Synthesis And Performance Evaluation Of Ionic Liquid Grafted Carbon Dots Corrosion Inhibitor

Pure metals and their alloys are widely used in various fields.However,its application is severely affected by corrosion,especially in acidic environments,which can cause huge economic and energy losses.Therefore,anti-corrosion has always been the focus of attention.Methods of metal corrosion protection include coating,electroplating,and self-assembly.Among them,adding corrosion inhibitors is the most convenient and efficient method.However,most of the corrosion inhibitors are organic compounds with poor performance,solubility,volatility and toxicity.With the increase of environmental awareness,these corrosion inhibitors are severely restricted.Therefore,it is of great significance to develop high-performance,environmentally friendly,and highly soluble corrosion inhibitors.In recent years,carbon dots have been deeply loved by researchers because of their green environmental protection,excellent biocompatibility and fluorescence.Although there is no unified explanation for its luminescence mechanism,most scholars believe that the fluorescence of carbon dots comes from its surface structure,and the doping of impurity elements changes the band structure of its surface state.The higher the degree of doping,the narrower the band gap.,And finally lead to the shift of the emission wavelength.It is inferred that because these carbon dot structures contain a variety of negatively charged atoms(such as N,S,and O)and conjugated π bonds at the same time,the defect structure reduces the energy gap,which is beneficial to electrons.The gains,losses and transfers have a certain adsorption activity,so theoretically,carbon dots can be used as corrosion inhibitors to inhibit the corrosion of metals.In addition,ionic liquids have received widespread attention due to their low toxicity,easy recovery,and easy dissolution.The ionic liquid can be grafted to the carbon dots to improve its performance.However,the specific mechanism of action of ionic liquids and carbon point corrosion inhibitors is still unclear.Therefore,exploring ionic liquid carbon point corrosion inhibitors as corrosion inhibitors for acidified environments and revealing the relationship between the effect of corrosion inhibitors and molecular structure is of great significance to the development of corrosion inhibitors.Therefore,this article developed two carbon point corrosion inhibitors(NCD and SCD),and grafted them with ionic liquids(IL-NCD and IL-SCD),and passed the weightlessness experiment,electrochemical test,and established the isothermal adsorption model.Comparing the corrosion inhibition performance of corrosion inhibitors containing different adsorption active centers with computer simulation methods,and exploring the mechanism of action,the results of the research are as follows:(1)The research selects citric acid,ammonium citrate and thiourea as reaction materials,and synthesizes the corrosion inhibition performance of NCD and SCD through a simple one-step method.The corrosion inhibition efficiency of the two corrosion inhibitors first increased and then decreased with the increase of the concentration.When the addition amount of NCD is 150 mg/L,the corrosion inhibition effect is the best,but its corrosion inhibition efficiency is 44.09%;the best use concentration of SCD is 50 mg/L,the corrosion inhibition efficiency is the highest90.80%,and the SCD concentration is less than The corrosion inhibition effect is better at 100 mg/L,and the corrosion inhibition effect drops sharply when it exceeds 150 mg/L.(2)Amino-terminated imidazole ionic liquid was synthesized using 1-(3-aminopropyl)imidazole and 1-bromo n-hexane,and grafted onto the carbon point corrosion inhibitor to synthesize IL-NCD and IL-SCD After the weight loss method,it is found that the corrosion inhibition performance of the two corrosion inhibitors after the ionic liquid medium has been greatly improved.Among them,the corrosion inhibition performance of IL-NCD increases with the increase of the concentration of the corrosion inhibitor,and its corrosion inhibition efficiency slows from 97.488%Increase to 97.456%.For IL-SCD,the corrosion inhibitor has the best corrosion inhibition effect at 100 mg/L,and the corrosion inhibition efficiency is 96.95%-97.106%in the range of 50 mg/L to 200 mg/L.(3)Using molecular dynamics simulation and density functional theory(DFT)methods to study the effect of substitution of pyridine N and pyrrole N by S atoms on its performance,and the analysis of the frontier orbital distribution and global reactivity studies found that S atoms Doping will reduce the energy gap of the analysis and increase the reactivity of the molecule.Through the local reactivity,it is found that pyrrole N is an important reactive center in the three molecules.It is both an electrophilic active center and a nucleophilic active center,while S The doping of atoms enhances the nucleophilic activity of the molecule,thereby increasing the molecular activity;molecular dynamics simulations show that although NCD presents a parallel adsorption morphology,its adsorption distance on the metal surface is too far,resulting in a relatively strong adsorption strength.The film formation stability is poor.The adsorption position of NSCD-1 and NSCD-2 is not much different,and the adsorption energy is not much different,but NSCD-2 has a smaller adsorption angle,so the coverage of corrosion inhibitor Stronger,with better corrosion inhibition performance.The above research results show that the access of ionic liquid corrosion inhibitor has an important influence on the effect of carbon point corrosion inhibitor.