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Optimization Of Pyrolysis Conditions And Adsorption Properties Of Bone Char For Fluoride Removal From Water
15 October 2013,
09:18:44
Publication date: Available online 9 October
2013
Source:Journal of Analytical and Applied Pyrolysis
Author(s): C.K. Rojas-Mayorga , A. Bonilla-Petriciolet , I.A. Aguayo-Villareal , V. Hernández-Montoya , M.R. Moreno-Virgen , R. Tovar-Gómez , M.A. Montes-Morán
This study reports the optimization of a pyrolysis process for the synthesis of bone char for fluoride removal from water. Specifically, we have performed a detailed analysis of the adsorption properties of bone char samples obtained at different operating conditions of pyrolysis. Results show that the pyrolysis temperature plays a major role to synthetize an effective bone char for water defluoridation. In particular, the best adsorption properties of bone char for fluoride removal are obtained with those samples synthetized at 700°C. Pyrolysis temperatures higher than 700°C cause the dehydroxylation of the hydroxyapatite of bone char reducing its fluoride adsorption capacity. The maximum fluoride adsorption capacity of the bone char obtained in this study (i.e., 7.2mg/g) is higher than those reported for commercial bone chars. Finally, adsorption experiments were performed using the optimized bone char for determining kinetic, equilibrium and thermodynamic parameters of the fluoride removal from water using this adsorbent. In summary, this study shows that the optimization of pyrolysis conditions for the synthesis of bone char is useful to obtain an effective adsorbent for fluoride removal from water.
Source:Journal of Analytical and Applied Pyrolysis
Author(s): C.K. Rojas-Mayorga , A. Bonilla-Petriciolet , I.A. Aguayo-Villareal , V. Hernández-Montoya , M.R. Moreno-Virgen , R. Tovar-Gómez , M.A. Montes-Morán
This study reports the optimization of a pyrolysis process for the synthesis of bone char for fluoride removal from water. Specifically, we have performed a detailed analysis of the adsorption properties of bone char samples obtained at different operating conditions of pyrolysis. Results show that the pyrolysis temperature plays a major role to synthetize an effective bone char for water defluoridation. In particular, the best adsorption properties of bone char for fluoride removal are obtained with those samples synthetized at 700°C. Pyrolysis temperatures higher than 700°C cause the dehydroxylation of the hydroxyapatite of bone char reducing its fluoride adsorption capacity. The maximum fluoride adsorption capacity of the bone char obtained in this study (i.e., 7.2mg/g) is higher than those reported for commercial bone chars. Finally, adsorption experiments were performed using the optimized bone char for determining kinetic, equilibrium and thermodynamic parameters of the fluoride removal from water using this adsorbent. In summary, this study shows that the optimization of pyrolysis conditions for the synthesis of bone char is useful to obtain an effective adsorbent for fluoride removal from water.
Quantitative and kinetic TG-FTIR investigation on three kinds of biomass pyrolysis
15 October 2013,
09:18:44
Publication date: Available online 9 October
2013
Source:Journal of Analytical and Applied Pyrolysis
Author(s): Aihong Meng , Hui Zhou , Lin Qin , Yanguo Zhang , Qinghai Li
Biomass is applied in power generation or heat production as renewable energy resources. This paper focused on the pyrolysis in thermogravimetric (TG) analyzer of three biomasses, corn cob, tree root and bagasse, which showed different characteristics on their differential thermogravimetric (DTG) curves. In pyrolysis of corn cob, tree root and bagasse, there were three, one and two obvious peaks of DTG curves, respectively. Thermogravimetric Fourier Transform Infrared (TG-FTIR) analysis showed that the maximum mass loss rate at DTG curves was mainly due to cellulose and lignin pyrolysis, and the second mass loss rate peak of corn cob and the first one of bagasse were mainly due to pyrolysis of hemicellulose; while the first mass loss rate peak of corn cob was most likely due to breaking off of OH stretching function groups and H2O generation of sucrose pyrolysis. The main typical gaseous products were CO2, CO, H2O, CH4, NH3 and acid & aldehydes (CH3COOH or furadelhyde). Quantitative FTIR analysis showed that CO produced variation and CO2 produced before 400°C fitted with DTG curves well. IR results also indicated that hemicellulose pyrolysis had higher CH3COOH generation. Distributed activated energy model (DAEM) was applied to analyze kinetics of biomass pyrolysis. Similar to their DTG curves, the activation energy (AE) of corn cob showed four high distributions, in which the distributions of about 174.7kJ/mol and 181.6kJ/mol were highest (more than 20%), followed by that of 161.1kJ/mol (18.91%) and 140.5kJ/mol (9.08%); the AE of tree root had a distinctive distribution, which was as high as 33.9% at 181.6kJ/mol; while that of bagasse had only two distributions more than 6.8%, one is 50.69% at 181.6kJ/mol, and the other is 25.43% at 167.9kJ/mol. The pseudo-reactions fitting curves showed that the pyrolysis of corn cob was more complicated than the other two, because of more obvious pseudo-reactions contributed to the DTG curve and there were more than three main components in corn cob. It indicated that pseudo-reaction at 181.6kJ/mol was mainly contributed to cellulose pyrolysis in DTG curves, and those at 161.1kJ/mol and 167.9kJ/mol were mainly contributed to hemicellulose pyrolysis, while pseudo-reaction at 174.7kJ/mol might relate to the pyrolysis of sucrose.
