Synthesis and characterization of [4-(2,4-dichlorophenoxybutyrate)-zinc layered hydroxide] nanohybrid

A new layered organic–inorganic nanohybrid material in which an agrochemical, 4-(2,4-dichlorophenoxy)butyrate (DPBA) is intercalated into inorganic interlayers of zinclayeredhydroxide (ZLH) was synthesized by direct reaction of aqueous DPBA solution with zinc oxide. The resulting nanohybrid is composed of the organic moieties, DPBA sandwiched between ZLH inorganic interlayers. The nanohybrid afforded well ordered crystalline layered structure, a basal spacing of 29.6 Å, 23.5% carbon (w/w) and 47.9% (w/w) loading of DPBA. FTIR study shows that the absorption bands of the resulting nanohybrid composed the FTIR characteristics of both the DPBA and ZLH which further confirmed the intercalation episode. The intercalated organic moiety in the form of nanohybrid is thermally more stable than its sodium salt. Scanning electron micrograph shows the ZnO precursor has very fine granular structure and transformed into a flake-like when the nanohybrid is formed. This work shows that the nanohybrid of DPBA-ZLH can be synthesized using simple, direct reaction of ZnO and DPBA under aqueous environment for the formation of a new generation of agrochemical

Removal of Zinc by the Moss Calymperes delessertii Besch

Studies were conducted to assess the capability of a moss, Calymperes delessertii Besch, to remove zinc from solutions. In the batch experiments, parameters studied included effect of pH and initial zinc concentration on sorption. A series of fixed bed experiments were performed to study the system under dynamic conditions. The bed depth service time (BDST) model proposedn by Hutchins was successfully applied to the system. The fixed bed experiments were also carried out using waste water from a zinc plating factory and results indicated that moss columns could be used in a clean-up system to remove zinc from electroplating waste water

Synthesis and characterization of (zinc-layered-gallate) nanohybrid using structural memory effect

The memory effect of calcined zinc hydroxide nitrate, with gallate anion solutions, was studied. The layered hydroxide salt material, zinc hydroxide nitrate was heat-treated at 150–800 °C. XRD analysis showed the growth of the calcined materials in both thickness and diameter occurring simultaneously with increasing calcination temperature. Surface area analysis confirmed this growth. The rehydration behavior of the calcined material was investigated by placing the material in a solution containing gallate anions. The best result for layered hydroxide salt phase reconstruction was obtained for a sample heated at 500 °C and treated with 0.1 mol L−1 anion. PXRD analysis showed the formation of a layered structure material after rehydration process. FTIR and TG confirmed the formation of the host–guest nanohybrid material produced

LDH-intercalated D-gluconate: generation of a new food additive-inorganic nanohybrid compound

Intercalation of d-gluconate into the interlamellae of zinc–aluminum-layered double hydroxide for the formation of a food additive-inorganic layered nanohybrid was accomplished by both direct (co-precipitation) and indirect (ion-exchange) methods. Powder X-ray diffraction (PXRD) together with CHNS and Fourier transform infrared (FTIR) analyses showed that the hybridization of d-gluconate with pure phase and good crystallinity was successfully accomplished by a direct method within ranges of pH 7.5–10, Zn to Al initial molar ratio of 2–5 and DG concentration of 0.05–0.3 M. The same nanohybrid compound was also prepared using an indirect ion-exchange method by contacting the pre-prepared LDH with 0.1 M DG for 80 min. The basal spacing of the nanohybrid synthesized by the direct method ranged between 9 and 12.0 Å while that synthesized by the indirect ion-exchange method was 14.0 Å. The crystallinity of the latter was higher than the former and it inherited the crystallinity of the precursor. This work shows that a food additive, such as d-gluconate, can be hybridized into an inorganic host for the formation of a new nanohybrid compound, which can be used to regulate the release of acidity in the food industry

Controlled release formulation of agrochemical pesticide based on 4-(2,4-dichlorophenoxy)butyrate nanohybrid

Hybridization of beneficial organic guest with inorganic host affords scientists an opportunity to synthesize various combinations of new organic-inorganic nanohybrids with various potential applications, especially for controlled delivery of beneficial agent and storage. A new layered organic-inorganic nanohybrid material containing an agrochemical, 4-(2,4-dichlorophenoxy)butyrate (DPBA) in Zn-Al-layered double hydroxide inorganic interlayer was synthesised by direct and indirect methods. Both methods yielded mesoporous-type, phase pure, well-ordered layered nanohybrids with similar basal spacing of 28.5-28.7 angstroms and organic loading of around 54.3%. Compared to the material prepared by direct method, the ion exchanged product inherited more of the host's properties especially the pore structure and the organic moiety is also more easily released. This shows that the method of preparation plays an important role in determining the resulting physicochemical properties, in particular the release property and therefore can be used as a means to tune up the release property of the beneficial agent

