Modeling and Optimization of Cadmium and Lead Adsorption onto Natural Pterocarpus santalinoides Fruit

The presence of heavy metals in wastewater has raised concern in developing countries because of their impact on human health and environmental ecology. Therefore, this study aims to remove cadmium and lead ions from wastewater using natural Pterocarpus santalinoides fruit through the adsorption method. The Box-Behnken design (BBD) of the response surface methodology (RSM) method was adopted to optimize the process variables such as contact time (20-100 min), adsorbent dose (0.1-0.5 g), initial metal ion concentration (10-50 mg/l), and temperature (30-70 °C). The ANOVA results clearly indicate that the linear model was not sufficient to best predict the removal performance of cadmium (R2 = 0.4009) and lead (R2 = 6353). The optimum conditions for the maximum Cd (94.81%) and Pb (89.23 %) adsorption onto the adsorbent were achieved at contact time (42.16 min), adsorbent dose (0.25 g), initial metal ion concentration (21.52 mg/l), and temperature (37.00 °C). According to the findings of the present work, Pterocarpus santalinoides shows to be a potential eco-friendly and cheap adsorbent for the removal of Cd and Pb from aqueous solutions. The BBD-RSM actual and predicted values of the Cd and Pb ions response show non-significant correlation, suggesting poor agreement between the two, revealing that the BBD-RSM model applied is not effective for the relationship between the four parameters examined in the Cd and Pb ions removal process.