Study On The Adsorption Of Landfill Leachate By Sludge-straw Based Activated Carbon

The utilization of municipal sludge and biomass straw is one of the hot topics in the field of resources and environment.Therefore,this paper prepared activated carbon?ACs?by municipal sludge?SS?and corn straw?CS?,while the potassium carbonate as activator.The optimum AC was applied to the adsorption experiment of landfill leachate,and its adsorption characteristics for leachate COD and dissolved organic matter?DOM?were explored.The main content and conclusions are as follows:1.Using orthogonal experimental method,the optimum conditions for the preparation of sludge-straw-based activated carbon were determined:raw material dry basis ratio was 3:7:0.25(W_SS:W_CS:W_K2CO3),the carbonization temperature was 750°C and the time was 0.5h.The average yield of activated carbon was 45.81%,the average iodine adsorption value was 517.43 mg/g,and the average specific surface area was 675.30 m²/g.2.The results of SEM and BET characterization showed that,the main pore structure of sludge-straw-based activated carbon is microporous,micropore volume accounts for75.96%of the total pore volume,and the average pore size is 2.467 nm.Potassium carbonate can reduce the activation energy of the sample to some extent,it helps to decompose the material in the carbonization process,and enlarge the pore volume inside the activated carbon.3.The results of adsorption experiments show that,when the dosage of activated carbon is 36g/L,adsorption for four hours at pH 10,40°C,the removal rate of COD by activated carbon is the best.Under the optimal conditions,the removal rates of COD and NH₃-N and DOC of leachate are 72.06%and 72.81%and 82.91%.The removal efficiency of activated carbon on all indexes of leachate is stronger than that of market activated carbon.At the same time,fitting Langmuir and Freundlich isothermal equation,the adsorption of COD in the leachate by activated carbon was multi-layer adsorption.4.The results of three dimensional fluorescence spectrum analysis show that,after the adsorption of sludge-straw-based activated carbon,the relative fluorescence content of I and II?tyrosine and tryptophan?increased in the three dimensional fluorescence spectra of leachate,and the fluorescence intensity was also increased.The relative concentration of fluorescence peaks in V region?Hu Min acid?decreased,the fluorescence intensity was also reduced.The total volume of the total fluorescence area after activated carbon adsorption was larger than that before adsorption,indicating that the total amount of fluorescent substances in leachate increased after adsorption of activated carbon.5.According to the GC-MS analysis,the organic matter of leachate changed greatly before and after adsorption.There are 23 kinds of substances with the removal rate of organic matter above 50%in the leachate after the adsorption of sludge-straw-based activated carbon,the results showed that sludge straw based activated carbon had good adsorption effect on most organic matters in leachate,it is suitable for the early treatment of leachate.