Synthesis of dichlorprop-Zn/Al-hydrotalcite nanohybrid and its controlled release property

New phase-pure nanohybrids of dichlorprop[2(2,4-dichlorophenoxy)propionate]-intercalated Zn/Al-LDH were successfully prepared using either co-precipitation or ion exchange methods. The basal spacing expansion from 8.9 Å in the layered double hydroxide (LDH) to 18.7 and 21.7 Å of the nanohybrids was observed. This together with FTIR, DTG/TGA and compositional studies show that dichlorprop was successfully intercalated into the Zn/Al-layered double hydroxides interlayer. Release study of dichlorprop showed that it is dependent on the concentration of the incoming ionic species and governed by the pseudo-second order kinetic. This study suggests that the layered double hydroxide might be used as a matrix for controlled release formulation for a herbicide, dichlorprop and the release of the herbicide can be tuned using parameters such as method of synthesis and the concentration of the incoming ionic species to be ion exchange with. This is towards new generation of agrochemicals which are safer as well as user- and environmentally-friendly

Inorganic-based phytohormone delivery vector of 2-chloroethylphosphonate nanohybrid, a new stimulating compound with controlled release property to increase latex production.

New inorganic-based phytohormone delivery system, a stimulating compound to increase latex production was developed through hybridisation of 2-chloroethylphosphonic acid (ethephon) into the interlayer of Zn–Al-layered (ZAL) double hydroxide. The hybridisation product, ZADO, was synthesised using co-precipitation technique at pH 7.5, 0.08 M ethephon and initial molar ratio of Zn to Al, R = 4. The resulting material has a basal spacing of 11.5 Å and Fourier transform infrared spectra further supported the hybridisation episode of ethephon into the ZAL. The release behaviour of the active agent, ethephon from the nanohybrid was found to be of controlled manner, governed by pseudo-second order kinetics. These results indicate that it is possible to design and develop a new delivery system of a phytohormone, [ethephon (2-chloroethylphosphonate)] with controlled release property to increase latex production of rubber tree (Hevea brasiliensis)

Thermal decomposition pathway of undoped and doped zinc layered gallate nanohybrid with Fe3+, Co2+ and Ni2+ to produce mesoporous and high pore volume carbon material.

A series of brucite-like materials, undoped and doped zinc layered hydroxide nitrate with 2% (molar) Fe3+, Co2+ and Ni2+ were synthesized. Organic–inorganic nanohybrid material with gallate anion as a guest, and zinc hydroxide nitrate, as an inorganic layered host was prepared by the ion-exchange method. The nanohybrid materials were heat-treated at various temperatures, 400–700 °C. X-ray diffraction, thermal analysis and also Fourier transform infrared results showed that incorporation of the doping agents within the zinc layered hydroxide salt layers has enhanced the heat-resistivity of the nanohybrid materials in the thermal decomposition pathway. Porous carbon materials can be obtained from the heat-treating the nanohybrids at 600 and 700 °C. Calcination of the nanohybrids at 700 °C under nitrogen atmosphere produces mesoporous and high pore volume carbon materials

Bacillus cereus as a biotemplating agent for the synthesis of zinc oxide with raspberry- and plate-like structures

Currently the development of green chemistry approach with the use of biomaterial-based activities of microbial cells in the synthesis of various nanostructures has attracted a great attention. In this study, we report on the use of bacterium, Bacillus cereus as a biotemplating agent for the formation of zinc oxide nanoparticles with raspberry- and plate-like structures through a simple thermal decomposition of zinc acetate by maintaining the original pH of the reaction mixtures. Possible mechanism on the formation of the nanostructures is proposed based on the surface chemistry and biochemistry processes involved organic–inorganic interactions between zinc oxide and the microbial cells

Effects of monoculture and polyculture farming in oil palm smallholdings on terrestrial arthropod diversity

Oil palm agriculture has become one of the economic mainstays for biodiversity-rich countries in the tropics. The conversion of native forests to oil palm monoculture plantation has caused unprecedented biodiversity loss in Southeast Asia. Little is known about the effects of oil palm polyculture farming on arthropod diversity. In this study, arthropods were sampled using pitfall traps at 120 sites in Peninsular Malaysia. We examined how arthropod biodiversity responded to different oil palm farming practices and local-scale vegetation structure characteristics. We found that the number of arthropod orders was significantly greater in polyculture than monoculture smallholdings. However, we did not detect a significant difference in arthropod order composition nor abundance between monoculture and polyculture practices. In situ habitat characteristics explained 16% of the variation in arthropod order richness, with key predictor variables including farming practice, height of oil palm stands, and number of immature palm. The findings of this study suggest that polyculture farming together with management for in situ habitat complexity may be a useful strategy in supporting biodiversity within in oil palm plantations