Chapter 22 - Synthesis of novel nanobioadsorbent for the effective removal of Pb2 + and Zn2 + ions—Adsorption, equilibrium, modeling, and optimization studies

Abstract

The aim of the present study involves the optimization of Pb2+ and Zn2+ ions by using aquatic weed Eichhornia crassipes (EC) and Lemna minor (LM). The characterization of nano-adsorbent was done using Scanning Electron Microscopy (SEM), Energy Dispersive X-ray (EDX), and Fourier Transform Infrared Spectroscopy (FTIR) studies. Batch adsorption studies were carried out for different process parameters such as pH (2−10), adsorbent dosage (1–3g/L), initial concentration (10–50mg/L), and contact time (24–120 h). The fundamental process variables were optimized using Response Surface Methodology (RSM) based on Central Composite Design (CCD). The Analysis of Variance (ANOVA) data obtained from the RSM studies was analyzed using a second-degree polynomial equation and the study of the determination of 3D plot showed the interaction among the variables in the adsorption system. Adsorption isotherm ensured well with the Langmuir model. The maximum monolayer adsorption capacity of Pb2+ and Zn2+ions was found to be 35.71mg/g(EC), 38.46mg/g(EC), 28.5mg/g(LM), and 26.31mg/g(LM), respectively. Kinetic studies that fit well with pseudo-second order show good agreement between experimental and predicted results. The experimental values reported that the adsorbent material can be effectively utilized as a cheap material for the adsorption of Pb2+ and Zn2+ metal ions from the battery effluent.