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Abstract: Effects of different pretreatment protocols in (NH4)2HPO4 activation of rice straw on porous activated carbon evolution were evaluated. The pore structure, morphology and surface chemistry of obtained activated carbons were investigated by nitrogen adsorption, scanning electron microscopy and Fourier transform infrared spectroscopy. It was found that pretreatment combining impregnation with (NH4)2HPO4 and preoxidation could significantly affect the physicochemical properties of prepared activated carbons. The apparent surface area and total pore volume as high as 1154m2/g and 0.670cm3/g were obtained respectively, when combined process of impregnation followed by preoxidation at 200°C and activation at 700°C was carried out. Meanwhile, the activated carbon yield and maximum methylene blue adsorption capacity up to 41.14% and 129.5mg/g were achieved, respectively. The results exhibited that (NH4)2HPO4 could be an effective activating agent for producing activated carbons from rice straw. [ABSTRACT FROM AUTHOR]

The interaction of CH2I2 and CH2ICl with 60 fs laser pulses at 800 and 400 nm has been studied using TOF-MS. Molecular detachment of I2+ and ClI+ are observed. The generation of I2+ and ClI+ can be understood by a concerted elimination mechanism. The kinetic energy released is estimated from the peak splitting of I2+ obtained in the TOF-MS, originated from Coulomb explosion. According to the results, multiphoton ionization is excluded from the possible mechanisms. The observed phenomena are attributed to the interaction of the intense laser field with the molecular potential energy surfaces. [Copyright &y& Elsevier]