Size-controlled synthesis of CdS nanoparticles confined on covalent triazine-based frameworks for durable photocatalytic hydrogen evolution under visible light.

CdS nanoparticle-decorated covalent triazine-based frameworks (CdS NPs/CTF-1) were controllably synthesized via a facile one-pot solvothermal method. Due to the Lewis basic nature of well-defined nitrogen sites in triazine units of CTF-1, highly dispersed and size-controlled CdS NPs were obtained and stabilized on the surface of CTF-1 layers. The as-prepared CdS NPs/CTF-1 assembly showed higher photocatalytic activity in a hydrogen evolution reaction under visible light irradiation as compared with pure CdS and CTF-1 and their physical mixture. The superior photocatalytic performance observed over CdS NPs/CTF-1 was ascribed to the highly dispersed CdS NPs with strong interaction to CTF-1 layers. The strong NP-on-layer interactions between CdS and CTF-1 in the CdS NPs/CTF-1 assembly can not only facilitate the photogenerated charge separation rates, but can also shape CdS with a nanosized structure and high stability. This study develops a new strategy to improve the photocatalytic performance and conquer the photocorrosion of CdS, and also provides some guidance for us in the development of other CTF-incorporated nanocomposite photocatalysts.

[Application of biotic ligand model for the acute toxicity of copper to Daphnia magna in water of Liaohe River and Taihu Lake].

The acute toxicity (48 h-LC50 ) of copper to Daphnia magna predicted by the biotic ligand model (BLM) was compared with the 48 h-LC50 measured in water samples from Liaohe River and Taihu Lake at four specific sites in wet and dry seasons. The results showed that 48 h-LC50 values predicted by BLM were 232.75-411.49 microgL-1 and 48 h-LC50 values measured in the water samples were 134. 55-350. 00 microg L-1 in three sites of Hongmiaozi of Liaohe River, Pingtaishan and Tuoshan of Taihu Lake, which had a better consistency. While for Tongjiangkou of Liaohe River, there was a difference between the BLM predictions and the measured values in wet and dry seasons. According to the predictions and the experimental results, water effect ratios (WERs) were in the range of 2. 18-5.79 and 1.88-11.15 which all were higher than 1. The acute toxicity of Cu of all sites in dry season was greater than those in wet season, which might be that Cu complexation with dissolved organic matter (DOC) reduced the toxicity of Cu.