Rattan waste turned into high-performance microreactor for water purification

In a significant advancement for sustainable water treatment, researchers from China have developed a high-flux biochar microreactor derived from rattan, a fast-growing and underutilized biomass. The study, published in the Journal of Bioresources and Bioproducts, demonstrates how structural engineering of biochar through component regulation can dramatically enhance its catalytic performance in advanced oxidation processes (AOPs).
The team, led by corresponding authors Lei Shi and Jianxiong Lyu, focused on modulating the intrinsic cellulose and lignin content of rattan to tailor the pore structure, surface area, and electronic properties of the resulting biochar. By selectively removing lignin through controlled delignification, they created a hierarchically porous carbon framework rich in boundary-like defects and graphitic domains—key features for efficient electron transfer and peroxymonosulfate (PMS) activation.
Unlike traditional batch reactors that require energy-intensive stirring and catalyst recovery, this microreactor operates under gravity-driven flow, achieving an ultrahigh flux of 2.3×10⁴ L/(m²·h). In continuous-flow experiments, the system achieved complete degradation of tetracycline, methylene blue, and rhodamine B—common pollutants in pharmaceutical and textile wastewater.
Mechanistic investigations revealed that the biochar primarily activates PMS through a non-radical pathway, dominated by singlet oxygen (¹O₂) and direct electron transfer. Electron paramagnetic resonance (EPR) spectroscopy and electrochemical analyses confirmed the absence of hydroxyl or sulfate radicals, indicating a safer and more selective oxidation process. The boundary-like defects in the carbon structure were identified as the primary active sites for ¹O₂ generation, while the biochar’s electrical conductivity facilitated direct redox reactions between pollutants and PMS.
The optimal performance was observed in a sample delignified for 6 hours (PRBC-6h), which had a cellulose-to-lignin ratio of approximately 4.46. This sample exhibited the highest surface area (501.6 m²/g), the lowest charge-transfer resistance, and the most favorable defect configuration. Even after five reuse cycles, the microreactor retained over 70% of its original efficiency, and regeneration at 400°C restored nearly full activity.
The study also highlighted the system’s robustness in real-world conditions. Tests in tap and river water showed minimal performance loss, and the presence of common interferents like chloride, bicarbonate, and humic acid had little to no inhibitory effect. These results underscore the microreactor’s potential for practical deployment in natural water matrices.
This work not only offers a scalable and low-cost solution for wastewater treatment but also opens new avenues for valorizing agroforestry waste. The component-regulation strategy could be extended to other lignocellulosic biomass, such as wood or coconut shells, to create tailored biochar catalysts for various environmental and energy applications.

See the article:

DOI

https://doi.org/10.1016/j.jobab.2025.10.003

Original Source URL

https://www.sciencedirect.com/science/article/pii/S2369969825000684

Journal

Journal of Bioresources and Bioproducts