| With the industrialization and scale of livestock and poultry industry represented by live pigs,a series of management and disposal problems have been caused along with the large number of livestock and poultry manure,and many environmental pollution problems have also been caused.On the other hand,with the rapid development of printing and dyeing,textile and other industries,the dye wastewater has great harm and needs to be treated.Using pig manure as biomass raw materials to synthesize hydrothermal carbon materials through hydrothermal carbonization reaction can not only reduce and harmless pig manure,but also remove organic dyes from wastewater by means of the rich functional groups and pore structure of hydrothermal carbon,to realize the goal of waste resource reuse.Based on this,this study used waste biomass pig manure as raw material to prepare a series of hydrothermal carbon(HC)under different temperature conditions through hydrothermal reaction,and analyzed the effect of reaction temperature on HC composition,structure,and morphology through the characterization of yield,elemental analysis,XRD,FT-IR,SEM and BET.Through the above material characterization analysis and MB preadoption experiment,the optimal structure and performance of HC were optimized.The effects of the optimal material dosage,reaction time,temperature,initial concentration of MB and solution pH value on the adsorption of MB by HC were studied through systematic static adsorption experiments.At the same time,adsorption kinetics,isothermal model and thermodynamic parameters were used to calculate and analyze the adsorption process.The adsorption mechanism was studied by solid sample analysis before and after the reaction.Finally,the actual removal capacity of HC to MB was evaluated by simulating actual wastewater,ion interference and recycling experiments.Relevant research results are as follows:(1)Through the characterization of samples at different reaction temperatures and the results of MB preadoption experiment,160℃ was revealed to be the best hydrothermal reaction condition.At 160℃,the original pig manure was dehydrated and decarboxylated to form hydrothermal charcoal with rough surface and rich pore structure.Its surface contained a variety of oxygen-containing functional groups(C-O,C=O)accompanied by aromatic structure.(2)Systematic static adsorption experiments were carried out to study the influence of factors such as dosage,reaction time,temperature,initial concentration of MB and solution pH value on the adsorption of MB by HC-160.The results show that when the dosage is 1.0 g/L,the temperature is 25℃,and the initial concentration of MB is 50 mg·L-1,the adsorption process of HC-160 can reach the equilibrium within 2 hours,and the maximum adsorption capacity is 42.6 mg·g-1.pH value has little effect on the adsorption process,and the removal rate remains high in the range of pH 3-11(>82%).Kinetic and isothermal model fitting indicated that the adsorption process of MB by HC-160 was consistent with the quasi-second-order kinetic model and Langmuir model,that is,the adsorption process was mainly the chemisorption of monolayer.Thermodynamic calculation shows that the adsorption process is spontaneous and exothermic.(3)The removal mechanism of MB by HC-160 was analyzed by comparing various solid samples before and after the reaction.The results can be summarized as follows:the removal mechanism of MB by HC-160 includes electrostatic effect and adsorption of MB through pore filling;In addition,π-π and p-π conjugation effects exist during the adsorption of MB by HC-160.(4)HC-160 shows good practical application in MB removal.It was found that the removal rate remained above 85%through 5 cycles of regeneration experiments.In MB solution containing several common ions and simulated MB water body,HC-160 can achieve efficient removal of MB.The results show that HC-160 has excellent stability and anti-interference ability,and is a potential MB adsorbent. |
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