Source:Journal of Analytical and Applied Pyrolysis
Author(s): Aihong Meng , Hui Zhou , Lin Qin , Yanguo Zhang , Qinghai Li
Biomass is applied in power generation or heat production as renewable energy resources. This paper focused on the pyrolysis in thermogravimetric (TG) analyzer of three biomasses, corn cob, tree root and bagasse, which showed different characteristics on their differential thermogravimetric (DTG) curves. In pyrolysis of corn cob, tree root and bagasse, there were three, one and two obvious peaks of DTG curves, respectively. Thermogravimetric Fourier Transform Infrared (TG-FTIR) analysis showed that the maximum mass loss rate at DTG curves was mainly due to cellulose and lignin pyrolysis, and the second mass loss rate peak of corn cob and the first one of bagasse were mainly due to pyrolysis of hemicellulose; while the first mass loss rate peak of corn cob was most likely due to breaking off of OH stretching function groups and H2O generation of sucrose pyrolysis. The main typical gaseous products were CO2, CO, H2O, CH4, NH3 and acid & aldehydes (CH3COOH or furadelhyde). Quantitative FTIR analysis showed that CO produced variation and CO2 produced before 400°C fitted with DTG curves well. IR results also indicated that hemicellulose pyrolysis had higher CH3COOH generation. Distributed activated energy model (DAEM) was applied to analyze kinetics of biomass pyrolysis. Similar to their DTG curves, the activation energy (AE) of corn cob showed four high distributions, in which the distributions of about 174.7kJ/mol and 181.6kJ/mol were highest (more than 20%), followed by that of 161.1kJ/mol (18.91%) and 140.5kJ/mol (9.08%); the AE of tree root had a distinctive distribution, which was as high as 33.9% at 181.6kJ/mol; while that of bagasse had only two distributions more than 6.8%, one is 50.69% at 181.6kJ/mol, and the other is 25.43% at 167.9kJ/mol. The pseudo-reactions fitting curves showed that the pyrolysis of corn cob was more complicated than the other two, because of more obvious pseudo-reactions contributed to the DTG curve and there were more than three main components in corn cob. It indicated that pseudo-reaction at 181.6kJ/mol was mainly contributed to cellulose pyrolysis in DTG curves, and those at 161.1kJ/mol and 167.9kJ/mol were mainly contributed to hemicellulose pyrolysis, while pseudo-reaction at 174.7kJ/mol might relate to the pyrolysis of sucrose.
Analytical TMAH pyrolysis of dipeptides: formation of new complex cyclic compounds related to the presence of the peptide bond
15 October 2013,
09:18:44
Publication date: Available online 9 October
2013
Source:Journal of Analytical and Applied Pyrolysis
Author(s): J. Templier , N. Gallois , S. Derenne
To evaluate the influence of the peptide bond on the nature of pyrolysis products released from proteinaceous material, 16 dipeptides were subjected to pyrolysis in the presence of TMAH. The pyrolysis products were identified by GC-MS and compared to those obtained from corresponding single amino acids. Most of the main dipeptide pyrolysis products do not correspond to the major products released upon pyrolysis of the constitutive amino acids. Depending on the considered dipeptide, different mechanisms were shown to be responsible for the formation of the major pyrolysis products. An important pathway, due to TMAH, is the direct methylation of the peptide, along with the formation of piperazine-2,5-diones (DKPs) previously observed from single amino acids. Besides these simple compounds, the formation of new cyclic compounds, more complex cyclisation derivatives based on three amino acids and cyclic products related to imidazolidinones, was revealed. Based on their structure, different possible mechanisms of formation are proposed for these cyclic compounds. It must be noted that no general trend, related to structure or polarity of the amino acids constituent of the dipeptides, allows predicting the nature of their pyrolysis products. However it can be noticed that the formation of imidazolidinone is only observed when the dipeptide contains an OH group in an aliphatic side chain. Comparison between symmetric or almost symmetric dipeptides as Met-Leu/Leu-Met or Val-Thr/Thr-Leu shows that complex DKPs are only formed from one of the dipeptide, highlighting the importance of the C- or N-terminal position of the amino acids. In most cases, the side chain from at least one constitutive amino acid is identifiable in these cyclic compounds thus evidencing the contribution of this amino acid. These products can thus be used as markers in addition to the well-known simple DKPs.
