本文選題：矸石基NaX型沸石 + 重金屬��； 參考：《陜西師范大學(xué)》2015年碩士論文

【摘要】：煤矸石是煤炭開采、洗選過程排放的固體廢物,其大量堆積會(huì)對(duì)生態(tài)環(huán)境產(chǎn)生危害,因Al2O3和SiO2為其主要化學(xué)成分,可作為合成沸石分子篩原料。本文以陜西省白水煤礦的煤矸石為原料,制備出表面形貌完整的NaX型沸石分子篩。將所制備的NaX型沸石用作吸附劑,探討了其對(duì)Cd2+、Cr3+Cu2+三種重金屬離子在單元系統(tǒng)、雙元系統(tǒng)、三元系統(tǒng)中的吸附過程。因六價(jià)鉻的毒性比三價(jià)鉻大很多,所以本文探討了矸石基沸石及其改性沸石對(duì)Cr(Ⅵ)的吸附性能。共研究了三種不同試劑對(duì)矸石基NaX型沸石的改性方法及改性后沸石的吸附條件和機(jī)制,并用掃描電鏡對(duì)沸石改性前后的形貌進(jìn)行了表征。每個(gè)吸附過程都與等溫吸附模型和吸附動(dòng)力學(xué)模型進(jìn)行擬合。通過上述研究工作得出結(jié)論如下：(1)煤矸石經(jīng)破碎-粉磨-酸浸-洗滌-干燥-堿熔-陳化-晶化等過程合成出了表面形貌完整的NaX型沸石分子篩。其中堿熔配比為煤矸石：NaOH=1:1.2,堿熔溫度為650℃陳化時(shí)間為6 h,晶化溫度為110℃,時(shí)間為12 h。(2)矸石基NaX型沸石對(duì)Cd2+、Cu2+和Cr3+的吸附單因素影響實(shí)驗(yàn)中,最佳初始pH值為4,沸石添加量為0.15 g,隨著初始濃度的增加,沸石對(duì)三種重金屬離子的單位吸附量均有不同程度的增加,而去除率則逐漸減少。沸石對(duì)Cr3+的吸附無論在單元系統(tǒng)還是多元系統(tǒng),都60 min后達(dá)到吸附平衡。而沸石對(duì)Cd2+和Cu2+的吸附在單元系統(tǒng)和無Cr3+參加的系統(tǒng)中都能在5～10分鐘后達(dá)到吸附平衡,有Cr3+參加的系統(tǒng)中則是60 min后達(dá)到吸附平衡。(3)表征結(jié)果顯示,經(jīng)氯化鋁和十六烷基三甲基溴化銨(HDTMA)改性的矸石基沸石的晶型并沒有發(fā)生大的變化,改性后沸石的體積都比改性前略有擴(kuò)大,且表面都附著了改性劑。經(jīng)硫酸亞鐵改性的矸石基沸石其晶型被破壞。(4)改性前矸石基NaX型沸石對(duì)Cr(Ⅵ)的吸附效果在pH為8時(shí)最佳,但吸附率并不高。(5)不同改性劑的最佳改性條件分別為：硫酸亞鐵改性沸石的最佳改性濃度為0.3 mol/L,改性時(shí)間為2h；氯化鋁改性沸石的最佳改性濃度為20%,最佳改性時(shí)間為4 h；十六烷基三甲基溴化銨(HDTMA)改性沸石的最佳改性濃度為0.5%,最佳改性時(shí)間為2 h。(6)通過探討不同改性沸石吸附過程的影響因素,得到：三種改性沸石中,硫酸亞鐵改性沸石的最佳吸附初始pH值為4,氯化鋁改性沸石和十六烷基三甲基溴化銨(HDTMA)改性沸石的最佳吸附初始pH值為2。三種改性沸石對(duì)Cr(Ⅵ)的去除率隨初始濃度的升高而降低；其單位吸附量則隨初始濃度升高而增加。同等初始濃度和體積下,在實(shí)際應(yīng)用中改性沸石的用量需大于0.25 g方能達(dá)到無害效果。經(jīng)實(shí)驗(yàn)驗(yàn)證,三種改性沸石均能在120 min達(dá)到吸附平衡。(7)通過模型擬合發(fā)現(xiàn),所有的單元系統(tǒng)吸附過程都符合Langmuir等溫吸附模型和偽二級(jí)動(dòng)力學(xué)吸附模型,多元系統(tǒng)中矸石基NaX型沸石對(duì)三種重金屬離子的等溫吸附更符合擴(kuò)展的Langmuir模型。(8)通過比較不同的吸附劑在各自最佳pH值以及相同的其他吸附條件下對(duì)Cr(Ⅵ)的吸附效果得出,經(jīng)不同方法改性后,矸石基NaX型沸石對(duì)Cr(Ⅵ)的吸附效果均有不同程度提高,其中有機(jī)改性沸石的去除效果最好。
[Abstract]:Coal gangue is a solid waste discharged from coal mining and washing process. A lot of accumulation will be harmful to the ecological environment. Because Al2O3 and SiO2 are the main chemical components, it can be used as the raw material of synthetic zeolite molecular sieves. In this paper, the NaX zeolite molecular sieves with complete surface morphology are prepared from the coal gangue of Shaanxi Baishui coal mine. NaX zeolite is used as an adsorbent. The adsorption process of three heavy metal ions of Cd2+ and Cr3+Cu2+ in unit system, dual system and three element system is discussed. The toxicity of six valence chromium is much larger than that of trivalent chromium. Therefore, the adsorption properties of gangue based zeolite and its modified zeolite to Cr (VI) are discussed in this paper. A total of three different reagents have been studied. The modified method of stone based NaX zeolite and the adsorption conditions and mechanism of the modified zeolite were characterized by scanning electron microscope. Each adsorption process was fitted with the isothermal adsorption model and adsorption kinetic model. Through the above research work, the conclusion was drawn as follows: (1) the coal gangue was broken through grinding and acid leaching. NaX zeolite molecular sieves with complete surface morphology were synthesized by washing - drying - alkali melting - aging and crystallization. The ratio of alkali fusion was NaOH=1:1.2, alkali melting temperature was 6 h at 650 C, crystallization temperature was 110, and 