Preparation And Application Of Double-hydrophilic Copolymer As Scale And Corrosion Inhibitor For Industrial Recycling Water

Recirculating cooling water systems,an important part in many industrial processes,means the water could be reused for many times.However,the reclaimed water constituents become special and complex after utilized for several periods,so it will cause more serious scaling and corrosion problems,which affect the normal operation of recycling cooling systems or even lead to security incidents.At present,research concerning effective method to lower the tendency to evolve precipitates and corrosion,focuses on chemical additives,as has the advantages of convenient and effective operation.But,most of these commercial compounds are expensive and toxic to human beings and the environment.For this reason,environmentally friendly inhibitor with both excellent scale and corrosion inhibition properties has become an imperative focus to water treatment technology.Isoprenyl polyethoxy carboxylate(TPEL)macromonomers,possessing polyethylene oxygen long chains,is synthesized by the reaction between isoprenyl oxy polyethylene glycol(TPEG)and succinic anhydride(SA).And then a series of scale and corrosion inhibitor copolymers acrylic acid-isoprenyl polyethoxy carboxylate(AA-TPEL)are synthesized by means of free radical polymerization using AA and TPEL as the monomers.The structural properties are identified by FT-IR,'HNMR,TGA and GPC analyses.In addition,polymerization process is studied on the influence of scale inhibition performance of scale inhibitors,and the optimal reaction conditions are determined.The inhibitory behavior of the polymer is determined by using static scale inhibition method.Scanning electron microscopy(SEM)and X-ray powder diffraction(XRD)is used to characterize the surface morphology and crystal form of calcium scales.Compared with several other current commercial inhibitors,AA-TPEL exhibits excellent ability to control calcium precipitation,with approximately 88.67%CaCO3 inhibition and 94.17%CaSO4 inhibition at levels of 8 mg/L and 3 mg/L respectively.It also maintain superior ability to prevent the formation of Ca3(PO4)2 scale with 100%inhibition efficiency at the low level of 5mg/L.AA-TPEL also displays superior efficiency even at increasing solution temperature,Ca2+concentration water system,and still shows stable treating effect in warm water for a long time.SEM?XRD and FT-IR indicate that morphology of calcium scales are completely changed or the crystal structure is changed in the presence of AA-TPEL.Weight loss test,potentiodynamic polarization and electrochemical impedance spectroscopy are employed to investigate the inhibitive properties and mechanism on mild steel corrosion.All measurements show that,AA-TPEL act as a mixed inhibitor,and the depressed corrosion current,boosted transfer resistance means that AA-TPEL display superior ability to prevent the corrosion of mild steel with approximately 83.21%inhibition efficiency at the low level of 10mg/L.the corrosion of mild carbon steel is control by AA-TPEL which is enslaved to the film of inhibitor molecules formed on the metal surface.