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The impact of oral administration of mechanically fibrillated cellulose nanofibers (fib-CNF), a commonly used nanofiber, on toxicity and health remains unclear, despite reports of the safety and beneficial effects of chitin-based nanofibers. Thus, evaluating the oral toxicity of fib-CNF in accordance with OECD Test Guideline 407 (TG407) is essential. This study aimed to assess the safety of orally administered fib-CNF through an acute toxicity study in rats, following the OECD TG407 guidelines for 4 weeks. CNF "BiNFi-s" FMa-10005, derived from mechanically fibrillated pulp cellulose, was administered via gavage to male and female Crl:CD(SD) rats at doses of 50, 150, 500, and 1000 mg/kg/day for 28 days, with a control group receiving water for injection. The study evaluated the toxic effects of repeated administration, and the rats were monitored for an additional 14 days post-administration to assess recovery from any toxic effects. The results showed no mortality in either sex during the administration period, and no toxicological effects related to the test substance were observed in various assessments, including general condition and behavioral function observations, urinalysis, hematological examination, blood biochemical examination, necropsy findings, organ weights, and histopathological examination. Notably, only female rats treated with 1000 mg/kg/day of CNF exhibited a consistent reduction in body weight during the 14-day recovery period after the end of treatment. They also showed a slight decrease in pituitary and liver weights. However, hematological and blood biochemical tests did not reveal significant differences, suggesting a potential weight-suppressive effect of CNF ingestion.

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OBJECTIVES: This laboratory study assessed the performance of a novel fluoride dentifrice containing micro-fibrillated cellulose (MFC) and entrapped silica. METHODS: Removal of extrinsic stains was assessed using the pellicle cleaning ratio (PCR) method, and radioactive dentin abrasivity (RDA) was measured, to calculate a cleaning efficiency index (CEI). Fluoride efficacy was evaluated using widely used remineralization and fluoride uptake methods. The test product (Protegera™) was compared to common dentifrices (Crest - Cavity Protection™ and ProHealth™, Sensodyne Pronamel™, Arm & Hammer™ Advanced Whitening, Crest ProHealth™, and Colgate Optic White™). RESULTS: The PCR for the MFC dentifrice (141) was comparable to three known marketed stain-removing dentifrices (Arm & Hammer™ Advanced Whitening, Crest ProHealth™, and Colgate Optic White™) but it had a significantly lower RDA (88 ± 6) than 5 other products. This gave it the highest CEI of the tested products (2.0). In a 10-day pH cycling study, the fluoride efficacy of the MFC product was comparable to Sensodyne Pronamel and Crest Cavity Protection. The MFC dentifrice was superior for promoting fluoride uptake into incipient enamel lesions compared to the USP reference dentifrice. CONCLUSION: The MFC dentifrice has low abrasion, but despite this, it is highly effective in removing stained pellicle. It also is an efficacious fluoride source when compared to relevant commercially available fluoride dentifrices with high dentin abrasivity. CLINICAL SIGNIFICANCE: The addition of micro-fibrillated cellulose to a fluoride dentifrice gives a low abrasive product that can effectively remove external stains, and serve as an effective fluoride source. This combination of benefits seems well suited to enamel protection and caries prevention.

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An antibacterial nano-hydrogel (ginger essential oil nanoemulsion hydrogel, GEONH) based on Schiff base reaction was prepared using double-formaldehyde micro fibrillated cellulose (DAMFC) and carboxymethyl chitosan (CMCS) loaded with ginger essential oil nanoemulsion (GEON). It was found that when the mass ratio of DAMFC/CMCS/GEON was 1/9/270, the gel time, the water absorbency, gel strength, and morphology were the best. The results of X-ray diffraction and FT-IR confirmed that the aldehyde group on the DAMFC molecular chain formed a stable chemical crosslinking with the amino group on the CMCS molecular chain, resulting in a change in the crystal structure. GEONH showed excellent bactericidal activity against Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. Simultaneously, the prepared GEONH decreased the total viable count, Malondialdehyde, and total sulfhydryl content and improved the taste in the storage of boiled salted duck. Therefore, GEONH film is a promising fresh-keeping packaging for storing meat products. Supplementary Information: The online version contains supplementary material available at 10.1007/s10068-023-01437-4.

