Experimental and modeling studies on the removal of bromocresol green from aqueous solutions by using pine cone-derived activated biochar

Abstract

This study was carried out to evaluate the potential application of pine cone (PC)-derived activated biochar which has a surface area of 1714.5 m2/g for bromocresol green (BCG) dye removal from aqueous solution. Batch adsorption experiments involved varying pH, temperature, contact time, adsorbent dosage, and initial dye concentrations and the maximum BCG removal (96.27%) occurred at pH: 2.0, T: 45 °C, m: 2 g/L, t: 15 min., and Co: 25 mg/L. To study the characteristics of adsorption, the adsorption kinetic isotherm and thermodynamic parameters were employed. The experimental data was evaluated to fit well with the Temkin isotherm (R2 = 0.99) and the adsorption process followed pseudo-first-order kinetics (R2 = 0.96). Thermodynamic parameters obtained from the adsorptive uptake showed that the interaction was endothermic and spontaneous in nature. The regenerated activated PC biochar showed good performance (95.0%), even, after 4th regeneration. To predict the BCG adsorption capacity of activated PC biochar, many different artificial neural network (ANN) models have been developed. The optimal ANN model gave mean absolute error (MAE), mean bias error (MBE), root mean square error (RMSE), and R2 values of 0.036, 0.578, 0.947, and 0.999, respectively. The results obtained showed that ANN can be used to effectively model the BCG adsorption process.