Preparation Of Cement-based Electrocoagulation Electrode Plates And Its Research On The Removal Of Heavy Metal Ions From Water Bodies

In recent years,with the accelerated industrialization,a large amount of industrial wastewater and urban domestic wastewater containing heavy metals have been discharged into the environment,causing extremely serious impacts on the atmosphere,soil and water environment.It has become an urgent environmental problem to treat heavy metal wastewater in an environmentally friendly way.Electrocoagulation,as an environmentally friendly and efficient technology for treating heavy metal wastewater,is gaining popularity.However,the high cost limits the development of electrocoagulation.Therefore,this paper considers the combination of conductive cement-based materials and electrocoagulation technology,which can effectively reduce the cost of electrocoagulation and make this environmental technology more widely used.In this paper,we developed a cement-based electrode plate that can be used as an electrocoagulation cathode.Carbon fiber and carbon black were chosen as the conductive filler for the plate and the percolation threshold was determined to be 1.5 wt%and 5 wt%respectively.The best performance of the conductive cement-based pole plate was determined at a water to ash ratio of 0.55.The resistivity of the produced cement-based pole plate was 122.4Ω·cm,the average compressive strength was 27.3 MPa and the flexural strength was 29.09 MPa,showing good mechanical properties.The electrode plate was used for the treatment of wastewater containing heavy metals Cu and Ni in electrocoagulation technology.The effects of current density,initial concentration of heavy metal ions,plate spacing,addition of conductive salt Na Cl and stirring speed on the removal efficiency of heavy metals were investigated,and the optimum conditions for the removal of Cu²⁺in an electrocoagulation system with a conductive cement-based plate as the cathode were determined as follows:current density of 8 m A/cm~2,initial concentration of Cu²⁺The optimum conditions for the removal of Cu²⁺were:current density of 8 m A/cm~2,initial Cu²⁺concentration of 200 ppm,electrode plate spacing of 1 cm,Na Cl addition of 0.01 mol and magnetic stirring speed of 250 rpm.99.7%removal of 1 L of Cu²⁺containing wastewater could be effectively achieved within 60 min under the above conditions,the dissolved amount of aluminium anode was about 0.268 g and the electrical energy consumption was about 7.043KWh/m~3.The optimum conditions for the removal of Ni²⁺were.The current density was 14m A/cm~2,the initial concentration of Ni²⁺was 50 ppm,the spacing between the electrode plates was 1 cm,the amount of Na Cl added was 0.01 mol,and the magnet stirring speed was 250 rpm.Under these conditions,the removal rate of 1L of Ni²⁺containing wastewater was 84.5%within60 min,the dissolved amount of aluminium anode was about 0.470 g,and the electrical energy consumption was about 24.001 KWh/m~3.The cost of removal was also evaluated and the mechanism of electrocoagulation was elucidated to some extent.The conductive cement-based electrode plates have been subjected to electrocoagulation tests and have been confirmed to be reusable and functionally stable through floc analysis,surface micromorphology observations and energy spectroscopy and reusability tests.