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Highlights: [•] FeCl3, AlCl3 and MnCl2 were used as the assisted activator to produce carbons. [•] Doping with MnCl2 was favorable for the enlargement of activated carbon. [•] The assisted activator had good performance for holding more fixed carbon. [•] The maximum adsorption capacities followed the order of AC-Fe>AC-Al>AC-Mn>AC. [•] The XPS analysis was used to confirm the adsorption/transformation mechanism. [Copyright &y& Elsevier]

Abstract: The pore structure, chemical properties and adsorption behavior of activated carbons (ACs) derived from Arundo donax Linn using H4P2O7 activation by conventional (AAC) and microwave heating methods (MAAC) were compared. AAC was produced by carbonizing/activating at 600°C for 1h in a muffle furnace. MAAC was prepared with radiation power of 700W and radiation time of 15min. N2 adsorption/desorption isotherms, Boehm titration, Fourier-transform infrared spectroscopy (FTIR) and adsorption capacity of ciprofloxacin (CIP) were used for this purpose. MAAC exhibited larger surface area (1567m2/g) and larger micropore surface area (631m2/g). Results from Boehm’s titration and Fourier-transform infrared spectra suggested that AAC was characteristic of more acidic functionalities than MAAC. It was shown that AAC presented better performance for CIP adsorption per unit surface area. The influence of the textural and surface properties of the adsorbents on the CIP adsorption was discussed. [Copyright &y& Elsevier]

Abstract: The paper presents advantages and limitations of microwave heating in preparation of lotus stalk-based activated carbon by comparing the characteristic and adsorption properties of carbons with microwave (Mic-LSAC) and conventional (LSAC) heating methods employing H3PO4 as chemical agent. Mic-LSAC was produced with radiation power of 700W and radiation time of 15min. LSAC was allowed by single step to get carbonized at 450°C in a muffle furnace for 1h. Both produced carbons showed typical Type IV nitrogen adsorption isotherms. Mic-LSAC had large surface area of 1434m2/g and micropore volume of 1.337cm3/g, while LSAC had surface area of 1220m2/g and micropore volume of 1.191cm3/g. Moreover, Mic-LSAC had higher portion of mesopores than LSAC. Boehm''s titration results and Fourier transform infrared spectra indicated that Mic-LSAC possessed smaller acidic oxygen functionalities. Mic-LSAC had higher pHpzc, more ordered stacking of layer compared to LSAC. For both adsorbents, the adsorption kinetics followed the pseudo-second-order model and the adsorption equilibrium data were very well represented by the Langmuir isotherm. The maximum adsorption capacities obtained at pH 2.80 were 564.97mg/g and 537.63mg/g for Mic-LSAC and LSAC, respectively. The differences of textual and chemical characteristics caused by heating method were related to adsorption capacity. [Copyright &y& Elsevier]