Controlled Release of Three Herbicides by the Kraft Lignin PC940C

Riggle, Bruce D.; Penner, Donald

doi:10.1017/s0043174500074609

Cited by 35 publications

(24 citation statements)

References 10 publications

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“…When MEFs were applied, the herbicide eluted was significantly less than that from the CF ( Table 2), the rest remaining distributed among the different depths in the soil column ( Table 4). This is supported by previous studies, which indicated that alachlor leaching can be reduced by microencapsulation techniques (6,(17)(18)(19)(20). As observed in Figure 2a, the maximum of the BTC obtained from CF occurs earlier (about 4 pore volumes) than for the rest of the formulations, with the exception of A8, indicating that the microencapsulated formulations result in higher soil retention and slower release.…”

Section: Alachlor Encapsulation In Ethylcellulose Microspheressupporting

confidence: 87%

Ethylcellulose Formulations for Controlled Release of the Herbicide Alachlor in a Sandy Soil

Sopeña

Cabrera

Maqueda

et al. 2007

J. Agric. Food Chem.

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The development of controlled-release formulations of alachlor to diminish its leaching in sandy soils, avoiding groundwater contamination and maintaining its efficacy, was studied. For this purpose, ethylcellulose (EC) microencapsulated formulations (MEFs) of alachlor were prepared under different conditions and applied to soil columns to study their mobility. The results show that in all cases the release into water of alachlor from MEFs was retarded when compared with commercial formulation. Total leaching losses in soil columns were reduced to 59% from 98%. The mobility of alachlor from EC microspheres into soil columns has been greatly diminished in comparison with its current commercial formulation (CF), above all with increasing EC/herbicide ratios. Distribution of alachlor applied as MEFs at different depths in the soil was higher in the soil surface (66.3-81.3% of herbicide applied at the first 12 cm). In contrast, the residues from CF along the complete soil column were only 20.4%. From the results of bioassays, MEFs showed a higher efficacy than CF at 30 days after the treatment. The use of ME formulations could provide an advantage in minimizing the risk of groundwater contamination by alachlor and reducing the application rates, as a result of maintaining the desired concentration of the herbicide in the top soil layer, obtaining longer periods of weed control.

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Section: Alachlor Encapsulation In Ethylcellulose Microspheressupporting

confidence: 87%

Ethylcellulose Formulations for Controlled Release of the Herbicide Alachlor in a Sandy Soil

Sopeña

Cabrera

Maqueda

et al. 2007

J. Agric. Food Chem.

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“…Dorado et al (2005) reported a similar result for the sorption of both pesticides by soils modifi ed with manure and straw. Th e partial sorption re- versibility of linuron from lignins could be due to the sorption of linuron by low-molecular-weight water-soluble materials (Riggle and Penner, 1988;Sánchez-Camazano et al, 2000). Figure 2 shows the isotherms corresponding to the sorption of paraquat (cationic) and dicamba (anionic) by the lignins and cellulose.…”

Section: Sorption-desorption Of Non-ionic Pesticides By Organic Matermentioning

confidence: 99%

“…However, studies on pesticides, compounds with large complex structures with different functional groups able to interact with such organic components, are less common. In general, the aim of the studies performed has been to determine the behavior of lignins as pesticide support in controlled‐release formulations (Riggle and Penner, 1987, 1988; Ferraz et al, 1997) or to evaluate their influence as a precursor of the soil organic matter (OM) in the determination of pesticide behavior in soils (Benoit et al, 1999; Beulke et al, 2005). The mechanism of action governing the retention of pesticide by these materials has been scarcely addressed (Torrents et al, 1997).…”