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As a cellulose-derived material, nanocellulose possesses unique properties that make it an ideal substrate for various functional composite materials. In this study, we developed a novel composite membrane material capable of adsorbing and photo-catalyzing formaldehyde by immobilizing HKUST-1 (copper open framework composed of 1,3,5-benzenetricarboxylic acid) onto NFC (Nano-fibrillated cellulose) membranes and subsequently loading modified carbon nitride. The synthesized CNx@HN composite membrane (consisting of NFC membrane with anchored HKUST-1 and modified g-C3Nx nanosheets) was thoroughly characterized, and its photocatalytic degradation performance towards low concentrations of formaldehyde (3.0 mg/m3) was investigated. The results demonstrated that HKUST-1's porous nature exhibited a concentrated adsorption capacity for formaldehyde, while the modified CNx (Modified g-C3Nx nanosheets) displayed robust photocatalytic degradation of formaldehyde. The synergistic effect of HKUST-1 and modified CNx on the NFC membrane significantly enhanced the efficiency of formaldehyde degradation. Under xenon lamp irradiation, CNx@HN-5 achieved a total removal efficiency of 86.9 % for formaldehyde, with a photocatalytic degradation efficiency of 48.45 %, showcasing its exceptional ability in both adsorption and photocatalytic degradation of formaldehyde. Furthermore, after 10 cycles of recycling, the composite membrane exhibited excellent stability for the photocatalytic degradation process. Therefore, this study presents a green and facile strategy to fabricate nanocellulose-supported composite membranes with great potential for practical applications in formaldehyde degradation.

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The development of lignocellulosic foams has been gaining momentum due to their sustainability and biodegradability. However, lignocellulosic foams often have low preparation efficiency and poor mechanical properties, especially compression performance. Here, we constructed mechanically robust and thermal insulating cellulosic foams through high-temperature drying, in which all bamboo-sourced lignin-containing pulp fibers (LPF) and steam explosion fibers (SEF) were chosen as a skeleton and high solid fibrillated cellulose (HSFC) as a binder. This study aimed to investigate the effects of the characteristics of bamboo fibers and the HSFC addition on the formation, and mechanical- and thermal insulation performances of the resulting foams. The HSFC incorporation endowed the foams with excellent mechanical performance, the stress at 10 % strain and compressive modulus were 0.29 MPa and 4.4 MPa, respectively, which were 10-fold and 44-fold compared to LPF foam without HSFC. The LPF/HSFC possessed excellent energy absorption capacity (170 kJ/m3 under 40 % strain) as well as good thermal insulating performance (0.054 W/(m·K)). The LPF/HSFC foam with a much more homogeneous cellular structure outperformed the SEF/HSFC foam. This work suggests that the developed bamboo fiber foams hold promise for use in protective packaging and thermal insulation applications.

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The current study presents the synergistic effects of fibrillated cellulose (FC) and nickel-titanium (NiTi) alloy on the performance properties of smart composites. Epoxy resin was reinforced with loadings of 1 %, 3 %, and 5 % FC and 3 % NiTi. The composites were produced using the casting method. The morphological properties have been analyzed using scanning electron microscopy (SEM). For mechanical properties, yield strength, modulus of elasticity, hardness, and impact energy were determined. The corrosion rate was determined via electrochemical corrosion testing. The recovery test was used to measure the shape-memory of the composites. The self-healing of the artificial defect in the composites was observed using a thermal camera. The yield strength, modulus of elasticity, hardness, and impact energy of composites reinforced with 5 % FC and 3 % NiTi increased by 168.2 %, 290 %, 33.3 %, and 114.3 %, respectively, compared to pure epoxy resin. There has been a 56.3 % decrease in the corrosion rate. The percentage of composites that returned from the final state to the original state after a deformation was 4 %. Self-healing analysis revealed that the scratch defect in composites was healed after 24 h. It is concluded that smart composites can be used in the aviation and automotive industries.

