Starch-derived carbon quantum dots: Unveiling structural insights and photocatalytic potential as a bio-sourced metal-free semiconductor.

The optical appeal and sustainability of carbon quantum dots (CQDs) have led to these nanoparticles swiftly gaining attention and emerging as a new, multifunctional class of nanomaterials. This work centers on the hydrothermal preparation of CQDs utilizing starch, an abundant and renewable biopolymer, as the precursor. Extensive characterization via spectroscopy and microscopy techniques revealed that the starch-derived CQDs exhibit a spherical nanoscale morphology averaging a âˆ¼ 4 nm diameter, demonstrating a red-orange photoluminescence emission. Diffuse reflectance spectroscopic analysis verified their semiconductor behavior, with an estimated direct band gap of 4.1 eV comparable to conventional semiconductors. The prepared CQDs demonstrated considerable promise as metal-free, semiconductor photocatalysts for degrading aqueous dye pollutants under UV irradiation. High photodegradation efficiencies of 45.11 %, 62.94 %, and 91.21 % were achieved for Acid Blue 21, Reactive Blue 94, and Reactive TB 133 dyes, respectively. Systematic investigations of critical process parameters like pH, CQDs dosage, dye concentration, and contact time provided vital insights into the photocatalytic mechanism. The bio-sourced CQD nanomaterials offer a sustainable pathway for effective environmental remediation.

Synergistic potential in spinel ferrite MFe2O4 (M = Co, Ni) nanoparticles-mediated graphene oxide: Structural aspects, photocatalytic, and kinetic studies.

The existence of artificial dyes in water is a significant environmental concern, as it can lead to poor water quality. Photodegradation is becoming an increasingly popular method for treating water contaminated with dyes. In this study, the photodegradation of Reactive Red 66 and Reactive Red 120 dyes, as well as textile wastewater, was investigated under UV and visible light irradiation. To enhance the photoresponse of the MFe2O4 (M = Co, Ni) nanoparticles, modifications were made by incorporating graphene oxide. The MFe2O4 nanoparticles and MFe2O4/GO nanocomposite photocatalysts were subjected to several characterization techniques, including FT-IR, Raman spectroscopy, XRD, DRS, zeta potential, VSM, TGA, DSC, BET, SEM, and EDAX analysis. Experiments were conducted to optimize several key parameters involved in the photodegradation process, including pH, photocatalyst dosage, initial dye concentration, and irradiation time. The removal efficiency of Reactive Red 66 and Reactive Red 120 dyes using CoFe2O4 nanoparticles was found to be 86.97 and 82.63%, respectively. Also, the removal percentage of these dyes using CoFe2O4/GO nanocomposite photocatalyst was 95.57 and 90.9% for Reactive Red 66 and Reactive Red 120, respectively. Experiments found that NiFe2O4 nanoparticles removed 90.92% of Reactive Red 66 dye and 84.7% of Reactive Red 120 dye. The NiFe2O4/GO nanocomposite photocatalyst showed even higher removal efficiencies, degrading 97.96% of Reactive Red 66 and 93.44% of Reactive Red 120. After three days of exposure to visible light irradiation, the removal percentage of Reactive Red 66 using MFe2O4 and MFe2O4/GO nanocomposite was investigated.

Hydrogen bond-mediated self-assembly of Tin (II) oxide wrapped with Chitosan/[BzPy]Cl network: An effective bionanocomposite for textile wastewater remediation.

A novel and efficient bionanocomposite was synthesized by incorporating SnO into chitosan (Ch) and a room-temperature ionic liquid (RTIL). The bionanocomposite was synthesized in benzoyl pyridinium chloride [BzPy]Cl to maintain the unique properties of SnO, chitosan, and the ionic liquid. Adsorption and photodegradation processes were applied to evaluate the bionanocomposite for removing azo and anthraquinone dyes and textile wastewater. SnO/[BzPy]Cl and SnO/[BzPy]Cl/Ch samples were prepared and characterized using various techniques, including FT-IR, SEM, XRD, EDAX, XPS, DSC, TGA, nitrogen adsorption/desorption isotherm, and DRS analysis. SEM analysis revealed a hierarchical roughened rose flower-like morphology for the biocomposite. The band gap energies of SnO/[BzPy]Cl and SnO/[BzPy]Cl/chitosan were found to be 3.9 and 3.3 eV, respectively, indicating a reduction in the band gap energy with the introduction of [BzPy]Cl and chitosan. SnO/[BzPy]Cl/Ch showed high removal rates (92-95 %) for Fast Red, Blue 15, Red 120, Blue 94, Yellow 160, and Acid Orange 7 dyes. The adsorption kinetics followed a pseudo-second-order model. In addition, the effect of different photodegradation parameters such as solution pH, dye concentrations, contact time, and amount of photocatalyst, was studied. Given the optimal results obtained in removing azo and anthraquinone dyes, the SnO/[BzPy]Cl/Ch nanocomposite was used as an efficient nanocomposite for removing dyes from textile wastewater. The highest removal efficiency was found to be 95.8 %, obtained under ultraviolet and visible light. Furthermore, BOD and COD reduction analysis showed significant reductions, indicating the excellent performance of the photocatalyst.

