Corrosion Inhibition And Catalytic Properties Of Keggin Sandwich-type Tungsto-arsenate/-antimonite/-bismuthate Estertin Derivatives

Three Keggin Sandwich-type tungsto-arsenate/-antimonate/-bismuthate estertin derivatives,Na6K8[{Sn(CH2)2COO}2(B-?-AsW9O33)2]·25H2O,K4Na6[?Sn(C3H4O2)?2{Sn(C3H4O2)(H2O)?2(B-?-SbW9033)2]·14H2O and Na6K4[?Sn(C3H4O2)?2?Sn(C3H4O2)(H2O)}2(B-?-BiW9O33)2]·21H2O(Abbreviated as AsW9-RSn,SbW9-RSn and BiW9-RSn,respectively)were synthesized based on our previous work.The corrosion performance,the catalytic activities for the oxidation of cyclohexanol and the photocatalytic degradation of rhodamine B(RhB)were evaluated.Furthermore,A new boat-like POM compound{C(NH2)3}Na10K7[(W4O16){Sn(CH2)2COO}4(B-?-AsW9O33)2]·25H2O(Abbreviated as AsW9-RSn-1)was obtained after isolating AsW9-RSn,and can be synthesized in the optimum conditions.AsW9-RSn-1 was also characterized by IR,TG,UV,XRD,CV,NMR and other related analytic methods.In addition,the catalytic performances for the oxidation of cyclohexanol,the degradation of RhB and catalytic oxidation of simulated enzyme were studied.1.The oxidation catalytic properties for the oxidation of cyclohexanol of these compounds including AsW9-RSn,SbW9-RSn,BiW9-RSn,AsW9-RSn-1 and their parent compounds were explored.These carboxyethyltin decorated POMs have good catalytic activities,and their catalytic activities are significantly higher than those of the parent compounds,and the catalysts can be reused for multiple runs without loss of catalytic activity.2.The photocatalytic degradation of RhB of four compounds and their parent compounds were researched.The experimental results show that these compounds have good capability of degradation under the proper pH and can be recycled.The degradation efficiency of RhB was about 95%when the molar ratio of AsW9-RSn-1 to RhB was 1:16.3.Selecting o-phenylendiamine(OPD)/POM/H2O2 system as a mimic enzyme to explore the catalytic role of simulation of AsW9-RSn-1.With the change of the concentration of hydrogen peroxide,POMs on the substrate OPD showed certain effect,suggesting that this kind of compounds have the ability of replacing enzyme,and can provide a new approach to detect H2O2 instead of an enzyme biosensor.4.Using AsW9-RSn,SbW9-RSn,BiW9-RSn,AsW9-RSn-1 and their parent compounds as corrosion inhibitors,the corrosion inhibition on 20#carbon steel in tap water were preliminarily evaluated through static and dynamic weight-loss experiments and electrochemical method.The experimental results show that these compounds have good corrosion inhibition in the certain concentration range.