本文關鍵詞： 葡萄糖 水熱碳化 催化劑 吸附 鈾　出處：《西南科技大學》2017年碩士論文　論文類型：學位論文

【摘要】：鈾礦冶、核燃料前段及乏燃料后處理廢水中含有大量的鈾,對其進行處理及回收廢水中的鈾是對有限的鈾資源的充分利用,也將有效避免放射性廢水對人類的危害及對生態(tài)環(huán)境的破壞。吸附法以經濟、高效、操作簡單等優(yōu)點已經成為處理低濃度含鈾廢水及提取鈾的優(yōu)選方法。針對含鈾廢水的特殊性,研究開發(fā)具有抗輻射性及耐酸性能,且吸附容量大的新型吸附劑是吸附法處理放射性廢水的重中之重。本研究以葡萄糖為主要原料,通過水熱碳化、焙燒、KOH活化和酸化處理等方法制備了水熱碳微球及多孔氧化碳吸附劑,系統(tǒng)研究了低溫水熱碳化工藝及催化劑Al Cl3對碳微球形貌及性能的影響,以及碳微球的形成機理;研究了KOH用量和酸處理方法對多孔碳形貌及性能的影響。同時,研究了水熱碳微球及多孔氧化碳吸附劑對溶液中U(VI)的吸附特性和機理,探究了碳材料循環(huán)利用特性。結果表明:1、以葡萄糖為原料,Al Cl3為催化劑,采用水熱碳化法在120~150℃溫度范圍合成制備了水熱碳微球(HTC)。當Al Cl3用量為20 mol%、水熱碳化溫度為130℃,以及反應時間為20 h時,水熱碳微球呈單一球形且光滑表面。微球的粒徑分布為0.5~5.5μm,且表面擁有豐富的活性氧基團;碳微球內部存在有呋喃環(huán)結構,其在整個碳微球結構中所占的比例隨溫度升高而下降;經過焙燒的水熱碳微球(HTC-COOH),表面的羧基官能團增加,吸附位點增加,有利于碳微球對U(VI)的吸附。2、焙燒后的碳微球(HTC-COOH)對U(VI)的最佳吸附條件是:環(huán)境溫度為25℃、溶液p H值為4.5、初始濃度為140 mg·L-1、且吸附時間為22h。在此條件下,HTC-COOH碳微球對溶液中U(VI)的最大吸附量為163mg·g-1,吸附過程符合Langmuir等溫吸附模型及準二級動力學模型。HTC-COOH碳微球對U(VI)的吸附主要發(fā)生在其外表面,且主要是碳微球上的羧基與U(VI)之間發(fā)生離子交換,其次還有羥基與U(VI)之間的相互作用。3、以葡萄糖和尿素為原料先合成葡萄糖-尿素樹脂,再經管式氣氛爐焙燒、KOH活化和酸處理,制備了多孔氧化碳(m-a-4-NC)。研究了m-a-4-NC對溶液中U(VI)的吸附特性,當溶液p H值為4.5,吸附時間為120 min時,m-a-4-NC對U(VI)的最大吸附量為397 mg·g-1;吸附過程符合準二級動力學模型和Langmuir等溫吸附模型。多孔氧化碳材料對U(VI)的吸附主要為羧基與U(VI)之間的離子交換。4、采用FTIR、XPS、SEM及N2吸附-脫附等溫線模型等對多孔氧化碳材料的微觀形貌、化學結構及性能特性進行了表征。未經酸化處理的多孔碳(a-4-NC)含有豐富的開孔結構,經過酸化處理之后的m-a-4-NC材料的表面變得粗糙,但是材料內部的大孔及介孔結構依然存在,這有利于吸附U(VI)時液體的快速流動。
[Abstract]:There is a large amount of uranium in the waste water of uranium mining, nuclear fuel front and spent fuel reprocessing, and the treatment and recovery of uranium from waste water is the full utilization of limited uranium resources. It will also effectively avoid the harm of radioactive wastewater to human beings and ecological environment. The adsorption method is economical and efficient. The advantages of simple operation have become the optimal method for the treatment of low concentration wastewater containing uranium and the extraction of uranium. In view of the particularity of the wastewater containing uranium radiation resistance and acid resistance have been studied and developed. The new adsorbent with large adsorption capacity is the most important in the treatment of radioactive wastewater by adsorption. In this study, glucose was used as the main raw material and calcined by hydrothermal carbonization. Hydrothermal carbon microspheres and porous carbon oxide adsorbents were prepared by KOH activation and acidification. The effects of hydrothermal carbonization at low temperature and Al Cl3 catalyst on the morphology and properties of carbon microspheres were systematically studied. And the formation mechanism of carbon microspheres; The effects of KOH content and acid treatment method on the morphology and properties of porous carbon were studied. Meanwhile, the adsorption characteristics and mechanism of hydrothermal carbon microspheres and porous carbon oxide adsorbents for Utv I in solution were studied. The recycling characteristics of carbon materials were investigated. The results showed that: 1, with glucose as raw material, Al Cl3 was used as catalyst. Hydrothermal carbon microspheres (HTC) were synthesized by hydrothermal carbonization at a temperature range of 120,150 鈩，

本文編號：1446897