Comparing the Performance of KOH with NaOH-Activated Anthracites in Terms of Methane Storage

Abstract

Anthracite activated carbons are proper adsorbents for methane storage. In this study, Iranian local anthracite was activated using two commonly used chemicals (sodium hydroxide and potassium hydroxide) at similar conditions and their products are compared with regard to various properties in order to find the optimal operating parameters such as temperature, chemical ratio and pyrolysis time for producing ACs with high surface area. Three activation temperatures (670, 730 and 790 °C), three chemical-to-coal ratios (2, 2.5 and 3) and two pyrolysis times (1 and 2 hours) were studied in each carbon series (NaOH and KOH). Accordingly, the pore structures of Activated carbon (ACs) were investigated accurately based on adsorption isotherms of nitrogen as well as density functional theory. In addition, their methane storage capacities were also measured and discussed. Specific volumes (microporosity and mesoporosity) of products were also calculated. The KOH ACs had higher micropore volumes, whereas NaOH ACs had relatively higher densities. The highest methane storage was obtained by a KOH AC sample with 3:1 chemical-to-coal ratio (R), activated at 730 °C for 1 hour (AK37301). The stored and delivered methane for this sample were 176 and 158 vol/vol, respectively.

Activated Carbon Produced by Pyrolysis of Waste Wood and Straw for Potential Wastewater Adsorption

“…The gas flow was set for 2500 and 4000 cm 3 /min for 60 min for 25 g of sample, which approximates a molar ratio of 1:1 and 1:2 [37]. Ahmadpour et al [27], in turn, performed the activation of macadamia nut shells using KOH and ZnCl 2 with three different preparation methods at various temperatures (600, 700 and 800 • C). The results for the surface area of the products obtained after activation using KOH at 600, 700 and 800 • C were 628, 1075 and 1169 m 2 /g, respectively.…”

“…Above 700 • C metallic potassium is formed due to reduction by carbon or hydrogen. The comparison of two typical alkaline activation agents, KOH and NaOH, revealed that in the similar condition of activating the process the biomass samples prepared with NaOH had lower surface area and micropore volumes than those with KOH [27]. However, the chemical activation process must be followed by an additional treatment to eliminate chemicals used [28].…”

Application of Artificial Neural Networks and Adaptive Neuro-Fuzzy Inference Systems to Predict Activated Carbon Properties for Methane Storage

“…Among them, chemical activation is a proper method to synthesize ACs with high surface areas for gas storage purposes (Bansal et al 1988;Simitzis and Sfyrakis 1994;Ahmadpour and Do 1997;Lozano-Castelló et al 2002). Recently, Ahmadpour et al (2013) investigated methane storage in different ACs prepared with KOH and NaOH, and they achieved a high amount of storage equal to 176 vol/vol in comparison with previous studies. Celzard et al (2007) proposed an advanced preparative strategy for the adsorptive storage of hydrogen.…”

Argila bentonítica funcionalizada com potássio: caracterização e uso como catalisar para reação de transesterificação do óleo de algodão

“…A interação M-CO (M: Al, Fe e Mg) é indicada pela banda em 663 cm -1 [26]. A banda de absorção em 995 cm -1 é atribuída a ligação K-OH [28]. No catalisador KH400 esta banda é bem definida indicando que pouco reagente foi consumido, entretanto, no KH700 estas bandas são difusas sugerindo que todo o reagente foi consumido para formação de KAlSiO 4 [29].…”