【作者】 黄昭先；

【导师】 王兴国；

【作者基本信息】 江南大学 ， 粮食、油脂及植物蛋白工程， 2012， 硕士

【摘要】 我国凹凸棒土矿产资源丰富,凹凸棒土作为工业应用广泛的非金属矿,具有良好的吸附功能。近年来,抗生素污染已渐渐成为人们关注的焦点。本文以凹凸棒土为吸附剂,探索其在治理抗生素方面的应用。首先,采用不同方法对凹凸棒土进行改性,结果发现,改性凹凸棒土对四环素的吸附性能大小分别为酸活化土、原土、煅烧土、KH550改性土、十八烷基三甲基氯化铵改性土;对盐酸活化工艺进行优化,得到最优条件:盐酸浓度0.5 mol/L、温度40 oC、固液比为1:8、活化时间1 h。其次,研究四环素在凹凸棒土上的吸附过程,结果发现,四环素在凹凸棒土上的吸附更加符合准二级动力学方程模型;初始阶段,四环素在凹凸棒土上的吸附速率是由表面扩散控制的;凹凸棒土对四环素的吸附是一个自发的吸热过程,符合Freundlich方程模型;四环素在凹凸棒土上的解吸附过程具有滞后性。再次,研究pH和离子浓度对凹凸棒土吸附四环素的影响,试验结果表明,四环素的单位吸附量随着体系pH的提高而增加,在pH为3.0时达到最大,然后随着pH的增大而降低;四环素的单位吸附量随着体系中离子浓度的增加而减少,并且各种离子的影响效果为Mg²⁺ > Ca²⁺>K⁺>Na⁺。对已吸附的凹凸棒土进行再生,实验结果表明,采用在加热条件下采用稀碱对凹凸棒土吸附剂进行处理具有良好的再生效果;稀碱再生的优化条件为在NaOH浓度为0.004 mol/L,温度为60 oC,反应时间分别为60 min,再生率为93.5%;采用稀碱处理对凹凸棒土吸附剂进行再生处理具有良好的重复性。对试验得到的凹凸棒土样品进行性能表征,研究其结构变化。实验结果表明,红外光谱、热重分析和XRD的分析表明盐酸处理过程并未根本改变凹凸棒土晶体结构;凹凸棒土经过酸活化后的比表面积和平均孔径略有提高,再生凹土的比表面积明显降低,平均孔径有所下降,吸附饱和土的比表面积急剧降低,平均孔径出现一定程度的下降。最后,我们推测,初始阶段,四环素在凹凸棒土上的吸附是表面吸附的过程,体系中电荷情况影响凹凸棒土的吸附性能。更多还原

【Abstract】 China has a lot of attapulgite mineral resources, as an industrial widely applied non-metallic mine, attapulgite is good of sorption ability. Recent years, people have been focusing on antibiotic pollution seriously. This paper takes attapulgite as adsorbent, studies the sorption of antibiotic on attapulgite.Used different methods to modify attapulgite, it was found from the result: Sorption ability of modified attapulgites is hydrochloric acid modified attapulgite > raw attapulgite > high-fired attapulgite > KH550 modified attapulgite > Octodecyl trimethyl ammonium chloride modified attapulgite; On this basis, optimized hydrochloric acid modification, the optimum conditions are hydrochloric acid concentration 0.5 mol/L, temperature 40 oC, solid-to-liquid ratio 1:8, reaction time 1 hour.The result from the study of the mechanism of sorption of tetracycline on attapulgite was: the experimental kinetic data were appropriate to fit the pseudo-second-order kinetics model; the sorption rate of tetracycline on attapulgite was determinated by surface diffusion; the sorption of tetracycline was a spontaneous endothermic process, Freundlich isotherm was more appropriate method to determine the present system; there is a hysteresis in desorption process.Changed the pH and ionic concentration of tetracycline solution to research their effect on sorption of tetracycline on attapulgite, it was drawed from the result that the sorbed tetracycline amount increased as the pH increased, and raise to maximum when pH was 3.0, after that, decrease as the pH increased; the sorbed tetracycline amount decrease as the ionic concentration increased, the ionic effect is Mg2+ > Ca2+>K+>Na+.Regenerated the used attapulgite adsorbent with different methods, the result could be found that taking thin alkali to regenerate attapulgite adsorbent under heating condition was a effective way; On this basis, optimized regeneration, the optimum conditions are sodium hydroxide concentration 0.004 mol/L, temperature 60 oC, reaction time 1 hour, regeneration rate 93.5%; with thin alkali theated, attapulgite adsorbent regenaretion had a good repeatability. Analysed the change of the attapulgite structure, the result showed that: FTIR, thermogravimetric analysis and XRD indicated hydrochloric acid modification did not change attapulgite structure radically; the specific surface area and average pore diameter of hydrochloric acid modified attapulgite enlarged slightly, regenerated attapulgite’s specific surface area declined obviously, its average pore diameter reduced a little, the saturated sorbed attapulgite’s specific surface area reduced sharply, its average pore diameter had a certain reduction. At last, we determined that the sorption of tetracycline on attapulgite is a surface sorption process.更多还原