Experimental Study On Environment-friendly Corrosion Inhibitor

Corrosion inhibitors inhibit the corrosion of corrosive media by special physical and chemical interactions at the interface between the metal and the corrosive medium.Reasonable use of corrosion inhibitor can effectively prevent the corrosion of metal in the corrosive medium.Corrosion inhibitor technology has become one of the most widely used methods in anti-corrosion technology because of its good effect and high economic efficiency.Corrosion inhibitors in acidic media,neutral media,alkaline media and gas medium are used in the widespread presence in petrochemical,machining,construction,chemical cleaning,instrumentation and other industries.At present,most of the corrosion inhibitors used in the concrete field is inorganic salt corrosion inhibitors,which can not effectively solve the protection problem of the cathode area.It is often used in combination with organic corrosion inhibitors.Many organic corrosion inhibitors can not meet the environment Compatibility with economics.Looking for functional,effective,low cost of environmentally friendly corrosion inhibitor has become the key to development.Chlorinated salt neutral,weak alkaline water medium widely present in a variety of circulating cooling water system,which need to add a large number of corrosion inhibitors to improve the service life of the equipment,especially the serious corrosion of salt water circulation system,in addition to The need for economic efficiency,the addition of corrosion inhibitor must also meet the low toxicity of environmental protection,to prevent the adverse effects of marine ecology and biological,new environmentally friendly corrosion inhibitor therefore has a huge market demand.Based on the above background,this study consists of three parts.In the first part,the corrosion of steel bars in the alkaline environment of reinforced concrete is studied.The optimized design of molybdenum series petroleum sulfonate composite rust inhibitor(corrosion inhibitor)is studied.The main research is on the low toxicity and environmental protection of sodium molybdate The main selection of sodium sulfonate,diethanolamine compound,according to the optimal design to carry out with a more efficient and economical anti-rust agent.The Electrochemical Impedance Spectroscopy(EIS)was used to analyze the electrochemical impedance spectra of the solution.The best ratio of sodium molybdate 300mg/L,diethanolamine 10mL/L,petroleum sulfonate 4mL/L.In the second part,L-ascorbic acid(Ascorbic Acid)was selected as the research object.The inhibition effect of l-ascorbic acid on mild steel was investigated by electrochemical polarization curves and electrochemical impedance spectroscopy in 3.5% NaCl solution.Electrochemical test results showed that l-ascorbic belonged a mainly cathode-controlling mixing type inhibitor in concrete which inhibits both anode and cathode reaction.The adsorption behavior of l-ascorbic acid on mild steel was subject to Langmuir adsorption isotherm.There are physical adsorption and chemical adsorption of two adsorption state,the best inhibition of the concentration of 10-3mol/L,corrosion efficiency up to 75.4%.On the basis of this study,the relationship between L-ascorbic acid and sodium molybdate and sodium citrate was discussed in depth,and the orthogonal test was established by weightlessness method.The optimal ratio of slow release was obtained.Anti-corrosion performance and corrosion inhibition law of etchant in neutral and alkaline environment.The optimum ratio of the corrosion inhibitor is 600mg/L,160mg/L,600mg/L,the inhibition rate is over 90%.At the same time,this paper attempts to improve the optimal screening method of compound corrosion inhibitor,and on this basis,the early evaluation mechanism of corrosion inhibitor is established,the important position of orthogonal test in optimization design and the reliability of analysis and evaluation of electrochemical method are determined.