Kinetic Modeling of Ni and Co Adsorption: A Comparative Study on Activated Zeolite

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ABSTRAK
Kehadiran logam berat seperti nikel (Ni) dan kobalt (Co) dalam air limbah berpotensi menyebabkan dampak lingkungan yang signifikan, sehingga diperlukan metode pengolahan yang efisien. Studi ini mengevaluasi kinetika adsorpsi Ni dan Co menggunakan zeolit alam yang diaktivasi secara termal melalui kalsinasi pada suhu 550°C. Proses adsorpsi dilakukan dengan variasi rasio massa adsorben dan dianalisis menggunakan beberapa model kinetika, yaitu Pseudo-First-Order (PFO), Pseudo-Second-Order (PSO), Intra-Particle Diffusion (IPD), dan Liquid Film Diffusion (LFD). Hasil penelitian menunjukkan bahwa proses adsorpsi Ni dan Co paling sesuai dengan model kinetika PSO, dengan koefisien determinasi (r²) lebih dari 0,99. Kapasitas adsorpsi kesetimbangan yang diperoleh mencapai 9,4877 mg g⁻¹ untuk Ni dan 7,3206 mg g⁻¹ untuk Co. Temuan ini menunjukkan bahwa proses adsorpsi dikendalikan oleh interaksi kimia melalui mekanisme pertukaran ion pada permukaan zeolit.

Kata kunci: Adsorpsi, Nikel, Kobalt, Zeolit

ABSTRACT
The presence of heavy metals such as nickel (Ni) and cobalt (Co), in wastewater poses significant environmental risks, necessitating the development of efficient treatment methods. This study investigates the adsorption kinetics of Ni and Co using natural zeolite thermally activated by calcination at 550°C. Adsorption experiments were conducted with varying adsorbent mass ratios and analysed using several kinetic models: Pseudo-First-Order (PFO), Pseudo-Second-Order (PSO), Intra-Particle Diffusion (IPD), and Liquid Film Diffusion (LFD). The results demonstrate that the adsorption of Ni and Co is best described by the PSO kinetic model, with a coefficient of determination (r²) exceeding 0.99. The equilibrium adsorption capacities achieved were 9.4877 mg g⁻¹ for Ni and 7.3206 mg g⁻¹ for Co. These findings suggest that adsorption is governed by chemical interactions via ion-exchange mechanisms at the zeolite surface.

Keywords: Adsorption, Nickel, Cobalt, Zeolite