Sequestration of Ni(II) and Zn(II) Ions from Electroplating Wastewater Using Biogenic Manganese Oxides

A harmonious experimental–gauge approach was used to examine the ability of biogenic manganese oxide, formed in the cultures of a Mn(II) oxidizing bacteria, Mn 21 to sequester Ni(II) and Zn(II) ions. Batch experiments were carried out in order to model and optimize the biosorption process. The influence of four parameters i.e. pH, biosorbent dosage, contact time and temperature on the uptake of Ni(II) and Zn(II) ions was determined using a response surface methodology (RSM). The Mn 21 exhibited the highest 96.8% and 92.1% Ni(II) and Zn(II) removal respectively at an initial pH of 7.0, biosorbent dosage 0.775 g/L, Contact Time 42 hrs and temperature 32°C. The biosorption mechanism was also investigated using Fourier transfer infrared (FT-IR) analysis of untreated, Ni(II) and Zn(II) ions loaded Mn 21 biomass. The biosorbent was characterized by Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS). It was found that the newly formed biogenic manganese oxides (BMO) effectively sequestered Ni(II) and Zn(II) ions from electroplating wastewater.