本文選題：黃土　切入點：石油污染物　出處：《蘭州交通大學(xué)》2015年碩士論文

【摘要】：添加外源性物質(zhì)(秸稈焚燒物和生物碳)可改良貧瘠黃土、提高肥力。研究外源性物質(zhì)對寒旱區(qū)黃土吸附石油污染物的影響,對石油污染物在黃土中的歸趨有重要意義。本文在研究寒旱區(qū)黃土對石油污染物的吸附特性的基礎(chǔ)上,采用熱重分析、元素分析、紅外光譜分析、比表面積分析和電鏡掃描表征小麥秸稈焚燒物(BC-ash)和生物碳(BC-200、BC-400、BC-600)的結(jié)構(gòu)特征,分析不同的外源性物質(zhì)對黃土吸附石油污染物的影響;初步探討了柴油污染黃土對多環(huán)芳烴的吸附性能,并定量描述了柴油污染黃土上分配作用和表面作用對吸附總量的貢獻。研究取得了以下成果:(1)熱重、紅外光譜分析結(jié)果顯示小麥秸稈在熱解溫度升高到350℃時失重率最大,為33.73%,秸稈的熱解過程發(fā)生化學(xué)鍵的斷裂及脂肪性烷基鏈的消失;小麥秸稈焚燒物的產(chǎn)率、灰分分別為12%、64.78%,灰分較大;生物碳隨著碳化溫度的升高,其產(chǎn)率降低,灰分含量增大;隨著熱解溫度升高,生物碳逐漸成為“富碳顆粒”,其極性降低,芳香性增大,疏水性增強;電鏡掃描分析顯示隨著碳化溫度升高,生物碳孔壁逐漸變薄,內(nèi)部孔結(jié)構(gòu)逐漸增大,甚至出現(xiàn)大量微孔。(2)寒旱區(qū)黃土對萘的吸附在10h內(nèi)為快速吸附過程,24h達到吸附平衡;Pseudosecond-order模型能較好地描述萘在黃土上的動力學(xué)吸附過程,吸附過程由外部液膜擴散、表面吸附、顆粒內(nèi)擴散控制;黃土對萘的吸附以分配作用為主,Henry和Freundlich模型均能很好地描述其吸附特性;黃土對萘的吸附是一個自發(fā)進行的吸熱過程,隨著溫度的升高,萘的飽和吸附量增大,熵變是主要驅(qū)動力;比較兩種黃土,蘭州(LZ)對萘的飽和吸附量高于嘉峪關(guān)(JYG),黃土中粉粒含量也能顯著影響吸附作用。(3)添加秸稈焚燒物黃土對萘的快速吸附過程在10h內(nèi)完成,24h達到吸附平衡;初始濃度的增大增加了黃土及秸稈焚燒物顆粒表面吸附位點與萘的碰撞頻率,導(dǎo)致平衡吸附量的增大;動力學(xué)吸附過程符合Pseudo-second-order模型,吸附的起始階段萘分子迅速占據(jù)黃土顆粒及秸稈焚燒物吸附位點,之后吸附劑通過微孔擴散機制進入其內(nèi)部;添加秸稈焚燒物黃土對萘的吸附是物理吸附,溫度升高,有利于吸附的進行;添加秸稈焚燒物黃土對萘的吸附量略低于黃土本身,表明土壤有機質(zhì)及其他組分與萘在吸附位點形成競爭吸附。(4)添加生物碳黃土對萘的吸附能力明顯提高,快速吸附過程在10h內(nèi)完成,吸附在20h達到平衡;動力學(xué)吸附過程符合Pseudo-second-order模型,吸附是多種機理控制的復(fù)雜體系多介質(zhì)反應(yīng);添加生物碳使黃土吸附萘的非線性增強,生物碳多孔結(jié)構(gòu)和芳香性影響吸附過程;生物碳熱解溫度越高,對黃土的非線性吸附過程影響越顯著;酸洗過程能很大程度上去除灰分,但對生物碳無定型活性組分改變較顯著,導(dǎo)致酸洗對不同溫度條件下制備的生物碳吸附性能的影響有差異;(4)柴油污染黃土對萘的吸附在72h內(nèi)達到平衡,柴油的存在顯著延長了黃土對萘的動力學(xué)吸附過程;低濃度柴油污染黃土對萘的吸附量比高濃度柴油污染黃土大,其機理為高濃度條件下柴油類污染物與萘形成競爭吸附降低了萘在柴油污染黃土上的平衡吸附量;萘在柴油污染黃土上的吸附為非線性吸附過程,該過程既包含物理吸附也包含化學(xué)吸附;外源性物質(zhì)的添加增大了表面吸附作用的貢獻率,但柴油污染黃土上的表面吸附和分配作用都明顯減弱;黃土中的柴油形成獨立吸附相,對整個吸附過程有影響。
[Abstract]:The addition of exogenous substances (straw burning and biological carbon) can improve barren loess, improve soil fertility. Effects of exogenous substances on the adsorption of petroleum pollutants in cold and arid regions of the loess, the oil pollutants in the Loess fate has important significance. Based on the characteristics of adsorption of the dye on the stone cold and arid region of loess on the oil, using thermogravimetric analysis, elemental analysis, infrared spectroscopy, surface area analysis and SEM analysis of wheat straw burning material (BC-ash) and biological carbon (BC-200, BC-400, BC-600) structure, analysis of the impact of exogenous substances of different adsorption of petroleum pollutants in loess; to explore the adsorption performance of diesel contaminated loess for PAHs, and the quantitative description of the distribution of loess diesel pollution effect and surface effect on the adsorption of the total contribution. The research has achieved the following results: (1) thermogravimetry, infrared spectroscopy analysis showed that Wheat straw increased to 350 degrees in the pyrolysis temperature is 33.73%, the maximum weight loss rate, fracture and fatty alkyl chain of straw pyrolysis process of the chemical bond disappeared; wheat straw burning material yield, ash content were 12%, 64.78%, high ash; biological carbon with increasing carbonization temperature, the yield decreased. The ash content increases; with increasing pyrolysis temperature, the biological carbon gradually become a "carbon rich particles", which decreased the polarity of aromaticity increases, and increase the hydrophobicity; scanning electron microscopy analysis showed that with the carbonization temperature, the biological carbon hole wall thinning, the internal pore structure increases gradually, and even the emergence of a large number of micropores (2) adsorption. Cold and arid regions on the Loess of naphthalene in 10h rapid adsorption process, 24h adsorption equilibrium; Pseudosecond-order