Reclaiming Siliver Of Ag~+-imprinting Adsorbent And Photocatalysis Degradation Of Organic Dye Wastes

With the development of electroplating, coinage, medication and chemical engineering, environment has been seriously damaged by wastewater containing heavy metal ions. Simultaneously, Heavy metals are widely used in various industries fields due to their excellent and multifunctional properties. So it has been the urgent assignment to recover the valuable metallic elements in the wastewater effectively.Using the surface molecular imprinting technology, the Ag+-imprinted adsorbent(Ag-IB) for the treatment of silver-containing wastewater was prepared, which showed higher adsorption affinity and selectivity for the imprinting ion (Ag+) than the other non-imprinting metal ions. Batch adsorption experiments were carried out such as imprinted Ag+concentration, agitation time, temperature, initial Ag+concentration and so on. The optimal imprinted Ag+concentration for preparing Ag-IB was2.0mg/g (biomass). The maximum adsorption capacity was199.2mg/g at the initial Ag+concentration of1200.0mg/L and the adsorbent dosage of3.0g/L, which was much higher than that of previous work. And adsorption for Ag+could be obviously improved by adding trace NanoTiO2. After TiO2loading, adsorption for Ag+could be improved about25.0%at initial Ag+concentration of1000.0mg/L. The adsorbent could be easily desorbed by using0.1M Na2S2O3solution as a desorbent at room temperature. The SEM and XPS analysis showed that, noble metal silver could be well adsorbed by Ag-IB and formed regular nanoparticles. And the FTIR analysis indicated that TiO2combined with Ag-IB through hydrogen bonds.In addition, Ag-IB after adsorption for Ag+that could be used in the degradation of dyes such as MO in UV irradiation. The maximal degradation rate of MO reached over93%at Ag+adsorption capacity of78.00mg/g after5h. And Methylene Blue (MB) and Sunset Yellow (SY) were studied and the degradation rates could be about70%and98%at Ag+adsorption capacity of36.92mg/g, respectively. XPS analysis showed that Ag+was reduced to Ag on Ag-IB surface.Finally, the interaction between the different adsorbents and Fe3+、 competitive adsorption of Ag+and Fe3+. Ag+、Cu2+were more easily replaced by Fe3+in contrast with Pb2+、Cr3+when adsorbed on all four adsorbents. The result implied that Fe3+could be used for recovering Ag+adsorbed on the adsorbents effectively.