12 h. (2) NaX zeolite of Gangue Based on Cd2+, Cu2+ and Cr3+ The initial pH value is 4 and the zeolite addition is 0.15 g. With the increase of initial concentration, the unit adsorption capacity of the three heavy metal ions is increased in varying degrees, while the removal rate decreases gradually. The adsorption equilibrium of zeolite to Cr3+ is reached after 60 min in the unit system or in the multiple system. The adsorption of zeolite to Cd2+ and Cu2+ is the absorption of zeolite. The adsorption equilibrium can be reached in the unit system and the system without Cr3+ participation in 5~10 minutes. The adsorption equilibrium is reached after 60 min in the system with the participation of Cr3+. (3) the characterization results show that the crystalline form of the Gangue Base boiling stone modified by aluminum chloride and sixteen alkyl three methyl ammonium bromide (HDTMA) has not changed greatly, and the modified zeolite has been modified. The volume of the Modified Gangue based zeolite modified by ferrous sulfate was destroyed. (4) the adsorption of Cr (VI) on the Modified Gangue Based NaX zeolite was best at the time of pH 8, but the adsorption rate was not high. (5) the optimum modification conditions of different modifiers were the modified boiling of ferrous sulfate. The best modified concentration of the stone was 0.3 mol/L and the modified time was 2h, the optimum modified concentration of aluminum chloride modified zeolite was 20%, the optimum modification time was 4 h, the optimum modified concentration of sixteen alkyl three methyl ammonium bromide (HDTMA) modified zeolite was 0.5%, the optimum modification time was 2 h. (6), and the influence factors of the adsorption process of different modified zeolite were discussed. The optimum adsorption initial pH value of the three modified zeolite was 4, the optimum adsorption initial pH value of aluminum chloride modified zeolite and sixteen alkyl three methyl ammonium bromide (HDTMA) modified zeolite was 2. three kinds of modified zeolite, and the removal rate of Cr (VI) decreased with the increase of initial concentration; and its unit adsorption amount followed the initial concentration. In the same initial concentration and volume, the dosage of modified zeolite needed to be more than 0.25 g can achieve harmless effect under the same initial concentration and volume. The three modified zeolites can achieve the adsorption equilibrium at 120 min. (7) the adsorption process of all the unit series is in accordance with the Langmuir isothermal adsorption model and the model fitting. The pseudo two stage kinetic adsorption model, the isothermal adsorption of three heavy metal ions by the Gangue Based NaX zeolite in the multicomponent system is more consistent with the extended Langmuir model. (8) by comparing the adsorption effects of different adsorbents on the Cr (VI) under the best pH values and the same other adsorption conditions, after the modification of different methods, the gangue base NaX The adsorption effect of zeolite on Cr (VI) has been improved to varying degrees, among which organic modified zeolite has the best removal effect.

【學(xué)位授予單位】：陜西師范大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：X703;X752

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本文編號(hào)：1839597