Interlayer Galleries Research Articles

Chitosan as a coating material in enhancing the controlled release behaviour of zinc hydroxide nitrate–sodium dodecylsulphate–bispyribac nanocomposite

The aim of this study is to modulate the controlled release properties of zinc hydroxide nitrate–sodium dodecylsulphate–bispyribac (ZHN–SDS–BP) nanocomposite, by coating the nanocomposite using chitosan. This study was conducted as part of an effort to reduce the environmental problems caused by the over-use of pesticides. The characterisation study shows that chitosan had been successfully coated onto the outer surface of the ZHN–SDS–BP (BP concentration of 0.05 M) without changing the types of ions intercalated in its interlayer gallery. The chitosan-coated nanocomposite, ZHN–SDS–BP–Chi also possesses a better thermal stability compared to the uncoated nanocomposite. Owing to the polycationic, hygroscopic nature, and gelation ability of chitosan, the chitosan coating was found to significantly prolong the release of bispyribac. The ZHN–SDS–BP–Chi showed a better performance in releasing pesticides, with prolonged release time ranging from 462 to 5349 min, compared to 74 to 4117 min for the uncoated nanocomposites. The release kinetic studies reveal that the release of bispyribac from the ZHN–SDS–BP–Chi is controlled by a pseudo-second-order kinetic model, thus signifying that the release mechanism is via dissolution and ion-exchange processes. The potential of chitosan in slowing the release of BP from ZHN–SDS–BP–Chi will hopefully contribute to minimise the risk of pollution resulting from the excessive use of pesticides.

Antibactericidal nanoclay-based biomaterial for sustained delivery of tetracycline hydrochloride

Nanoclay-based drug delivery vehicle has acquired immense recognition owing to its unique physico-chemical properties. In this study, tetracycline hydrochloride (TCH) drug was intercalated into the interlayer gallery of montmorillonite (Mt) clay by a cation exchange process. The intercalated nanocomposites were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, energy dispersive X-ray and thermogravimetric study. It was evident from the characterization that TCH drug was successfully intercalated into the interlayer gallery of Mt clay. These clay-based formulations exhibited antibacterial activity against both Gram-positive and Gram-negative bacteria on analyses via zone inhibition methods. An in-vitro drug release study was performed in phosphate buffer at physiological temperature and interestingly it exhibited sustained and controlled release of TCH from the nanocomposites, after an initial burst-out effect. Overall, this study showed that these nanocomposite materials have immense potential for use in controlled drug delivery strategies for antibacterial treatment.

Flexibly transparent luminescent organic-inorganic-polymer composite films: Intense full-color emissions at a single excitation wavelength

A versatile method utilizing organic-inorganic-polymer composite materials has been developed for the fabrication of both white-converting films and flexibly transparent full-color luminescent films. In this study, a single organic UV-harvester, salicylate (sal), was intercalated into the gallery of Eu3+-doped layered terbium hydroxide (LTbH:Eu), Tb3+-doped layered yttrium hydroxide (LYH:Tb), and layered yttrium hydroxide (LYH), to create three primary color emitting hybrids, sal-LTbH:Eu, sal-LYH:Tb, and sal-LYH. By adopting an identical organic sensitizer, its S0 → S1 (π, π*) transition was able to produce characteristically intense 5D0 → 7FJ Eu3+ red-emissions, as well as 5D4 → 7FJ green-emissions of Tb3+, through energy transfer to host matrices without a change in excitation wavelength. Despite a considerable energy difference between the 5D0 resonance energy level of Eu3+ and the lowest triplet state of salicylate, the energy transfer of Tb3+ to Eu3+ in the LTbH:Eu matrix resulted in the intense red-emission observed for Eu3+. In contrast, when the salicylate was included into the interlayer gallery of LYH (containing no activator ions), its typical blue-emission was found preserved at the same excitation wavelength. Moreover, these salicylate-intercalated hybrids, prepared by a facile aqueous solution route at room temperature, were well dispersed in water to form luminescent colloidal solutions. By mixing individual hybrid colloids at certain specific ratios, an intense white-light and full-color emission was successfully achieved at a low excitation energy (λ = 365 nm) using a commercial UV-lamp. Polyvinyl alcohol (PVA) was also employed to produce flexibly transparent luminescent composite films via simple casting of desired hybrid-dispersed solutions. Full-color generation and white-light converting behavior was demonstrated using the as-synthesized organic-inorganic-polymer composite films.

