PMS Oxidation-electroflocculation Treatment Of Manganese-containing Wastewater

Manganese is an essential auxiliary element for the synthesis of many enzymes in the human body.However,experiments have shown that excessive amounts of manganese can adversely affect the nerves,reproduction and respiration of animals and humans.As one of the important testing indicators of environmental water quality pollutants,it is required to be able to meet the discharge standards.Manganese-containing wastewater has a wide range of sources.A large amount of leaching water,pit gushing,interception and drainage generated during the mining of manganese ore,beneficiation and smelting wastewater pose a serious threat to the environment.Most companies use alkaline solution precipitation and coagulation methods,but chemical precipitation may induce secondary pollution caused by the addition of chemical substances,and the removal efficiency is low.In recent years,the treatment of heavy metal wastewater by electro-flocculation has attracted widespread attention at home and abroad.This paper mainly studies the optimization of the treatment parameters for the removal of simulated manganese-containing wastewater by using advanced oxidation-electro-flocculation method using potassium peroxymonosulfate(PMS,KHSO₅)as the oxidizing oxidant.Explore the mechanism of electro-flocculation,the influence of sulfate and chloride ions,the influence of calcium and magnesium ions.The main conclusions are as follows:For simulated manganese-containing wastewater,the removal of manganese ions is greatly increased by increasing the amount of PMS,and it can achieve a good removal effect for both low-concentration and high-concentration manganese-containing wastewater.The base SO₄^·-manganese oxide ions form Mn O₂·H₂O precipitates.Aluminum and iron plates are used as electrode plates.For the PMS-electro-flocculation oxidation reaction system(EC/PMS),it is found that aluminum plates have better removal effects than iron plates,and the Zata potential of the flocs is closer to the zero potential point The rear supernatant is clear and free of impurities;the iron plate has severely inhibited the removal of Mn²⁺due to the competitive relationship between Fe²⁺produced by the electrolytic anode and Mn²⁺.For the precipitates obtained by Al-Al EC/PMS treatment,researches by modern analysis and testing methods such as XRD,FT-IR,XPS,and SEM show that the flocs are generally amorphous and the manganese compounds produced are mainly Mn O₂.FT-IR analysis showed that the floes had structural layers and the water molecules between the layers produced O-H stretching peaks,symmetrically stretched SO₄^2–vibrations and their O-S-O bending vibration peaks.By SEM analysis,there are both amorphous flocs and the internal lamellar structure after grinding and damage.XPS analysis of aluminum products is mainly Al(SO₄)(OH)·5(H₂O),the content is about 80.58%.The removal of manganese is mainly due to the activation of PMS by e^–and Mn O₂ to oxidize Mn²⁺to Mn O₂.When using aluminum as the polar plate(Al-Al EC/PMS system),the wastewater containing Zn²⁺and Mg²⁺alone and the mixed wastewater of Zn²⁺and Mn²⁺,Mg²⁺and Mn²⁺,whether PMS is added,has no effect on the removal of Zn²⁺,Mg²⁺and Mn²⁺However,the presence of Mn²⁺has a significant effect on the removal of Zn²⁺and Mg²⁺;this is because Zn²⁺and Mg²⁺are already the highest valence states of the corresponding metals,and Mn²⁺is removed by oxidation,but co-precipitation of metal ions will occur in the mixed system.In addition,the moderate concentration of Cl^–is conducive to the removal of manganese,and SO₄^2–with Mg²⁺,Ca²⁺,and excessively high concentrations of Cl^–all have a detrimental effect on the removal of manganese.Among them,SO₄^2–inhibiting the removal of manganese is mainly because SO₄^2–inhibits SO₄^·-The oxidation of manganese ions hinders the conversion of manganese ions into Mn O₂·H₂O precipitates.The actual manganese-zinc leaching wastewater research results show that the Al-Al EC/PMS treatment process is used,the addition current density is 16 m A·cm^–2,the initial p H value is 6,PMS=6 mmol·L^–1,Na₂SO₄=Under the condition of 10 mmol·L^–1,the treated wastewater containing heavy metal ions such as Zn²⁺,Mn²⁺,and Fe²⁺can meet the discharge standards of the emission standard of Class A of"Emission Standard of Pollutants for Urban Sewage Treatment Station"(GB 18918-2002).