model can better describe the dynamic adsorption process of naphthalene in the Loess on the adsorption process by external film diffusion, surface adsorption, Particle diffusion control; adsorption of naphthalene on Loess distribution function, Henry and Freundlich model can well describe the adsorption properties; adsorption of naphthalene in the loess is a spontaneous endothermic process, with the increase of temperature, the saturated adsorption capacity of naphthalene increases, the entropy change is the main driving force; two loess, Lanzhou (LZ) on the adsorption capacity of naphthalene is higher than that of Jiayuguan (JYG), can significantly affect the adsorption of silt content in loess. (3) add straw burning process of loess rapid adsorption of naphthalene on 10h, 24h reached adsorption equilibrium; the concentration of collision frequency increases the Loess and the burning of straw particles and surface adsorption sites of naphthalene, increase the equilibrium adsorption; dynamic adsorption process with the Pseudo-second-order model, the initial stage of naphthalene molecular adsorption material quickly occupy adsorption sites of loess grains and straw burning, After adsorption by micropore diffusion mechanism is added into the interior; physical adsorption, adsorption of naphthalene on Loess straw burning temperature was beneficial to adsorption; adding straw burning adsorption capacity of naphthalene compounds in loess is slightly lower than that of loess itself, soil organic matter and its components and he formed in the naphthalene adsorption sites of competitive adsorption. (4) add biological carbon on the Loess naphthalene adsorption capacity increased significantly, the rapid adsorption process within 10h, the adsorption reached equilibrium in 20h; dynamic adsorption process with the Pseudo-second-order model, the adsorption is a complex system of multiple control mechanism of multi medium reaction; the Loess nonlinear adsorption of naphthalene enhanced biological carbon addition, biological adsorption process carbon porous structure and aromatic effect; biological carbon pyrolysis temperature is higher, the nonlinear adsorption process of the Loess influence is more significant; the pickling process can remove ash largely, but Amorphous active components change significantly on the biological carbon, cause effect of pickling on under different temperature conditions for bio carbon adsorption by the difference; (4) the adsorption of diesel contaminated loess on naphthalene reached balance within 72h, the presence of diesel significantly extended the power of the naphthalene adsorption process of low concentration loess science; the adsorption capacity of high concentration pollution of diesel diesel pollution loess for naphthalene, the mechanism for the high concentration of diesel pollutants and reduce the formation of naphthalene competitive adsorption equilibrium adsorption of naphthalene in diesel contaminated loess on the amount of adsorption of naphthalene on diesel pollution; loess on the nonlinear adsorption process, this process includes not only physical adsorption is also included chemical adsorption; exogenous substances added to increase the surface adsorption contribution rate, but the surface adsorption and distribution effect of diesel pollution on the loess are significantly reduced; the Loess formed independent diesel adsorption Phase, it has an effect on the whole adsorption process.

【學(xué)位授予單位】：蘭州交通大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：X53

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相關(guān)期刊論文 前1條

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本文編號：1660150