Open Access

ARTICLE

Optimization of Phosphate Adsorption Using Activated Carbon Derived from Pangium edule Shell

by Rachmannu Ilham¹, Fataty Kurnia Rahmah¹, Nurul Faradilah Said², Mohamad Buang Budiono², Suprapto Suprapto^1,*

1 Chemistry Department, Faculty of Science and Analytical Data, Institut Teknologi Sepuluh Nopember Surabaya, Surabaya, 60111, Indonesia
2 Laboratory of Energy and Environment, Institut Teknologi Sepuluh Nopember Surabaya, Surabaya, 60111, Indonesia

* Corresponding Author: Suprapto Suprapto. Email:

Journal of Renewable Materials 2024, 12(11), 1895-1909. https://doi.org/10.32604/jrm.2024.055602

Received 02 July 2024; Accepted 03 September 2024; Issue published 22 November 2024

Abstract

This study investigated the efficiency of activated carbon from Pangium edule shells for removing phosphate from aqueous solution. The adsorption capacity of the synthesized activated carbon was determined to be 19.8392 mg g⁻¹. Various isotherm models were used to analyze the adsorption process, Henry, Freundlich, SIP, and Halsey isotherm fitting showed r² values close to 1.0. These isotherms indicated a combination of physisorption and chemisorption mechanisms, with heterogeneity and multilayer formation playing important roles. A pseudo-second-order model described the adsorption kinetics well, suggesting chemisorption as the dominant mechanism with an r² value of 1.0 and a rate constant k₂ of 1.2550 min⁻¹. The optimization was carried out using central composite design (CCD) using 3 factors (contact time (minutes), adsorbent dosage (mg), and initial phosphate concentration (ppm)) with 3 levels. The CCD output was analyzed using response surface methodology (RSM) to obtain the optimum level of each factor. A contact time of one to two hours and an adsorbent dosage of more than 80 mg was recommended. Optimal removal was achieved at initial phosphate concentrations between 800 and 1150 ppm. Morphological analysis using scanning electron microscope (SEM) showed a highly irregular surface structure of activated carbon, while X-ray Diffraction (XRD) patterns indicated the presence of amorphous carbon. Fourier Transform Infrared (FTIR) analysis identified functional groups contributing to the adsorption process and Energy Dispersive X-ray Spectroscopy (EDX) analysis confirmed the presence of phosphate on the carbon surface after adsorption. In conclusion, activated carbon from P. edule shells has significant potential in phosphate removal, with a combination of high adsorption capacity, effective adsorption mechanism, and favorable kinetics, making it a promising material for water treatment.

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