Study Of The Adsorption Performance Of Methylene Blue And Aniline On Edible Fungi Residues Activated Carbon

Methylene blue（MB）and aniline are widely used in printing,dyeing,electroplating,tanning and other related industries.As a result,a large amount of MB and aniline-containing waste water was generated,discharged into environment,which can cause allergies,skin irritation and even carcinogenesis,endanger human health,causes serious harm to environment.At present,the main methods for treating MB and aniline-containing wastewater are biodegradable,chemical oxidation,coagulation,membrane filtration and adsorption.Among them,the adsorption was considered to be an effective method for treating MB and aniline organic wastewater due to its simple operation,recyclability,and economic efficiency.The existing adsorption materials have problems such as high cost and low adsorption capacity.Therefore,the preparation of economical materials with high adsorption performance is very important for the treatment of MB and aniline-containing organic wastewater.Edible fungi residues（EF）are by-product of edible fungi.China’s annual output exceeds13 million tons.Most of the EF were discarded or incinerated,causing serious environmental pollution.The main components of EF are wood chips and cottonseed hulls,which have a loose structure with multi-dimensional framework.In this study,EF was used as a low-cost precursor to prepare edible fungi residues activated carbon（EFAC）and manganese-loaded modified edible fungi residues activated carbon（Mn-EFAC）.Realize the high-value resource utilization of waste,and achieve the effect of"using waste to treat waste".The main research contents and results were as follows:1.EFAC removed MB in water.When the MB concentration was 100 mg/L and the EFAC dosage was 0.4 g/L,the MB concentration in the effluent was 0.68 mg/L,and the removal rate is as high as 99.32%.The study of static adsorption thermodynamics and kinetics shows that the adsorption process conforms to pseudo-second-order kinetics,and the adsorption equilibrium is reached quickly after 40 minutes of reaction.The Langmuir adsorption isotherm model better represents the adsorption process of MB on EFAC,and the maximum adsorption capacity obtained is 666.67 mg/g.After the saturated EFAC is subjected to three adsorption-regeneration cycles of ethanol,hydrochloric acid and sodium hydroxide,the removal rate of MB by EFAC is 76.19%,75.21%and 62.53%of the original EFAC,respectively.The surface of EFAC has a loose and porous structure.The adsorption mechanism was discussed based on characterization analysis.MB is adsorbed on the EFAC through electrostatic interaction,hydrogen bond,π-πinteraction and van der Waals force.2.EFAC removed aniline in water.When the aniline concentration was 10 mg/L and the dosage was 4 g/L,the aniline concentration in the effluent was 2.28 mg/L,and the removal rate is 77.16%.The study of static adsorption thermodynamics and kinetics shows that the adsorption process conforms to pseudo-second-order kinetics,and the adsorption equilibrium is reached after 18 hours of reaction.The Langmuir adsorption isotherm model better represents the adsorption process of MB on EFAC,and the maximum adsorption capacity obtained is12.87 mg/g.After the saturated EFAC is subjected to three adsorption-regeneration cycles of ethanol,hydrochloric acid and sodium hydroxide,the removal rate of aniline by EFAC is81.47%,76.87%and 67.39%of the original EFAC,respectively.Combined with characterization analysis,it was determined that aniline was adsorbed and removed through electrostatic interaction,hydrogen bond,π-πinteraction and van der Waals force.3.Using KMnO₄ modification to prepare the Mn-EFAC,and compared the adsorption performance of aniline before and after modification.The concentration of aniline was 10 mg/L,the effluent concentration of aniline was 0.03 mg/L,when the dosage was 4 g/L,and the removal rate is 99.70%.After the saturated Mn-EFAC is subjected to three adsorption-regeneration cycles of ethanol,hydrochloric acid and sodium hydroxide,the removal rate of aniline by Mn-EFAC was 77.46%,78.50%and 69.41%of the original Mn-EFAC,respectively.The specific surface area of Mn-EFAC was 1487 m²/g,and the number of oxygen-containing functional groups increased.The adsorption process conforms to the pseudo-second-order kinetics,and the adsorption equilibrium is reached within 3 h.The Freundlich adsorption isotherm model better represents the adsorption process of aniline on Mn-EFAC.The total organic carbon（TOC）removal rate is 88.90%.Manganese oxide has two functions:adsorption and oxidation on Mn-EFAC.Using GC-MS to determine the reaction intermediate product,aniline is partially oxidized to hydrolyzate and self-coupling products.It is further adsorbed by electrostatic interaction,hydrogen bond,π-πinteraction,van der Waals force and active groups.4.The fixed bed adsorption experiments of EFAC and Mn-EFAC for MB and aniline respectively show that the best conditions for fixed bed adsorption:low influent concentration,low flow rate,and high bed height.The BDST model and Thomas model can be used to describe the dynamic adsorption of EFAC and Mn-EFAC to MB and aniline.Yoon-Nelson model can not represent the dynamic adsorption process of MB and aniline by EFAC and Mn-EFAC.