Ozonation can modify the surface property of an activated carbon such as specific surface area, pore volume, and functional group. Results indicate that ozonation can increase the specific surface area of an activated carbon from 783+/-51 to 851+/-25 m2/g due in part to increasing micropores (those below 15 A). However, there is no change in macropore and mesopore upon ozonation. The amount of oxygen functional group (OFG) increases from 197+/-4 to 240+/-4 microeq/g, mostly in hydroxyl and carboxyl groups upon ozone treatment. These oxygen-containing functional groups are stable in the temperature range 30-250 degrees C, but begin to decompose when temperature increases beyond 300 and 350 degrees C. When the temperature reaches 1200 degrees C, all OFGs virtually disappear. The effect of ozone treatment on the adsorption of volatile organic carbon (VOC) was exemplified by methylethylketone (MEK) and benzene. The adsorption density of MEK and benzene by ozone treated activated carbon (AC(O3)) are greater than that by the untreated (AC), with MEK being more adsorbable than benzene. Results of factorial analysis indicate that physical characteristics, namely, micropore, BET surface area, pore diameter (PD), micropore volume (MV) play an important role on benzene and MEK adsorption. 相似文献
Although xanthate addition can be used for treating copper-containing wastewater, a better understanding of the leaching toxicity and the stability characteristics of the copper xanthate complexes formed is essential. This work was undertaken to evaluate the leaching behavior of copper xanthate complex precipitates by means of toxicity characteristics leaching procedure (TCLP) and semi-dynamic leaching test (SDLT) using 1 N acetic acid solution as the leachant. Also, the chemical stability of the copper xanthate complex during extraction has been examined with the studying of variation of chemical structure using UV-vis, Fourier transform infrared and X-ray photoelectron spectroscopies (XPS).Both TCLP and SDLT results showed that a negligible amount of copper ion was leached out from the copper xanthate complex precipitate, indicating that the complex exhibited a high degree of copper leaching stability under acidic conditions. Nevertheless, chemical structure of the copper xanthate complex precipitate varied during the leaching tests. XPS data suggested that the copper xanthate complex initially contained both cupric and cuprous xanthate, but the unstable cupric xanthate change to the cuprous form after acid extraction, indicating the cuprous xanthate to be the final stabilizing structure. Despite that, the changes of chemical structure did not induce the rapid leaching of copper from the copper xanthate complex. 相似文献
Objective: Bicycle riding is increasingly popular in Taiwan, but the number of cyclists injured and cyclists' death rates are both increasing. The aim of this study was to investigate the different characteristics and clinical outcomes of traffic accident–related head injuries among cyclists in urban and rural areas.
Methods: Records of 812 patients (533 urban and 279 rural) admitted to 27 hospitals in Taipei City and Hualien County as the result of a traumatic head injury while bicycling between 1998 and 2013 were retrieved for study. Demographics, details about the accident, protective helmet use, and clinical outcomes were then subjected to analysis.
Results: Urban victims were more likely to be injured during morning and early evening rush hours and rural victims during the day; most urban victims were between 19 and 34 years of age and injured in the slow lane; rural victims tended to be younger or older and were injured in the fast lane (all P ≤.001). Riders who wore a helmet were less likely to suffer loss of consciousness (odds ratio [OR] = 0.31), amnesia (OR = 0.069), neurological disorders (OR = 0.205), or facial fractures (OR = 0.369). Older age, more severe head injuries, and bicycle–motor vehicle collisions influenced the severity of symptoms on admission and the residual effects at discharge.