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Silica is used as reinforcing filler in the tire industry. Owing to the intensive process of silica production and its high density, substitution with lightweight bio-based micro fibrillated cellulose (MFC) is expected to provide lightweight, sustainable, and highly reinforced tire composite. MFC was modified with oleoyl chloride, and the degree of substitution (DS) was maintained between 0.2 and 0.9. Subsequently, the morphology and crystallinity of the modified MFC were studied and found to be significantly dependent on the DS. The advantages associated with the use of the modified MFC in synergy with silica for the reinforcement of styrene butadiene rubber (SBR) nanocomposite was investigated in comparison with silica/SBR compound. The structural changes occasioned by the DS values influenced the processability, curing kinetics, modulus-rolling resistance tradeoff, and tensile properties of the resultant rubber compounds. We found that the compound made with modified MFC at a DS of 0.67 (MFC16) resulted to the highest reinforcement, with a 350% increase in storage modulus, 180% increase in Young`s modulus, and 15% increase in tensile strength compared to the referenced silica-filled compounds. Our studies show that MFC in combination with silica can be used to reinforce SBR compound for tire tread applications.

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The present Review investigates the interactions between biomaterials and heterocyclic dyes, focusing on their potential application in sustainable wastewater treatment. Heterocyclic dyes are widely used in various industries, resulting in their widespread presence in wastewater, posing environmental challenges. This review explores the utilization of biomaterials as adsorbents for the removal of heterocyclic dyes from contaminated water sources. The interactions between biomaterials, such as cellulose, microfibrilated cellulose and lignin and different heterocyclic dyes are examined through reported experimental analysis and characterization techniques. The study evaluates the adsorption capacity, kinetics, and thermodynamics of the biomaterial-dye systems to elucidate the underlying mechanisms and optimize the treatment process. The review highlight the promising potential of biomaterial-based approaches for sustainable wastewater treatment, providing insights for the development of efficient and environmentally friendly dye removal technologies.

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In this work, a conductive ink based on microfibrillated cellulose (MFC) and multiwalled carbon nanotubes (MWCNTs) was used to produce transducers for rapid liquid identification. The transducers are simple resistive devices that can be easily fabricated by scalable printing techniques. We monitored the electrical response due to the interaction between a given liquid with the carbon nanotube-cellulose film over time. Using principal component analysis of the electrical response, we were able to extract robust data to differentiate between the liquids. We show that the proposed liquid sensor can classify different liquids, including organic solvents (acetone, chloroform, and different alcohols) and is also able to differentiate low concentrations of glycerin in water (10-100 ppm). We have also investigated the influence of two important properties of the liquids, namely dielectric constant and vapor pressure, on the transduction of the MFC-MWCNT sensors. These results were corroborated by independent heat flow measurements (thermogravimetric analysis). The proposed MFC-MWCNT sensor platform may help paving the way to rapid, inexpensive, and robust liquid analysis and identification.

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Tunicate nanocellulose with its unique properties, such as excellent mechanical strength, high crystallinity, and good biodegradability, has potential to be used for the preparation of light management film with tunable transmittance and haze. Herein, we prepared a whole tunicate cellulose film with tunable haze levels, by mixing tunicate microfibrillated cellulose (MFC) and tunicate cellulose nanofibrils (CNF). Then, the obtained whole tunicate cellulose film with updated light management was used to modify the organic solar cell (OSC) substrate, aiming to improve the light utilization efficiency of OSC. Results showed that the dosage of MFC based on the weight of CNF was an important factor to adjust the haze and light transmittance of the prepared cellulose film. When the dosage of MFC was 3 wt.%, the haze of the obtained film increased 74.2% compared to the pure CNF film (39.2%). Moreover, the optimized tunicate cellulose film exhibited excellent mechanical properties (e.g., tensile strength of 168 MPa, toughness of 5.7 MJ/m3) and high thermal stability, which will be beneficial to the workability and durability of OSC. More interestingly, we applied the obtained whole tunicate cellulose film with a high haze (68.3%) and high light transmittance (85.0%) as an additional layer to be adhered to the glass substrate of OSC, and a notable improvement (6.5%) of the power conversion efficiency was achieved. With the use of biodegradable tunicate cellulose, this work provides a simple strategy to enhance light management of the transparent substrate of OSC for improving power conversion efficiency.

