Glyphosate Waste Salt Membrane Separation And Phosphorus Removal Process And Its Comprehensive Equipment Design

Glyphosate,as a broad-spectrum,insecticidal herbicide,is widely used in China’s agricultural production.Glycine method,as the main way to produce glyphosate in China,will produce a large amount of by-product waste salt containing total phosphorus and total organic carbon,which will cause waste of resources and damage to the environment if left untreated.Therefore,we adopt membrane separation method to pretreat glyphosate waste brine and link chlor-alkali industry through phosphorus removal and debris removal resin adsorption to achieve green production.For this reason,this thesis revolves around the study of glyphosate phosphorus removal and debris removal,using membrane separation method to reduce the total phosphorus content in glyphosate preliminary purification brine,which greatly traps the total phosphorus and reduces the pressure of precipitation and phosphorus removal.Designing10,000 tons of waste salt membrane separation to remove phosphorus and debris deep purification process,exploring the influence of impurity ions on the ion membrane electrolysis process,analyzing the ion membrane surface scaling and fouling using SEM and EDS,and preparing the technical specification of modified concave clay,the main research results are shown as follows.The glyphosate waste salt was calcined at 550℃to obtain glyphosate preliminary purification salt containing inorganic phosphorus.The initial p H was set at 10 and the concentration of 330 g/L of glyphosate preliminary purified salt solution was separated by secondary membranes.The experimental results showed that the ultrafiltration membrane retained a molecular weight of 5000 Da,and the applied pressure was 0.4 MPa.With a MWCO of 150 Da and an applied pressure of 2.6 MPa,the NF membrane flux could reach 210 L/m²·h,the Na Cl removal rate was 46%and the total phosphorus removal rate was 96%.The effect of impurity ions on tank current,current density,p H and conductivity during ion membrane electrolysis was investigated by using cation exchange membrane to electrolyze sodium chloride solution with impurities Ca²⁺and Mg²⁺,and the effect of precipitation of magnesium hydroxide and calcium hydroxide formed by impurity ions on ion membrane surface and pore channel was also investigated.SEM&EDS showed that the precipitation formed by impurity ions will deposit on the surface of ion membrane and block the pore channel of ion membrane,which will accelerate the rate of current density rise during electrolysis and cause electrolysis accidents and shorten the service life of ion membrane.A 10,000-ton membrane adsorption separation and deep phosphorus removal and debris removal project was designed for 300 days of annual operation,24 hours of daily operation,4.63 m³ of preliminary purified salt solution per hour,initial p H=10,and initial concentration of 300 kg/m³,using glyphosate preliminary purified salt as the raw material solution.The process flow is:secondary membrane separation-precipitation and phosphorus removal-resin adsorption.The membrane elements used are selected as:American Koch TARGA II 10072-35 as separation ultrafiltration membrane,Zhongkeruiyang rolled acid and alkali resistant nanofiltration membrane S300,Jiuwugaoke microfiltration 1200,phosphorus removal agent using Jiangsu Lishui JS-305A,the dosage of 3.5 kg/m³.Chelating resin D468 was used,with a resin filling volume of 4.71 m³ and a resin filling height of 1.5 m.The literature related to the study of modified attapulgite by domestic scholars was reviewed,relevant modification experiments were verified,and various technical requirements for attapulgite after different modification methods were developed.The sieve allowance（0.08mm square pore sieve）of the modified attapulgite was divided into three levels,with the first level≤8.0,the second level≤10.0,and the third level≤15.0;the p H index was 7～9;the water content index was≤1.0 for the first level,≤1.0 for the second level,and≤2.0 for the third level;the three levels of total phosphorus adsorption capacity were≥60 mg/g for the first level,20～60 mg/g for the second level,and 10～20 mg/g for the third level.To provide guidance for the research of modified attapulgite.