Intercalated chitosan-ionic liquid ionogel in SnO nanoplate: band gap narrow and adsorption-photodegradation process.

Ionogels are a category of hybrid material containing ionic liquid stabilized by polymeric network. These composites have some applications in solid-state, energy storage devices and environmental studies. In this research, chitosan (CS), ethyl pyridinium iodide ionic liquid (IL), and ionogel (IG) consisting of chitosan and ionic liquid were used in the preparation of a SnO nanoplate (SnO-IL, SnO-CS and SnO-IG). For the preparation of the ethyl pyridinium iodide, a mixture of pyridine and iodoethane (1: 2 molar ratio) was refluxed for 24 hours. The ionogel was formed using ethyl pyridinium iodide ionic liquid in chitosan that was dissolved in acetic acid (1 % v/v). By increasing NH3∙H2O, the pH of the ionogel reached 7-8. Then, the resultant IG was mixed with SnO in an ultrasonic bath for 1 h. The microstructure of the ionogel was involved as assembled unit via π-π, electrostatic and hydrogen bonding interactions to be three-dimensional networks. The intercalated ionic liquid and chitosan influenced the stability of the SnO nanoplates and improved band gap values. When chitosan was contained as the interlayer space of the SnO nanostructure, the resulting biocomposite formed a well-ordered flower-like SnO structure. These hybrid material structures were characterized by FT-IR, XRD, SEM, TGA, DSC, BET, and DRS techniques. The changes in the band gap values for photocatalysis applications were investigated. In the case of SnO, SnO-IL, SnO-CS, and SnO-IG, the band gap energy was 3.9, 3.6, 3.2, and 2.8 eV, respectively. The dye removal efficiency of SnO-IG was 98.5, 98.8, 97.9, and 98.4 % via the second-order kinetic model for Reactive Red 141, Reactive Red 195, Reactive Red 198, and Reactive Yellow 18, respectively. The maximum adsorption capacity of SnO-IG was 540.5, 584.7, 1501.5, and 1100.1 mg/g for Red 141, Red 195, Red 198, and Yellow 18 dyes, respectively. Also, an acceptable result (96.47 % dye removal) was obtained with the prepared SnO-IG biocomposite for dye removal from textile wastewater.

Design, synthesis, and characterization of a novel Zn(II)-2-phenyl benzimidazole framework for the removal of organic dyes.

A novel Zn (II) organic framework comprising 2-phenyl benzimidazole (ZPBIF-1) was synthesized by using a solvothermal method. The characterization of the synthesized MOF was performed utilizing XRD, SEM, FT-IR, 1H-NMR, 13C-NMR, MS, XPS, TG/DTA, and N2 sorption analysis. ZPBIF-1 was successfully utilized to remove Acid red 88, Basic Violet 14, Basic Blue 54, and Congo red dyes in aqueous solutions. In this study, some parameters, including adsorbent dosage, initial dye concentration, contact time, temperature, and pH, were examined. To evaluate the experimental data, Freundlich, Langmuir, Temkin, and Dubinin-Radushkevich isotherm models were used. In this case, Langmuir is the most suitable model. Several kinetic models, including First-order, pseudo-first-order, second-order, and Pseudo-second-order kinetic models, Elovich's, and Weber's intraparticle diffusion models, were utilized to comprehend the detailed adsorption process. According to the pseudo-second-order kinetic model, dye sorption kinetics is best described. In addition, thermodynamic parameters like enthalpy (ΔH°), Gibbs free energy (ΔG°), and entropy (ΔS°) were also achieved and analyzed. The experimental studies thus suggest that Zn (II) metal-organic framework based on 2-phenyl benzimidazole could be a promising candidate for eliminating dyes from aqueous solution. Hence, the experimental studies suggest that a Zn (II) metal-organic framework based on 2-phenylbenzimidazole could be a promising candidate for eliminating dyes from aqueous solution. The maximum adsorption capacity of ZPBIF-1 was 1666.66, 1250, 1000, and 1250 mg/g for Acid red 88, Basic violet 14, Basic blue 54, and Congo red dyes, respectively. Furthermore, this method was used to remove contaminant dyes from textile wastewater, and an acceptable result was obtained.