Synthesis of calcium‐layered double hydroxide based nanohybrid for controlled release of an anti‐inflammatory drug

AbstractThe study proposed an approach for synthesis‐Layered Double Hydroxide nanoparticles by the coprecipitation method in solution containing two divalent and trivalent metal salts, calcium, and aluminum. The synthesized calcium‐layered Double Hydroxide (CAL) used for intercalating an anti‐inflammatory drug with the purpose of obtaining controlling release rate, protecting of drug from decomposition and raising the poor aqueous solubility of drug. Mefenamic acid (ME) as anti inflammatory drug was intercalated into CAL from ion‐exchange route to preparation CAL/ME nanohybrids. An increase in the space of interlayer of the (002) plane from 8.06 Å in pristine CAL to 34.51 Å in the nanohybrid confirmed successful intercalation of ME anion into CAL framework, which was ordered in a bilayer fashion with the carboxylate functional groups in the interlayer gallery of CAL. The x‐ray diffraction and FTIR study indicated that the ME was successfully intercalated into interlayer space of CAL. The chemical composition of samples was evaluated by ICP‐OES and energy‐dispersive spectrum analysis. TG analysis confirmed that the thermal stability of intercalated ME in the form of nanohybrid was enhanced. dynamic light scattering and field emission scanning electron microscopy were determined the size of CAL particles. Finally, in vitro drug release experiments of nanohybrid at a PH of 4.8 and 7.4 showed sustained release profiles with ME anions as an anti‐inflammatory model drug.

Electrodeposited Zn-Al layered double hydroxide films for corrosion protection of aluminum alloys

This work provides a simple strategy to enhance the corrosion resistance of layered double hydroxide (Zn-Al LDH) films on AA2024 aluminum alloys by an electrodeposition method. Inhibitor anion vanadates are further intercalated into the interlayer galleries of LDHs through an ion-exchange process to improve their corrosion performance. Vanadates enhance the barrier property of the LDH films and are enriched in the corrosion sites to actively protect aluminum alloys. A literature survey shows that the electrodeposited LDH films exhibit comparable corrosion protection capacity to those prepared by the traditional hydrothermal method, although the former have the smallest thickness.

Synthesis and characterisation of zinc hydroxides nitrates–sodium dodecyl sulphate fluazinam nano hosts for release properties

A new nano host-fungicide, namely zinc hydroxide nitrate–sodium dodecyl sulphate–fluazinam (ZHN–SDS–FZ) was successfully synthesised using an ion exchange method. The intercalation of fluazinam (FZ) in the interlayer gallery of ZHN–SDS was confirmed by PXRD pattern with the basal spacing of 32.7 A. The FTIR confirmed that FZ exist in the interlayer gallery. The elemental analysis also supported the presence of FZ in the interlayer ZHN–SDS where the percentages of nitrogen, which contributed by FZ was 65.6%. Meanwhile, the percentages of Zn in the nano host-fungicides was estimated to be 11.5%. Furthermore, TGA/DTG pattern showed that the nano host-fungicide ZHN–SDS–FZ has better thermal stability compared to pure FZ. The intercalation of FZ leads to the change of morphology, surface area and also the porosity. The classification of porosity of ZHN–SDS is mesoporous, meanwhile ZHN–SDS–FZ is non-porous. The BET-BJH surface area shows that ZHN–SDS and ZHN–SDS–FZ is of Type IV and Type III respectively. The controlled release of FZ from the ZHN–SDS–FZ nano host showed that phosphate and carbonate solutions yield the higher percentages of release compared to chloride solutions. The controlled release of FZ was found to be governed by a pseudo-second order mechanism for all medium. In this research, FZ can act as a good guest anion to be intercalated in the interlayer ZHN–SDS to be further used in agricultural sector due to the slowest release of FZ in the phosphate, carbonate and chloride solutions as a release medium.

