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Chemical Methods
Published in Somenath Mitra, Pradyot Patnaik, Barbara B. Kebbekus, Environmental Chemical Analysis, 2018
Somenath Mitra, Pradyot Patnaik, Barbara B. Kebbekus
The term chemical method refers to the qualitative and quantitative determination of pollutants at trace concentrations in environmental matrices by their chemical reactions by selectively carrying out such reactions. An appropriate reagent is therefore added to the sample or its extract to identify the product of specific reaction to determine the pollutant of interest. The chemical reaction employed for this purpose should therefore be singular to that particular substance, or to similar ions or compounds. Such reactions however may be subject to interference from the presence of other substances that may undergo similar reactions. Also it should be noted that the chemical methods are not restricted only to the identification and quantification of analytes but in many cases applied to their separation from interfering substances as well. Such reactions may be broadly subdivided into four types: (1) precipitation, (2) complexation/chelation, (3) oxidation/reduction, and (4) derivatization. These reactions are briefly discussed below. The analytical techniques used to measure the products of such reactions in environmental analyses may include wet methods such as, titrimetry or gravimetry or the instrumental methods, such as spectrophotometry, gas chromatography, high-performance liquid chromatography, or mass spectrometry. In titrimetry the end point of the titration is measured precisely by the change in color resulting from the reaction of the analyte with a suitable color-forming indicator. Such reactions are mostly but not always complexation/chelation type.
A review on performance, economic, and environmental analyses of integrated solid oxide fuel cell and biomass gasification systems
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2022
Anil Erdogan, Beyza Dursun, C. Ozgur Colpan, Azize Ayol
Environmental analysis of an integrated SOFC and biomass gasification system is done to evaluate the environmental impact mainly for the following problems: deforestation, land degradation, water pollution, air pollution, and climate change (Sansaniwal, Rosen, and Tyagi 2017). Two main techniques, which are exergo-environmental analysis and life cycle assessment, are used for this purpose. The CO2 emission value formulas used in the exergo-environmental analysis method are given im Eqs. (9) and (10) for the SOFC and CHP system, respectively. Approaches that combine the concepts of exergy and environmental assessment can be given as cumulative exergy consumption, exergoecological analysis, extended exergy accounting, and environomic method. However, these approaches do not include the life cycle of the components. In the life cycle assessment, emission values and consumption for each material stream during all processes within the life cycle are analyzed (Meyer et al. 2009).