K2CO3 Content Research Articles

Optimization of High-Temperature CO2 Capture by Lithium Orthosilicate-Based Sorbents Using Response Surface Methodology

The major challenge in the current context of the rising world energy demand is to limit the global temperature increase for mitigating climate change. This goal requires a large reduction of CO2 emissions, mainly produced by power generation and industrial processes using fossil fuels. In this study, a novel methodology for K2CO3-doped Li4SiO4 sorbents production for CO2 capture at high temperatures was adopted based on the Design of Experiments (DoE). This innovative approach systematically tested different synthesis (temperature and K2CO3 content) and adsorption conditions (sorption temperature and CO2 concentration), allowing for the assessment of individual and interactive effects of process parameters. The Response Surface Methodology (RSM) was employed to obtain non-linear predictive models of CO2 uptake and Li4SiO4 conversion. The results of RSM analysis evidenced a maximum adsorption capacity of 196.4 mg/g for a sorbent produced at 600 °C and with 36.9 wt% of K2CO3, tested at 500 °C and 4 vol% of CO2. Whereas at 50 vol% of CO2, the best uptake of 295.6 mg/g was obtained with a sorbent synthesized at 600 °C, containing less K2CO3 (17.1 wt%) and tested at a higher temperature (662 °C). These findings demonstrate that K2CO3-doped Li4SiO4 sorbents can be tailored to maximize CO2 capture under various operating conditions, making them suitable for use in industrial processes.

Extraction of K2CO3 from empty palm fruit bunch ash and properties analysis

Empty oil palm fruit bunches (EPFB) are the largest solid waste generated from palm oil mills. Accounting for 21-23 % of the total fresh fruit bunches. EFB ash contains K (Potassium) which can be recovered as K2CO3 through extraction. This research aims to recover K2CO3 from empty oil palm fruit bunches (EPFB) as a catalyst raw material because it is alkaline using the K2CO3 extraction method from the ash of empty oil palm fruit bunches (EPFB), which begins with a combustion process at a temperature of 700 oC to obtain ash. Ash extraction was carried out in 2 stages using water as a solvent. The K2CO3 yield from empty palm fruit bunch ash reached 57.28 %. The alkalinity test showed that the K2CO3 content in the solid extract reached 85.91 %. The properties of the ash and K2CO3 produced were analyzed using XRF, XRD and FTIR. The results of XRF analysis show that the potassium content in the ash contains the element K (potassium) which is quite large, namely 71.24 % and after extraction the purity of potassium oxide reaches 97.08 %. XRD analysis of the results of the synthesis of potassium carbonate from empty oil palm fruit bunches showed that the intensity of the material beam was obtained in a 2ϴ pattern which was lower than the intensity pattern of pure potassium carbonate. The results of FTIR analysis show that the spectrum of carbonate ions from the EPFB C-O bend is visible at 1359,879 and 700.75 cm-1 and these results are similaire to the pure carbonate ion vibration mode.

Effects of Na2O, K2O and B2O3 on Deformability of SiO2-MnO-Al2O3 Inclusion in High-Carbon Steel

Cord steel is used for making tire frames and wire saws for cutting silicon wafers. The diameter of mainstream cutting wire has been developed to be lower than 100 μm. The size and deformation ability of inclusions are very important to the wire breaking rate of cord steel during the drawing process. In order to improve the deformation ability of the inclusions in cord steel, alkali metal oxide was added into the molten steel to improve the inclusions in the steel so as to obtain good, plastic, low-melting-point inclusions. Mass fractions of 0.3%, 0.5% and 1.0% K2CO3, Na2CO3 and B2O3 were added into cord steel, which were melted in 10 furnaces (including 0% alkali metal oxides, mass fractions of 0.3%/0.5%/1.0% K2CO3, Na2CO3 and B2O3). The morphology and composition of inclusions were observed by SEM-EDS. Factsage phase diagram calculations and experimental results show that, with the increase in Na2CO3 content in cord steel, the aluminum content in the inclusions gradually decreased. When the mass fraction of Na2CO3 was 0.5% per ton, most of the inclusions in the steel fell in the low melting point region (less than 1300 °C). With the increase in K2CO3 content in cord steel, the silicon content in the inclusions decreased gradually. When the mass fraction of K2CO3 was 0.5% per ton, most of the inclusions in the steel fell in the low melting point region. The deformation ability of the inclusions added with 0.5% Na2CO3 in the steel during forging was better than that of the inclusions added with 0.5% K2CO3. After adding B2O3, the inclusions in the steel were SiO2-MnO-Al2O3 inclusions or inclusions with SiO2-MnO-Al2O3 as the core and BN wrapped around. Boron could not be dissolved into the inclusions for plastic modification.

