[Community Structure Characteristics of Diatom in Reservoirs Located in the South of Jiangsu Province, China and Its Control Factors].

In order to understand the community structure characteristics of Bacillariophyta and its controlling factors in reservoirs located in the Southeast, China, in the geographic background of hills landscape and humid climate, 18 reservoirs were investigated in June, 2015, during the period with high risk of diatom bloom, covering water quality, and the community structures of phytoplankton. The correlations between Bacillariophyta and other planktons with nutrients, water depth, storage capacity, etc. were analyzed. The results showed that, 10 reservoirs reached the light extent of diatom bloom ( density between 100 x 104-1,000 x 104 cells · L⁻¹ reservoirs in this area were generally in mesotrophic or eutrophic state with considerably high total nitrogen concentrations; total phosphorus and trophic level index were both closely correlated with Bacillariophyta biomass. Phormidium in Cyanophyta was the dominating generus among phytoplankton in terms of density; with respect to biomass, Bacillariophyta, Chlorophyta and Cyanophyta were the top three phylum, and Bacillariophyta accounted for 46. 8% of the total phytoplankton biomass, becoming the most important one resulting in abnormal propagation of algae; Synedra (51.5%) and Cyclotella (21.4%) were the main dominating genera in Bacillariophyta, together with Achnanthes and Melosira. Deep water was favored by Bacillariophyta to dominate among different phyla. Larger ratio between catchment and reservoir storage capacity, on the other hand, caused the increase of trophic level and chlorophyll, and benefited the shift of dominating phytoplankton from Bacillariophyta to Chlorophyta and Cyanophyta, by which, the risk of algae bloom would be increased. It reveals that to alleviate the risk of algae bloom and protect drinking water resources, catchment management is crucial for the studied reservoirs. And the establishment of nutrient reduction strategies needs to consider the features of each individual reservoir, i. e. water depth, ratio between catchment and capacity.

[Adsorption of humic acid onto aminated HMS].

The adsorption of humic acid onto hexagonal mesoporous silica(HMS) and surface aminated HMS was investigated. The simulation results using Freundlich model indicated that the surface amination of HMS led to an increase of adsorption constant from 0.56 to 105, reflecting markedly enhanced adsorption of humic acid upon surface amination. In addition, humic acid adsorption under acidic conditions was favored. Adsorbed humic acid molecules were found to be located in the mesopores of aminated HMS and the mesopores with relatively larger pore diameters were preferentially occupied. The kinetics of humic acid adsorption onto the aminated HMS could be well described by second order kinetics and the adsorption rate was mainly dominated by intrapore diffusion process.

Adsorption equilibria and kinetics for phenol and cresol onto polymeric adsorbents: effects of adsorbents/adsorbates structure and interface.

Phenol and cresol (o-, m-, and p-) were selected as the adsorbates with different dipole moment (cresol>phenol, methyl being electron-drawing group) and solubility (phenol>cresol, methyl being hydrophobic group). Macropore polymers (NDA-1800 and XAD-4), hypercrosslinked polymers (NDA-100), and chemically modified adsorbents (NDA-150 and NDA-99), were comparatively used to investigate the adsorption properties including equilibria, thermodynamics and kinetics. First, all of the results about equilibria show that the adsorption data fit well to the Freundlich model. The adsorption capacity of NDA-99 and NDA-150 especially for phenol is larger in a certain extent than other three types of polymers. The hydrophobic interaction from large specific surface was mainly occurred, while the polar groups containing oxygen and amine markedly enhance the adsorption process via hydrogen interaction. Furthermore, the adsorption amount for NDA-99 and XAD-4 decrease linearly with the solubility of solutes tested. Then, the negative values of enthalpy demonstrate the predominantly exothermic and physical solid-extraction processes. Finally, the relatively more rapid adsorption process could be found onto NDA-150 than NDA-99, with the reason of the double larger pore size of the former. In conclusion, solubility of solute, together with surface area, pore size and modified groups, extremely exerts influences to the adsorption performances.