Strategy for Modifying Layered Perovskites toward Efficient Solar Light-Driven Photocatalysts for Removal of Chlorinated Pollutants

We have explored an efficient strategy to enhance the overall photocatalytic performances of layered perovskites by increasing the density of hydroxyl group by protonation. The experimental procedure consisted of the slow replacement of interlayer Rb+ cation of RbLaTa2O7 Dion-Jacobson (DJ) perovskite by H+ via acid treatment. Two layered perovskites synthesized by mild (1200 °C for 18 h) and harsh (950 and 1200 °C, for 36 h) annealing treatment routes were used as starting materials. The successful intercalation of proton into D-J interlayer galleries was confirmed by FTIR spectroscopy, thermal analyses, ion chromatography and XPS results. In addition, the ion-exchange route was effective to enlarge the specific surface area, thus enhancing the supply of photocharges able to participate in redox processes involved in the degradation of organic pollutants. HLaTa_01 protonated layered perovskite is reported as a efficient photocatalyst for photomineralization of trichloroethylene (TCE) to Cl− and CO2 under simulated solar light. The enhanced activity is attributed to combined beneficial roles played by the increased specific surface area and high density of hydroxyl groups, leading to an efficiency of TCE mineralization of 68% moles after 5 h of irradiation.

Synergetic light stabilizing effects of reducing agent and UV absorber co-intercalated layered double hydroxides for polypropylene

Light stabilizers are widely used in the plastic industry to extend the service life of plastics for outdoor use. Herein, a novel organic–inorganic hybrid light stabilizer was prepared by co-intercalating a reducing agent sorbic acid (SA) and an UV absorber 2-hydroxy-4-methoxy-benzophenone-5-sulphonic acid (UVA) into the interlayer galleries of MgAl layered double hydroxides (LDH) by a separate nucleation and aging steps method. The prepared SA–UVA–LDH was characterized by XRD, FT–IR, SEM, TG–DTA and UV–vis, and was added into the matrix of PP as light stabilizer to evaluate its stabilization efficiency. The results showed that SA–UVA–LDH was evenly distributed in PP, and can offer excellent UV–blocking effect for PP. The addition of SA–LDH, UVA–LDH and SA–UVA–LDH can enhance both the thermal and light stability of PP. It was found that the stabilizing mechanism of SA–LDH arising from the reducing ability of SA is different from the UV–blocking mechanism of UVA–LDH. SA–UVA–LDH/PP has better light stability than SA–LDH/PP and UVA–LDH/PP due to the existence of synergistic stabilizing effect between SA and UVA. Therefore, the prepared SA–UVA–LDH can be potentially used as novel hybrid light stabilizer for PP.

Mechanism of the graphene oxide formation: The role of water, “reversibility” of the oxidation, and mobility of the C–O bonds

Despite recent progress, the mechanism of the graphene oxide (GO) formation remains largely unknown. In this work, we report new findings, which add crucial details to the previously envisioned mechanism of the Hummers’ method reaction. The rate of the chemical reaction increases significantly with water content in the acid, and reaches the maximum in the acid concentration range 88%–92%. Graphite cannot be oxidized in the anhydrous sulfuric acid. We propose that the species, attacking carbon atoms, are not the Mn(VII) oxygen derivatives, as it is commonly believed, but water molecules. The withdraw of electrons from carbon atoms by Mn(VII) species, and the nucleophilic attack by water molecules occur simultaneously as a concerted process. The Mn(VII) species do not penetrate graphite interlayer galleries, but water molecules do.The formation of the covalent C–O bonds on the graphene plane is reversible, as long as the graphite sample remains intercalated with sulfuric acid. The as-formed bonds can be easily cleaved by the laser irradiation, converting GO back to stage-1 GIC in small local areas of the graphite flake. We interpret this “reversibility” as the “migration” of the newly formed C–O bonds on the graphene plane. The pattern of the C–O bond migration is largely controlled by the local graphite structure.The discovered phenomena and proposed reaction mechanism provide rationale for a range of the well-known but yet poorly understood experimental observations in the graphene chemistry. Among them is the existence of the oxidized and graphenic domains in the GO structure. The new findings and conclusions create the holistic view on the driving forces of the transformations that occur with graphite in the oxidative acidic media.

Structure Regulation of Bentonite-Alginate Nanocomposites for Controlled Release of Imidacloprid.

To reveal the structure and release properties of bentonite-alginate nanocomposites, bentonite of different amounts was incorporated into alginate by the sol–gel route. The structure of the composites was characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and thermogravimetric analysis and related to the swelling property of the matrix and the release of imidacloprid. Bentonite was subject to exfoliation into nanoplatelets and combined into the polymeric network within alginate hydrogel, exhibiting profound effects on the structure features and release properties of the composites. Bentonite was of good compatibility with alginate due to the hydrogen bonding and the electrostatic attraction between them. The polymer chains were found to intercalate into the interlayer gallery of the clay. The high specific area of the nanoplatelets of bentonite benefited the intimate contact with alginate and reduced the permeability of the composites. However, in the composites with clay content of more than 10%, the polymer was insufficient to accommodate the silicate sheets completely. The aggregation of the platelets destroyed the structure integrity of the composites, facilitating the diffusion of the pesticide. The release of imidacloprid was greatly retarded by incorporating into bentonite-alginate composites and dominated by Fickian diffusion depending on the permeability of the matrix. The time taken for 50% of the active ingredient to be released, T50, first increased and then decreased with increasing clay content in the composites, reaching a maximum around a weight percentage of 10%, at which the T50 value for imidacloprid release was about 2.5 times that for the release from pure alginate formulation.

