Iron-based Hierarchical Mesoporous Materials:Synthesis,Characterization And Adsorption Performance For As(V)

Arsenic is a highly toxic element, which is a carcinogenicity-mutagenicity-teratogenicity contaminant, and is one of the contaminants prior to control. Along with the improvement of arsenic standard, the arsenic removal is a serious problem. The efficient, simple, economical method to arsenic removal is such a significant issue.Adsorption for its convenient, inexpensive, renewable advantage, have been widely used for arsenic removal. And adsorbent is the core of the adsorption. In this paper, Fe-MS, Fe-RMS, iron-aluminum composite were studied for arsenic adsorption.This paper includes the following sections:1Synthesis, characterization of Fe-RMS and its arsenic removal studyFe-RMS was synthesized by microemulsion method through the hydrolysis under alkaline condition. Fe-RMS was mesoporous microsphere which had a high surface area (1000m2/g), regular pore diameter (d=2.5nm). Through the adsorption performance, it showed that at pH=3～7, the initial As (V)=1000ppb, the As removal rate was good, the adsorption isotherm equation agreed well with Langmuir, Freundlich equation, the adsorption capacity was11.52mg/g. The adsorption kinetics agreed with the pseudo-second order rate equation, the adsorption mechanism was inner-sphere complex.2Synthesis, characterization of Fe-MS and its arsenic removal studyFe-MS was synthesized by hydrothermal method under the ultrasound- assisted condition. The X-ray diffraction (XRD) and scanning electron microscopy (SEM) demonstrated that Fe-MS was amorphous microsphere The nitrogen experiments indicated the specific surface area was407m2/g pore diameter was3.7nm and5.3nm. The adsorption experiments showed that at pH=3-4, the initial As (V)=100ppb, the As removal rate was above99%, the adsorption isotherm equation agreed well with Langmuir equation, the adsorption kinetics agreed with the pseudo-second order rate equation, the adsorption mechanism was inner-sphere complex.3Arsenic adsorption performance on Fe-Al compositeFe-Al composite was synthesized by grinding method. Through the adsorption performance, it showed that at pH=3-10, they still had high arsenic removal, the adsorption isotherm equation agreed well with Langmuir, Freundlich equation, the adsorption capacity (1.7mg、3.33mg/g、7.03mg/g) increased as the proportion of iron oxide increased (Fe:Al=1:9、5:5、9:1) The adsorption kinetics agreed with the pseudo-second order rate equation with the rise in the proportion of alumina (Fe:Al=1:9,5:5,9:1), pseudo-second kinetic constants also increased (0.4659g.mg-1· min-1,0.2571g.mg-1·min-1,0.1451g.mg-1·min-1).Compared to powered adsorbent, Fe-RMS, Fe-MS had a good hydraulic performance. The Fe-Al composite has the advantage in low cost, simplify, easy to operate of arsenic adsorbent. They all have a good prospect on arsenic removal.