Introduction

In this study, scientists from the Federal University of Fronteira Sul (Brazil) and the Comunitária University of the Chapecó Region (Brazil) discussed recent advances in the use of sustainable hydrogels modified with nanomaterials based on carbon, clays, and biomass residues, to remove pharmaceutical compounds from industrial wastewater, thanks to their adsorption capacity.

Adsorption is a valuable technique, due to its versatility and simplicity, for removing pharmaceutical compounds that are causing increasing concern due to their environmental persistence and documented concentrations in various regions of the world.

What Is a Hydrogel?

A hydrogel is a colloid (a liquid mixture containing solid particles in suspension, such as milk) formed by polymer chains (molecules with numerous bonds to carbon, hydrogen, and oxygen atoms) dispersed in water. Its main characteristic is its ability to retain water molecules thanks to its highly hydrophilic polymer chains (high affinity for water). It can be designed to withstand specific pressures and mechanical stresses, depending on its intended use.

The Problem of Pharmaceutical Pollution

Why Pharmaceutical Compounds Are Harmful?

Scientists point out that pharmaceutical compounds pose a problem for environmental pollution, as they are considered actual contaminants—particularly in industrial wastewater—due to their chemical stability and the limited effectiveness of conventional removal methods.

According to the graph presented in the paper, the five countries that have published the largest number of scientific studies focusing on adsorption and hydrogels for the removal of pharmaceutical compounds are: China, India, Iran, Brazil, and Malaysia. This is linked to growing concerns about the environmental impact of pharmaceutical compounds.

Industrial wastewater

Industrial wastewater consists of liquid discharges from large-scale industrial production activities. This wastewater must be treated in a targeted manner to ensure the efficient removal of contaminants.

The composition of industrial wastewater varies widely and may include high concentrations of organic substances, heavy metals, oils, fats, personal care products and other micropollutants. These compounds often persist even after treatment with conventional removal methods, depending on their physicochemical properties. The presence of these pharmaceutical contaminants has been documented in various regions of the world, such as the Ebro River delta in Spain and Guangzhou, China.

the effect of pharmaceutical compounds

The most common pharmaceutical compounds are: antibiotics, analgesics, and anti-inflammatory drugs. Even at low concentrations, they can cause harmful effects in aquatic organisms, such as physiological changes, chronic toxicity, and impacts across various trophic levels. Improper disposal of this wastewater can lead to prolonged exposure of aquatic organisms to complex pharmaceutical mixtures, making treatment more difficult. Higher concentrations are found in industrial wastewater than in urban and hospital wastewater.

The Solution: Use of Modified Hydrogels

Adsorption

Adsorption is a separation process and a physicochemical phenomenon in which pharmaceutical compounds accumulate on the surface of a solid or a liquid—in this case, on the surface of the hydrogel. Adsorption is a widely studied technique for removing pollutants due to its operational simplicity, efficiency, and versatility.

Furthermore, adsorption is a recognized technique that does not produce toxic byproducts during the removal of drugs, thereby ensuring a high level of environmental safety.

TYPES OF HYDROGELS

The use of modified hydrogels based on carbon, nanomaterials, clays, and biomass residues shows significant potential for making contaminant removal more sustainable. This is because their physicochemical properties can be adjusted to improve interaction with contaminants. According to the paper, these hybrid systems allow for a greater amount of contaminant to be adsorbed onto the surface.

Conventional Biological Processes

Conventional biological processes have limitations when it comes to the complete removal of pharmaceutical compounds, and in most cases, it is necessary to use adsorption and physical separation mechanisms to remove them completely. Biological and physicochemical processes (such as adsorption) represent the best current solution for the treatment of industrial wastewater.

The importance of the study

This study examines recent advances in the use of sustainable hybrid hydrogels modified with carbon-based materials, clays, and nanomaterials for adsorption. The paper provides an in-depth analysis of adsorption mechanisms, operational limitations, and scalability challenges across different hydrogel systems, with a focus on the limitations for industrial application.

The limitations of the Hydrogels

Despite the progress made, there are limitations regarding the use of hydrogels in terms of regeneration, scalability, and performance under real-world wastewater conditions. According to the paper, several other recent studies indicate that adsorption capacity alone is insufficient for evaluating the performance of the hydrogel, because there are other parameters to consider, such as the rate of surface regeneration and reuse efficiency.

Bibliographic sources:

1. Yago Vitório Colares Pinto, Bianca Trindade Oldoni, Kauê Câmara Leal de Oliveira, Suzana Fátima Bazoti, Gustavo Lopes Colpani, Eduardo Pavan Korf, Gean Delise Leal Pasquali. Adsorption applied to the removal of pharmaceuticals from industrial wastewater: Advances in the use of hydrogels as adsorbent materials. Next Chemical Engineering, 2026. DOI: https://doi.org/10.1016/j.nxcen.2026.100064

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