UV-B exposure （312 nm and 2.5 W.m^-2） caused 50 percent killing m Chlorella at lO mln and complete Killing at oo ram. Nitrate and phosphate uptakes were faster under UV-B irradiation than in fluorescent light. Short...UV-B exposure （312 nm and 2.5 W.m^-2） caused 50 percent killing m Chlorella at lO mln and complete Killing at oo ram. Nitrate and phosphate uptakes were faster under UV-B irradiation than in fluorescent light. Short exposure of UV-B stimulated nitrate and phosphate uptakes but inhibited ammonium uptake. Ammonium uptake was inhibited upto 30 min and thereafter increased and become constant after 60 min UV-B exposure. UV-B stimulated the nitrate uptake in deficient cells. Interestingly, there was rapid stimulation of nitrate uptake in deficient medium after 30 min UV-B treatment. Darkness inhibited the uptake mechanism but the fluorescent light enhanced the rate of nitrate uptake stimulation in deficient cells of Chlorella vulgaris.展开更多
A moving boundary model under considering the volume change of spherical resin beads during ion exchange processes was employed to recognize the mechanisms of recovering uranium from carbonate solutions using strongly...A moving boundary model under considering the volume change of spherical resin beads during ion exchange processes was employed to recognize the mechanisms of recovering uranium from carbonate solutions using strongly basic anion exchanger Two important factors, swelling and ion exchange, which directly affect the volume of ion exchangers were taken into account. An ion exchange mechanism has been found for the forward reaction RCl/[UO2 CO3)3]4- at pH 8.5～10.0, where the rate is controlled by liquid-film diffusion at low concentration of the tetravalent uranyl complex anion [UO2 (CO3)3]4-, and is partical diffusion governing at high concentration of the complex anion. The mechanism of RCl/U(Ⅳ) at pH 5. 5～7. 5 is a chemical reaction taking place at the moving boundary of the unreacted nucleus. For the reverse reaction RnU/NaCl, the uranyl tricarbonate complex anion in the resin phase is replaced by Cl- ions with an ion exchange mechanism always determined by particle diffusion. The other forms of uranium in the solid phase loaded on the resin at pH 5. 5～7. 5 should belong to non-exchangeable uranium. The mechanism of the reverse reaction RnU/HCl is always chemical reaction which is not restricted to the moving boundary of the unreacted core.展开更多
文摘UV-B exposure （312 nm and 2.5 W.m^-2） caused 50 percent killing m Chlorella at lO mln and complete Killing at oo ram. Nitrate and phosphate uptakes were faster under UV-B irradiation than in fluorescent light. Short exposure of UV-B stimulated nitrate and phosphate uptakes but inhibited ammonium uptake. Ammonium uptake was inhibited upto 30 min and thereafter increased and become constant after 60 min UV-B exposure. UV-B stimulated the nitrate uptake in deficient cells. Interestingly, there was rapid stimulation of nitrate uptake in deficient medium after 30 min UV-B treatment. Darkness inhibited the uptake mechanism but the fluorescent light enhanced the rate of nitrate uptake stimulation in deficient cells of Chlorella vulgaris.
文摘A moving boundary model under considering the volume change of spherical resin beads during ion exchange processes was employed to recognize the mechanisms of recovering uranium from carbonate solutions using strongly basic anion exchanger Two important factors, swelling and ion exchange, which directly affect the volume of ion exchangers were taken into account. An ion exchange mechanism has been found for the forward reaction RCl/[UO2 CO3)3]4- at pH 8.5～10.0, where the rate is controlled by liquid-film diffusion at low concentration of the tetravalent uranyl complex anion [UO2 (CO3)3]4-, and is partical diffusion governing at high concentration of the complex anion. The mechanism of RCl/U(Ⅳ) at pH 5. 5～7. 5 is a chemical reaction taking place at the moving boundary of the unreacted nucleus. For the reverse reaction RnU/NaCl, the uranyl tricarbonate complex anion in the resin phase is replaced by Cl- ions with an ion exchange mechanism always determined by particle diffusion. The other forms of uranium in the solid phase loaded on the resin at pH 5. 5～7. 5 should belong to non-exchangeable uranium. The mechanism of the reverse reaction RnU/HCl is always chemical reaction which is not restricted to the moving boundary of the unreacted core.
