ABSTRACT
Aerogels with low thermal conductivity and high adsorption capacity present a promising solution to curb water pollution caused by organic reagents as well as mitigate heat loss. Although aerogels exhibiting good adsorption capacity and thermal insulation have been reported, materials with mechanical integrity, high flexibility and shear resistance still pose a formidable task. Here, we produced bacterial cellulose-based ultralight multifunctional hybrid aerogels by using freeze-drying followed by chemical vapor deposition silylation method. The hybrid aerogels displayed a low density of 10-15 mg/cm3, high porosity exceeding 99.1 %, low thermal conductivity (27.3-29.2 mW/m.K) and superior hydrophobicity (water contact angle>120o). They also exhibited excellent mechanical properties including superelasticity, high flexibility and shear resistance. The hybrid aerogels demonstrated high heat shielding efficiency when used as an insulating material. As a selective oil absorbent, the hybrid aerogels exhibit a maximum adsorption capacity of up to approximately 156 times its own weight and excellent recoverability. Especially, the aerogel's highly accessible porous microstructure results in an impressive flux rate of up to 162 L/h.g when used as a filter in a continuous oil-water separator to isolate n-hexane-water mixtures. This work presents a novel endeavor to create high-performance, sustainable, reusable, and adaptable multifunctional aerogels.
Subject(s)
Cellulose , Gases , Adsorption , Freeze Drying , Hot TemperatureABSTRACT
Amorphous metal-organic framework (aMOF)-based materials have attracted considerable attention as an emerging class of nanomaterials. Herein, novel microorganisms@aMIL-125 (Ti) composites including yeast@aMIL-125 (Ti), PCC 6803@aMIL-125 (Ti), and Escherichia coli@aMIL-125 (Ti) composites were respectively synthesized by self-assembling aMOFs on the microorganisms' surface. The functional groups on the microorganisms' surface induced structural defects and participated in the formation of aMIL-125 (Ti) composites. Finally, the application of microorganisms@aMIL-125 (Ti) composites for the removal of glyphosate from aqueous solution was selected as a model reaction to illustrate their potential for environmental protection. The present method is not only economical but also has other advantages including ease of operation, environmentally friendly assay, and high adsorption. The maximum adsorption capacity of aMIL-125 (Ti) was 1096.25 mg g-1, which was 1.74 times that of crystalline MIL-125 (Ti). Therefore, the microorganisms@aMOFs composites will have broad application prospects in energy storage, drug delivery, catalysis, adsorbing toxic substances, sensing, encapsulating and delivering enzymes, and in other fields.
ABSTRACT
Due to growing food safety issues, developing economic, rapid, and sensitive strategies for food spoilage monitoring has attracted significant attention. Here, a Bacillus subtilis spore-based biosensor is presented for rapid, highly sensitive, visual biogenic amines detection. The biosensor is fabricated through biogenic amines-induced pH increase which inhibits the electron transfer between Cu ion sites within CotA-laccase on the spore surface, leading to decrease in catalytic oxidation activity towards the chromogenic substrates. The developed system integrated with smartphone analysis realized the on-site monitoring of histamine with a detection range of 0.17-120 mg L-1, and a detection limit of 0.17 mg L-1 (3σ). Moreover, the color change induced by histamine is observable by the naked eye. The smart biosensor was successfully applied for food freshness evaluation in raw meat samples, showing several advantages, including eco-friendliness, low cost, and high stability, meeting the demands of on-site monitoring in the food safety field.
