Treatment of Pb ion contaminated wastewater using hazardous parthenium (P. hysterophorus L.) weed

In this study, a low-cost, sustainable biosorbent parthenium (P. hysterophorus L.) weed powder was investigated for the treatment of Pb contaminated wastewater. Physicochemical characteristics of the biosorbent were measured, namely, bulk density as 0.42 g cm^-3, porosity as 45%, BET surface area as 20.79 m² g^-1, particle size as <125 μm, moisture content as 68% and point of zero charge as 5.6. The various parameters of biosorption process were examined. The maximum percentage removal of Pb ion achieved was 98.3% with 1.0 g L^-1 of biosorbent dose for 50 mg L^-1 initial Pb ion concentration at process condition of pH 4, temperature 30 °C (303 K), agitation speed 200 rpm and 150 min of equilibrium contact time. The equilibrium data were examined by various rate kinetics models and adsorption isotherm models. Sorption of Pb ion onto biosorbent was confirmed by Fourier transform infrared spectroscopy (FTIR) transmittance spectra and field-emission scanning electron microscopy and energy-dispersive X-ray (FESEM-EDX) analysis of native as well as Pb ion adsorbed biosorbent. The change in thermodynamic parameters, such as Gibbs free energy (ΔG), enthalpy (ΔH) and entropy (ΔS) was calculated. The results suggest that biosorption process using parthenium (P. hysterophorus L.) weed powder as biosorbent was a spontaneous, feasible and efficient method for treatment of Pb-bearing wastewater.