The objective of this study is to develop carbon, that of <i></span><i><span style="font-family:Verdana;">Acacia auriculeaformis</span></i><span style="font-family...The objective of this study is to develop carbon, that of <i></span><i><span style="font-family:Verdana;">Acacia auriculeaformis</span></i><span style="font-family:Verdana;"></i></span><span style="font-family:Verdana;"> through its activation in order to eliminate lead in an aqueous medium. A series of activated carbon has been prepared by chemical activation with phosphoric acid, sodium hydroxide and sodium chloride. The determi</span><span style="font-family:Verdana;">nation of the physico-chemical properties of the prepared carbon guided the choice of phosphoric acid activated carbon as the best adsorbent for the</span><span style="font-family:Verdana;"> elimination of lead(II) in </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">an </span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">aqueous solution. Pb</span><sup><span style="font-family:Verdana;">2+</span></sup><span style="font-family:Verdana;"> adsorption tests in batch mode have shown that the adsorption capacity is influenced by various parameters such as mass, pH, concentration of Pb<sup>2+</sup> ions and contact time linked to the medium and the adsorbent. Adsorption isotherms, kinetic models and thermodynamics have been used to describe the adsorption process. The equilibrium data for activated charcoal correspond well to the model of Freundlich, </span><span style="font-family:Verdana;">Langmuir, Temkin and Kiselev. The kinetic adsorption data proved to be </span><span style="font-family:Verdana;">better described by the pseudo-second order model with </span><span style="font-family:Verdana;">external and intraparticle diffusion which are two decisive steps in the</span><span style="font-family:Verdana;"> adsorption process of Pb<sup>2+</sup> ions. Thermodynamics and adsorption isotherms predict a spontaneous exothermic surface reaction, of the chemisorption type, with ion </span><span><span style="font-family:Verdana;">retention in orderly monolayers on the heterogeneous surface of the adsorbent. Tests carried out with this adsorbent material have contributed to the elimination of the Pb</span><sup><span style="font-family:Verdana;">2+</span></sup><span style="font-family:Verdana;"> ions contained in an industrial effluent with a </span></span><span style="font-family:Verdana;">reduction rate reaching 42.52% against 85.90% in a synthetic solution.展开更多
Dried kelp is one of the most important Japanese foods mainly used as base ingredient. Holdfasts, or rhizoids, of kelp are usually discarded, as rocks, shells, ropes and other contaminants are entangled among them. Th...Dried kelp is one of the most important Japanese foods mainly used as base ingredient. Holdfasts, or rhizoids, of kelp are usually discarded, as rocks, shells, ropes and other contaminants are entangled among them. The purpose of the present study was to examine whether the preparation of activated carbon from holdfasts of <em>Saccharina japonica</em>, a popular kelp harvested in Japan, is possible by a chemical activation technique utilizing zinc chloride, and to study the influence of the process parameters, such as carbonization temperature and the composition of the activator. Under the examined experimental conditions, maximum specific surface area of 1.7 × 10<sup>3</sup> m<sup>2</sup>/g, larger than that of a commercial activated carbon, was observed at 600℃ and the zinc chloride composition of 75 mass%.展开更多
The uptake of tartrazine from its aqueous solution by powdered activated carbon prepared from cola nut shells chemically activated with potassium hydroxide (ACK) and phosphoric acid (ACP) has been investigated using k...The uptake of tartrazine from its aqueous solution by powdered activated carbon prepared from cola nut shells chemically activated with potassium hydroxide (ACK) and phosphoric acid (ACP) has been investigated using kinetics models. Batch isotherm data were analysed with the pseudo-first order, pseudo-second order model as well as the intraparticle diffusion model. For structural elucidation, the materials were characterized using FTIR, XRD and SEM. These analyses revealed that the activated carbons (ACK and ACP) were predominantly mesoporous with several oxygen-containing functional groups dispersed on their surface. The reaction was systematically investigated under various experimental conditions such as contact time, adsorbent dose and pH. For the two adsorbents, the quantity adsorbed of 19.256 mg/g and 18.196 mg/g respectively for ACP and ACK at respective contact times of 5 and 10 min were obtained. The adsorption data were tested with the Langmuir, Freundlich models. Langmuir model was found to best describe the adsorption of tartrate ions with maximum monolayer adsorption capacities of 24.57 and 21.59 mg/g for ACP and ACK, respectively. Results analysis indicated clearly that the pseudo-second order kinetic rate model best fitted the experimental data and therefore was the adsorption controlling mechanism for both adsorbents. Thermodynamic studies revealed that the adsorption process was spontaneous and exothermic for ACP with increased randomness at the solid solution interface, then exothermic but non-spontaneous for ACK. The results show that these activated carbons could be an alternative for more costly adsorbents for the purpose of tartrate ions elimination.展开更多
