Preparation and Characterization of Adsorbent Materials from Taro (Colocasia esculenta) Plants for the Removal of Arsenic Ions from Contaminated Water

Abstract

Arsenic contamination in drinking water remains a critical global health issue, necessitating the development of effective and sustainable remediation technologies. This research investigates the preparation and characterization of adsorbent materials derived from Taro (Colocasia esculenta) plants for the removal of arsenic ions from contaminated water. Dried Colocasia Powder (DCP) was chemically activated and ground into a fine powder. The prepared biochar was subjected to comprehensive characterization using techniques such as X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), and methylene blue adsorption method. The FTIR analysis revealed the presence of functional groups such as hydroxyl, carboxyl, and alkene. The crystal planes of the XRD analysis are showed mostly amorphous nature of the adsorbents. The specific surface area values for ACR, ACS, and ACL were 448, 502, and, 478 m/g, respectively. With a high specific surface area, activated Colocasia stalk (ACS) was shown to be the best adsorbent among the three. The adsorption of As(III) was pH dependent and maximum at 7. The equilibrium time for adsorption of As(III) on ACS was less than 50 minutes. The adsorption data followed pseudo-second order kinetics with rate constant 0.01830 g/mg.min. The equilibrium adsorption capacity was determined from Langmuir model and was found to be 62.5 mg/g. Desorption and regeneration studies revealed that the biochar adsorbents retained significant reusability, maintaining over 85% of their initial arsenic removal efficiency after three cycles. Keywords: Biochar; Chemisorptions; Methylene Blue; Reflux; Taro.