Conclusions: Differences in the characteristics of injuries in urban and rural areas and the utilization of protective helmets may help government authorities adopt appropriate policies to promote safer and more enjoyable cycling. 相似文献
The reproductive biology of spiny lobster, Panulirus penicillatus, was studied based on 2,068 lobsters, ranging from 34.28 to 131.60 mm carapace length (CL), sampled in Taitung coastal waters
from September 2003 to December 2004. The overall sex ratio approximated 1:1 (χ2 = 0.02, P > 0.05), but the monthly sex ratios in 2004 showed significant differences and males were predominant in sizes larger than
80 mm CL. Reproductive activity, assessed using histology, a gonadosomatic index and percentage of ovigerous females, indicated
that the mature females could be found in every month and that the major spawning occurred from May to September. The presence
of re-developing/re-ripe ovaries by month and size-specific spawning time suggest that larger mature females (>60 mm CL) spawn
at least three times a year while smaller new mature females spawn at least once a year. For females, the estimated sizes
at 50% physiological and functional maturity were (mean ± SE) 56.46 ± 0.56 mm CL and 66.63 ± 1.07 mm CL. The estimated sizes
at functional maturity were between 72 and 74 mm CL for males. The number of eggs per spawning event (brood size, BS) was
related to CL by the equation YBS = 2.4 × 10-3CL4.18 (r2 = 0.902, n = 12). Female lobsters with CL ranging from 60 to 80 mm made the greatest contributions to egg production because of their
high brood size and active reproductive activity. A minimum legal size should be established for the fishery to protect egg
production potential of lobster population in the southeastern coastal waters off Taiwan. 相似文献
This study surveyed emissions from 2- and 4-stroke new and in-use motorcycles. Emission tests were carried out on a dynamometer following the designated test procedure of the Economic Commission for Europe (ECE). Samples were derived during various driving stages, which included idle, acceleration, 30 km/hr cruise, 50 km/hr cruise, and deceleration. All test motorcycles (10 new and 15 in-use) complied with Taiwan Environmental Protection Administration's Phase III Motorcycle Emission Standards. The dominant volatile organic carbon (VOC) species were isopentane (53 and 295 mg/km, 2- and 4-stroke, respectively), 2-methylpentane (75 and 83 mg/km), 3-methylpentane (34 and 66 mg/km), and toluene (30 and 100 mg/km). The VOC emission factors for the 2-/4-stroke motorcycles were 311/344 (new) and 1479/433 (in-use) mg/km, respectively. In addition, the dominant carbonyl species for the new and in-use motorcycles were formaldehyde (0.4 and 0.7 mg/km, respectively), acetaldehyde (0.6 and 1.2 mg/km), and acetone (0.5 and 0.7 mg/km). The carbonyl compound emission factors for the 2- and 4-stroke motorcycles were 3.2/3.1 (new) and 5.3/4.6 (in-use) mg/km, respectively. The ozone formation potentials, based on an ECE test cycle, show that the values from the in-use motorcycles were higher than those from the new motorcycles. The dominant VOC species for the ozone formation potential were propylene (65 and 502 mg-O3/km, respectively), isopentane (98 and 501 mg-O3/km), 2-methylpentane (152 and 167 mg-O3/ km), 3-methylpentane (79 and 253 mg-O3/km), and toluene (127 and 398 mg-O3/km). Further, the dominant carbonyl species were formaldehyde (4.1 and 6.2 mg-O3/ km, new and in-use, respectively) and acetaldehyde (4.8 and 9 mg-O3/km). 相似文献
Adsorption performance of activated carbon adsorbers in the downstream duct of vehicle spray painting booths has been studied to understand whether fine paint particles in the off-gas would deteriorate the adsorption capacity of volatile organic compounds (VOCs) on activated carbons. Three forms of activated carbons were selected and their properties were determined using nitrogen adsorption analysis, the measurement of pH value and total ash content, energy dispersion spectrometer, field-emission scanning electron microscopy, and thermogravimetric analysis. Results show that the adsorption capacity of activated carbon strongly depends upon its available specific surface area. When the total uptake on activated carbon approaches saturation, the vapors adsorbed would commence to get displaced by the paint particles gradually as time elapses and finally the uptake of vapors and paint particles reach equilibrium. Microporous carbons, in particular, were much more susceptible to paint particles. A Langmuir-type model for the uptake on activated carbons was suggested, which successfully described the adsorption behaviors of the off-gas released from vehicle spray painting booth. 相似文献
