ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Adsorption and desorption kinetics of lead from aqueous solutions by biosorbents

Mohanapriya Ganesan and Chitdeshwari Thiyagarajan

Department of Soil Science and Agricultural Chemistry, Directorate of Natural Resource Management, Tamil Nadu Agricultural University, Coimbatore, India

E-mail: gmohanapriya97@gmail.com

Received: 17 July 2023  Accepted: 3 October 2023

Abstract:

Removal of lead (Pb) by sorbents through adsorption is one of the effective methods to remediate contaminated aquatic systems. This study assesses the lead removal potentials of various cost-effective, readily available biosorbents such as, coirpith, cocopeat and poultry manure from waste water in a batch incubation experiment. The biosorbents were characterised and the effect of sorbent dosage, Pb²⁺ concentration at different time intervals on Pb sorption was studied and the data were fitted to various kinetic models to understand the mechanism of adsorption. The FTIR peaks revealed the involvement of hydroxyl and carboxylic groups in Pb sorption and SEM micrographs shows highly porous surface of poultry manure that enhances Pb sorption. Higher Pb adsorption (71.2%) rate was observed in poultry manure than coirpith (40.4%) and cocopeat (47.6%) which increased with increasing sorbent dosage (62.6 to 79.3%) and time intervals (0 to 78.9%). Kinetic modelling of sorption data revealed that pseudo second-order kinetic model best explained the adsorption by cocopeat (R² = 0.96 to 0.99) and poultry manure (R² = 0.97 to 1.00) while zero-order kinetics model described it better for coirpith (R² = 0.99 to 1.00). Chemisorption was the dominant mechanism operating in cocopeat and poultry manure; while, surface sorption was dominant in coirpith. On the other hand, least desorption was found in poultry manure (0.75%) than coirpith (19.0%) and cocopeat (1.58%) which decreased with increasing sorbent dosage at successive time intervals. Hence, it could be concluded that, poultry manure is the effective sorbent that can be utilised for the removal of Pb from wastewater.

Keywords: Lead; Biosorbents; Adsorption; Desorption; Kinetic models

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-023-03136-0

Chemical Papers 78 (2) 993–1008 (2024)