Synthesis and Characterization of MnFe2O4 Spinel as a Fenton-Like Heterogeneous Catalyst for the Degradation of Rhodamin B Lina Mahardiani (a*), Mustika Della Asti (a), Endang Susilowati (a), Yulianto Agung Rezeki (a), Sulistyo Saputro (a)
(a) Chemistry Education, Universitas Sebelas Maret, Surakarta, Central Java 57126 Indonesia
*mahardiani.lina[at]staff.uns.ac.id
Abstract
This research aims to (1) Understanding how to synthesize Fe2O3 and MnFe2O4 materials. (2) Analyzing the characteristics of Fe2O3 and MnFe2O4 materials. (3) Analyzing the effectiveness of MnFe2O4 as a heterogeneous Fenton-like catalyst for the degradation of Rhodamine B dye. (4) Determining the degradation kinetics model of a Fenton-like system using MnFe2O4 for Rhodamine B. The study was conducted using a laboratory experimental method. The results of the study showed that: (1) Fe2O3 and MnFe2O4 , was successfully synthesized- the resulting compounds were reddish-brown and blackish-brown, respectively, were in powder form and can be attracted by magnets. FTIR characterization revealed two main peaks characteristic of Fe-O or O-Fe-O stretching vibrations in Fe2O3 and Mn-O and Fe-O in MnFe2O4 at tetrahedral and octahedral sites. The XRD patterns of Fe2O3 and MnFe2O4 correspond to the JCPDS standard patterns with main peaks at 2theta = 33,10 degrees (104) and 2theta = 33,14 degrees (311), respectively. SEM results of MnFe2O4 reveal surface morphology consisting of particles ranging from spherical to irregular shapes with varying sizes, and the presence of Mn, Fe, and O elements was identified. The surface area of MnFe2O4 was determined to be 6,674 m2/g via BET analysis and indicates the presence of hysteresis, which proves that the MnFe2O4 structure exhibits dominant mesoporous characteristics. (3) MnFe2O4 functions optimally as a catalyst under the following conditions: 25 mL of 9,8 M H2O2, 0,1 g of catalyst, a Rhodamine B concentration of 5 ppm, and a contact time of 60 minutes, achieving a degradation percentage of 73,99%. A concentration of 10 ppm was selected as the midpoint for further research on regeneration, yielding an increasing degradation percentage over 4 regeneration cycles, reaching 98,43%. (4) The degradation kinetics of MnFe2O4 in a Fenton-like system toward Rhodamine B follow pseudo first order kinetics with an R2 value of 0,9809.
Keywords: Catalyst, MnFe2O4, Fenton-like, Rhodamine B
