【作者】 何莹；

【导师】 廖利；

【作者基本信息】 华中科技大学 ， 环境工程， 2015， 硕士

【摘要】 活性炭是一种孔隙结构发达、表面化学性质丰富的固体吸附材料,在H2S脱除中有重要应用。市政污泥和农作物秸秆是城市生活和农业生产的两大废弃物,将这两种废弃物用于制备具有工业应用价值的活性炭材料,对其资源化利用和环境污染治理具有重要意义。本文以市政污泥和玉米秸秆为原料,通过KOH活化法制备污泥-秸秆基活性炭,并将其用于H2S的吸附脱除,系统研究了活性炭的活化反应过程并对脱硫机理进行了初步探讨。主要研究内容及结论如下:(1)当料碱比一定时,随着原料中秸秆比例的增加,活性炭得率逐渐减少,比表面积、总孔容、微孔容、微孔率均逐渐增大,H2S的穿透时间和饱和时间逐渐延长,对应的硫容逐渐增大。污泥和秸秆的适宜干基质量比为3:7。(2)活性炭的孔隙结构以中孔为主,微孔含量较少。适量的KOH有利于活性炭孔隙结构的发展,而过量的KOH则会使部分微孔扩大为中孔甚至大孔。料碱比为10:2的活性炭(C372)微孔率最高,脱硫效果最好。(3)对KOH活化过程和机理的研究发现,KOH有利于易分解有机物的提前分解,适量的KOH还可以促进难分解物质的热解。活化产物主要是K2CO3。(4)活性炭的脱硫活性与微孔率的增大规律一致,C372和C374型活性炭的微孔率最大,分别为0.590和0.587,对应的饱和硫容也最大,分别为7.00和6.59mg H2S/g脱硫剂。因此,活性炭的硫容是由微孔容和总孔容协同决定的。(5)活性炭脱硫的主要产物是单质硫和少量硫酸,推断活性炭失活的主要原因是脱硫产物将微孔全部充满或孔口全部堵塞。更多还原

【Abstract】 Activated carbon is a solid adsorbent material with well-developed pore structure and unique surface chemistry and has been widely used for H2 S removal. Municipal sludge and crop straw are two kinds of waste from urban life and agricultural production, preparing activated carbon material which has industrial application value with them is of great significance to the resource utilization and environmental pollution control. In this paper, municipal sludge and corn stalk were used to prepare sludge-stalk based activated carbon by pyrolysis with KOH. The adsorbent prepared was applied to the H2 S removal, the activating reaction process of activated carbon was systematically studied and the desulfurization mechanism was preliminarily discussed. The main contents and conclusions are as follows:(1) When the mixture/KOH ratio was certain, with the increase of the stalk proportion in feedstock, the yield of activated carbon was decreased, the specific surface area, total pore volume, micropore volume and Vmicro/Vtotal rate were increased, the breakthrough and saturation time of H2 S were extended, and the corresponding sulfur capacities were increased. The suitable quality ratio(dry basis) of sludge and stalk was 3:7.(2) The pores in the activated carbons were mainly mesopores and the micropores were less. Moderate KOH was conducive to the pore development in activated carbon while excess KOH made part of the micropores expand to mesopores and even macropores. The activated carbon(C372) whose mixture/KOH ratio was 10:2 had the highest Vmicro/Vtotal rate and the best desulfurization efficiency.(3) From the research on KOH activation process and mechanism, it was discovered that adding suitable amount of KOH not only brought the decomposition of the easily degradable substance forward, but also promoted the pyrolysis of the hardly degradable substance. The activation product was mainly K2CO3.(4) The bigger the Vmicro/Vtotal rate of activated carbon, the higher the desulfurization activity. The Vmicro/Vtotal rates of C372 and C374 were maximum, 0.590 and 0.587 respectively, and the corresponding saturation sulfur capacity were also the largest, 7.00 and 6.59 mg H2S/g catalyst, respectively. Therefore, the sulfur capacity of activated carbon was determined by micropore volume and total pore volume synergistically.(5) The products of H2 S oxidation over the activated carbon were mainly elemental sulfur and a little sulfuric acid. The main reason for activated carbon inactivation was that all the micropores were filled with the desulfurization products or all the ostioles were blocked.更多还原