Porous Organic Polymers:Synthesis,Characterization And Research On Adsorption Of Pollutants And Recovery Of Precious Metals

Porous organic polymers(POPs)are highly cross-linked,amorphous,porous organic materials with significant specific surface area,adjustable pore size,stable chemical structure,and highly conjugated framework,it is widely used in the fields of biomedicine,gas capture,sewage treatment,and precious metal recovery.With the rapid development of the global economy and the continuous rise of some industries,it is difficult to prevent some toxic and harmful substances from being discharged into rivers,seas and lakes.For example,dye-containing wastewater produced by printing plants,heavy metal ion-containing wastewater produced by electronic machinery plants,and precious metal-containing wastewater produced by metallurgical plants,etc.Effectively removing the above-mentioned impurities from wastewater is of great significance to the natural ecosystem and human safety.And it is worth noting that because precious metals are non-renewable energy sources,effective recovery of precious metals also has certain economic value.Among the many methods,the adsorption method is widely used in sewage treatment and precious metal recovery due to its simplicity,high efficiency and low cost.Based on this,we designed two kinds of porous organic polymers to remove pollutants from wastewater and recover precious metals by adsorption respectively.The specific research contents are as follows:1.We took 5,10,15,20-tetra(4-nitrophenyl)porphyrin[H2TPP(NO2)4)]and octa(aminophenyltrioxysilane)(OAPS)as building units through coupling reaction to prepare a porous organic polymer based silsesquioxane-porphyrin(AzoPPOP).The characterization of the material not only confirmed the successful preparation of AzoPPOP,but also revealed that AzoPPOP has high specific surface area,abundant active sites,suitable pore volume,good thermal stability,high conjugated framework and negative charge.Based on these characteristics,it can be used to remove positively charged pollutants in wastewater.The results show that the maximum adsorption capacity of AzoPPOP for RhB is up to 1357.58 mg g-1.Mechanism studies have shown that this excellent adsorption performance is due to strong electrostatic interaction,high specific surface area,π-π stacking,and the presence of functional groups such as amino groups.Importantly,compared with other adsorbents,AzoPPOP also shows excellent adsorption performance for heavy metal ions.In addition,the purification experiment and recycling experiment of simulated wastewater prove the potential practical application ability of the material in the field of sewage treatment.2.Using 5,10,15,20-tetra(4-aminophenyl)porphyrin[H2TPP(NH2)4)]and 1,1’-bis(2,4-dinitrophenyl)-4,4’-Dibromide bipyridine(VL-Br),a porphyrin and viologen-linked porous organic polymer(V-PPOP-Br)was prepared by zincke reaction.The polymer can selectively adsorb noble metal ions,and the maximum adsorption capacity for Au(Ⅲ)is up to 787.40 mg g-1.The mechanism research proves that ion exchange,redox reaction and coordination effect together endow its with excellent adsorption performance for precious metal ions.In addition,practical application experiments and recycling experiments have further confirmed the potential application value of the polymer in the recovery of precious metals.