China
Africa
Explore chapters and articles related to this topic
List of Chemical Substances
Published in T.S.S. Dikshith, and Safety, 2016
Carbaryl is a colorless to light tan or white or gray, solid crystals depending on the purity of the compound. The crystals are essentially odorless, and stable to heat, light, and acids, but are not stable under alkaline conditions. It is non-corrosive to metals, packaging materials, and application equipment. Carbaryl is classified as a GUP. It is sparingly soluble in water, but soluble in dimethylformamide, DMSO, acetone, cyclohexanone, isopropanol, and xylene. Carbaryl is a wide-spectrum carbamate insecticide that controls over 100 species of insects on citrus, fruit, cotton, forests, lawns, nuts, ornamentals, shade trees, and other crops, as well as on poultry, livestock, and pets. It is also used as a molluscicide and an acaricide. Carbaryl works whether it is ingested into the stomach of the pest or absorbed through direct contact. It is available as bait, dusts, wettable powders, granules, dispersions, and suspensions.
Enzymes Involved in the Bioremediation of Pesticides
Published in Pankaj Bhatt, Industrial Applications of Microbial Enzymes, 2023
Sajjad Ahmad, Pankaj Bhatt, Hafiz Waqas Ahmad, Dongming Cui, Jiatai Guo, Guohua Zhong, Jie Liu
Carbaryl is a broad-spectrum pesticide group of carbamates widely used in agriculture. Their residues accumulated in soil and water due to their more negligible removal and low solubility in water (Siampiringue et al., 2015). Li et al. (2019) identified the P450 enzyme from Xylaria sp. to degrade carbaryl residues and proposed their metabolic pathways. In liquid media, the degradation of carbaryl was achieved by the activation of the P450 enzyme. Moreover, the carbaryl esterase strikes on carbaryl and converts it into α-naphthol, which finally degrades into 1,4-naphthoquinone and benzoic acid through the activation of P450 and laccase enzymes.
Water Pollutants and Water Pollution
Published in Stanley E. Manahan, Environmental Chemistry, 2022
Carbaryl has been widely used as an insecticide on lawns or gardens. It has a low toxicity to mammals. Carbofuran has a high-water solubility and acts as a plant systemic insecticide. As a plant systemic insecticide, it is taken up by the roots and leaves of plants so that insects are poisoned by the plant material on which they feed. Pirimicarb has been widely used in agriculture as a systemic aphicide. Unlike many carbamates, it is rather persistent, with a strong tendency to bind to soil.
A Study on removal of Methylene Blue dye by photo catalysis integrated with nanofiltration using statistical and experimental approaches
Published in Environmental Technology, 2021
D. Naresh Yadav, K. Anand Kishore, Devendra Saroj
Cui et al. [11] studied the hybrid system (Photocatalysis and membrane separation) for the treatment of wastewater. In this work, the authors have reported that the combination of photocatalysis with the membrane-based filtration on a single set of unit shows many advantages in terms of lower footprint, maintenance, investment, etc. [12]. TiO2 deposited on the surface of the membrane, and its membrane pores lead to the membrane fouling. It was observed that in combined technique of photocatalysis and membrane filtration system developed by Yang et al and Rajeswari et al. [13], the TiO2 photocatalyst has been in the suspended form, and they have studied the removal of carbaryl, a carbamate pesticide using ozonation (O3), photolytic ozonation (O3/UV), and photocatalysis (TiO2/UV). They observed that Photocatalysis combined with ozonation process (TiO2/UV/O3) resulted in 92% of chemical oxygen demand (COD) reduction at pH 6.0 with 0.28 g/h of ozone and 1 g/L of TiO2 in 180 min.
A hybrid process for 2,4-dichlorophenoxy acetic acid herbicidal treatment and its microbial identification by MALDI-TOF mass spectrometry
Published in Environmental Technology, 2020
Gamze Dogdu Okcu, Hatice Eser Okten, Arda Yalcuk
Evaluating chemical and biological treatment efficiencies, the maximum COD removal efficiency for 2,4-D reached 62.47 ± 0.70% after 210 min with 1.5 g L−1 of TiO2 and UVA irradiation (Figure 6). When COD removal efficiencies in aerated and non-aerated biological reactors were examined, both reactors reached 78% after 5760 min, while in the aerated biological reactor, the COD removal efficiency was higher than that in the non-aerated reactor. Moreover, the COD removal was 67.75 ± 1.05% after 2880 min in the aerated reactor, while it was 49.71 ± 0.33% after 2880 min in the non-aerated biological reactor. Accordingly, it was verified that biological processes are slower than chemical processes and require longer times to reach the same removal efficiency as photocatalytic treatment [33]. Ballesteros-Martín et al. [9] reported that 31% of dissolved organic carbon (DOC) was removed in 140 min by the photo-Fenton reaction. Within 300 min, 90% DOC removal was achieved with the biologically active sludge process. A total of 200 mg L−1 dimethoate, oxydemethon-methyl, carbaryl and methidathion pesticide mixture was removed with the combined system within 420 min.
Combined microfiltration and adsorption process applied to public water supply treatment: water quality influence on pesticides removal
Published in Environmental Technology, 2020
Alcione Aparecida de Almeida Alves, Giselle Louise de Oliveira Ruiz, Thyara Campos Martins Nonato, Catiane Pelissari, Adriana Dervanoski, Maurício Luiz Sens
The mean pH value (7.29) of the CSTW fortified with pesticides carbamates was lower than the value of pHZCP (7.49). For pH values of the solution lower than pHZCP there will be a positive charge on the surface of the adsorbent [34]. The carbamates studied are classified as acidic herbicides (pKa carbaryl = 10.4; pKa carbofuran = 12.28 and pKa methomyl = 13.27). The higher the value of pKa, the weaker the acidic strength [35]. Carbaryl is the carbamate that has the highest acid content, followed by carbofuran and methomyl. This may also explain the higher adsorption capacity and chemical affinity of this carbamate for the adsorbent surface studied. The higher the acidic strength, the greater the ability to form negatively charged ions. The removal of the carbamates can also be related to their adsorption on the surface of the GAC by dispersive iterations due to the small difference between the pH of the solution (7.29) and pHZCP (7.49). When the pH of the solution is less than pKa of the herbicide, concentration of the adsorbates in undissociated form will be greater than the dissociated or anionic form. Wibowo et al. [36] studied the influence of surface chemistry and pH of the solution on the adsorption of benzene and toluene on activated carbons treated with nitric acid and thermally with nitrogen flow. The adsorbent used was the commercial F-400 coal. The treatment with acid caused the introduction of a significant number of acid oxygenated surface groups on the surface of the adsorbent. In this case, dispersive iterations were predominant because of the attraction between the orbital over the basal carbon plane and the electron density in the aromatic ring of benzene and toluene (iterations ).