Highly efficient adsorption of Hg2+ from aqueous solutions by amino-functionalization alkali lignin.

Lignin, as a biodegradable byproduct of industry, has become popular in developing low-cost and high-performance heavy metal adsorbents. Herein, a high-efficiency novel adsorbent for mercury ion, amino-functionalization alkali lignin (AAL) was facile synthesized by one-step approach under very mild conditions. The as-prepared AAL was characterized by FT-IR, BET, XPS and SEM. The adsorption properties of AAL for Hg2+ were elucidated in batch system. The results showed that AAL exhibited exceptionally high adsorption capacity for Hg2+ at pH of 4- 6, the maximum adsorption capacity can reach 553.9 mg g-1. The remove efficiency could above 99% when dealing with 300 mg L-1 of Hg2+ solution at 30 °C using 1 g L-1 adsorbent. The adsorption was a spontaneous endothermic process. Pseudo-second-order kinetic and Langmuir isotherm model fitted well with the sorption data, which proposed the adsorption was a monolayer chemical adsorption process. The mechanism analysis demonstrated that nitrogen-containing functional groups of AAL were mainly contributed to the adsorption of Hg2+. Moreover, the adsorption capacity of the regenerated AAL could still be maintained at 91% by the fifth cycle. These findings demonstrated that AAL can provide an effective way to enhancing removal of Hg2+ from aqueous solutions.

High-Quality Ferromagnet Fe3GeTe2 for High-Efficiency Electromagnetic Wave Absorption and Shielding with Wideband Radar Cross Section Reduction.

A high-quality Fe3GeTe2 single crystal with good electrical, magnetic, and electromagnetic wave absorption and shielding properties was prepared in a large quantity (10 g level) by solid-phase sintering and recrystallization method, which would promote its in-depth research and practical application. It has good room-temperature electrical properties with a mobility of 42 cm2/V·s, a sheet (bulk) carrier concentration of +1.64 × 1018 /cm2 (+3.28 × 1020 /cm3), and a conductivity of 2196.35 S/cm. Also, a Curie temperature of 238 K indicates the high magnetic transition temperature and a paramagnetic Curie temperature of 301 K shows the large ferromagnetic-paramagnetic transition zone induced by the residual short-range ferromagnetic domains. Particularly, Fe3GeTe2 is in a loosely packed state when used as a loss agent; the electromagnetic wave absorption with a reflection loss of -34.7 dB at 3.66 GHz under thin thickness was shown. Meanwhile, the absorption band can be effectively regulated by varying the thickness. Moreover, Fe3GeTe2 in a close-packed state exhibits terahertz shielding values of 75.1 and 103.2 dB at very thin thicknesses of 70 and 380 µm, and the average shielding value is higher than 47 dB, covering the entire bandwidth from 0.1 to 3.0 THz. Furthermore, by using Fe3GeTe2 as a patch, the wideband radar cross-section can be effectively reduced by up to 33 dBsm. Resultantly, Fe3GeTe2 will be a promising candidate in the electromagnetic protection field.

DNA-induced synthesis of biomimetic enzyme for sensitive detection of superoxide anions released from live cell.

In this work, we successfully fabricate a rapid, sensitive sensor for the detection of superoxide anions O2˙- based on graphene/DNA/Mn3(PO4)2 biomimetic enzyme. In the design, graphene is served as excellent carrier to improve the catalysis of Mn3(PO4)2 nanoparticles; and DNA adsorbed on graphene acts as medium to assist the growth of Mn3(PO4)2 on graphene. The fabricated graphene/DNA/Mn3(PO4)2 composites exhibit excellently electrochemical activity, significantly decrease the response time and increase the sensitivity of the sensor towards O2˙-. The successful detection of O2˙- released from cancer cell demonstrated its potential applications in biology and medicine.

Hierarchical Nafion enhanced carbon aerogels for sensing applications.

This work describes the fabrication of hierarchical 3D Nafion enhanced carbon aerogels (NECAGs) for sensing applications via a fast freeze drying method. Graphene oxide, multiwalled carbon nanotubes and Nafion were mixed and extruded into liquid nitrogen followed by the removal of ice crystals by freeze drying. The addition of Nafion enhanced the mechanical strength of NECAGs and effective control of the cellular morphology and pore size was achieved. The resultant NECAGs demonstrated high strength, low density, and high specific surface area and can achieve a modulus of 20 kPa, an electrical conductivity of 140 S m(-1), and a specific capacity of 136.8 F g(-1) after reduction. Therefore, NECAG monoliths performed well as a gas sensor and as a biosensor with high sensitivity and selectivity. The remarkable sensitivity of 8.52 × 10(3)µA mM(-1) cm(-2) was obtained in dopamine (DA) detection, which is two orders of magnitude better than the literature reported values using graphene aerogel electrodes made from a porous Ni template. These outstanding properties make the NECAG a promising electrode candidate for a wide range of applications. Further in-depth investigations are being undertaken to probe the structure-property relationship of NECAG monoliths prepared under various conditions.