Arang Kulit Biji Kakao (Theobroma cacao L) sebagai Adsorben untuk Menurunkan Kadar Asam Lemak Bebas pada Pembuatan Biodiesel dari Minyak Jelantah

Indonesia as one of the largest producing and exporting countries of crude palm oil (CPO). However, Indonesia still has not utilized the potential of the waste that generated by using CPO as cooking oil, namely used cooking oil. The high content of free fatty acids (FFA) in used cooking oil will cause the saponification reaction and interfere the processing into biodiesel. Cocoa bean shell charcoal (Theobroma cacao L) has a K2CO3 content similar to its commercial product, and contains some traces of silicates and sulfates so that it can increase the efficiency of reducing free fatty acids. In this study, tests were carried out to reduce FFA levels in used cooking oil using charcoal from cocoa bean husks activated with HCl, varying the concentrations of 6, 8 and 10 Molar, as well as the temperature treatment during the process of mixing used cooking oil with activated charcoal adsorbent, which was 75 , 100, and 150°C. The best FFA reduction results were found in the A3T2 reactor which reached 80%, where the best HCl concentration was 10 Molar and the temperature of the mixing process with the adsorbent was 100°C and produced a biodiesel yield of 75%. The quality of the biodiesel produced complies with SNI 7182-2015 standards, 867 kg/m3 of density, 0.5 mg KOH/g of acid number, 1.52 cSt of kinematic viscosity, 48.081 MJ/kg of calorivic value and 143.99%- mass of methyl ester content.

Catalytic Effect of Alkali Metals on the Gasification Dissolution Reaction and Deep Reaction Behavior of Metallurgical Cokes.

In this paper, the deep reaction behaviors of tamping and top-charging cokes with different K2CO3 and Na2CO3 contents were investigated and the evolution of the functional group structure and the carbon structure of coke with the extension of the deep reaction was clarified. The results showed that the deep reaction gasification of coke steadily increased with the K2CO3 and Na2CO3 content. However, the catalytic effect of different contents of K2CO3 seemed to be stronger than that of different contents of Na2CO3. Meanwhile, the catalytic effect of alkali metals on the gasification reaction of tamping coke was more significant. The gasification dissolution of coke gradually decreased from the outside to the inside of the particle with the extension of the deep reaction, while the catalytic effect of K2CO3 and Na2CO3 seemed to be more dramatic on surface of the coke particle. In contrast, the gasification dissolution reaction on the surface of tamping coke was more severe; consequently, the surface pore area of tamping coke was much higher than that of top-charging coke. According to the variations in the functional group structure of cokes, aromatic hydrocarbon gradually became the dominant functional group in the coke structure with the extension of the deep reaction. The above variation led to a gradual decrease in the reactivity of coke, though the decomposition reactions of oxygen-containing functional groups in coke were promoted to some extent by the addition of K2CO3. With the extension of the deep reaction of coke, amorphous carbon was gradually transformed into sequential carbon.

Synthesis and characterization of form-stable carbonate/steel slag composite materials for thermal energy storage

It is of practical importance to develop form stable composite phase change materials (FSPCMs) for high temperature thermal energy storage. Carbonates are promising candidates as the phase change material and steel slag is a promising economical skeleton material. However, the molten carbonates (Na2CO3 and K2CO3) react with steel slag (SS) at high temperature. Here, a two-step process was developed to overcome this problem. Firstly, the modified steel slag (MSS) was obtained by activation of the two carbonates, and secondly, FSPCMs were synthesized by mix-sintering method. The obtained K2CO3/KMSS FSPCMs kept better shape than that of Na2CO3/NMSS FSPCMs after the thermal cycles. Further test showed that K2CO3 had good chemical compatibility with KMSS and was uniformly distributed. With the increased K2CO3 content, the latent heat of K2CO3/KMSS FSPCMs gradually increases, and the measured latent heat was consistent with the calculated values. With mass ratio 4:6 (40K2CO3/60KMSS), the developed FSPCM showed the best thermal stability, the latent heat attenuation was 7.08%, and the mass loss was 6.56% after 200 thermal cycles.

