Abstract-Lead remotion was evaluated in a synthetic solution with 100 µg L -1 of Pb (II), using the lemon peel as a biosorbent. The adsorption capacity of the lemon peel at different pH values and particle sizes was studied.A maximum adsorption capacity of 19.556 mg g -1 was achieved with 0.5 g of biosorbent dose at pH 6, being able to remove up to 97.78% with the unmodified biomass and 93.83% after the cross-linking process of the adsorbent material.The adsorption kinetics is based on a Pseudo Second Order model for the biomass of lemon pre-treated with citric acid (R 2 = 0.9586) and not pre-treated (R 2 = 0.9408). It is concluded that lemon peel is a good precursor of lead adsorbent in aqueous solution.Keyword -Biosorption, adsorption kinetics, Freundlich isotherm, lead.
I. INTRODUCTIONThe increase in the concentration of heavy metals in water bodies caused by effluent discharges from anthropogenic activities is a growing environmental problem, because even at very low concentrations they are highly toxic[1], [2].Being cadmium, chromium, zinc, mercury, lead and nickel, the metals commonly found in wastewater; and of these, lead can affect the central nervous system, cause cancer and in more critical cases death due to its high toxicity even at low concentrations by binding with organic molecules [3], [4].Once the metals enter the aqueous and terrestrial media, they participate in chemical interactions of complexing, oxide-reduction and precipitation, modifying the characteristics of toxicity and bioavailability by converting from one chemical form to another, varying their toxic effect according to the chemical species of the ion, the degree of acidity-basicity and organic and inorganic components of the environment; factors determining the chemical behaviour of the ion in the formation of soluble or insoluble chemical forms that condition risks to biota and public health[5]- [9].Various technologies have been used for the removal of metal ions, among which are highlighted: chemical precipitation, chemical coagulation, oxidation, reduction, ion exchange, filtration, ultrafiltration, nanofiltration, adsorption (activated carbon, zeolites, silica gel), membrane technologies (reverse osmosis), electrochemical treatment (electrodialysis and electrocoagulation) and application of artificial wetlands (some stabilization), among others, resulting in many cases inefficient and costly [10]- [13]. Consequently, it is important to develop new detoxification technologies for such effluents and to chemically stabilize the compound [14]. This is why the development of new technologies based on domestic raw materials is a pending task for researchers from developing countries such as Colombia. Several studies have shown that the biomass of different species of lignocellulosic waste, bacteria, fungi and algae, are able to retain in their structures, metal ions that are found in aquatic environments [15]-[17].Biosorption is a physicochemical process that includes the phenomena of adsorption and absorption of molecules and allo...
