| Porous organic polymers(POPs),benefited from abundant pores,high specific surface area,dense active sites,stable framework and regular hierarchical structure,which has a wide range of applications and good performance in biology,medicine,environment and other fields.Among the large family of porous organic polymer materials,the POPs based on porphyrin and phthalocyanine have attracted close attention for their excellent material properties and excellent application performance,and ionic porphyrin and phthalocyanine porous organic polymers have further expanded their application scope due to their electrical properties.As one of the most common precious metals,gold has played an important role in the long history of mankind.With the development of the times,gold is not only used as money and jewelry,but also has a good application prospect in electronic equipment,precision instruments,aerospace and other fields.However,the earth’s gold reserves are extremely limited,and the mining of gold ores and the extraction of gold are extremely tedious,thus the recovery of gold is particularly urgent.Researchers have recently found that gold-containing e-waste contains far more gold than gold ore,and recycling the gold could not only reuse a valuable resource,but also protect the environment.Among the numerous gold recovery methods,adsorption is widely used due to its advantages of easy operation,low cost and diverse materials.Combined with the above background,we designed and synthesized two kinds of ionic porphyrin and phthalocyanine porous organic polymers and used them as adsorbents in the adsorption and recovery of gold.The following is the specific research content:1.2,9,16,23-tetraaminophthalocyanine(H2Pc(NH2)4)and octa-(aminophenyl)-t8silsesquioxane(OAPS)were selected as monomers and connected through azo bond,a phthalocyanine-based cross-linked polyamine POPs was prepared and named Pc-POSS-POPs.The highly cross-linked structure,abundant active sites and broad visible and near infrared light absorption spectra of the material were confirmed by various characterization methods.Based on the above advantages,the material was applied to the adsorption and recovery of gold,and showed excellent adsorption performance,the maximum adsorption capacity reached 862.07 mg/g.Under the condition of illumination,the adsorption capacity can be further increased,up to 1026.87 mg/g.Through the discussion of adsorption mechanism,the excellent adsorption performance of the material is mainly due to the nitrogen sites in the material and the combination of protonated amino(-NH4+)and AuCl4-.In addition,the material also has good selectivity,reusability and practical application.2.By using bottom-up one-pot method,ionic monomer(AM-1)containing imidazole group was directly polymerized with pyrrole,so as to prepare an ionic POPs containing porphyrin group,labeled Imi-PPOPs-Br.Thanks to the introduction of a large number of positively charged ion units and the formation of porphyrin units,the adsorption performance of material for gold is ideal,and the maximum adsorption capacity of 1543 mg/g.Theoretical calculation and related mechanism study show that the excellent adsorption performance is mainly due to the electrostatic attraction between the material and AuCl4-anion,the bonding between gold and nitrogen sites and the reduction of trivalent gold.In addition,the excellent selectivity and reusability of the material were also proved in the experiment. |
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