Photoluminescent biocomposite films of chitosan based on styrylbenzothiazolium-g-cellulose nanocrystal for anti-counterfeiting applications

Properties of Biocomposites Made of Extruded Apple Pomace and Potato Starch: Mechanical and Physicochemical Properties

This paper presents research results on biocomposites made from a combination of extruded apple pomace (EAP) and potato starch (SP). The aim of this work was to investigate the basic properties of biocomposites obtained from extruded apple pomace reinforced with potato starch. The products were manufactured by hot pressing using a hydraulic press with a mould for producing samples. The prepared biocomposites were subjected to strength tests, surface wettability was determined, and a colour analysis was carried out. A thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), and cross-sectioning observed in a scanning electron microscope (SEM) were also performed. The obtained test results showed that the combination of apple pomace (EAP) and starch (SP) enabled the production of compact biocomposite materials. At the same time, it was found that each increase in the share of starch in the mixture for producing biocomposites increased the strength parameters of the obtained materials. With the highest share of starch in the mixture, 40%, and a raw material moisture content of 14%, the material had the best strength parameters and was even characterised by hydrophobic properties. It was also found that materials with a high content of starch are characterised by increased temperature resistance. The analysis of SEM microscopic photos showed well-glued particles of apple pomace, pectin, and gelatinised starch and a smooth external structure of the samples. Research and analyses have shown that apple pomace reinforced only with the addition of starch can be a promising raw material for the production of simple, biodegradable biocomposite materials.

Porous polyvinyl fluoride coated cellulose beads for efficient removal of Cd(II) from phosphoric acid

In order to enhance the removal of cadmium from phosphoric acid, it is imperative to explore novel resources that may be utilized for the development of highly effective and environmentally sustainable adsorbents. Cellulose beads are composed of naturally occurring polysaccharide fibers and find extensive utilization across several industrial sectors and applications. Within this framework, this research paper presents a green and simple method for producing porous cellulose beads using date palm fibers as the preferred raw material. The innovation lies in immersing the obtained cellulose beads in a Polyvinyl fluoride (PVDF)/N,N-dimethylformamide (DMF) suspension as a coating polymer with different concentrations (2.5, 5, 10 %) to maintain their stability in an acidic environment. The surface of cellulose/PVDF beads were subjected to multiple characterizations like Fourier transform infrared (FTIR) spectroscopy, Scanning electron microscopy (SEM), Thermogravimetric analysis (TGA), size distribution then pH stability confirming that the coating has been perfectly achieved and conserved well the shape of the beads. The coated cellulose/PVDF-2.5 % underwent evaluation by the process of batch adsorption experiments while different parameters were varied including contact time (5, 10, 20, 30, 60, 90 min), temperature (25, 35, 45 and 55 °C), and adsorbent mass (20, 40, 60, 80 and 100 mg). The obtained ICP data showed that the adsorption rate of Cd (II) from phosphoric acid medium decreased while increasing both temperature from 25 to 55 °C and contact time from 5 to 90 min while adding more adsorbent dosage from 20 to 100 mg enhanced the removal percentage. The cellulose/PVDF-2.5 % was more effective with an adsorption capacity equal to 3.4998 mg/g at optimal conditions including 25 °C as the temperature after 5 min as contact time and by adding a mass 100 mg of the biosorbent while the pH = 2 of the solution is maintained the same. The examined material's adsorption processes proved to be exothermic and non-spontaneous, and it proved that the pseudo-second-order model provided the best match for the cellulose/PVDF-2.5 % beads kinetics data. Furthermore, the cellulose beads exhibited exceptional reusability for up to four repeated cycles without undergoing desorption. The present study offers a viable approach for producing environmentally sustainable biomass-derived adsorbents. Additionally, the study validates the potential of cellulose/PVDF beads as an intriguing material for phosphoric acid decadmiation.

Design and experimental study on closed-loop process of preparing chitosan from crab shells

The purpose of this article is to design a green and comprehensive utilization process for preparing chitosan from crab shells. Glutamate acid was used as a decalcifying agent for crab shells, and the mixed solution of potassium hydroxide/isopropanol was used for deproteinization and deacetylation to prepare chitosan. Glutamic acid and isopropanol could be recovered for recycling. At the same time, calcium carbonate and protein in crab shells were converted into calcium hydrogen phosphate and compound fertilizer containing nitrogen, phosphorus, and potassium, respectively. The prepared chitosan was characterized by Fourier-transform infrared (FT-IR), differential scanning calorimetry (DSC), x-ray diffraction (XRD), and scanning electron microscopy (SEM), and its deacetylation degree and viscosity average molecular weight were 88.7% ± 0.68% and 792.1 ± 10.82 kDa, respectively. The recoveries of glutamic acid and isopropanol were 95.56% ± 1.39% and 88.14% ± 1.13%, respectively. The prepared chitosan has large molecular weight and deacetylation degree, controllable production cost, comprehensive utilization of crab shell components, and greatly reduced waste emissions.

Cellulose as an Eco-Friendly and Sustainable Material for Optical Anticounterfeiting Applications: An Up-to-Date Appraisal

The falsification of documents, currency, pharmaceuticals, branded goods, clothing, food products, and packaging leads to severe consequences. Counterfeited products can not only pose health risks to consumers but also cause substantial economic losses that can negatively impact the global markets. Unfortunately, most anticounterfeiting strategies are easily duplicated due to rapid technological advancements. Therefore, innovative and cost-effective antiforgery techniques that can offer superior multilevel security features are continuously sought after. Due to the ever-growing global awareness of environmental pollution, renewable and eco-friendly native biopolymers are garnering wide attention in anticounterfeiting applications. This review highlights the potential use of cellulose-based eco-friendly materials to combat the counterfeiting of goods. The initial section of the review focuses on the structure, properties, and chemical modifications of cellulose as a sustainable biomaterial. Further, the topical developments reported on cellulose and nanocellulose-based materials used as fluorescent security inks, films, and papers for achieving protection against counterfeiting are presented. The studies suggest the convenient use of celluose and modified cellulose materials for promising optical antiforgery applications. Furthermore, the scope for future research developments is also discussed based on the current critical challenges in the fabrication of cellulose-based materials and their anticounterfeit applications.