Adsorption of Pb (II) from Aqueous Solution Using some Agricultural Waste as Low Cost Adsorbent Materials: Part 1

Agriculture waste, barley straw (BS), wheat straw (WS), Rhodes grass (RG) , cabbage (CB), outer watermelon peel (WM) and Alfalfa waste (AF) were evaluated as low cost adsorbents for adsorption of Pb(II) ions from artificially contaminated water. FTIR spectra for this adsorbents showed almost similar function group such as hydroxyl, amine and carboxylic. SEM and BET results showed that WM has the highest surface area, while CB was the highest pore size and pore volume compared to other adsorbents. The effect of pH, heavy metals concentration, and contact time on the adsorption capacity, were investigated. The optimum pH of Pb (II) solution was 6 and equilibrium contact time was 60 minute. The kinetic result revealed that pseudo-second order model is suitable to explain the kinetic of Pb (II) adsorption. The adsorption equilibrium data match well with Langmuir adsorption isotherm with higher regression coefficient (R ≈ 0.99). The adsorption capacity of the adsorbents for Pb (II) followed the order AF WM RG CB WS ≥ BS. The high adsorption capacity of these agriculture wastes make them low cost and an effective adsorbents materials for Pb (II) from aqueous solution.