How Sugarcane Waste is Trapping Pharmaceutical Pollution
Imagine finishing a glass of water and wondering what tiny traces of medicines might be in it. Around the world, when we take common medications like anti-inflammatory drugs, our bodies don't use them completely. Small amounts get flushed away, eventually finding their path into rivers, lakes, and even drinking water.
Among these pharmaceutical pollutants is naproxen, a widely used pain reliever that's been detected in water sources globally.
Scientists have discovered that sugarcane bagasse - the fibrous waste left after juice extraction - can be transformed into a powerful water cleaner.
Even more remarkably, the very factors that make water "hard" or soapy can influence how well this material captures naproxen molecules. This is the story of how agricultural waste is being repurposed to tackle pharmaceutical pollution, creating a cleaner environment one sugarcane stalk at a time.
Naproxen belongs to a class of drugs known as non-steroidal anti-inflammatory drugs (NSAIDs), which are among the most widely used medications globally. After consumption, these drugs aren't completely metabolized by our bodies, and significant quantities are excreted and enter wastewater systems 1 .
Traditional water treatment plants weren't designed to remove these sophisticated chemical compounds, allowing them to pass through largely unaffected and enter aquatic environments 2 .
Among the most detected pharmaceutical contaminants in water systems worldwide
These pharmaceutical residues may exist in water at very low concentrations (typically nanograms to micrograms per liter), but their continuous introduction creates what scientists call "pseudo-persistent" pollution 3 .
Research has shown that naproxen and similar drugs can cause harmful effects on aquatic life, including embryotoxicity, genotoxicity, and reproductive inhibition in water fleas and fish 3 . While the human health impacts of long-term exposure to trace pharmaceuticals in water are still being studied, the potential risks including cellular process alterations and endocrine disruption have raised significant concerns 4 .
Sugarcane bagasse might seem like an unlikely solution to a complex pharmaceutical pollution problem. After the sweet juice is extracted from sugarcane stalks, what remains is a dry, pulpy fibrous material that has traditionally been treated as waste, often burned in fields or discarded. However, this "waste" is actually rich in cellulose, hemicellulose, and lignin - the perfect building blocks for creating porous, adsorbent materials 5 .
Sugarcane bagasse collected after juice extraction
Chemical and thermal treatment to create porosity
Development of functional groups for adsorption
Through a carefully controlled process involving heat and chemical treatments, scientists can transform this ordinary agricultural waste into what's known as porous sugarcane bagasse (PSB). This development process creates a material with a remarkably high surface area - 669.76 square meters per gram, which is roughly equivalent to the surface area of a basketball court packed into just two teaspoons of material 6 .
PSB Surface Area: 669.76 m²/g
Basketball Court: ~436 m²
This extensive surface area, filled with microscopic pores and tunnels, provides countless binding sites where naproxen molecules can be captured and removed from water.
The surface of this developed material contains hydroxyl and carboxylate groups - specific chemical structures that act like magnets for naproxen molecules, drawing them out of the water and holding them fast 6 . Spectroscopic analysis confirms that these functional groups play a crucial role in the adsorption process, making the material particularly effective at trapping pharmaceutical compounds.
To understand how well porous sugarcane bagasse removes naproxen from water, researchers conducted a comprehensive series of experiments examining how different water conditions affect the process 6 . The investigation looked specifically at three key factors: ionic strength (salt content), water hardness (primarily from calcium and magnesium ions), and the presence of surfactants (soap-like compounds commonly found in wastewater).
The research team developed PSB by treating raw sugarcane bagasse through a process that created a highly porous structure.
They conducted batch adsorption experiments, mixing measured amounts of PSB with naproxen-containing solutions under controlled conditions.
The experiments systematically varied ionic strength, water hardness, and surfactant presence to simulate different water conditions.
After allowing sufficient contact time, researchers measured remaining naproxen concentration and calculated adsorption efficiency.
They conducted regeneration experiments using microwave irradiation to test reusability of the PSB material.
