Performance Of Amino Methylene Phosphonic Acid Resin In Removal Of Pb(Ⅱ) From Contaminated Water

Chelating resin adsorption technology had good application prospects in heavy metal wastewater treatment. In this study, the adsorption and desorption behavior of aqueous Pb(II) on amino methylene phosphonic acid resin D860was investigated systematically. And the performance and application potential of using D860in the treatment of actual lead containing wastewater was evaluated.Firstly, three kinds of resins, a macroporous ion exchange resin D001, iminodiacetic acid resin D851and D860were compared in terms of static adsorption performance toward Pb(II). And D860displayed better adsorption capacities and adsorption selectivity towards Pb(II) than the other two resins. D860exhibited better Pb(II) removal efficiency in the pH range of4-6. Elevating temperature from10℃to30℃was beneficial for increasing adsorption efficiency and accelerating adsorption reaction rates. The time required for adsorption equilibrium was increased with higher initial concentration of Pb(II) in aqueous solution.In terms of desorption, firstly, four desorption agents, hydrochloric acid (HC1), nitric acid, acetic acid and EDTA were compared for the desorption of Pb(II) from the surface of D860, and HCl was chosen as the desorption agent after considering the regeneration rate, economic factors and environmental friendliness. The results showed that under the same HCl concentration, the time required for desorption equilibrium was shorter when lower amount of Pb(II) was adsorbed onto D860. Increasing the concentration of HCl was beneficial for desorption. Through comparing the solubility of Pb(II) in HCl with different concentrations, solubility was identified as the key factor for controlling the desorption of D860by HCl. The concentration and temperature of HCl significantly influenced the solubility of Pb(II) in HCl, and further influenced the desorption efficiency of D860. The optimized parameter in fixed-bed column desorption were summarized as follows, HCl concentration,1.0mol-L-1; desorption flow rate,1BV-h"’(Bed Volume); desorption temperature,30℃; HCl dosage,6BV.On the basis of above results, pilot adsorption-desorption study was carried out using Pb-containing simulated wastewater. The water quality of treated effluent by D860column was stable for four consecutive cycles, the concentration of Pb in influent was0.3mg-L"1, and it was lower than100μg-L-1in effluent.Based on the results of laboratory study, we built a industrialized unit with treatment capacity of1200tons per day for a concentrator plant tailings wastewater. With the optimal factors obtained from experiment, the treatment plant had good performance for continuous operation in approximately one year. The concentration of Pb in influent was0.3mg-L-1, while it was lower than100μg·L-1in effluent. The results of this thesis and industrial installations show that amino methylene phosphonic acid resin has excellent application potential in the removal of trace level Pb(II) from contaminated waterbodies.