Silver nanoparticles incorporated with superior silica nanoparticles-based rice straw to maximize biogas production from anaerobic digestion of landfill leachate.

Treating hazardous landfill leachate poses significant environmental challenges due to its complex nature. In this study, we propose a novel approach for enhancing the anaerobic digestion of landfill leachate using silver nanoparticles (Ag NPs) conjugated with eco-friendly green silica nanoparticles (Si NPs). The synthesized Si NPs and Ag@Si NPs were characterized using various analytical techniques, including transmission electron microscopy, X-ray diffraction, and Fourier-transform infrared spectroscopy. The anaerobic digestion performance of Si NPs and Ag@Si NPs was tested by treating landfill leachate samples with 50 mg/L of each NP. The results demonstrated an enhancement in the biogas production rate compared to the control phase without the nanocomposite, as the biogas production increased by 14% and 37% using Si NPs and Ag@Si NPs. Ag@Si NPs effectively promoted the degradation of organic pollutants in the leachate, regarding chemical oxygen demand (COD) and volatile solids (VS) by 58% and 65%. Furthermore, microbial analysis revealed that Ag@Si NPs enhanced the activity of microbial species responsible for the methanogenic process. Overall, incorporating AgNPs conjugated with eco-friendly green Si NPs represents a sustainable and efficient approach for enhancing the anaerobic digestion of landfill leachate.

Effect of organic loading rates on the performance of membrane bioreactor for wastewater treatment behaviours, fouling, and economic cost.

Although submerged membrane bioreactor (MBR) are widely used in treating municipal wastewater and recovery of potential resources, membrane operational parameters and membrane fouling control remain debated issues. In this study, the treatment of municipal wastewater by MBR at high-biomass sludge (MLSS (g/L) ranging from 5.4 g/L to 16.1 g/L) was assessed at an organic loading rates (OLRs) ranging from 0.86 to 3.7 kg COD/m3d. The correlation between trans-membrane pressure and total fouling resistance was thoroughly investigated in this study. According to the findings, greater OLRs of 0.86 to 3.7 kg COD/m3d caused a decrease in COD, BOD, and NH4-N removal efficiency, and higher OLRs of 3.7 kg COD/m3d resulted in a higher increase in total fouling resistance (Rt). The economic study of using the MBR system proved that for a designed flow rate of 20 m3/d, the payback period from using the treated wastewater will be 7.98 years, which confirms the economic benefits of using this MBR for treating municipal wastewater. In general, understanding the challenges facing the efficiency of MBR would improve its performance and, consequently, the sustainability of wastewater reclamation.

Multifunction smart nanocomposite film for food packaging based on carboxymethyl cellulose/Kombucha SCOBY/pomegranate anthocyanin pigment.

Active packing systems employed to preserve food quality have gone through chains of sustainable development processes, reflecting the growth in consumer awareness of high-quality foods in eco-friendly packaging. Consequently, this study aims to develop antioxidant, antimicrobial, UV-shielding, pH-sensitive, edible, and flexible films from composites of carboxymethyl cellulose (CMC), pomegranate anthocyanin extract (PAE), and various fractions (1-15 %) of bacterial cellulose from the Kombucha SCOBY (BC Kombucha). Various analytical tools such as ATR-FTIR, XRD, TGA, and TEM were utilized to investigate the physicochemical characterization of BC Kombucha and CMC-PAE/BC Kombucha films. The DDPH scavenging test demonstrated the efficiency of PAE as a matrix with potent antioxidant properties, both as a solution and enclosed in composite films. The fabricated films of CMC-PAE/BC Kombucha showed antimicrobial activities against many pathogenic Gram-negative (Pseudomonas aeruginosa, Salmonella sp., and Escherichia coli), Gram-positive (Listeria monocytogenes and Staphylococcus aureus) bacteria, and Candida albicans, ranging from a 20 to 30 mm inhibition zone. The CMC-PAE/BC Kombucha nanocomposite has additionally been utilized to pack red grapes and plums. The results illustrated that CMC-PAE/BC Kombucha nanocomposite can increase red grapes and plums' shelf lives by up to 25 days while maintaining the fruits' quality better than those left unpacked.

