【作者】 张雪梅；

【导师】 张岩；

【作者基本信息】 大连理工大学 ， 能源与环境工程， 2014， 硕士

【摘要】 腐殖质(Humic substances,HS)是天然水体中有机质的主要组成成分。腐殖酸(Humic acids, HAs)和单宁酸(Tannic acids, TAs)是HS中两种具有不同分子量分布的高分子化合物。水源中HAs和TAs的存在不但引起了水的颜色、气味和味道等问题,而且在饮用水加氯消毒过程中还会形成三卤甲烷类等具有诱变属性的有害消毒副产品。因此,去除天然水源中的HAs和TAs是人类当前面临的重大课题。本论文采用静态吸附实验与吸附材料的物性及结构表征相结的方法,研究了活性炭和粉煤灰对腐殖酸和单宁酸的脱除性能、脱除机理、影响因素及相关指标间的关系。首先,分析了活性炭的孔结构参数与其吸附性能指标间的关系。经分析发现,活性炭的比表面积、碘吸附值、亚甲蓝吸附值与其微孔容积具有很好的相关性。其次,研究了活性炭的特性参数与其对TAs和HAs的脱除能力之间的关系,并分析了活性炭脱除HAs过程的影响因素。研究发现：(1)碘吸附值和亚甲蓝吸附值不能正确预测出活性炭对TAs和HAs的脱除能力；(2)焦糖脱色率指标可以有效地预测出活性炭对TAs的脱除能力,但不能正确预测出活性炭对HAs的脱除能力；最后,分析了粉煤灰对TAs和HAs的脱除机理以及富钙煤灰脱除HAs过程的影响因素。结果表明：(1)粉煤灰对TAs的脱除机理与活性炭对TAs的脱除机理相同,主要依靠物理吸附作用；(2)富钙煤灰对HAs的脱除效果显著优于孔结构发达的商业活性炭,原因在于富钙煤灰与活性炭对HAs的脱除机理不同,富钙煤灰对HAs的脱除主要依靠钙基矿物质释放出的Ca2+对腐殖酸的凝聚作用,而活性炭对HAs的脱除则主要依靠孔隙的物理吸附作用；(3)富钙煤灰对HAs的脱除率会受煤灰投加量、溶液初始pH值和温度等因素的影响,因为这些因素都会影响到溶液中Ca2+的浓度。本论文的研究结果表明,富钙煤灰可以作为含腐殖酸类有机物废水的廉价、高效处理剂。更多还原

【Abstract】 Humic substances (HS) is the main component of the organic matter in natural waters. Humic acids (HAs) and Tannic acids (TAs) are two kinds of polymer compounds with different molecular weight distribution in the HS. The existence of HAs and TAs in water resources is troublesome not only for causing color, odor, and taste problems but also for forming trihalomethanes and other harmful disinfection byproducts that exhibit mutagenic properties during the chlorination step in drinking water treatment. Therefore, the removal of HAs and TAs from natural water sources is a major issue faced by people currently.In this thesis, the removal performance of HAs and TAs from aqueous solution was studied under the static adsorption conditions using commercial activated carbons (ACs) and fly ashes (FAs) as testing materials.The effect of temperature, initial pH, coal ash dose on HA removal was discussed. The HA removal mechanisms by ACs and FAs were proposed in conjunction with a sets of chemical and structural characterization techniques.Firstly, the correlation between porous structure parameters and adsorption performance indicators of ACs was analyzed. It is found that the adsorption capacities of iodine and methylene blue on ACs were closely correlated with the microporous volums and specific surface areas of ACs.Secondly, the static adsorption tests were conducted to investigate dependence between porous structure parameters of ACs and removal efficiency (Re) of HAs and TAs from aqueous solutions. The results show that:(1) iodine and methylene blue adsorption capacities are unable to reflect the Re of TAs and HAs by ACs; and (2) caramel indicator can be used as a valid prediction for the removal capacity of TAs by ACs, however, it fails to predict the removal capacity of HAsfrom aqueous solution by ACs.Finally, a series of batch experiments were conducted to study the removal mechanism of HAs and TAs by FAs. The influences of ash dosage, initial pH and temperature on the removal of HAs by calcium-rich FA were also analyzed. The following conclusions can be deduced:(1) The removal process of TAs on ACs and FAs is mainly a physical adsorption process;(2) Physical adsorption is the major process in the AC-HAs system while aggregation predominately occurs in the calcium-enriched FA-HAs system due to the contribution of Ca2+cations;(3) The removal performance of HAs by calcium-enriched FA is strongly dependent on temperature, initial pH, and dosage of FA. All these factors are considered to be associated with the concentration of Ca+cations in solution.The results obtained in this study suggested that calcium-enriched FA could be useful and cost-effective in the treatment of wastewaters containing HAs-like organic macro-molecules instead of commercial ACs.更多还原