Przemysl Chemiczny, Vol.90, No.5, 792-795, 2011
Evaluation of sorption capacity of humic acids as a factor in determining the possibility of their application for fertilizer production
Four domestic lignites were extd. with aq. solns. of NaOH, Na(4)P(2)O(7) and NaOH + Na(4)P(2)O(7) (1:1) at lignite-soln. ratio 1:20 by mass to recover humic substances. The exts. were fractioned into humic and fulvic acids. The humic acids were studied for adsorption capacity (hydrolytic acidity, base adsorption) and content of carboxylic and phenolic groups. The highest sorption capacity showed the humic acids recovered by using 0.1 M Na(4)P(2)O(7) but the highest sepn. yield was achieved by extn. with NaOH soln.