Where is phenol found

Application of products containing a high concentration of phenol to the skin causes blisters and burns on the skin; heart, kidneys, and liver damage may occur with exposure to high levels of phenol [ 39 ]. Because of their tendency to readily oxidise to quinone radicals, which tend to be more reactive, catechols have the tendency to cause DNA damage or arylation, destroy some proteins in the body and disrupt transportation of electrons in energy transducing membranes [ 35 ].

Caffeic and dihydrocaffeic acids, in the presence of copper, also cause damage to DNA [ 40 ]. Chlorophenol poisoning causes mouth burning, throat burning and necrotic lesions in the mouth, stomach and oesophagus. It also induces abnormal temperature and pulse fluctuation, weak muscles and convulsions [ 41 ]. Other effects of chlorophenol poisoning include damage to the liver, kidneys, lungs, skin and the digestive tract [ 42 ].

Hydroquinone also damages chromosomes. Recovery of phenolic compounds from the aquatic environment is a mandatory requirement in order to safeguard the life of humans and aquatic organisms through possible contamination of these toxic chemicals. This section, therefore, discusses various techniques being employed to effectively eliminate phenolic compounds from wastewater prior to their final discharge into water bodies.

Photocatalytic degradation is the use of metal oxide catalysts to degrade pollutants where the catalyst is usually activated by absorption of a photon of appropriate energy and is capable of speeding up the reaction without being used up [ 44 ]. Photocatalytic properties of metal oxide catalysts are due to the fact that excitation of electrons from the valence to the conduction band of the catalyst occurs upon its irradiation with a light of appropriate wavelength.

These highly reactive radicals then attack and convert the pollutants to harmless products such as carbon dioxide and water [ 45 , 46 ]. Photocatalytic degradation is regarded as an efficient technique for the elimination of pollutants from polluted water as a result of its ability to completely degrade the pollutant instead of their transformation into other products.

The degree of effectiveness of the degradation process is known to rely heavily on the catalyst dose, exposure time, solution pH and light intensity [ 47 ]. There have been a number of reports where photocatalytic degradation techniques have been utilised effectively to degrade phenol and its derivative from the water.

The results confirmed that using zeolite as a support for FeO enhanced its photocatalytic degradation efficiency. In their study, Shahrezaei et al. Ozone O 3 is formed naturally when ultraviolet UV rays from the sun enter the earth's atmosphere. It is also formed whenever lightning strikes during a thunderstorm.

Ozone has a very high oxidising potential This high oxidation potential forms the basis of the use of ozone as an oxidant for removal of organic pollutants from water.

The wastewater is then allowed to flow along a venture throat, which generates a vacuum and pulls the ozone into the wastewater, or the ozone is simply bubbled up through the wastewater. The ozone then oxidises and decomposes the pollutants leading to their elimination from the water.

Some advantages of ozonation include [ 55 ]: The process is completely natural with no inclusion of chemicals and produces no chemical waste. High microorganism elimination efficiency with the microorganisms having no potential to developing resistance against ozone. Ability to remove organic, inorganic, microorganism and improve taste and odour of the water.

Based on the above advantages, several research works have been performed on the use of ozonation technique for phenolic compounds removal from wastewater.

Ozonation was also used to treat ethylene glycol containing wastewaters with emphasis on the impacts of pollutant dose, process time, and pH on the decontamination efficacy. After min, ethylene glycol removal efficiencies were Removal efficiency was observed to be highest in alkaline medium [ 57 ].

Among the techniques used for removal of phenolics from water is extraction using polar organic solvents. This technique separates compounds on the basis of their solubilities in two immiscible liquids. The compounds are normally separated from one liquid phase to another. The immiscible liquids usually consist of water and an organic solvent. The extraction efficiency was observed to vary according to the ratio of the solvent used.

The best solvent for phenol extraction was Aliquat Liu et al. Cumene showed excellent extraction performance on phenol in acidic solution. The distribution coefficient was observed to be directly proportional to the temperature but decreased with increasing pH value.

Solid phase extraction system consists of a syringe containing a merged silica fibre, which is coated with an immobilised phase. The aqueous solution containing the analyte is exposed to the fibre with the subsequent accumulation of the analyte on the stationary phase.