Post-consumer polymeric wastes in form of low-density polyethylene (LDPE) can now be considered suitable as a precursor for the synthesis of low-cost activated carbon (AC). This study produced AC from LDPE using sulph...Post-consumer polymeric wastes in form of low-density polyethylene (LDPE) can now be considered suitable as a precursor for the synthesis of low-cost activated carbon (AC). This study produced AC from LDPE using sulphuric acid (H<sub>2</sub>SO<sub>4</sub>) and potassium hydroxide (KOH) as the activating agent. The reaction conditions for pyrolysis were varied in the range of 0.50 - 2.00 M, 400<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#ffffff;"="">°</span>C - 500<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#ffffff;"="">°</span>C, and 45 - 60 minutes. Physico-chemical investigations reveal that AC yield is significantly dependent on both carbonization temperatures and time. The obtained optimum values of 446.50<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#ffffff;"="">°</span>C and 51.09 mins gave a yield of 24% for the base-activated carbon. The high iodine numbers obtained strongly indicate the presence of large surface area and pore volumes is further confirmed using the Scanning Electron Microscopy (SEM) analysis which reveals the presence of pores on the external surface of the carbons. Fourier Transform Infrared Technique (FTIR) analysis further shows that the synthesized compounds are purely carbon with rich oxy-gen-surface complexes on the surface which is as a result of the introduction of the chemical oxidizing agents. The produced carbons were found to have high adsorption affinity for selected inorganic ions which are: Mn<sup>7+</sup>, Co<sup>2+</sup>, and Cr<sup>6+</sup>. Adsorption isotherm results show the adsorption process to be favourable with the Langmuir isotherm parameter RL having values of <1, while the Freudlich adsorption model was found to perfectly fit the data at selected adsorbent dosages and adsorbate concentrations. The pseu-do-second-order model provides the best correlation for the kinetic analy展开更多
With the increasing demand of sustainable and eco-friendly resources,it is very attractive to use waste leaves for activated carbon(AC)preparation that can be used in supercapacitors.Considering the practically collec...With the increasing demand of sustainable and eco-friendly resources,it is very attractive to use waste leaves for activated carbon(AC)preparation that can be used in supercapacitors.Considering the practically collected leaves are commonly in mixed nature,and extra efforts are needed to sort these mixtures,we here report the first preparation of AC using mixed leaves from different plants,including Platanus acerifolia(PA),Firmiana platanifolia(FP)and Pistia stratiotes(PS),and compared the results with single leaves-derived AC materials.These leave-derived AC samples were characterized with FESEM,EDS,FTIR and Raman spectroscopy,and electrochemical tests.The AC derived from mixed leaves(PA3FP1PS2AC)showed a good specific capacitance of 246 F·g−1 at 1 A·g−1 in aqueous 3 mol·L^(-1)KOH.This sample further showed the largest specific capacitance of 201 F·g−1 at 5 A·g−1,as compared with the non-mixed AC samples,and a good stability of 100.0%capacitance retention over 1000 cycles.Utilizing mixed leaves for AC preparation is not only demonstrated to be a promising approach of low cost and high-performance AC production for supercapacitor applications,but may also help environmental protection by reducing the invasive species problem.展开更多
文摘The objective of this study is to develop carbon, that of <i></span><i><span style="font-family:Verdana;">Acacia auriculeaformis</span></i><span style="font-family:Verdana;"></i></span><span style="font-family:Verdana;"> through its activation in order to eliminate lead in an aqueous medium. A series of activated carbon has been prepared by chemical activation with phosphoric acid, sodium hydroxide and sodium chloride. The determi</span><span style="font-family:Verdana;">nation of the physico-chemical properties of the prepared carbon guided the choice of phosphoric acid activated carbon as the best adsorbent for the</span><span style="font-family:Verdana;"> elimination of lead(II) in </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">an </span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">aqueous solution. Pb</span><sup><span style="font-family:Verdana;">2+</span></sup><span style="font-family:Verdana;"> adsorption tests in batch mode have shown that the adsorption capacity is influenced by various parameters such as mass, pH, concentration of Pb<sup>2+</sup> ions and contact time linked to the medium and the adsorbent. Adsorption isotherms, kinetic models and thermodynamics have been used to describe the adsorption process. The equilibrium data for activated charcoal correspond well to the model of Freundlich, </span><span style="font-family:Verdana;">Langmuir, Temkin and Kiselev. The kinetic adsorption data proved to be </span><span style="font-family:Verdana;">better described by the pseudo-second order model with </span><span style="font-family:Verdana;">external and intraparticle diffusion which are two decisive steps in the</span><span style="font-family:Verdana;"> adsorption process of Pb<sup>2+</sup> ions. Thermodynamics and adsorption isotherms predict a spontaneous exothermic surface reaction, of the chemisorption type, with ion </span><span><span style="font-family:Verdana;">retention in orderly monolayers on the heterogeneous surface of the adsorbent. Tests carried out with this adsorbent material have contributed to the elimination of the Pb</span><sup><span style="font-family:Verdana;">2+</span></sup><span style="font-family:Verdana;"> ions contained in an industrial effluent with a </span></span><span style="font-family:Verdana;">reduction rate reaching 42.52% against 85.90% in a synthetic solution.
