Heavy Metal Removal from Wastewater Using Low Cost Adsorbents

With the onset of industrialization mankind has witnessed various environmental issues in the society. This industrialization has not only brought development and prosperity but eventually disturbed the ecosystem. One of the impacts is visible, in form of water pollution. In the present study heavy metal contamination of water bodies has been discussed. Effluents from large number of industries viz., electroplating, leather, tannery, textile, pigment & dyes, paint, wood processing, petroleum refining, photographic film production etc., contains significant amount of heavy metals in their wastewater. The conventional methods of treatment of heavy metal contamination includes chemical precipitation, chemical oxidation, ion exchange, membrane separation, reverse osmosis, electro dialysis etc. These methods are costly, energy intensive and often associated with generation of toxic byproducts. Thus, the adsorption has been investigated as a cost effective method of removal of heavy metals from wastewater. In the present study various low cost adsorbent has been reviewed as an abatement of heavy metal pollution from wastewater. These adsorbent includes materials of natural origin like zeolites, clay, peat moss and chitin are found to be an effective agent for removal of toxic heavy metals like Pb, Cd, Zn, Cu, Ni, Hg, Cr etc. Apart from these various agricultural wastes like rice husk, neem bark, black gram, waste tea; Turkish coffee, walnut shell etc. were also established as a potent adsorbent for heavy metal removal. Beside that low cost industrial by products like fly ash, blast furnace sludge, waste slurry, lignin, iron (III) hydroxide and red mud, coffee husks, Areca waste, tea factory waste, sugar beet pulp, battery industry waste, sea nodule residue and grape stalk wastes have been explored for their technical feasibility to remove toxic heavy metals from contaminated water.