The influence of polyethelene glycol concentration on silica xerogel synthesis from geothermal sludge to Pb(II) ions adsorption

Abstract

Abstract Geothermal solid waste contains around 80-95% of silica, which can be used for getting valuable materials. Synthetic silica can be produced from sodium silicate with polyethylene glycol (PEG) as a capping agent. The purpose of this research is to obtain silica xerogel from geothermal sludge, determine the effect of concentration variations of PEG to particle size and Si-OH/Si-O-Si groups ratio of silica xerogel on the adsorption ability to Pb (II) ions. The sol-gel method was applied to synthesize the product. The xerogel successfully resulted in deriving from geothermal solid waste with the addition of PEG. FTIR spectra indicated the presence of Si-OH stretching vibration at 954 cm−1 and Si-O-Si asymmetry stretching vibrations at 1089 cm−1. PSA data showed that silica gel with 0%, 2%, 4%, and 5% were 46.63; 197.01; 468.35; and 569.07 µm, respectively, and increase in particles size and the group’ ratio of Si-OH to Si-O-Si. The addition gel with a variation of PEG 2% slightly increased the Pb(II) ions adsorption capacity at various concentrations of 80 mg/L.