A Starting Point on Recycling Land and Sea Snail Shell Wastes to Manufacture Quicklime, Milk of Lime, and Hydrated Lime.

The valorization of gastropod shell wastes in the production of lime is the topic of this study. First, shells from land snail and sea snail were characterized for their mineralogical, chemical, and thermal properties. Then, the shells were calcined at 1000 °C, and the obtained quicklimes were characterized for their specific surface area, pore diameter, and particle morphology, followed by evaluation of their reactivity in wet slaking tests.

Rheology of Suspensions of TEMPO-Oxidised and Cationic Cellulose Nanofibrils-The Effect of Chemical Pre-Treatment.

Cellulose nanofibrils (CNFs) are particles with a high aspect ratio. Typically, chemically pre-treated CNFs (containing anionic or cationic charged groups) consist of long fibrils (up to 2 μm) with very low thickness (less than 10 nm). Derived from their high aspect ratio, CNFs form strong hydrogels with high elasticity at low concentrations.

Nanocelluloses and Their Applications in Conservation and Restoration of Historical Documents.

Nanocelluloses have gained significant attention in recent years due to their singular properties (good biocompatibility, high optical transparency and mechanical strength, large specific surface area, and good film-forming ability) and wide-ranging applications (paper, food packaging, textiles, electronics, and biomedical). This article is a comprehensive review of the applications of nanocelluloses (cellulose nanocrystals, cellulose nanofibrils, and bacterial nanocellulose) in the conservation and restoration of historical paper documents, including their preparation methods and main properties. The novelty lies in the information collected about nanocelluloses as renewable, environmentally friendly, and sustainable materials in the field of cultural heritage preservation as an alternative to conventional methods.

Anionic bio-flocculants from sugarcane for purification of sucrose: An application of circular bioeconomy.

In sugar production, polyacrylamide-based anionic flocculants are added for juice treatment, the main objective being to remove impurities that affect the quality of the sugar. However, if they remain in the final product, those polymers can present carcinogenic and neurotoxic actions besides contaminating the soils where the waste is discharged. To overcome this problem, the present study proposes, for the first time, natural flocculants based on cellulose obtained from sugarcane bagasse (residue from sugarcane processing) as substitutes for the flocculants based on polyacrylamide, normally used in sugar cane juice purification.

Impact of bacterial cellulose on the physical properties and printing quality of fine papers.

Bacterial nanocellulose (BNC), due to its inherent nanometric scale and strength properties, can be considered as a good candidate to be used in papermaking. This work explored the possibility of using it in the production of fine paper as a wet-end component and for the paper coating. Filler-containing handsheet production was performed with and without the presence of common additives typically used in the furnish of office papers.

Acacia Wood Fractionation Using Deep Eutectic Solvents: Extraction, Recovery, and Characterization of the Different Fractions.

The selective extraction and recovery of different lignocellulosic molecules of interest from forestry residues is increasing every day not only to satisfy the needs of driving a society toward more sustainable approaches and materials (rethinking waste as a valuable resource) but also because lignocellulosic molecules have several applications. For this purpose, the development of new sustainable and ecologically benign extraction approaches has grown significantly. Deep eutectic solvents (DESs) appear as a promising alternative for the processing and manipulation of biomass.

High-performance delignification of invasive tree species wood with ionic liquid and deep eutectic solvent for the production of cellulose-based polyelectrolytes.

An efficient and eco-friendly process for lignocellulosic biomass fractionation is essential for the production of high value-added bioproducts from biomass. The present work aimed to obtain cellulose-rich materials from the wood of an invasive tree species () using an appropriate choice of ionic liquids (ILs) and deep eutectic solvents (DESs), and of the processing conditions, for the subsequent production of cationic wood-based polyelectrolytes. In the pretreatment step, the 1-butyl-3-methylimidazolium methyl sulfate (IL) + HO and choline chloride + imidazole (DES) systems demonstrated a remarkable ability to remove lignin from acacia, reaching up to 92.

Comparison of Surface Properties of Sepiolite and Palygorskite: Surface Energy and Nanoroughness.

The surface properties of two sepiolite samples and one palygorskite sample were compared using inverse gas chromatography (IGC). Samples were previously conditioned at appropriate temperatures for the removal of all zeolitic water. Dispersive (or Lifshitz-van der Waals) component of the surface energy (γ), specific interactions (-ΔG) with π electron donor bases (1-alkenes), and nanomorphology indices (IMχT) based on the injections of cycloalkanes and a branched alkane were measured.

Stabilization of Palygorskite Aqueous Suspensions Using Bio-Based and Synthetic Polyelectrolytes.