Molten salt template-assisted synthesis of N, S-codoped hierarchically porous carbon nanosheets for efficient energy storage

To enrich the type of carbons for double-layer supercapacitors and optimize their electrochemical performances, N/S co-doped hierarchical porous carbons (KISPCs) with well-balanced pore characteristic have been prepared by taking ginkgo leaf as carbon source and KCl/K2CO3 molten-salt as template/activation agent. The as-obtained carbons possess a well-developed interconnected sheet-like structure, accompanying with high N, S and O contents, conductive to abundant ions transport channels and exposure of more ions-accessible active sites. Moreover, the types and contents of surface functional groups of hierarchical porous carbon could also be adjusted by K2CO3 content. A symmetrical supercapacitor was assembled to validate its electrochemical performance. The KISPCs electrodes manifest a specific capacitance of 215.2 F g−1 at 0.05 A g−1, splendid capacitance retention of 78.9 % (169.8 F g−1 at 20 A g−1) and exceptional cycling stability with only 1.6 % capacity decay after 10000 charge/discharge cycles. This work can afford promising new tactics for the preparation of hierarchical porous carbon nanosheets and offer insights into the application of energy storage fields.

Extraction of SiO2 from gasified rice husk carbon simultaneously rice husk activated carbon production: Restudy on product properties, activation mechanism, and evolution law of pore structure

The goal of this work was to provide a theoretical basis for efficient and harmless utilization of gasified rice husk carbon (RHC), and further understand its activation mechanism and evolution law of pore structure. K2CO3 was used to extract SiO2 from RHC, and then the rice husk activated carbon (RAC) was prepared by activating the separated rice husk activated carbon precursor (ACP). Results showed that the specific surface area of the RAC prepared via the ACP was 1006.208 m2/g upon the yield of SiO2 was 20.64%. Compared with the particle size of RHC, the K2CO3 mass fraction have a significant effect on the yield of SiO2 and the K2CO3 content of ACP surface The activation process of ACP mainly depended on the content of K2CO3 adsorbed on its inner surface and internal structure. With an increase in K2CO3mass fraction, the pore structure of RAC roughly went through two primary stages (full development period to transitional development period). Besides, SiO2 has a great amount of ∼5 nm of mesopores and tended to crystallize upon sintered at 950°C for 4 h

Water removal in the alkaline electrochemical valorization of glycerol by pervaporation

Glycerol, as a by-product of biodiesel industries, can be converted into a broad range of high value-added products chemically in the presence of hetero/homogeneous catalysts and also electrochemically in electrolyzers. Using an alkaline medium for glycerol conversion increases the yield of the electrochemical reaction. In several glycerol valorization reactions, water is used as a solvent or is produced as a by-product. Excess water reduces the reaction conversion and hinders the efficiency in alkaline solutions, and hence must be maintained at a low concentration. The removal of water from aqueous salt solutions containing soluble organic species is a very challenging extraction due to the low activity of water.This research seeks to separate excess water from the highly alkaline ternary mixture composed of glycerol, water, and potassium carbonate (K2CO3) by pervaporation. The performance of three commercial hydrophilic PVA-based membranes namely PERVAP™ 4100, PERVAP™ 4101, and PERVAP™ 4155 from DeltaMem AG, Switzerland, was studied in terms of stability, permeability, selectivity, and also lifetime by considering the effect of temperature (25 °C, 45 °C, 55 °C, and 70 °C), water content, and K2CO3 content. Results show that the membranes rejected glycerol and K2CO3 completely. The presence of the K2CO3 in the solution decreased water flux, in part due to reducing water activity.

Nonlinear electrical properties and dielectric properties of ZnO ceramics doped with K2CO3

ZnO ceramics with different amounts of K2CO3 from 0.0 to 1.0 mol% are prepared by traditional solid-state sintering technique. The K2CO3-doping effects on the microstructure, nonlinear electrical properties and dielectric properties of ZnO ceramics are investigated. The grain size of ZnO ceramics increases from 0.9 to 1.5 μm with increasing K2CO3 content. The leakage current density versus electric field characteristics indicate that ZnO ceramic samples exhibit similar nonlinear electrical properties. The switching field and nonlinear coefficient decrease in the range of 246.2 to 1.3 V/mm and 5.3 to 2.4 with the increase of K2CO3 content. The varistor voltage decreases from 344.9 to 2.0 V/mm, while the leakage current increases from 323.0 to 646.1 μA. Meanwhile, as K2CO3 content increases, the dielectric constant and dielectric loss of ZnO ceramics are improved in the frequency range from 102 to 106 Hz at room temperature.

