A new, passive particle deposition air sampler, called the Einstein-Lioy Deposition Sampler (ELDS), has been developed to fill a gap in passive sampling for near-field particle emissions. The sampler can be configured in several ways: with a protective hood for outdoor sampling, without a protective hood, and as a dust plate. In addition, there is an XRF-ready option that allows for direct sampling onto a filter-mounted XRF cartridge which can be used in conjunction with all configurations. A wind tunnel was designed and constructed to test the performance of different sampler configurations using a test dust with a known particle size distribution. The sampler configurations were also tested versus each other to evaluate whether or not the protective hood would affect the collected particle size distribution. A field study was conducted to test the sampler under actual environmental conditions and to evaluate its ability to collect samples for chemical analysis. Individual experiments for each configuration demonstrated precision of the sampler. The field experiment demonstrated the ability of the sampler to both collect mass and allow for the measurement of an environmental contaminant i.e. Cr(6+). The ELDS was demonstrated to be statistically not different for Hooded and Non-Hooded models, compared to each other and the test dust; thus, it can be used indoors and outdoors in a variety of configurations to suit the user's needs. 相似文献
Cadmium (Cd) and lead (Pb) in water and soil could be adsorbed by biochar produced from corn straw. Biochar pyrolyzed under 400°C for 2 h could reach the ideal removal efficiencies (99.24%and 98.62% for Cd and Pb, respectively) from water with the biochar dosage of 20 g·L–1 and initial concentration of 20 mg·L–1. The pH value of 4–7 was the optimal range for adsorption reaction. The adsorption mechanism was discussed on the basis of a range of characterizations, including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and Raman analysis; it was concluded as surface complexation with active sorption sites (-OH, -COO-), coordination with π electrons (C = C, C = O) and precipitation with inorganic anions (OH-, CO32–, SO42–) for both Cd and Pb. The sorption isotherms fit Langmuir model better than Freundlich model, and the saturated sorption capacities for Cd and Pb were 38.91 mg·g-1 and 28.99 mg·g–1, respectively. When mixed with soil, biochar could effectively increase alkalinity and reduce bioavailability of heavy metals. Thus, biochar derived from corn straw would be a green material for both removal of heavy metals and amelioration of soil.
Given their voluminous application, significant amounts of fluoroquinolones are discharged into the environment through wastewater effluent. Adsorption has been shown to be a critical process controlling the environmental behaviors of fluoroquinolones. Competition between ofloxacin (OFL) and naphthalene (NAP)/bisphenol A (BPA) and their adsorption on activated carbon (AC), graphite (GP), and humic acid (HA) were investigated. The suppressed adsorption of OFL was observed on AC and GP, but not on HA, by NAP or BPA. Moreover, for AC, the competition by NAP was slightly stronger than that by BPA. However, for GP, the competition with BPA was higher than that with NAP. These observations indicate that competitive adsorption of OFL with respect to NAP/BPA depends on the degree of overlap of adsorption sites, as interpreted by the following: (i) AC can provide overlapping adsorption sites for OFL, BPA, and NAP, which include non-specific adsorption sites, such as hydrophobic sites, π-π interactions, and micropore filling; (ii) π-π interactions and hydrogen bonding might be responsible for the strong competitive adsorption between BPA and OFL on GP; and (iii) OFL adsorbs on HA through specific adsorption force—electrostatic attraction, with which NAP and BPA cannot compete.
Irradiation cross-linked polyethylene (PEX) and irradiation cross-linked polyethylene with carbon black filler (CB-PEX) are two types of scraps, generated in electric cable production. Their pyrolysis is studied in this work using instrumental TG\DSC\FTIR techniques and kinetic analysis. The experiments are performed at a constant heating rate of 10 °C/min in nitrogen flow at atmospheric pressure. It is found that the main pyrolysis stage is in the temperature range of 395–503 °C for PEX, and in range of 408–515 °C for CB-PEX. In the main pyrolysis stage, CB-PEX requires more external heat than PEX does. Olefins are the major products of pyrolysis for both materials, but they are quite different in their composition and molecular weight distribution. PEX can be converted almost quantitatively into volatile compounds. CB-PEX has a stronger coking tendency, as well as a larger residue composed of carbon black. 相似文献
Agricultural wastewater that produces color are of environmental and health concern as colored effluent can produce toxic and carcinogenic by-products. From this study, batch culture optimization using response surface methods indicated that the fungus isolated from the pineapple solid waste, Curvularia clavata was able to decolorize sterile palm oil mill effluent (POME) which is mainly associated with polyphenol and lignin. Results showed successful decolorization of POME up to 80 % (initial ADMI [American Dye Manufacturing Index] of 3,793) with 54 % contributed by biosorption and 46 % by biodegradation after 5 days of treatment. Analysis using HPLC and GC-MS showed the degradation of color causing compound such as 3-methoxyphenyl isothiocynate and the production of new metabolites. Ecotoxicity test indicated that the decolorized effluent is safe for discharge. To determine the longevity of the fungus for a prolonged decolorization period, sequential batch decolorization studies were carried out. The results showed that lignin peroxidase and laccase were the main ligninolytic enzymes involved in the degradation of color. Carboxymethyl cellulase (CMCase) and xylanase activities were also detected suggesting possible roles of the enzymes in promoting growth of the fungus which consequently contributed to improved decolorization of POME. In conclusion, the ability of C. clavata in treating color of POME indicated that C. clavata is of potential use for decolorization and degradation of agricultural wastewater containing polyphenolic compounds. 相似文献