Preparation And Study On The Mechanism Of A New Type Of Corrosion And Scale Inhibitor Without Phosphorus

In order to solve the problem of traditional phosphorus corrosion and scale inhibitors on water,this paper developed a new type of phosphorus-free corrosion and scale inhibitor.The composite corrosion inhibitor and scale inhibitor is modified polyepoxysuccinate(CSN-PESA),polyaspartic acid(PASP),hexamethylenetetramine,zinc chloride(ZnCl2),hydrolyzed polymaleic anhydride.(HPMA)A water treatment agent for recirculating cooling water systems.The specific research content of this article is as follows.(1)Firstly,thiourea was used to modify and synthesize polyepoxysuccinic acid,and orthogonal experiments were performed on the influencing factors of synthesis.The optimal synthesis conditions of modified polyepoxysuccinic acid(CSN-PESA)were as follows: The temperature was 90?,the molar ratio of polyepoxysuccinic acid to thiourea was 1.1:2,and the reaction time was 2 hours.The corrosion and scale inhibition performance of the synthesized modified polyepoxysuccinic acid(CSN-PESA)was measured.(2)Screening out corrosion and scale inhibitors with synergistic effect of modified polyepoxysuccinic acid(CSN-PESA),and determine the optimal ratio between the agents by orthogonal experiment.When the composite corrosion and scale inhibitor(FH)CSN-PESA: PASP: HPMA: ZnCl2: hexamethylene tetramine = 9: 6: 6: 4: 5 the best corrosion and scale inhibition.When the compound corrosion and scale inhibitor(FH)addition amount reached 18mg/L,the calcium carbonate scale inhibition efficiency reached 98.9%,and the scale inhibition rate of the traditional phosphorus scale and scale inhibitor PBTCA was only 88.5%.The composite corrosion resistance The corrosion inhibition efficiency of FH on carbon steel can reach 99.3%,and the corrosion rate can be reduced to about 0.004mm/a,while the corrosion inhibition rate of traditional phosphorus corrosion and scale inhibitor PBTCA is only 89.1%.The composite corrosion and scale inhibitor(FH)has good biodegradability and does not contain phosphorus and does not cause environmental pollution.(3)The electrochemical,SEM,and X-ray diffraction(XRD)methods were used to analyze the mechanism of the corrosion and scale inhibitors of the composite corrosion and scale inhibitor(FH).Through the polarization curve test,it was found that the corrosion potential moves in the positive direction as the concentration of the composite corrosion inhibitor increases,indicating that the composite corrosion and scale inhibitor is an inhibitor of the anode type,and the Langmuir isotherm adsorption model was used to In the mode of carbon steel adsorption,the composite corrosion and scale inhibitor has both physical adsorption caused by electrostatic action and chemical adsorption formed by chemical action.Through electron microscope scanning and analysis of carbon steel coupons,it can be seen that the composite corrosion and scale inhibitor(FH)adsorbs on the surface of carbon steel to form a corrosion-inhibiting film,which inhibits the corrosion of carbon steel.Through the electron microscope scanning and analysis of calcium carbonate scale,it was found that on the one hand,the composite corrosion and scale inhibitor(FH)can inhibit the growth of calcium carbonate crystals and cause lattice distortion of the crystals.On the other hand,the corrosion and scale inhibitor molecules can hydrate in water.Metal ions,thereby inhibiting the formation of calcium scale.