Acetic Acid: Water Pollution And Its Effects

Acetic acid, also known as ethanoic acid, is a colourless liquid with a pungent vinegar-like odour. It is the main component of vinegar, which contains 4-18% acetic acid. Acetic acid is used in various household and industrial applications, including food processing, pharmaceuticals, and cleaning products. While it has several beneficial uses, acetic acid can also be a source of water pollution. Acetic acid can enter the environment through industrial discharge and emissions, as well as the burning of plastics, rubber, and vehicle exhaust fumes. In high concentrations, acetic acid can be corrosive to metals and harmful to human health. However, according to the Ecological Risk Classification of Organic Substances Approach, acetic acid is considered to have a low ecological hazard potential.

Acetic acid is corrosive to metals

Acetic acid is a colourless liquid with a pungent, vinegar-like odour. It is the second simplest carboxylic acid and is an important chemical reagent and industrial chemical. Acetic acid is corrosive to metals, including iron, magnesium, and zinc. When acetic acid comes into contact with these metals, it can cause the formation of hydrogen gas and salts known as acetates. For example, when acetic acid reacts with magnesium, it produces hydrogen gas and magnesium acetate:

> Mg + 2 CH3COOH → (CH3COO)2Mg + H2

Acetic acid can also react with other metals, such as aluminium, to form a passivating acid-resistant film of aluminium oxide. This property makes aluminium useful for transporting acetic acid, as it can be stored in aluminium tanks or containers lined with aluminium, glass, stainless steel, or polyethylene.

The corrosiveness of acetic acid on metals has been studied extensively, particularly in the context of its impact on steel pipelines in the oil and gas industry. The presence of acetic acid has been found to increase the corrosion rates of mild steel and carbon steel. The specific effects of acetic acid on the corrosion process are influenced by various factors, including temperature, concentration, and the presence of other substances such as carbon dioxide (CO2) and hydrogen sulfide (H2S).

In summary, acetic acid is a corrosive substance that can damage metals such as iron, magnesium, and zinc. Its corrosiveness has significant implications for industries that utilise metal pipelines or containers, particularly in the presence of other substances that can enhance its effects.

Acetic acid can cause skin and eye damage

Acetic acid is a colourless liquid with a pungent odour similar to vinegar. It is the main component of vinegar, which contains 4 to 18% acetic acid. Acetic acid is corrosive to the skin and eyes and can cause severe injury or even death. It is important to avoid skin and eye contact with acetic acid and to take the necessary precautions when handling this substance.

When acetic acid comes into contact with the skin, it can cause pain, burns, and ulcers. If left untreated, these burns can result in permanent scarring. In the case of eye contact, acetic acid can lead to pain, twitching eyelids, watery eyes, inflammation, sensitivity to light, and burns. These symptoms can be early signs of a chemical eye burn, which can have serious and long-term effects on vision if not treated promptly and adequately.

The severity of an acetic acid burn depends on the concentration of the substance, the duration of exposure, and the treatment provided. For example, exposure to dilute solutions of acetic acid (less than 25%) may cause irritation, while more concentrated solutions can result in corrosive damage. Similarly, inhalation of acetic acid vapours at low concentrations may irritate the eyes, nose, and throat, while higher concentrations can cause more severe symptoms such as chest tightness, headache, fever, and even eye damage.

To prevent and minimise the harmful effects of acetic acid on the skin and eyes, it is crucial to follow safety guidelines and use appropriate personal protective equipment. In the event of exposure, immediate irrigation of the affected area with lukewarm water for at least 10 to 15 minutes is recommended, followed by seeking medical advice. For eye exposure, removing contact lenses and irrigating the eyes with lukewarm water is crucial.

Acetic acid is used in food processing

Acetic acid is a colourless liquid with a pungent odour similar to vinegar. It is used in food processing in a variety of ways.

Firstly, acetic acid is used as a raw material and solvent in the production of other chemical products. It is also used in oil and gas production, as well as in the pharmaceutical industry. In food processing plants, it is commonly used as a cleaning and disinfecting product.

Secondly, acetic acid is used as a food preservative and food additive (known as E260). It is often used as a condiment, flavouring, and preservative in the pickling process. It is also a common ingredient in many processed food products, such as mayonnaise.

Thirdly, acetic acid is used in the production of synthetic fibres and fabrics. It is also used to make many chemicals, including vinyl acetate, acetic anhydride, and acetate esters.

Finally, acetic acid has medicinal properties and can be used to treat bacterial and fungal infections due to its antiseptic qualities. It is also used as a screening agent for cervical cancer and in chromoendoscopy for detecting the early stages of gastric cancers.

