Characterization of KCl-Activated Carbon Derived from Walnut Shells of Tidore Island, Indonesia

Abstract

Activated carbon is highly valued for its versatility and extensive industrial use. Walnut (Canarium vulgare Leech), an indigenous Indonesian plant primarily found in Eastern regions like Maluku and Tidore islands, produces shells that can be converted into activated carbon. This study involved obtaining carbon from walnut shells through pyrolysis at 360°C for 6 hours, followed by activation in a 3M KCl solution for 24 hours. The activated carbon was analyzed using Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy-Energy Dispersive X-ray (SEM-EDX), and X-ray Diffraction (XRD). FTIR analysis revealed functional groups including N-H, Ar-H (aromatic), C≡N, carbonyl CO, and ester CO. SEM images showed a non-homogeneous structure in pyrolyzed and KCl-activated carbon. After activation, the pore diameter distribution increased significantly from 496.2 nm to 1,226 µm. EDX analysis indicated a rise in carbon content from 85.40% after pyrolysis to 86.50% post-KCl activation. XRD diffractograms suggested amorphous structures in both forms of carbon, as indicated by loose peaks and broad diffraction patterns. This research introduces the novel use of KCl as an activator to enhance the porosity of walnut shell-derived activated carbon. The KCl-activated carbon demonstrated an ability to remove 0.122 mg/L of Fe(III), achieving 16.78% Fe(III) absorption in 150 minutes. These findings suggest that KCl-activated walnut shell carbon could be an effective alternative absorbent for clean water treatment in the future.

Received 15/01/2024

Revised 27/09/2024

Accepted 29/09/2024

Published Online First 20/12/2024