In many developing countries, including Bangladesh, waste management presents a significant environmental hurdle, often leading to widespread pollution of air, soil, and water due to inadequate segregation practices. However, this abundance of waste also holds untapped potential for beneficial applications, particularly through the creation of biocharBiochar is a carbon-rich material created from biomass decomposition in low-oxygen conditions. It has important applications in environmental remediation, soil improvement, agriculture, carbon sequestration, energy storage, and sustainable materials, promoting efficiency and reducing waste in various contexts while addressing climate change challenges. More, a carbon-rich material produced by heating biomassBiomass is a complex biological organic or non-organic solid product derived from living or recently living organism and available naturally. Various types of wastes such as animal manure, waste paper, sludge and many industrial wastes are also treated as biomass because like natural biomass these More in the absence of oxygen. A recent PhpH is a measure of how acidic or alkaline a substance is. A pH of 7 is neutral, while lower pH values indicate acidity and higher values indicate alkalinity. Biochars are normally alkaline and can influence soil pH, often increasing it, which can be beneficial More.D. thesis by Islam Md Rezwanul, titled “APPLICATION OF WASTE-DERIVED BIOCHAR FOR IMPROVING SOIL CHEMICAL PROPERTIES AND REMOVING HARMFUL PHARMACEUTICALS,” explores this potential, demonstrating how everyday food waste can be transformed into valuable resources for soil improvement and pollutant removal. This comprehensive study was conducted in a laboratory setting.

The research systematically characterized eight types of edible food waste, including brinjal waste, potato peels, banana peels, orange peels, eggshells, cow bone, chicken bone, and fish bone. The goal was to understand their composition and suitability for producing biochar. Interestingly, the study found that fruit waste had higher fixed carbon content (11.33-14.27%) compared to animal waste (1.01-2.83%), excluding eggshells (22.48%). Animal waste, apart from eggshells, contained more nitrogen (3.82-5.06%). The highest phosphorus concentration was found in the combined fruit sample (28.21% ± 8.451%), followed closely by banana peels (24.96% ± 11.644%). Vegetable waste showed significantly higher potassium levels (24.90% ± 28.311-37.92% ± 24.833%) compared to other waste types. Eggshells were rich in calcium (68.82% ± 10.778%), while fish bone waste contained the most magnesium (15.37% ± 29.88%). These findings indicate that non-edible food waste could serve as a valuable source of essential plant nutrients for soil applications.

A significant part of the study focused on the efficacy of waste-derived biochar in removing pharmaceutical contaminants from water. Pyrolyzed eggshells, specifically those produced at 600°C (PES-600), demonstrated remarkable efficiency in removing ciprofloxacin (CIP), achieving the highest removal rate of 86.06% ± 2.25%. The optimal performance was consistently observed at an initial CIP concentration of 125 mg/L. This adsorption capacity peaked at pH 5 (5.84 ± 0.1 mg/g), suggesting that interactions like hydrogen bonding, π-π interactions, and ion exchange played a crucial role. Scanning electron microscope images confirmed that PES-600 possessed the highest number of pores, contributing to a smoother surface after adsorption.

Similarly, biochar derived from banana peels (BPB900), produced at 900°C, exhibited the highest ibuprofen removal efficiency of 69.28% ± 0.83% at a 125 mg/L concentration. The maximum removal efficiency for ibuprofen reached 72.67% ± 0.75% at pH 9. FTIR analysis confirmed the presence of functional groups (hydroxyl, carboxylic, carbonyl, and aromatic rings) that are essential for the adsorption process. These results underscore the effectiveness of both pyrolyzed eggshells and banana peel biochar as superior adsorbents for pharmaceutical contaminants compared to other tested materials.

Beyond contaminant removal, the research also investigated the impact of waste biomass and its biochar on soil chemical properties. The application of combined food waste and microplastics, along with their biochars, demonstrated a notable buffering effect, stabilizing or slightly increasing the soil pH towards neutrality, with values ranging from 5.95 to 6.27. While electrical conductivity (EC) generally increased across all treatments, the rise was particularly significant in soils treated with a combination of food waste-derived biochar and microplastics. Some treatments involving the combination of food waste and microplastics (FW+MP) and their biochar (FW+MP)B showed higher carbon content (up to 7.48%) and nitrogen content (0.52%). Furthermore, soil treated with microplastics combined with their biochar exhibited a lower concentration of nitrate (NO3-) ions, and sulfate (SO4^2-) ion concentrations decreased across all treatments due to solubility.

A novel aspect of this study involved the use of machine learning algorithms to predict the removal efficiency of pharmaceutical contaminants. For ciprofloxacin removal using pyrolyzed eggshells, the machine learning algorithms achieved a remarkable accuracy level of 90.28%. Similarly, for ibuprofen adsorption using banana peel biochar, machine learning algorithms, especially Random Forest (RF), demonstrated outstanding performance with 90.07% accuracy in predicting experimental data. These high accuracy levels validate the predictive power of machine learning in optimizing biochar-based adsorption processes.

Overall, this thesis underscores the immense potential of waste-derived biochar not only as a source of plant nutrients but also as a powerful tool for environmental remediation. The findings pave the way for sustainable waste management practices, offering cost-effective and eco-friendly solutions for improving soil health and mitigating pharmaceutical pollution in aquatic systems. Further research is recommended to explore the practical application of biochar in wastewater treatment and to assess the long-term environmental risks posed by pharmaceutical pollutants for sustainable soil management.

Source: Islam Md Rezwanul. (2025). APPLICATION OF WASTE-DERIVED BIOCHAR FOR IMPROVING SOIL CHEMICAL PROPERTIES AND REMOVING HARMFUL PHARMACEUTICALS (廃棄物由来のバイオチャーを用いた土壌化学特性の改良と有害医薬用化学物質の除去) (Doctoral thesis).