Study On Softening And Desalting Of Industrial Circulating Water Based On Electrochemical Method

As an environmentally friendly and low-cost treatment method,electrochemical methods are attracting more and more attention from researchers in the industrial water treatment industry.Microelectrolysis and electrosorption are two representative methods.Micro-electrolysis softening technology is a technology that can“active descaling”.It can be used in the treatment of industrial circulating water,which can replace the scale inhibitor and save costs.The electrosorption demineralization technology is applied to the treatment of industrial circulating water,which can effectively improve the water quality,greatly increase the concentration ratio of circulating cooling water,thereby avoiding excessive water supply and reducing the amount of sewage discharged,improving the recycling rate of the entire system,and realizing circulating water."Zero emissions."In this paper,a micro-electrolysis softening test device was constructed,with calcium ion as the target pollutant.The characteristics of micro-electrolysis to remove hardness were studied.The effect of micro-electrolytic device on hardness removal under different operating conditions was explored.The operating conditions were optimized and micro-electrolysis was performed.The cathode material of the softening device was compared.(1)By continuously running the micro-electrolytic device for 300 hours,it was found that under the condition that the operating parameters such as current density,plate spacing and residence time are constant,the micro-electrolytic device is removed even if it is continuously operated for a long time,the ability of hardness does not change significantly over time.(2)The effect of current density,plate spacing and residence time on the hardness of micro-electrolytic device to remove circulating water was studied by single-factor method.The best operating parameters of micro-electrolytic device were current density 28 A/m~2,The distance between the plates is 5cm and the hydraulic retention time is 30 min.At this time,the micro-electrolytic device has better treatment effect on the circulating cooling water,and the corrosion degree of the plates is lower.(3)By studying the effects of three kinds of cathode materials,such as stainless steel plate,cast iron plate and titanium plate,on the performance of the micro-electrolytic device,it was found that the three cathode materials showed a considerable hardness removal rate,and the difference was not significant,but combined with the treatment effect,energy consumption and cost.In other respects,the stainless steel plate is the most suitable material for the cathode of the microelectrolysis device in industrial applications.In this paper,an electrosorption demineralization test device was constructed.The sodium chloride solution was used as the treatment object,and activated carbon fiber(ACF)was used as the electrode of the electrosorption device.The desalination effect of the electrosorption device under different conditions was investigated,and the regeneration of the ACF electrode was studied.The properties of ACF were modified by nitric acid and sodium hydroxide to study the effect of modification on its desalination ability.The materials were characterized by field emission scanning electron microscopy and specific surface and pore size analysis.The reason for the change in ACF desalination effect.(1)Through the single factor experiment,combined with the actual situation,the best parameters of electrosorption demineralization technology are voltage 2.1 V,plate spacing 4 mm,circulation flow rate 5.00cm/min,initial concentration 1000?s/cm.Under this condition,when the electrosorption equilibrium is reached,the demineralization rate of the device is 38.70%,and the electrode adsorption amount is 13.62 mg/g.(2)Under the optimal operating conditions,the ACF adsorption-desorption cycle experiment shows that the ACF electrode has been maintained well.Demineralization effect,good adsorption performance and regeneration performance.(3)Modification of ACF electrode by different concentrations of nitric acid and sodium hydroxide,it is found that both nitric acid and sodium hydroxide can improve the electrosorption effect of ACF electrode to a certain extent.However,the overall effect is not significant.The comparison shows that the desulphurization ability of sodium hydroxide on the ACF electrode is slightly lower than that of nitric acid.(4)By nitrogen isothermal adsorption and desorption test on the ACF before and after modification,it is found that nitric acid and sodium hydroxide The BET specific surface area,total pore volume and micropore volume of the modified ACF have a certain degree of increase,correspondingly the pore size has been reduced to some extent,and the specific surface of the ACF modified by sodium hydroxide Effect of pore size distribution of far less nitric acid,nitric acid can be better described specific surface area increases the ACF,pore volume and pore size distribution adjustment so that the activated carbon fiber can be better applied to the electric absorption,increase the adsorption amount of the electrode.