Adsorpsi Anilin oleh Karbon Aktif Magnetik Cangkang Kelapa Sawit
Authors: Alfiyani Hani , Nurlina Nurlina , Wahyuni Nelly 
Published: September 2022

<p>Karbon aktif merupakan salah satu adsorben yang dapat dikompositkan dengan besi oksida menjadi karbon aktif magnetik (KAM) sehingga mempermudah proses pemisahannya dari dalam larutan. Penelitian ini menjelaskan kinerja KAM dalam mengadsorpsi anilin dengan menentukan isoterm dan kinetika adsorpsinya serta efektifitas sifat magnet dalam pemisahan KAM. Karbon aktif magnetik dibuat dari cangkang kelapa sawit dikarbonisasi (300 ºC, 2 jam), diaktivasi fisika (600 ºC, 30 menit), dan dilanjutkan aktivasi kimia (ZnCl<sub>2</sub> 0,05 M). Karbon aktif magnetik dibuat dengan mencampurkan karbon aktif dan larutan Fe(III)/Fe(II) (rasio mol 2:1). Pengukuran daya serap adsorpsi menggunakan variasi konsentrasi anilin (25, 50, 75, 100, dan 125 ppm) dan waktu kontak (60, 120, 180, 240, dan 300 menit). Adsorben KAM dikarakterisasi menggunakan spektrofotometer infra merah (FTIR), difraktometer sinar-X (XRD), fluoresensi sinar-X (XRF), <em>Surface Area Analysis </em>(SAA) dan konsentrasi anilin diukur dengan spektrofotometer UV-Vis. Hasil analisis FTIR menunjukkan munculnya serapan Fe-O pada bilangan gelombang 580,32 cm<sup>-1 </sup>yang mengindikasikan adanya besi oksida pada KAM. Difraktogram XRD menunjukkan puncak pada 2θ 18,39º; 34,09º; 34,82º; 35,03º; dan 35,87º dari magnetit Fe<sub>3</sub>O<sub>4</sub>, puncak 2θ 32,83º; 35,77º; dan 38,18º dari hematit. Hasil SAA menunjukkan luas permukaan KAM 179,40 m<sup>2</sup>/g, diameter rata-rata pori 24,95 Å dan XRF menunjukkan adanya kandungan Fe<sub>2</sub>O<sub>3 </sub>pada KAMsebesar 76,316%. Kapasitas adsorpsi optimum diperoleh pada konsentrasi anilin 100 ppm dengan waktu kontak selama 240 menit sebesar 86,254 mg/g. Kinetika adsorpsi sesuai dengan model pseudo-orde dua (R<sup>2</sup> sebesar 0,9934) dengan konstanta kinetika 0,0073 g/(mg.menit).</p><p><strong>Aniline Adsorption by Oil Palm Shell Magnetic Activated Carbon. </strong>Activated carbon is one of the adsorbents that can be composted with iron oxide into magnetic activated carbon (KAM), making it easier to separate from the waste solution. This research investigated the KAM's performance in absorbing aniline by determining its adsorption isotherms and kinetics as well as the effectiveness of magnetic properties in KAM separation. Magnetic activated carbon was produced by oil palm shells carbonization at (300 ºC, 2 hours), followed by physical activation (600 ºC, 30 minutes), and continued by chemical activation (ZnCl<sub>2</sub> 0.05 M). Magnetic activated carbon was made by mixing activated carbon and Fe(III)/Fe(II) solution (mole ratio 2:1). Adsorption measurements use variations in aniline concentrations (25, 50, 75, 100, and 125 ppm) and contact times (60, 120, 180, 240, and 300 minutes). KAM adsorbents were characterized using infrared spectrophotometers (FTIR), X-ray diffractometers (XRD), X-ray fluorescence (XRF), and surface area analysis (SAA). Meanwhile, the adsorbed aniline concentrations were measured by UV-Vis spectrophotometers. The results of the FTIR analysis showed the appearance of Fe–O absorption in wavenumbers 580.32 cm<sup>-1</sup> indicating the presence of iron oxide in KAM. XRD diffractogram shows peaks at 2θ 18.39º; 34.09º; 34.82º; 35.03º; and 35.87º of Fe<sub>3</sub>O<sub>4</sub> magnetite, and peaks 2θ 32.83º; 35.77º; and 38.18º from hematite. SAA results showed a surface area of KAM of 179.40 m<sup>2</sup>/g and an average pore diameter of 24.95 Å. XRF showed the presence of Fe<sub>2</sub>O<sub>3</sub> content in KAM of 76.316%. An optimum adsorption capacity of 86.254 mg/g was obtained at an aniline concentration of 100 ppm with a contact time of 240 minutes. Adsorption kinetics correspond to the second-order pseudo-model (R<sup>2</sup> of 0.9934) with a kinetic constant of 0.0073 g/(mg.min).</p>