CO2 adsorption with solid sorbents is a possible and promising option for post-combustion CO2 capture strategies. With the aim to reach a cost- effective overall process, sorbents are required to be low-cost and versatile in typical post-combustion conditions (CO2 1-15% vol. and atmospheric pressure). In this framework, sorbents derived from re-cycle and/or re-use of wastes used as starting valued material as alternatives for their disposal are particularly welcome. The development of technologies devoted to cost reduction by using lignocellulosic biomasses generated from the industrial processing of agricultural raw materials is a hot research topic. Agroindustry annually generates enormous amounts of residues and their reduction by utilization might mitigate environmental pollution and increase energy savings. Rice husk (RH) is one of the most widely available agricultural waste in rice-producing countries all around the world. RH contains around 75-90 wt.% of organic matter as cellulose, lignin etc. Mineral components are mostly composed of silica (87-97 wt.% of total ashes). A fruitful utilization of RH is helpful to mitigate the disposal problem and to reduce the cost of waste treatment. A possible new life for RH is its re-use for manufacturing new materials as sorbents for CO2 capture. In a view of exploiting the advantages and shortcomings of using a real biomass as starting material for the preparation of sorbent for CO2 capture applications, we prepared different hybrid materials starting from our experience in the production of hybrid carbon- ferric oxide materials containing as carbonaceous support a model and non-porous material (carbon black) [Alfè, PROCI, 2015]. To this aim carbonized RH (cRH) was coated with different amount of ferric oxide particles (FM) as raw FM and as nano disperse FM particles (nFM). A first set of cRH/FM hybrids was produced by varying the amount of cRH from 20 to 80 wt.% following the same approach presented in [Alfè, PROCI, 2015; Gargiulo, App Surf Sci, 2016]. A second set of cRH/nFM hybrids was produced by varying the amount of cRH from 20 to 80 wt.% and by conducting the co-precipitation of nFM in strong alkalinic conditions and in presence of an appropriate surfactant to prevent nFM agglomeration [Utkan, J Colloid Interface Sci, 2011]. The CO2 sorption performances have been evaluated in a lab-scale fixed bed reactor. The materials of the two sets were structural characterized and a careful attention to the modification of cRH in the applied reaction conditions was payed (moderate alkaline medium in the case of FM co-precipitation and strong alkaline medium in the case of nFM coprecipitation). Preliminary data have been acquired and reviewed to understand the effects of composite preparation and morphology on the CO2 sorption capacity.
FROM AGRICULTURAL WASTES TO ADVANCED SORBENT MATERIALS FOR CO2 CAPTURE: ADVANTAGES AND SHORTCOMINGS OF CARBONIZED RICE HUSK
V Gargiulo;P Ammendola;F Raganati;R Chirone;M Alfe
2017
Abstract
CO2 adsorption with solid sorbents is a possible and promising option for post-combustion CO2 capture strategies. With the aim to reach a cost- effective overall process, sorbents are required to be low-cost and versatile in typical post-combustion conditions (CO2 1-15% vol. and atmospheric pressure). In this framework, sorbents derived from re-cycle and/or re-use of wastes used as starting valued material as alternatives for their disposal are particularly welcome. The development of technologies devoted to cost reduction by using lignocellulosic biomasses generated from the industrial processing of agricultural raw materials is a hot research topic. Agroindustry annually generates enormous amounts of residues and their reduction by utilization might mitigate environmental pollution and increase energy savings. Rice husk (RH) is one of the most widely available agricultural waste in rice-producing countries all around the world. RH contains around 75-90 wt.% of organic matter as cellulose, lignin etc. Mineral components are mostly composed of silica (87-97 wt.% of total ashes). A fruitful utilization of RH is helpful to mitigate the disposal problem and to reduce the cost of waste treatment. A possible new life for RH is its re-use for manufacturing new materials as sorbents for CO2 capture. In a view of exploiting the advantages and shortcomings of using a real biomass as starting material for the preparation of sorbent for CO2 capture applications, we prepared different hybrid materials starting from our experience in the production of hybrid carbon- ferric oxide materials containing as carbonaceous support a model and non-porous material (carbon black) [Alfè, PROCI, 2015]. To this aim carbonized RH (cRH) was coated with different amount of ferric oxide particles (FM) as raw FM and as nano disperse FM particles (nFM). A first set of cRH/FM hybrids was produced by varying the amount of cRH from 20 to 80 wt.% following the same approach presented in [Alfè, PROCI, 2015; Gargiulo, App Surf Sci, 2016]. A second set of cRH/nFM hybrids was produced by varying the amount of cRH from 20 to 80 wt.% and by conducting the co-precipitation of nFM in strong alkalinic conditions and in presence of an appropriate surfactant to prevent nFM agglomeration [Utkan, J Colloid Interface Sci, 2011]. The CO2 sorption performances have been evaluated in a lab-scale fixed bed reactor. The materials of the two sets were structural characterized and a careful attention to the modification of cRH in the applied reaction conditions was payed (moderate alkaline medium in the case of FM co-precipitation and strong alkaline medium in the case of nFM coprecipitation). Preliminary data have been acquired and reviewed to understand the effects of composite preparation and morphology on the CO2 sorption capacity.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
