Page 195 - AJWEP-22-4

Asian Journal of Water, Environment and Pollution. Vol. 22, No. 4 (2025), pp. 187-204.
doi: 10.36922/AJWEP025240191

ORIGINAL RESEARCH ARTICLE

Tailored Bombax ceiba-based activated carbons for
enhanced rhodamine B removal: A sustainable approach

to industrial effluent remediation

Dibyashree Shrestha*
Department of Chemistry, Institute of Science and Technology, Patan Multiple Campus, Tribhuvan University,
Lalitpur, Bagmati, Nepal
*Corresponding author: Dibyashree Shrestha (shresthadibyashree@gmail.com)

Received: June 9, 2025; 1st revised: July 1, 2025; 2nd revised: July 3, 2025; Accepted: July 7, 2025;
Published online: July 28, 2025

Abstract: Bombax ceiba wood waste-derived activated carbon (AC) provides a low-cost, sustainable, and
efficient solution for rhodamine B (RhB) dye removal from industrial wastewater through eco-friendly adsorption
techniques. This study reports the synthesis of ACs from B. ceiba wood dust using three different chemical
activating agents – phosphoric acid, potassium hydroxide, and sodium carbonate – followed by carbonization at an
optimized temperature determined through thermogravimetric (TG) analysis and differential scanning calorimetry.
The optimal carbonization temperature was identified as 400°C. AC samples were prepared through a one-step
chemical impregnation and carbonization process under nitrogen flow. Comprehensive characterization using
X-ray diffraction, Raman spectroscopy, Fourier-transform infrared spectroscopy, scanning electron microscopy,
and Brunauer–Emmett–Teller surface area analysis confirmed the formation of amorphous carbon structures
with abundant oxygenated surface functional groups and porous architectures. Among the three samples,
phosphoric acid-activated carbon (Bc-H) exhibited the highest surface area (1,451.2 m²/g) and a well-developed
micro–mesoporous structure. Batch adsorption experiments showed that Bc-H achieved 99.9% RhB removal under
optimized conditions (20 ppm initial dye concentration, pH 8.5, 0.03 g adsorbent, 10 min). Its superior performance
is attributed to its large surface area and rich surface functionalities. Notably, Bc-H also outperformed commercial
AC under identical conditions, demonstrating faster kinetics and higher removal efficiency. These findings
underscore B. ceiba wood dust as a low-cost and sustainable precursor for high-performance AC production. The
work contributes to waste biomass valorization and offers a scalable, eco-friendly solution for industrial wastewater
treatment, particularly relevant to textile and dyeing effluents in resource-limited settings such as Nepal.

Keywords: Bombax ceiba; Activated carbon; Rhodamine B adsorption; Wastewater treatment; Chemical activation;
Sustainable adsorbent

1. Introduction into aquatic ecosystems. Among these, rhodamine B
(RhB) – a xanthene-based cationic dye widely used
The growing demand for clean water, coupled in the textile, paper, plastic, and cosmetic industries
1
with the intensification of industrial activities, has – has attracted serious concern due to its high water
significantly increased the release of synthetic dyes solubility, photostability, and toxic persistence. RhB
2

Volume 22 Issue 4 (2025) 187 doi: 10.36922/AJWEP025240191