In most developing countries, particularly in the countries of sub-Saharan Africa, corn cobs are considered as waste polluting the environment during the harvest period of this cereal. In order to valorize this agricu...In most developing countries, particularly in the countries of sub-Saharan Africa, corn cobs are considered as waste polluting the environment during the harvest period of this cereal. In order to valorize this agricultural waste, high-performance, inexpensive and low-energy consumption magnetic bioadsorbents were prepared from corn cobs. The chemically activated raw corn cob was magnetized by coating the surface with magnetite nanoparticles. The prepared biosorbents were characterized by FT-IR, XRD, FE-SEM associated with EDX, HR-TEM, TG analysis, BET surface area analysis and XPS. The maximum specific surface area of 35.22 m<sup>2</sup>/g was reached. An attempt to use of these magnetic biosorbents for the removal of heavy metal like Cr(VI) from aqueous solution was envisaged.展开更多
The objective of this work is to prepare one of the best activated carbon (CA) based on wood (Acacia auriculeaformis). The chemical activation method was used for varying the chemical agent namely phosphoric acid H3PO...The objective of this work is to prepare one of the best activated carbon (CA) based on wood (Acacia auriculeaformis). The chemical activation method was used for varying the chemical agent namely phosphoric acid H3PO4 (CAA), sodium hydroxide NaOH (CAB), and sodium chloride NaCl (CAS). The physico-chemical analysis of the three activated carbons indicated that, under the conditions of preparation, the activated carbons possess activation efficiencies lower than 50% (41.81% for CAA, 26.25% for CAB and 48.87% for CAS), low ash content (CAA: 5.00%, CAB: 14.90 and CAS: 6.60%) and iodine values ranging from 190.35 mg/g to 380.71 mg/g, suggesting that the good quality of the prepared activated carbon. The surface functional groups using Boehm test and the zero point charge (pHZPC) methods confirmed the acidic, basic and neutral character for CAA, CAB and CAS respectively (CAA: pHZPC = 4.8, CAB: pHZPC = 8.2, CAS: pHZPC = 6.8). The surface specific areas were determined through the liquid phase adsorption of acetic acid and methylene blue using the Langmuir method and BET analysis. Also, the porosity was determined. The BET surface areas of CAA, CAB and CAS were respectively 561.60 m2/g, 265.00 m2/g and 395.40 m2/g. The influence of chemical activation agent on pores formation was confirmed by scanning electron microscopic (SEM) analysis. CAA was selected as the best activated carbon because of its good surface area and good pore volume compared to those found in the literature. Therefore, its application as an adsorbent for effluents treatment could be explored. In addition, the best activating agent for coal from Acacia auriculeaformis was found to be phosphoric acid.展开更多
In this work, low cost coconut biochar based activated carbon (CBAC) was used for adsorption of Butylparaben (BPB) from aqueous medium. The prepared CBAC was characterized using BET, Boehm analysis and the adsorption ...In this work, low cost coconut biochar based activated carbon (CBAC) was used for adsorption of Butylparaben (BPB) from aqueous medium. The prepared CBAC was characterized using BET, Boehm analysis and the adsorption equilibrium, kinetics and thermodynamics studies of BPB adsorption were carried out. During batch adsorption runs, the effects of factors, such as contact time (0 - 300 min), CBAC dose (200 - 800 mg), pH (3 - 11) and solution temperatures (303 - 348 K) were investigated on BPB removal. Experimental results reveal that the BPB removal efficiency on CBAC is higher than 97% under acidic and neutral conditions. Equilibrium data were fitted by Langmuir, Freundlich and Temkin isotherm models with correlation coefficient more than 0.9. The pseudo-second order kinetic model was observed to fit well the adsorption data. Thermodynamic analysis shows positive values of standard Gibb’s free energy, suggesting the non-spontaneity of the process. The changes in enthalpy (0.2 J.mol-1) and entropy (19 J.mol-1) were found to be endothermic with an increase of randomness. The high adsorption efficiency of the synthesized coconut biochar materials with low cost indicates that it may be a promising adsorbent for removing organic compounds.展开更多
文摘In most developing countries, particularly in the countries of sub-Saharan Africa, corn cobs are considered as waste polluting the environment during the harvest period of this cereal. In order to valorize this agricultural waste, high-performance, inexpensive and low-energy consumption magnetic bioadsorbents were prepared from corn cobs. The chemically activated raw corn cob was magnetized by coating the surface with magnetite nanoparticles. The prepared biosorbents were characterized by FT-IR, XRD, FE-SEM associated with EDX, HR-TEM, TG analysis, BET surface area analysis and XPS. The maximum specific surface area of 35.22 m<sup>2</sup>/g was reached. An attempt to use of these magnetic biosorbents for the removal of heavy metal like Cr(VI) from aqueous solution was envisaged.
文摘The objective of this work is to prepare one of the best activated carbon (CA) based on wood (Acacia auriculeaformis). The chemical activation method was used for varying the chemical agent namely phosphoric acid H3PO4 (CAA), sodium hydroxide NaOH (CAB), and sodium chloride NaCl (CAS). The physico-chemical analysis of the three activated carbons indicated that, under the conditions of preparation, the activated carbons possess activation efficiencies lower than 50% (41.81% for CAA, 26.25% for CAB and 48.87% for CAS), low ash content (CAA: 5.00%, CAB: 14.90 and CAS: 6.60%) and iodine values ranging from 190.35 mg/g to 380.71 mg/g, suggesting that the good quality of the prepared activated carbon. The surface functional groups using Boehm test and the zero point charge (pHZPC) methods confirmed the acidic, basic and neutral character for CAA, CAB and CAS respectively (CAA: pHZPC = 4.8, CAB: pHZPC = 8.2, CAS: pHZPC = 6.8). The surface specific areas were determined through the liquid phase adsorption of acetic acid and methylene blue using the Langmuir method and BET analysis. Also, the porosity was determined. The BET surface areas of CAA, CAB and CAS were respectively 561.60 m2/g, 265.00 m2/g and 395.40 m2/g. The influence of chemical activation agent on pores formation was confirmed by scanning electron microscopic (SEM) analysis. CAA was selected as the best activated carbon because of its good surface area and good pore volume compared to those found in the literature. Therefore, its application as an adsorbent for effluents treatment could be explored. In addition, the best activating agent for coal from Acacia auriculeaformis was found to be phosphoric acid.
文摘In this work, low cost coconut biochar based activated carbon (CBAC) was used for adsorption of Butylparaben (BPB) from aqueous medium. The prepared CBAC was characterized using BET, Boehm analysis and the adsorption equilibrium, kinetics and thermodynamics studies of BPB adsorption were carried out. During batch adsorption runs, the effects of factors, such as contact time (0 - 300 min), CBAC dose (200 - 800 mg), pH (3 - 11) and solution temperatures (303 - 348 K) were investigated on BPB removal. Experimental results reveal that the BPB removal efficiency on CBAC is higher than 97% under acidic and neutral conditions. Equilibrium data were fitted by Langmuir, Freundlich and Temkin isotherm models with correlation coefficient more than 0.9. The pseudo-second order kinetic model was observed to fit well the adsorption data. Thermodynamic analysis shows positive values of standard Gibb’s free energy, suggesting the non-spontaneity of the process. The changes in enthalpy (0.2 J.mol-1) and entropy (19 J.mol-1) were found to be endothermic with an increase of randomness. The high adsorption efficiency of the synthesized coconut biochar materials with low cost indicates that it may be a promising adsorbent for removing organic compounds.
