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This work presents a first approach concerning the use of Tectona Grandis tree sawdust (from East Timor) for high activated carbon production, by physical activation with carbon dioxide at different temperatures. The activated carbons (AC) obtained exhibit a well-developed porous structure with a pore size distribution varying from micro to mesopores. Selected AC was successfully evaluated for pesticide removal, specific to 4-chloro-2-methylphenoxyacetic acid, from the liquid phase. The results presented are very promising, allowing to establish that Tectona Grandis sawdust is as an excellent precursor for the basic AC production and allow to expect good performance of theses adsorbents on the removal of a broad range of pollutants. It should also be noted that, this achievement is very relevant for developing countries, such East Timor, where Tectona Grandis sawdust is available and may constitute a source of income creating a handle to the technical and industrial development of this region. [ABSTRACT FROM AUTHOR]

Objective of this study was to investigate the mechanisms of 2,4-Dichlorophynoxy acetic acid (2,4-D) sorption on biochar in aqueous solutions. Sorption isotherm, kinetics, and desorption experiments were performed to identify the role of biochars’ feedstock and production conditions on 2,4-D sorption. Biochars were prepared from various green wastes (tea, burcucumber, and hardwood) at two pyrolytic temperatures (400 and 700 °C). The tea waste biochar produced at 700 °C was further activated with steam under a controlled flow. The sorption of 2,4-D was strongly dependent on the biochar properties such as specific surface area, surface functional groups, and microporosity. The steam activated biochar produced from tea waste showed the highest (58.8 mg g −1 ) 2,4-D sorption capacity, which was attributed to the high specific surface area (576 m 2 g −1 ). The mechanism of 2,4-D removal from aqueous solution by biochar is mainly attributed to the formation of heterogeneous sorption sites due to the steam activation. [ABSTRACT FROM AUTHOR]

Abstract: Activated carbons have been prepared by physical activation with H2O–CO2 in two-step pre-treatment including ZnCl2–HCl from acorn shell at 850°C. The active carbons were characterized by N2 adsorption at 77K. Adsorption capacity was demonstrated by the iodine numbers. The surface chemical characteristics of activated carbons were determined by FTIR spectroscopic method. The microstructure of the activated carbons prepared was examined by scanning electron microscopy. The maximum BET surface area of the obtained activated carbon was found to be around 1779m2/g. [Copyright &y& Elsevier]

Abstract: Fibres from oil palm empty fruit bunches, generated in large quantities by palm oil mills, were processed into self-adhesive carbon grains (SACG). Untreated and KOH-treated SACG were converted without binder into green monolith prior to N2-carbonisation and CO2-activation to produce highly porous binderless carbon monolith electrodes for supercapacitor applications. Characterisation of the pore structure of the electrodes revealed a significant advantage from combining the chemical and physical activation processes. The electrochemical measurements of the supercapacitor cells fabricated using these electrodes, using cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge–discharge techniques consistently found that approximately 3h of activation time, achieved via a multi-step heating profile, produced electrodes with a high surface area of 1704m2 g−1 and a total pore volume of 0.889cm3 g−1, corresponding to high values for the specific capacitance, specific energy and specific power of 150Fg−1, 4.297Whkg−1 and 173Wkg−1, respectively. [Copyright &y& Elsevier]

Abstract: In this work a novel biomass precursor for the production of activated carbons (AC) was studied. The lignocellulosic material used as precursor is the coffee bean endocarp, which constitutes an industrial residue from the Portuguese coffee industry. Activation by carbon dioxide and potassium hydroxide produces activated carbons with small external areas and pore volumes up to 0.22 and 0.43cm3 g−1, respectively, for CO2 and KOH activation. All the AC’s produced are very basic in nature with point of zero charge higher than 8. SEM/EDX studies indicate the presence of K, O, Ca and Si. By FTIR it was possible to identify the formation on the AC’s surface of several functional groups, namely phenol, alcohol, quinone, lactone, pyrone and ether as well as Si The tailoring of the porous and chemical structure of the activated carbons produced is possible by selecting the appropriate production conditions. [Copyright &y& Elsevier]

Abstract: A study on the preparation of rice bran-based activated carbon was conducted, with and without an acid treatment step prior the activation process. The influence of the activation time on the structure of the activated carbons was evaluated. The acid treatment had a significant positive influence on sorption properties. The rice bran-activated carbon presented a BET surface area of 652m2 g−1 and a pore volume of 0.137cm3 g−1, with mesopores predominance (ca. 55%). These experimental results indicated the potential use of rice bran as a precursor in the activated carbon preparation process, thus representing an economically promising material. [Copyright &y& Elsevier]