Preparation Of M_xO_y/C Composites And Its Application In Phenol Wastewater Treatment

Phenolic wastewater,a kind of organic refractory wastewater containing phenol and other chemical toxicants,which has great harm to human health and social environment.It is an important source of environmental water pollution.It has the characteristics of strong toxicity,carcinogenicity,mutagenicity and wide range of pollution.Therefore,efficient treatment of phenolic wastewater is imminent.Carbon-loaded activated manganese oxides?Mn_xO_y/C?or Fe⁰/C nanocomposites have potential industrial application value in the treatment of organic wastewater.Therefore,the efficient treatment technology of phenolic wastewater has become a research hotspot of many researchers.Mn_xO_y/C has a high-potential manganese active component and a rich microporous structure.It has good conductivity and reactive sites and is a desirable material for the efficient treatment of phenol-containing wastewater,but it is rarely used in the treatment of p-nitrophenol wastewater.In this paper,Mn_xO_y/C and Fe⁰/C nanocomposites were prepared by isothermal impregnation method using biomass carbon as carrier.The materials were characterized by XRD,TEM,nitrogen adsorption and desorption,and the reaction conditions such as reaction temperature and time were studied.The effect of composite material treatment on the performance of simulated organic wastewater was studied.Combined with the test results,the mechanism of material composition,structure and texture of materials on the treatment of organic wastewater was discussed.The specific research content includes the following aspects:?1?The manganese material was used as the active component precursor,the carbon material prepared by bio-fermentation and high-temperature roasting technology was used as the carrier,and the Mn_xO_y/C nanocomposite was prepared by the excess impregnation combined with the aerobic high-temperature carbon thermal reduction.The optimized preparation condition of Mn_xO_y/C was the calcination temperature is 400 °C and the calcination time is 120 min.The treatment performance of p-nitrophenol wastewater is investigated.At the reaction temperature of 40 °C,the dosage of 9% Mn_xO_y/C is 1.0 g?manganese content is 9%?,and the reaction time is 100 min,the removal rate of p-nitrophenol in simulated wastewater was 90%.According to the characterization of Mn_xO_y/C,Mn_xO_y/C mainly exists in the valence state of +3,+4 such as Mn₂O₃,Mn₃O₄,MnO₂,etc.the main crystal form is tetragonal crystal,which has mesoporous morphology and pore structure,the pore size of the material and The specific surface areas were 5.6 nm and 325.6 m²/g respectively.The 9% Mn_xO_y/C removal of p-nitrophenol simulated wastewater accords with the Langmuir adsorption model and belongs to single-layer adsorption.The quasi-secondary kinetic model can better fit the removal process.Adsorption thermodynamics showed that 9% Mn_xO_y/C removed p-nitrophenol wastewater as a self-heating reaction.?2?The carbon material prepared by ferric nitrate nonahydrate as active component,bio-fermentation and high-temperature roasting technology is used as carrier,and Fe⁰/C nanocomposite is prepared by excess impregnation combined with high temperature and oxygen-limited carbon thermal reduction.The optimal preparation conditions are: iron The content is 20%,the calcination temperature is 900 °C,and the calcination time is 120 min,the performance in the treatment of p-nitrophenol wastewater is investigated.At a treatment temperature of 40 °C,the time is 60 min,the dosage of 20% Fe⁰/C is 1.5 g,the degradation rate of p-nitrophenol can reach 98%.Through the analysis of Fe⁰/C performance,the biomass carbon material is a multi-layer carbon structure,and the iron mainly exists in the 101 crystal plane of Fe⁰.The introduction of iron is beneficial to the increase of the pore diameter of the carbon material,and the material mainly exists in the form of mesopores;The process of treating p-nitrophenol in wastewater by 20% Fe⁰/C nanocomposite conforms to the quasi-secondary kinetics process;the isothermal adsorption model conforms to the Langmuir adsorption mode of monolayer adsorption.?3?The Fe⁰/C nanocomposites were selected as three-dimensional filler particles,and the performance of Fe⁰/C treatment of p-nitrophenol simulated wastewater under electrocatalytic conditions,which was further studied.With the anode of BDD electrode and the cathode of stainless steel electrode,the degradation rate of 5 g Fe⁰/C can still reach above 60% in the 100 m L wastewater solution with a voltage of 14 V and an electrolyte solution concentration of 10 g/L after repeated 8 times.By comparing the degradation effects of Fe⁰/C and Mn_xO_y/C on the simulated wastewater with different concentrations of p-nitrophenol,the results showed that Fe⁰/C nanocomposites have higher reactivity potential energy and stability.