# Application of an Electrochemical Sensor Based on Nitrogen-Doped Biochar Loaded with Ruthenium Oxide for Heavy Metal Detection

## TL;DR

Researchers created a sensor from cotton waste to detect heavy metals, offering an eco-friendly and cost-effective solution.

## Contribution

The novel use of nitrogen-doped biochar loaded with ruthenium oxide for heavy metal detection is introduced.

## Key findings

- The sensor accurately quantifies lead and copper ions with high sensitivity and wide linear range.
- The sensor demonstrated commendable accuracy when tested on plant samples from Xinjiang, China.

## Abstract

Cotton is a widely cultivated cash crop and represents one of the most significant raw materials for textiles on a global scale. The rapid development of the cotton industry has resulted in the production of substantial amounts of cotton husks, which are frequently underutilized or discarded. This study utilizes agricultural waste, specifically cotton shells, as a precursor for biochar, which is subsequently carbonized and nitrogen-doped with ruthenium oxide to synthesize an innovative composite material known as RuO2-NC. An electrochemical sensor was developed using this composite material to detect heavy metals, particularly lead and copper ions. The results demonstrate that the electrochemical sensor can accurately quantify concentrations of lead and copper ions across a wide linear range, exhibiting exceptional sensitivity. Furthermore, the sensor was tested on samples from Viola tianshanica Maxim (Violaceae) collected from the Xinjiang Uygur Autonomous Region (XUAR) in China, showing commendable accuracy and sensitivity. This approach promotes eco-friendly recycling of agricultural waste while offering advantages such as straightforward operation and reduced costs, thereby presenting promising prospects for practical applications.