Studies On Synthesis Of Polyhydroxybutyrate From Carbon Dioxide Storage Materials By Alcohol And Amine

With the acceleration progress of global industrialization and urbanization,CO₂emissions gradually increasing,and CO₂was be considered to be one of the main causes of greenhouse gases.How to reduce CO₂emissions and transform CO₂into high value-added products has great significance to the prevention and control of greenhouse effect.At present,the carbon capture and storage(CCS)or the carbon capture and utilization(CCU)were commonly used to treat CO₂.Among them,amine was the most widely used method to capture CO₂,but the high volatility of amine was easy to cause secondary air pollution.For this reason,1,2-propanediamine(1,2-DAP)was fixed with triethylene glycol(TEG).The density,viscosity and surface tension of TEG+1,2-DAP binary solution were further determined and analyzed,Combined with Ultraviolet-visible spectrophotometer(UV-Vis),Fourier Transform infrared spectroscopy(FTIR)and Fluorescence spectrophotometer(Fluorescence),it was found that when the molar ratio of TEG to 1,2-DAP was 1:1,the interaction between TEG and 1,2-DAP was the strongest,and TEG has the best effect in fixing amine.The binary solution of TEG and 1,2-DAP with the molar ratio of 1:1 was used to capture CO₂,and the ventilation rate of CO₂was 300 m L/min,the absorption rate was the highest(0.6865 mol CO₂/1 mol 1,2-DAP).The white solid powder generated after CO₂capture was named the carbon dioxide storage material(CO₂SM).CO₂SM was characterized by X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),Fourier Transform infrared spectroscopy(FTIR)and Nuclear magnetic resonance(¹³CNMR).The results show that CO₂SM was a kind of materials similar to alkyl carbonate structure,which not only provide nutrients for plant growth,but also provide effective carbon and nitrogen sources for microalgae cultivation.Different concentrations and kinds of CO₂SM were added into zarrouk medium to culture spirulina platensis for synthesize polyhydroxyalkanoates(PHB).It was found that the synthesis of PHB reached the maximum(9.4 mg/g)when 0.5 g/L CO₂SM TEG+1,2-DAP was added under aeration condition.It was higher than the synthesis amount of PHB(5.6 mg/g)under nitrogen deficiency in literature.Although the carbamate in CO₂SM could inhibit the growth and cytochrome synthesis of spirulina.During the cultivation of spirulina,CO₂SM provided effective carbon and nitrogen sources for the growth of spirulina,increased the C retention,augment the mass transfer of CO₂to photoautotrophs,and promoted the accumulation of PHB in Spirulina.Therefore,the method not only effectively improve the carbon sequestration efficiency of microalgae,but also effectively transform the CO₂capture material into resources and generate high value-added downstream products.