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Jianyin Xiong Wenhao Chen James F. Smith Yinping Zhang Jianshun Zhang 《Atmospheric environment (Oxford, England : 1994)》2009,43(26):4102-4107
Based on the extraction method presented by Smith et al. (2008), this paper proposes an improved method, the multi-emission/flush regression method, to simultaneously determine the initial emittable concentration and the partition coefficient. Compared to the extraction method, the proposed method has the following advantages: (1) it is unnecessary for the target volatile organic compounds (VOCs) to emit completely from the material, thus greatly reducing experimental time; (2) it provides a simpler way to obtain the partition coefficients of VOCs for tested materials and can avoid the measurement uncertainties at low VOC concentrations which often occur during the last few cycles of the extraction method; (3) it does not require grinding the building material into powders thus making this method more convenient to use. Comparisons were made between the initial emittable VOC concentrations determined by the original extraction method and the proposed method. Results show good agreements between these two methods. To further validate the proposed method, the type of static chamber developed by Wang et al. (2006) was used to conduct the experiment for a type of medium density board, and formaldehyde was selected as the target compound. Based on the initial emittable concentration and partition coefficient obtained using the proposed method, and the diffusion coefficient obtained by the mercury intruding porosimetry, the chamber formaldehyde concentration was predicted and compared with the experimental measurements. Results show that the predicted chamber VOC concentration using the measured parameters agree well with the experimental data. 相似文献
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絮凝剂的开发及其应用进展 总被引:2,自引:1,他引:2
文章对无机絮凝剂、有机高分子絮凝剂、微生物絮凝剂(MBF)和其他絮凝剂进行了介绍,综述了絮凝剂的研究现状,对以上几种絮凝剂在废水处理等领域中的应用情况进行了阐述。比较了几种絮凝剂的特点,并对絮凝剂的发展趋势进行分析和展望。 相似文献
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Fangzhou Li Jiangshan Zhou Chun Du Wei Li Yinzhen Wang Guannan He Qinyu He 《环境科学学报(英文版)》2017,29(10):24-32
A one-step microwave irradiation method was used to deposit carbon and nitrogen co-doped TiO_2((C, N)-TiO_2) on commercial brick((C, N)-TiO_2/brick). The as-prepared samples were characterized by X-ray diffraction, ultraviolet–visible(UV–vis) diffuse reflectance spectroscopy, photoluminescence spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy(SEM). A selective technique was also used to investigate the concentration of hydroxyl radicals during UV–vis irradiation of the Methyl Orange solution with the as-prepared samples. The C and N dopants enhanced visible light absorption and provided a longer lifetime for the photo-generated electron–hole pairs. The SEM images showed that the as-prepared sample is porous. The dark adsorption and photodegradation test for(C, N)-TiO_2/brick showed good photodegradation and good recyclability. The best photodegradation rate was 94% after 2 hr. The maximum degradation rate was maintained even after the 6th cycle. The good photocatalytic properties are attributed to the enhanced visible light absorption, enhanced pollutant adsorption arising from the porous structure of the(C, N)-TiO_2 thin film, and longer lifetime of the photo-generated electron–hole pairs.(C, N)-TiO_2/brick should have potential commercial applications in photodegradation processes because of its low cost, good photodegradation, and excellent recyclability. 相似文献
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Zhimou Wei Ya Xiong Jian Chen Jing Bai Jing Wu Jiane Zuo Kaijun Wang 《环境科学学报(英文版)》2018,30(7):183-191
The feasibility of copper recovery by induced crystallization in a long period(174 days) was investigated in a seeded fluidized bed reactor(FBR). The process was divided into 3 periods according to different influent conditions, and the period III was separated into III-a and IIIb due to the adjustment of the molar ratio of CO_3~(2-)concentration to copper concentration([CT]/[Cu~(2+)]). The removal efficiency could exceed 95% and the average effluent copper concentration decreased to 3.0 mg/L. The mean particle size of seed grains with copper crystals coating on, raised to 0.36 mm from initial 0.18 mm. During period III-a, the supersaturation exceeded 2.88 × 104, the removal efficiency decreased to 60%–80% and the particle size dropped to 0.30 mm, due to the generation of fines by homogeneous crystallization and seeds breaking. And the morphology of the crystals on the seed grains changed from rod-like to spherical which lead to the particle size decreasing. In period III-b,the supersaturation was modified by adjusting the molar ratio of [CT]/[Cu2+] to 1.2 from 2.The efficiency was back to 95% and the mean particle size grew to 0.36 mm at the end of IIIb, the crystals coating on the seeds turned back to rod-like products of good stability. This study illustrated that the copper salt crystal could keep on growing on the seed grains for over 150 days, the feasibility and controllability of copper recovery by induced crystallization process in FBR were satisfactory, even under the dramatic changes in influent conditions. 相似文献