文摘Dried kelp is one of the most important Japanese foods mainly used as base ingredient. Holdfasts, or rhizoids, of kelp are usually discarded, as rocks, shells, ropes and other contaminants are entangled among them. The purpose of the present study was to examine whether the preparation of activated carbon from holdfasts of <em>Saccharina japonica</em>, a popular kelp harvested in Japan, is possible by a chemical activation technique utilizing zinc chloride, and to study the influence of the process parameters, such as carbonization temperature and the composition of the activator. Under the examined experimental conditions, maximum specific surface area of 1.7 × 10<sup>3</sup> m<sup>2</sup>/g, larger than that of a commercial activated carbon, was observed at 600℃ and the zinc chloride composition of 75 mass%.
文摘The uptake of tartrazine from its aqueous solution by powdered activated carbon prepared from cola nut shells chemically activated with potassium hydroxide (ACK) and phosphoric acid (ACP) has been investigated using kinetics models. Batch isotherm data were analysed with the pseudo-first order, pseudo-second order model as well as the intraparticle diffusion model. For structural elucidation, the materials were characterized using FTIR, XRD and SEM. These analyses revealed that the activated carbons (ACK and ACP) were predominantly mesoporous with several oxygen-containing functional groups dispersed on their surface. The reaction was systematically investigated under various experimental conditions such as contact time, adsorbent dose and pH. For the two adsorbents, the quantity adsorbed of 19.256 mg/g and 18.196 mg/g respectively for ACP and ACK at respective contact times of 5 and 10 min were obtained. The adsorption data were tested with the Langmuir, Freundlich models. Langmuir model was found to best describe the adsorption of tartrate ions with maximum monolayer adsorption capacities of 24.57 and 21.59 mg/g for ACP and ACK, respectively. Results analysis indicated clearly that the pseudo-second order kinetic rate model best fitted the experimental data and therefore was the adsorption controlling mechanism for both adsorbents. Thermodynamic studies revealed that the adsorption process was spontaneous and exothermic for ACP with increased randomness at the solid solution interface, then exothermic but non-spontaneous for ACK. The results show that these activated carbons could be an alternative for more costly adsorbents for the purpose of tartrate ions elimination.
文摘Post-consumer polymeric wastes in form of low-density polyethylene (LDPE) can now be considered suitable as a precursor for the synthesis of low-cost activated carbon (AC). This study produced AC from LDPE using sulphuric acid (H<sub>2</sub>SO<sub>4</sub>) and potassium hydroxide (KOH) as the activating agent. The reaction conditions for pyrolysis were varied in the range of 0.50 - 2.00 M, 400<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#ffffff;"="">°</span>C - 500<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#ffffff;"="">°</span>C, and 45 - 60 minutes. Physico-chemical investigations reveal that AC yield is significantly dependent on both carbonization temperatures and time. The obtained optimum values of 446.50<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#ffffff;"="">°</span>C and 51.09 mins gave a yield of 24% for the base-activated carbon. The high iodine numbers obtained strongly indicate the presence of large surface area and pore volumes is further confirmed using the Scanning Electron Microscopy (SEM) analysis which reveals the presence of pores on the external surface of the carbons. Fourier Transform Infrared Technique (FTIR) analysis further shows that the synthesized compounds are purely carbon with rich oxy-gen-surface complexes on the surface which is as a result of the introduction of the chemical oxidizing agents. The produced carbons were found to have high adsorption affinity for selected inorganic ions which are: Mn<sup>7+</sup>, Co<sup>2+</sup>, and Cr<sup>6+</sup>. Adsorption isotherm results show the adsorption process to be favourable with the Langmuir isotherm parameter RL having values of <1, while the Freudlich adsorption model was found to perfectly fit the data at selected adsorbent dosages and adsorbate concentrations. The pseu-do-second-order model provides the best correlation for the kinetic analy
基金supports for this work from the National Natural Science Foundation of China(21873000)Shanghai Ledding Adenil Dislipline Project(B302)the Shanghai Key Laboratory Project(08DZ2230500).
文摘With the increasing demand of sustainable and eco-friendly resources,it is very attractive to use waste leaves for activated carbon(AC)preparation that can be used in supercapacitors.Considering the practically collected leaves are commonly in mixed nature,and extra efforts are needed to sort these mixtures,we here report the first preparation of AC using mixed leaves from different plants,including Platanus acerifolia(PA),Firmiana platanifolia(FP)and Pistia stratiotes(PS),and compared the results with single leaves-derived AC materials.These leave-derived AC samples were characterized with FESEM,EDS,FTIR and Raman spectroscopy,and electrochemical tests.The AC derived from mixed leaves(PA3FP1PS2AC)showed a good specific capacitance of 246 F·g−1 at 1 A·g−1 in aqueous 3 mol·L^(-1)KOH.This sample further showed the largest specific capacitance of 201 F·g−1 at 5 A·g−1,as compared with the non-mixed AC samples,and a good stability of 100.0%capacitance retention over 1000 cycles.Utilizing mixed leaves for AC preparation is not only demonstrated to be a promising approach of low cost and high-performance AC production for supercapacitor applications,but may also help environmental protection by reducing the invasive species problem.