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Dentifrice performance in the removal of dental plaque is influenced by the interactions of dentifrice components with tooth surfaces. This randomized controlled clinical study assessed the effectiveness and safety of a novel fluoride dentifrice formulation that included a micro-fibrillated cellulose network with entangled microcrystalline cellulose and silica particles (ProtegeraTM), and compared this to a positive control fluoride dentifrice (Crest Cavity Protection™). Whole mouth dental plaque levels in 82 healthy adults were measured after the first supervised use, and following a week of twice daily use at home. Overall, the test dentifrice was at least three times and up to four times more effective in whole-mouth plaque reductions, with a 38.6% reduction on first use, a 30.9% reduction at day 7, and a 41.6% reduction from day 1 to day 7, compared to reductions of 12.0%, 9.6% and 11.6%, respectively for the positive control, and up to seven times more effective in lingual plaque reductions, than the reference dentifrice (p < 0.001), with a 27.7% reduction on first use, a 22.3% reduction at day 7, and a 31.0% reduction from day 1 to day 7, compared to reductions of 4.4%, 2.2%, and 4.5%, respectively, for the positive control. No safety issues arose from the use of the test dentifrice. These results indicate that including micro-fibrillated cellulose enhances plaque removal effectiveness, without causing adverse changes to oral soft tissues.

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Polysaccharide-based scaffolds are promising carriers for enzyme immobilization. Here, we demonstrate a porous scaffold prepared by direct-ink-writing 3D printing of an ink consisting of nanofibrillated cellulose, carboxymethyl cellulose and citric acid for immobilization application. Negative surface charge introduced by the components made the scaffold amenable for an affinity-like immobilization via the cationic protein module Zbasic2. Zbasic2 fusions of two sugar nucleotide-dependent glycosyltransferases (C-glycosyltransferase, Z-CGT; sucrose synthase, Z-SuSy) were immobilized individually, or co-immobilized, and applied to synthesize the natural C-glycoside nothofagin. The cascade reaction involved ß-C-glycosylation of phloretin (10 mM, ~90 % conversion) from UDP-glucose, provided from sucrose and catalytic amounts of UDP (1.0 mM). Enzymes were co-immobilized at ~65 mg protein/g carrier to receive activities of 9.5 U/g (Z-CGT) and 4.5 U/g (Z-SuSy) in 22-33 % yield (protein) and an effectiveness of 23 % (Z-CGT) and 13 % (Z-SuSy). The scaffold-bound enzymes were recyclable for 5 consecutive reactions.

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Cationic polyacrylamides (CPAMs) are usually used as filler retention agents in papermaking formulations. However, increasing environmental restrictions and their non-renewable origin have driven research into bio-based alternatives. In this context, cationic lignocellulosic derivatives have been attracting considerable research interest as a potential substitute. In this work, distinct cationic celluloses with degrees of substitution of between 0.02 and 1.06 and with distinct morphological properties were synthesized via the cationization of bleached eucalyptus kraft pulp, using a direct cationization with (3-chloro-2-hydroxypropyl) trimethylammonium chloride (CHPTAC) or a two-step cationization, where the cellulose was first oxidized to form dialdehyde cellulose and was then made to react with Girard's reagent T (GT). Fibrillated samples were produced by subjecting some samples to a high-pressure homogenization treatment. The obtained samples were evaluated regarding their potential to flocculate and retain precipitated calcium carbonate (PCC), and their performance was compared to that of a commercial CPAM. The cationic fibrillated celluloses, with a degree of substitution of ca. 0.13-0.16, exhibited the highest flocculation performance of all the cationic celluloses and were able to increase the filler retention from 43% (with no retention agent) to ca. 61-62% (with the addition of 20 mg/g of PCC). Although it was not possible to achieve the performance of CPAM (filler retention of 73% with an addition of 1 mg/g of PCC), the results demonstrated the potential of cationic cellulose derivatives for use as bio-based retention agents.

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The isolation of lignin containing micro- and nanofibrillated cellulose (L-MNFC) requires a multistep process. In this study, beech wood was pre-treated by steam explosion (SE), refined or pre-treated by 3 SE and grinded until gel formation. A conventional cooking in an autoclave (SC) was applied in order to get a control sample. The effect of bleaching of a SE pulp was also studied. The chemical composition of the pulps was assessed as well as fiber morphology to compare the effect of the different processes. Quality index and energy consumption during the production process were studied. Results showed that SE can replace SC for the production of pulps with higher lignin content: 8-12% wt. and 3% wt., respectively. Gels contain micro and nanofibrillated cellulose and residual fibers with a dispersion of lignin nanoparticles and some nanocrystals. Optimization of the ultrafine grinding step was required to minimize the energy consumption.

