Sintesis Komposit Asam Humat/Kitosan/Magnetit dan Aplikasinya sebagai Adsorben Zat Warna Malachite Green
NANDINA SALSABILLA PUTRI, Prof. Dr. Bambang Rusdiarso, DEA; Prof. Dr. Suyanta, M.Si.
2024 | Skripsi | KIMIA
Sintesis komposit asam humat/kitosan/magnetit (AHKM) sebagai adsorben zat warna malachite green telah dilakukan. Tujuan dari penelitian ini yaitu untuk sintesis asam humat yang dimodifikasi dengan kitosan dan magnetit guna menghasilkan adsorben dengan sifat magnetik, melakukan karakterisasi material, menentukan kondisi optimum adsorpsi, serta mempelajari kinerja adsorben. Penelitian diawali dengan ekstraksi asam humat dari tanah gambut berdasarkan kelarutan pada alkali dan asam. Komposit AHKM disintesis menggunakan metode kopresipitasi. Material komposit dikarakterisasi menggunakan FTIR, XRD, dan, VSM. Kajian adsorpsi malachite green pada adsorben dilakukan dengan variasi pH, waktu kontak, dan konsentrasi. Kinerja adsorben dipelajari melalui penentuan kinetika dan isoterm adsorpsi malachite green pada komposit AHKM.
Hasil karakterisasi FTIR menunjukkan gugus-gugus fungsional khas asam humat (-COOH dan -OH), kitosan (NH2), dan magnetit (Fe-O) pada komposit. Uji kristalinitas dengan XRD menunjukkan kesesuaian pola difraksi dari asam humat, kitosan, dan magnetit serta penurunan kristalinitas karena terjadinya interaksi antar material. Kurva histeresis dari VSM menunjukkan nilai saturasi magnetik yang menurun dari magnetit (50,79 emu g-1) ke komposit (12,88 emu g-1) karena penurunan kejenuhan partikel magnetit ketika dimodifikasi dengan material lain. Uji adsorpsi malachite green pada AHKM menghasilkan kondisi optimum adsorpsi pada pH 7, waktu kontak 120 menit, dan konsentrasi 180 ppm. Kinetika adsorpsi mengikuti model orde dua semu (Ho – McKay) dengan nilai kostanta laju adsorpsi sebesar 2,38 x 10-3 g mg-1 menit-1 dan r2 sebesar 0,9578. Isoterm adsorpsi mengikuti model Freundlich dengan nilai kapasitas adsorpsi sebesar 17,5 L g-1 dan R2 sebesar 0,9997.
Synthesis
of humic acid/chitosan/magnetite (AHKM) composite as an adsorbent for malachite
green dye has been conducted. The objectives of this study were to synthesize
modified humic acid with chitosan and magnetite to produce an adsorbent with
magnetic properties, characterize the material, determine optimum adsorption
conditions, and investigate the performance of the adsorbent. The research
began with the extraction of humic acid from peat soil based on solubility in
alkali and acid. The AHKM composite was synthesized using a co-precipitation
method. The composite material was characterized using FTIR, XRD, and VSM.
Adsorption studies of malachite green on the adsorbent were carried out by
varying pH, contact time, and concentration. The performance of the adsorbent
was studied by determining the kinetics and isotherms of malachite green
adsorption on the AHKM composite.
The FTIR characterization results showed the
presence of characteristic functional groups of humic acid (-COOH and -OH),
chitosan (NH2), and magnetite (Fe-O) in the composite. The XRD
crystallinity test showed the compatibility of the diffraction patterns of
humic acid, chitosan, and magnetite, as well as a decrease in crystallinity due
to the interaction between the materials. The hysteresis curve from VSM showed
a decrease in saturation magnetization from magnetite (50.79 emu g-1)
to the composite (12.88 emu g-1) due to a decrease in the saturation
of magnetite particles when modified with other materials. Adsorption tests of
malachite green on AHKM resulted in optimum adsorption conditions at pH 7,
contact time 120 minutes, and concentration 180 ppm. The adsorption kinetics
followed the pseudo-second order model (Ho – McKay) with an adsorption rate
constant value of 2.38 x 10-3 g mg-1 min-1 and
r2 of 0.9578. The adsorption isotherm followed the Freundlich model
with an adsorption capacity value of 17.5 L g-1
and R2 of 0.9997.
Kata Kunci : adsorpsi, asam humat, kitosan, magnetit, malachite green