Palygorskite is a natural fibrous clay mineral that can be used in several applications, for which colloidal stability in aqueous suspensions is a key point to improve its performance. In this study, methods of magnetic stirring, high-speed shearing, and ultrasonication, as well as different chemical dispersants, combined with these methods, namely carboxymethylcellulose, alginate, polyphosphate, and polyacrylate, were used to improve the dispersibility and the formation of stable suspensions of palygorskite in different conditions of pH. The stability and particle size of suspensions with a low concentration of palygorskite were evaluated by visual inspection, optical and electron microscopy, dynamic light scattering, and zeta potential measurements.

Evaluation of Anionic Eco-Friendly Flocculants Prepared from Eucalyptus Pulps with Diverse Lignin Contents for Application in Effluent Treatment.

Modification of cellulosic-rich materials for the production of cellulose-based polyelectrolytes (PELs) can bring several benefits, such as high biodegradability and low or no toxicity, for numerous applications, when compared with the use of traditional, synthetic PELs. Moreover, cellulose-based PELs originating from wood wastes, contribute to the valorisation of such wastes. In this work, pulps with diverse lignin contents, extracted from wood wastes, were anionized by a two-step reaction procedure (periodate oxidation followed by sulfonation).

Characterization of Two Cactus Formulation-Based Flocculants and Investigation on Their Flocculating Ability for Cationic and Anionic Dyes Removal.

Dye invasion in wastewaters is undeniably one of the crucial environmental concerns in addition to the supplement of toxic synthetic chemical flocculants used for color removal using the conventional coagulation-flocculation process. With the aim to improve the flocculation stage in terms of reagents safety and ensure dyes removal, the present study explores the flocculating effectiveness of two natural, stable, and eco-friendly cactus formulations, namely 60 °C oven-dried (DP) and lyophilized (LP) cladodes. Both formulations were assessed to treat cationic (Methylene blue; MB) and anionic (Methyl Orange; MO) dye solutions as a substitution attempt for the currently questioned employed synthetic chemical flocculants.

A new formaldehyde optical sensor: Detecting milk adulteration.

A sensor consisting of an optical fibre with the exposed tip coated with the polyoxometalate salt [(CH)N]H[PMoVO], specially designed to be insoluble in water, which UV-Vis spectrum changed in contact with formaldehyde, is presented. The sensor limit of detection for formaldehyde was 0.2 mg L, and the limit of quantification was 0.

Evaluation of Anionic and Cationic Pulp-Based Flocculants With Diverse Lignin Contents for Application in Effluent Treatment From the Textile Industry: Flocculation Monitoring.

In wastewater treatment, flocculation is a widely used solid/liquid separation technique, which typically employs a charged polymer, a polyelectrolyte (PEL). Polyelectrolytes features, such as charge type, charge density and molecular weight, are essential parameters affecting the mechanism of flocculation and subsequent floc sedimentation. The effectiveness of the process is also influenced by the characteristics of the system (e.

Cationization of wood waste pulps with diverse lignin contents for potential application in colored wastewater treatment.

Modification of cellulosic-rich materials such as wood waste and production of cellulose-based polyelectrolytes (PELs) presents several advantages for a variety of applications, when compared to the utilization of synthetic PELs, due to the nature, availability, high biodegradability and low or no toxicity of cellulosic materials. Moreover, valorization of the cellulosic waste itself to provide end products with higher added value is also an important aspect. In the present work, the objective was to evaluate the possibility of cationizing more complex and heterogeneous chemical pulps, obtained from wood waste, with different cellulose purity and a relatively high lignin content (up to 4.

Enzymatic nanocellulose in papermaking - The key role as filler flocculant and strengthening agent.

Nanocelluloses have been increasingly used in composites since their reduced size, high aspect ratio and stiffness confer great strength to the materials. In papermaking, it has been proved that harsh and expensive chemical pre-treatments to generate nanofibrils, such as TEMPO-mediated oxidation, are not the most favourable and therefore the use of cellulose microfibrils (CMF) have gained extra attention, especially those produced with the aid of enzymatic hydrolysis. In the present work, strategies to improve filler flocculation and the papermaking properties, by using enzymatic CMF, are provided.

Up-scaling of tannin-based coagulants for wastewater treatment: performance in a water treatment plant.

Tannin extracts from the bark of Acacia mearnsii and wood of Schinopsis balansae, commonly known as Quebracho, were employed. These were modified at laboratory sale via the Mannich aminomethylation with formaldehyde and dimethylamine hydrochloride. Some reaction conditions were varied, namely the formaldehyde dosage and reaction time, while keeping the Mannich solution activation time constant, and their influence on the shear viscosity of the created bio-coagulants was evaluated.

