Synthesis of amorphous adsorbent derived from geothermal solid waste for methylene blue removal

Organic compounds like dyes and heavy metal ions are common pollutants in wastewater that have become a global problem. Adsorption has proven to be a successful technique in removing organic species such as methylene blue. Geothermal solid waste has the potential to be used as an adsorbent due to its silica content. Silica compound in the geothermal waste is the potential to be developed as porous material. Aluminum hydroxide and geothermal solid waste were added to the aqueous alkali (NaOH) in the continuous stirred tank reactor, then resulted an amorphous mesoporous material of the natrolite phase. The performance of the geoadsorbent was evaluated through the removal of various concentrations of methylene blue, and isotherm adsorption models evaluated the data. The adsorption mechanisms of the MB removal by geoadsorbent shown by FT-IR spectra are electrostatic attraction and hydrogen-bond formations. The geoadsorbent can remove methylene blue up to 84.449%, which the initial concentration of MB is highly dependent on adsorption. The Langmuir isotherm model provides the most accurate representation of methylene blue adsorption as a result of the physical process. with a correlation coefficient of 0.971.