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The current study concerns the valorization of waste rice hulls into value-added materials. To achieve this goal, first, the extraction route of mesoporous silica nanoparticles (SiO2NPs) from rice hulls using citric acid as a carbon template was compared with that prepared by conventional methods of incineration only. Both routes were performed at different temperatures of 600 and 700°C, and the fabricated SiO2NPs were studied by N2 physisorption isotherm, X-ray diffraction (XRD), Fourier transform infrared (FTIR), dynamic light scattering (DLS), and thermogravimetric (TG) analyses. The results show the influence of both routes and temperature on the porous structure, surface area, and charge of as-fabricated SiO2NPs. Furthermore, the physico-chemical features of as-prepared mesoporous SiO2NPs were utilized, in a facile and green way, to prepare silver NPs with high anti-microbial activity. The results were validated by the tools of UV-visible, FTIR, XRD, and XPS spectroscopy. Finally, the fabricated silver-doped mesoporous SiO2NPs were used as auxiliary additives through one-pot printing of different types of fabric (i.e., polyester (synthetic fabric), cotton (natural fabric), and cotton/polyester (blended fabric)). The EDX mapping of the pigment-printed fabrics with Ag-doped SiO2NPs exhibited the homogeneous distribution of Ag and Si atoms together with C and O throughout the fabric matrix. Interestingly, the pigment-printed fabrics with Ag-doped SiO2NPs demonstrated superior antibacterial activity, ultraviolet protection factor (UPF), and color characteristics in comparison to the conventional dyeing component. [ABSTRACT FROM AUTHOR]

The transformation of agro-waste into biochar using thermochemical processes aids in the management and disposal of biomass with the potential to provide significant energy. Different biochars exhibit different characteristics and performances depending on the fabrication method employed. Besides, many applications, such as remediation to adsorb heavy metals which favor biochars rich with oxygen-containing functional groups on their surface. Therefore, this study deals with the catalytic carbonization of the rachis part in windmill palm trees with ferrocene at different temperatures (300, 350, 450, and 500 °C), time intervals (25, 40, and 90 min.), and ratios (3:1, 3:2, and 3:3 palm tree: ferrocene ratio) to produce oxidized nanobiochar. The highest electronegativity's (− 61.8 and − 64 mV) for PTONB were observed when samples were prepared at 350 °C, 90 min., 3:1 PT: F and 350 °C, 25 min., 3:2 PT: F, respectively. Morphological analysis showed that, the carbonization of windmill palm tree at 350 °C, 90 min. without ferrocene give spherical nano-biochar with bulky particle size of 237 nm. However, after ferrocene treatment, the nanobiochar particle size was reduced, ranging from 87 to 3 nm. Thus, the ferrocene/palm tree catalytic carbonization process is highly relevant to decreasing particle sizes. Consequently, based on the findings from physicochemical analyses (e.g., SEM-EDX, ATR-FTIR, X-ray diffraction, and high-resolution TEM), a straightforward and rapid method to synthesize an oxidized nano-biochar, with a wide variety of structural characterizations, at a low temperature in a single step under a muffled atmosphere has been developed. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

In this study, flat sheet submerged MBR (FS‐SMBR) was investigated under 6 and 4 h hydraulic retention times (HRT) and 40 days solid retention time with real municipal wastewater. The implementation of the treatment system was evaluated in terms of physico‐chemical and microbial analysis as well as sludge characterization. The permeate of FS‐SMBR complied with the standards for reuse and non‐detectable levels of faecal coliform was achieved at 6 and 4 h HRTs, with pore‐blocking resistances (Rt) of 28 × 1011 and 40 × 1011/m, respectively. Examining another dominant factor, that is, sludge viscosity, the best results were acquired using HRT 4 h for domestic wastewater. Furthermore, the results obtained were validated and calibrated using the GPS‐X software simulator, and the results of modelled data were completely matched with the experimental data under the same conditions. [ABSTRACT FROM AUTHOR]

The provision of potable drinking water is of public health concern, especially in developing countries. This study aimed to test the bacteriological quality of well water in El-Qalubia governorate, Egypt. Untreated well water samples were collected from thirteen sites all over the governorate. The most probable number of tests (presumptive and confirmed tests) revealed that water is unpotable for drinking. Five pathogenic microorganisms were isolated from samples. These isolates were identified by biochemical and phytic tests as Klebsiella Pneumonia, Enterobacter sp., Pseudomonas aeruginosa, Citrobacter braaki, and E. coli. Antibiotic susceptibility test for these isolates confirmed their multidrug resistance. Thus, this study has shown a high level of bacterial contamination in all the samples. Hence, the need for good maintenance and hygienic practices by households to reduce the risk of disease outbreaks from the organisms encountered in this study. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

In this study we have recycled two types of waste papers, newspapers and magazines, to prepare paperboard sheets for multipurpose applications. The recycling procedure succeeded in removing most of inorganic contaminants via de-inking process. To enhance the flame retardant ability of paperboard sheets, treatment with varying concentrations (1, 3 and 5 % wt/vol) of organophosphorus-silane compound in the absence and presence of starch (0.2 % wt/vol) was done. The thermal proofing properties of paperboard sheets have been modified after treatment with organophosphorus-silane compound and starch/organophosphorus-silane biocomposite. The results showed that, 3 % (wt/vol) was the minimum concentration to accomplish fire retardancy of paperboard sheets. The addition of starch to the organophosphorus-silane compound enhances the physicomechanical properties of modified paperboard sheets. The paperboard sheets treated organophosphorus-silane compound and starch/organophosphorus-silane biocomposite showed dissimilar activities against Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. Various analyses were performed to study the physical, chemical, mechanical and thermal properties of the prepared paperboard sheets. [ABSTRACT FROM AUTHOR]

Herein we present facile and green two-steps method for the fabrication of silver-carboxylated nanocellulose (Ag-ONCs) nanocomposite. Respecting the Circular Economy principle, the ONCs are prepared starting from the treatment of agriculture bagasse waste with ammonium persulfate—APS. This method permits to obtain ONCs fibers with rod or whisker shapes, with size and length in the range 6–10 nm and 90–150 nm, respectively. Ag-ONCs are then fabricated using a green photochemical approach. The UV irradiation works as radical initiator for the silver reduction, in water solution and at room temperature. The ONCs act as a template and reducing agent for silver nanoparticles formation, due to the specific hydroxyl and carboxyl groups on the cellulose surface. The structural and morphological properties of ONCs and Ag-ONCs nanocomposite are well evaluated by FT-IR, XRD, UV–Vis, AFM, SEM and TEM characterizations. The results showed that well crystalline, quasi-spherical silver nanoparticles of about 4–10 nm dispersed in the ONCs matrix are fabricated. Qualitative antibacterial tests towards gram negative (Escherichia coli and Pseudomonas aeruginosa) and gram positive (Staphylococcus aureus and Bacillus subtilis) bacteria are carried out and the results demonstrated that the Ag-ONCs inhibit the bacteria growth, with 12–14 mm of inhibition zone for both the bacteria groups. Also, quantitative antibacterial tests for E. coli, chosen as representative for its diffusion, are carried out and the bacteria growth rate and the inhibition rate for Ag-ONCs at different concentrations are evaluated. The analysis showed that the MIC (minimum inhibition concentration) for Ag is about 110 µg/mL for E. coli. These results demonstrated that the Ag-ONCs possess suitable and promising antibacterial behavior and could be used for industrial and technological application. [ABSTRACT FROM AUTHOR]