The structural versus textural control on the methane sorption capacity of clay minerals

In the natural, high-pressure environments of sediments and sedimentary rocks, clay minerals, along with organic matter, contribute to a large portion of the available surface area and microporosity in which methane (CH4) can be adsorbed. However, most of the questions concerning the location of adsorption sites, e.g. interlayer accessibility for CH4, remain unknown. Here, we have separately investigated the textural and structural control on CH4 high-pressure adsorption on pure clay minerals by combining high- and low-pressure gas adsorption techniques, transmission electron microscopy, and thermogravimetric and X-ray diffraction analyses on various cationic forms of montmorillonite, beidellite, and two illites, with different contents of adsorbed water. The results show that CH4 adsorption capacity is controlled by N2-accesible micropore volume. CH4 adsorption sites are located mainly outside of the interlayer galleries unless they are open wide enough (e.g. pillared by organic cations or incompletely dried divalent cations). However, the structure-independent factors like the crystallite planar dimensions and the way that they assemble are the main control on CH4 adsorption capacity. This might be the reason for the inconsistencies in CH4 adsorption reported for clay minerals in the literature. CO2 adsorption measurements, assumed to provide a good proxy for the estimation of CH4 adsorption capacity in natural mudrocks, may overestimate the CH4 adsorption potential in geomaterials containing a significant amount of exchangeable divalent cations due to higher penetrability of CO2 than CH4 in the interlayers of expandable clay minerals.

Thermodynamics and kinetics of pretilachlor adsorption: Implication to controlled release from organobentonites

To get a further insight into the mechanism of controlled release from organobentonites, thermodynamics and kinetics of pretilachlor adsorption on organobentonites modified with dodecyltrimethyl ammonium chloride (DTMA) was conducted. The structural effects of organobentonites on the interaction with pretilachlor and the diffusion of the herbicide in interlayer space were investigated and related to the sustained release of pretilachlor from organobentonites. The adsorption of pretilachlor was a spontaneous process (ΔG < 0) dominated by hydrophobic interaction with an unfavorable enthalpy (ΔH > 0) and favorable entropy change (ΔS > 0). The entropy change dropped with increasing surfactant loading of organobentonites, corresponding to a decrease in the degree of freedom of pretilachlor molecules due to the enhanced structure order of the surfactant in the interlayer gallery. However, the increase in surfactant loading generally resulted in an enhancement of pretilachlor adsorption due to the reduction of enthalpy change. As compared to the pseudo-first-order model, the pseudo-second-order model fitted better to the kinetics of pretilachlor adsorption on organobentonites, of which the rate constant k2 decreased and level off with increasing surfactant loading, exhibiting a similar trend to the entropy change for pretilachlor adsorption. The release of pretilachlor from organobentonites was predominated by Fickian diffusion, which could be understood from adsorption thermodynamics and kinetics. The time taken for 50% of active ingredient to be released, T50, from organobentonites with DTMA loading level ranged from 40 to 150% of the cation exchange capacity of the bentonite was 6–10.6 times that for the control formulation and exhibited a good linear relationship with the relative value of the adsorption equilibrium constant Ka to the rate constant k2 from pseudo-second-order model.

Synthesis and micro-mechanistic studies of histidine modified montmorillonite for lead(II) and copper(II) adsorption from wastewater

A novel nanocomposite of sodium montmorillonite with L-Histidine (His-Mt), was prepared to remove Pb(II) and Cu(II) from aqueous media. The resulting nanocomposites were characterized by XRD, FT-IR, BET, SEM, TG/DTG, XPS techniques. All characterizations confirmed the anchoring of L-Histidine to Na-Mt, and the packing sequence of His in the interlayer gallery may form a monolayer structure. The His salt obtained a skewed orientation compared to the silicate surface. The single/ co-adsorption of Cu(II) and Pb(II) by pure and modified i.e. Na-Mt and His-Mt were carried out by batch adsorption experiments. The maximum adsorption capacity (qmax) of Pb(II) and Cu(II) by Na-Mt and modified His-Mt was 89.08mg/g, 23.93mg/g, and 107.73mg/g, 30.72mg/g, correspondingly. The pseudo-second-order model (kinetic model) and Langmuir model (isotherm model) well-matched with the adsorption process. The data analysis showed it was an endothermic, favorable and spontaneous process, Cu(II) and Pb(II) showed competitive adsorption in the co-adsorption system. Na-Mt adsorbed M(II) ions by ion exchange mechanism, while M(II) formed complexes with histidine and were adsorbed in the interlayer region or the surface of His-Mt.

