The Synthesis Of The Hydroxamic Acid Resin And Its Adsorption Of Acid Mine Drainage Characteristics,

In this study, a new poly(hydroxamic acid) resin (PHA) was synthesized and its adsorption properties and mechanism to Cu2+ and Fe3+ were studied. The aplication in recovering Cu2+ from acid mine drainage (AMD) by PHA adsorption technology was carried out.Poly(methyl methacrylate-divinylbenzene) (PMMA-DVB) was prepared by cross linking suspension polymerization. PHA chelating resin was synthesized by the reaction of PMMA-DVB and hydroxylamine in base condition. The effect of temperature, reaction time and reactant ratio for productivity and structure performance of PMMA-DVB and adsorption capacities of PHA were investigated. PHA was charaterized by IR,elemental analysis, TG and so on.The results of adsorption in batch method indicate that the adsorption process of PHA reach equilibrium after 150 minutes. Adsorption capacities increase with the increase of temparature and the initial concentration of metal ions. Adsorption capacities is effected strongly by pH and the best pH for Cu2+ and Fe3+ are individually 5.0 and 2.8. The selectivity of PHA for Fe3+ is stronger in Cu2+-Fe3+ binary system. H2SO4 solutions were applied to desorption of metal ions on PHA, and the results indicate that elution and regeneration properties are very good. The results of adsorption in the column experiment indicate that with increasing the flow rate and Cu2+ initial concentration, the breakthrough point reached ahead, and the efficiency of the resin function groups decreased. The dynamic desorption experiment indicate that desorption rate increase with the increase of H2SO4 concentration and the decrease of flow rate, at determinate H2SO4 solutions volume.Adsorption kinetics, isotherm and thermodynamics were researched, and the adsorption mechanism of PHA to Cu2+ and Fe3+ was discussed. The adsorption process was controlled by liquid film diffusion, particle diffusion and chemical reaction simultaneously. The adsorption reaction approximately equal to first order reaction. Isotherm adsorption process can be well described by Langmuir models, which indicats that the adsorption is a monolayer one; In the process,â–³H is plus andâ–³G is negative, indicated that the adsorption of PHA for Cu2+ and Fe3+ is spontaneous and endothermic. IR contrastive analysis before and after adsorption reveal that Cu2+ and Fe3+ coordinate with hydroxamic acid group on PHA in adsorption.A project of neutralizing AMD by calcite to precipitate Fe3+ and then adsorbing Cu2+ by PHA was carried out. The effect of granularity and dosage of calcite on neutralization result was studied. The result indicate that neutralization efficiency increase with the increase of dosage and the decrease of granularity. The results of treating experiment by the calcite neutralization-PHA adsorption technique on certain AMD indicate that the effluent liquid reach emission standard, percent recovery for Cu2+ attained 92.85% and enrichment ratio was 9.85.