(253c) Developing Nanometal Oxide Composite from Solid Waste to Make an Efficient Adsorbent for Heavy Metal Removal

Over the last few decades, there is a generous rise in use of heavy metals in different human and industrial activities. Unlike organic pollutants heavy metals are not biodegradable and they easily get accumulated in living tissues and become concentrated in food chain. Among those heavy metals, Ni(II) and its compounds are being widely used in many industries such as, electroplating, surface treatment and metal finishing facilities. Nickel is suspected to cause lung, nose and bone cancer moreover, it leads to extreme weakness, dermatitis, headache, dizziness, respiratory distress, chest pain, shortage of brain and dry cough. The toxic nature of crops, algae and fishes are also reported. Keeping the harmful effects of Ni(II) in mind, more research attention needs to be paid for finding an efficient and cost effective method for removing the said compound from waste water.

In this aspect, a number of methods including ion exchange, chemical precipitation, coagulation, flocculation, membrane separation, electro dialysis, electro chemical treatment and biological treatment are there. However, they have many disadvantages (like high energy and cost consumption, complex in operation, incomplete removal and production of huge solid sludge). Due to all these factors adsorption has drawn attention for the separation of heavy metals from aqueous solution. Selection of a suitable adsorbent is a critical issue for the adsorption process.

This work explores the feasibility of alumina based nanocomposite in removing heavy metal ions (Ni(II)) from waste water. The nanocomposite is made from the alumina extracted from scrap aluminium with a suitable nanometal oxide (i.e., ZnO) introduced in it, to enhance its adsorption capacity. The prepared adsorbent is characterised by Scanning Electron Microscopy (SEM), Brunauer–Emmett–Teller (BET) analysis and X-ray Diffraction (XRD) analysis in order to observe the surface morphology and crystalline nature. The adsorption quality is studied for Ni(II) adsorption. The effect of pH, initial concentration of Ni(II), contact time, adsorbent dosage and temperature on adsorption are investigated and the adsorption kinetics and equilibrium adsorption isotherm is also observed. It is noted that up to 96% of Ni(II) concentration can be reduced with this alumina based nanocomposite incorporated with ZnO.