Facile In Situ Hydrothermal Synthesis of Layered Zirconium Phenylphosphonate Molecular Sieve Membranes with Optimized Microstructure and Superb H2/CO2 Selectivity.

Layered molecular sieve membranes containing uniform interlayer galleries have offered unprecedented opportunities to reach a performance far beyond the Robeson upper bound line. In this study, we took the initiative to prepare layered zirconium phenylphosphonate (ZrPP) molecular sieve membranes with optimized microstructure on tetragonal zirconia (t-ZrO2) buffer layer-modified porous α-Al2O3 substrates by facile in situ hydrothermal growth. Relying on the 3.2 Å-sized gallery height and preferential CO2 adsorption behavior, prepared ZrPP membranes showed exceptional H2/CO2 selectivity (>100) as well as considerable H2 permeability. Furthermore, extraordinary thermal, mechanical, and chemical stability of ZrPP membranes made them potentially attractive for long-term operations under harsh conditions.

Building vertically-structured, high-performance electrodes by interlayer-confined reactions in accordion-like, chemically expanded graphite

Graphene has attracted major interests as electrode materials for energy storage applications. However, the major limitation of using blade- or spin-coated graphene films for fabricating electrode is that the basal plane of the flat-lying graphene is orthogonal to the direction of charge transport, causing sluggish charge transfer kinetics for the coated graphene film. Here we propose a general, scalable strategy to prepare vertically-structured hybrid electrodes using accordion-like, chemically expanded graphite (CEG). The coated CEG rods possess two-dimensional (2D) interlayer galleries that are vertically aligned with respect to the substrate because of their large length-diameter ratio, which facilitates high-efficiency ion transport. Due to its excellent wettability and high electrochemical surface areas, these interlayer galleries allow a high loading of redox-active (RA) materials, including metal (Pt), metal hydroxide (Ni(OH)2, Fe2O3 and MnO2) or metal dichalcogenide (MoS2). As an example, Ni(OH)2-infiltrated CEG shows excellent rate-performance and long-term cycling stability when used as electrochemical electrodes in lithium-ion batteries and supercapacitors.

Intercalation of laminar Cu-Al LDHs with molecular TCPP(M) (M = Zn, Co, Ni, and Fe) towards high-performance CO2 hydrogenation catalysts.

A confined space is broadly applied to enhance the dispersion and limit the aggregation of catalytically active sites, especially at high temperatures. In this work, we provided an efficient approach to immobilize transition metal ions (e.g., Zn2+, Co2+, Ni2+, and Fe2+) into the confined space of laminar Cu-Al layered double hydroxides (LDHs) using a range of molecular metalloporphyrins (viz., TCPP(M)) as shuttles. The deprotonated TCPP(M) not only provides nitrogen-based coordination sites to anchor a series of transition metal ions, but also intercalates and diffuses facilely into the interlayer gallery of LDHs by ion exchange. The obtained TCPP(M)@Cu-Al LDHs were then used as solid precursors for the fabrication of a series of heterogeneous catalysts for CO2 hydrogenation via high-temperature calcination. Two restriction forces contributed to the enhanced dispersion of the active species over the catalyst surface structures. Remarkably, the transition metals positioned within the confined space of LDHs significantly affected the catalytic performance of CO2 hydrogenation. Mainly CO, methanol, and methane were found as the C1 products, and their selectivities are highly dependent on the reaction intermediates, as suggested by the in situ DRIFTS study. Moreover, the designed catalysts fabricated via molecular TCPP(M) intercalation exhibited much better performance than the conventional catalysts derived from surface-supported CA-LDHs, due to their better metal dispersion and smaller particle size.

