Preparation Of Polysilicate Based Inorganic Polymer Composite Flocculant And Its Application In Water Treatment

With the economic development and the progress of human civilization and society,higher demands are placed on water treatment.We have developed new inorganic polymer composite flocculants polysilicon ferric titanium sulfate(PTFS)and polysilicon titanium aluminum sulfate based on polysilicate,iron salt,aluminum salt and environmentally friendly "biophilic metal" titanium salt(PTAS),it is expected to obtain a flocculant that has a wider application range,higher processing efficiency,and safe and healthy adaptation to people's higher requirements for water treatment compared with traditional inorganic flocculants.Firstly,the optimal raw material ratio of the flocculant was determined through the screening test of removing turbidity and phosphorus,and then the surface morphology and structure of the flocculant were characterized by scanning electron microscopy and infrared spectroscopy.The fractal dimension and Zeta potential were used.Initially explored the flocculation mechanism of PTFS and PTAS,and through single factor test,orthogonal test,response surface test to explore the flocculant dosage concentration,pH value,fast stirring time,slow stirring time,standing time and other factors on the flocculant The influence of the effect of turbidity removal and phosphorus removal and the interaction between various factors have determined the optimal flocculation process conditions.The main conclusions are as follows:(1)Through the screening test of turbidity and phosphorus removal of flocculants with different raw material ratios,the best ratio of PTFS flocculants is determined as n(Ti + Fe): n(Si)= 1: 4,n(Ti): n(Fe)= 1: 5;PTAS The best ratio of flocculant is n(Ti + Al): n(Si)= 1: 4,n(Ti): n(Al)= 5: 1.(2)According to scanning electron microscopy and infrared spectroscopy,when titanium ions,iron ions,and aluminum ions are added,the external morphology and internal structure of the polysilicic acid flocculant change significantly.PTFS flocculant and PTAS flocculant have the formation of Si-O-Ti,Si-O-Fe,Si-O-Al,Ti-O chemical bonds,respectively.(3)According to the results of fractal dimension and Zeta potential combined with scanning electron microscopy and infrared spectroscopy analysis,the mechanism of turbidity and phosphorus removal of PTFS and PTAS flocculants is not just simple chemical precipitation,surface hydroxyl adsorption,net trapping sweep,adsorption Bridging and electrical neutralization have played an important role.(4)The order of PTAS flocculant's turbidity removal rate is affected by five factors: standing time> fast stirring time> slow stirring time> pH> flocculating agent concentration Among them,the interaction between pH and standing time,fast stirring time and standing time is significant,and the standing time and fast stirring time are the key factors affecting the turbidity removal rate,and the best condition for PTAS turbidity removal is the flocculant concentration 0.6mmol / L,pH = 7,faststirring(180 r / min)time is 4 min,slow stirring(30 r / min)time is 40 min,and standing time is 120 min.The order of PTAS on phosphorus removal rate is affected by five factors: pH> flocculant concentration> fast stirring time> standing time> slow stirring time.In the response surface test,the interaction between the concentration of flocculant and pH is significant.The pH and the concentration of flocculant are the key factors affecting the removal rate of phosphorus;and the optimal condition for the removal of phosphorus by polysilicate titanium aluminum sulfate is the concentration of flocculant at 0.05 mmol / L,pH = 10.5,fast stirring(180 r / min)time is 3 min,slow stirring(30 r / min)time is 50 min,and standing time is 60 min.(5)The removal rate of turbidity by PTFS flocculant is affected by five factors.The order of magnitude is: slow agitation time> standing time> slow agitation speed>pH> flocculant dosing concentration;pH value and standing time,slow The interaction between stirring time and standing time is significant;the best flocculation conditions are: the dosage of flocculant concentration is 0.60 mmol / L,pH = 10.0,fast stirring(180 r / min)time is 4 min,slow stirring(30 r / min)The time is 30 minutes and the standing time is 120 minutes.The order of PTFS's phosphorus removal rate is affected by five factors: standing time> pH value> flocculating agent concentration>slow stirring time> fast stirring time,in which the flocculant dosage concentration,pH value,and standing time are three The interaction between the two is significant;the best conditions for PTFS dephosphorization are: the dosage of PTFS flocculant is0.1mmol / L,the pH is 10.5,the rapid stirring(180 r / min)time is 2 min,and the slow stirring(30 r / min)The time is 20 minutes,and the standing time is 90 minutes.