Experimental Research On Microwave Chemical Leaching Removal Of Heavy Metals In Municipal Sewage Sludge

In this paper,based on the research results of the previous research group,we optimized the microwave chemical leaching recipe,determined the optimum operating conditions of heavy metal capture agent M for removal of heavy metals in chemical leaching and the number of chemical leaching cycles,which provides data support for the leaching of heavy metals in municipal sludge.The results show:(1)The orthogonal experiments were carried out by tartaric acid dosing and different single-factor experiments for different heavy metals.The optimal formula for microwave chemical leaching was 4.2mL PESA,1.8mL EDDS,3.0mL H2O2,4.5mL tartaric acid and 2mL CTA,while the average removal rate of five kinds of heavy metals in mud is more than 86%.(2)The optimal conditions for heavy metal capture agent M to treat heavy metals in acid leaching solution were determined as follows:adding the volume of 10%heavy metal capture agent M-2 is 4.0 mL at room temperature,90 s at 260 r/min,adding the volume of 1g/L PAM is 3.0 mL,the stirring speed was 40 r/min for 10min and the reaction time is 40min,the removal rate of Cu2+,Zn2+,Pb2+,Cd2+and Ni2+were 73.24%,63.77%,64.28%,57.58%and 54.22%respectively.Comparing the maximum leaching quantity experiment of the heavy metal capture agent M-2 capture products and the NaOH neutralize products,it is found that the former has an advantage,a significant reduction of the possibility of re-pollution.(3)The optimal cycle number of acid leaching solution was 5 times by the content of heavy metals in the sludge.Comparing all forms of heavy metals,TN,TP,TK and organic matter in microwave chemical leaching with after 5 cycles of acid leaching was found that all forms of heavy metals changed little,the content of TN increased,the content of TP and TK decreased slightly,so the sludge could still be used in land use.Considering the removal rate of heavy metal capture agent M-2 by trapping after acid leaching cycle of various heavy metals after 5 times,so the optimal cycle number of acid pickling solution after trapping was determined as 4 times.Figures 18,Tables 19,References 79.