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As biomass wastes, Arundo donax Linn and pomelo peel were used as precursors for activated carbons (ALAC and PPAC) preparation by phosphoric acid activation. The pore structure and surface acidic functional groups of both carbons were characterized by nitrogen adsorption/desorption experiment, NH 3 -temperature-programmed desorption (NH 3 -TPD) and Fourier transform infrared spectroscopy (FTIR). A batch of experiments was carried out to investigate the adsorption performances of ciprofloxacin under different conditions. Results showed that PPAC exhibited larger surface area (1252 m 2 /g) and larger portion of mesoporous, while ALAC was typical of microporous materials. Results from NH 3 -TPD suggested that ALAC was characteristic of more acidic functional group than PPAC. The maximum monolayer adsorption capability was 244 mg/g for ALAC and 400 mg/L for PPAC. Kinetics studies showed intra-particle diffusion was not the unique rate-controlling step. Boundary layer resistance existed between adsorbent and adsorbate. [ABSTRACT FROM AUTHOR]

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]