摘要
The structural change and mineralogy of Al gel during aging time were investigated by using spectroscopy techniques.The results indicated that:1) the aggregation extent of solution-gel system increases with aging time,and the structure of amorphous gel becomes more short-ordered;2) after six months,the gel formats nordstrandite and little gibbsite;3) a marked decrease in the number of(Al-OH)oh bands occurring at 610 cm-1 and increase in the number of(Al-OH2)oh bands occurring at 555 cm-1 indicate that the gel undergoes rearrangement-like process during aging;4) the gel constantly contains Al-O tetrahedron of Keggin structure,but the signal peak occurring at ≈61×10-6 of 27Al MAS NMR have a slight shift to downfield with aging time.A mineralogical transformation mechanism for hydrolysis Al(Ⅲ) solution was proposed.
The structural change and mineralogy of Al gel during aging time were investigated by using spectroscopy techniques. The results indicated that： 1） the aggregation extent of solution-gel system increases with aging time, and the structure of amorphous gel becomes more short-ordered; 2） after six months, the gel formats nordstrandite and little gibbsite; 3） a marked decrease in the number of （Al-OH）oh bands occurring at 610 cm^-1 and increase in the number of （Al-OH2）oh bands occurring at 555 cm^-1 indicate that the gel undergoes rearrangement-like process during aging; 4） the gel constantly contains Al-O tetrahedron of Keggin structure, but the signal peak occurring at =61×10^-6 of^ 27Al MAS NMR have a slight shift to downfield with aging time. A mineralogical transformation mechanism for hydrolysis Al（Ⅲ） solution was proposed.
基金
supported by National Natural Science Fund of China (Grant No. 40972110)
the specialized research fund for the doctoral program of Higher Education of China (Grant No. 2006029009)
the program for New Century Excellent Talents in Universities and Colleges (Grant No. NCET-07-0801)
