Related Experiment Video
Updated: Jul 14, 2026
11:14
Two-way Valorization of Blast Furnace Slag: Synthesis of Precipitated Calcium Carbonate and Zeolitic Heavy Metal Adsorbent
Published on: February 21, 2017
Effects of calcium-based sorbents on PCDD/F formation from pentachlorophenol combustion process
1State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, 310027 Zhejiang, PR China.
Journal of Hazardous Materials
|June 19, 2007
Summary
Calcium-based sorbents impact dioxin formation from pentachlorophenol (PCP) combustion. While CaO promotes PCDD/F production, CaCO3 significantly inhibits it by up to 70%.
Area of Science:
- Environmental Chemistry
- Combustion Science
- Pollutant Formation
Background:
- Calcium-based sorbents are used to reduce acidic gas emissions from combustion.
- These sorbents can also influence the formation and emission of trace organic pollutants.
- Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) are toxic byproducts of combustion.
Purpose of the Study:
- To investigate the effect of calcium-based sorbents on the formation of PCDD/Fs from pentachlorophenol (PCP) during high-temperature combustion.
- To compare the efficacy of different calcium-based sorbents (CaO, CaCO3, basic fly ash) in controlling PCDD/F emissions.
Main Methods:
- Batch experiments were conducted to study the high-temperature thermo-decomposition of PCP in the presence of calcium-based sorbents.
- Analysis of PCDD/F homologue distribution and total emission levels (I-TEQ).
- Characterization of reaction residue micro-surface structures.
Main Results:
- Highly chlorinated PCDD/F homologues were the primary dioxin products from PCP decomposition.
- CaO addition promoted the production of PCDDs and 4-7DFs, with a significant increase observed when the Ca/Cl ratio rose from 1 to 2.
- CaCO3 demonstrated strong inhibition of PCDD/F formation, achieving up to 70% inhibition efficiency, while CaO and fly ash showed promotion effects.
Conclusions:
- The type of calcium-based sorbent significantly influences PCDD/F formation from PCP combustion.
- CaCO3 is effective in inhibiting PCDD/F formation, suggesting its potential for emission control.
- Proposed mechanisms involve condensation, dechlorination, and acid-base interactions, explaining the differing effects of CaO and CaCO3.
Related Concept Videos
04:01Factors Affecting Solubility
Compared with pure water, the solubility of an ionic compound is less in aqueous solutions containing a common ion (one also produced by dissolution of the ionic compound). This is an example of a phenomenon known as the common ion effect, which is a consequence of the law of mass action that may be explained using Le Chȃtelier’s principle. Consider the dissolution of silver iodide:
01:19Gas Chromatography: Types of Detectors-II
In gas chromatography, different detectors are employed to meet specific analytical needs. These detectors are often categorized based on their detection mechanisms and the types of compounds they are best suited to analyze. Thermal Conductivity Detectors (TCD), Flame Ionization Detectors (FID), and Electron Capture Detectors (ECD) represent common categories, each with unique operating principles and applications. However, beyond these, several other detectors are designed for more specialized...
03:46Qualitative Analysis
For solutions containing mixtures of different cations, the identity of each cation can be determined by qualitative analysis. This technique involves a series of selective precipitations with different chemical reagents, each reaction producing a characteristic precipitate for a specific group of cations. Metal ions within a group are further separated by varying the pH, heating the mixture to redissolve a precipitate, or adding other reagents to form complex ions.
For instance, group IV...
For instance, group IV...
00:52Washing, Drying, and Ignition of Precipitates
After filtration, the precipitate is washed to remove coprecipitated impurities and any remaining mother liquor. Colloidal precipitates, such as silver chloride, are washed with an electrolyte (such as dilute nitric acid) to prevent the peptization of the precipitate. In the case of slightly soluble precipitates, the wash solution contains a common ion to reduce solubility. Lead sulfate, which is slightly soluble in water, is washed with dilute sulfuric acid. Similarly, wash solutions may be...
01:10Hydrolysis of Chlorobenzene to Phenol: Dow Process
Simple aryl halides do not react with nucleophiles under normal conditions. However, the reaction can proceed under drastic conditions involving high temperatures and high pressure to give the substituted products. For example, chlorobenzene is converted to phenol using aqueous sodium hydroxide at 350 °C under high pressure by the Dow process. The reaction follows an elimination-addition mechanism involving a benzyne intermediate. Here, the chloride ion is eliminated to generate the benzyne...