Data for the synthesis, characterization, and use of xerogels as adsorbents

Xerogels were synthesized using the methodology proposed by Muehlemann et al. The xerogels M/R=0.5 were carbonized in a horizontal tubular furnace Carbolite model 12/65/550 under a N2 flow at 400, 450, and 550 °C for 2 h. The equilibrium adsorption experiments were carried out in a batch adsorber using 0.02 g of carbonized xerogel, 50 mL of fluoride, or bromide solution with different initial concentrations ranging from 10 to 100 mg L-1. The experiments were carried out at constant pH. The mass of fluoride or bromide adsorbed per gram of adsorbent (q), was obtained using a mass balance equation. The adsorption equilibrium data were fitted by Langmuir, Freundlich and Prausnitz-Radke isotherm models.The bromide and fluoride concentration in aqueous solution was measured by a potentiometric method with a bromide or fluoride ion-selective electrode.