本文關(guān)鍵詞：膠州灣大沽河口潮灘重金屬分布機(jī)理室內(nèi)模擬實(shí)驗(yàn)研究　出處：《中國(guó)地質(zhì)大學(xué)(北京)》2017年碩士論文　論文類(lèi)型：學(xué)位論文

  更多相關(guān)文章： 河口 重金屬 鐵 鉻 Zeta電位

【摘要】：膠州灣屬半封閉海灣,有相對(duì)獨(dú)立的自然條件。大沽河為膠州灣最大河流,其河口屬于封閉程度較高的海灣河口潮間帶類(lèi)型,是開(kāi)展潮間帶調(diào)查的理想場(chǎng)所。本文通過(guò)相關(guān)性分析得出:Fe是影響河口潮灘重金屬分布的最主要因素,并選擇與Fe相關(guān)性最高的重金屬Cr共同作為研究對(duì)象。通過(guò)實(shí)驗(yàn)室模擬實(shí)驗(yàn),探究在pH和鹽度顯著變化的河口地區(qū)Fe對(duì)于Cr分布的影響;并輔以XRD、SEM-EDS、XPS的表征手段,為河口區(qū)沉積物重金屬分布影響機(jī)理提供科學(xué)依據(jù)。得出如下結(jié)論:(1)由于pH增大和鹽度提高,進(jìn)入河口地區(qū)的鐵會(huì)發(fā)生水解,并完全生成氫氧化鐵;Fe的水解速率隨pH的增大而增大,而受鹽度的影響不大。(2)河口區(qū)近河水端向近海水端過(guò)渡,pH從弱酸性向弱堿性過(guò)渡,氫氧化鐵對(duì)于鉻的去除率隨pH增大而減小;這是由pH改變氫氧化鐵的Zeta電位引起的。(3)河口區(qū)近河水端向近海水端過(guò)渡,鹽度由0變化到30的過(guò)程中,氫氧化鐵對(duì)鉻的去除率先降低后增加。由于Na+進(jìn)入氫氧化鐵膠體滑動(dòng)面使Zeta電位升高,膠體穩(wěn)定性提高,因膠體聚沉卷吸過(guò)程被去除的Cr減少,同時(shí)Cl-與CrO42-/HCrO4-形成競(jìng)爭(zhēng)吸附,因而鹽度為10組的Cr去除率僅不到10%。(4)河口區(qū)生成的氫氧化鐵會(huì)經(jīng)歷絮體生成,絮體生長(zhǎng)以及絮體變小三個(gè)階段,鹽度越大,生成絮體的速度越快,粒徑越大,絮體之間的結(jié)合更緊密越不容易進(jìn)入絮體變小階段,且絮體變小后的顆粒粒徑越大,分布越均勻。(5)Cr(Ⅵ)通過(guò)靜電引力吸附到氫氧化鐵絮體表面,Cr(Ⅲ)通過(guò)卷吸進(jìn)入絮體內(nèi)部和共沉淀在絮體表面被去除,卷吸進(jìn)絮體內(nèi)部的鉻會(huì)因絮體變小釋放出來(lái),不易生成Fe-Cr氧化物或氫氧化物。
[Abstract]:Jiaozhou Bay is a semi-closed bay with relatively independent natural conditions. The Dagu River is the largest river in Jiaozhou Bay, and its estuary belongs to the intertidal zone type of estuary with higher closure degree. It is an ideal place to carry out intertidal investigation. Through the correlation analysis, it is concluded that: Fe is the most important factor affecting the distribution of heavy metals in estuarine tidal flat. The heavy metal Cr which has the highest correlation with Fe was chosen as the research object. The effects of Fe on the distribution of Cr in estuaries where pH and salinity changed significantly were investigated by laboratory simulation experiments. With the help of XRDX SEM-EDSU XPS, this paper provides a scientific basis for the distribution mechanism of heavy metals in sediment in the estuary. The conclusion is as follows: (1) because of the increase of pH and salinity. Iron entering the estuary area will hydrolyze and form iron hydroxide completely. The hydrolysis rate of Fe increases with the increase of pH, but is not affected by salinity. The removal rate of chromium from ferric hydroxide decreases with the increase of pH. This is caused by the change of Zeta potential of ferric hydroxide in the estuary. The transition from the end of the river to the near end of the sea water and the change of salinity from 0 to 30. The removal of chromium by ferric hydroxide firstly decreased and then increased. Because Na entered the sliding surface of ferric hydroxide colloid, the potential of Zeta increased, the stability of colloid increased, and the Cr removed by colloid entrainment process decreased. At the same time, Cl- and CrO42--HCrO4- form competitive adsorption, so the Cr removal rate of 10 groups of salinity is less than 10%) the ferric hydroxide formed in the estuary will undergo floc formation. In the three stages of floc growth and flocs becoming smaller, the higher the salinity, the faster the speed of floc formation, the larger the particle size, the closer the combination between the floc is, the less easy it is to enter the floc becoming smaller stage. The larger the particle size of the flocs is, the more uniform the particle size is, and the more uniform the particle size is, the more uniform the particle size is. The surface of Fe (OH) _ 3 floc is adsorbed by electrostatic gravity. The Cr (鈪，

本文編號(hào)：1414638