An efficient technique for the purification of fulvic acid extracted from leonardite

Abstract

Fulvic acids (FAs) are significant natural organic compounds produced during the decomposition of plants and animals. There is great demand for FAs in pharmaceutical, cosmetic, and industrial applications. However, their use is declining due to the tedious purification process. This study developed a method to purify FAs extracted directly from leonardite-rich humic substances. The method introduces a permeation cell integrated with a polymer inclusion membrane to separate target impurities related to FAs from extractants and humic raw material sources. Polymeric membranes were prepared using fixed proportions of cellulose triacetate, tri octyl methylammonium chloride, tributyl phosphate, and 2-nitrophenyl pentyl ether. The purified fulvic acids, feed phase, and stripping phase products were characterized using SEM, EDX, FTIR, and UV-Vis. Fluorescence spectroscopy analysis was also performed to compare the purity intensity of fluorescence spectra of the respective components of the feed and stripping phase. In terms of purification, the membrane obstructed the passage of foreign ions and unwanted particles and allowed only FAs molecules to pass through. This research affirms that the present method is more effective, cheaper, and more convenient than the classical method for FAs purification.