Presentation on theme: "Surface characteristics of porous coconut shell carbon impregnated with bimetallic catalysts IBRAHIM Yakub, KHAIRUL Anwar Mohd Said, NORSUZAILINA Mohamed."— Presentation transcript:
Surface characteristics of porous coconut shell carbon impregnated with bimetallic catalysts IBRAHIM Yakub, KHAIRUL Anwar Mohd Said, NORSUZAILINA Mohamed Sutan, YUN Hin Taufiq-Yap and SURAHIM Mohamad
Introduction Nitrogen Oxides (NOx) from stationary sources such as incinerators and power plants are toxic environmental pollutants Selective catalytic reduction (SCR) is currently the most widely used method to reduce NOx emissions in power plants and automobile application Much attention has been paid to the development of low-temperature SCR catalysts, capable of undergoing a reaction under 300 o C because; Suitable for relatively cheap and readily available precursors such as activated carbon the exhaust contains less particulate matter that may cause catalyst deactivation and poisoning, as well as other pollutants such as SO 2 and Arsenic carbon fiber and activated coke showed high NOx removal efficiency at low temperatures (100 – 250 o C)
Objective To determine the potential of an SCR catalyst derived from coconut shell carbon in low-temperature SCR system using; surface chemistry characterization morphology observation
Methodology Sample Preparation CSC was washed and oven dried, drenched in an equimolar mixture of copper nitrate and manganese acetate and continuously stirred for 24 hrs at room temperature The impregnated CSC was heat-treated under clean ambient air at 250 oC for 8 hrs and cooled to room temperature in a vacuumed desiccator Surface chemistry characterization Using H2 temperature-programmed reduction (H2-TPR), CO 2 temperature-programmed desorption (CO2-TPD), NH3 temperature- programmed desorption (NH 3 -TPD) Morphology observation Using N2 adsorption-and- desorption and scanning electron microscope (SEM)
Results & Discussion Surface Area The BET surface area of the catalyst is larger than the carbon mainly due to the increase in external surface area after synthesis process. This improvement is beneficial as more available sites can be introduced for the SCR reaction to take place. PropertiesCSCCu-Mn/CSC BET surface area (m 2 /g) 819.2903.3 External surface area (m 2 /g) 35.64187.8 Internal surface area (m 2 /g) 783.5715.5 Micro pore volume (cc/g) 39.2135.05 Average pore diameter (Ǻ) 21.2826.12
N 2 adsorption-desorption isotherm BET adsorption isotherms for both samples are similar, that is Type IV hysteresis loop for CSC is Type H3 while for Cu-Mn/CSC is Type H4 the calcination process had resulted in a more uniform distribution of slit-shape pores formed by aggregates of plate-like particles
Surface acidity From the 4,599 μmol NH 3 desorbed, almost 50% was allowed to detach from the basic functional groups at 674 o C while the other half at 871 o C This implies that ammonia was strongly adsorbed by the catalyst, either at the surface or at the metal oxides where it will react with NOx to form nitrogen
Surface basicity There were 6,341 μmol CO 2 desorbed form each gram of the catalyst Most of the CO 2 evolved at high temperature between 600 to 900 o C which suggests the presence of lactones
Catalyst reducibility Copper and manganese oxides were reduced at temperature around 246 and 574 o C with at least 80% of the reduction occurred at the higher temperature
Conclusion Coconut shell carbon utilized as SCR catalyst support showed suitable surface characteristics to be applied in low-temperature SCR system N 2 adsorption-and-desorption test showed increase in surface area and change in hysteresis loop from Type H3 to Type H4 H 2 -TPR showed the presence of the bimetallic catalysts which were both reduced CO 2 -TPD and NH 3 -TPD indicated higher presence of acidic functional groups on the catalyst that is suitable for ammonia (reductant in SCR) adsorption
Acknowledgement The authors acknowledge the Ministry of Education Malaysia for the fund RAGS/c(7)/940/2012(41) as well as Universiti Malaysia Sarawak and Universiti Putra Malaysia for the research facilities.
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