Mechanochemical modification of the structure of brown coal humic acids for preparing a sorbent for heavy metals

Abstract

Mechanochemical modification of the structure of brown coal humic acids with classical base (NaOH) and oxidizing base (Na2CO3·1.5H2O2) reagents was studied. Treatment of brown coal under these conditions leads to an increase in the degree of recovery of humic acids without breaking the macrostructure of the molecules. The reaction with the base reagent leads to an increase in the content of carboxy groups at hydrocarbon chains, whereas the action of the oxidizing base reagent leads to an increase in the content of phenolic and carboxy groups at aromatic rings, with the formation of chelating structures. The samples obtained show high performance as sorbents for heavy metals.