Biosorptive Nickel Removal by Fruit Peel Waste: Batch, Kinetic and Isotherm Studies

Abstract

Heavy metal removal can be carried out by physical, chemical and biological methods. The most common methods used for heavy metal removal include adsorption, ion exchange, electro dialysis, membrane separation, activated sludge process, trickling filters, precipitation, coagulation etc. Each method has certain advantages and disadvantages. The selection of suitable methods depends on effluent quality and quantity, recoverability, economy and prescribed regulatory limits. Use of waste material for waste water treatment is widely explored area of investigation. There is scope for improvement in heavy metal treatment due to availability of wide variety of waste material. The current investigation is aimed at studying the ability of fruit peel waste for removal of heavy metal. From literature it was found that the waste containing pectin has ability to accumulate nickel. In this research high pectin waste namely Orange, banana and Mosambi fruit peel waste were analyzed for its ability to remove nickel from synthetic effluent.  For all three sorbent materials initially steep fall in concentration was observed in initial increase in adsorbent dosages upto 6 grams. It was observed that the nickel uptake followed Freundlich isotherm with R² value of 0.932. The constant n and k in Freundlich equation were found to be 0.219 and 5.70 X 10^-12 respectively. The Langmuir isotherm was found unsatisfactory for describing the nickel uptake with R² value of 0.810. The Nickel uptake follows both first and second order kinetics with R² values more than 0.96 for all sorbent materials.