Table of Contents
How does reductive dechlorination work?
Cometabolic Anaerobic Reductive Dechlorination is a process where chlorinated compounds are reduced by non-specific enzymes or co-factors that are generated for metabolism by another compound (i.e., the primary substrate) in an anaerobic environment.
What is meant by reductive dehalogenation?
The process of removing a halogen from a halogenated organic compound by a reductive reaction is referred to as reductive dehalogenation. Reductive reactions are ones in which electrons are transferred to the carbon-halogen bond, thereby lowering the oxidation state of the parent compound (example reactions below).
What is aerobic dechlorination?
10.3. Under anaerobic conditions, dechlorination is the removal of one or more chlorine substitutions on the PCB molecule (dechlorination is a minor factor in systems that are mostly aerobic).
Does sodium bisulfite remove chlorine?
Sodium Bisulfite Sodium bisulfite reduces free chlorine to sodium bisulfate and hydrochloric acid. The chloramines are converted to sodium bisulfate, hydrochloric acid, and ammonium chloride. The theoretical dosage for dechlorination requires 1.78 parts of pure sodium sulfite per part chlorine or chloramines.
What is the meaning of dehalogenation?
In organic chemistry dehalogenation is a set of chemical reactions that involve the cleavage of C-halogen bonds. Dehalogenations come in many varieties, including defluorinaion, dechlorination, debromination, and deiodination. Incentives to investigate dehalogenations include both constructive and destructive goals.
What is anaerobic bioremediation?
Anaerobic bioremediation of chlorinated solvents, a process also known as reductive dechlorination, is the biologically mediated process by which chlorinated hydrocarbons are degraded under anoxic or anaerobic conditions.
What are the advantages of Anaerobic bioremediation?
The EPA explains that bioremediation uses either aerobic or anaerobic micro-organisms to reduce environmental impacts to air, water, and soil. The micro-organisms accomplish this by degrading the chemicals of concern into non-toxic substances over time, using them as an energy source in the process.
What is the use of SMBS in RO plant?
Sodium metabisulphite (SMBS) is the current standard preservation chemical used in RO plants during shut down. It is a cheap and efficient preservative, but its tendency to oxidize easily has several drawbacks.
What is the purpose of sodium bisulfite?
Sodium Bisulfite is a white, crystalline solid with a slight odor of rotten eggs. It is often in a liquid solution. It is used in making paper and leather, as a food preservative and in dye and chemical production.
How does sodium metabisulfite remove chlorine?
Sodium Metabisulfite Sodium metabisulfite reduces free chlorine to form sodium bisulfate (NaHSO4) and hydrochloric acid (HCl). The Chloramines are converted to sodium bisulfate, hydrochloric acid, and ammonium chloride (NH4Cl).
What chemicals neutralize chlorine?
VITAMIN C
VITAMIN C DECHLORINATION Vitamin C is a newer chemical method for neutralizing chlorine. Two forms of vitamin C, ascorbic acid and sodium ascorbate, will neutralize chlorine. Neither is considered a hazardous chemical.
What is the difference between dehydrohalogenation and dehalogenation?
Hint:Dehydrogenation or dehydration describes the removal of hydrogen atoms whereas, dehalogenation describes the removal of halogens. Therefore, as the name suggests, dehydrohalogenation suggests the removal of hydrogen and a halogen group.
What is the difference between aerobic and anaerobic biodegradation?
From a microbial perspective, there are two methods for biodegradation: Aerobic in which organisms use oxygen as part of the respiration for consumption of nutrients. Anaerobic in which organisms use other elements such as sulfur, in the process of respiration and consumption of nutrients.
What is aerobic and anaerobic bioremediation?
When an organism requires oxygen to break down an environmental contaminant, we call that aerobic bioremediation. And, when an organism carrying out bioremediation can breathe some other molecule besides oxygen, we call that anaerobic bioremediation.
What is reductive dechlorination?
Reductive dechlorination Chlorinated solvents may undergo a different anaerobic biodegradation process, reductive dechlorination, in which the chlorine atoms are sequentially removed from the contaminant molecule and substituted by hydrogen as shown for PCE in Fig. 2.8and for carbon tetrachloride in Fig. 2.9. Figure 2.8.
How do dechlorinating bacteria work in soil?
The dechlorinating bacteria use this H 2 as their electron donor, ultimately replacing chlorine atoms in the chloroethenes with hydrogen atoms via hydrogenolytic reductive dechlorination. This process can proceed in the soil provided the availability of organic electron donors and the appropriate strains of Dehalococcoides.
What are the advantages of in-situ dechlorination?
One of the most common in-situ approaches is the use of bioremediation and reductive dechlorination. The advantages to using in situ bio-remediation or reductive dechlorination technology are that a liquid can be injected into the subsurface using a small drilling rig while there is minimal business interruption.
Why is Zn/AcOH used in dechlorination of ketene?
Reductive Dechlorination Reductive dechlorination of the products with Zn/AcOH allows access to cyclobutanones, which are the products of addition of ketene itself. From:Stereochemistry and Organic Reactions, 2021