Environmentally friendly cellulose-based polyelectrolytes in wastewater treatment.

Natural-based polyelectrolytes (PELs), with all the advantages coming from being produced from renewable and biodegradable sources, are a potential solution for the removal of dyes from wastewater. In this work, surplus Eucalyptus bleached cellulose fibres from a paper mill were modified to increase the charge and solubility of cellulose. First, reactive aldehyde groups were introduced in the cellulose backbone by periodate oxidation of cellulose.

Determination of 5-hydroxymethylfurfural in honey, using headspace-solid-phase microextraction coupled with a polyoxometalate-coated piezoelectric quartz crystal.

High concentrations of 5-hydroxymethylfurfural (HMF) in honey provide an indication of overheating under inappropriate storage conditions or aging. Conventional methods for determining HMF are cumbersome and require expensive equipment or hazardous reagents. Hence the aim of this study was to propose a new analytical tool for HMF determination in honey, using a low cost acoustic wave sensor.

On the morphology of cellulose nanofibrils obtained by TEMPO-mediated oxidation and mechanical treatment.

The morphological properties of cellulose nanofibrils obtained from eucalyptus pulp fibres were assessed. Two samples were produced with the same chemical treatment (NaClO/NaBr/TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl radical) oxidation), but distinct mechanical treatment intensities during homogenization. It was shown that the nanofibrils production yield increases with the mechanical energy.

Nanostructured bacterial cellulose-poly(4-styrene sulfonic acid) composite membranes with high storage modulus and protonic conductivity.

The present study reports the development of a new generation of bio-based nanocomposite proton exchange membranes based on bacterial cellulose (BC) and poly(4-styrene sulfonic acid) (PSSA), produced by in situ free radical polymerization of sodium 4-styrenesulfonate using poly(ethylene glycol) diacrylate (PEGDA) as cross-linker, followed by conversion of the ensuing polymer into the acidic form. The BC nanofibrilar network endows the composite membranes with excellent mechanical properties at least up to 140 °C, a temperature where either pure PSSA or Nafion are soft, as shown by dynamic mechanical analysis. The large concentration of sulfonic acid groups in PSSA is responsible for the high ionic exchange capacity of the composite membranes, reaching 2.

Polyoxometalate/laccase-mediated oxidative polymerization of catechol for textile dyeing.

The synergistic effect between polyoxometalates (POMs), namely K(5)[SiW(11)V(V)O(40)]·11H(2)O and H(5)[PMo(10)V(V) (2)O(40)]·13H(2)O and laccase from ascomycete Myceliophthora thermophila has been employed for the first time in oxidative polymerization of catechol. Such a laccase-mediator system allowed the formation of a relatively high molecular weight polycatechol as confirmed by size exclusion chromatography and electrospray ionization mass spectrometry (ESI-MS) (3990 Da when using K(5)[SiW(11)V(V)O(40)]·11H(2)O and 3600 Da with H(5)[PMo(10)V(V) (2)O(40)]·13H(2)O). The synthesized polymers were applied as dyes for the dyeing of flax fabrics.

Delignification of eucalypt kraft pulp with manganese-substituted polyoxometalate assisted by fungal versatile peroxidase.

Oxidation of the manganese-substituted polyoxometalate [SiW(11)Mn(II)(H(2)O)O(39)](6-) (SiW(11)Mn(II)) to [SiW(11)Mn(III)(H(2)O)O(39)](5-) (SiW(11)Mn(III)), one of the most selective polyoxometalates for the kraft pulp delignification, by versatile peroxidase (VP) was studied. First, SiW(11)Mn(II) was demonstrated to be quickly oxidized by VP at room temperature in the presence of H(2)O(2) (K(m)=6.4+/-0.

Multisensor system for determination of polyoxometalates containing vanadium at its different oxidation states.

The electronic tongue (ET) multisensor system has been employed for the detection of metal-oxygen cluster anions (polyoxometalates) containing vanadium (IV/V) atoms. Sensitivity of a variety of potentiometric chemical sensors with plasticized polyvinyl chloride and chalcogenide glass membranes was evaluated with respect to vanadyl/vanadate ions, decavanadate and a series of Keggin-type polyoxometalates (POM) such as alpha-[SiW(11)V(IV)O(40)](6-), alpha-[SiW(11)V(V)O(40)](5-), alpha-[BW(11)V(IV)O(40)](7-), alpha-[BW(11)V(V)O(40)](6-), alpha-[PW(11)V(IV)O(40)](5-) and alpha-[PW(12-n)V(n)(V)O(40)]((3+n)-) (n=1, 2, 3). Sensor's responses to vanadium complexes were evaluated in the pH range of 2.