本文選題：土壤 + 鈾污染�。� 參考：《東華理工大學》2017年碩士論文

【摘要】：本文以南方某尾礦庫周邊土壤為研究對象,通過實驗測定研究區(qū)周邊土壤pH值、含水量、有機質(zhì)、CEC等理化性質(zhì),通過靜態(tài)吸附實驗,考察了初始pH、初始鈾濃度、吸附時間及有機質(zhì)等因素對土壤吸附鈾的影響,通過動態(tài)遷移實驗,考察了不同淋濾量及pH值下鈾在土壤中遷移轉(zhuǎn)化及形態(tài)分布特征,并通過對實驗數(shù)據(jù)擬合探討土壤吸附鈾的機理。主要結(jié)論如下:(1)研究區(qū)土壤樣品pH為4.63,呈酸性;含水率為1.39%,含水率偏高;有機質(zhì)含量為46.98g/kg;陽離子交換量(CEC)為46.98cmol/kg;總鈾的含量為3.21μg/g,屬于鈾污染土壤。(2)靜態(tài)吸附實驗研究表明:初始pH、初始鈾濃度、吸附時間、有機質(zhì)、磷酸鹽、土壤粒徑這幾種因素對土壤吸附鈾的影響極其顯著;重金屬離子中Cu、Cd、Pb、Zn抑制土壤對鈾的吸附,K基本不影響土壤對鈾的吸附;在常溫下,溫度對土壤吸附鈾的能力沒有顯著的影響。在吸附溫度為25℃條件下,100目的土壤樣品0.5g,在初始pH為5.0,吸附時間達8h以上,初始鈾濃度為10mg/L的條件下,吸附率達到最大值,吸附率為96.36%,吸附量為0.1927mg/g。(3)動態(tài)遷移實驗研究表明:經(jīng)不同淋濾量及不同pH淋濾液淋濾后,淋濾量與pH的不同使鈾在土壤中遷移不同的距離,鈾在土壤中的形態(tài)分布規(guī)律為殘渣態(tài)無定型鐵錳氧化物/氫氧化物結(jié)合態(tài)碳酸鹽結(jié)合態(tài)有機質(zhì)結(jié)合態(tài)可交換態(tài)(包括水溶態(tài))晶質(zhì)鐵錳氧化物/氫氧化物結(jié)合態(tài),且土壤中殘渣態(tài)鈾及無定型鐵錳氧化物/氫氧化物結(jié)合態(tài)鈾均略高于原土壤,晶質(zhì)鐵錳氧化物/氫氧化物結(jié)合態(tài)鈾含量占比均為最小,其余三種形態(tài)鈾分布不均。(4)吸附機理分析研究表明:土壤樣品吸附前后結(jié)構(gòu)保持相對完整,土壤表面形貌特征發(fā)生一定變化,土壤表面存在著大量的C-N、C-O、C-H等帶有負電荷的官能團,增強土壤對鈾酰離子的靜電吸附能力。土壤對鈾的吸附過程以單分子層吸附為主,多分子層吸附、物理吸附和化學吸附并存,以Langmuir等溫吸附模型(R2=0.9954)、準二級吸附動力學模型(R2=0.9977)來描述其吸附過程較為合適,且該吸附過程為放熱過程可自發(fā)進行。
[Abstract]:In this paper, the physical and chemical properties of the soil around a tailings reservoir in the south of China were studied. The physical and chemical properties of the soil such as pH value, water content, organic matter CEC and so on were determined by experiments. The initial pH and initial uranium concentration were investigated by static adsorption experiment. The effects of adsorption time and organic matter on the adsorption of uranium in soils were studied by dynamic migration experiments. The migration, transformation and morphological distribution of uranium in soils with different leaching amounts and pH values were investigated. The mechanism of uranium adsorption by soil was discussed by fitting the experimental data. The main conclusions are as follows: (1) the pH of soil samples in the study area is 4.63, which is acidic, the moisture content is 1.39 and the water content is on the high side. The content of organic matter is 46.98 g / kg; the cation exchange capacity (CEC) is 46.98 cmol / kg; the total uranium content is 3.21 渭 g / g, belonging to uranium-contaminated soil. The static adsorption experiments show that: initial pH, initial uranium concentration, adsorption time, organic matter, phosphate, The influence of soil particle size on the adsorption of uranium is extremely significant, and the inhibition of adsorption of uranium by Cu ~ (2 +) CD ~ (2 +) Pb ~ (2 +) Zn in heavy metal ions has little effect on the adsorption of uranium by soil, while temperature has no significant effect on the ability of soil to adsorb uranium at room temperature. Under the conditions of adsorption temperature of 25 鈩，

本文編號：1855431