Characterization of Philippine natural bentonite

Abstract

Philippine natural bentonite is characterized using X-ray diffractometer (XRD), scanning electron microscope (SEM), chemical analysis, thermogravimetric-differential scanning calorimetry (TG-DSC), and Fourier transform infrared (FTIR) analysis. The cation exchange capacity (CEC) was also measured. XRD shows that the mineral is composed primarily of mordenite, hectorite, and montmorillonite. SEM shows the flaky and porous structure of the bentonite powder. Chemical analyses show that SiO2 (47.90 wt%) and Al2O3 (14.02 wt%) are the major components of the clay. TG-DSC shows that the mineral contains 15.55% moisture. IR transmittance spectrum shows the common vibration bands present in the sample which include O–H stretching of inter-porous water, symmetric and asymmetric stretching of hydroxyl functional groups, asymmetrical stretching of internal tetrahedra (O–Si–O and O–Al–O), symmetrical stretching of external linkages, and so on. The measured CEC were found to be 91.37 and 43.01 meq/100 g according to the ammonium acetate method and barium acetate method, respectively.

Adsorption of Heavy Metals from Small-Scale Gold Processing in Baguio Mining District, Philippines

“…The Philippine natural bentonite (PNB) is predominantly composed of mordenite, hectorite, and montmorillonite with kaolinite, feldspar, mica, and nontronite traces. It is chemically composed of 47.9% SiO 2 and 14.02% Al 2 O 3 (Olegario and Gili 2021). On the other hand, the Philippine natural zeolite (PNZ) comprised of mordenite followed by clinoptilolite and chabazite has a chemical composition of PNZ is 73.20% silica and 10.72% alumina, with a calculated Si/Al ratio of 3.67, which is higher than the Si/Al ratio of PNB (Olegario-Sanchez and Pelicano 2017).…”