The fibre is then removed from the aqueous solution followed by desorption of the extracted analyte in a column injector or gas chromatography. Polydimethylsiloxane is normally used as the stationary phase for removal of halogenated and polycyclic aromatic hydrocarbons and polychlorinated biphenyls [ 60 ]. Effects of humic acid and surfactant concentrations on the extraction efficiency were analysed. They attributed the successful extraction of naphthols, alkylated phenols and Tetra-ols from the wastewater to the fact that the polyacrylate coating demonstrated high specificity for polar hydroxylated aromatic compounds.

Their study involved the use of iron oxide nanoparticles modified with activated carbon as the solid adsorbent. They demonstrated that development of solid phase extraction method based on magnetised activated carbon prior to their spectrophotometric determination is an appropriate technique. Biological method of phenolic compound removal from wastewater is subdivided into microbial and enzymatic methods.

The microbial method involves the deployment of bacteria, yeast and fungi in breaking down the phenolics into harmless products such as carbon dioxide and water. This method of phenolics removal is feasible as a result of the fact that some microorganisms are known to depend on aromatic compounds, including phenolics, as their source of carbon or nutrient [ 63 , 64 ]. It has the advantage of a comparatively low operational cost. Microbial removal of phenolic compounds occurs through either aerobic or anaerobic processes and begins with hydroxylation introduction of hydroxyl groups of the aromatic ring [ 65 ].

Hydroxylation through aerobic degradation involves two steps with catechol being the end product [ 66 ]: Reduction of one of the molecular oxygen to water under the influence of a hydrogen donor reduced pyrimidine nucleotide , and devouring of the other oxygen atom. The second step of the hydroxylation process occurs in the presence of dioxygenase enzyme with the subsequent formation of catechols.

Cleavage of the catechol aromatic rings then passes through various stages with specific enzymes, based on the type of microorganisms, resulting in the conversion of the phenolic compounds to compounds such as carbon dioxide and water [ 67 ].

Anaerobic degradation occurs whenever oxidising agents such as sulphates, nitrates and CO 2 , or light are present.

In general, the aerobic process is known to be better suited for the degradation of phenolics with minimal substituents consisting of halogens. On the other hand, the anaerobic process is mostly appropriate for reduction of chlorinated phenolic compounds [ 69 ].

The anaerobic system produces methane in addition to carbon dioxide and water. A major advantage of the anaerobic system of degradation is the absence of aeration cost, recovery of methane and minimum excess biomass generation [ 70 ]. Kukadiya et al.

In their experiment, Sinha et al. RSP8 bacteria strain. The two pollutants, however, repressed each other's degradation by the cells in the mixed substrate experiment. The enzymatic method of degradation, however, employs enzymes biological catalysts. Enzymes can be used effectively to selectively eliminate pollutants in water since they catalyse specific reactions under modest temperature, pH and ionic strengths [ 73 ]. In addition, the enzymatic reaction is known to occur at much faster rates compared to other types of reactions [ 74 ].

As an advantage over the microbial system of pollutant degradation, the enzymatic system of pollutant removal can occur under conditions, which are unfavourable or toxic to bacteria. This system can operate under different pollutant concentration high or low , eliminates the time requirement for biomass acclimatisation, involves no shock loading effect and with no generated biomass [ 74 ]. This method receives a high level of consideration due to its high pollutant removal efficiency, operation in wide temperature and pressure ranges and formation of harmless end products [ 75 , 76 ].

The enzyme with a high promise for dephenolisation of phenolics in water is tyrosinase KF1. The intermediate products are then removed through the addition of binding agents [ 77 ]. There has been a series of reported research works where enzymes have been used for the removal of phenolic compounds from wastewater [ 78 , 79 ]. They used tyrosinase isolated from Agaricus bisporus and immobilised it on polymer carriers, and inorganic coagulants to remove phenols from water.

Peroxidase extracted from horseradish, hydrogen peroxide and polyethylene glycol PEG was also used to catalyse phenol removal from simulated wastewater [ 80 ]. Adsorption is considered as one of the appropriate techniques for removal of phenolics from water because the technique is easy to design and operate. The technique produces no toxic wastes. The spent sorbent can serve as a source fuel to produce power [ 81 ].

Adsorption process involves the accumulation of the pollutant on the adsorbent's surface usually solid material. An appropriate adsorbent must be porous with large surface area, possess high hydrophobicity and have the ability to selectively accumulate the pollutant from water onto its surface.

Efficiency of the adsorption process is governed by [ 82 ]: Adsorbent's properties, i. The solution chemistry including its pH, temperature, degree of polarity, availability of other solutes competing for the adsorbent surface area and the concentration of the adsorbate. Nature of the adsorbate. This includes its degree of solubility in water, hydrophobicity, size and molecular weight.

Reference [ 82 ] found phenol adsorption process to be solely dependent on the initial pollutant concentration and speciation, which in turn depends on pH of the solution. Adsorption of pollutants from water is believed to be based on the following steps [ 83 ]: Movement of the pollutant molecules towards the adsorbent across the external boundary layer.

Various researchers have studied phenol adsorption from polluted water with different types of adsorbents. Phenol adsorption efficiency of different adsorbents including bagasse ash, activated carbon and charcoal from wastewater was studied by [ 84 ].

The adsorption efficiency was assessed based on the influence of pH, concentration of EDTA, anions and adsorbent dose. Removal efficiency was observed to increase with a decrease in the pH of the system. Effects of EDTA and nitrate ion content of the solution were identified as the factors that influenced the adsorption process.

Chloride ion, on the other hand, exerted a significant adverse effect on the efficiency of bagasse ash system. Film diffusion was noted to control the adsorption efficiencies of all the adsorbents used. The pollutant eradication process depended solely on its concentration, solution pH and temperature. A membrane is a specific type of a barrier that enables the separation of species in a gas or liquid through various mechanisms such as diffusion, sieving or sorption.

The selective separation occurs as a result of the semipermeable nature of the membranes. They get retained in the medium or on the membrane and later removed. Membrane separation is a general term used to encompass different types of separation processes that are characteristically the same or similar since they all use membranes.

The difference lies in the pore size of the membranes and the driving force involved in the separation process. The driving forces for separation may include high pressure application, the creation of concentration gradient and the use of electric potential [ 86 ]. These processes are categorised as microfiltration, ultrafiltration, nanofiltration and reverse osmosis [ 87 ]: Microfiltration: The membrane's pore size of this technique ranges from 0. It is normally used to filter suspended particles or colloidal solutions with large particles and bacteria.

Ultrafiltration: The pore diameter of this type of membrane ranges from 0. Nanofiltration: The pore size range of this type of membrane is 1—10 nm. It is used for brackish water desalination and removal of micropollutants or metal ions. Reverse osmosis: This refers to a membrane with pore diameters in the range of 0. An ideal membrane system must have good fluxes and be highly selective. It must have excellent thermal, chemical and mechanical stability with low tendency of foul formation.

Some advantages of membrane system of water purification include the following [ 87 ]: It has comparatively low energy requirements. The technology is also not without disadvantages. Some of these disadvantages include [ 88 ]: Many membranes composed of polymeric materials can decompose, or swell or become weak under harsh conditions, thereby weakening the selectivity, and shortening the lifespan of the membrane.

They found out that the total flux increased with increasing phenol content in the feed while the enrichment factor decreased. Use of ionic liquids in the form of bulk liquid membranes for the elimination of phenol from water has also been studied by Ng et al. The stability, membrane loss and phenol elimination efficiency of these liquids were compared. This liquid exhibited phenol extraction efficiency of These values were attained at optimum conditions of and rpm aqueous and membrane stirring speed, respectively.

This solvent was identified to possess higher hydrogen bonding, basicity and low viscosity compared to the other two solvents used. As a result, this process has been used to oxidise organic pollutants in aqueous solution to carbon dioxide and water. However, Fenton process has the disadvantage of the high cost of procuring the reactants hydrogen peroxide and iron II and sludge generation.

This process, often referred to as electrochemical catalysis, produces the iron II at a faster rate and thus promotes the production of hydroxyl radical for enhanced pollutant oxidation process [ 92 ]. They used a sacrificial iron anode as the source of iron II , added hydrogen peroxide to the system externally and used nitrogen gas sparging to stir the batch reactor. They observed that COD removal percentage increased with increasing current density, hydrogen peroxide concentration and sodium chloride concentrations but started decreasing, in all cases, beyond their respective optimum values.

In addition, consumption of energy and iron decreased as the initial pollutant phenol and sodium hydroxide concentrations were increased, but increased with an increase in the current density. They noticed that though increasing the current density caused a corresponding increase in the COD removal, it also resulted in increasing energy consumption.

Similarly, Rahmani et al. In this study, they applied a disposable iron anode as the source of ferrous iron and added the hydrogen peroxide manually. In an ion exchange process, an interchange of ions between two phases, usually a solid and a liquid phase, occurs. The ion change resin forms the solid phase while the sample under consideration is normally in the liquid phase.

Ions with charges similar to that of the resin are exchanged once the solution containing the ions comes into contact with the ion exchanger. The degree to which the ions are exchanged is governed by the concentration of the ions in solution ions to be exchanged with the resin and their degree of affinity for the ion exchange resin. The ion exchange process is reversible and is deemed as one of the unique technologies for wastewater treatment because of its high degree of recyclability and environmentally friendly nature [ 96 ].

The ions of the resin provide sites for ion exchange while the porous nature permits adsorption through hydrophobic interaction [ 97 ]. As an observation, phenol removal efficiency of both the strong and weak base ion exchange resins decreased significantly with increased initial phenol concentration from The process increased with increasing pH values from 9 to Ahmed et al. Extensive research has been performed on these compounds resulting in the elucidation of their structure or classification, their sources of entry into the aquatic environment and their reactivity or interaction with other components of the aquatic environment.

Research has also unveiled the significant toxic effects that these compounds exert on humans and wildlife upon exposure. Significant efforts have been made for the total elimination of phenolic compounds from water before use. Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution 3. Help us write another book on this subject and reach those readers.

Login to your personal dashboard for more detailed statistics on your publications. We are IntechOpen, the world's leading publisher of Open Access books. Built by scientists, for scientists. Phenol spray is safe to use at the recommend dose for a short time. But using too much or giving it to children younger than 3-years old can be unsafe.

And if your sore throat is accompanied by a fever, nausea, and vomiting, see a doctor as soon as possible before using phenol for throat soreness. Many phenol-based products that help relieve pain or irritation in or around your mouth can also be bought over-the-counter to numb tissues in the mouth and lips. These products are used as a short-term treatment for the symptoms of pharyngitis.

This happens when your throat gets inflamed from a bacterial or viral infection. Phenol-based products for mouth and throat pain are widely available and safe to use in small doses.

Phenol liquid is often used in molecular biology with trichloromethane and chloroform to separate RNA, DNA, or proteins, and isolate them in the pure form. This process is known as liquid-liquid extraction. The phenol-chloroform mixture separates molecules based on how soluble the tissue sample is in that solution. Soap containing phenol-based compounds is often called carbolic soap. It was also a common fixture in state schools in England and Scotland until the s. Carbolic soap is still widely used throughout the world.

It provides effective, low-cost hygiene to poverty-stricken communities. Over time, pure phenol has been replaced by some of its derivatives as an antiseptic. One derivative is n-hexylresorcinol, which can be found in cough drops. The compound, butylated hydroxytoluene BHT , replaced phenol as a food antioxidant.

Plant-based compounds containing phenol are known to be antioxidants. This means that they can stop the reaction of free radicals with other molecules in your body, preventing damage to your DNA as well as long-term health effects. Free radicals are molecules that have lost an electron and become unstable.

This makes them prone to react with and damage molecules like DNA. Free radicals sometimes cause the molecules they react with to create even more free radicals. Antioxidant molecules are like a barrier between free radicals and healthy molecules: antioxidants replace the missing electron and render it harmless. A animal review in Advances in Experimental Medicine and Biology suggested that getting phenols from a diet heavy in plants containing phenolic compounds and foods fortified with phenols helped strengthen the immune system and make cells more resistant to cancer throughout their life cycle.

According to a paper in Current Pharmaceutical Biotechnology, the complex structures of phenolic compounds can help make cancer cells more receptive to chemotherapy treatments. But it can be dangerous and even deadly in high amounts. Be careful in places that may contain high levels of phenol, such as industrial facilities. Learn about which foods have the most polyphenols. The phenols found in oregano may give it several health benefits. Here's the side effects of oregano herbal and essential oil, including its forms and….

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