Influence of agriculture fertilizer for the enhanced growth and astaxanthin production from Haematococcus lacustris RRGK isolated from Himachal Pradesh, India

In the present study, Haematococcus lacustris RRGK which is the former name of H. lacustris HPI-001 isolated from Himachal Pradesh, India, and another strain H. lacustris SAG-19a retrieved from Gottingen Culture Collection, Germany, were used. The H. lacustris SAG-19a served as a control. The both strains were grown in a Bold basal medium in which the components of NaNO3, K2HPO4∙3H2O and KH2PO4 were replaced with agriculture fertilizers such as NPK (17:17:17), urea (CH4N2O) and DAP (diammonium phosphate; (NH4)2HPO4 + potash (K2CO3) in different concentrations. The isolate of H. lacustris HPI-001 showed maximum growth at 1.2 mM NPK, while the H. lacustris SAG-19a showed maximum growth at 1.5 mM. However, both the strains showed maximum astaxanthin content at 0.6 mM NPK. The H. lacustris HPI-001 showed a maximum growth and astaxanthin content with 3.3 mM and 4.9 mM of urea, respectively, while H. lacustris SAG-19a showed maximum growth and astaxanthin accumulation with 3.3 mM and 6.6 mM of urea, respectively. The H. lacustris HPI-001 showed maximum growth at 250 mg/L (NH4)2HPO4 + 200 mg/L K2CO3 and maximum astaxanthin content at 150 mg/L (NH4)2HPO4 + 100 mg/L K2CO3, while the maximum growth in H. lacustris SAG-19a was observed at 200 mg/L (NH4)2HPO4 + 150 mg/L K2CO3, and the maximum astaxanthin content at 150 mg/L (NH4)2HPO4 + 100 mg/L K2CO3. The basal medium was also amended with the addition of commercial NaHCO3 wherein the maximum growth and content of astaxanthin in H. lacustris HPI-001 was at 0.6 mM and 1.5 mM of NaHCO3, respectively. The H. lacustris SAG-19a showed maximum growth and astaxanthin content at 1.5 mM and 0.6 mM, respectively. Based on the investigation, a medium was formulated and named as modified HPI-001 medium. The results of the present study suggest that commercial agricultural fertilizers may be used as excellent substitutes to enhance cell growth and astaxanthin production in H. lacustris.

Thermodynamic and kinetic properties of NH3-K2CO3-CO2-H2O system for carbon capture applications

An innovative solvent based on the quaternary system CO2-NH3-K2CO3-H2O is reported and characterized in terms of its thermodynamic properties and rate of CO2 absorption. Thermodynamic properties of the solvent such as vapor-liquid equilibrium, solid-liquid equilibrium, and the heat of desorption were modelled with the Extended UNIQUAC thermodynamic model. The kinetics of CO2 absorption in the solvent were studied experimentally with a wetted wall column set-up. The absorption rate was investigated with respect to temperature, ammonia concentration, potassium carbonate concentration, and CO2 loading, under the typical operating conditions of a capture plant. Globally, the solvent has a number of interesting properties for CO2 capture applications. Indeed, adding K2CO3 to the ammonia solvent reduced both the ammonia slip and the heat of desorption. Experimental analysis showed that the kinetics of absorption were mainly influenced by the reaction between free ammonia and CO2. Hence, the overall mass transfer coefficient decreased when increasing the K2CO3 content of the solvent.

Effect of component content variation on composition and structure of activated carbon in PVDF:K2CO3.

Percolative composites consisting of potassium carbonate dispersed in polyvinylidene fluoride (PVDF) polymeric matrix have shown high dielectric constant and electrical conductivity due to the formation of chemically activated carbon interfaces in the composite. In this paper, a series of PVDF/K2CO3 films with different component contents were prepared and investigated by Raman and X-ray photoelectron spectroscopies to clarify chemical composition, structure and formation mechanism of activated carbon. The results revealed the presence of a reaction loop to consume both constituent phases and the formation of sp2 carbon rings in the yielded activated carbon due to cross-linking dehydrofluorination of PVDF during thermal treatment. The sp2 content showed a non-linear dependence on K2CO3 content with the presence of an optimal value corresponding to the highest dielectric constant and electrical conductivity. This study thus can give a direction for future fabrication of PVDF/K2CO3 electrode materials for supercapacitors.

