Fig. 2: Effect of time and pH on the adsorption of phosphate.

a Effect of time on the adsorption of phosphate with condition: 5 g (HIAO/225H)/L, 20 mg P L−1, pH 6.0, room temperature of ∼30 °C). b Effect of pH on the adsorption of phosphate with condition: 50 h, 5 g (HIAO/225H)/L, 20 mg P L−1, and room temperature of ∼30 °C; and experimental condition (n = 3 ±standard deviation [s.d.]).