The experiments revealed that changes in ionic strength, water hardness, and surfactant presence all significantly impacted naproxen removal efficiency 6 . Interestingly, unlike some adsorption processes that are hampered by complex water chemistry, PSB maintained effective naproxen removal across various conditions, though the efficiency varied depending on the specific factor being tested.
| Water Condition | Impact on Naproxen Removal | Practical Implication |
|---|---|---|
| Increased Ionic Strength | Significant impact on removal efficiency | Effective in both freshwater and brackish water |
| Water Hardness | Altered adsorption performance | Suitable for hard water areas |
| Surfactant Presence | Affected removal capacity | Works in wastewater containing detergents |
Thermodynamic analysis of the process revealed that naproxen adsorption onto PSB was spontaneous and exothermic (ΔG° = -5.50 kJ mol⁻¹), meaning it occurs naturally without requiring additional energy input 6 . The negative enthalpy value (ΔH° = -22.03 kJ mol⁻¹) confirmed the heat-releasing nature of the process, while the negative entropy change (ΔS° = -54.53 J mol⁻¹ K⁻¹) suggested that naproxen molecules become more ordered when attached to the PSB surface.
| Parameter | Symbol | Value | Interpretation |
|---|---|---|---|
| Enthalpy Change | ΔH° | -22.03 kJ mol⁻¹ | Exothermic process |
| Entropy Change | ΔS° | -54.53 J mol⁻¹ K⁻¹ | Increased order at surface |
| Gibbs Free Energy | ΔG° | -5.50 kJ mol⁻¹ | Spontaneous process |
Perhaps one of the most impressive findings was the material's regeneration potential. Using microwave irradiation, researchers achieved approximately 83% desorption of the captured naproxen, allowing the same PSB to be reused multiple times 6 . This dramatically enhances the economic viability and sustainability of the process.
Creating and testing porous sugarcane bagasse for water treatment requires several key materials, each serving a specific purpose in the development and adsorption process.
| Material/Reagent | Function in Research |
|---|---|
| Sugarcane Bagasse | Raw material for producing porous adsorbent |
| Potassium Hydroxide (KOH) | Chemical activator to develop porosity |
| Naproxen Standard | Target pollutant for adsorption studies |
| Sodium Chloride (NaCl) | Used to adjust ionic strength in testing |
| Calcium Salts | Simulate water hardness conditions |
| Surfactants | Test performance in detergent-containing water |
| Hydrochloric Acid & Sodium Hydroxide | Adjust solution pH for optimal adsorption |
The transformation of ordinary bagasse into a high-performance adsorbent relies heavily on chemical activators like potassium hydroxide. These compounds interact with the biomass during thermal treatment, creating and expanding the microscopic pores that give the material its exceptional surface area and adsorption capacity 7 .
The specific activation conditions can be tuned to optimize the pore structure for capturing different types of pollutants, making the process highly adaptable.
Key process for developing the porous structure in sugarcane bagasse
The development of porous sugarcane bagasse for naproxen removal represents more than just a scientific curiosity - it offers tangible economic and environmental benefits that could transform how we approach water treatment.
From an economic perspective, the production cost of PSB is remarkably low - approximately USD 19.49 per kilogram 6 .
Compared to conventional activated carbon, which can cost significantly more, this waste-derived material makes advanced water treatment more accessible, particularly for communities with limited resources. The regeneration potential further enhances cost-effectiveness by allowing multiple uses of the same material.
Environmentally, this technology represents a classic example of "trash to treasure" - converting an agricultural waste product that would otherwise contribute to disposal problems into a valuable resource for environmental protection 5 .
This circular approach not only addresses pharmaceutical pollution but also reduces the environmental footprint of sugarcane processing by finding productive uses for its waste streams.
Additionally, researchers explored energy recovery from naproxen-loaded PSB through combustion, finding that the spent material had a higher heating value of 14.15 MJ kg⁻¹ 6 . This suggests that after its useful life in water treatment, the material could potentially be used as an energy source, creating a comprehensive, waste-minimizing lifecycle.
MJ kg⁻¹
Heating ValueRegeneration
EfficiencyWaste Utilization
Circular ApproachThe story of using sugarcane bagasse to remove naproxen from water represents more than just an innovative solution to a specific pollution problem. It demonstrates a fundamental shift in how we view waste materials and their potential role in environmental protection. What was once considered agricultural residue is now a valuable resource with the power to clean our waterways.
This research opens doors to other exciting possibilities. Similar approaches could be developed for removing other pharmaceuticals, personal care products, and industrial chemicals that currently evade conventional water treatment methods.
The principles learned from studying how ionic strength, hardness, and surfactants affect adsorption could guide the design of even more effective materials in the future.
As scientific understanding grows and technology advances, solutions like porous sugarcane bagasse move us closer to a more sustainable relationship with our planet - one where we not only minimize our pollution but also harness natural materials and processes to heal the environmental damage we've already done. In the end, the journey from sweet juice to clean water reminds us that sometimes, the solutions to our most modern problems can be found in nature's timeless wisdom.