改性煤矸石基沸石对水中腐殖酸的吸附性能

Humic acid adsorption removal by modified coal gangue-based zeolite

以煤矸石为原料,采用NaOH碱熔水热合成法制备NaX型沸石,并采用阳离子表面活性剂双十二烷基二甲基溴化铵(DDAB)对其进行改性。采用比表面积测试法、X射线衍射仪、扫描电子显微镜和傅里叶变换红外光谱等表征手段对改性沸石(surfactant modified zeolite,SMZ)进行表征分析。选用CCD响应曲面法构建以腐殖酸(humic acid,HA)浓度、初始pH和改性沸石投加量为影响因素,HA去除率为响应值的预测模型,确定最佳吸附条件。结果表明,SMZ表面变得粗糙,DDAB成功负载到沸石外表面。各影响因素对吸附效果的影响顺序依次为:pH>HA浓度>吸附剂投加量。最佳吸附条件下的HA浓度为10mg/L、pH为4.55、改性沸石投加量为5.5g/L,此时对应的HA去除率为88.71%。本研究表明,煤矸石基改性沸石对HA的吸附性能明显提升,对去除水中HA具有潜在的应用价值。

NaX zeolite was synthesized from coal gangue using sodium hydroxide alkaline fusion hydrothermal method,and then modified by cationic surfactant didodecyldimethyl ammonium bromide(DDAB).Modified zeolite(SMZ)was characterized by BET,XRD,SEM and FTIR.Response surface methodology using central composite design(CCD)was used to investigate the effects of humic acid(HA)concentration,initial pH and adsorbent dosage on the removal effectiveness of HA by SMZ and determine the optimal adsorption conditions.The results showed that the surface of SMZ becomes rough,and DDAB was successfully loaded on the surface.The order of influencing factors on adsorption effect was as follows:pH>HA concentration>adsorbent dosage.An optimum adsorption conditions with 88.71%HA removal efficiency were HA concentration 10mg/L,pH 4.55,and adsorbent dosage(modified zeolite)5.5g/L.The adsorption capacity of modified zeolite for HA was significantly improved after modification,which had potential application value for HA removal from water.