Experimental Study On Preparation And Treatment Of Fluoride-Containing Arsenic Acid Wastewater By New Composite Materials

The fluorinated arsenic-containing acidic wastewater?total arsenic 2373mg/L,trivalent arsenic 1431mg/L,fluorine 487mg/L?was studied.The toxicity and solubility of trivalent arsenic are much greater than that of pentavalent arsenic.In the removal of trivalent arsenic,it is usually necessary to pre-oxidize trivalent arsenic to pentavalent arsenic.According to this development,the pre-oxidation process of coated modified ferric sulphate combined with stabilizer is developed.Precipitation flocculation process".In the preparation stage of the package,ethyl cellulose was selected as the potassium ferrate-coated material,and the optimum core-to-wall ratio was found to optimize the performance of the modified modified potassium ferrate to remove As???.In the oxidation removal stage,The package is modified with potassium ferrate and a stabilizer to oxidize trivalent arsenic.In the stage of precipitation flocculation,the arsenic and fluorine are treated by the two-stage process of“iron salt coprecipitation+flocculation and sedimentation”to make the effluent water quality reach GB.25467-2010"Copper,cobalt,nickel industrial pollutant discharge standards"requirements.This paper mainly discusses:?1?Ethylcellulose and sliced paraffin were used as primary coating agents,and K₂Fe0₄ was coated by evaporation precipitation method and suspension stirring condensation method,respectively.Ethylcellulose wrap and paraffin wrap were prepared under the conditions of core material to wall ratio of 1:2 and optimum encapsulation rate.The release rate and the ability to oxidize trivalent arsenic were compared.Ethyl fiber The rate of release of the encapsulated product and the efficiency of oxidative removal of trivalent arsenic were 96.23%and 86.24%,respectively,which were higher than that of paraffin inclusions and 79.12%and63.61%of trivalent arsenic.The final choice was ethyl cellulose as ferric acid.Potassium wall covering.?2?Using ethyl cellulose as the wall material,the effect of the ratio of core material to wall material on the modification of As???oxidized by potassium ferrate was investigated,and the core material and wall with the best ability to oxidize As???were selected.The ratio of material to 1:2.5,at p H=5,the removal rate of As???by modified K₂Fe0₄ was 86.24%,and the removal rate of As???by uncoated K₂Fe0₄was increased by 6.6%.According to the particle size,IR and SEM,ethylcellulose was coated on the surface of potassium ferrate,which did not destroy the active component of potassium ferrate.At the same time,the surface of the coated modified potassium ferrate had a certain void structure to satisfy the high potassium ferrite.The conditions of release.Its release tendency in water is consistent with the In?1-Mt/M??=-Kt first-order kinetic model.?3?Selecting the core material to the wall material ratio 1:2.5 wrapped modified potassium ferrate,in M?package modified potassium ferrate,the amount of potassium ferrate contained in it?/M?As????1 At 1:1,the effect of p H on the oxidation of trivalent arsenic by modification of potassium ferrate and potassium ferrate was investigated.At p H=4,the efficiency of oxidation of trivalent arsenic by modification of potassium ferrate was 84.3%.At p H=5,the highest value of 73.2%was obtained by the oxidation of uncoated high potassium ferrite to remove trivalent arsenic,indicating that the modified modified ferric acid potassium oxidized As???was better,and the removal rate peak shifted to the left.There is also a good oxidative removal rate under the conditions.In the case of M?package modified potassium ferrate,the amount of potassium ferrate contained in it?/M?As????is 1:1,p H=5,the temperature is 25°C,the investigation of sodium silicate stabilizer The effect of oxidation on the removal of As???by modified ferric potassium ferrite was added.When the dosage of stabilizer was 0.05mol/L,the efficiency of As???removal by modified potassium ferrate was 95.2%.84.3%of the dose was 10.9%higher.By orthogonal experiment,at p H=4,M?package modified potassium ferrate,the amount of potassium ferrate contained therein?/M?As????=1.2:1,stabilizer=0.05 mol/L,As???in wastewater can be reduced from 1431 mg/L to 2.86 mg/L.?4?For the pre-oxidation of fluorine-containing arsenic-containing tail acid,the method of"iron salt coprecipitation+flocculation precipitation"is adopted,and the first stage is added with 12.0 g/L of polyferric sulfate to control p H=6.0;0.8 g/L of polymeric ferric sulfate was added to control p H=6.0,and finally 3 mg/L of PAM and0.3 g/L of PAC were charged.After treatment,the fluoride ion concentration in the fluorine-containing arsenic-containing tail acid decreased to 9.63 mg/L,the arsenic ion concentration decreased to 0.3 mg/L,and the effluent water quality stabilized to meet the GB 25467-2010"copper,cobalt,nickel industrial pollutant emissions Standards requirements.