| The remaining land application of slud ge is one of the methods of sludge treatment and disposal at present the most suitable for C hina’s national conditions. The remaining sludge in land use, would itself contains toxic heavy metals in soil and groundwater caused secondary pollution, Tondo food chain will cause damage to the flora and fauna, On the other hand sludge contains a lot of minerals(nitrogen, phosphorus, potassium, etc.) and organic matter, minerals and organic matter which can have fertility of soil, crops productive. So the removal of heavy metals in sludge becomes very meaningful.In this experiment, Xuzhou Guozhen sewage treatment plant sludge for the study, In different electrolytes, the cathode fluid types, the catholyte p H, voltage gradient, conditions of electrolysis time, a nd measuring the size of the current change during the experiment, p H value of the size of each area metal content, metal removal rate, to determine the optimum conditions, Experiments show that the experiment current trends are beginning experiments increased rapidly, reaching a peak, and then slowly decline as for stability, p H value increases from the anode to the cathode, After the electrolytic metal C u enrichment near the cathode, Cr(Ⅵ) in the vicinity of the anode enrichment, Under other conditions the same, adding electrolyte is potassium dihydrogen phosphate, the highest metal removal rate, The average removal rate of 84.80% Cu, Cr total removal rate was 38.80%, Cr(Ⅵ) removal rate was 90.86 percent, Catholyte buffer was added acetic acid, and maintaining the catholyte p H 7.5, the highest metal removal rates, The average removal rate of 77.15% C u., Total Cr removal rate was 50.80%. When the voltage gradient is 2V / cm, the maximum metal removal rate, The average removal rate of 83.60% C u, Cr total removal rate was 60.94%. When electrolysis time of 60 hours, the highest metal removal rate, average removal rate of 83.60% Cu, Cr total removal rate was 60.94%. It follows that the optimal conditions for electrolysis electrolyte is H2PO4, Cathode liquid acetic acid-sodium acetate buffer, p H of 7.5, the voltage gradient 2V / cm, electrification time is 60 h.PH changes measured by the experiment concluded that the closer area of the anode, p H is lower, the higher the redox potential, The experiment was co nducted to improve, 30 h after the movement of the anode electrolysis, to shorten the distance between the cathode and the anode, to maintain electrolyte liquid cathode type and p H, constant voltage gradient, and then electrolysis 30 h, The results show that Cu removal rate and fixed anode improved 10%, Zn removal rate increased by 24%.The experimental results, in a certain range, with the greater the applied voltage gradient, the higher metal removal rate, But the voltage gradient is too large, prone to polarization, The reaction of hydrogen evolution voltage voltage magnitude of the polarization phenomenon, After the addition of heptane and cyclohexane organic liquid in the cathode, hydrogen evolution voltage is changed, From 1.42 v / cm into 0.667 v / cm, To Zn removal, for example, Removal from the 60.94 percent rise to 83.70%. Adjust the voltage during the test, so that the cathode is not always bubbles, It can also reduce the polarization, C u metal removal rate increased from 83.6% to 89.78%. Zn metal removal rate increased from 60.94% to 75.36%. |
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