The electrochemical oxidation (EO) of environmentally persistent perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) with a Magnéli phase Ti4O7 electrode was investigated in this study. After 3 hours (hr) of electrolysis, 96.0 percent of PFOA (10 milligrams per liter [mg/L] in 100 milliliters [mL] 100 millimolar [mM] Na2SO4 solution) was removed following pseudo first‐order kinetics (k = 0.0226 per minute [min]) with the degradation half‐life of 30.7 min. Under the same treatment conditions, PFOS (10 mg/L in 100 mL 100 mM Na2SO4 solution) removal reached 98.9 percent with a pseudo first‐order degradation rate constant of 0.0491/min and the half‐life of 14.1 min. Although, the degradation of PFOA was slower than PFOS, when subjected to EO treatment in separate solutions, PFOA appeared to degrade faster than PFOS when both are present in the same solution, indicating possible competition between PFOA and PFOS during Ti4O7 anode‐based EO treatment with PFOA having the competitive advantage. Moreover, the EO treatment was applied to degrade highly concentrated PFOA (100.5 mg/L) and PFOS (68.6 mg/L) in ion‐exchange resin regenerant (still bottom) with high organic carbon content (15,800 mg/L). After 17‐hr electrolysis, the total removal of PFOA and PFOS was 77.2 and 96.5 percent, respectively, and the fluoride concentration increased from 0.84 mg/L to 836 mg/L. Also, the dark brown color of the original solution gradually faded during EO treatment. In another test using still bottom samples with lower total organic carbon (9,880 mg/L), the PFOA (15.5 mg/L) and PFOS (25.5 mg/L) concentrations were reduced to levels below the limits of quantification after 16‐hr treatment. In addition, the performance of EO treatment using different batch reactor setups was compared in this study, including one‐sided (one anode:one cathode) and two‐sided (one anode:two cathodes) setups. The two‐sided reactor configuration significantly enhanced the degradation efficiency, likely due to the larger anode area available for reactions. 相似文献
The main purpose of this study was to monitor ambient air particulates and particulate-bound Hg (Hg[p]) compositions in different crops in the coastal zone in the Taichung, Taiwan, area at a sampling site during 2013 October to 2013 December. In addition, a direct mercury analyzer (DMA-80) was used to directly detect the concentration with measured results by the regression equation of Hg in the ambient air. The results indicated that: 1) the mean values of ambient air Hg(p) compositions in rice displayed no significant differences for weeks one, two, and three versus those of the other crops (white cabbage, Arden lettuce, and Gynura procumbens); 2) for white cabbage, the higher the humidity, the lower the average ambient air Hg(p) compositions that were obtained, a phenomenon that was also reflected on the crops of white cabbage and G. procumbens; 3) Arden lettuce displayed no significant differences in the leaf Hg(p) compositions during weeks one, two, and three; however, the stem portions displayed significant differences in Hg(p) compositions during weeks two and three; and 4) the Spearman statistical method showed the mean differences for ambient air Hg(p) at the Long-jing sampling site (coastal regions) with four different crops (rice, white cabbage, Arden lettuce, and Gynura) in central Taiwan. The results further revealed no significant differences in mean values. 相似文献
This study investigates biogeochemical reductive release of arsenate from beudantite into solution in a crater area in northern Taiwan,using a combination of X-ray absorption near-edge structure (XANES) and atomic absorption spectrometry.Total arsenic (As) concentrations in the soil were more than 200 mg/kg.Over four months of laboratory experiments,less than 0.8% As was released into solution after reduction experiments.The 71% to 83% As was chemically reduced into arsenite (As(III)) and partially weathering into the soluble phase.The kinetic dissolution and re-precipitation of As,Fe,Pb and sulfate in this area of paddy soils merits further study. 相似文献