摘要
以硅藻土为主要原料,添加超细碳粉、烧结助剂和粘结剂,按一定比例混合、搅拌、造粒,在设定程序下煅烧,制备了硅藻土基多孔吸附填料(DBPAF),探讨了烧成温度、造孔剂添加量、硅藻土粉体粒径对DBPAF孔隙特征的影响,运用扫描电子显微镜(SEM)和X射线衍射仪(XRD)对DBPAF的微观形貌和物相组成进行了观察和分析,采用动态吸附实验研究了DBPAF的可操作性,采用静态吸附实验研究了DBPAF吸附Pb2+的性能和机制.结果表明,最适烧成温度范围为900~1000℃,最适造孔剂添加量为7.0%,最适硅藻土粉体粒径为2.40μm;与硅藻土原土(粉体)相比,DBPAF的可操作性明显提高,孔隙结构得到了明显改善,物相组成以方石英相为主.研究还表明,烧制过程升温速率以2~5℃/min为宜以保证DBPAF气孔分布均匀;DBPAF对Pb2+吸附容量较硅藻土原土(粉体)提高了78.0%,吸附过程速率控制步骤为Pb2+与DBPAF孔道内的基团发生的化学反应,吸附动力学符合拟二级动力学模型.
Diatomite-based porous adsorption filler（DBPAF） was prepared by the addition of superfine carbon,sintered additive and binder into the diatomite through a established process in which these materials above were mixed,stirred and granulated with a particular ratio.In this paper,the effects of sintering temperature,carbon dose and diatomite particle size on the porosity characteristic of DBPAF were studied.Micro-morphology and phase composition of DBPAF were observed and analyzed by SEM and XRD.Further more,DBPAF’s maneuverability,adsorption property and relative adsorption mechanism of Pb^2＋ were studied by dynamic and static adsorption experiment,respectively.As the results indicated,the optimal value of sintering temperature,carbon addition and diatomite particle size were 900~1000℃,7.0%,2.40μm,respectively.The maneuverability of DBPAF was significantly improved compared with natural diatomite and the porosity characteristic of DBPAF,whose the main phase was cristobalite,also obtained a certain degree of improvement.The results also illustrated that the optimum rate of temperature increase should be 2-5 ℃ /minto ensure the pores distributing uniformly in DBPAF.In other side,the adsorption capacity of DBPAF increased by 78.0% compared with natural diatomite.Elementary mechanism studies implied that the key procedure of adsorption on Pb^2＋ of DBPAF was the chemical reaction happened in the channels of DBPAF where Pb^2＋and active groups might react mutually.Further,the kinetic mode of Pb^2＋adsorption on DBPAF followed Pseudo-second-order.
出处
《中国环境科学》
EI
CAS
CSCD
北大核心
2012年第12期2205-2212,共8页
China Environmental Science
基金
湖南省自然科学省市联合基金重点项目(12JJ8016)
湖南省研究生科研创新项目(CX2012B317)
湖南省环境科学重点学科建设基金资助项目(2006180)
关键词
硅藻土
多孔吸附填料
孔隙特征
吸附
PB2+
diatomite
porous adsorption filler
porosity characteristic
adsorption
Pb^2＋
