Study On CO₂ Hydrothermal Reaction To High-valued Organic Acid With Waste Cans

In recent decades,technology rapidly develops and people's living consumption level increases linearly.For meeting greed need,Nature which gets on well with human beings,has been the target of massive destructive behavior.Due to the growth of fossil fuel consumption as well as greenhouse gas emission,like CO₂,which makes people pay more and more attention to climate change.Fossil fuels provide almost 80 percent of business energy supplement,which suggests the concertation of greenhouse gas accumulating.This phenomenon is considered to cause dramatic change of climate,and lead to serious economic and social impact.Thus,a convenient,high-efficient and low-cost CO₂ treatment method is to be urgently exploreed to relieve environmental risks in the moment and future.Since human enter the 21^st century,a variety of soft and canned drinks are put into the markets,to meet people's need.However,there are still no good ways treating them,so it caused enormous waste and can to pipe up,polluting environment.Some research indicates that only in the year of2003,the worldwide production of aluminum cans was up to 3.563×10⁶T,which consisted of one-fourth of aluminum rolling products.Most of them are disposed by landfill,and the other are retailed to manufacturers,while the rest small portions are transported to aluminum recycling system.Recycling and reusing waste cans to produce high valued chemicals can not only use this waste part for secondary energy utilization,to release environmental pollution and land scarcity for this reason,but also the produced chemicals can be applied industrially.Generally speaking,waste cans are very promising,and it is suitable for making hydrogen and reducing CO₂ from hot splitting water.The method of using massive waste metal materials to hydrogenation by CO₂ need be developed further.This paper focus on hydrothermal reduction of CO₂,acting waste cans as reductants and no added catalysts.Also,discussing the product yield contribution from can's surface organic films,conducting kinetic of formate,mixed rates experiments and so on.First of all,aluminum waste cans?Pepsi Cola?as reductants,we found that the formte yield is almost not affected by surface organic films and size of grains.Reaction time,reaction temperature,filling rate of solvent,amount of materials and pH value to Investigate the impact of producing formate yield.The optimal reaction conditions are 573 K,2 h,2 mL?0.1 mol/L NaOH,1 mmol NaHCO₃ and 9 mmol Al-can strips,and the best yield is65%.After hydrothermal reaction,Al-can strips are converted into powdered AlO?OH?,which has clear rod-like structure.BET report indicates,this kind of AlO?OH?has 96.9 m2·g^-11 surface area and 68.0?pore diameter.In addition,the inner mechanism of NaHCO₃ reducing into formate is studied.The kinetic of downtrend of formate concentration and the activation energy are analyzed.Next,iron waste cans?Red Bull?as reductants,we found that the removal of surface organic films will make formate yield decrease to some extent,also,the yield will not notably increase with the optimization of reaction time,reaction temperature and amount of Fe-can strips by unpolished cans.The yields are always less than 3%.Under set conditions,the change of pH value can double the formate yield,and the corresponding optimal NaOH concertation is 0.5 mol/L.However,the organic film is the major concentration of acetate.The best yield of acetate is 1.7%in 623 K,2 h.It can be a reality of producing acetate industrially in a large scale if the reaction conditions can be optimized continuously.Last but not least,the experimental yields from different mixed rates between two cans are higher than theoretical calculation value,which can enlarge format yield.It is suggested to be industrial application.