Desalination of saline water via forward osmosis using magnetic nanoparticles covalently functionalized with citrate ions as osmotic agent.

Forward osmosis is an emerging membrane technology in water desalination. In this study, desalination of saline water via forward osmosis was investigated using a new magnetic osmotic agent. For this purpose, Fe3O4 nanoparticles covalently functionalised with tri-sodium citrate was synthesised and characterised. The structural examinations revealed that the sodium citrate had been immobilised onto the magnetic nanoparticles. The highest water flux was obtained 17.1 L M-2 h (LMH) per 80 g L-1 osmotic agent solution against deionised water, while the ratio of salt flux to water flux was very low (0.088 g L-1). The osmotic solution was evaluated for saline water desalination using different concentrations of sodium chloride (NaCl) as feed solutions. The average water fluxes of 6.2, 4.5, and 2.7 LMH was obtained for 0.1, 0.2, and 0.5 M salt solutions, respectively. The magnetic osmotic agent was separated by a magnet and re-used for several times without considerable decrease in the water flux.

New anticancer Pd and Pt complexes of tertamyl dithiocarbamate and DACH ligands against HT29 and Panc1 cell lines.

To investigate the reduction of side effects of commercial antitumor drugs such as cisplatin, two new platinum and palladium complexes with a formula of [M(DACH)(tertamyl.dtc)]NO3 were synthesized (DACH is 1R, 2R-diaminocyclohexane, tertamyl-dtc is tertpentyl dithiocarbamate, and M is palladium or platin ionic metals) and characterized by spectroscopic methods. The in vitro cytotoxicity of these compounds against HT29 and Panc1 cell lines showed that the IC50 values against Panc1 cell line of [Pt(DACH)(tertamyl.dtc)]NO3 and [Pd(DACH)(tertamyl.dtc)]NO3 were 263.1 and 198.7 µM, and also against HT29 cell line were 241.9 and 258.2 µM, respectively. They were similar to the value obtained for oxaliplatin and lower than cisplatin value. Thermal stability and circular dichroism results demonstrated that both metal complexes could bind to DNA via electrostatic bonds. Due to electrostatic interaction, the configuration of B-DNA to C-DNA changed, though the possibility of groove interaction may be strengthened. Furthermore, molecular docking simulation showed higher negative docking energy for [Pd(DACH)(tertamyl.dtc)]NO3 complex with a higher tendency for DNA interaction. In vitro cytotoxicity of two new Pt and Pd compounds have been studied against two cell lines (HT29 and Panc 1), which are almost equal to the value obtained for oxaliplatin and they are lower than cisplatin value. Thermal stability studies and CD results demonstrated that both complexes bind to DNA via electrostatic bonds. Further, molecular docking showed higher negative docking energy for [Pd(DACH)(tertamyl.dtc)]NO3 complex with a higher tendency for interaction.Communicated by Ramaswamy H. Sarma.

Cross-linked chitosan into graphene oxide-iron(III) oxide hydroxide as nano-biosorbent for Pd(II) and Cd(II) removal.

In this study, chitosan cross-linked into graphene oxide/iron(III) oxide hydroxide nanocomposites. For this purpose, to a mixture of graphene oxide in deionized water was added to iron(II) sulfide and hydrogen peroxide solution. The pH was then adjusted. Then, chitosan dissolved in acetic acid was added. This compound applied as nano-biosorbent for the removal of Pd(II) and Cd(II) ions from aqueous solution. Nanocomposites were characterized by FT-IR, XRD, SEM, and EDX analysis. The effects of valid parameters such as pH (2-9), sorbent mass (0.01-0.1 g), temperature (25-60 °C), and contact time (20-50 min) were investigated in adsorption of Pd(II) and Cd(II) ions. The results showed that oxygen-containing functional groups on the surface of graphene oxide, iron(III) oxide hydroxide nanoparticles, and the abundant amino and hydroxyl functional groups of chitosan chain were shown excellent potential for Pd(II) and Cd(II) adsorption. The removal percentage of Pd(II) and Cd(II) were 84 and 95%, respectively. The Freundlich and Langmuir adsorption isotherms were investigated for the description of adsorption onto nanocomposites. However, the Freundlich model showed a higher correlation coefficient (R2) than Langmuir isotherm. The pseudo-second-order equation was the best fitted kinetic model for this process.

