TY - JOUR AU - Jovanović, Uroš AU - Marković, Mirjana AU - Čokeša, Đuro AU - Živković, Nikola AU - Radmanović, Svjetlana PY - 2022/03/23 Y2 - 2024/03/29 TI - Self-aggregation of soil humic acids with respect to their structural characteristics: Scientific paper JF - Journal of the Serbian Chemical Society JA - J. Serb. Chem. Soc. VL - 87 IS - 6 SE - Environmental Chemistry DO - 10.2298/JSC211125010J UR - https://shd-pub.org.rs/index.php/JSCS/article/view/11409 SP - 761-773 AB - <p>The main goal of this work was to estimate the influence of carboxyl and phenolic groups, as well as aromatic, aliphatic and polysaccharide compo­nents, on the soil humic acids (HA) self-aggregation process. Soil HAs (lepto­sol and regosol) were separated using base resin getting fractions with different functional group contents. Blocking of carboxyl groups was performed using the esteri­fication procedure to estimate the participation of each functional group in the HA aggregation. The presence of HA structural components was evaluated by potentiometric titration and ATR-FTIR. The aggregation was monitored at pH 3 using dynamic light scattering. Results indicated that the higher group content, the HA aggregation is less pronounced. A significant positive correlation of aliphatic C and aggregate size revealed their dominant influence in the HA self-aggregation. A lower abundance of aliphatic C in HA fractions could be considered as not sufficient to start the process. An increase of aromatic C in esters likely pointed out to its participation in hydrophobic bonding and, consequently, more pronounced aggregation. The relation of HA self-aggregate size with carboxyl and phenolic group, as well as aliphatic C, at low pH, could be considered universal regardless of the structural charac­ter­istics of the original or modified HA forms.</p> ER -