Preparation of diatomite-based porous adsorption filler and adsorption on Pb~(2+)

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 Pb2+ 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 Pb2+ of DBPAF was the chemical reaction happened in the channels of DBPAF where Pb2+and active groups might react mutually.Further,the kinetic mode of Pb2+adsorption on DBPAF followed Pseudo-second-order.