Ten grams of RHA samples were stirred
in 80 ml distilled 2.0, 2.5 and 3.0 N sodium
hydroxide solution, respectively. RHA was
boiled in a covered 250 ml Erlenmeyer flask
for 3 h. The solution was filtered and the
residue was washed with 20 ml boiling water.
The filtrate was allowed to cool down to
room temperature and added 5 N H2SO4 until
pH 2 and then added NH4OH until pH 8.5
allowed to room temperature for 3.5 h. The
filtrate was then dried at 120 oC for 12 h. Asreceived
product was finally investigated by
Fourier transform infrared (FTIR- model
tenser 27).