Magnetized algae-silica hybrid from porphyridium sp. Biomass with Fe 3 O 4 particle and its application as adsorbent for the removal of methylene blue from aqueous solution

Abstract

Algae-silica (AS) hybrid material from biomass Porphyridium sp. has been modified by coating Fe 3 O 4 particles (MPs) via a sol-gel process using tetraethyl orthosilicate to produce algae-silica-Fe 3 O 4 (AS-MPs). The AS-MPs produced were applied as adsorbent for the adsorption of methylene blue (MB). Identification of functional groups was performed by infrared spectrometer indicating that in AS-MPs there were active organic groups derived from Porphyridium sp., silanol and siloxane. Diffraction pattern of the AS-MP material analyzed by X-ray diffraction showed that the material has higher peak intensities at 2θ = 30.04° and 35.52°. Analyst results using a particle size analyzer showed that the average particle size distribution of the AS-MP material was 1.40 µm. In addition to the results of the analysis using scanning electron microscopy, material of AS-MPs has a more heterogeneous surface morphology. The models of MB adsorption by AS and AS-MP tend to follow the pseudo-second-order kinetic model and Freundlich adsorption isotherm. The adsorption of MB solution by AS-MP produces rate constants (k 2 ) of 0.003 g mg –1 min and adsorption capacity (q m ) of 96.927 mg g –1 under the experimental conditions of dose of adsorbent of 2.5 mg L –1 , interaction pH of 6, contact time of 60 min, and temperature of 27°C. The AS-MP material obtained from the results of this study can be used as an effective adsorbent because it can remove MB dyestuff in solution, it is chemically stable in acidic and neutral media, and it can be used repeatedly.