Isotherm studies on removal of lead(II) ions from wastewater by magnetic carbon synthesised from Euphorbia hirta leaf extract

Abstract

In this article a magnetic carbon (MEHLC) has been synthesised from Euphorbia hirta leaf (EHL) extract to investigate the adsorption capacity of lead(II) ions from aqueous solutions and industrial wastewater. The prepared magnetic carbon (MEHLC) is compared with raw material (EHL) under the batch adsorption process such as contact time, pH, adsorbent dose and temperature. The adsorbents are characterized by FT-IR, SEM and EDX studies. The maximum removal is obtained at 300 K and the Langmuir isotherm of MEHLC and EHL is found to be with applicable q_m value of 385.86 and 21.96 mg g^-1, respectively. Various thermodynamic parameters, including the standard Gibbs free energy (∆G^o), standard enthalpy (∆H^o) and standard entropy (∆S^o), are evaluated. The MEHLC and EHL are tested with lead(II) plating wastewater through a batch mode process over five cycles; MEHLC showed better results than EHL.