Source:Journal of Analytical and Applied Pyrolysis
Author(s): J. Templier , N. Gallois , S. Derenne
To evaluate the influence of the peptide bond on the nature of pyrolysis products released from proteinaceous material, 16 dipeptides were subjected to pyrolysis in the presence of TMAH. The pyrolysis products were identified by GC-MS and compared to those obtained from corresponding single amino acids. Most of the main dipeptide pyrolysis products do not correspond to the major products released upon pyrolysis of the constitutive amino acids. Depending on the considered dipeptide, different mechanisms were shown to be responsible for the formation of the major pyrolysis products. An important pathway, due to TMAH, is the direct methylation of the peptide, along with the formation of piperazine-2,5-diones (DKPs) previously observed from single amino acids. Besides these simple compounds, the formation of new cyclic compounds, more complex cyclisation derivatives based on three amino acids and cyclic products related to imidazolidinones, was revealed. Based on their structure, different possible mechanisms of formation are proposed for these cyclic compounds. It must be noted that no general trend, related to structure or polarity of the amino acids constituent of the dipeptides, allows predicting the nature of their pyrolysis products. However it can be noticed that the formation of imidazolidinone is only observed when the dipeptide contains an OH group in an aliphatic side chain. Comparison between symmetric or almost symmetric dipeptides as Met-Leu/Leu-Met or Val-Thr/Thr-Leu shows that complex DKPs are only formed from one of the dipeptide, highlighting the importance of the C- or N-terminal position of the amino acids. In most cases, the side chain from at least one constitutive amino acid is identifiable in these cyclic compounds thus evidencing the contribution of this amino acid. These products can thus be used as markers in addition to the well-known simple DKPs.
Levoglucosan Formation Mechanisms during Cellulose Pyrolysis
15 October 2013,
09:18:44
Publication date: Available online 8 October
2013
Source:Journal of Analytical and Applied Pyrolysis
Author(s): Xiaolei Zhang , Weihong Yang , Changqing Dong
Levoglucosan is one important primary product during cellulose pyrolysis either as an intermediate or as a product. Three available mechanisms for levoglucosan formation have been studied theoretically in this paper, which are free-radical mechanism; glucose intermediate mechanism; and levoglucosan chain-end mechanism. All the elementary reactions included in the pathway of every mechanism were investigated; thermal properties including activation energy, Gibbs free energy, and enthalpy for every pathway were also calculated. It was concluded that free-radical mechanism has the highest energy barrier during the three levoglucosan formation mechanisms, glucose intermediate mechanism has lower energy barrier than free-radical mechanism, and levoglucosan chain-end mechanism is the most reasonable pathway because of the lowest energy barrier. By comparing with the activation energy obtained from the experimental results, it was also concluded that levoglucosan chain-end mechanism fits better with the experimental data for the formation of levoglucosan
Source:Journal of Analytical and Applied Pyrolysis
Author(s): Xiaolei Zhang , Weihong Yang , Changqing Dong
Levoglucosan is one important primary product during cellulose pyrolysis either as an intermediate or as a product. Three available mechanisms for levoglucosan formation have been studied theoretically in this paper, which are free-radical mechanism; glucose intermediate mechanism; and levoglucosan chain-end mechanism. All the elementary reactions included in the pathway of every mechanism were investigated; thermal properties including activation energy, Gibbs free energy, and enthalpy for every pathway were also calculated. It was concluded that free-radical mechanism has the highest energy barrier during the three levoglucosan formation mechanisms, glucose intermediate mechanism has lower energy barrier than free-radical mechanism, and levoglucosan chain-end mechanism is the most reasonable pathway because of the lowest energy barrier. By comparing with the activation energy obtained from the experimental results, it was also concluded that levoglucosan chain-end mechanism fits better with the experimental data for the formation of levoglucosan
Thermolysis, specific heat capacity and adiabatic time-to-explosion of 2,3-dihydro-4-nitro-3-(dinitromethylene)-1H-pyrazol-5-amine potassium salt
15 October 2013,
09:18:44
Publication date: Available online 29
September 2013
Source:Journal of Analytical and Applied Pyrolysis
Author(s): Wantao Zhang , Jie Huang , Kangzhen Xu , Ting An , Shihe Yang , Jirong Song , Fengqi Zhao
2,3-Dihydro-4-nitro-3-(dinitromethylene)-1H-pyrazol-5-amine potassium salt [K(NNMPA)] was first synthesized through an unexpected reaction. Thermal decomposition of K(NNMPA) was studied with TG-FTIR-MS method. The gas products were analyzed. The specific heat capacity of K(NNMPA) was determined with a micro-DSC method and molar heat capacity is 298.9Jmol−1 K−1 at 298.15K. Adiabatic time-to-explosion of K(NNMPA) was calculated to be about 40 s. K(NNMPA) exhibits lower thermal stability than K(AHDNE), but is relatively less sensitive.
