Boron removal from solutions by talc clay

Abstract

In this study, boron uptake from solutions by raw and modified talc clay was investigated. The raw talc mineral was modified in aluminum chloride solution. Firstly, the pH experiments were carried out by raw and modified talc. Due to the relatively low adsorption capacity of the raw talc, the modified talc was used in further experiments. Boron adsorption experiments for the modified talc were conducted by different initial pH of the solution, temperature, boron concentration and adsorbent amount. Optimum parameters for the modified talc were determined as pH (7), concentration (500 mg/L), temperature (25°C) and adsorbent dosage (0.8 g/50 ml). The optimum pH was determined as 9 for raw talc use. Maximum boron adsorption capacities for the modified talc and raw talc were calculated as 3.10 and 2.4 mg/g, respectively. The thermodynamic parameters such as enthalpy, entropy and Gibbs free energy change were calculated, and the boron adsorption had exothermic nature. The optimization of boron adsorption data for the modified talc was performed by applying 23 factorial experimental design. The isotherm analysis data best fitted to the Langmuir model than the Freundlich model. The kinetic data fitted to the pseudo-second-order model rather than the pseudo-first-order model. Boron adsorption onto modified talc was controlled relatively by particle diffusion. Attenuated total reflection fourier-transform infrared spectroscopy analyses were performed for modified talc and boron adsorbed modified talc samples.