Melting and subsolidus phase relations in the system K2CO3–MgCO3 at 3 GPa

ABSTRACTAs part of an investigation of carbonate systems under mantle pressures and temperatures, phase relations in the K2CO3–MgCO3 system have been studied at 3 GPa and 800–1300°C. Subsolidus assemblages comprise the stability fields of K2CO3 + K2Mg(CO3)2 and K2Mg(CO3)2 + MgCO3 with the transition boundary near 50 mol% K2CO3 in the system. The K2CO3–K2Mg(CO3)2 eutectic is located at 840°C and 52 mol% K2CO3. The K2CO3 content in the melt coexisting with potassium carbonate increases to 85 mol% as temperature increases to 1050°C. K2CO3 remains solid up to 1250 and melts at 1300°C. K2Mg(CO3)2 melts incongruently at 890°C to produce magnesite and a liquid containing 51 mol% K2CO3. As temperature increases to 1300°C, the K2CO3 content in the liquid coexisting with magnesite decreases to 27 mol%.

Parametric study of pyrolysis and steam gasification of rice straw in presence of K2CO3

A parametric study of pyrolysis and steam gasification of rice straw (RS) was performed to investigate the effect of the presence of K2CO3 on the behavior of gas evolution, gas component distribution, pyrolysis/gasification reactivity, the quality and volume of synthetic gas. During pyrolysis, with the increase in K2CO3 content in RS (i) the instantaneous CO2 concentration was increased while CO concentration was relatively stable; (ii) the yield of CO2 and H2 increased on the cost of CH4. During steam gasification of RS, with the increase in K2CO3 content in RS (i) the instantaneous concentration of CO2 and H2 increased while instantaneous concentration of CO and CH4 decreased; (ii) the yield of CO2 and H2 production and total yield increased; and (iii) yield of CO and CH4 production followed the order: 9% K2CO3 RS<6% K2CO3 RS<raw RS<3% K2CO3 RS<water-leached RS. Water-leached RS showed the highest pyrolysis reactivity, while stream gasification reactivity was proportional to K2CO3 content in RS. The results of this study reveal that the presence of K2CO3 during pyrolysis and steam gasification of RS effectively improves production of H2 rich gas.

Novel sour water gas shift catalyst (SWGS) for lean steam to gas ratio applications

Dry powder coal gasification is emerging as one of the most energy efficient methods for coal conversion. However, the low steam content, high temperature and high content of CO in the raw syngas make it difficult for a conventional sour water gas shift catalyst to be directly used for syngas conditioning. Conventional sour water gas shift takes place at very high steam to carbon monoxide ratio (H2O/CO), often 2 or above, but the H2O/CO ratio from a dry powder coal gasifier is often less than 0.8. To develop a sour water gas shift catalyst suitable for the lean steam raw syngas, we have prepared a series of MgAl2O4 spinel modified alumina supported CoMoOx catalysts by changing the content of K2O in the promoter, and tested them under lean steam to carbon monoxide (H2O/CO) ratio conditions for sour water gas shift process. Our results show that the addition of potassium into the catalyst increases the catalyst water gas shift activity at a lean steam to gas ratio, and that catalyst activity increases with the K2O content increase in 0–10wt.% range; the potassium additive helps to increase the dispersion of MoO3 and improves catalyst strength and surface area. The increase of K2O content leads to higher catalyst activity for the CO shift reaction with little methane yield, reducing the hot spot formation in the catalyst bed. This may be due to the high K2CO3 content in the catalyst enhancing the surface affinity to steam in the syngas, and the basicity of K2CO3 depresses methane formation over the MoS2 active site. The 10.0wt.% of K2O-containing SWGS catalyst showed the highest stability even in the absence of H2S in the feed gas for up to 90min, and little H2S is released from the catalyst (reverse sulfurization) under such conditions. The optimized K2O-containing SWGS catalyst, e.g., QDB-5-10 has been used in an industrial plant for 2years in a coal to methanol plant and showed stable and unique performance under the lean steam conditions, allowing the 1st stage SWGS reactor to be well within control. The potassium carbonate included in the catalyst is stable and little leachate occurred even after 2-years of use time on stream.

