【作者】 陈浩；

【导师】 廖利； 廖筱锋；

【作者基本信息】 华中科技大学 ， 环境工程， 2020， 硕士

【摘要】 随着城市工业化的快速发展,我国的污水处理效率日渐提升,但另一方面处理污水后排出的污泥量也不断增加。目前国内采用的污泥处置方案相对落后,将其任意堆放或采取简单填埋等方式,严重影响了周边环境,造成“污泥围城”的局面。本研究以市政污泥为原材料,在此基础上加入碳酸钾作为活化剂、玉米秸秆作为增碳剂,通过化学活化法制备出污泥基活性炭。取原料干基比（污泥:秸秆:碳酸钾）、炭化温度和炭化时间三种影响因素进行正交实验,基于碘吸附值、比表面积以及活性炭产率三种数据判断极差和方差,从而确定最佳工艺条件为:原料干基比3∶7∶0.25,炭化温度800°C,炭化时间2.0 h。表征分析结果表明,污泥秸秆基活性炭平均产率是51.10%,平均碘吸附值为641.91 mg/g,平均比表面积为815.353 m²/g。孔径分析表明其孔隙结构发达,总孔体积是0.443cm³/g,而微孔体积则是0.2660 cm³/g,平均孔径3.002 nm,由此可证属于微孔活性炭。热重/差热分析表明活化剂K₂CO₃能够降低物料的活化能,促进热解反应更易发生。傅里叶红外光谱仪（FT-IR）分析结果表明其表面含有丰富的官能团,包括O-H、C-H、–CH₂–和C=C等,碳酸钾的存在对污泥活性炭的表面性质有一定的影响。氮气吸脱附等温线分析表明,该吸脱附等温线属于I型和IV型等温线的结合体。利用最佳活性炭对浓缩液的静态吸附表明,其对浓缩液具有很好的吸附能力。取60 m L浓缩液,当活性炭的投加量为1 g,吸附时间达到100 min,浓缩液p H为9,吸附温度在30°C状态下,活性炭对COD的去除率效果最理想。处于理想状态下,吸附后浓缩液的COD浓度为276 mg/L,去除率达到78.43%,活性炭吸附量为60.24 mg/g。拟合其吸附等温线方程,结果表明吸附过程中多层吸附的贡献率相对高一些,Freundlich模型拟合度较好,相关系数较大。更多还原

【Abstract】 With the rapid development of urban industrialization,the efficiency of sewage treatment in China is gradually increasing,but on the other hand,the amount of sludge discharged after the treatment of sewage is also increasing.At present,the sludge disposal scheme adopted in China is relatively backward.Stacking it arbitrarily or adopting simple landfill methods have seriously affected the surrounding environment and caused the situation of“sludge besieged the city”.This study used municipal sludge as raw materiall,and then added potassium carbonate as an activator,corn stalk as a carbon enhancer,and prepared a sludge-based activated carbon by chemical activation.It took the dry basis ratio of raw materials（sludge:straw:potassium carbonate）,carbonization temperature and carbonization time to perform orthogonal test,based on iodine adsorption value,specific surface area and activated carbon output data to determine the range and variance.In order to determine the best process conditions:the raw material dry basis ratio is 3:7:0.25,the carbonization temperature is 800°C,and the carbonization time is 2.0 h.Characterization analysis results showed that the average yield of sludge straw-based activated carbon was 51.10%,the average iodine adsorption value was641.91 mg/g,and the average specific surface area was 815.353 m²/g.The pore size analysis showed that the pore structure was well developed,the total pore volume was0.443 cm³/g,and the micropore volume was 0.2660 cm³/g,and the average pore diameter was 3.002 nm,which could be proved to be microporous activated carbon.Thermogravimetric/differential thermal analysis showed that the activator K₂CO₃could reduce the activation energy of the material and promoted the pyrolysis reaction to occur more easily.FT-IR analysis results showed that the surface was rich in functional groups,including O-H,C-H,–CH₂–and C=C.The presence of potassium carbonate had a certain effect on the surface properties of sludge activated carbon.Nitrogen adsorption and desorption isotherm analysis showed that the adsorption and desorption isotherm belonged to the combination of type I and type IV isotherms.The static adsorption of the concentrated liquid using the best activated carbon showed that it had a good adsorption capacity for the concentrated liquid.Taking 60m L of concentrated liquid,when the dosage of activated carbon was 1 g,the adsorption time reached 100 min,the p H of the solution is 9,and the adsorption temperature was narrow at 30°C,the effect of activated carbon on the removal rate of COD was optimal.In an ideal state,the COD concentration after adsorption was 276mg/L,the removal rate reached 78.43%,and the activated carbon adsorption amount was 60.24 mg/g.Fitting the adsorption isotherm equation,the results showed that the contribution rate of multi-layer adsorption was relatively higher during the adsorption process,the Freundlich model had a better fit and a larger correlation coefficient.更多还原