KHA/CTS/AA水凝胶型吸附剂的制备及对亚甲基蓝的吸附研究

Preparation of KHA/CTS/AA hydrogel and adsorption property for MB

以丙烯酸(AA)为单体,腐植酸钾(KHA)和壳聚糖(CTS)为原料,过硫酸钾(KPS)为引发剂,N,N-亚甲基丙烯酰胺(MBA)为交联剂,采用水溶液聚合法制备出KHA/CTS/AA水凝胶型吸附剂。采用扫描电子显微镜、傅里叶变换红外光谱仪、X射线衍射仪和物理吸附仪等对吸附剂的形貌、结构进行表征,通过吸附热力学和动力学对吸附阳离子染料亚甲基蓝(MB)的过程进行了研究。结果表明:KHA/CTS/AA对MB的吸附量随着初始质量浓度增大而提高,随着pH的升高先增加后逐渐减小,吸附量随着温度的升高而增加。KHA/CTS/AA用量为50mg,MB溶液为100mL,MB初始质量浓度为1050mg/L,pH=5,温度为318K时,吸附量达到最大值880.246mg/g。KHA/CTS/AA对MB的吸附符合Lagergren准二级动力学方程和Freundlich吸附等温模型。热力学分析结果表明,KHA/CTS/AA对MB的吸附机理主要包括静电引力、氢键、范德华力、离子交换等方式。

Acrylic acid(AA)used as monomer,potassium humate(KHA)and chitosan(CTS)as raw materials,potassium persulfate(KPS)as initiator,and N,N-bis methacrylamide(MBA)as crosslinking agent,KHA/CTS/AA hydrogel type adsorbent was prepared by aqueous solution polymerization.The morphology and structure of the composites were characterized by SEM,FT-IR,XRD and physical adsorber.The adsorption of cationic dye methylene blue(MB)by the composites was researched by adsorption thermodynamics and kinetics.The results shown that the adsorption amount for MB increased with the increase of the initial concentration,increased first and then decreased with the increase of pH value,and increased with the increase of temperature.When the composites was50 mg,the MB dye solution was 100 mL,C0=1050 mg/L,pH=5 and T=318 K,the adsorption amount reached a maximum value of 880.246 mg/g.The adsorption for MB conformed to Lagergren quasi-second-order kinetic equation and Freundlich-type adsorption isotherm model.The kinetic results indicated that the main control step for the MB adsorption rate of the composites was intraparticle diffusion.Thermodynamic results shown that the adsorption mechanism of the composites on MB dyes mainly included electrostatic attraction,hydrogen bonding,Van der Waals force and ion exchange.