Synthesis And Performances Study Of Environmentally Friendly Scale Inhibitor And Corrosion Inhibitor Based On Amino Acid

In order to protect and afforest the environment,the state and water treatment industry have introduced some policies,which limit the using of toxic and high-phosphorus water treatment agents in recent years.At present,many enterprises and researchers are focusing on the development of degradable and environmental friendly water treatment agent.Therefore,in this paper,three phosphorus-free,green water treatment agents based on amino acid have been synthesized and their performances have been studied,which lays a certain experimental foundation and theoretical basis for the development of new green water treatment agent.The details as follows:1.Fluorescent-tagged polyaspartic acid derivative（Gly-Try-PASP）was synthesized by modified polyaspartic acid（PASP）with glycine（Gly）and tryptophan（Try）.The polymer was characterized by Fourier transform infrared spectrometry（FTIR）,thermogravimetric analysis（TGA）and fluorescent spectrophotometer,respectively.The scale and corrosion inhibition performances of Gly-Try-PASP were studied by static method,electrochemical impedance spectroscopy（EIS）and polarization curve.Then the inhibition mechanisms were explored by scanning electron microscope（SEM）,X-ray diffraction（XRD）and electrochemical results.The results showed Gly-Try-PASP had good fluorescent performance,scale and corrosion inhibition performances.The CaSO₄ and CaCO₃ inhibition efficiencies of Gly-Try-PASP were 99.7%and 78.6%,respectively.The corrosion inhibition efficiency of Gly-Try-PASP was 81.7%when it compounded with 2 mg/L Zn²⁺.The inhibition mechanism study revealed that Gly-Try-PASP could change the morphology and crystal structure of CaCO₃ and CaSO₄ and inhibit anodic iron dissolution reaction by forming a protect film on the carbon steel surface,so as to achieve the scale and corrosion inhibition performance.2.An environment-friendly inhibitor,Curcumin-Citric acid-Aspartic acid（PCCA）polymer was synthesized by one step using solvent-free and catalyst-free green synthesis method with natural pigment curcumin as fluorescent monomer and citric acid,aspartic acid as functional monomers.The results showed that PCCA had good thermostability,excellent fluorescent performance（the linear correlation coefficient R² of fluorescent intensity and concentration is 0.9997）and great scale inhibition performances.The CaCO₃ and CaSO₄ scale inhibition efficiencies of PCCA were 99.7%and 98.8%,and the PCCA also had a good environment adaptability to inhibit CaSO₄ growth.Moreover,PCCA acted as a mixed-typed inhibitor can restrict anode and cathode reactions with corrosion inhibition efficiency of 84.1%.The scale and corrosion inhibition mechanisms of PCCA were studied and the results showed the inhibition effects of PCCA against CaSO₄ were lattice distortion,chelation and dispersion while only chelation and dispersion effect for CaCO₃ scale inhibition.The adsorption of PCCA on carbon steel followed Langmuir adsorption model,which was composed of chemical adsorption and physical adsorption.Not only the raw materials and synthesis process are environmentally friendly but also the PCCA has excellent scale inhibition performance,which provided a new idea and possibility for the development and production of green fluorescent-tagged scale inhibitor.3.The dextran derivative（Dex-Try）was synthesized by using tryptophan modified dextran,which can effectively inhibit the corrosion of carbon steel in HCl solution.The results by electrochemical test showed that the molar ratio of dextran and tryptophan had great influence on the corrosion inhibition performance of Dex-Try and the Dex-Try had the best inhibition performance when the molar ratio of dextran and tryptophan was2:1.The Dex-Try can act as mixed type inhibitor with inhibition efficiency of 87.1%in the concentration of 400 mg/L.The adsorption of Dex-Try on carbon steel surface followed Langmuir adsorption model,which was consist of physical and chemical adsorption.The Dex-try had stable corrosion inhibition performance at the ordinary temperature（25-40°C）,but its application range were 50-200 mg/L at 40°C.The research further expands the application scope of dextran.