Moringa stenopetala bark: A novel green adsorbent for the removal of metal ions from industrial effluents

Publication date: Available online 8 August 2018Source: Physics and Chemistry of the Earth, Parts A/B/CAuthor(s): Temesgen Girma Kebede, Simiso Dube, Alemayehu Abebaw Mengistie, Thabo TI. Nkambule, Mathew Muzi NindiAbstractThis work demonstrates the potential of Moringa stenopetala bark powder as an adsorbent for the removal of heavy metals from wastewater. The bark powder was characterised using FTIR, XRD, zeta potential, TGA, SEM and BET techniques. Several processing parameters such as; contact time, adsorbent dose, concentration, pH, agitation speed and temperature were optimised. Using the optimum conditions the maximum removal efficiency of three heavy metals, Cd (II), Pb (II) and Cu (II) were99.08, 99.68 and 99.60% from synthetic wastewater respectively. When applied to industrial real wastewater the removal efficiency was 94.80, 95.50 and 94.23% for Cd (II), Pb (II) and Cu (II) respectively. The adsorption equilibria observed is in accordance to the Freundlich isotherm than the Langmuir isotherm. The maximum adsorption capacity of 38.46 ± 0.21, 35.71 ± 0.86 and 34.48 ± 0.93 mg g−1was observed for Cd (II), Pb (II) and Cu (II). The interaction of the cationic species with the bark powder was predominately via chemisorption rather than physisorption. The adsorption of the three metals ions,Cd (II), Pb (II) and Cu (II) was well defined by the pseudo-second order model (R2 = 1). The thermodynamic parameters such as ΔS, ΔH and ΔG were also determin...

Source: Physics and Chemistry of the Earth, Parts ABC - August 8, 2018 Category: Science Source Type: research