Quantum Chemistry Studies On The Scale Inhibition Mechanism Of Water Treatment Chemicals Used In The Cooling Water Circulation System And It's Application

The structure and activity relationships(SAR)of seven methylene phosphonic acids,i.e.HEDP,ATMP,EDTMP,PAPEMP,K₆HDTMP,EDTMP,BHMT,PBTC and green scale inhibitor PESA,PASP,were studied systemically by using Density Functional Theory(DFT)method at B3LYP/6-31G level.Results of quantum chemical calculations indicated that nitrogen and phosphonate oxygen atoms in these molecules had more negative charges,which demonstrated that strong electrostatic interactions be-tween nitrogen or phosphonate oxygen atoms and calcium cations on the calcite crystal surface might be occurred,if the space between nitrogen and phosphonate oxygen atoms matching the calcium cations on the calcite crystal surfacee,it will be strongly buildup the adsorption between them,which induce calcite crystal to be aberrantce,effectively prevent it upgrowth.The relationship between molecular energy and dihedral angel is educed by molecular potential energy scanning using the semi-emprirical molecular orbital theory(PM3).Studies the effect of molecular flexibility and rigidity to scale inhibitor.It also studies the correlation of molecular structure,electronical structre and corrosion inhibitor performances,and resoults show that the corrosion inhibitor efficiency have great correlation with HOMO energy and the difference between the LUMO energy and HOMO energy.It should be considered that the adsorption film formed by corrosion inhibitor molecular and the metal on the surface of the metal or the function between the metal and the electron from nitrogen and oxygen atoms.A new type green corrosion and scale inhibitor are developed,the main scale inhibitor PESA,with corrosion inhibitor zincum,which is biodegradation and phosphate deficiency.the performance of corrosion and scale can reach to the traditional phosphorous alkaline water treatment chemicals used in the cooling water recirculation system.