Some new anticancer platinum complexes of dithiocarbamate derivatives against human colorectal and pancreatic cell lines.

Cisplatin, carboplatin and oxaliplatin and their analogs are effective anticancer agents, but their clinical using is limited by some serious side effects. S,S donor ligands such as dithiocarbamates can be used to reduce some side effects. In this study, some novel water soluble complexes with formula of [Pt(bpy)(R.dtc)]NO3, where bpy is bipyridine and R.dtc is amyl-, isopentyl- or tertamyl-dtc (n-pentyl-, 3-metyl-butyl- and 2-methylbutan-dithiocarbamate, respectively) have been synthesized and characterized by elemental analysis, conductivity measurements and chemical analysis. The cytotoxic activities of synthesized complexes were investigated against human adenocarcinoma colorectal cell line (HT29) and human pancreatic cell line (Panc1), and compared with cisplatin and oxaliplatin, which display more anticancer activity for [Pt(bpy)(isopentyl.dtc)]NO3. The experimental fluorescence and circular dichroism results illustrated partially groove binding of [Pt(bpy)(amyl.dtc)]NO3 and [Pt(bpy)isopentyl.dtc)]NO3 on DNA, while [Pt(bpy)(tertamyl.dtc)]NO3 complex, can bind to DNA via intercalation. Finally, molecular docking simulation data of DNA interaction with three synthesized complexes showed [Pt(bpy)(amyl.dtc)]NO3 complex has the highest tendency and negative docking energy in structural change of DNA.Communicated by Ramaswamy H. Sarma.

Preparation of magnetic graphene oxide-ferrite nanocomposites for oxidative decomposition of Remazol Black B.

A solvothermal synthesis method was used to prepare graphene oxide (GO) supported ferrite (MFe2O4, M=Fe, Co and Ni) nanocomposites. Subsequently, the application of MFe2O4 nanocomposites as photocatalyst for Remazol Black B (RBB) removal was investigated. The nanocomposites were characterized by X-ray powder diffraction (XRD), Fourier transform infrared spectra (FT-IR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and vibrating sample magnetometer. It was shown that dispersed MFe2O4 microspheres with uniform size (20-30nm) were homogeneously deposited on GO nanosheets. The vibrating sample magnetometer (VSM) studies show superparamagnetic behavior of all nanocomposites in the range of 41-43 emu/g at room temperature. In general, the obtained nanocomposites are effective photocatalyst for the removal of dye pollutant. The batch adsorption experiments showed that the adsorption of the RBB is considerably dependent on pH of milieu, amount of nanocomposite, and contact time. Under the same operational conditions, the optimal parameters for the prepared GO/MFe2O4 nanocomposites are: dye dosage=10ppm, contact time=60min, photocatalyst mass=5mg, and pH=3. The adsorption kinetics was investigated to show that it was well-described by pseudo-first order model. Finally, it can be concluded that the GO/MFe2O4 nanocomposites are promising nano-photocatalyst, which can be used for application in dye removal from the wastewater.

Preparation of graphene oxide/chitosan/FeOOH nanocomposite for the removal of Pb(II) from aqueous solution.

In the present study, a graphene oxide/chitosan/FeOOH (GO/Ch/FeOOH) nanostructured composite was prepared and used as an adsorbent for the removal of Pb(II) ions from aqueous solution. The nanocomposite was characterized by FT-IR, XRD, and SEM techniques. Several important parameters influencing the adsorption of Pb(II) ions such as pH (3-7), temperature (25-80 °C), shaking speed (150-800 rpm), contact time (10-70 min), and sorbent mass (10-100 mg) were studied. The results showed that, benefiting from the surface property of graphene oxide, the abundant amino and hydroxyl functional groups of chitosan, the adsorbent provides adequate and versatile adsorption for the Pb(II) ions under investigation. The batch adsorption experiments showed that the adsorption of the Pb(II) is considerably dependent on pH of milieu, amount of adsorbent, and contact time. The Freundlich and Langmuir adsorption models were used for the mathematical description of adsorption equilibrium and isotherm constants. Both models were applicable for the description of Pb(II) adsorption isotherm in the concentration range studied. However, Langmuir model showed higher correlation coefficient (R(2)) than Freundlich model. The study suggests that the GO/Ch/FeOOH is a promising nano adsorbent for the removal of Pb(II) ions from aqueous solution.

