Water environment

About: Water environment is a research topic. Over the lifetime, 13384 publications have been published within this topic receiving 125138 citations.

Ion exchange induced removal of Pb(ii) by MOF-derived magnetic inorganic sorbents.

Abstract: Nanoporous adsorbents of ZnO/ZnFe2O4/C were synthesized by using a metal organic framework (Fe(III)-modified MOF-5) as both the precursor and the self-sacrificing template. The adsorption properties of ZnO/ZnFe2O4/C toward Pb(ii) ions were investigated, including the pH effect, adsorption equilibrium and adsorption kinetics. The adsorption isotherms and kinetics were well described by using the Langmuir isotherm model and pseudo-second-order model, respectively. The MOF-derived inorganic adsorbents exhibited high absorption performance with a maximum adsorption capacity of 344.83 mg g(-1). X-ray powder diffraction and high-resolution X-ray photoelectron spectroscopy suggest that Zn(ii) was substituted by a significant portion of Pb(ii) on the surface of ZnO nanocrystals. Microscopic observations also demonstrate the effect of Pb(ii) ions on ZnO crystals as reflected by the considerably reduced average particle size and defective outer layer. Quantitative measurement of the released Zn(ii) ions and the adsorbed Pb(ii) ions indicated a nearly linear relationship (R(2) = 0.977). Moreover, Pb-containing ZnO/ZnFe2O4/C adsorbents are strongly magnetic allowing their separation from the water environment by an external magnet.

Effectiveness of Water Exercise on Postural Mobility in the Well Elderly: An Experimental Study on Balance Enhancement

Abstract: BACKGROUND The fear of falling may cause elderly people to limit their movement. As movement errors are known to facilitate the acquisition of motor skills, the elderly may inadvertently cause the loss of postural skills by constraining their movements, and hence avoid potential movement errors. It was hypothesized that by having elderly individuals exercise in a risk-free environment-water was utilized in this experiment-their postural capabilities would improve. METHODS Four groups of elderly subjects (80 +/- 5.8 years old) were placed into four groups: Water Exercisers; Land Exercisers; Water Sitters; and Land Sitters. Each group met twice per week for 45 minutes for 5 weeks of simple exercises or socializing in the designated medium. The distance each individual could reach (Functional Reach, FR) was measured at the end of each week. RESULTS Initially, each group was at risk (FR < 10 inches) for falling Statistical testing showed that the Water Exercisers (WE) increased their FR almost every week; the Land Exercisers (LE) increased only during the first week; and the Water Sitters (WS) and Land Sitters (LS) did not increase at all. The FRs after 5 weeks were 13.4 +/- 1.6 (WE), 11.3 +/- 1.5 (LE), 9.6 +/- 1.3 (WS), and 9.3 +/- 0.71 (LS) inches for each group, respectively. CONCLUSIONS The data showed that the postural capabilities in these elderly people, as measured by the FR, were enhanced by the production of movement errors that was facilitated in a water environment (in the case of the Water groups) or the initiation of a novel exercise program (Land Exercisers). Alternative explanations, and implication of these results, are discussed.

Impact of Water Projects on River Flow Regimes and Water Quality in Huai River Basin

Abstract: Research on the impact of water projects (dams or floodgates) on river hydrology and the surrounding environment is important in river basin management. However, it is a difficult scientific issue due to its complexity. Huai River Basin is a unique region in China with high densities in both population and water projects and is experiencing a serious pollution problem. Based on the extended SWAT model with consideration of dams & floodgates, this paper proposes a quantitative framework to assess the impact of dams & floodgates on the river flow regimes and water quality in the middle and upper reaches of Huai River Basin. The results show that: (1) The dams & floodgates reduced the basin's annual average flow by 2%, in comparison with the scenario of no water projects in the whole basin during 1991-2000, because of the regulation and storage of dams & floodgates. The flow in the non-flood season reduced 5% while the change of flow in the flood season was not acute. The impact of dams & floodgates on the annual flow are different in wet and dry years. In the wet year (1991), the impact of dams & floodgates is not obvious because the gates were opened to control the floods and their main functions are to change the temporal distribution in a year. In the dry year (1999), the flow reduced remarkably in comparison with the flow without dams & floodgates in the basin because the gates were closed in order to meet the water demand. The flow in the flood season increased by 8% whiles the flow in the non-flood season reduced by 12%. (2) There was a certain impact of dams & floodgates on water quality but they were quite different in the different area. It would be changed from the positive effect to the negative effect from the upriver to downstream. The dams & floodgates in the upper reaches played a positive role to improve water quality. But the ones in the middle and lower reaches played a negative role with contribution from 0 to 0.4. However, the contribution of exceeding pollutant discharge was more than 0.6. (3) The joint operation of dams & floodgates to control water quantity and quality will improve the water environment in Huai River Basin, but the key to improve the basin's water environment is pollution control. This research will guide the anti-pollution and the united water quantity and quality assessment of dams & floodgates in Huai River Basin. Moreover it will provide a foundation to achieve the integrated basin management and sustainability of Huai River Basin.