Optimization of phosphorus adsorption on honeycomb briquette ash by application of response surface methodology

Honeycomb coal ash was selected as phosphorus adsorbent to explore the influence of different factors on phosphorus adsorption performance for phosphorus containing wastewater. The structural, physical and chemical properties of coal ash were determined by SEM, BET and XRF analysis methods. The response surface methodology (RSM) was applied for experimental design of phosphorus adsorbent. The effect of five independent variables including initial concentration of phosphorus, coal ash dosage, coal ash particle size, adsorption time and pH on the phosphorus removal efficiency (R (%)) was studied in the ranges of 5-7 mg/L, 6-10 g, 180-220 mesh, 20-30 min and 6.12-6.92 respectively. 46 runs of experiments were designed by the Design-Expert software. The optimum conditions for initial concentration of phosphorus, coal ash dosage, coal ash particle size, adsorption time and pH were found as 6.34 mg/L, 8.17 g, 207.97 mesh, 23.33 min and 6.64, respectively. At these conditions, removal efficiency and desirability function were found to be 96% and 1.000, respectively. The results of kinetic model reveals that the adsorption process conforms to Pseudo-first-order kinetics Equation (R2 =0.9991). The briquette ash has a good application prospect for the actual treatment of phosphorus containing wastewater, which provides a certain treatment strategy for the restoration of damaged water environment.