficient self-healable and adaptive gatekeeper in response to electrical and mechanical stimuli owing to the reversible dynamic bonds and adhesiveness to the silica surface. The porous channels of mesoporous silica nanoparticles are filled with guest molecules, and the exterior is wrapped with metal-tannic acid (TA) networks. Owing to the robustness of metal-phenolic network, the guest molecules are efficiently entrapped in the channels but released by electrical and ultrasound input. Voltage-dependent changes in the guest release rate provide control over the dosage on demand. The combination of hydrogel matrixes with the responsive nanocapsules enables the construction of a series of adaptive gel composites capable of successive guest release in response to electrical, ultrasound, electromechanical, and triboelectric stimuli. The Korsmeyer-Peppas model revealed that the release mechanism is non-Fickian, which indicates the presence of boundaries around the guest-loading channels (n = 0.739, R2 = 0.9574 when 2 V is applied). This study realized efficient platforms for active-type drug-delivery applications based on transdermal patches and implantable gels with remotely controllable release characteristics.
