Competitive Adsorption of Methylene Blue and Methyl Orange on Modified Bentonite with Fe3O4
Yudi Aris Sulistiyo, Rizka Imroatul Mufidah, Riska Aprilia, Novita Andarini, Tanti Haryati, Suwardiyanto

Inorganic Material for Energy and Environment Research Group, Department of Chemistry, University of Jember, Jl. Kalimantan No. 37, Sumbersari, Jember, 68121

Abstract

Competitive adsorption of dyestuff mixture was studied to understand one on the solving problems of the coloring effluent. In this study, the adsorption process using methylene blue (MB) and methyl orange (MO) consecutively as a representation of cationic and anionic dyes using adsorbent modified geosorbent bentonite with Fe3O4. The crystal structure and a surface group of the adsorbent were evaluated by XRD, SEM, FTIR, and adsorption isotherm of N2. Besides, PHPZC exhibited the type of surface charge of the adsorbent in a different range of pH. In general, the adsorbent has a surface positive charge in acid pH conditions while a negative charge was in basic pH. Then, the adsorption processes were conducted in the single and binary batch system. The optimum adsorption condition of MB and MO were pH 6 and 4, respectively, in 100 mg/L of adsorbate concentration, 15 minutes of contact time, and 0.1 g of adsorbent dosage. The isothermal adsorption of both MB and MO followed Langmuir models with the maximum adsorption capacity consecutively 20.121 mg/g and 23.981 mg/g. The interesting finding was the adsorption capacity in the binary mixture was achieved nearly twice compared with single systems. It was indicated that possible interaction between both adsorbates before the adsorption process on the adsorbent. These phenomena were in line with the kinetic models of all adsorption processes following Pseudo Second Order models.

Keywords: Competitive Adsorption, Fe3O4-Bentonite, binary sistems of adsorption, Methylene Blue, and Methyl Orange

Topic: Materials Sciences: Synthetic and Characterization