本文選題：泥沙顆粒　切入點(diǎn)：泥沙吸附　出處：《重慶交通大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：泥沙是磷運(yùn)動(dòng)的主要載體,泥沙的運(yùn)動(dòng)對(duì)于磷的遷移和轉(zhuǎn)化有著重要影響,這種影響主要表現(xiàn)為泥沙對(duì)磷的吸附和解吸過程。只有合理地考慮了泥沙對(duì)磷的吸附解吸效應(yīng),才能正確的判斷磷運(yùn)動(dòng)的時(shí)空變化過程。由此,本文運(yùn)用明渠和數(shù)值模擬手段,模擬研究自然河流的流動(dòng)水體中泥沙與磷相互作用的動(dòng)態(tài)過程及其基本特性。為了較好的模擬自然條件下河流的流動(dòng)狀態(tài),本文采用循環(huán)流明渠模型,在使得泥沙隨系統(tǒng)水體一起參與循環(huán)的基礎(chǔ)上,分析并用泥沙吸附理論解釋了不同泥沙粒徑、泥沙濃度、水相磷初始濃度條件下泥沙對(duì)水體中磷的吸附過程并進(jìn)行了Elovich方程及二級(jí)動(dòng)力學(xué)方程的模擬。對(duì)比了現(xiàn)有搖瓶試驗(yàn)和明渠模型試驗(yàn)在試驗(yàn)結(jié)果和動(dòng)力學(xué)方程模擬上的區(qū)別。本文的研究有以下結(jié)論:在懸移質(zhì)泥沙與磷相互作用的過程中,隨著溶解態(tài)磷濃度的減小,吸附至泥沙上的顆粒態(tài)磷的濃度逐漸增加,在初始階段減小和增加的速率較大,隨著時(shí)間的推移這個(gè)速率慢慢降低,最后懸移質(zhì)泥沙與磷的相互作用達(dá)到一個(gè)動(dòng)態(tài)平衡。粒徑較小的泥沙顆粒的吸附能力比粒徑較大的泥沙顆粒的吸附能力強(qiáng)。泥沙對(duì)磷的吸附容量均隨著水體中含沙量的增大而增大。在水相磷初始濃度一定的條件下,隨著含沙量的增大,單位質(zhì)量的泥沙吸附磷的能力存在下降的趨勢(shì)。雖然單位質(zhì)量泥沙對(duì)磷的平衡吸附量隨含沙量的增大而減小,但是泥沙對(duì)于磷吸附容量反而隨著含沙量的增大而增大。這種特性對(duì)于研究水體中磷的自凈作用和水體水環(huán)境的容量具有重大意義。在相同含沙量、不同磷初始濃度條件下,泥沙對(duì)磷的吸附容量均隨著初始磷濃度的增大而增大。但隨著初始磷濃度的增加,泥沙對(duì)磷的吸附量占初始磷的比例越來(lái)越低。結(jié)論表明,泥沙對(duì)磷的吸附有利于降低水體中水相磷的濃度,但水體中磷的濃度越高,水體中泥沙的這種作用越小。本文采用明渠試驗(yàn),各組平衡時(shí)間均在2h左右。在模擬明渠模型中泥沙吸附磷動(dòng)力學(xué)過程方面,雖然Elovich方程模擬出方程相關(guān)度都在0.9左右,但與實(shí)際曲線仍有較大差別,而二級(jí)動(dòng)力學(xué)方程能夠較好的模擬明渠模型中泥沙吸附磷動(dòng)力學(xué)過程。相比而言,對(duì)與實(shí)際情況下的河流磷分布情況,二級(jí)動(dòng)力學(xué)方程有更好的指導(dǎo)意義。
[Abstract]:Sediment is the main carrier of phosphorus movement, and its movement has an important effect on the transport and transformation of phosphorus, which is mainly manifested in the process of phosphorus adsorption and desorption. In order to correctly judge the temporal and spatial changes of phosphorus movement, the open channel and numerical simulation are used in this paper. The dynamic process and basic characteristics of the interaction between sediment and phosphorus in flowing water of natural rivers are simulated. In order to better simulate the flow state of rivers under natural conditions, the open channel model of circulating flow is adopted in this paper. On the basis of making the sediment participate in the circulation with the system water body together, the different sediment particle size and sediment concentration are analyzed and explained by the sediment adsorption theory. The adsorption process of phosphorus in water by sediment under the initial concentration of phosphorus in aqueous phase was simulated by Elovich equation and second order kinetic equation. The experimental results and kinetic equations of the existing shaking flask test and open channel model test were compared. The conclusions of this study are as follows: in the process of interaction between suspended sediment and phosphorus, With the decrease of dissolved phosphorus concentration, the concentration of particulate phosphorus adsorbed to sediment increases gradually, and decreases and increases rapidly in the initial stage, and decreases slowly with the passage of time. Finally, the interaction between suspended sediment and phosphorus reached a dynamic equilibrium. The adsorption capacity of small sediment particles was stronger than that of larger sediment particles. The amount of sediment increases with the increase of the initial concentration of phosphorus in the water phase. With the increase of sediment content, the capacity of phosphorus adsorption by sediment per unit mass decreases, although the equilibrium adsorption capacity of sediment per unit mass decreases with the increase of sediment content. However, the adsorption capacity of sediment for phosphorus increases with the increase of sediment content, which is of great significance to the study of the self-purification of phosphorus in water and the capacity of water environment. The adsorption capacity of sediment to phosphorus increases with the increase of initial phosphorus concentration, but with the increase of initial phosphorus concentration, the proportion of phosphorus adsorbed by sediment to initial phosphorus becomes lower and lower. The adsorption of phosphorus by sediment can reduce the concentration of phosphorus in water, but the higher the concentration of phosphorus in water, the less the effect of sediment in water. The equilibrium time of each group is about 2 hours. In simulating the kinetic process of phosphorus adsorption by sediment in the open channel model, although the correlation degree of the equation simulated by Elovich equation is about 0.9, it is still quite different from the actual curve. The second-order kinetic equation can simulate the process of phosphorus adsorption in open channel model, which is more instructive to the distribution of phosphorus in rivers.
【學(xué)位授予單位】：重慶交通大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：X143;TV142

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