| dc.description.abstract | In this study, ashes of water purification sludge and waste glass, two materials in which aluminum and silicate are abundant, were used as the source of silicone and aluminum to synthesize MCM-41 via the alkaline fusion method coupled with the traditional hydrothermal approach. In addition, surfaces of the MCM-41 particles were subsequently amino-functionalized for the application of chromate adsorption under acidic conditions (pH~3). The synthetic MCM-41 was characterized with a combination of SAXS, ASAP, TEM, SEM, FTIR, 29Si-NMR and EA techniques. Multiple lines of evidence first confirmed the success of the preparation processes, including (i) the observation of the signature peaks from the SAXS spectrum; (ii) the appearance of the ordered hexagonal holes from the TEM images; as well as (iii) the mesoporous property identified from the BET analysis, showing that the specific surface area of the particles was up to 839 m2/g. Further, FTIR, 29Si-NMR and EA measurements showed that the amine-refluxing method indeed resulted in the amino-functionalization on the MCM-41 surface, with 8-hr refluxing better than 24-hr. Results of the adsorption experiments conducted under acidic conditions showed that surface modification on the MCM-41 did lead to a higher chromate sorption efficiency, presumably due to the electrostatic interaction between the positively-charged surface of MCM-41 and the chromate anions at pH 3. Moreover, the adsorptive behavior was best explained by the Freundlich model, suggesting that the surface adsorption sites were not evenly distributed and the potential energy were not the same. Taken together, these results suggested that water sludge ashes and waste glass can be alternative sources of silicon and aluminum for MCM-41 synthesis, and adsorption of negatively-charged metal species such as chromate on to MCM-41 can be enhanced through appropriate functionality alternation on the surface of MCM-41. | en_US |