Effect of organomodifier on the electrical property of a smectite clay Hectorite

Dielectric properties of organo-modified hectorite clay by different modifier with varying chain length have been investigated. Organomodification process has been established by the x-ray diffraction pattern. Interlayer water molecule and interlayer gallery cations affect the conductivity of hectorite clay. NH4CL modified and unmodified clay shows a similar impedance spectra pattern at a higher temperature. Whereas for dodecyl amine (DDA) modified clay impedance spectra indicates a dependence of ion conduction upon its tail constituents.

Influence of the presence of cations on the water and salt dynamics inside layered graphene oxide (GO) membranes

Although over the past few years, graphene oxide (GO) has emerged as a promising membrane material, the applicability of layered GO membranes in water purification/seawater desalination is still a challenging issue because of the undesirable swelling of GO laminates in the aqueous environment. One of the ways to tune the interlayer spacing and to arrest the undesirable swelling of layered GO membranes in the aqueous environment is to intercalate the interlayer spacing of the GO laminates with cations. Although the cation intercalation imparts stabilization to GO laminates in the aqueous environment, their effect on the performance of the membrane is yet to be addressed in detail. In the present study we have investigated the effect of cation intercalation on the performance of layered GO membranes using molecular dynamics simulation. For the same interlayer spacing, the cation intercalated layered GO membranes have a higher water flux as compared to the corresponding pristine layered GO membranes. In the presence of the cations, the water molecules inside the interlayer gallery get more compactly packed. The presence of the cations also increases the stability of the hydrogen bond network among the water molecules inside the membrane. This can be attributed to slow water reorientation dynamics inside the interlayer gallery in the presence of the cations. The synergistic effect of all these changes is that the water permeability through the cation intercalated layered GO membranes is higher as compared to that through the corresponding pristine layered GO membranes. On the other hand, the intercalation of the cations (K+, Mg2+) leads to higher rejection of Na+ ions whereas the rejection of Cl- ions slightly decreases.

Preparation of CeO2-decorated organic-pillared hydrotalcites for the UV resistance of polymer

A series of 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid (BP-4) pillared hydrotalcites (CeO2-BP-LDH) decorated by CeO2 nanoparticles were successfully prepared by calcination-reconstruction, in which the effect of the temperature during the ternary ZnAlCe-LDH precursorcalcinationon the anti-photoaging ability was studied. The microstructure, bonding state, surface properties and UV-absorption properties of the CeO2-BP-LDH materials were investigated by XRD, FT-IR, SEM/EDS, TEM/HRTEM, XPS, BET/BJH, UV–vis-DRS and TG-DTG, suggesting that CeO2 was successfully grafted onto the surface of the LDH host layers, and BP-4 anions were intercalated into the interlayer galleries during the calcination-reconstruction process. For the CeO2-BP-LDH materials, the microstructure, such as the interlayer gallery and specific area (SBET) was related closely with the temperature of calcining the ZnAlCe-LDH precursor. Moderate calcination temperature could enlarge the interlayer gallery (d003 value), which resulted in more amount of interlayer BP-4 anions and higher specific area (SBET) with more UV-photoadsorption site to effectively improve the anti-photoaging ability of PP polymer. Especially, the CeO2-BP-LDH400 obtained at 400 °C had the largest interlayer gallery and highest SBET, which indicated the strongest UV-photoadsorption ability and optimal anti-photoaging ability for PP polymer due to the synergy of the LDH host-layer and supramolecular BP-4-guest anion as well as CeO2 nature property.

Surfactant-assisted imidacloprid intercalation of layered zinc hydroxide nitrate: synthesis, characterisation and controlled release formulation

A neutrally charged insecticide, imidacloprid (IC), has been intercalated into zinc hydroxide nitrate (ZHN) with the assistance of sodium dodecylsulphate (SDS). The presence of SDS assists the intercalation of IC by forming a hydrophobic region in the interlayer gallery of ZHN. The intercalated compound, ZHN–SDS–IC, was characterised using powder X-ray diffraction (PXRD), thermogravimetric analysis, Fourier transform infrared spectroscopy, elemental analysis, field emission scanning electron microscopy, and gas sorption analysis. The PXRD studies demonstrated intercalation peaks at lower 2θ, which confirmed the intercalation of IC and SDS in the interlayer gallery of ZHN. The release and kinetic studies of ZHN–SDS–IC reveals that the IC were successfully released in controlled manner (with release time up to 1478 min), and were governed by pseudo second order kinetic model. The ZHN–SDS–IC synthesised is hopefully beneficial in overcoming the consequences of excessive usage of insecticide in paddy cultivation.