Synthesis And Properties Of Polyaspartic Acid As A Green Water Treatment Agent

Green chemistry, a new concept in chemistry developing in 21st century, is a kind of chemistry to prevent pollution from the very beginning. Polyaspartic acid (PASP) which is free phosphorus and biodegradable is one of the three green water treatment agents recognized through out the world.In this paper, Polyaspartic acid was synthesized with maleic anhydride and salvolatile as raw materials. The optimal conditions for synthesis are the molar ratio of maleic anhydride , salvolatile with 1:1.2 of the stoichiometric number, reaction time 1h at 180 ℃ ,under these conditions the molecular weight of PASPNa reaches 3500.The appropriate conditions of hydrolysis of polysuccinimide are as follows: the mass ratio of NaOH to polysuccinimide is 0.46:1, the concentration of NaOH is 10mol/L, hydrolyzic temperature is 25 ℃.In this thesis, correlating studies was performed, giving a direction for deep investigation on this theme.In terms of the characteristics of polyaspartic acid molecular structure, we devise the adsorption-deposit-chelate controlled Corrosion Inhibition synergistic model for the first time in this paper, and firstly create PASP-Zn2+-PBTCA three synergistic corrosion inhibitor composition. PASP is adsorbed on the metal surface through the backbone nitrogen atom which has lone-pair electron, the Zn(0H)2 strengthened adsorption film is formed on the metal surface by adding Zn2+, and adding PBTCA could control the film thickness due to the chelating of PBTCA for Zn2+.The synergistic inhibition effect of PASP, PBTCA and ZnCl2 for carbon steel was evaluated by means of weight loss methods during immersion. The experiments show that the composition of PASP, PBTCAand ZnCl2 have better synergistic corrosion inhibition for carbon steel than PASP ,PBTCA and ZnCl2, respectively. In a preferred embodiment, the adaptability of the composition to the water of different qualities is perfect, and the corrosion inhibition is particularly preferable in dynamic simulating experiments. Therefore, the tentative model is reasonably workable, which could offer the theoretical evidence to inhibition synergistic effect.The scale inhibition property for calcium carbonate, calcium phosphate, zinc scales and dispersing iron oxide were tested by the static scale inhibition test and the bubble test. The result of scale inhibition and dispersancy test inhicated that: polyaspartic acid had poor ability on calcium phosphate scale inhibition, zincil salt stabilization, and ferric oxide...