This study evaluates the environmental and economic feasibility of walnut shell-derived biochar (W-BC) as a sustainable solution for metolachlor (MET) removal from contaminated water. The results demonstrate that W-BC achieves 87.89% removal efficiency with a saturated adsorption capacity of 96.15 mg g⁻¹, significantly outperforming biochars from cow dung (D-BC) and corn cobs (C-BC). This high performance is attributed to W-BC’s exceptional physicochemical properties: a specific surface area of 358.67 m² g⁻¹, total pore volume of 0.22 cm³ g⁻¹, and average pore diameter of 1.9 nm—features ideal for effective pore-filling and molecular interaction. These characteristics were confirmed through BET analysis, SEM imaging, and FTIR spectroscopy, which revealed abundant oxygen-containing functional groups (–OH, –COOH) and aromatic structures essential for chemical adsorption.
The process is environmentally benign: W-BC is produced via pyrolysis of agricultural waste under oxygen-limited conditions, converting low-value biomass into a high-value material without generating secondary pollutants. Unlike conventional adsorbents such as activated carbon or synthetic resins, which require energy-intensive manufacturing and fossil-based precursors, W-BC utilizes renewable, non-food biomass.135-16-0 References Its production aligns with circular economy principles by repurposing walnut shells—a byproduct of nut processing—into an effective water treatment medium. Moreover, W-BC is biodegradable and does not introduce persistent contaminants into ecosystems upon disposal.
Economically, W-BC offers significant advantages. Walnut shells are widely available and inexpensive, often discarded as waste. The pyrolysis process at 700 °C is energy-efficient and scalable, requiring minimal preprocessing. Compared to commercial adsorbents costing $5–$20 per kg, W-BC can be produced at a fraction of the cost, potentially below $2 per kg when scaled. Its high adsorption capacity reduces the required dosage—only 0.20 g L⁻¹ needed for optimal performance—further lowering operational costs. Regeneration studies show that W-BC retains over 50% of its capacity after two cycles, enabling reuse and extending material lifespan while minimizing waste.
The system is also operationally simple: equilibrium is reached in just 30 minutes, allowing rapid treatment cycles. It functions effectively across a range of pH levels (optimal at pH 3.0–7.0), making it adaptable to diverse water sources.147127-20-6 Molecular Weight Ionic strength effects are manageable, with moderate Na⁺ concentrations enhancing removal through salting-out effects, while higher levels can be mitigated by pretreatment.PMID:27809433
Compared to other technologies—such as advanced oxidation, membrane filtration, or electrochemical methods—adsorption using W-BC is simpler, safer, and more cost-effective. It requires no complex equipment, avoids secondary pollution, and operates under ambient conditions. Its performance surpasses many reported materials, including rice straw biochar (29.97 mg g⁻¹), montmorillonite (84.75 mg g⁻¹), and organic resins.
In conclusion, walnut shell biochar presents a highly viable, eco-friendly, and economically sustainable solution for metolachlor remediation. By transforming agricultural waste into a high-performance adsorbent, it addresses both environmental contamination and resource inefficiency. This approach supports green water treatment strategies, particularly in rural and agricultural regions where herbicide pollution is prevalent. Future applications could extend to other organic pollutants, reinforcing the potential of biomass-based materials in global environmental protection.MedChemExpress (MCE) offers a wide range of high-quality research chemicals and biochemicals (novel life-science reagents, reference compounds and natural compounds) for scientific use. We have professionally experienced and friendly staff to meet your needs. We are a competent and trustworthy partner for your research and scientific projects.Related websites: https://www.medchemexpress.com