2.1 Materials
Aluminum nitrate nonahydrate
(Al(NO3)3·9H2O, 99%)
and 1,2,4,5-benzenetetracarboxylic acid (BTEC, 98%) were purchased from
Shanghai Aladdin Biochemical Technology Co., Ltd. Sodium hydroxide
(NaOH, 99%) and methanol (CH3OH, 99%) were provided by
Sinopharm Chemical Reagent Co., Ltd. The above reagents were used
directly without further purification. The distilled water used in our
experiments was prepared in our laboratory.
The synthesis and purification of MIL-120Al were performed according to
a previously reported method with some
modifications.40 The synthesis process was as follows:
Al(NO3)3·9H2O (3.2 g,
8.5 mmol) and BTEC (0.5 g, 2.0 mmol) were added to a 100 mL
polytetrafluoroethylene reaction kettle and 20 mL of water added using a
pipette. The above mixture was stirred at 298 K for 20 min. NaOH (0.54
g, 13.6 mmol) was added to the resulting mixture and stirring continued
at 298 K for 20 min. The resulting mixture was sealed in a
stainless-steel shell and placed in an oven. The oven temperature was
increased from room temperature to 473 K within 2 h and kept at 473 K
for 24 h. The reaction kettle was removed from the oven and allowed to
cool naturally to the room temperature. The white powder was collected
upon repeated centrifugation and thorough washing with 353 K distilled
water and 423 K CH3OH, and the product dried at room
temperature.
A large-scale synthesis of MIL-120Al was carried out as follows:
Al(NO3)3·9H2O (0.13 kg,
0.34 mol), BTEC (0.02 kg, 0.08 mol), and NaOH (0.02 kg, 0.56 mol) were
dissolved in 0.8 L of deionized water. The solution was stirred for 30
min and then placed in a 2 L stainless steel reactor for synthesis at
473 K for 24 h. After cooling down to room temperature, the sample was
filtered, washed with H2O/CH3OH (1/1,
v/v) solution at 423 K three times, and dried at room temperature. The
product was obtained with a yield of ~40–45 g.