Preparation And Characterization Of A New Type Of Coagulant Polymeric Aluminium Chloride Titanium

In the field of water treatment,the treatment technologies for surface water mainly include coagulation and sedimentation process,ozone-biological activated carbon process,electrochemical process and biofilm process,among which the coagulation and sedimentation process has high processing efficiency,simple structure,and low processing cost.Coagulation and sedimentation process has become an important front-end unit operation technology in the field of water treatment,which occupies an extremely important position in the water treatment system.The treatment effect of the coagulation and sedimentation process is affected by many factors,such as the characteristics of the coagulant,the dosage of the coagulant,the coagulation pH,the ionic strength in the water,and the hydraulic conditions.Among of the factors,the effect of coagulant dominates.Most of the coagulants used in water plants today are mainly based on inorganic polymer coagulants,such as PAC,PAFC,PFS and PAFS,etc.Although these macromolecular coagulants are superior to conventional coagulants in removing turbidity and color from water,there are still some problems that cannot be ignored.PAC is a polymer coagulant that has been used in recent years.PAC has significant effects when combined with other coagulants,but when used alone,the treatment effect is significantly reduced.In addition,PAC also has the disadvantages of small flocs produced by hydrolysis and slow sedimentation speed of the flocs,which are not conducive to improving the daily processing capacity of water plants.Therefore,it is of great significance to study the modification of the coagulant and enhance the coagulation characteristics of the coagulant.In this study,by measuring the pa rticle size and Zeta po tential of PATC,the influe nce of the amount of TiCl₄ added on the properties of PATC was studied.The results show that with the increasing amount of TiC l₄,the particle size of PATC increases first and then decreases.The particle size of PATC reaches its maximum at126 nm when the molar ratio of Ti to Al is 6:100.With the increasing amount of TiC l₄added,the Zeta potential of PATC increased continuously.When the molar ratio of Ti to Al was 4:100,the Zeta potential reached a maximum of 28.3 mV.When the addition of TiC l₄ was continued,the Zeta po tential of PATC is basically in a steady state.According to the infrared spectrum analysis,TiC l₄ participates in the polymerization reaction,forming a more complex structure and having a better ability to trap and sweep.By SEM,it can be seen that PATC has a larger breach structure than PAC and has a larger specific surface area improving t he adsorption efficiency of impurities and organics in water.The PATC has be tter charge neutralization and net trapp ing ability,and the coagulation performance will be greatly improved compared with TiC l₄.The PATC was prepared according to the molar ratio of Ti to Al,6:100.The advantages and disadvantages of PAC and PATC in removing turbidity were studied.The results show that the turbidity removal effect of PATC is be tter than that of PAC when the dosage is low,but when the dosage of coagulant exceeds 100?mol/L,the turbidity removal effect of PATC is weakened and the turbidity removal effect of PAC is lower.When the dosage of PAC and PATC is 100?mol/L,the effect of coagulation pH value on coagulation effect is explored.It is concluded that the effect of coagulation pH on the removal of turbidity is much smaller than that of PAC,and the turbidity of the effluent can reach below 1.0 NTU at p H=5.0⁹.0,and PAC has worse effect in the whole coagulation pH range,and the difference is more obvious in the neutral and weak alkaline environment.In the removal of organic matter,the optimum coagulation p H value of PAC is abo ut 6.0,while the op timum coa gulation p H of PATC is abo ut 7.0,which may be related to the hydrolysis,hydrolysate and degree of hydrolysis of the two coagulants in water.Moreover,the organic removal capacity of PATC is better than that of PAC,and the DOC content of effluent can be reduced to 1mg/L in the whole pH range.The optimum dosage of two coagulants was 100?mol/L,the best coagulation pH value of PAC was 6.0,and the optimum coagulation pH value of PATC was 7.0.Under this condition,the two kinds of coagulant effluent were characterized by three-dimensional fluorescence,and combined with the original water for quantitative analysis,the removal effect of three organic substances from the PAC was obviously improved,and the three substances were improved.It is a major component of organic pollutants in water,which are the main components of organic pollutants in water,which are rich acid,dissolved microbiological metabolites and humic acids.This also proves that PATC has a more obvious effect on decolorization than PAC.