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The applicability of cellulose nanofibrils (CNFs) has received attention due to their attractive properties. This study proposes the functionalization of açai CNFs with copaiba oil and vegetal tannins to produce films with potential for packaging. Bio-based films were evaluated by vapor permeability, colorimetry, and mechanical strength. CNFs were produced by mechanical fibrillation, from suspensions of bleached açai fibers and commercial eucalipytus pulp. Moreover, copaiba oil and vegetal tannin were added to the CNFs to produce films/nanopapers by casting from both suspensions with concentrations of 1% (based on CNF dry mass). The bulk densities of the eucalyptus CNF films were higher (1.126-1.171 g cm-3) compared to the açai CNF ones. Films from eucalyptus and açai pulps containing copaiba oil and tannins presented higher Tonset and Tmax, respectively (312 and 370 °C). Films with açaí CNFs functionalized with copaiba oil and tannin showed the lowest permeability value (370 g day-1 m-2). Films produced with eucalyptus pulp, and eucalyptus pulp functionalized with copaiba oil highlighted by superior mechanical strength, achieving 133.8 and 121.4 MPa, respectively. The evaluation of colorimetry showed a greater tendency to yellowing for açai films, especially those functionalized with vegetal tannins. Besides the low cost, functionalized vegetal-based nanomaterials could have attractive properties, with potential for application as some kind of packaging, for transporting basic products, such as breads, flours, or products with low moisture content, enabling efficient utilization of forest wastes.

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Herein, a facile strategy was proposed for preparing a high-strength and super-hydrophobic packaging paper with improved moisture and air barrier properties, which was derived from cellulosic pulps, micro-fibrillated cellulose (MFC), and nano-silica (n-SiO2). Owning to the laminated process followed by spraying approach, MFC and n-SiO2 were assembled onto two surfaces of the cellulose paper base, respectively, endowing the mechanical behaviors and superhydrophobic performance of this biodegradable composite papers as packaging material. The as-obtained multilayered papers demonstrated impressive dry tensile strength and remarkable wet tensile strength of 6542.5 N/m and 5875 N/m, which were increased by 56% and 2277%, respectively. In addition, the multilayered paper with rational mechanical properties possessed low permeabilities of air (3.17 × 10-3 µm·Pa-1·s-1), oxygen (9.687 cm3·m-2·day-1·atm), and water vapor (378.24 g·m-2·day-1), respectively, as well as a superhydrophobic performance with the contact angle of ~151.2°. Overall, the feasibility of large-scale production of biodegradable packaging materials in the paper-making industry is demonstrated by the fact that the micro/nanostructures and hydrophobic surfaces could be directly constructed on cellulosic paperboard.

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Micro/nanofibrillated celluloses (M/NFCs) have attracted considerable research interest over the past few decades, with various pretreatments being used to reduce energy consumption and/or increase fibrillation. To date, few studies have considered cationization as a pretreatment for their preparation. In this work, quaternary ammonium groups were attached to cellulose fibers by a direct reaction with 2,3-epoxypropyltrimethylammonium chloride or by a two-step method (periodate oxidation + Girard's reagent T). The cationic fibers with degrees of substitution (DS) between 0.02 and 0.36, were subjected to homogenization treatment. The morphological properties, chemical composition, and rheological behavior were evaluated to assess the effect of DS and the effect of the cationization method (for samples with similar DS). The two-step cationization resulted in significant degradation of the cellulose structure, leading to the formation of short fibrils and solubilization of the material, ranging from 6% to almost complete solubilization at a DS of 0.36. Direct cationization resulted in longer fibrils with an average diameter of 1 µm, and no significant cellulose degradation was observed, leading to a more cohesive gel-like material (at 1 wt%). These observations clearly show the strong influence of the cationization method on the final properties of the cationic cellulosic materials.

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Construction of monolithic cryogels that can efficiently adsorb proteins is of great significance in biotechnological and pharmaceutical industries. Herein, a novel approach is presented to fabricate microfibrillated cellulose (MFC)/sodium alginate (SA) cryogels by using freezing-induced oxa-Michael reaction at -12 °C. Thanks to the controllable reactiveness of divinyl sulfone (DVS), cryo-concentrated pH increase activates the oxa-Michael reaction between DVS and hydroxyl groups of MFCs and SAs. The obtained composite cryogel exhibits outstanding underwater shape recovery and excellent fatigue resistance. