Synthesis of Mg-Al Hydrotalcite Clay with High Adsorption Capacity

A novel Mg-Al metal oxide has been successfully synthesized by the calcination of hierarchical porous Mg-Al hydrotalcite clay obtained by using filter paper as a template under hydrothermal conditions. Various characterizations of the obtained nanoscale oxide particles verified the uniform dispersion of Mg-Al metal oxides on the filter paper fiber, which had a size of 2–20 nm and a highest specific surface area (SSA) of 178.84 m2/g. Structural characterization revealed that the as-prepared Mg-Al metal oxides preserved the tubular morphology of the filter paper fibers. Further experiments showed that the as-synthesized Mg-Al metal oxides, present at concentrations of 0.3 g/L, could efficiently remove sulfonated lignite from oilfield wastewater (initial concentration of 200 mg/L) in a neutral environment (pH = 7) at a temperature of 298 K. An investigation of the reaction kinetics found that the adsorption process of sulfonated lignite (SL) on biomorphic Mg-Al metal oxides fits a Langmuir adsorption model and pseudo-second-order rate equation. Thermodynamic calculations propose that the adsorption of sulfonated lignite was spontaneous, endothermic, and a thermodynamically feasible process.

New circular building composite material to upcycle building wastes

A new class of sustainable building composite materials is developed, made out of recycled fibers waste, of sand from crushing inert waste and of lime. The fibers come from abundant and available bio-based or mineral fibers such as cellulose, glass wool, or rock wool. The crushing sand comes from inert building waste and is used instead of river sand which is a resource under shortage. Lime is, like the other two constituents, available locally. The targeted performance is minimizing the environmental footprint compared to the current building materials available on the market in terms of CO2 emissions and grey energy consumption over the entire life cycle. Additional specific objectives are a lifetime up to 60 years, the incorporation of at least 75% recycled or end-of-cycle materials and a high potential of further reuse or recycling. These performances must be optimized under all the structural, thermal and durability constraints of specific building applications. A test campaign has proved the energy-efficient nature of the processing and excellent potential in terms of insulation, fire resistance and mechanical strength, for materials containing a rate of paper fibers larger than 50%.

Beneficial effect of gelatin on iron gall ink corrosion

Iron gall Inks corrosion causes paper degradation (browning, embrittlement) and treatments were developed to tackle this issue. They often include resizing with gelatin to reinforce the paper and its cellulosic fibers (of diameter approx. 10 µm). This work aimed at measuring the distribution of ink components at the scale of individual paper fibers so as to give a better understanding of the impact of gelatin (re-)sizing on iron gall ink corrosion. For this purpose, scanning transmission X-ray microscopy (STXM) was used at the Canadian light source synchrotron (CLS, Saskatoon). This technique combines nano-scale mapping (resolution of 30 nm) and near edge X-ray absorption fine structure (NEXAFS) analysis. Fe L-edge measurements enabled to map iron distribution and to locate iron(II) and iron(III) rich areas. N K-edge measurement made it possible to map gelatin distribution. C K-edge measurements allowed mapping and discrimination of cellulose, gallic acid, iron gall ink precipitate and gelatin. Three fibers were studied: an inked fiber with no size, a sized fiber that was afterwards inked and an inked fiber sprayed with gelatin. Analysis of gelatin and ink ingredients distribution indicated a lower amount of iron inside the treated cellulosic fiber, which may explain the beneficial effect of gelatin on iron gall ink corrosion.

Application of frankincense and rice starch as eco-friendly substances for the resizing of paper as a conservation practice

Smart, environmentally friendly alternatives, i.e., frankincense and rice starch, are recommended for usage in modern paper conservation processes during the re-sizing process treatments. Different concentrations of frankincense and rice starch were applied to paper samples before and after ageing. Multiple analysis methods were performed to ensure the effectiveness of these materials. Promising results were found, but at varying degrees according to the type and concentration of the materials. Scanning electron microscopy illustrated that the frankincense particles were completely absorbed into the cell walls after ageing. Results indicated that there was no considerable change in pH before and after treatment or ageing; the best results for decreasing the acidity utilized a treatment with a mixture of frankincense and rice starch in a 2 to 1 ratio (F2S1). Fourier transform infrared spectroscopy illustrated an increased CH2 region and decreased OH stretching as a result of the bonds formed from the starch and crystals formed by frankincense, which agreed with the increased coating and strength of the paper fibers. The total color change values of all the treated samples after ageing were less than 4.5. Frankincense was found to provide strength in supporting wood fibers.

Effect of Nanocellulose on the Properties of Cottonseed Protein Isolate as a Paper Strength Agent

Currently, there is an increasing interest in the use of biopolymers in industrial applications to replace petroleum-based additives, since they are abundantly available, renewable and sustainable. Cottonseed protein is a biopolymer that, when used as a modifier, has shown improved performance for wood adhesives and paper products. Thus, it would be useful to explore the feasibility of using cellulose nanomaterials to further improve the performance of cottonseed protein as a paper strength agent. This research characterized the performance of cottonseed protein isolate with/without cellulose nanofibers (CNFs) and cellulose nanocrystals (CNCs) to increase the dry strength of filter paper. An application of 10% protein solution with CNCs (10:1) or CNFs (50:1) improved the elongation at break, tensile strength and modulus of treated paper products compared to the improved performance of cottonseed protein alone. Further analysis using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) indicated that the cottonseed protein/nanocellulose composites interacted with the filter paper fibers, imparting an increased dry strength.