Immobilization of TiO2NP@ oxidized cellulose nanocrystals for paper-based active packaging materials.

In the current work, we present a renewable alternative coating formulation made of durable titania nanoparticles and oxidized nanocellulose (TiO2NPs@OCNs) nanocomposites and sodium alginate (SA), to create an environmentally friendly and secure food packaging paper. OCNs sugarcane fibers are firstly hydrolyzed using ammonium persulphate (APS). Then, TiO2NPs@OCNs nanocomposites are made in situ with OCNs using a green water-based sol-gel synthesis. Gram (+) microorganisms as well as Gram (-) bacteria are used to test the antibacterial properties of the TiO2NPs@OCN dispersions. The results show that the TiO2NP@OCNs significantly decreases the growth for all bacterial species. The TiO2NP@OCNs nanocomposites are mixed with SA, and the resulting formulations are used to coat paper sheets. The corresponding physicochemical properties are evaluated using FTIR, TGA, AFM, SEM, and EDX. Furthermore, the mechanical strength, air permeability, and water vapor characteristics of the paper sheets treated with SA/TiO2NPs@OCN are carried out, resulting in a great improvement of these properties. Finally, the SA/TiO2NPs@OCNs coated papers have been used as packaging for strawberries. The findings demonstrate that coated papers could preserve strawberry quality better than unpacked fruit and extend strawberry shelf life from 6 to 18 days.

Boosting brackish water treatment via integration of mesoporous γ-Al2O3NPs with thin-film nanofiltration membranes.

In this study, a simple method based on non-ionic surfactant polysorbates-80 was used to create mesoporous γ-Al2O3NPs. The properties of the prepared mesoporous alumina nanoparticles (Al2O3NPs) were verified using ATR-FTIR, XRD, SEM, TEM, DLS, and BET surface area analysis. Then, thin-film nanocomposite (TFN) nanofiltration membranes were fabricated by interfacial polymerization of embedded polyamide layers with varied contents (0.01 to 0.15 wt.%) of mesoporous γ-Al2O3NPs. The surface roughness, porosity, pore size, and contact angle parameters of all the prepared membranes were also determined. The performance of the fabricated membranes was investigated under various mesoporous γ-Al2O3NPs loads, time, and pressure conditions. Mesoporous γ-Al2O3NPs revealed an important role in raising both the membrane hydrophilicity and the surface negativity. The addition of 0.03 wt.% mesoporous γ-Al2O3NPs to the TFN membrane increased water flux threefold compared to the TF control (TFC) membrane, with maximum water flux reaching 96.5, 98, 60, and 52 L/(m2.h) for MgSO4, MgCl2, Na2SO4, and NaCl influent solutions, respectively, with the highest salt rejection of 96.5%, 92.2%, 98.4%. The TFN-Al2O3 membrane was also able to soften water and remove polyvalent cations such as Mg2+ with a highly permeable flux. The TFN-Al2O3 membrane successfully removed the hardness of the applied water samples below the WHO limit compared to using merely the TFC membrane. Furthermore, the TFN-Al2O3 nanofiltration membrane unit proved to be a promising candidate for the desalination of real brine like that collected from the Safaga area, Egypt.

Green synthesis of cellulose nanocrystal/ZnO bio-nanocomposites exerting antibacterial activity and downregulating virulence toxigenic genes of food-poisoning bacteria.

