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Topic Review
Characteristics, Concentration, Toxicity of ECs in Water Bodies
Emerging contaminants (ECs) are causing negative effects on the environment and even on people, so their removal has become a priority worldwide. ECs are organic, pseudo-persistent, and unregulated “new” contaminants detected in water/wastewater in trace concentrations (ng/L–µg/L).
  • 160
  • 05 May 2023
Topic Review
Characterization of the Oxidation Products of Lipids
Phototrophic organisms (mainly green plants, algae, cyanobacteria and some protists) carry out photosynthesis that is, conversion of sunlight energy, carbon dioxide and water into organic materials. Due to the generation of highly reactive oxygen species (ROS) during photosynthetic electron transport, these organisms are particularly sensitive to oxidative damages. Lipids (hydrocarbons, pigments, terpenoids, free fatty acids, acylglycerides, phospholipids, galactolipids, cutins, suberins and waxes) are important components of phototrophic organisms, accounting for 16–26% of organic content in phytoplankton and up to 45% in the green alga Botryococcus Braunii.  The applications of gas chromatography-mass spectrometry techniques for the characterization of photooxidation and autoxidation products of unsaturated lipids of senescent phototrophic organisms will be introduced. 
  • 508
  • 21 Apr 2022
Topic Review
Chelating Agents in Soil Remediation
The Fenton process is an efficient treatment for removing many organics pollutants in aqueous systems at acidic pH (2.8-3.5). However, the in-situ application of this technology for soil remediation (where pHs around neutrality are required) presents important limitations, such as catalyst (iron) availability and oxidant (H2O2) stability. The addition of chelating agents (CAs) makes iron soluble at circumneutral pH by forming complexes with Fe, and thus, enabling Fenton reactions under these conditions. This strategy, called chelate-modified Fenton process (MF), can be employed to overcome the challenges identified in conventional Fenton.
  • 1.8K
  • 09 Aug 2021
Topic Review
Chemical Alternatives for Fixing Carbon Dioxide
Carbon is the most important element of organic matter, forming the major part of its dry weight. Elemental carbon exists in the atmosphere as carbon dioxide (CO2) and is dissolved in water, rocks, and soils as carbonic acid (H2CO3), bicarbonates, and carbonates. In fossil fuels, it exists as carbon rings or chains and in biomolecules such as nucleic acids, carbohydrates, proteins, and lipids. Atmospheric CO2 is the major cause for global warming through the greenhouse effect; hence, carbon dioxide emissions must be strictly regulated to minimize the greenhouse effect.
  • 907
  • 13 Apr 2022
Topic Review
Chemical Analysis of Organochlorine Pesticide in Agricultural Soils
Soil constitutes the central environmental compartment that, primarily due to anthropogenic activities, is the recipient of several contaminants. Among these are organochlorine pesticides (OCPs), which are of major concern, even though they were banned decades ago due to their persistence and the health effects they can elicit. A plethora of methods have been developed and applied for OCP analysis in environmental matrices (i.e., soil and sediment). The entire chemical analysis involves several crucial stages such as sample preparation and analyte chromatographic separation, including detection, quantification, and data analysis. Among them, the sample preparation step is considered as the most critical point to be made prior to instrumental analysis. In particular, the development of methodologies for determining pesticides in soil is a challenging task. As a result of the complexity and the physicochemical characteristics of such types of samples, two main factors should be considered: (a) the extremely low concentration of banned OCPs in soil samples. This is the reason why extremely sensitive analytical methods (including, in many cases, enrichment techniques) are required for the detection and quantification of these analytes at such levels, and (b) the strong binding of OCPs to soil.
  • 741
  • 31 May 2022
Topic Review
Chemical and Biological Degradation for Perfluorooctanoic Acid
Perfluorooctanoic acid (PFOA) is a perfluoro compound that contains an eight-carbon perfluoroalkyl chain followed by a carboxylic acid function group. It has found applications in water-resistant coating and is produced either by degrading other long-chain perfluorinated carboxylic acids or fluorotelomer alcohol. PFOA is challenging to further degrade during water treatment processes, leading to its accumulation in natural systems and causing contamination. Research has been conducted to develop several methods for its removal from the water system.
  • 290
  • 01 Dec 2023
Topic Review
Chemical Coagulation–Flocculation Technologies and Their Performance
The permanent demand of modern society for water consumption across different industrial and domestic activities involves an increasing requirement for effective facilities that can ensure the treatment of the produced WW (Wastewater) for onsite reuse, recycling, and safe/non-polluting discharge of the final effluents to natural aquatic environments. A few fundamental aspects of WW treatment using different physical, chemical, and biological processes were discussed, with the central goal being focused on the coagulation–flocculation step. Therefore, the role of the coagulation–flocculation step when applied to the treatment of colored textile WW and the advantages and disadvantages of using different chemicals as coagulation–flocculation agents in some industrial WW treatment systems as well as hybrid materials were presented in association with their increased efficiency in comparison to conventional ones.
  • 262
  • 15 Apr 2024
Topic Review
Chemical Rings
The epoxidized group, also known as the oxirane group, can be considered as one of the most crucial rings in chemistry. Due to the high ring strain and the polarization of the C–O bond in this three-membered ring, several reactions can be carried out. One can see such a functional group as a crucial intermediate in fuels, polymers, materials, fine chemistry, etc. 
  • 849
  • 30 Aug 2021
Topic Review
Chemical Waste
Chemical waste is waste , that is made from chemicals that are mostly produced by large factories. Chemical waste can damage , the environment and cause health problems and as such may fall under regulations such as COSHH in the United Kingdom or the Clean Water Act and Resource Conservation and Recovery Act in the United States . In the U.S., the Environmental Protection Agency (EPA) and the Occupational Safety and Health Administration (OSHA), as well as state and local regulations also regulate chemical use and disposal. The disposal and handling of radioactive waste is a particular focus for regulatory bodies due to the environmental and health risks of radiation and the challenges of safe disposal. Chemical waste may or may not be classed as hazardous waste. A chemical hazardous waste is a solid, liquid, or gaseous material that displays either a "Hazardous Characteristic" or is specifically "listed" by name as hazardous waste. There are four characteristics chemical wastes may have to be considered hazardous. These are ignitability, corrosivity, reactivity, and toxicity. This type of hazardous waste must be categorized as to its identity, constituents, and hazards so that it may be safely handled and managed. Chemical waste is a broad term and encompasses many types of materials. The Material Safety Data Sheet (MSDS), Product data sheet or Label can provide a list of constituents. These sources should state whether this chemical waste is a waste that needs special disposal.
  • 1.6K
  • 24 Oct 2022
Topic Review
Chemical, Biological, Radiological, and Nuclear Agents
Combating chemical, biological, radiological, and nuclear (CBRN) threats with novel solutions reduces disasters and accident risks and, at the same time, aids sustainability.
  • 524
  • 16 Feb 2023
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