改性钛白石膏对阳离子染料罗丹明B的吸附性能

Adsorption characteristics of cationic dye RhB on modified titanium gypsum

通过不同温度煅烧改性实验比较,选择用800℃煅烧的钛白石膏作为吸附剂,研究其对阳离子染料罗丹明B(Rhodamine B,RhB)的吸附特性。利用XRD,SEM,BET对改性钛白石膏进行表征,考察了溶液pH,温度,接触时间,投加量对吸附的影响。结果表明,当RhB溶液质量浓度为9.58 mg/L,pH值为7.0,吸附剂投加量为2 g/L,吸附时间为150 min时,改性钛白石膏对RhB的最大吸附量为2.3 mg/g,较原土提高了140.1%左右。溶液温度和吸附剂投加量对钛白石膏吸附RhB吸附有很大的影响。利用准一阶,准二阶动力学模型对吸附数据进行模拟,发现该吸附过程更符合准二阶动力学模型,Langmuir和Freundlich两种吸附等温模型都能较好地描述改性钛白石膏吸附RhB的过程。通过热力学计算,得到△H0为18.5kJ/mol,△G0<0,表明该吸附反应为自发进行的吸热反应。

By comparing the different modified methods,the titanium gypsum calcinated at 800℃ was chosen as an adsorbent to study its adsorption characteristics with Rhodamine B（RhB）.The prepared titanium gypsum was characterized by X-ray diffraction（XRD）,scanning electron microscope（SEM） and BET.The effects of pH,temperature,contact time and adsorbent dosage on RhB adsorption were investigated.The maximum uptake of 9.58 mg/L RhB was 2.3 mg/g with 2 g/L adsorbent,150 min contact time and initial pH value 7.0.which was improved about 140.1% over the original soil.Temperature and adsorbent dosage showed great effect on the adsorption process.Adsorption process well fitted the Langmuir isotherm model and the pseudo second-order kinetics model.The thermodynamic parameters such as enthalpy change △H0（18.5kJ/mol 0） and free energy change（△G0 0） indicated that the adsorption was a spontaneous and endothermic process.