The Adsorption Properties Of Polypyrrole/Attapulgite Composites With Selective Adsorption

With the development of society and the progress of mankind,human beings are reminded by an ancient and unavoidable problem,which is water pollution.The harm caused by water pollution is very serious,thus many scientis ts begin to study how to remove various pollutants in water.The studies mainly focus on the explanations of mechanism and seeking adsorptive materials with high efficiency.Polypyrrole?PPy?,as a conductive polymer,has preferencial adsorption to ions in solution via doping with different dopants.Based on two dopants,the paper proposes to use attapulgite?ATP?which has high surface area,low-cost and good adsorption property and polypyrrole to fabricate the advanced composites with selective adsorption property.The composites are used to adsorb the heavy metal ions and oxygen acid radical,which aims to reveal the major and minor influence factors and corresponding mechanism.In order to provide therorical guide for designing and fabricating selective adsorption materials,the selective rules of dpants and the influence of adsorbates properties are illuminated.Major conent was shown as follow:?1?ATP/PPy/Cl composites doped by small size ion were prepared by in situ polymerization.The influence of various factors are systemically studied.Some adsorption laws and mechanism about anion ion-Cr???or(Cr₂O₇^2-)were presented.The conclusion is that PPy composites own high efficient and quick adsorption efficiency after dopped by small size ion-Cl^-.After 10 min in 100mg/L Cr???solution,adsorption efficiency reached 99.78%when p H is 3.The mainly mechanism is combined with redox reaction,surface complexation electrostatic attraction and ions exchange.?2?After studied the influence of species and structure of dopants on adsorption properties of composites,SDS are chosen as a large size dopant.ATP/PPy/SDS composites doped with SDS are synthesized by in situ polymerization.The influence of various factors are systemically studied.After 45 min in 140mg/L Ni???solution,when p H is 8,adsorption efficiency reached 86.2%and adsorption capacity is 120.68mg/g,which is higher than other adsorbents.The high adsorption of Ni???is facilitated through both electrostatic attraction and ions exchange process because of large size dopant and negative charge of surface.?3?ATP/PPy/Cl and ATP/PPy/SDS were employed to adsrob Ni???and Cr???for exploring the relationship between dpants and selective adsorption of composites.All results fully illustrate that there is different response between two composites and two kinds ions.ATP/PPy/Cl preferentially adsorb Cr???,while ATP/PPy/SDS composites preferentially adsorb Ni???.The mechanism is similar to that of single ion except that there are some differenc es about electrostatic attraction and ion exchange due to different doped ions,which lead to different preference of adsorbents.?4?ATP/PPy/Cl was used to adsorb Cr???and P?V?.The influence of various factors are systemically studied.The influcnce of properties of anion ions on composites adsorption is discussed In 100 mg/L Cr???and P?V?solution,the adsorption efficiency of Cr???is always higher than that of P?V?during the contact time of 0.5¹2h.The equilibrium adsorption efficiency of Cr?V I?is 97.57%using0.2g adsorbent.The adsorption efficiency of Ni???is increased with adsorbent dosage increase after completed adsorption of Cr???,suggesting ATP/PPy/Cl composites prefer to remove Cr???.The adsorption mechanism of Cr???is similar to Cr???single system,while the adsorption of P?V?completely depend on the electrostatic attraction and ions exchange process.Obviously,the differences derive from the influence of adsorbate properties.?5?ATP/PPy/SDS composites were employed to remove Ni???and Cu???.The influence of various factors are systemically studied.The influcnce of properties of cation ions on composites adsorption is discussed.The results show after 25min in75mg/L solution the adsorption efficiency of Cu???and N i???is 96.43%and69.75%when p H is 6.It is obvious that the composites prefer to adsorb Cu???rather than Ni???due to their hydrous radium and redox properties.The study of mechanism verifies that some surface complexes are formed between Cu???an d adsorbents,and redox reactions occur at the same time.While the adsorption of Ni???is facilitated through electrostatic attraction and ions exchange.Fortunately,the reason made the adsorption efficiency of Cu???high is that the adsorption impetus of Cu???is much larger than that of Ni???,which relates to the properties of adsorbents.