Green Nanocellulose/PEI-Grafted Magnetic Nanoparticles for Effective Removal of Heavy Metal Ions.

In response to the pressing issue of water pollution caused by heavy metal ions, there is a growing demand for green adsorbents that can effectively remove these contaminants while being easy to separate and regenerate. A novel magnetic composite was synthesized by bonding amino-functionalized Fe3 O4 -SiO2 magnetic particles (MNP-NH2 ) to polyethyleneimine (PEI)-grafted cellulose nanofibers (CNF). The modification of CNF with PEI through a peptidic coupling reaction resulted in the uniform dispersion and strong attachment of MNP-NH2 particles (286.7 nm) onto the PEI-CNF surface. This composite exhibited exceptional adsorption capabilities for heavy metals, achieving 16.73 mg/g for Pb, 16.12 mg/g for Cu, and 12.53 mg/g for Co. These remarkable adsorption capacities are attributed to the complex interactions between the metal ions and the amino, carboxyl, and hydroxyl groups on the surface of PEI-CNF-MNP. The introduction of PEI significantly enhanced the adsorption capacities, and the adsorption sequence (Pb(II)>Cu(II)>Co(II)) can be explained by differences in ionic radius and surface complexation strength. Langmuir isotherm and pseudo-second-order kinetic models described the adsorption process, while Na2 EDTA was proved effective for desorption with high recovery rates. This magnetic composite holds promise for treating heavy metal-contaminated wastewater due to its impressive performance.

Facile Fabrication of Lignin-Cellulose Green Nanogels.

There has been increasing exploration of the development and production of biodegradable polymers in response to issues with petrol-based polymers and their impact on the environment. Here we report a new approach to synthesize a natural nanogel from lignin and nanocellulose. First, lignin nanobeads were synthesized by a solvent-shifting method, which showed a spherical shape with a diameter of 159.7 nm. Then the lignin nanobeads were incorporated into a nanocellulose network to form the lignin/cellulose nanogels. The nanocellulose fibrils (CNF-C) nanogels reveal a higher storage modulus than the nanocellulose crystal (CNC-C) ones due to the denser network with self-entanglement of longer cellulose chains. The presence of lignin nanobeads in the nanogels helped to increase the viscoelasticity of the nanogels. This work highlights that the new kinds of green nanogels could be potentially utilized in a variety of biomedical applications such as drug delivery and wound dressing.

Quantification of aflatoxin B1 in vegetable oils using low temperature clean-up followed by immuno-magnetic solid phase extraction.

In the present study, a convenient and highly efficient method was developed to quantify aflatoxin B1 (AFB1) in oil samples. Low temperature clean-up (LTC) followed by immuno magnetic solid phase extraction (IMSPE) was used to clean up oil samples. LTC assisted in freezing out the interference from the oil matrix while IMSPE further helped to preconcentrate the targeted analyte. For IMSPE, we synthesised and characterised anti-AFB1 monoclonal antibody-functionalised magnetic nanoparticles. Oil sample extraction was then carried out using LTC-IMSPE. The proposed method showed satisfactory efficiency and reproducibility with recovery rates being within the range of 79.6-117.9%, with a relative standard deviation below 11.48%. The sensitivity of the method was satisfactory with the limits of detection and quantification being as low as 0.0048 and 0.0126 ng·g-1, respectively. Real sample analysis was carried out for five kinds of different vegetable oils. The results suggest that the method developed is very sensitive and accurate.

Aluminium alloyed iron-silicide/silicon solar cells: A simple approach for low cost environmental-friendly photovoltaic technology.

This work demonstrates the fabrication of silicide/silicon based solar cell towards the development of low cost and environmental friendly photovoltaic technology. A heterostructure solar cells using metallic alpha phase (α-phase) aluminum alloyed iron silicide (FeSi(Al)) on n-type silicon is fabricated with an efficiency of 0.8%. The fabricated device has an open circuit voltage and fill-factor of 240 mV and 60%, respectively. Performance of the device was improved by about 7 fold to 5.1% through the interface engineering. The α-phase FeSi(Al)/silicon solar cell devices have promising photovoltaic characteristic with an open circuit voltage, short-circuit current and a fill factor (FF) of 425 mV, 18.5 mA/cm(2), and 64%, respectively. The significant improvement of α-phase FeSi(Al)/n-Si solar cells is due to the formation p(+-)n homojunction through the formation of re-grown crystalline silicon layer (~5-10 nm) at the silicide/silicon interface. Thickness of the regrown silicon layer is crucial for the silicide/silicon based photovoltaic devices. Performance of the α-FeSi(Al)/n-Si solar cells significantly depends on the thickness of α-FeSi(Al) layer and process temperature during the device fabrication. This study will open up new opportunities for the Si based photovoltaic technology using a simple, sustainable, and los cost method.

A plasmonic nanosensor with inverse sensitivity for circulating cell-free DNA quantification.

A plasmonic nanosensor (using gold nanorods) with inverse sensitivity is presented for circulating cell-free DNA quantification. The inverse sensitivity (i.e. the lower the analyte concentration, the higher the response intensity) is achieved by the unusual DNA concentration-dependent gold nanorod aggregation. This assay method can adjust the dynamic range by controlling the concentration of nanoparticles in solution.