High surface area bamboo biochar production using a stainless-steel reactor enclosed with clay bricks

Abstract

Bamboo is a renewable and abundant agricultural resource with strong potential for producing high-value materials such as biochar. However, high volatile matter content and low BET surface area limit the biochar’s effectiveness in environmental applications. This study aims to enhance the properties of bamboo biochar using a stainless-steel reactor enclosed with clay brick, followed by methanol modification. Bamboo feedstock was cut, sun-dried, and carbonized at 900 °C for 5 hours to produce biochar, which was then treated with methanol to improve surface characteristics. Proximate analysis showed an increase in fixed carbon from raw bamboo to bamboo biochar and methanol-modified bamboo biochar from 12.65±0.69 to 57.13±0.78 and 58.88±0.43 wt.% respectively, and a decrease in volatile matter from 77.03±0.60 to 33.97±0.80 and 32.40±0.45 wt.% respectively. Ultimate analysis revealed an increase in carbon content from raw bamboo to bamboo biochar and methanol-modified bamboo biochar from 45.18±2.75 to 71.46±3.89 and 73.68±2.99 wt.% respectively and decreases in oxygen content after carbonization and methanol treatment. The BET surface area was observed with a significantly increase from 3.88±0.45 m²/g of raw bamboo to 256.75±39.80 m²/g of bamboo biochar and further increased to 343.84±2.14 m²/g in methanol bamboo biochar. Correspondingly, the pore volume of raw bamboo to methanol-modified bamboo biochar increases from 0.001±0.001 to 0.17±0.02 cm³/g and pore diameter decreases from 2.07±1.88 to 1.86±0.06 nm respectively. SEM images illustrated the development of relatively smooth surface and well-developed porous structure compared to raw bamboo surface. FTIR analysis indicates that the presence of functional groups (C–O, O–H, C–C) which confirms that changes in chemical and structural modification after carbonization and methanol modification. These results indicate that slow carbonization process with methanol modification significantly enhances the physiochemical characteristics of bamboo biochar and makes it a strong potential adsorbent for environmental pollutant removal.