Removal of Acid Orange 7 from aqueous solution using magnetic graphene/chitosan: a promising nano-adsorbent.

Magnetic graphene/chitosan (MGCh) nanocomposite was fabricated through a facile chemical route and its application as a new adsorbent for Acid Orange 7 (AO7) removal was also investigated. After synthesis, the full characterization with various techniques (FTIR, XRD, VSM, and SEM) was achieved revealing many possible interactions/forces of dye-composite system. The results showed that, benefiting from the surface property of graphene oxide, the abundant amino and hydroxyl functional groups of chitosan, and from the magnetic property of Fe3O4, the adsorbent possesses quite a good and versatile adsorption capacity to the dye under investigation, and can be easily and rapidly extracted from water by magnetic attraction. The maximum absorption capacity was reached at initial pH 3 and 120min contact time. The batch adsorption experiments showed that the adsorption of the AO7 is considerably dependent on pH of milieu, amount of adsorbent, and contact time. The adsorption kinetics and isotherms were investigated to indicate that the kinetic and equilibrium adsorption were well-described by pseudo-first order kinetic and Langmuir isotherm model, respectively. The adsorption behavior suggested that the adsorbent surface was homogeneous in nature. The study suggests that the MGCh is a promising nano adsorbent for removal of anionic azo dyes from aqueous solution.

Suitable chemical methods for preparation of graphene oxide, graphene and surface functionalized graphene nanosheets.

This article presents the suitable chemical method for preparation of graphene oxide nanosheets. In order to examine the effects of HNO3/H2SO4 ratio on interlayer spacing and its comparison, the oxidation of graphite with HNO3 and H2SO4 in 1:2 and 1:3 volume ratios was done. Based on the reaction time and interlayer spacing, it was found that the optimum results were obtained when reaction was carried out with HNO3/H2SO4 in 1:3 volume ratio (using modified Staudenmaier method) for 4 days. Results showed that the modified Staudenmaier method improved efficiency exfoliation in oxidation process. Also, the chemical reduction of graphene oxide, which obtained using the modified Staudenmaier method, with hydroquinone and hydrazine hydrate was studied. The results indicate that use of hydrazine hydrate as the reducing agent was more beneficial than the hydroquinone. In continue, we describe the preparation of surface functionalized graphene nanosheets with octadecylamine. The products were characterized by Fourier transform infrared (FT-IR), Raman spectroscopy, X-ray diffraction (XRD), Atomic force microscopy (AFM), Field emission-scanning electron microscopy (FE-SEM) and X-ray photoelectron spectroscopy (XPS).

Effects of extractives on some properties of bagasse/high density polypropylene composite.

In this study, the effects of two variable parameters, namely the extractives and filler loading level, on the physical properties of composites were examined. Composites based on high density polyethylene (HDPE), bagasse flour (BF) as filler were made by injection molding. In order to increase the interphase adhesion, maleic anhydride grafted polyethylene (MAPE) was added as a coupling agent to all the composites studied. Three different solvents, ethanol-benzene, 1% NaOH and hot-water, were used to remove extractives. Physical properties, namely, water absorption (WA) and thickness swelling (TS) were investigated for a long period. At same filler loading, composites made with extracted bagasse had higher WA and TS values. In addition, the TS of samples showed a similar pattern to the water uptake data. The difference in WA between extracted and unextracted composites is due to blocking of -OH groups by extractives. The results also showed that as the BF content was increased, significant increase in WA and TS occurred. Statistical analysis confirmed that the effects of both variables and their interactions on the WA and TS properties were significant at 1% confidence level.

Preparation and characterization of some graphene based nanocomposite materials.

In this study, graphene based sheets such as graphene oxide (GO) and graphene (G) were produced via a facile preparation route involving graphite oxidation, ultrasonic exfoliation and chemical reduction. Also, this paper reports simple approaches for deposition of manganese dioxide, ferric hydroxide and cobalt nanoparticles onto the surface of the graphene based sheets. Chemical deposition method of metal salt with graphene based sheets was performed to prepare nanocomposites. The structural, surface and characteristics of the GO, G and their nanocomposites were investigated by Fourier transform infrared spectroscopy, Raman spectroscopy, powder X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, atomic force microscopy and X-ray photoelectron spectroscopy. The results demonstrated that interaction between GO as matrix and metal nanoparticles were via hydroxyl, carbonyl and/or carboxylate groups. The metal nanoparticles were homogeneously distributed on the matrix of composite.

