The frequent co-existence of arsenic (As) and lead (Pb) necessitates the investigation of clean-up technologies for multi-metal(loid)s. Field survey and hydroponic experiments were conducted to elucidate the co-accumulation of As and Pb in Pteris vittata L. The P. vittata population isolated from a Pb–Zn mine in Yunnan province, China is a potential extractor of As and Pb co-contamination. Hydroponic experiment found that the highest frond As and Pb concentrations in mining population of P. vittata reached 12.2 and 0.99 g kg?1, respectively. The interaction between As and Pb in P. vittata was further more disclosed. Pb (2 mg L?1) improved the frond As concentration by 60 to 150 % in mining populations of P. vittata. Micro-X-ray absorption spectroscopy indicated that under the combined exposure of As and Pb, the As content in the rhizoid epidermis increased by about 10-fold, and the As(V) percentage increased in each rhizoid tissue, as compared with that under As exposure alone. The co-absorption of As and Pb on the epidermis and the enhanced transportation of As(V) from epidermis into the rhizoid were suggested to contribute to the increased As accumulation. 相似文献
A biotrickling filter inoculated with commercial mixed microorganisms B350 was employed to treat N-containing odorous vapor - aniline. Results indicated no aniline could be detected when empty bed residence time (EBRT) was larger than 110s at inlet concentration of 0.30 g m(-3). The variation of inlet concentration did not change removal efficiencies when concentration is less than 0.21 g m(-3) at fixed EBRT 110s. Biodegradation mechanism of aniline was tentatively proposed based on identified intermediates and predicted biodegradation pathway as well as final mineralized products. Aniline was firstly biodegraded to catechol, and then to levulinic acid and subsequently to succinic acid. Finally, about 62% aniline carbon was completely mineralized to CO(2), while about 91% aniline nitrogen was converted into ammonia and nitrate. Bacterial community in biotrickling filter was found that at least seven bands microbes were identified for high efficiencies of bioreactor at stable state. In all, biotrickling filter seeded with B350 would be a better choice for the purification odorous gas containing high concentration aniline. 相似文献
In this present study, adsorptive membranes for Cr(VI) ion removal were prepared by blending polyethersulfone (PES) with hydrous ferric oxide (HFO) nanoparticles (NPs). The effects of HFO NPs to PES weight ratio (0–1.5) on the physicochemical properties of the resultant HFO/PES adsorptive membranes were investigated with respect to the surface chemistry and roughness as well as structural morphologies using different analytical instruments. The adsorptive performance of the HFO NPs/PES membranes was studied via batch adsorption experiments under various conditions by varying solution pH, initial concentration of Cr(VI), and contact time. The results showed that the membrane made of HFO/PES at a weight ratio of 1.0 exhibited the highest adsorption capacity which is 13.5 mg/g. Isotherm and kinetic studies revealed that the mechanism is best fitted to the Langmuir model and pseudo-second-order model. For filtration of Cr(VI), the best promising membranes showed improved water flux (629.3 L/m2 h) with Cr(VI) ion removal of 75%. More importantly, the newly developed membrane maintained the Cr(VI) concentration below the maximum contamination level (MCL) for up to 9 h.