The Adsorption Of Acid And Basic Dyes On Iron Modified Mesoporous Silica Microspheres

Dye wastewater has a series of disadvantages such as complex composition, deepcolor, high toxic and difficult to biodegradate. When discharged into the environmenstreams, it could lead to eutrophication and affect aquatic organisms and microbialgrowth.. And heavy metal in the wastewater would continue to pass through the foodchain and accumulate in the human body, which is carcinogesis. When dischargeddirectly without depth treatment, it would pose a great threat to human, animals andplants. Moreover, the production of dyes toward anti-photolysis, anti-oxidation andanti-biodegradable direction, and dye wastewater is difficult to deal with using thegeneral water treatment system, therefore people began to try out some new techniquesto dye wastewater treatment.Mesoporous molecular sieves possess high surface areas, ordered and tunable porechannels, and modifiable hole surfaces, which are widely used in the fields of selectiveadsorption, efficient catalysis, biopharmaceutical, and so on. Meanwhile, it has a seriesof advantages such as Si-O and Si-OH combined with a variety of organic, whichmake modified mesoporous materials to be a focus for adsorpting acid and base organicdye.In the first part, ferrous sulfate (FeSO4) as the iron source, Mesoporous silicamicrospheres doped with three different iron content（0.1Fe-MSM，0.3Fe-MSM，0.5Fe-MSM） were synthesized by one step method in room temperature. The structure ofmesoporous materials were characterized and detected the contect of Fe by means ofX-ray diffraction (XRD)、infrared spectrum (IR)、N2adsorption-desorption、scanningelectron microscopy (SEM) and atomic absorption (AAS). The effects of the adsorbentdosage, adsorption time, initial dye concentration and pH on the basic methyl violet(MV) dye adsorption performance were analyzed, which obtained apparent kineticsequation and related parameters, and discussed adsorption mechanism. The resultsindicate that adsorption performance reaches greately99%under the conditions of theinitial concentration of50mg/L MV solution, adsorbent dosage of10mg0.1Fe-MSM,the adsorption equilibrium time for30min and pH of alkalescence. The adsorptionprocess obeyed the pseudo-second-order kinetic model, and intraparticle pore diffusionwere rate-controlling steps.In the second part, ferric ammonium sulfate (NH4Fe (SO4)2.12H2O) as the iron source, mesoporous silica microspheres doped with different iron content (Fe-MSM)were synthesized by one step method in room temperature and were characterized. Theeffects of the adsorbent dosage, adsorption time, initial dye concentration and reactiontemperature on the acid methyl orange (MO) dye adsorption performance were analyzed,and the adsorption thermodynamic was also investigated. The results show that the Fecontent has little influence on the adsorption effect of MO. Adsorption effcient ofFe-MSM increases with increasing adsorption time, initial concentration and reactiontemperature. And0.3Fe-MSM adsorption performance reaches greately90.2%underadsorbent dosage of60mg, the stirring reaction time for45min at60℃, the conditionsof the initial concentration of300mg/L MO solution. Freundlich adsorption isothermequations was found bo be appropriate for the adsorption process.