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Exploitation of Silver Nanoparticles in Bioremediation
Published in Ram Naresh Bharagava, Sandhya Mishra, Ganesh Dattatraya Saratale, Rijuta Ganesh Saratale, Luiz Fernando Romanholo Ferreira, Bioremediation, 2022
Punabati Heisnam, Abhinash Moirangthem, Yengkhom Disco Singh, Pranab Dutta, Chabungbam Victoria Devi, B.N. Hazarika
Moreover, biological methods are also reliable in ‘bottom-up approach’, which provides an important alternate pathway for the green synthesis of nanomaterials. The microorganisms include bacteria, fungi, enzymes and plant extracts that can be used for the synthesis of metal nanoparticles such as silver. PAHs (polycyclic aromatic hydrocarbons) are an organic contaminant (e.g. phenanthrene, pyrene and naphthalene) mainly caused by unfinished fossil fuel burning, old storage tanks seepage, spilling of oils, domestic waste, etc. The PAHs can remain for a longer period of time in the environment and are unmanageable, so they produce harmful organic pollutants that cause mutant disorders and that are carcinogenic in nature. Culturing of pure bacteria in contaminated paths helps in the degradation and uptake of PAHs.
New Technologies Used in Wastewater Treatment
Published in Pankaj Chowdhary, Sujata Mani, New Technologies for Reclamation of Industrial Wastewater, 2021
Polycyclic Aromatic hydrocarbons (PAHs) are another type of pollutants found frequently in industrial wastewaters—in petroleum products, coal conversion industries, and organic material synthesis. Polycyclic aromatic compounds are recalcitrant compounds that do not degrade and persists in the environment for an extended period, consequently causing toxic and hazardous effects on humans and the environment. One of the most toxic PAHs is a naphthalene compound. Its removal test was performed using Streptomyces sp. strain through bioaugmentation in the wastewater of coal gasification in a membrane bioreactor, and results showed its significant elimination from wastewater (Xu et al., 2015). Zhu et al. (2015) performed a similar test on the bioaugmentation of cooking wastewater with a developed consortium of five strains of Pseudomonas sp. and Paracoccus denitificans and this bioaugmentation process assisted the removal of pollutants carbazole, naphthalene, phenol, pyridine, and quinoline found in cooking wastewater. In another study, phenol present in wastewater from coal gasification was removed using a mixture of phenol-degrading bacterial on biological contact oxidation reactor, but the bacterial species name was not revealed (Fang et al., 2013).
Biodegradation-based remediation – overview and case studies
Published in Katalin Gruiz, Tamás Meggyes, Éva Fenyvesi, Engineering Tools for Environmental Risk Management – 4, 2019
M. Molnár, K. Gruiz, É. Fenyvesi
Polycyclic aromatic hydrocarbons (PAHs) are also widely distributed environmental contaminants that have harmful biological effects including acute and chronic toxicity, mutagenicity, and carcinogenicity. In the case of these contaminants the effect of chemical structure on biodegradability in soil is also obvious. Anthracene, phenantrene, and acenaphthylene contain three rings and are biodegraded at reasonable rates when oxygen is present. Other compounds with four rings in contrast are highly persistent (Alexander, 1994). For example, anthracene biodegradation by Gram-negative, Gram-positive bacteria, and numerous fungi has been reported. Bacteria initiate anthracene degradation by hydroxylation of the aromatic ring to yield cis-1,2-dihydroanthracene-1,2-diol. This intermediate is converted to anthracene-1,2-diol, which is cleaved at the meta position to yield 4-(2-hydroxynaph-3-yl)-2-oxobut-3-enoate (see Figure 5.9). This compound may spontaneously rearrange to form 6,7-benzocoumarin or be converted to 3-hydroxy-2-naphthoate from which degradation proceeds through 2,3-dihydroxynaphthalene to phthalate. This pathway has been identified in different bacteria such as Pseudomonas, Sphingomonas, Rhodococcus, Mycobacterium, and Bacillus sp. (EAWAG, 2018).
Environmental remediation using metals and inorganic and organic materials: a review
Published in Journal of Environmental Science and Health, Part C, 2022
Haragobinda Srichandan, Puneet Kumar Singh, Pankaj Kumar Parhi, Pratikhya Mohanty, Tapan Kumar Adhya, Ritesh Pattnaik, Snehasish Mishra, Pranab Kumar Hota
Strategies for soil remediation include chemical fixation, chemical oxidation, chemical leaching and electrokinetic approaches. FeSO4 solution as a chemical fixation agent is used to remove As from soil wherein insoluble phases like FeAsSO4 or FeAsSO4.2H2O formed thereby preventing As from ecological risk.15,17 Along with primarily chemical oxidation employed to remediate polycyclic aromatic hydrocarbons (PAHs) in soil, the use of ozone, permanganate, persulphate and peroxides as oxidants for PAHs removal are reported.16 Use of chemical reagents like diluted sulfuric, nitric, hydrochloric and phosphoric acids, bio-generated Fe3+ and sulfuric acid, and supercritical CO2 for chemical leaching of toxic metals (As, Pb, Cd, Zn, Ni, V, etc.) and organic pollutants are well established.15,18–20 Solubilized metals in leachate can be further recovered suitably through solvent extraction, selective precipitation, etc. In electrokinetic remediation, an external electric field is applied by maintaining anode and cathode around the soil. The negatively charged particles/pollutants migrate toward anode while the positive toward the cathode.21 As this needs maintaining the soil pH, suitable buffer solution may be needed.22
Seasonal pollution characteristics, source apportionment and health risks of PM2.5-bound polycyclic aromatic hydrocarbons in an industrial city in northwestern China
Published in Human and Ecological Risk Assessment: An International Journal, 2021
Guozhen Zhang, Kejing Ma, Lijuan Sun, Pengfei Liu, Yongli Yue
With the development of industry and the expansion of cities, air pollution characterized by PM2.5 (ambient fine particles with aerodynamic diameters less than 2.5 mm) has increased. PM2.5 is of concern due to its small particle size, toxic and harmful components, long life in the atmosphere and long distance transport potential. Among the toxic components, polycyclic aromatic hydrocarbons (PAHs) are of particular concern because of their carcinogenic, teratogenic, mutagenic and DNA damage-causing effects. PAHs are hydrocarbons containing two or more benzene rings and include 150 species. PAHs containing four to six rings are highly toxic (Shen et al. 2013). Sixteen PAHs have been listed as priority pollutants by the United States Environmental Protection Agency (US EPA) (Vejerano et al. 2013; Li et al. 2014). PAHs are mainly derived from natural sources such as forest fires, volcanic eruptions, untapped coal and oil and anthropogenic sources such as incomplete combustion of fossil fuels and biomass, automobile exhaust emissions, and industrial emissions (Kong et al. 2010; Shakya and Griffin 2010; Orecchio et al. 2016). The composition and toxicity of PAHs vary greatly due to their different sources.
Different bioavailability of phenanthrene to two bacterial species and effects of trehalose lipids on the bioavailability
Published in Journal of Environmental Science and Health, Part A, 2020
Jae-Soo Chang, Daniel K. Cha, Mark Radosevich, Yan Jin
Bioremediation of sites contaminated with polycyclic aromatic hydrocarbons (PAHs) has been considered as an attractive option to remove the organic pollutants.[1,2] However, it may be significantly affected by the sorption process due to the hydrophobic nature and low solubility of the organic compounds.[3–6] It has been generally assumed that organic substrates become less available to microorganisms as they are sorbed to the solid phase, and degradation of such substrates are directly related to their dissolved concentrations.[7–9] In contrast, other studies have demonstrated that microorganisms are not only able to degrade dissolved contaminants, but are also able to access and utilize the compounds in the sorbed phase.[9–13] These studies suggest that reduced biodegradation of contaminants due to the sorption depends on microorganism characteristics and that mass transfer is not a limiting factor for some bacteria to access the substrates in the sorbed phase.[14]