Synthesis And Study Ofglutamic Modified Polyether Copolymer As A Novel Non-Phosphorouswater Treatment Agent

Water is the source of human life, and the lifeblood of the national economy. China’s total water resources is rich, however, average per capita possession of water is small. The lack of water resources has been a serious problem in our country. The circulating cooling water used in petrochemical, chemical fertilizer, electricity and other industries occupies a great proportion in the whole water consumption. In order to conserve water resources and reduce pollution, the concentration ratio of industrial cooling water water was continuously improved. This lead to accelerated precipitation trend of some insoluble salt and serious problem of fouling. In the field of water treatment, chemical treatment is generally used to solve these problems, that is, to prevent scaling by adding scale inhibitors.According to the related literature, the chief aim of this study is to develop a novel greener inhibitor acrylic acid-allyloxy polyethoxy glutamate (AA/APEU). The structure of the new copolymer was characterized by fourier-transform infrared spectra (FT-IR) and’H-NMR. The inhibition property of the non-phosphorous copolymer towards calcium scale in the artificial cooling water and brackish seawater to acquire real and effective numbers. The micromorphology and crystal of calcium particles were investigated with combination of scanning electronic microscopy and X-ray powder diffraction analysis to discuss the inhibition mechanism of AA/APEU, respectively.APEU was prepared by esterification between a terminal hydroxyl group in APEG and one of the carboxyl groups in glutamic acid. The copolymer of AA/APEU was synthesized form allyloxy polyethoxy glutamate (APEU) and acrylic acid (AA) through free radical copolymerization in aqueous system. The analysis of fourier-transform infrared (FT-IR) and 1 H-NMR reveal that APEU has been synthesized successfully, and the free radical polymerization between APEU and AA has happened.The inhibition property of the non-phosphorous copolymer towards calcium scale in the artificial cooling water was studied through static scale inhibition tests and sea water concentration method. The experimental data show that, in circulating cooling water system, the inhibition ratio for CaCO3 is 76.8% at the dosage of 10 mg·L-1, while the inhibition ratio for CaSO4 is almost 100% at dosage of 2 mg·L-1. The solution transmittance of ferric oxide obtains 16.8% minimum value when using 4 mg·L-1 AA/APEU. Result of sea water concentration method showed that AA/APEU exhibited 77.7% calcium scale inhibition at a level of 5 mg·L-1. The scale inhibition efficiency increased slightly with the concentration of sea water. The comparison of AA/APEU with the commercially available water treatment agent shows that AAA/APEU is an excellent scale inhibition and dispersing agent, which is suitable for cooling water system and seawater desalination system.The surface morphology and crystal structure of calcium carbonate and calcium sulphate were studied by means of XRD and SEM. It indicates that the presence of AA/APEU affects the morphology and the size of calcium crystals significantly. It also makes the precipitates have higher disperse property in water solution. As a consequence, the precipitates can be easily disturbed by water turbulence. The mechanism of scale inhibition of AA/APEU is explained by the combination of lattice distortion and chelating dispersion. In the nucleation stage of calcium scale, crystal nucleus can not grow normally which is mainly caused by AA/APEU. In the crystal growth stage, the carboxylic groups of AA/APEU chelate with Ca2+ and form water soluble chelation, so that calcium scale is easy to disperse in water.A novel non-phosphorous copolymer acrylic acid-allyloxy polyethoxy glutamate (AA-APEU), which is biodegrade to some extent because there is an amino acid component in it, had been synthesized and developed as an efficient calcium scale inhibitor for cooling water system and sea water desalination system. This study provides a theoretical basis for the application of AA/APEU, which is expected to be applied in industrial water system.