Bispyribac nanopesticides from anionic and alkylammonium cationic clays for minimizing water environmental risks

Póster presentado en el XVI International Clay Conference from the Oceans to Space Granada, Spain, July 17-21, (2017)The development of new formulations based on clays as smart delivery systems or nanopesticides has become an interesting strategy for decreasing the environmental impact of pesticides [1-3]. Layered double hydroxides (LDHs) or anionic clays are especially convenient as host materials for anionic or acid pesticides to decreasetheir soil leaching losses, which areoftenvery high for this type of pesticides, particularly if they have high water solubility [4]. Alkylammonium cationic clays have also been shown as good carriers for pesticides in controlled release formulations [3,5]. We prepared and compared nanopesticide formulations of a very water soluble anionic herbicide, bispyribac (BIS), as LDH and as alkylammonium clay complexes, whose water and soil behaviour were lab-tested, as smart deliverysystemsto minimize their surface and ground water impact. The initial materials were LDH, lab-synthesized andcalcined at 500ºC (LDH500), and alkylammonium Cloisite10A (Clo10A) from BYK and supply by Comindex SA. The adsorption of bispyribac onLDH500 and Clo10A was firstly assayed. The LDH-BIS complex was prepared by regeneration of LDH500 in aqueous solution containing herbicide. The Clo-BIS complexes (20% w/w) were prepared in three ways: (i) ground mixing (GM); (ii) weak complex (WC) and (iii) strong complex (SC)3. The characterization of the LDH-BIS and Clo-BIS complexes were done by XRD, SEM and FTIR spectroscopy. The bispyribac slow release in water and the bispyribac leaching out from the soil column experiments were designed to compare the diverse nanopesticide complexes versus its technical and commercial products (Nominee 400SC).The L-type is othermsshowed that bispyribac adsorbed on both clays by specific mechanism and fitting to Langmuir model rendered a monolayer capacity much larger for LDH500 (Qm=1.3mmol/g) than for Clo10A (Qm=0.2 mmol/g). The XRD of LDH-BIS complex showed that layered structure was recovered and herbicidewas mainly in the interlayer with a basal spacing of 22.4 Å asan anion(̴ 25% of AEC), besides some carbonate and nitrate, as revealed by FT-IR. The XRD of Clo-BIS complexes showed that GM displayed an unchanged Clo10A (19 Å)basal spacing, whereas the other WC and SC complexes showed an increase and broadening of d001 around 21 Å indicating a disordered with different interlayering grade of bispyribac. The FT-IR spectra confirmed the presence of bispyribac as anion in all the complexes. The water release profiles showed the technical product and the Clo10A-BIS GM released immediately 98% and 100% of their initialherbicide content, whereas the LDH-BIS, and Clo10A-BIS SC and WC released immediately 18 23 and 65% reaching, after 120 h 68, 25 and 75%, thus displaying slow release profiles. The SC complex Clo10A-BIS could not be appropriated because of its very low final release. The soil column leaching studies revealed important differences among the diverse nanopesticides and with technical and commercial products. Those differences, as the corresponding water release profiles, were related with structure and interaction mechanism of bispyribac in the complexes. These results show that, combining aselection of carriers with diverse preparation modes, the resulting nanopesticides can offer a wide range of leaching risk minimization strategies. [1] Kah M., Beulke S., Tiede K., Hofmann T.(2013). Nanopesticides: State of knowledge, environmental fate, and exposure modeling. Crit. Rev.Environ.Sci.Technol. 43: 1823-1867. [2] Perez-de-Luque A., Hermosin M.C. (2013). Nanotechnology and its use in agriculture, In Bio-nanotechnology. A Revolution in Food, Biomedical and Health Sciences. Part 3, ed.: Bagachi D., Wiley-Blackwell, Chiechester, UK, pp. 383-398. [3] Cabrera A., Celis R., Hermosin M.C. (2015). Imazamox-clay complexes with chitosan- and iron(III)-modified smectites and their use in nanoformulations. Pest. Manag. Sci. 230:32-41. [4] Pavlovic I., Barriga C., Hermosin M.C., Cornejo J., Ulibarri M.A. (2005). Adsorption of acidic pesticides 2,4-D, Clopyralid and Picloram on calcined hydrotalcite. Appl. Clay Sci. 30: 125-133. [5] Carrizosa M.J., Hermosin M.C., Koskinen W.C., Cornejo J.(2003). Use of organosmectites to reduce leaching losses of acidic herbicides. Soil Sci. Soc. Am. J. 67:511-517.P11-AGR-7400, AGR-264 (PAIDI, Junta de Andalucia), CSIC-MINECO RECUPERA 2020 and AGL-2014-51897-R.N

Identification, characterization and adsorption properties of two organoclays for removal of bispyribac herbicide from water

Peer Reviewe

Cationic and anionic clay nanoformulations of imazamox for minimizing environmental risk

