Removal of Mn(II) ions from synthetic solution using adsorbents based on apricot and peach shells

Abstract

Manganese occurs naturally in surface and groundwater due to mineral dissolution and leaching process, but also as a result of human activities such as manganese ore mining and processing, different alloys and salts production. It is also used as a gasoline additive, a component in ceramic/glass manufacturing, some agrochemicals (fungicides and fertilizers). Manganese is an essential element for the functioning of many enzymes and can serve as an activator of many others, but manganese is not biodegradable, and its bioaccumulation in living organisms can cause many diseases and disorders. In the present study, the biosorption efficiency for the manganese ions from synthetic solution by raw and modified apricot and peach shells has been investigated. These lignocellulosic materials were obtained from local juice factory, where they have been discharged as the waste. Removal of manganese ions was investigated using the following biosorbents: raw apricot shells (KK) (particle size <0.65 mm), modified KK with mixture of 2% alginate and bentonite (KKAlB), raw peach shells (particle size <100 μm) modified by: 2% alginate (KBAl), 2 mol/L HNO3 (KBM) and with the mixture of 10% FeCl3×6H2O and 0.1 mol/L KOH (KBFe). Experimental biosorption parameters were: initial concentration of manganese ions: 35 mg/L; m/V ratio: 5 g/L; contact time: 24h and initial pH value of the solutions: 4.5. The results have shown that KK is the most suitable and cost-effective biosorbent for the removal of manganese ions from aqueous solution. As apricot shells are widely available in the Republic of Serbia as food industry waste, application of this biosorbent can help in minimizing waste disposal and in water treatment at the same time.