509 / 2018-09-13 23:11:50

Extraction method of humic acid from excess sludge compost

全体主题 > 其它

Humic acid is a kind of macromolecular organic substance formed by chemical and biological transformation of animal and plant residues. It is widely distributed in soil, natural water, rivers, lakes, marine sediments, peat, lignite and weathered coal. And humic acid has an important influence on the adsorption, migration and transformation of organic and inorganic pollutants. Humic acid is extracted from homemade mature compost in this work, using base-dissolving acidification method. The effects of alkali liquor type, alkali liquor concentration, solide-liquid ratio, alkali dissolution time and reaction temperature on extracting humic acid are studied. And the extractive is characterized with scanning electron microscopy, Fourier transform infrared spectroscopy and elemental analysis technologies. The optimum technological conditions confirmed by experiments are as follows: the initial compost sample is mixed with (1+9) dilute hydrochloric acid in boiling water and heated for 60 min to remove impurities, and then is solubilized with 0.5 mol/L NaOH and NH4HCO3 aqueous alkali mixture in a volume ratio of 4:1 at 100 oC for 120 min, the solid-liquid ratio is 1:8, then its pH is adjusted to 1~2 with (1+1) dilute hydrochloric acid, and finally the target product is obtained after centrifugation. And the structure and application of humic acid is further studied. This study provides useful guidance for the extraction of humic acid and the secondary use of solid waste resources.