Graphdiyne chelated AuNPs for ultrasensitive electrochemical detection of tyrosine.

Tyrosine (Tyr) is a kind of amino acid that can regulate emotions and stimulate the nervous system, and it is of great importance to realize its ultrasensitive detection. A unique material of graphdiyne chelated AuNPs (GDY@AuNPs) is designed and developed to realize high-performance electrochemical sensing of Tyr. GDY promotes the absorption of Tyr via π-π interaction, and its CC strongly chelates with AuNPs for greatly improved sensitivity. GDY@AuNPs delivers a sensitivity of up to 181.2 µA mM-1 cm-2 and a wide range of 0.1-600 µM, among the best for carbon or AuNPs-based materials for the detection of Tyr. It demonstrates the accurate detection of Tyr in human sweat for potential practical applications.

Nutrient removal efficiency in a rice-straw denitrifying bioreactor.

Rice straw was used as a carbon source in a denitrifying bioreactor, for the removal of nutrients from agricultural drainage. Nutrient removal efficiency was evaluated by: (a) nutrient loading rates (low, medium, and high); (b) hydraulic retention time, and (c) comparison with another carbon source (woodchip). The results show that concentrations of nitrate nitrogen (NO3(-)-N), ammonia nitrogen (NH4(+)-N), total nitrogen (TN), and orthophosphate phosphorus (PO4(3-)-P) in the rice-straw bioreactor effluents were reduced by 53%, 25%, 40%, and 35%, respectively, compared with influents at the medium nutrient loading rate (NO3(-)-N: 10-15 mg N L(-1), NH4(+)-N: 10-15 mg N L(-1), PO4(3-)-P: 1.0-1.5 mg P L(-1)) and long hydraulic retention time (HRT, 24h), with a corresponding denitrification rate (DR) of 0.40 mg N L(-1)h(-1). Moreover, the rice-straw bioreactor showed significantly higher (p<0.05) nutrient removal efficiency than the woodchip bioreactor at the medium nutrient loading rate and 24h HRT.