The effect of the alkali additive on the highly active Ru/C catalyst for water gas shift reaction

The present study reported the results on the water–gas shift (WGS) reaction over a series of Ru/C catalysts. It was found that the reduction method showed a remarkable effect on the catalytic activity of Ru/C catalysts over WGS reaction, which increased in an order of the reduction by NaBH4, ethylene glycol, H2. It has been shown that alkali additives with K2CO3 significantly improved the activity of the Ru/C catalysts. XPS results indicated that Ru species were further oxidized by the addition of K2CO3, which indicated an electron transfer from the alkali metal to the substrate, resulting in stronger bonding of the adsorbed gas. FTIR results showed that the absorption peak intensity of H2O and hydroxyl group increased with the increase of K2CO3 content, due to the strong hygroscopic ability of K2CO3. Through the addition of K2CO3 to the Ru/C catalyst, much more water was adsorbed around the catalytic active sites, reducing the strong adsorption of CO on the active sites. Thus the addition of K2CO3 balanced the concentration of water and CO on the active sites, which was considered to be the key step for low temperature WGS reaction over Ru supported on irreducible activated carbon.

Effect of K&lt;sub&gt;2&lt;/sub&gt;CO&lt;sub&gt;3&lt;/sub&gt; Addition on the Structure and Electrical Properties of Lead-Free (Na&lt;sub&gt;0.5&lt;/sub&gt;K&lt;sub&gt;0.5&lt;/sub&gt;)NbO&lt;sub&gt;3&lt;/sub&gt;-( Na&lt;sub&gt;0.5&lt;/sub&gt;Bi&lt;sub&gt;0.5&lt;/sub&gt;)TiO&lt;sub&gt;3&lt;/sub&gt; Ceramics

K2CO3-doped 0.98(Na0.5K0.5)NbO3-0.02(Na0.5Bi0.5)TiO3 [abbreviated as 0.98NKN-0.02NBT] lead-free piezoelectric ceramics were prepared by the conventional mixed oxide process. The effects of K2CO3 additions on the crystalline structures and electrical properties of the 0.98NKN-0.02NBT ceramics were investigated. The specimens of 0.98NKN-0.02NBT ceramics added with K2CO3 maintain an orthorhombic phase. In the case of low K2CO3 content (≤ 0.3 wt%), the grain growth became remarkable. The increase of grain size favors improving the piezoelectric properties, which is known as grain size effect. The grain size effect compensates the decrease of the electromechanical coupling factor due to the hard doping effect. For 0.98NKN-0.02NBT ceramics by doping 0.3 wt% Na2CO3, the electromechanical coupling coefficients of the thickness mode kt and the planar mode kp reach 0.51 and 0.33, respectively, after sintering at 1100 oC for 3 h. Our results show that 0.98NKN-0.02NBT with the addition of 0.3 wt% K2CO3 is a good lead-free piezoelectric ceramic.

CO2 Separation by a New Solid K−Fe Sorbent

An inexpensive K−Fe-based sorbent using K2CO3 and nanoporous FeOOH was developed, and its CO2 separation performance was investigated in a fixed-bed tube reactor under differing conditions. Because of its high surface area and porous structure, FeOOH can increase CO2 capture capability by more than 70 times compared to pure K2CO3. The sorption capacity of the K−Fe sorbent reaches its peak when its K2CO3 content is 33.33 wt %, under the tested sorption conditions. The CO2 sorption capacity of the sorbent increases with an increase of moisture in gas but decreases dramatically with the elevation of the sorption temperature. The total CO2 capture capability of the K−Fe sorbent is ∼49 mg of CO2/g of sorbent at 60 °C in a 10 vol % moisture environment. The sorbent is regenerable, and its multicycle sorption capacity remains at ∼30 mg of CO2/g of sorbent when the regeneration temperature is 125 °C. Catalysis plays an important role in improving CO2 desorption, thus reducing the energy required for the CO2 separ...

Carbonization of bamboo and consecutive low temperature air activation

Raw moso bamboo (Phyllostachys pubescens) was examined to optimize the carbonization and the consecutive air activation procedure. Influence of sample size, nitrogen flow rate, heating rate and final temperature on the carbon yield and the pore structure was investigated for the raw bamboo. The short length cutting along bamboo trunk and the increase in heating rate to 40°C/min and nitrogen flow rate up to 500 ml/min was found to be advantageous for the carbonization of raw bamboo at 500°C, resulting in a surface area of 230 m2/g with a bamboo char yield of 25% on dry base. In the next step, effects of air treatment temperature, ash content and its composition on the pore development were studied for the prepared bamboo char in comparison with coconut shell char. Additional increase in surface area by 200 m2/g with 97% yield could be achieved conducting the 2-hour air treatment at 280°C for the bamboo char, whereas only a 100 m2/g rise in surface area was attained for the coconut shell char, partly due to the difference in K2CO3 content in the char.