Study On Anticorrosion Mechanism And Bactericidalproperties Of Ionic Liquid Copper-based Corrosion Inhibitor

Metal materials play an important role in all fields of human production and life.Among them,copper and its alloys are continuously put into use with the development of society.However,in the face of complex media environments,these copper metals may be damaged by electrochemical corrosion or microbial corrosion at any time.Therefore,in order to ensure the stable and durable work of copper in these environments,and to meet the needs of industrial production and life,it is necessary to take effective protection measures.As a new material with the advantages of low vapor pressure,low toxicity and high stability,ionic liquids have been used for corrosion inhibition and sterilization,and have achieved extremely efficient results.This makes the ionic liquid with dual functions of corrosion inhibition and sterilization have broad application prospects in the field of corrosion in the prevention and control of dual corrosion of electrochemical corrosion and microbial corrosion.Therefore,in this study,ionic liquids with different structures were synthesized,and their corrosion inhibition and bactericidal properties were investigated.Using benzotriazole?BTA?and benzimidazole?BIA?as cationic ligands,naphthalenesulfonic acid?NSA?,benzenesulfonic acid?BSA?and phosphoric acid?PA?as an anionic ligand,using proton transfer method,one-step synthesis of five kinds of ionic liquids BTANSA,BTABSA,BTAPA,BIABSA and BIAPA,followed by nuclear magnetic resonance spectroscopy and infrared spectroscopy for structural characterization.Thermogravimetric analysis found ions of different structures Liquids have different thermal stability.The static weight loss method was used to evaluate the corrosion inhibition performance of each ionic liquid.The results show that in nitric acid media,the higher the concentration of ionic liquid,the better the corrosion inhibition effect,and temperature and acid concentration are also important factors affecting the corrosion inhibition effect of ionic liquid.Under normal circumstances,normal temperature and low acid concentration are beneficial to Improve the corrosion inhibition performance of ionic liquids.Comparing the corrosion inhibition effects of five ionic liquids,it is found that BTANSA has the best effect,and its corrosion inhibition rate reaches99.8%,while the corrosion inhibition rate can be reduced to 0.02 g m^-2 h^-1.The polarization curve and electrochemical impedance spectroscopy were used to study the corrosion inhibition mechanism of ionic liquids.Experimental results show that BTANSA and BTABSA are mixed corrosion inhibitors that can simultaneously inhibit anodic and cathodic reactions,but cathodic inhibition is the main factor.In addition,electrochemical experiments also found that BTANSA and BRASA mainly slow down the electrochemical corrosion of copper by inhibiting the charge transfer process.The static weight loss method was used to continue to study the corrosion of copper strips by sulfate reducing bacteria?SRB?,and the corrosion mechanism of SRB was investigated by electrochemical methods.The ionic liquid was added to the culture medium,and the killing effect of BTANSA on SRB was investigated.The results show that there is a significant relationship between the corrosion degree of SRB to copper and its quantity.The greater the number of SRBs,the faster the corrosion rate of copper pieces.In the sterilization experiment,BTANSA showed a good killing effect on SRB.When the BTANSA concentration was 0.05-0.20 g L^-1,the number of SRB was significantly reduced,and the killing rate could reach more than 99%;when the concentration increased When it is above 0.50 mg L^-1,SRB is completely killed.