ADSORPSI FENOL DAN p-KLOROFENOL PADA Fe3O4 TERSALUT ASAM HUMAT (AH-Fe3O4)

SOERJA KOESNARPADI, Prof. Drs. Sri Juari Santosa, M.Eng, Ph.D, Drs. Dwi Siswanta, M.Eng, Ph.D, Prof. Dr. Bambang Rusdiarso, DEA

2017 | Disertasi | S3 Kimia

Sintesis nanopartikel Fe3O4 tersalut asam humat (AH-Fe3O4) telah berhasil dilakukan dan diaplikasikan untuk adsorpsi fenol dan p-klorofenol dalam larutan. Sintesis dilakukan dengan metode kopresipitasi kimia dalam kondisi basa menggunakan ammonium hidroksida dan penambahan AH dengan perbandingan massa AH dan Fe3O4 = 1:20, 2:20, 4:20 dan 6:20. Asam humat diperoleh dari tanah gambut daerah Sambutan, Kalimantan Timur, Indonesia yang diekstraksi menggunakan larutan basa NaOH 0,1 N. Karakterisasi adsorben dilakukan dengan menggunakan Fourier transform infrared (FTIR), X-ray diffraction (XRD), Scanning electron microscope (SEM), Vibrating sample magnetometer (VSM), Transmission electron microscope (TEM) dan model Brunauer-Emmett-Teller (BET). Teknik batch digunakan dalam adsorpsi fenol dan p-klorofenol dengan mempelajari pengaruh pH, waktu kontak dan konsentrasi optimum serta menentukan model kinetika adsorpsi dan model isoterm adsorpsi. Hasil karakterisasi menunjukkan bahwa Fe3O4 tersalut AH tidak mengubah struktur kristal Fe3O4 namun menghasilkan intensitas puncak dan sifat kemagnetan lebih rendah dibanding Fe3O4. Foto SEM menunjukkan bahwa ukuran partikel magnetik relatif homogen sekitar 10-18 nm. Kestabilan ion Fe pada AH-Fe3O4 terjadi pada pH 3-11 sedangkan kestabilan AH pada AH-Fe3O4 terjadi pada pH 1�11. Hasil kajian adsorpsi fenol oleh Fe3O4 optimum pada pH 5 sedangkan pada AH-Fe3O4 optimum pada pH 5 dan 6. Adsorpsi p-klorofenol oleh Fe3O4 optimum pada pH 5 sedangkan pada AH-Fe3O4 optimum pada pH 3. Model kinetika adsorpsi fenol dan p-klorofenol pada Fe3O4 dan AH-Fe3O4 dapat dijelaskan dengan persamaan model kinetika adsorpsi pseudo-order dua. Model isoterm adsorpsi fenol dan p-klorofenol pada Fe3O4 dan AH-Fe3O4 sesuai dengan model isoterm Langmuir.

The coating of Fe3O4 nanoparticles using humic acid (HA) to form HA-Fe3O4 has been successfully done and applied for phenol and p-chlorophenol sorption in aqueous solution. The synthesis was prepared using coprecipitation method in an alkaline condition using ammonium hydroxide and the addition of HA with mass ratios of HA and Fe3O4 = 1:20, 2:20, 4:20, 6:20. The HA was taken from peat soil in Sambutan Village, East Kalimantan, Indonesia and was extracted in NaOH 0.1 M solution. The adsorbent was characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), Scanning electron microscope (SEM), Vibrating sample magnetometer (VSM), Transmission electron microscope (TEM) and Brunauer-Emmett-Teller (BET) model. The batch technique was conducted for phenol and p-chlorophenol sorption to investigatie the the effect of pH, contact time and optimum concentration. Kinetics and the isotherm model were also determinated. Characterization result showed that the coating of HA on the surface of Fe3O4 did not change the crystal structure of Fe3O4, had lower peak intensities and saturation magnetization than Fe3O4 if added with HA. The SEM image indicated the magnetic particle size was almost homogenous by 10-18 nm. Iron and HA in HA-Fe3O4 materials synthesized using different mass ratios were stable in pH range of 3-11 and 1�11, respectively. The results of adsorption experiment demonstrated that phenol adsorption on Fe3O4 was optimum at pH 5.0 and on HA-Fe3O4 were optimum at pH 5-6. Adsorption of p-chlorophenol on Fe3O4 was optimum at pH 5 and on HA-Fe3O4 materials were optimum at pH 3. The kinetics model for phenol and p-chlorophenol adsorption on Fe3O4 and HA-Fe3O4 could be described using pseudo-second order kinetic equation. The isotherm model for phenol and p-chlorophenol adsorption on Fe3O4 and HA-Fe3O4 in accordance with the Langmuir isotherm model.

Kata Kunci : adsorpsi, fenol, p-klorofenol, isoterm, kinetika, AH-Fe3O4