【作者】 连会；

【导师】 彭奇均；

【作者基本信息】 江南大学 ， 化学工艺， 2007， 硕士

【摘要】 蜂蜜是一种天然营养佳品,其主要成分是糖,其中还原糖占总成分含量的65%以上。在储存时间过长或加热温度过高,还原糖易转化为羟甲基糠醛,影响到蜂蜜的口感和外观。同时,养蜂业中,为防治蜂病,给蜜蜂喂养四环素类抗生素造成蜂蜜中四环素的残留。本文考察吸附剂——颗粒活性炭对四环素和羟甲基糠醛的吸附能力,为吸附法去除蜂蜜中这两种物质提供一定的依据。首先,对四环素和羟甲基糠醛含量测定方法进行了研究。采用双波长紫外分光光度法测定蜂蜜中的四环素和羟甲基糠醛含量,具有较好的准确度和精确度,相对标准偏差在0.5%-7%之间,回收率均为84%以上。此法用于测定四环素和羟甲基糠醛模拟混合液中各组分含量,则具有快速,简便优点。化学显色法测定蜂蜜中羟甲基糠醛,干扰少,重复性好,准确度高,相对标准偏差小于2.5%,回收率94%-101%。考察颗粒活性炭物理参数与其对四环素和羟甲基糠醛吸附性能的关系。研究表明,活性炭颗粒度变小有助于吸附能力的提高,活性炭比表面积、碘吸附值及亚甲基蓝吸附值与其对四环素和羟甲基糠醛吸附容量呈一定的线性关系。通过静态吸附法研究了LH-15颗粒活性炭吸附四环素和羟甲基糠醛的动力学及热力学。动力学研究表明:溶液pH、起始浓度及温度对过程中吸附率/吸附容量、吸附速率有一定的影响。最适pH为4。LH-15颗粒活性炭吸附四环素的动力学模型符合准二级动力学模式,且随着起始浓度的增加,k₂值下降;吸附HMF时,符合准一级动力学模式,k₁值随着浓度增加有所增加。由此表明,液膜扩散是LH-15型GAC吸附四环素和羟甲基糠醛过程的控制步骤。热力学研究表明:LH-15颗粒活性炭对TC和HMF的吸附等温线均较符合Langmuir模式,温度升高,q₀均增大,相应的等温常数b下降。从吸附热力学性质判断,LH-15颗粒活性炭吸附TC和HMF的过程为放热反应。同时,吸附焓的绝对值小于40 kJ/mol。表明吸附过程为物理吸附。最后利用硝酸对LH-15型颗粒活性炭进行表面液相氧化改性。考察了改性因素（硝酸浓度、温度、时间）对活性炭表面酸性基团、孔隙结构等物化参数的影响。同时也考察了活性炭物化参数变化对其吸附四环素和羟甲基糠醛性能的影响。通过正交试验极差分析,温度、硝酸浓度是影响活性炭物化参数的主要因素;改性温度也是影响改性活性炭吸附四环素和羟甲基糠醛的主要因素,浓度、时间对吸附羟甲基糠醛的影响较小。对四环素和羟甲基糠醛吸附性能较好的改性条件为:硝酸浓度25%,温度30℃,时间6h。同时,改性活性炭对四环素的吸附性能是物理吸附与化学吸附共同作用的结果,对羟甲基糠醛的吸附主要以物理吸附为主。更多还原

【Abstract】 Honey, which was the nature nutriment, consisted of over 65% reduce sugar. Stored overtime or treated overheat, reduce sugar converted to hydroxymethylfurfural(HMF) easily, which would influence the taste and appearance of honey. Meanwhile, beekeeper often fed antibiotics such as tetracycline(TC) to bees, which would bring rudimental antibiotics in honey. So the adsorption method was studied to remove the HMF and TC using granule active carbon(GAC).Firstly, the methods of determining the contents of HMF and TC were studied. The bi-wavelengh ultraviolet method possessed high accuracy and recoveries were 84% above. It was applicable to simulation solution. In order to avoid the disturbance, derivative spectrophotometric method was fit to determine HMF, recoveries were over 94%.The studies demonstrated relative face area, iodine value and methylene blue value had the liner relationship with the adsorption capacity of GAC to HMF and TC.The mechanisms for LH-15 GAC to adsorb HMF and TC from honey in the adsorption kinetics and thermodynamics view were studied. Kinetics study demonstrated that the optimum pH was 4 to obtain the biggest adsorption velocity. The adsorption processes were accord with the pseudo second-order equation for TC and the pseudo first-order equation for HMF. The key dominate steps were liquid diffusion. The thermodynamics results showed that the equilibrium adsorption isotherms were accord with Langmuir model. The processes belonged to the physics adsorption.The surface chemical properties of GAC modified by nitric acid had significant influence on its adsorption performance. The purpose of studies lied in making clear the effect of modification factors, physical and chemical properties, which would influence the adsorption capacity. The results showed that the modification temperature was the main factor influencing the adsorption performance. The best conditions were obtained: nitric acid concentration was 25%, modification temperature was 30℃, modification time length was 6h. Meanwhile, the results demonstrated that the process was the effects the physical adsorption and chemical adsorption to adsorb TC on modification GAC, and the main effect was physical adsorption to HMF更多还原