Recently, cellulose nanocrystals (CNs) have attracted wide attention owing to their superior properties compared to their bulk materials. For example, they represent an outstanding model for fabricating green metallic/metal oxide nanoparticles (NPs). In this study, two CNs (carboxylated CNs and sulfated CNs) extracted from agro-wastes of palm sheath fibers were used as templates for the facile and green synthesis of ZnO NPs by employing the sono-co-precipitation method. The obtained nanomaterials were characterized using TEM, EDX, UV-visible, DLS, FT-IR, and XRD analysis. As a result, the size and concentration of synthesized ZnO NPs were inversely proportional to one another and were affected by the CNs utilized and the reaction temperature used. Contagious diseases incited by multifarious toxigenic bacteria present severe threats to human health. The fabricated bio-nanocomposites were evaluated in terms of their antimicrobial efficacy by agar well diffusion method and broth microdilution assay, showing that CN-ZnO bio-nanocomposites were effective against the tested Gram-negative (Escherichia coli and Salmonella) and Gram-positive (Listeria monocytogenes and Staphylococcus aureus) bacteria. The influence of the subinhibitory concentrations of these suspensions on the expression of the most critical virulence toxin genes of the tested strains was effective. Significant downregulation levels were observed through toxigenic operons to both fabricated CN-ZnO bio-nanocomposites with a fold change ranging from 0.004 to 0.510, revealing a decline in the capacity and virulence of microorganisms to pose infections. Therefore, these newly fabricated CNS-ZnO bio-nanocomposites could be employed rationally in food systems as a novel preservative to inhibit microbial growth and repress the synthesis of exotoxins.

A Facile One-Pot Approach to the Fabrication of Nanocellulose-Titanium Dioxide Nanocomposites with Promising Photocatalytic and Antimicrobial Activity.

The combination of cellulosic materials and metal oxide semiconductors can provide composites with superior functional properties compared to cellulose. By using nanocellulose derived from agricultural waste, we propose a one-pot and environmentally friendly approach to the synthesis of nanocellulose-TiO2 (NC-TiO2) nanocomposites with peculiar photocatalytic activity and antibacterial effects. The as-prepared NC-TiO2 composites were fully characterized by different techniques, such as X-ray diffraction (XRD), µ-Raman, Fourier transform infrared spectroscopy (FTIR), thermogravimetry analysis (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and diffuse reflectance spectroscopy (DRS). The results showed that well crystalline anatase TiO2 nanoparticles of about 5-6 nm were obtained. The photocatalytic activity in particular was evaluated by using methyl orange (MO) solution as a target pollutant at different pH values. It was found that all the tested NC-TiO2 nanocomposites showed stable photocatalytic activity, even after consecutive photocatalytic runs. In addition, NCT nanocomposites with higher TiO2 content showed degradation efficiency of almost 99% towards MO after 180 min of UV illumination. Finally, NC-TiO2 nanocomposites also showed intriguing antimicrobial properties, demonstrating to be effective against Gram-positive (Staphylococcus aureus, Bacillus subtilis) with 20-25 mm of inhibition zone and Gram-negative bacteria (Escherichia coli, Pseudomonas aeuroginosa) with 21-24 mm of inhibition zone, and fungi (Candida albicans) with 9-10 mm of inhibition zone.

Evaluation of Long-Lasting Antibacterial Properties and Cytotoxic Behavior of Functionalized Silver-Nanocellulose Composite.

Materials possessing long-term antibacterial behavior and high cytotoxicity are of extreme interest in several applications, from biomedical devices to food packaging. Furthermore, for the safeguard of the human health and the environment, it is also stringent keeping in mind the need to gather good functional performances with the development of ecofriendly materials and processes. In this study, we propose a green fabrication method for the synthesis of silver nanoparticles supported on oxidized nanocellulose (ONCs), acting as both template and reducing agent. The complete structural and morphological characterization shows that well-dispersed and crystalline Ag nanoparticles of about 10-20 nm were obtained in the cellulose matrix. The antibacterial properties of Ag-nanocomposites (Ag-ONCs) were evaluated through specific Agar diffusion tests against E. coli bacteria, and the results clearly demonstrate that Ag-ONCs possess high long-lasting antibacterial behavior, retained up to 85% growth bacteria inhibition, even after 30 days of incubation. Finally, cell viability assays reveal that Ag-ONCs show a significant cytotoxicity in mouse embryonic fibroblasts.

