【作者】 李红霞；

【导师】 何少华；

【作者基本信息】 南华大学 ， 市政工程， 2007， 硕士

【摘要】 通过实验研究了天然海泡石和热改性海泡石对水中阴离子染料酸性红57(AR57)和酸性蓝62(AB62)的吸附性能,探讨了吸附剂用量、初始pH、染料初始浓度、温度和吸附时间等因素对吸附效果的影响,研究了两种吸附剂的吸附动力学、吸附等温式和吸附热力学,实验结果表明:海泡石对染料有较强的吸附能力,用马氟炉焙烧活化能改善海泡石的吸附性能,提高其吸附能力。影响海泡石对染料吸附的因素有:吸附剂用量、pH、染料溶液初始浓度、温度和吸附时间。增加吸附剂用量和吸附时间、降低染料初始浓度和降低pH都能提高对染料的去除率,但吸附量却随着吸附剂用量的增加和pH的升高而降低,随着染料溶液初始浓度的增加而增加。随着温度的增加,AR57的去除率和吸附量都降低;而AB62的去除率和吸附量都增加。298K时,两种吸附剂对两种染料的吸附效果依次为:热改性海泡石吸附AB62>热改性海泡石吸附AR57>天然海泡石吸附AB62>天然海泡石吸附AR57。两种吸附剂对两种染料吸附速率都较快,前5min时的去除率和吸附量上升最快,90min时吸附基本达到平衡,吸附动力学都符合Lagergren准二级反应模型,对AR57的吸附等温式同时符合Langmuir和Freundnich方程,对AB62的吸附等温式符合Freundnich方程。热力学分析表明,海泡石吸附AR57时,ΔH<0, GΔ<0,ΔS<0,且|ΔH|>40 kJ/mol,因而是自发放热过程,反应以化学吸附为主,降低温度有利于吸附,吸附后体系变得更加有序;海泡石吸附AB62时,ΔH>0,ΔG<0,ΔS>0,且ΔH <40 kJ/mol,因而是自发吸热过程,反应以物理吸附为主,升高温度有利于吸附,吸附后体系变得更加紊乱。更多还原

【Abstract】 The adsorption performance of two dyes,acid red 57 and acid blue 62,on natrual sepiolite and heating sepiolite were studied by research.The effects of the dosage of sorbent、initial pH value、initial concentration of dye、temperature and adsorption time on the adsorption were discussed.Also, adsorption dynamics and adsorption uniform temperature types of two kind of absorbent were studied.The research conclusions indicated:Sepiolite had strong adsorption performance. Heating actived by muffle could improve and enhace adsorption capacity of sepiolite. The factor that affecting the adsorption of dyes on sepiolite included: dosage of sorbent、pH、initial concentration of the dye、temperature and adsorption time.The removal of acid dyes onto sepiolite as an adsorbent was increased by decreasing pH and ionic strength ,and by increasing sorbent dosage and adsorption time, while, the adsorption capacity of dyes was increased by decreasing sorbent dosage and pH value,and by increasing ionic strength.The adsorption ability of acid red 57 onto sepiolite as an adsorbent was decreased by decreasing temperature while the adsorption ability of acid blue 62 was increased with higher temperture. When the temperature was 298K,the adsorbing effective of the two sorbents were adsorbing of acid blue 62 onto heating sepiolite > adsorbing of acid red 57 onto heating sepiolite> adsorbing of acid blue 62 onto natural sepiolite > adsorbing of acid red 57 onto natural sepiolite.The rate of adsorption of two dyes on the two sorbents were rapid . The removal and adsorption capacity of dyes rose rapidest at the begin of 5min.The adsorption equilibrium was nearly reached at 90min.The adsorption dynamics of two dyes on the two sorbents all followed the law of the second-order eqution of Lagergren. The adsorption isotherm date of acid red 57on sepiolite fitted the Freundlich and Langmuir adsorption isotherm both well,and the adsorption isotherm date of acid red 57 on sepiolite fitted the Freundlich isotherm better than Langmuir isotherm.The thermodynamic analysis indicated :on the one hand,the standard thermodynamic function changes of the adsorbtion of acid red 57 onto sepiolite wereΔH<0,ΔG<0,ΔS<0, which explained that the adsorption was a spontaneous exothermic process. At the same time,the adsorption enthalpy changes absolute value was higher than 40kJ/mol which showed the adsorption was primarily due to chemical adsorption and the reduced temperature was advantageous to the adsorption.After the adsorption, the system became order even more;on the other hand, the standard thermodynamic function changes of the adsorbtion of acid blue 62 onto sepiolite wereΔH>0,ΔG<0,ΔS>0, which expressed that the adsorption was a spontaneous endoergic process.The adsorption enthalpy changes value was lower than 40kJ/mol which explained that the adsorption was mainly due to physical adsorption and the increased temperature was advantageous to the adsorption.After the adsorption ,the system became disorder even more.更多还原