Spontaneous Deposition of Uniformly Distributed Ruthenium Nanoparticles on Graphitic Carbon Nitride for Quantifying Electrochemically Accumulated H_(2)O_(2)

Highly dispersed ultrasmall ruthenium nanoparticles with a clean surface are deposited onto graphitic carbon nitride(C_(3)N_(4)-Ru)through spontaneous redox reaction between the C_(3)N_(4) sheets and Ru salt without the use of any reductant.The as-prepared C_(3)N_(4)-Ru exhibits distinct peroxidase-like activity.A nanozyme based method is successfully developed for detecting the H_(2)O_(2) generated in-situ by the two-electron oxygen reduction strategy.The C_(3)N_(4)-Ru nanozyme can realize the detection of H_(2)O_(2) with a wide linear range and a low detection limit.The testing results are also compared with the conventional modified titration method,and show greater possibility for the practical detection of H_(2)O_(2) produced via the electrochemical oxygen reduction for its higher selectivity.

Selective elimination of chromophoric and fluorescent dissolved organic matter in a full-scale municipal wastewater treatment plant

Effluent organic matter（Ef OM） from municipal wastewater treatment plants potentially has a detrimental effect on both aquatic organisms and humans.This study evaluated the removal and transformation of chromophoric dissolved organic matter（CDOM） and fluorescent dissolved organic matter（FDOM） in a full-scale wastewater treatment plant under different seasons.The results showed that bio-treatment was found to be more efficient in removing bulk DOM（in term of dissolved organic carbon,DOC） than CDOM and FDOM,which was contrary to the disinfection process.CDOM and FDOM were selectively removed at various stages during the treatment.Typically,the low molecular weight fractions of CDOM and protein-like FDOM were more efficiently removed during bio-treatment process,whereas the humic-like FDOM exhibited comparable decreases in both bio-treatment and disinfection processes.Overall,the performance of the WWTP was weak in terms of CDOM and FDOM removal,resulting in enrichment of CDOM and FDOM in effluent.Moreover,the total removal of the bulk DOM（P 〈 0.05） and the protein-like FDOM（P 〈 0.05） displayed a significant seasonal variation,with higher removal efficiencies in summer,whereas removal of CDOM and the humic-like FDOM showed little differences between summer and winter.In all,the results provide useful information for understanding the fate and transformation of DOM,illustrating that sub-fractions of DOM could be selectively removed depending on treatment processes and seasonality.

Effect of nitrogen/phosphorus concentration on algal organic matter generation of the diatom Nitzschia palea:Total indicators and spectroscopic characterization

Critical algal blooms in great lakes increase the level of algal organic matters（AOMs）,significantly altering the composition of natural organic matters（NOMs） in freshwater of lake.This study examined the AOM＇s characteristics of Nitzschia palea（N.palea）,one kind of the predominant diatom and an important biomarker of water quality in the great lakes of China,to investigate the effect of AOMs on the variation of NOMs in lakes and the process of algal energy.Excitation–emission matrix fluorescence（EEM） spectroscopy,synchronous fluorescence（SF） spectroscopy and deconvolution UV–vis（D-UV） spectroscopy were utilized to characterize AOMs to study the effects of nutrient loading on the composition change of AOMs.From results,it was revealed that the phosphorus is the limiting factor for N.palea＇s growth and the generation of both total organic carbon and amino acids but the nitrogen is more important for the generation of carbohydrates and proteins.EEM spectra revealed differences in the composition of extracellular organic matter and intracellular organic matter.Regardless of the nitrogen and phosphorus concentrations,aromatic proteins and soluble microbial products were the main components,but the nitrogen concentration had a significant impact on their composition.The SF spectra were used to study the AOMs for the first time and identified that the protein-like substances were the major component of AOMs,creating as a result of aromatic group condensation.The D-UV spectra showed carboxylic acid and esters were the main functional groups in the EOMs,with –OCH_3,–SO_2NH_2,–CN,–NH_2,–O– and –COCH_3functional groups substituting into benzene rings.

Single-Component Chemical Nose with a Hemicyanine Probe for Pattern-Based Discrimination of Metal lons

We report here a chemical nose utilizing the nonspecificity of a hemicyanine dye(probe P)containing three acetates and one depro-tonatable phenol groups.Unlike conventional pattern-based recognition that requires a combination of different probes,probe P alone is able to differentiate 9 different metals,generating distinctive absorption spectra and various patterns upon principle component analysis(PCA).River water samples and commercial mineral water samples were evaluated by the probe and were successfully distinguished.

Design, Synthesis, Photophysical Studies and Electrochemistry of Carbazole-, Oxadiazole-, and Oxadiazole-Triarylamine-Containing Rhenium(Ⅰ) Diimine Alkynyl Complexes

A series of rhenium(I)diimine alkynyl complexes with various electron-and hole-transporting moieties has been synthesized and characterized.Their electronic absorption,emission and electrochemical properties have also been studied.