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confidence: 99%

Physicochemical Study of the Sorption of Pesticides by Wood Components

et al. 2009

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The sorption-desorption and interaction mechanisms of three non-ionic (linuron, alachlor, and metalaxyl) and two ionic (paraquat and dicamba) pesticides by three commercial lignins (hydrophobic macromolecule) and cellulose (hydrophilic macromolecule) as wood components were studied. Wood is a low-cost and environmentally friendly material proposed in recent years to immobilize pesticides in soils. The influence of sorbent and pesticide properties and the identification of the functional groups of the organic molecules involved in sorption were evaluated by a statistical approach and by Fourier transform infrared spectroscopy. The sorption isotherms of non-ionic pesticides by the lignins and cellulose fit the Freundlich model, and those of the ionic pesticides also fit the Langmuir model. The sorption constants of pesticides by cellulose were 62-, 9-, 24-, 119-, and 3-fold lower than those for the sorption by lignins. A predictive model of pesticide sorption indicated that 88.5% of the variability in the sorption coefficient normalized to the organic carbon content could be explained in terms of the variability of the polarity index and the octanol-water partition coefficient of sorbent and sorbate. The greater irreversibility observed for ionic pesticides was attributed to the involvement of simultaneous interaction mechanisms. The results obtained contribute the knowledge of sorption capacity of pesticides by lignin/cellulose, the main components of woods and ubiquitous materials in the environment.

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“…11 Furthermore, a controlled‐release system not only increases the effectiveness of the active agents, but it also facilitates minimizing the amount of chemicals applied to the soil, and thus, decreases the likelihood of damage to the environment. 12 Unlike conventional products, controlled‐release materials are safer for those who handle them or come in contact with treated crops during harvesting or storage. 13 The application of controlled release technology has been slow to reach commercialization, despite interesting research and development work by the major agrochemical companies over the last 10 years.…”

Section: Introductionmentioning

confidence: 99%

Control release of some pesticides from starch/(ethylene glycol‐co‐methacrylic acid) copolymers prepared by γ‐irradiation

El‐Mohdy

Hegazy

El-Nesr

et al. 2011

J of Applied Polymer Sci

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Starch/(Ethylene glycol-co-Methacrylic acid) [Starch/(EG-co-MAA)] hydrogels were designed for controlled delivery of pesticides, such as Fluometuron (FH); Thiophanate Methyl (TF) and Trifluralin (TI) which are use in the agricultural field. The delivery device was prepared by using c-irradiation and was characterized by FTIR, DSC, and SEM. The swelling behavior of hydrogels as a function of copolymer composition and irradiation dose was detected. This article discusses the swelling kinetics of polymer matrix and release dynamics of Trifluralin from hydrogels for the evaluation of the diffusion mechanism and diffusion coefficients. The values of the diffusion exponent 'n' for both the swelling of hydrogels and the release of Trifluralin from the hydrogels have been observed between 0.56 and 0.86 when the MAA content in the polymers was varied from 20 to 80 wt %, respectively. It is inferred from the values of the 'n' that non-Fickian diffusion mechanism has occurred for different EG/MAA compositions. The release rate from matri-ces prepared under different conditions was studied to determine which factors have the most affect and control over the hydrogel matrix release property. The preparation conditions such as EG/MAA hydrogel composition, pesticide concentration, type of pesticide and irradiation dose greatly affect the pesticide release rate, which also influenced by the pH and temperature of the matrix-surrounding medium. The pesticide release rate decreased as the irradiation dose and pH increased, but it increased as the MAA content, pesticide concentration and temperature increased. The release rate of Trifluralin is the highest one, whereas the Fluometuron is the lowest. The properties of the prepared hydrogels may make them acceptable for practical use as bioactive controlled release matrices. V C 2011 Wiley Periodicals, Inc. J Appl Polym Sci 122: [1500][1501][1502][1503][1504][1505][1506][1507][1508][1509] 2011

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Controlled Release of Three Herbicides by the Kraft Lignin PC940C

Cited by 35 publications

References 10 publications

Ethylcellulose Formulations for Controlled Release of the Herbicide Alachlor in a Sandy Soil

Ethylcellulose Formulations for Controlled Release of the Herbicide Alachlor in a Sandy Soil

Physicochemical Study of the Sorption of Pesticides by Wood Components

Control release of some pesticides from starch/(ethylene glycol‐co‐methacrylic acid) copolymers prepared by γ‐irradiation

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