Influence of pH on the structural and magnetism stability of magnetic kaolinite composite

• Main Authors: Salleh, Nur Fatin Aqilah, Izman, Izzan Salwana, Johan, Mohd Rafie, Rusmin, Ruhaida
• Format: Conference Proceeding
• Language: English
• Subjects: Adsorbents; Adsorption; Aqueous solutions; Exposure; Impregnation; Iron oxides; Kaolinite; Magnetic properties; Magnetism; Magnetization; Magnetometers; Pollutants; Stability analysis; Structural stability; X ray powder diffraction
• ISSN: 0094-243X; 1551-7616
• DOI: 10.1063/5.0058214

Magnetic clay composite is one of the emerging nano-adsorbent developed for water pollutant removal in environmental clean-up studies. Yet, the efficiency of this adsorbent pertaining to its endurance against various aqueous solution condition is still inadequately assessed. This research aims to investigate the structural and magnetic stability of magnetic kaolinite composite (MKC) in aqueous solution under various pH. The MKC was prepared through solution method by impregnating co-precipitated iron oxide into kaolinite's gallery. The structural and magnetization change of synthesized MKC exposed in pH 2 (MKC-2) and pH 12 (MKC-12) were characterized using Powder x-ray diffraction (PXRD) and Vibrating Sample Magnetometer (VSM). MKC immersed in aqueous with neutral pH of 7 (MKC-7) acted as the control. The efficiency of MKC to remove Pb in solution was also evaluated. The PXRD result demonstrated that the structural characteristic of all MKC samples had insignificant alteration after exposure in either acidic or basic solution. The maneuver time for MKC-12 towards the external magnetic field was the slowest (79.3 ± 6.0 seconds). The magnetization strength of MKC is 14.9 emu/g while the MKC-12 and MKC-2 recorded value of 15.3 emu/g and 14.6 emu/g, respectively. At extreme aqueous condition (pH 2 with 0.1 M NaNO3), MKC recorded a maximum adsorption capacity of 1.73 mg/g (a 19% decrease from the adsorption without ionic strength) for Pb removal. Overall, MKC demonstrated a high structural stability and preserved its magnetism properties even after exposed in extreme pH solution. Hence, MKC has the potential to become a robust, economical, and advanced magnetic nano-adsorbent for future treatment of contaminated water.