Journal of Molecular Pharmaceutics & Organic Process Research
Open Access

Pharmaceutically active compounds; Aqueous solutions; Wastewater treatment; Adsorption; Membrane filtration; Biodegradation; Advanced oxidation processes; Environmental impact; Hybrid processes

Introduction

Pharmaceutically Active Compounds (PhACs) have emerged as a class of pollutants in water systems worldwide. These substances, commonly used in human and veterinary medicine, include a wide range of drugs such as antibiotics, anti-inflammatory drugs, hormones, and pain relievers. The presence of PhACs in aqueous environments is primarily due to incomplete metabolism in humans and animals, improper disposal, and the inability of conventional wastewater treatment systems to completely eliminate these compounds. PhACs are highly persistent in the environment due to their complex molecular structures, making their removal from water challenging. Moreover, many of these compounds are bioactive at low concentrations, posing potential risks to aquatic organisms, human health, and ecosystems. As a result, the removal of PhACs from aqueous solutions has become a critical area of research in environmental science and wastewater treatment [1,2].

Description

Adsorption

Adsorption is one of the most widely researched methods for removing PhACs from aqueous solutions. This process involves the accumulation of PhAC molecules on the surface of solid adsorbents, such as activated carbon, biochar, or polymeric materials. The effectiveness of adsorption depends on the physicochemical properties of the adsorbent, including surface area, pore structure, and surface charge. Activated carbon, in particular, is widely used for its high surface area and excellent adsorption capacity for a wide range of PhACs. However, the regeneration and disposal of spent adsorbents pose additional challenges, limiting the sustainability of this method in large-scale applications [3].

Membrane filtration

Membrane filtration techniques, such as reverse osmosis (RO) and nanofiltration (NF), are also employed to remove PhACs from water. These processes rely on semipermeable membranes that allow water molecules to pass through while retaining dissolved contaminants. RO membranes are particularly effective at removing a broad range of organic and inorganic compounds, including PhACs. While membrane filtration offers high removal efficiency, it is often hindered by issues such as membrane fouling, high energy consumption, and the need for frequent maintenance and replacement of membranes. Furthermore, the disposal of concentrated reject streams containing pollutants is an environmental concern [4].

Biodegradation

Biodegradation, the process by which microorganisms break down organic compounds, is an environmentally friendly method for PhACs removal. Several bacterial and fungal strains have been identified for their ability to degrade specific PhACs in aquatic environments. Biodegradation is advantageous due to its low cost and sustainability, as it utilizes naturally occurring microorganisms. However, biodegradation processes are often slow and may be limited by the toxicity of certain PhACs to microorganisms. To overcome these limitations, the use of genetically modified microbes or the application of co-substrates to enhance microbial growth has been explored [5].

Advanced oxidation processes (AOPs)

Advanced oxidation processes (AOPs) involve the generation of highly reactive hydroxyl radicals (•OH) to degrade organic pollutants, including PhACs. AOPs, such as ozonation, UV/H2O2, and Fenton’s reagent, are highly effective in breaking down complex PhAC molecules into smaller, less harmful compounds. Despite their high efficiency, AOPs require significant energy input and may generate secondary pollutants. The high cost of oxidants and reagents also limits the large-scale application of AOPs for PhAC removal in wastewater treatment plants [6].

Hybrid processes

To address the limitations of individual removal methods, hybrid processes that combine two or more treatment technologies have been developed. For instance, combining adsorption with AOPs can enhance the removal efficiency and reduce operational costs. Other hybrid systems include combining membrane filtration with biological treatment or integrating photocatalysis with electrochemical processes. Hybrid processes have shown promising results in achieving higher removal efficiencies and addressing the challenges associated with single-method approaches. However, the optimization of these systems for real-world applications remains an area of ongoing research [7].

Results and Discussion

Recent studies have highlighted the effectiveness of various PhACs removal techniques, with adsorption and membrane filtration leading the field due to their high removal rates. For instance, activated carbon has been shown to effectively adsorb a wide range of PhACs, with removal efficiencies ranging from 70% to 99%. Similarly, membrane filtration techniques like reverse osmosis have been reported to remove PhACs with efficiencies exceeding 90%, depending on the specific compound. Biodegradation, while effective for certain PhACs, has demonstrated more limited success, particularly with more complex or persistent compounds. Recent advancements in genetically engineered bacteria and fungi have shown promise in enhancing biodegradation efficiency. However, the slow kinetics of microbial degradation and the potential toxicity of residual compounds remain significant challenges [8,9].

AOPs have demonstrated high efficiency in breaking down PhACs, but their high energy requirements and cost remain barriers to widespread adoption. Hybrid processes combining AOPs with adsorption or biodegradation have been shown to improve performance, offering a more sustainable solution to PhAC removal. The environmental impact of PhACs in aquatic environments necessitates the development of more efficient and cost-effective removal methods. The future of PhACs removal lies in the integration of advanced techniques and the development of innovative hybrid systems that can achieve high removal efficiencies while minimizing operational costs [10].

Conclusion

The removal of pharmaceutically active compounds from aqueous solutions is a crucial aspect of environmental protection and water quality management. While Snumerous removal technologies exist, each has its own set of advantages and limitations. Adsorption, membrane filtration, biodegradation, and advanced oxidation processes represent the most promising methods, with hybrid systems offering the potential to improve efficiency and sustainability. Future research should focus on optimizing these methods, addressing their limitations, and exploring novel approaches for large-scale implementation in wastewater treatment facilities. Enhanced collaboration between researchers, industries, and policymakers will be essential for the development of effective and sustainable solutions for PhACs removal.

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