Adsorption Of CO₂ By Bagasse Biochar Reduced Graphene Oxide Composite Adsorbent

Since the industrial revolution,global CO₂ emissions have increased year by year.CO₂ emissions have led to a series of global environmental problems,such as melting glaciers,rising sea levels,frequent extreme weather,etc,which have a serious impact on human health worldwide and the global ecosystem balance.The IPCC pointed out that by 2050,if the global average temperature is to be controlled within 2.0-2.4°C based on the global average temperature in 2000,the global need to reduce carbon emissions by at least 50%-80%.In China's energy structure,disposable energy,including oil and coal,accounts for 79.2%of total energy,which is an important source of CO₂ emissions.Although China's energy structure is diversifying,it is difficult to change dramatically in the short term,therefore,CO₂ capture as an effective means to control carbon emissions has become particularly necessary..At present,the post-combustion capture method in CO₂ capture technology has received extensive attention,and the CO₂ capture technology using solid adsorbents has become a research hotspot.As one of the main producing areas of sugar cane,Yunnan Province produces a large amount of waste bagasse which can be used as biomass to prepare biochar for CO₂ capture and reuse of waste.In this paper,bagasse biochar?BC?was prepared by using bagasse as raw material,and it was modified by graphene oxide compound modification and metal oxide modification to obtain composite adsorbent?BG?and metal oxide supported composite adsorbent?BG-Fe₃O₄,BG-CuO?and the physicochemical characterization of BET,SEM,XRD,FT-IR and XPS were carried out to explore the CO₂ adsorption mechanism by adsorbents.?1?Under the conditions of normal temperature and pressure?30°C,1 atm?,the effects of conditions such as pyrolysis temperature,composite ratio and metal oxide loading on CO₂ capture were studied.The results showed that the bagasse biochar prepared at a pyrolysis temperature of 900°C,N₂ atmosphere,exhibited a higher CO₂capture capacity(58mg·g^-1);When the composite ratio of bagasse biochar reduced graphene oxide is 91wt%:9wt%,the composite adsorbent exhibits the highest CO₂adsorption capacity(77mg·g^-1);The optimal loading capacity of Fe₃O₄ and CuO is30wt%and 5wt%,and the adsorption capacity of BG-Fe₃O₄ and BG-CuO is 92mg·g^-1 and 81mg·g^-1 respectively?2?The effects of adsorption temperature and gas flow rate on CO₂ capture by BG adsorbent and the adsorption temperatures of BG-Fe₃O₄ and BG-CuO were studied.It was found that BG,BG-Fe₃O₄ and BG-CuO exhibited the best CO₂ adsorption capacity at gas flow rates of 30?,1 atm and 50 ml/min of CO₂.?3?The characterization of the adsorbent showed that the biochar obtained at pyrolysis temperature of 900°C has high specific surface area,pore volume and high aromatization structure,which is helpful for CO₂ adsorption;the-OH,-COOH,and-C-O groups in reduced graphene oxide can enhance the surface polarity of the adsorbent and the adsorption capacity of the adsorbent for CO₂;Fe₃O₄ and CuO can convert CO₂ into CO₃^2-and fix it on the surface of adsorbent,thus enhancing the adsorption capacity of CO₂.