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Biological samples are extracted with n-hexane/acetone (60:40) and 1 mL of the concentrated extract is eluted through a pasteur pipette column prepacked with alumina (0.3 g) and silicic acid (0.25 g) with 10 mL n-hexane (containing 4% acetone). The fat and other co-extractives are retained by the column and clear eluate is directly injected on a GLC column for determination on electron capture detector. A comparison of the Pasteur pipette cleanup with the modified method of Cole et al. (1967) on 41 samples of fish, One Step Method, (Ahmad and Marolt (1986] on 86 samples of fish and Maunder et al. (1964) on 10 type of wildlife (100 samples) was made. The Pasteur pipette method gives results which are significantly higher (p greater than 0.5) than the other methods except the One step method. The Pasteur pipette method has a detection limit of 0.01 microgram/g for DDT and its metabolites. 相似文献
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Used lubricating oil recycling using hydrocarbon solvents 总被引:1,自引:0,他引:1
A solvent extraction process using new hydrocarbon solvents was employed to treat used lubricant oil. The solvents used were liquefied petroleum gas (LPG) condensate and stabilized condensate. A demulsifier was used to enhance the treatment process. The extraction process using stabilized condensate demonstrated characteristics that make it competitive with existing used oil treatment technologies. The process is able to reduce the asphaltene content of the treated lubricating oil to 0.106% (w/w), the ash content to 0.108%, and the carbon residue to 0.315% with very low levels of contaminant metals. The overall yield of oil is 79%. The treated used oil can be recycled as base lubricating oil. The major disadvantage of this work is the high temperature of solvent recovery. Experimental work and results are presented in detail. 相似文献
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Zaheer Aslam Ibnelwaleed A. Hussein Mohammad Anwar Parvez Waqar Ahmad Ihsanullah 《Journal of the Air & Waste Management Association (1995)》2019,69(2):246-257
Waste oil fly ash (OFA) collected from disposal of power generation plants was treated by physicochemical activation technique to improve the surface properties of OFA. This synthesized material was further used for potential hydrogen sulfide (H2S) adsorption from synthetic natural gas. The raw OFA was basically modified with a mixture of acids (20% nitric acid [HNO3] and 80% phosphoric acid [H3PO4]), and it was further treated with 2 M potassium hydroxide (KOH) to enhance the surface affinity as well as surface area of synthesized activated carbon. Correspondingly, it enhanced the adsorption of H2S. Crystallinity, surface morphology, and pore volume distribution of prepared activated carbon were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET) analyses. Fourier transform infrared (FTIR) study was also performed to identify the functional groups during different synthesis stages of modified activated carbon. The Langmuir, Freundlich, Sips, and dual-site Langmuir (DSL) models were used to study the kinetic and breakthrough behavior of H2S adsorption over alkali-modified activated carbon. Modeling results of isotherms indicated that OFA has dual sites with high and low affinity for H2S adsorption. The Clark model, Thomas model, and Yoon-Nelson model were used to examine the effects of flow rate and inlet concentration on the adsorption of H2S. Maximum uptake capacity of 8.5 mg/g was achieved at 100 ppm inlet concentration and flow rate of 0.2 L/min.
Implications: Utilization of worthless oil fly ash from power plant is important not only for cleaning the environment but also for solid waste minimization. This research scope is to eradicate one pollutant by using another pollutant (waste ash) as a raw material. Chemical functionalization of synthesized activated carbon from oil fly ash would lead to attachment of functional groups of basic nature to attract the acidic H2S. Such type of treatment can enhance the uptake capacity of sorbent several times. 相似文献
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