# Synthesis and Characterization of Composite Materials Based on Sodium Humate and Poly(vinyl alcohol)

## TL;DR

This paper describes a new method to create polymer composites using PVA and sodium humate, which can be used to treat wastewater by removing heavy metals.

## Contribution

The study introduces a novel approach to macromolecular design using HNa to control polymer structure and improve adsorption properties.

## Key findings

- Adding 2–10% HNa reduces gelation time and increases viscosity, indicating accelerated polymer network formation.
- AFM analysis shows HNa increases composite surface smoothness and structural homogeneity.
- The composite achieves a maximum sorption capacity of 3.40 mmol/g for Cu(II) ions.

## Abstract

This article presents a method for synthesizing a polymer composite based on the interaction of PVA and HNa isolated from coals from the Shubarkol deposit (Karaganda, Kazakhstan). The study focuses on the macromolecular aspects of the formation of the polymer matrix structure and the effect of a natural modifier on the properties of the composite. Taking into account the concept of macromolecular design, the addition of small additives of HNa (2–10%) significantly changes the nature of intermolecular interactions in the solution, promoting the accelerated structuring of the polymer network. This is manifested in a decrease in the gelation time, which is confirmed by a kinetic analysis based on changes in the relative viscosity of the systems. It was found that the greatest increase in viscosity is achieved on the fifth day with a content of 10% HNa and pH = 7, which, on the fifth day, indicates a critical concentration of the modifier necessary for the formation of a stable spatial network of hydrogen bonds and ion-dipole interactions between the functional groups of PVA and HNa. Morphological studies using AFM showed that an increase in the HNa content leads to a significant smoothing of the composite surface, indicating the formation of a more homogeneous and dense structure. These changes are due to the reorganization of the macromolecular architecture under the influence of modifying additives. The adsorption characteristics of the composite were estimated by the maximum sorption capacity, which was 3.40 mmol/g for Cu(II) ions. The results emphasize that the targeted control of the structure at the macromolecular level allows the creation of polymeric materials with specified physicochemical properties that are effective for wastewater treatment from heavy metals. The study demonstrates the potential of macromolecular design as a tool for the development of polymer composites with improved performance characteristics and environmental significance.