Fabrication of packaging paper sheets decorated with alginate/oxidized nanocellulose­silver nanoparticles bio-nanocomposite.

Packaging is as important as the product itself because it is a crucial marketing and communication tool for business. Oxidized nanocellulose (ONC), extracted from agriculture residues of bagasse raw material using ecofriendly ammonium persulfate hydrolysis method, is used as support/reducing agent for the generation of silver nanoparticles (AgNPs) via photochemical procedure and reinforcing element in paper functionalization. The natural polymer, sodium alginate (SA) is exploited to enhance the binding of the ONC-AgNPs over cellulose fibers. The SA/ONC-AgNPs bio-nanocomposite is incorporated on paper matrix, which represents a more suitable choice respect to other substrates for its renewable, biocompatible, biodegradable, and cost-effective properties. Structural and antimicrobial evaluations show that the papers embedded with the SA/ONC-AgNPs possess good mechanical, thermal, barrier and antibacterial properties.

Study of the Effect of Titanium Dioxide Hydrosol on the Photocatalytic and Mechanical Properties of Paper Sheets.

Different amounts of a stable aqueous TiO2 hydrosol were used to fabricate paper sheets having photocatalytic activity. The TiO2 hydrosol was prepared in aqueous medium using titanium butoxide as precursor and acetic acid as catalyst for the hydrolysis of titanium butoxide. An aging process at room temperature and atmospheric pressure was finally applied to obtain crystalline anatase TiO2 hydrosol. The effects of different TiO2 hydrosol loadings on the mechanical strength and barrier properties of modified paper sheets were investigated in detail. The photocatalytic behavior of TiO2-modified paper sheets was investigated as well using methylene blue (MB) as target pollutant.

Dual functional jute fabric biocomposite with chitosan and phosphorylated nano-cellulose (antimicrobial and thermal stability).

In the present study, phosphorylated nanocellulose (P-NC) has been prepared from date palm sheath fibers by a solvent-free acid hydrolysis procedure. Eighteen different treatment procedures were employed for the composite treatment of jute fabric. Different fractions of phosphorylated nanocellulose (1-4%) and chitosan (0.5-2%) were used to examine the effects of treatment procedures on the resulting jute fabric composites. Weight uptake, phosphorus content and tensile properties of the treated jute fabrics have been reported. ATR-FTIR spectroscopy, X-ray diffractometer, transmission electron microscopy, environmental scanning electron microscopy, energy-dispersive X-ray spectroscopy and thermo-gravimetric analysis were used to gain insight into the mechanism of interaction between jute fabric, CS macromolecules, and P-NCs. In addition, the development of antimicrobial and thermal stability properties on jute fabric has been investigated.

Characterization of microcrystalline cellulose prepared from lignocellulosic materials. Part I. Acid catalyzed hydrolysis.

Rice hulls (RH) and bean hulls (BH) were subjected to prehydrolysis treatments, to define the optimum conditions for producing a high percentage of hydrolyzed hemicellulose with a small or moderate degradation of the cellulosic portion. The hydrolysis experiments were performed using hydrochloric and sulfuric acids in concentrations ranging from (0.5 to 5)% (w/w) at 120 degrees C for 90 min and 10% consistency. The effects of different temperatures (80 to 120 degrees C) and time (30 to 120 min) on acid hydrolysis of lignocellulosic materials were recorded. It was found that, the optimum condition to hydrolyze the lignocellulosic materials (RH) and (BH) are 2% (w/w) of mineral acid at 120 degrees C for 90 min and 10% consistency. The cellulose crystallinity index in the different types of lignocellulosic materials with and without acid treatment, were increased from 0.32 to 0.46 in case of RH and from 0.43 to 0.61 in case of BH. Due to the lignin depolymerization during the pretreatment process, the relative absorbency of the methoxyl group and the aromatic rings bands were lowered for the pretreated than the untreated lignocellulosic materials. Also, the band at 1730 cm(-1) which is attributed to carbonyl groups of uronic acids was lowered due the hemicellulose hydrolysis.