Synthesis And Mechanism Research Of A Novel Terpolymer Scale Inhibitor Based On β-cyclodextrin

In order to deal with the serious scaling problem of the industrial recycling cooling water system, an environmental-friendly monomer β-cyclodextrin(β-CD) was introduced to the preparation of a novel terpolymer scale inhibitor with maleic-anhydride(MA) and sodium-styrene-sulfonate(SSS). The effect of monomer adding pattern, initiator amount, monomer ratios, dropping time of medicament, reaction temperature and reaction time on the scale inhibition efficiency and conversion rate of monomers were investigated through single factor experiment method. The structure and morphology of the synthetic product as well as the calcium carbonate scale were characterized by FTIR and SEM for better analyzing and understanding the mechanisms of scale inhibition. Furthermore, corrosion inhibition ability of the synthetic product and its mechanisms were explored through Static Exposure Experiment and SEM analysis. The conclusions are as follows:(1) Free-radical polymerization of β-CD, MA and SSS as monomers, potassium persulfate(KPS) as initiator produced a novel terpolymer named β-CD-MA-SSS which has been investigated for its performance as scale inhibitor to prevent the deposition of calcium carbonate. Experimental results demonstrated that β-CD-MA-SSS presented excellent scale inhibition efficiency of 84.3% and high conversion rate of 97.6% under the optimal conditions as follows: the initiator contented 6%, the reaction monomers ratio SSS: MA=0.8:1, MA: β-CD=6:1, the reaction temperature 80 oC, reaction time 6h and dropping time 40 min when MA casted as a substrate and SSS, KPS were dropped into the system simultaneously.(2) FTIR illustrated that the synthetic product maintained the main structure and functional groups of β-CD. It also contained carboxy group, ester group, benzene ring and sulfonic acid groups as a result of the polymerization reaction of β-CD and MA with SSS. SEM indicated that β-CD-MA-SSS had a strong chelating ability of calcium and perfect dispersion ability of calcium carbonate.(3) The β-CD-MA-SSS also showed corrosion inhibition ability to a certain extent. The research on the effect of β-CD-MA-SSS dosage, pH and temperature indicated that, under the conditions of different pH, β-CD-MA-SSS dosage presented same effecting tends on corrosion inhibition rate. With the same dosage of β-CD-MA-SSS, high pH would benefit corrosion inhibition. As for the temperature, the effect was not particularly evident. SEM of corrosion of carbon steel speculated that the functional groups of β-CD-MA-SSS could reacted with metal of water passes by physical and chemical adsorption, thus inhibit or slow down the corrosion. The space steric hindrance of the cavity of β-CD isolated and resisted corrosion attack of the ions which also contributed to the corrosion inhibition.