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951.
催化湿法氧化处理垃圾渗滤液中Co/Bi催化剂的回收与再生 总被引:3,自引:0,他引:3
利用硝酸盐熔融法制备Co/Bi催化剂,用于催化湿法氧化(CWAO)处理垃圾渗滤液。对一次利用后的 Co/Bi催化剂进行回收和再生,在反应温度260 ℃、催化剂用量 2 g、氧分压 0. 5 MPa条件下,催化剂的回收率可达到(97. 09±0. 74)%。利用XRD、BET分析方法对新鲜制备、一次回收、一次再生、二次回收的催化剂进行表征,根据表征结果可知催化剂的活性为:新鲜制备>一次再生>二次回收>一次回收。利用上述催化剂在不同温度条件下降解垃圾渗滤液,在 280 ℃、300 ℃条件下,催化剂的活性为新鲜制备≈一次再生>一次回收,而在220 ℃、240 ℃、260 ℃条件下,则是新鲜制备>一次再生≈一次回收,表明低温条件下,一次再生的催化剂和一次回收的催化剂出现失活现象,并分析了催化剂失活的原因。 相似文献
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954.
Biofiltration pretreatment for reverse osmosis (RO) membrane in a water reclamation system 总被引:2,自引:0,他引:2
Biofouling control is considered as a major challenge in operating membrane systems. A lab-scale RO system was setup at a local water reclamation plant to study the feasibility of using biofiltration as a pretreatment process to control the biofouling. The biological activity in the RO system (feed, product, reject streams) was tested using the standard serial dilution plating technique. Operational parameters such as differential pressure (DP) and permeate flowrate of the system were also monitored. Effects of biofilter on AOC and DOC removals were investigated. Biofiltration was found to be a viable way of assimilable organic carbon (AOC) and dissolved organic carbon (DOC) removals, with removal efficiencies of 40-49% and 35-45% at an empty bed contact time (EBCT) of 30 min. It was also found that using the biofiltration as a pretreatment reduced the rate of biofouling. It took only about 72 h for biofouling to have a significant impact on the performance of the RO membrane, when the system was operated without using biofiltration as pretreatment. There was, however, a five times increase in operational length to more than 300 h when biofiltration was used. This study presented the suitability of the biofilter as an economical and simple way of biofouling control for RO membrane. 相似文献
955.
The response of cyanide metabolism rates of two woody plants to changes in temperature is investigated. Detached leaves (1.0 g fresh weight) from weeping willow (Salix babylonica L.) and Chinese elder (Sambucus chinensis Lindl.) were kept in glass vessels with 100ml of aqueous solution spiked with potassium cyanide for a maximum of 28 h. Ten different temperatures were used ranging from 11 degrees C to 32 degrees C. The disappearance of aqueous cyanide was analyzed spectrophotometrically. The cyanide removal rate of Chinese elder was higher than that of weeping willow at all temperatures. The highest cyanide removal rate for Chinese elder was found at 30 degrees C with a value of 12.6 mg CN kg(-1) h(-1), whereas the highest value of the weeping willow was 9.72 mg CN kg(-1) h(-1) at 32 degrees C. The temperature coefficient values, Q10, which are the ratio of removal rates at a 10 degree difference, were determined for Chinese elder and weeping willow to 1.84 and 2.09, respectively, indicating that the cyanide removal rate of weeping willow was much more susceptible to changes in temperature than that of the Chinese elder. In conclusion, changes in temperature have a substantial influence on the removal rate of cyanide by plants. 相似文献
956.
Martuzevicius D Grinshpun SA Reponen T Górny RL Shukla R Lockey J Hu S McDonald R Biswas P Kliucininkas L Lemasters G 《Atmospheric environment (Oxford, England : 1994)》2004,38(8):1091-1105
The PM(2.5) concentration and its elemental composition were measured in the Cincinnati metropolitan area, which is characterized by intense highway traffic. The spatial and temporal variations were investigated for various chemical elements that contributed to the PM(2.5) fraction during a 1-year-long measurement campaign (December 2001-November 2002). The ambient aerosol monitoring was performed in 11 locations around the city during nine measurement cycles. During each cycle, four Harvard-type impactors were operating in parallel in specific locations to explore various factors affecting the PM(2.5) elemental concentrations. The sampling was performed during business days, thus assuring traffic uniformity. The 24-h PM(2.5) samples were collected on Teflon and quartz filters. Teflon filters were analyzed by X-ray fluorescence (XRF) analysis while quartz filters were analyzed by thermal-optical transmittance (TOT) analysis. In addition to PM(2.5) measurements, particle size-selective sampling was performed in two cycles using micro-orifice uniform deposit impactor; the collected fractionated deposits were analyzed by XRF. It was found that PM(2.5) concentration ranged from 6.70 to 48.3 mug m(-3) and had low spatial variation (median coefficient of variation, CV=11.3%). The elemental concentrations demonstrated high spatial variation, with the median CV ranged from 38.2% for Fe to 68.7% for Ni. For traffic-related trace metals, the highest concentration was detected in the city center site, which was close to a major highway. The particle size selective measurement revealed that mass concentration of the trace metals, such as Zn, Pb, Ni, as well as that of sulfur reach their peak values in the particle size range of 0.32-1.0 mum. Meteorological parameters and traffic intensity were not found to have a significant influence on the PM(2.5) elemental concentrations. 相似文献
957.
A microbial consortium consisting of a white-rot fungus 8-4* and a Pseudomonas 1-10 was isolated from wastewater treatment facilities of a local dyeing house by enrichment, using azo dye Direct Fast Scarlet 4BS as the sole source of carbon and energy, which had a high capacity for rapid decolorization of 4BS. To elucidate the decolorization mechanisms, decolorization of 4BS was compared between individual strains and the microbial consortium under different treatment processes. The microbial consortium showed a significant improvement on dye decolorization rates under either static or shaking culture, which might be attributed to the synergetic reaction of single strains. From the curve of COD values and the UV-visible spectra of 4BS solutions before and after decolorization cultivation with the microbial consortium, it was found that 4BS could be mineralized completely, and the results had been used for presuming the degrading pathway of 4BS. This study also examined the kinetics of 4BS decolorization by immobilized microbial consortium. The results demonstrated that the optimal decolorization activity was observed in pH range between four and 9, temperature range between 20 and 40 degrees C and the maximal specific decolorization rate occurred at 1,000 mg l(-1) of 4BS. The proliferation and distribution of microbial consortium were also microscopically observed, which further confirmed the decolorization mechanisms of 4BS. 相似文献
958.
调理剂对CAF污泥浓缩工艺影响的试验研究 总被引:1,自引:0,他引:1
涡凹气浮(CAF)已广泛应用于工业废水和城市污水的预处理中.由于污泥本身的特性原因,CAF在污泥处理中尚没有应用.通过试验投加污泥调理剂改变污泥的特性,以达到将CAF工艺用于浓缩活性污泥的目的.试验表明,CAF工艺浓缩低浓度剩余活性污泥效果很好,但正确选择污泥调理剂的投加点和投加量对CAF污泥浓缩工艺至关重要. 相似文献
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