Source:Journal of Analytical and Applied Pyrolysis
Author(s): Wantao Zhang , Jie Huang , Kangzhen Xu , Ting An , Shihe Yang , Jirong Song , Fengqi Zhao
2,3-Dihydro-4-nitro-3-(dinitromethylene)-1H-pyrazol-5-amine potassium salt [K(NNMPA)] was first synthesized through an unexpected reaction. Thermal decomposition of K(NNMPA) was studied with TG-FTIR-MS method. The gas products were analyzed. The specific heat capacity of K(NNMPA) was determined with a micro-DSC method and molar heat capacity is 298.9Jmol−1 K−1 at 298.15K. Adiabatic time-to-explosion of K(NNMPA) was calculated to be about 40 s. K(NNMPA) exhibits lower thermal stability than K(AHDNE), but is relatively less sensitive.
Pyrolysis process and antioxidant activity of pyroligneous acid from Rosmarinus officinalis leaves
15 October 2013,
09:18:44
Publication date: Available online 26
September 2013
Source:Journal of Analytical and Applied Pyrolysis
Author(s): Chunhui Ma , Keguan Song , Jinghua Yu , Lei Yang , Chunjian Zhao , Wenjie Wang , Ge Zu , Yuangang Zu
We studied the pyrolysis process and products of Rosmarinus officinalis leaves. Three kinds of plant materials were used: fresh leaves, air-dried leaves, and air-dried leaves after essential oil distillation. The pyroligneous acids (PA) obtained by pyrolyzing the plant materials with different heating powers were extracted with organic solvents, including methanol, ethyl formate, dichloromethane, thiophene and tetrahydrofuran. The antioxidant activities, including free radical scavenging activity and ferric reducing power of the PA extracts were investigated. The synthetic antioxidants BHA and BHT were used as positive controls. The dichloromethane extract of PA showed superior antioxidant properties. The chemical compositions of the extracts were determined by GC–MS, and further proved that the dichloromethane extract had the best antioxidant characteristics.
Source:Journal of Analytical and Applied Pyrolysis
Author(s): Chunhui Ma , Keguan Song , Jinghua Yu , Lei Yang , Chunjian Zhao , Wenjie Wang , Ge Zu , Yuangang Zu
We studied the pyrolysis process and products of Rosmarinus officinalis leaves. Three kinds of plant materials were used: fresh leaves, air-dried leaves, and air-dried leaves after essential oil distillation. The pyroligneous acids (PA) obtained by pyrolyzing the plant materials with different heating powers were extracted with organic solvents, including methanol, ethyl formate, dichloromethane, thiophene and tetrahydrofuran. The antioxidant activities, including free radical scavenging activity and ferric reducing power of the PA extracts were investigated. The synthetic antioxidants BHA and BHT were used as positive controls. The dichloromethane extract of PA showed superior antioxidant properties. The chemical compositions of the extracts were determined by GC–MS, and further proved that the dichloromethane extract had the best antioxidant characteristics.
