Optimum Conditions For Activated Carbon From Sewage Sludge By Microwave

The sewage sludge of urban sewage treatment plant in China has increased year by year.In 2015,the production of sludge in China has reached 35 million T,and it continues to increase.The traditional sludge disposal methods,such as landfill,incineration,composting and so on,cause two times of pollution to the environment,which can no longer meet the needs of environmental protection.Seeking new sludge disposal methods has become an urgent problem.In recent years,a lot of scholars have done a lot of research on the preparation of activated carbon from sludge.However,most of the old thermal resistor heating methods have the advantages of high energy consumption,low efficiency and low yield.Compared with the traditional heat source,the microwave heat source has the advantages of high energy efficiency,fast heating,uniform heating and low energy consumption,which can save a lot of time and energy.In this study,the dehydrated sludge of a sewage treatment plant in Xi'an was used as the material,ZnCl₂ and K₂CO₃ were used as activators,and microwave was used as the heat source to produce the activated carbon.Using the orthogonal experiment,it is proved that the properties of the activated carbon that obtained by the ZnCl₂ are similar whether through the microwave heat source or the traditional heat source.And through full factorial screening of K₂CO₃ as agent for the preparation of activated carbon activated clay,the prominent influencing factors,screening out the main factors,with the central composite design?CCD?and Response Surface Methodology?RSM?,analysis the main factors and their interactions,fitting of quadratic equation,the optimum conditions for preparation of K₂CO₃ activator for mud activated carbon.Finally,the clay activated carbon prepared by the K₂CO₃ activation method was used to treat the adsorption of simulated aniline wastewater and ionic liquid,and the properties of the activated carbon were tested.In order to obtain the rate and iodine value as the index,ZnCl₂ activator preparation mud of activated carbon by orthogonal test and single factor experiment,the optimum conditions?microwave power 700W,irradiation time 20min,activator concentration 3mol/L,liquid-solid ratio 2.5:1?,under this condition,the quality of activated carbon prepared by the rate of mud 29.34%,the iodine value was 363.74mg/g.K₂CO₃ activator preparation mud of activated carbon by full factorial design using CCD screening,response surface analysis and optimization,the gain rate?H₃?quadraticequationfor₃=78.50-0.1619(3₁-1.860(3₂+13.73(3₃+0.000102(3₁²+0.04255(3₂²-2.216(3₃²+0.0007(3₁(3₂+0.0028;the iodine value?Z₃?of the quadratic equation:(5₃=-383.8+2.824(3₁-16.13(3₂-3.318(3₃-0.00227(3₁²+0.504(3₂².Results:in solving parameters for microwave power 600W and irradiation time of 20 minutes,the concentration of the activator 3.1010mol/L can be obtained when the maximum value of 32.8774%362.0617 mg/g and the rate of iodine.The process parameters for microwave power 600W and irradiation time of 20minutes,the concentration of the activator 3.1mol/L,liquid-solid ratio is 2.5:1,the preparation of K₂CO₃ mud activated carbon,and measured the yield and iodine value is 32.9454%and 364.421 mg/g,consistent with the predicted.The use of K₂CO₃ activator preparation process of activated carbon mud of aniline wastewater and ionic liquid adsorption,to test its adsorption performance over the same carbon amount,adsorption time,pH value,initial concentration of four indicators to examine the effect of mud activated carbon treatment of aniline and ionic liquid.The results showed that the removal of the optimal combination of factors is the rate of the activated carbon dosage 1 g?2 g activated carbon/mg aniline?,adsorption time 180 min,initial concentration of aniline solution 10 mg/L,pH value is 4,the removal rate reached97.21%;the optimal combination of factors and the adsorption capacity of activated carbon dosage of 0.5 g?1 g activity carbon/mg aniline?,adsorption time 180 min,initial concentration of aniline solution 10 mg/L,pH value is 7,the adsorption capacity reached 0.9663 mg/g.The best conditions for the adsorption of ionic liquids are:the initial concentration of[Bmim]CL solution is 80 mg/L,pH=6,the dosage of activated carbon 100 mg,namely 25 mg/mg[Bmim]CL,the reaction time is 60min,under this condition,the removal rate of[Bmim]CL can reach 92.85%.