Acetic acid is a by-product of fermentation

Acetic acid, also known as ethanoic acid, is a colourless liquid with a pungent, vinegar-like odour. It is the second simplest carboxylic acid and is an important chemical reagent and industrial chemical. It is used in the production of cellulose acetate for photographic film, polyvinyl acetate for wood glue, and synthetic fibres and fabrics.

Acetic acid bacteria (AAB) are a group of Gram-negative bacteria that oxidise sugars or ethanol and produce acetic acid during fermentation. AAB are rod-shaped and obligate aerobes. They are actively present in environments where ethanol is formed as a product of the fermentation of sugars. They are commonly found in substrates containing sugar and/or ethanol, such as fruit juices, wine, cider, beer, and vinegar.

The oxidation of ethanol to acetic acid requires a massive amount of oxygen. To convert ethanol to acetic acid, oxidation steps take place, which involve converting ethanol to acetaldehyde and then to acetic acid. The ethanol produced earlier undergoes conversion to form acetaldehyde in the first step, which takes place when NAD and NADP are present. The second step consists of converting acetaldehyde to form acetic acid.

The commercial production of acetic acid can be done through two methods: the surface fermentation process and the submerged fermentation process. The surface fermentation process uses generators, such as trickling generators, which have a lining of birch wood shavings on their innermost surface. The ethanol passes through the generator from the top and trickles through the wood shavings, which contain essential bacteria. The solution reaches the bottom basin, cools down, and is pumped again. The process repeats until about 80-90% of ethanol conversion occurs.

The submerged fermentation process is more beneficial as it produces a higher amount of ethanol and requires a lower manual input. In this method, a higher concentration of acetic acid (13%) is obtained. The process takes place in a steel fermentor with a stirring mechanism at the bottom and a suction rotor for aeration. The air enters the fermentor from the top through a pipe, and a heat exchanger controls the temperature. The starting material should contain ethanol and acetic acid, with a concentration of ethanol of 5%. The process of fermentation in this method takes about 35 hours, and the temperature should be maintained at forty degrees Celsius. Around 98% acetic acid is formed from this method.

The product of the fermentation of acetic acid is vinegar, which has various applications in cooking, cleaning, and removing moulds. The intermediate product of fermentation is acetaldehyde.

Acetic acid can be used to treat contaminated water

Acetic acid is an acidic, colourless liquid and organic compound with the chemical formula CH3COOH. It is the second simplest carboxylic acid and is an important chemical reagent and industrial chemical. It is naturally produced by acetic acid bacteria, notably the genus Acetobacter and Clostridium acetobutylicum, and is present in some unprocessed foods, including fruit. Acetic acid is also a component of the vaginal lubrication of humans and other primates, where it serves as a mild antibacterial agent.

Acetic acid has a variety of applications, including as a food preservative and food additive (known as E260), in household cleaning products to remove limescale, and in the production of ink for textile printing, dyes, photographic chemicals, pesticides, pharmaceuticals, rubber and plastics.

Acetic acid has been shown to be effective in treating contaminated water. A study conducted in the Grand Bay National Estuarine Research Reserve (GBNERR) in Mississippi found that acetic acid treatment had a significant impact on the remediation of post-contamination and the survival of pathogens from the GBNERR Bayous Heron, Cumbest, and Pine-O-Pine. The study concluded that the interaction of physicochemical and microbiological parameters of water through external chemical manipulation by acetic acid may provide utility in the remediation of post-contamination with anthropogenic pathogens such as E. coli, Enterococci, Campylobacter, Vibrio, Giardia, and Cryptosporidium.

Another study, published in the *Biomedical Sciences Instrument*, also demonstrated the effectiveness of acetic acid in treating contaminated water. The research aimed to establish an effective and inexpensive methodology to remediate against anthropogenic seafood contamination. The study involved treating water samples from the GBNERR with different levels of acetic acid. The findings showed the total inactivation of eight pathogenic microbial species that constitute a public health threat to fishing activities at the GBNERR.

Acetic acid has also been used in cancer treatment since the 1800s, with acetic acid injections used to treat tumours. Additionally, it is used as an antiseptic and is on the World Health Organization's List of Essential Medicines for the treatment of otitis externa.

While acetic acid has a wide range of applications and can be used to treat contaminated water, it is important to note that it is a corrosive substance and can cause skin and eye irritation, as well as respiratory issues if inhaled. Therefore, it should be handled with caution and in accordance with safety guidelines.

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