| Phosphorus is the restrictive element of lake eutrophication and the focus problem when research the eutrophication. As the longest river running into the Baiyangdian Lake, the Fu River has delivered amount of phosphorus. Researches on the phosphorus distribution in the river are essential to control pollution of the lake. This study focused on determining the distribution characteristics of phosphorus in the river. Moreover, the adsorption capacity, influencing factors and the mechanism of some adsorbent material and its modified were investigated. Main conclusions were achieved as follows:(1) Water quality of the Fuhe River in the recent year was monitored continuously, which was worse than that required by Criteria V (GB3838-2002). The river is characterized as containing high phosphorus and low DO. The concentrations of total phosphorus and DO of the river are0.83-4.14mg/L and1.16-7.67mg/L. The highest concentrations of phosphorus turn up in low-flow period, and followed by average-flow period and high-flow period. DO with a significant negative correlation of phosphorus in water, and TOC is not associated with the phosphorus in water.(2) Different forms of phosphorus in sediment of Fuhe River were extracted by the method of SMT. The level of inorganic phosphorus in sediments of Fuhe River is usually a litter higher than that of organic phosphorus; The level of phosphorus in sediments of shaoche area is obviously lower than that in other sampling points. As same as phosphorus in water, the highest concentrations of phosphorus in sediment turn up in low-flow period, and followed by average-flow period and high-flow period. Organic phosphorus and Fe/Al-P with a significant negative correlation of phosphorus in water.(3) The Fuhe River is very dirty water, and the total bacterial are all more than1×105CFU/mL. The number of bacterial in sediment was significantly higher than in water. As the bacterial in water, the general trend of bacterial in sediment are showing decreased from upstream to downstream. The content of OPB is higher than the IPB. The phosphate-dissolving bacteria in sediment mainly belong to Bacillus, Agrobacterium, Staphylococcus, Acinetobacter.(4) The capacity of natural zeolite, fly ash, red mud, diatomaceous earth, iron-aluminum mud and the modified adsorbents (iron-aluminum mud modified with hydrochloric acid, fly ash and red mud modified with ferric chloride) for phosphorus adsorption were compared. The results indicate that the order of the phosphorus adsorption is as followed:modified red mud> modified fly ash> modified iron-aluminum> iron-aluminum> red mud and fly ash> natural zeolite> diatomaceous earth. The adsorption capacity of the modified adsorbents is obviously improved.(5) The effects of PH, temperature, other ions in water, small molecule organic acid and DOM in sediment of FuHe River on phosphorus adsorption by the modified red mud, modified fly ash and modified iron-aluminum were investigated. The results indicate that the adsorption number will be the best when PH=7; the optimum adsorption temperature is25-35℃; the adsorption capacity of phosphorus can be inhibited by HCO3-and SO42-, but the effect of Cl-and NO3-on phosphorus adsorption is insignificant. The adsorption capacity of modified iron-aluminum mud can be inhibited by oxalic acid and citric acid. The adsorption capacity of modified red mud can be improved by oxalic acid but inhibited by citric acid. DOM can promote the adsorption of phosphorus. The mechanism of these influencing factors were investigated, The results indicate that the Zeta potential of the modified red mud, modified fly ash and modified iron-aluminum mud is increased. Oxalic acid and citric acid can promote the dissolution of iron and aluminum in the surfaces of modified iron-aluminum mud, iron and aluminum in the surfaces of modified red mud can dissolve with the condition of citric acid, by not with oxalic acid. The DOM can raise the Zeta potential of the modified red mud and modified iron-aluminum mud. |
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