FIBER CLASSIFICATION, PHYSICAL AND OPTICAL PROPERTIES OF RECYCLED PAPER

"In this study, reference papers prepared in accordance with the INGEDE 11p standard (International Association of the Deinking Industry) were recycled three times. Initially, reference papers were subjected to wetting, pulping, storage, deinking, dispersing and bleaching processes. At the end of these processes, test papers were produced and their optical characteristics were examined. The brightness value of writing papers (of 80 grams) was determined to be of 86%, following the TS 11610:2017 standard. In order to bring the brightness of the produced laboratory test papers to the specified value, double-stage bleaching was applied: with 0.4% FAS in the first stage and H2O2 in the second stage. The physical and optical properties of the test papers that reached the standard brightness value were determined. Overall, the final products were recycled three times. At the end of the third recycling stage, changes in paper fibers were examined. As a result, it was observed that the breaking, tear and burst resistance of the obtained papers gradually decreased at the end of each recycling stage. In addition, because of the narrowing fiber surface, it was determined that the opacity value of the paper decreased at the end of each recycling stage. According to the fiber classification results, the fiber size shrank at the end of the third recycling stage and a large part of the fibers remained in the 200 mesh. Paper fibers are recycled 3.6 times in Europe. This rate is approximately 2.4 times higher than the world average. This study offers interesting results regarding cellulose recycling, which has gained great importance in recent years. "

Gelatin, a protective agent against iron gall ink corrosion?

Iron gall Inks are known to promote paper degradation, thus jeopardizing the conservation of written Heritage. This phenomenon, also called iron gall ink corrosion, is not only governed by chemical reactions occurring between ink constituents and cellulose (the main constituent of paper) but also by the penetration of ink components inside the paper. This penetration depends on the ability of water and ink soluble components to migrate inside the sheet. This latter is composed of hydrophilic cellulosic fibers (of diameter approx. 10 µm) embedded in a size that lowers water affinity and thus makes it suitable for writing. This work aims to better understand the impact of gelatin size on iron gall ink corrosion by investigating the distribution of gelatin and ink components at the scale of individual paper fibers. STXM, a nano-scale mapping technique (resolution of 30 nm) that also allows NEXAFS analysis was used for this purpose. Fe L-edge measurements enabled to map iron distribution and to locate iron(II) and iron(III) rich areas. N K-edge measurement made it possible to map gelatin distribution. C K-edge measurements allowed mapping and discrimination of cellulose, gallic acid, iron gall ink precipitate and gelatin. Three fibers were studied: an inked fiber with no size, a sized fiber that was afterwards inked and an inked fiber sprayed with gelatin (to model the impact of conservation treatments that use gelatin as a re-sizing agent). Analysis of gelatin and ink ingredients distribution inside and outside the cellulosic fiber gave some clues to account for the limiting impact of gelatin on iron gall ink corrosion.

Recycling of Aseptic Beverage Cartons: A Review

Aseptic beverage cartons are multilayer polymer-coated paperboards with a layer of aluminum foil. Due to their multilayer structure it is commonly assumed that they cannot be recycled. This is not the case and this review details the multifarious processes that are used to recycle aseptic beverage cartons. Hydrapulping to recover the paper fibers that constitute 75% of the carton is the most widespread process, followed by the manufacture of construction materials such as boards and tiles which utilize the complete carton. A range of mechanical, chemical and thermal processes are used to separate the PolyAl (polyethylene and aluminum) residual that remains after the paper fibers have been recovered. The simplest process involves agglutination followed by extrusion to obtain pellets that can then be used in industrial and consumer products or combined with other materials such as lignocellulosic wastes. Chemical approaches involve the solubilization of polyethylene and the removal of aluminum. Various thermal processes have also been investigated and a novel microwave-induced pyrolysis process appears the most commercially viable. It is concluded that the focus in future years is likely to be on recycling cartons into construction materials where there is a theoretical yield of 100% compared with 75% for hydrapulping.

Model Surfaces for Paper Fibers Prepared from Carboxymethyl Cellulose and Polycations

For tailored functionalization of cellulose based papers, the interaction between paper fibers and functional additives must be understood. Planar cellulose surfaces represent a suitable model system for studying the binding of additives. In this work, polyelectrolyte multilayers (PEMs) are prepared by alternating dip-coating of the negatively charged cellulose derivate carboxymethyl cellulose and a polycation, either polydiallyldimethylammonium chloride (PDADMAC) or chitosan (CHI). The parameters varied during PEM formation are the concentrations (0.1–5 g/L) and pH (pH = 2–6) of the dipping solutions. Both PEM systems grow exponentially, revealing a high mobility of the polyelectrolytes (PEs). The pH-tunable charge density leads to PEMs with different surface topographies. Quartz crystal microbalance experiments with dissipation monitoring (QCM-D) reveal the pronounced viscoelastic properties of the PEMs. Ellipsometry and atomic force microscopy (AFM) measurements show that the strong and highly charged polycation PDADMAC leads to the formation of smooth PEMs. The weak polycation CHI forms cellulose model surfaces with higher film thicknesses and a tunable roughness. Both PEM systems exhibit a high water uptake when exposed to a humid environment, with the PDADMAC/carboxymethyl cellulose (CMC) PEMs resulting in a water uptake up to 60% and CHI/CMC up to 20%. The resulting PEMs are water-stable, but water swellable model surfaces with a controllable roughness and topography.