Thermogravimetric monitoring of oil refinery sludge
15 October 2013,
09:18:44
Publication date: Available online 23
September 2013
Source:Journal of Analytical and Applied Pyrolysis
Author(s): Agustín G. Barneto , Julia Moltó , José Ariza , Juan A. Conesa
The present work has two dimensions: analytical and environmental. On the one hand we proved that thermogravimetric analysis can be used to perform fast characterization of oil refinery sludge. To this end, thermogravimetric curves were deconvoluted by using autocatalytic kinetics to take into account acceleratory phases in a thermal degradation performed in oxygen-containing atmosphere or at high heating rates. Based on thermogravimetric results, oil refinery sludge was modeled in terms of various fractions (pseudo-components) which degrade as major oil cuts. On the other hand, as an alternative to landfill, we have seen that Soxhlet extraction allows recovery almost half of the weight of sludge as a mixture of hydrocarbons, similar to gas-oil, which burns without residue. This ensures both, waste inerting and significant reduction in sludge volume.
Source:Journal of Analytical and Applied Pyrolysis
Author(s): Agustín G. Barneto , Julia Moltó , José Ariza , Juan A. Conesa
The present work has two dimensions: analytical and environmental. On the one hand we proved that thermogravimetric analysis can be used to perform fast characterization of oil refinery sludge. To this end, thermogravimetric curves were deconvoluted by using autocatalytic kinetics to take into account acceleratory phases in a thermal degradation performed in oxygen-containing atmosphere or at high heating rates. Based on thermogravimetric results, oil refinery sludge was modeled in terms of various fractions (pseudo-components) which degrade as major oil cuts. On the other hand, as an alternative to landfill, we have seen that Soxhlet extraction allows recovery almost half of the weight of sludge as a mixture of hydrocarbons, similar to gas-oil, which burns without residue. This ensures both, waste inerting and significant reduction in sludge volume.
Flame retardancy and thermal degradation behaviors of polypropylene composites with novel intumescent flame retardant and manganese dioxide
15 October 2013,
09:18:44
Publication date: Available online 23
September 2013
Source:Journal of Analytical and Applied Pyrolysis
Author(s): Caimin Feng , Yi Zhang , Dong Liang , Siwei Liu , Zhenguo Chi , Jiarui Xu
The flame retardancy and thermal degradation behavior of polypropylene composites containing ammonium polyphosphate (APP), novel charring agent (CNCA-DA) and manganese dioxide (MnO2) were characterized by limiting oxygen index (LOI), UL-94 measurement, cone calorimeter test (CCT), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and energy dispersive spectrometry (EDS). It was found that a small amount of MnO2 could dramatically increase the LOI value, UL rating of the PP/IFR systems, and reduce the combustion parameters of PP/IFR system from CCT test, including peak heat release rate (p-HRR), total heat release (THR), and smoke production rate (SPR). The catalytic effectivity (CAT-EFF) results showed that when 1wt% MnO2 was added, it had the highest CAT-EFF, and could promote the LOI value of the composites from 27.1 to 30.7. The TGA data revealed that MnO2 could change the degradation behavior of the IFR and PP/IFR, improve the thermal stability of the PP/IFR systems at high temperature and increase the char residue. The morphological structures observed by digital photos and SEM indicated that MnO2 could effectively help to form more continuous and compact intumescent char layer on the outer surface to protect the underlying materials from burning. The EDS results illustrated that the existence of MnO2 could promote to remain more P and O in the char layer.
Source:Journal of Analytical and Applied Pyrolysis
Author(s): Caimin Feng , Yi Zhang , Dong Liang , Siwei Liu , Zhenguo Chi , Jiarui Xu
The flame retardancy and thermal degradation behavior of polypropylene composites containing ammonium polyphosphate (APP), novel charring agent (CNCA-DA) and manganese dioxide (MnO2) were characterized by limiting oxygen index (LOI), UL-94 measurement, cone calorimeter test (CCT), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and energy dispersive spectrometry (EDS). It was found that a small amount of MnO2 could dramatically increase the LOI value, UL rating of the PP/IFR systems, and reduce the combustion parameters of PP/IFR system from CCT test, including peak heat release rate (p-HRR), total heat release (THR), and smoke production rate (SPR). The catalytic effectivity (CAT-EFF) results showed that when 1wt% MnO2 was added, it had the highest CAT-EFF, and could promote the LOI value of the composites from 27.1 to 30.7. The TGA data revealed that MnO2 could change the degradation behavior of the IFR and PP/IFR, improve the thermal stability of the PP/IFR systems at high temperature and increase the char residue. The morphological structures observed by digital photos and SEM indicated that MnO2 could effectively help to form more continuous and compact intumescent char layer on the outer surface to protect the underlying materials from burning. The EDS results illustrated that the existence of MnO2 could promote to remain more P and O in the char layer.
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