Sintesis Silika Gel Terimobilisasi Ditizon dari Abu Dasar Batubara dan Aplikasinya untuk Adsorpsi Ion Logam Zn(II)
YASMEEN AFIFAH NURBAKHSY, Prof. Drs. Mudasir, M.Eng., Ph.D., Taufik Abdillah Natsir, S.Si., M.Sc., Ph.D.
2024 | Skripsi | KIMIA
Penelitian sintesis silika gel terimobilisasi ditizon
dari abu dasar batubara dan aplikasinya untuk adsorpsi ion logam Zn(II) telah dilakukan.
Penelitian ini bertujuan untuk mensintesis silika gel dari abu dasar batubara,
mengimobilisasi ditizon pada silika gel dan mengaplikasikan material tersebut
untuk adsorpsi ion logam Zn(II) dengan variasi pengaruh pH, massa adsorben,
waktu kontak, dan konsentrasi awal dari ion logam terhadap efektivitas
adsorpsi.
Penelitian diawali dengan preparasi dan aktivasi abu
dasar batubara. Abu dasar batubara yang telah teraktivasi digunakan untuk
proses sintesis silika gel. Silika gel yang dihasilkan diimobilisasi dengan
ditizon dalam medium NaOH. Karakterisasi terhadap material dilakkan
dengan Scanning Electrone Miscroscop (SEM),
Spektrofotometri Serapan Atom (AAS),
Spektroskopi Inframerah (FTIR), dan Difraksi Sinar-X
(XRD). Adsorpsi ion logam Zn(II)
dilakukan pada variasi
pH, massa adsorben, waktu kontak, dan konsentrasi awal larutan ion logam
Zn(II). Konsentrasi ion logam Zn(II) dalam larutan sebelum dan setelah adsorpsi
ditentukan menggunakan AAS.
Hasil karakterisasi menunjukkan bahwa sintesis silika gel dan immobilisasi ditizon pada permukaan silika gel telah berhasil dilakukan ditandai dengan adanya situs aktif berupa gugus siloksan, silanol, -SH, -NH, serta adanya mineral kuarsa dan ditizon. Kondisi optimum adsorpsi ion logam Zn(II) dengan silika gel dan silika gel terimobilisasi ditizon diperoleh pada pH 4, massa adsorben berturut-turut yaitu 0, 01 dan 0,02 g, waktu kontak 60 dan 30 menit, serta konsentrasi awal ion logam Zn(II) sebesar 80 mg L-1. Adsorpsi ion logam Zn(II) menggunakan silika gel dan silika gel terimobilisasi ditizon mengikuti model kinetika orde kedua semu dengan nilai konstanta laju berturut-turut yaitu 0,369 dan 0,186 g mg-1 min-1. Adsorpsi ion logam Zn(II) menggunakan silika gel dan silika gel terimobilisasi ditizon mengikuti model isoterm Langmuir dengan kapasitas adsorpsi (qm) yang dihasilkan berturut- turut sebesar 17,06 dan 40,98 mg g-1. Kapasitas adsorpsi ion logam Zn(II) dengan silika gel terimobilisasi ditizon yang lebih besar menunjukkan bahwa immobilisasi ditizon pada permukaan silika gel mampu meningkatkan kapasitas adsorpsi.
This study of synthesis of dithizone immobilised silica gel from bottom ash and its application to adsorption of
Zn(II) metal ions was aimed at synthesize and characterize silica gel from coal
bottom ash, to determine the effect of adsorbent weight, pH, contact time, and
concentration of metal ions on the adsorption of Zn(II) metal ions from silica.
coal bottom ash gel, tested the activity of dithizone- immobilized silica gel
from coal bottom ash on adsorption of Zn(II) metal.
This research was begun with the preparation of coal
bottom ash and its activation using HCl. The activated coal bottom ash (CBA) was used
for silica gel synthesis process. The resulting silica gel was used for ditizon
immobilization in NaOH medium. CBA before activation, after activation, and
silica gel were characterized by Scanning Electrone Microscop (SEM), Atomic
Absorption Spectrophotometry (AAS), Infrared Spectroscopy (FTIR), and X-ray
Diffraction (XRD). Dithzone-immobilized silica gel was characterized by SEM,
FTIR and XRD. Adsorption of Zn(II) metal ions was carried out at various pH,
adsorbent mass, contact time, and initial concentration of Zn(II) metal ion
solution. The concentration of Zn(II) metal ions in the solution was determined
using AAS.
The characterization results show that the synthesis of
silica gel and dithizone immobilization on the surface
of silica gel has been successfully obtained as indicated by the presence of
active sites of siloxane, silanol, -SH, -NH groups, as well as the presence of
quartz and dithizone minerals. The optimum conditions for the adsorption of
Zn(II) metal ions with silica gel before and after dithizone immobilization
were obtained at pH 4, adsorbent mass of 0.01 and 0.02 g, contact time of 60
and 30 minutes, and initial concentration of Zn(II) metal ions of 80 mg L-1. Adsorption of Zn(II) metal ions using
silica gel and ditizone-immobilized silica gel followed a pseudo
second-order kinetics model with rate constant values of
0.369 and 0.186 g mg-1 min-1, respectively. Adsorption of Zn(II) metal ions using silica gel and ditizone-immobilized silica gel followed the Langmuir isotherm model, possibly forms a single layer with the resulting adsorption capacity (qm) of 17.06 and 40.98 mg g-1 respectively. The greater adsorption capacity of Zn(II) metal ions with ditizon-immobilized silica gel indicates that the immobilization of ditizon on the silica gel surface has increased the adsorption capacity.
Kata Kunci : adsorpsi, abu dasar batubara, ditizon, silika gel
