Study On Preparation And Performance Of Multi-branched Silica Scale Inhibitor

In industrial circulating water systems such as oil fields,steam boilers,reverse osmosis membranes,and paper making,silica in raw water and circulating water is easy to deposit on the surface of equipment,affecting the normal operation of the system.At present,it is a common method to add scale inhibitors to circulating water.However,the common scale inhibitors anionic polymers have a mediocre control effect on the colloidal silica scale.Therefore,it is very important to develop a scale inhibitor that can effectively inhibit silica scale.In this paper,ethylenediamine(EDA),diethylenetriamine(DETA),and triethylenetetramine(TETA)were used as nuclei to synthesize polyamide-amine dendrimers(PAMAM)of different generations by the divergent method.The chemical structure of the product was characterized by Fourier-transformed infrared spectroscopy(FTIR),elemental analysis and hydrogen nuclear magnetic resonance spectroscopy,and the results showed that the structure of the product was consistent with the theoretical structure.The static scale inhibition method was used to investigate the scale inhibition effect of the synthesized series of dendrimers on colloidal silicon.The research results show that dendrimers of various generations have different inhibition effects on the formation of silica scales to varying degrees.The scale inhibition effect is mainly affected by the product generations,the amount of scale inhibitor addition and the p H value of the system.In addition,when the initial dissolved silicon is 500 mg/L,p H=7,and the amount of scale inhibitor addition is 40 mg/L,in the PAMAM with the nuclear of ethylenediamine(EDA),diethylenetriamine(DETA),and triethylenetetramine(TETA),the 1.0 generation has the best scale inhibition,and the scale inhibition rate is 1.0 G(79.61%)> 1.0 G(N5)(70.83%)>1.0 G(N6)(64.82%).The rate decreases with the increase of the degree of branching of the dendrimer.In this study,molecular dynamics(MD)simulation methods are used to study the interaction between the dendrimers with DETA as the core and the monosilicic acid in solution,and the inhibition mechanism of PAMAM on silica was further explored.The binding energy between dendrimers and monosilicic acid,the radial distribution function of oxygen atoms in dendrimers and hydrogen atoms in monosilicic acid were calculated.The study found that the order of binding energy is consistent with the scale inhibition results obtained in the experiment,indicating that the stronger the interaction,the better the scale inhibition effect.The research results of radial distribution function show that the adsorption between PAMAM and monosilicic acid is mainly composed of electrostatic interaction,van der Waals(vd W)interaction and H-bond interaction,where electrostatic interaction was dominant.