10 páginas.-- 8 figuras.-- 2 tablas.-- 45 referencias.-- Supplementary data to this article can be found online at https://doi.org/10.1016/j.clay.2018.10.014.A synthesized anionic clay (layered double hydroxide or LDH) and a commercial cationic organoclay (Cloisite 10A, Clo10A) were assayed as host nanocarriers for imazamox (Imz) herbicide. Imz-LDH complexes were obtained by direct synthesis (DS) and regeneration (RE), whereas Imz-Clo10A complexes were prepared by ground mixing (GM) and through methanol addition (weak [WC] and strong [SC] complexes). Characterization of the complexes showed that Imz was partially hosted in the interlayer structure of the resulting nanoherbicides, as anion or as neutral molecule, with some of the herbicide at the external surfaces, depending on the carrier and preparation. The nanoherbicides showed a total water release from 73 (Imz-LDH DS) to 98% (Imz-Clo10A GM) with an immediate release from 67 (Imz-LDH DS) to 93% (Imz-Clo10A GM), while technical Imz released instantaneously >98%. The herbicide maximum concentration in the leachates from Imz-treated soil columns decreased between 20 and 35% for nanoherbicides with respect to the technical Imz, and between 10 and 30% with respect to a commercial Imz formulation. Total herbicide soil leaching losses were reduced from 95 or 98%, for technical and commercial Imz, to 77–67% for nanoherbicides. Bioassays showed similar efficacy for nanoherbicides and commercial product. The diverse Imz-clay complexes are revealed as smart delivery systems for this systemic herbicide by decreasing Imz water pollution risk while maintaining efficacy, with the advantages of their soil compatible matrix and the possibility to be located at action point in the subsoilThis work was supported by Junta de Andalucía (Project P11-AGR-7400 ) and MINECO-CSIC (Project RECUPERA 2020 ), both co-financed by FEDER and FSE funds . Partial support by MINECO Projects AGL2014-51897-R and AGL2017-82141-R is also acknowledged. Prof Rachid Khatem thanks University of Mostaganem for Advanced Research Learning at Foreign Countries for supporting a stay at IRNAS-CSIC. Appendix APeer reviewe

Comparison of the systemic nanoherbicide Imazamox-LDH obtained by direct synthesis and reconstruction: preliminary results

Poster presentado en NanoTech France 2016 - Conference Program – Session II, P25Pesticides are widely used in modern agriculture but their needed intensive use causes environmental problems with toxicity and carcinogenicity consequences. This concern has generated research efforts to reduce pesticide environmental risks by developing formulations which gradually release the active ingredient supported on diverse materials (Perez-deLuque & Hermosin 2013). This type of slow-release formulation is fundamental for anionic herbicide as Imazamox, because its high soil mobility. The concept of nanopesticide has very recently appeared in the phytopathology (Kah et al. 2013, Perez-deLuque&Hermosin 2013, Cabrera et al. 2015) being specially interesting for the systemic pesticide, which are those needing to enter in the plant by leaves or roots to act versus pest. The objective of this work is to prepare Imazamox-LDH as nanocomponent, to be used as smart delivery system that allows to remain imazamox in the target site (rizosphere at subsoil) and to minimize its environmental risk. The complexes are prepared by direct synthesis (DS) or coprecipitation and by regeneration (RE) of calcined HT at 500ºC in aqueous solution containing herbicide at appropriated pH. The imazamox content in the nanoherbicides are determined by dissolving in acid and then quantified by HPLC. The content of Imazamox in those samples was 35% for DS and 10% (w/w) for RE. Fig. 1 shows the XRD patterns of both nanoherbicide obtained, where the most important diffraction peaks of the hydrotalcite–like structure are developed.PO11-AGR-7400 (Junta de Andalucia) & RECUPERA 2020 (MINECO-CSIC)Peer reviewe

Use of synthetic clay for Removal of Diclofenac Anti-inflammatory

The removal of diclofenac by sorption on a synthetic hydrotalcite and on its calcined product was investigated. The solid [Mg-Al-CO3], prepared by cooprecipitation at constant pH, its calcined mixed oxide was obtained; both solid were characterized by X-ray diffraction and infrared spectroscopy (FTIR). The interaction of these materials with diclofenac shows that the kinetics of sorption was fast and followed the second order model. The effects on the diclofenac concentration, sorbent concentration and temperature were studied. The sorption capacity of the calcined hydrotalcite was close to 1.9 mmole g-1, which represents only 66% of the AEC, but at the concentrations measured that amount represents up 95% of the diclofenac present in solution in the case of HT-C. This suggests that, particularly HT-C could to constitute interesting adsorbent for the removal of diclofenac. Recycling by restitution and calcination-rebuilding should support the recovery of this pollutant

Anionic clay and cationic organoclay as nanocarriers in smart delivery systems of the herbicide imazamox

Conferencias presentada en la S 12. Clays, zeolites and nanostructured minerals: from mineralogy to applications in industry and environment de las 2nd European Mineralogical Conference, emc2016 “Minerals, fluids and rocks: alphabet and words of planet Earth”,11-15 September 2016 Rimini, (Italy)Peer Reviewe

Work of soil and risks of agricultural erosion: Case of the itinerary technical cereal on tray of Mostaganem-Northwest Algeria

With a semi-arid Mediterranean climate and viticulture vocation, the tray of Mostaganem (North-West of Algeria) has become a region of great crops. Subject to increase mechanization and inappropriate tillage practices, farm lands are exposed to erosion that seriously weighs the physical and socio-economic contexts. An itinerary technique (cereal) is chosen to study along the slope, surface and deep structural changes of soil, humidity and the fine particles (<2 μm). Thus, consideration of the surface shows a strong soil erodibility partly linked to the action of implements and a rain erosivity accentuated by lack of vegetation in the rainy season.Culural profiles observations show the small depth of tillage affecting mostly superior horizon. Average horizon, wet, rich in fine particles and barely reached by tools impedes any move to lower horizon which is very compact without variability. With this kind of technical itinerary, fine elements losses estimated to (3 t/ha/year) result closely from the characteristics of the physical environment but also the conditions of its exploitation. In case of more important spatial-temporal unit’s extrapolation, the consequences will be even more harmful if improvement actions are not undertaken