Wood plastic composite using graphene nanoplatelets.

This article presents the preparation and characterization of wood flour/polypropylene (PP) composites filled with graphene nanoplatelets (GNPs). The effects of GNPs, as reinforcing agent, on the mechanical and physical properties were also investigated. In order to increase the interphase adhesion, maleic anhydride grafted polypropylene (MAPP) was added as a coupling agent to all the composites studied. The morphology of the specimens was characterized using scanning electron microscopy (SEM) technique. The results of strength measurements indicated that when 0.8 wt.% GNPs were added, tensile and flexural properties reached their maximum values. At high levels of GNPs loading (3-5 wt.%), increased population of GNPs leads to agglomeration and stress transfer gets blocked. The addition of GNPs filler moderately increased the impact strength of composites. Addition of GNPs decreased the average water uptake and thickness swelling by 35% and 30%, respectively, compared to the control sample (without GNPs). It was observed that the composites filled with GNPs decomposed at higher temperatures compared to the pure PP and control. In all cases, the degradation temperatures shifted to higher values after the addition of GNPs. The improvement of physical and mechanical properties of composites confirmed that GNPs have good reinforcement and the optimum effect of GNPs was achieved at 0.8 wt.%.

Preparation and characterization of bagasse/HDPE composites using multi-walled carbon nanotubes.

This article presents the preparation and characterization of bagasse/high density polyethylene (HDPE) composites. The effects of multi-walled carbon nanotubes (MWCNTs), as reinforcing agent, on the mechanical and physical properties were also investigated. In order to increase the interphase adhesion, maleic anhydride grafted polyethylene (MAPE) was added as a coupling agent to all the composites studied. In the sample preparation, MWCNTs and MAPE contents were used as variable factors. The morphology of the specimens was characterized using scanning electron microscopy (SEM) technique. The results of strength measurement indicated that when 1.5 wt% MWCNTs were added, tensile and flexural properties reached their maximum values. At high level of MWCNTs loading (3 or 4 wt%), increased population of MWCNTs lead to agglomeration and stress transfer gets blocked. The addition of MWCNTs filler slightly decreased the impact strength of composites. Both mechanical and physical properties were improved when 4 wt% MAPE was applied. SEM micrographs also showed that the surface roughness improved with increasing MAPE loading from 0 to 4 wt%. The improvement of physicomechanical properties of composites confirmed that MWCNTs have good reinforcement and the optimum synergistic effect of MWCNTs and MAPE was achieved at the combination of 1.5 and 4 wt%, respectively.

Hybrid composites made from recycled materials: moisture absorption and thickness swelling behavior.

In this research, hybrid composite materials were made from the combination of recycled newspaper fiber (RNF) and poplar wood flour (PWF) as reinforcement, recycled polypropylene (RPP) as polymer matrix, and maleated polypropylene (MAPP) as coupling agent, by using injection molding. The effects of weight fractions of fibers and coupling agent concentration on the physical properties of the composites in terms of water absorption and thickness were studied. Composites containing more fraction of RNF exhibited maximum water absorption during the whole duration of immersion. This effect can be explained by the presence of a high amount of holocellulose present in the RNF, compared to the PWF. The addition of MAPP exhibited a beneficial effect on both the water absorption and thickness swelling by improving the quality of adhesion between polymer and fibers.

4-(4-Pyrid-yl)pyridinium bis-(pyridine-2,6-dicarboxyl-ato)ferrate(III) tetra-hydrate.

In the title compound, (C(10)H(9)N(2))[Fe(C(7)H(3)NO(4))(2)]·4H(2)O or (bpyH)[Fe(pydc)(2)]·4H(2)O, the asymmetric unit contains an [Fe(pydc)(2)](-) (pydcH(2)= pyridine-2,6-dicarboxylic acid) anion, a protonated 4,4'-bipyridine as a counter-ion, (bpyH)(+), and four uncoordinated water mol-ecules. The anion is a six-coordinate complex with a distorted octa-hedral geometry around the Fe(III )atom. A wide range of non-covalent inter-actions, i.e. O-H⋯O, O-H⋯N and N-H⋯O hydrogen bonds, ion pairing, C-O⋯π [3.431 (2) Å] and C-H⋯π stacking inter-actions result in the formation of a three-dimensional network structure.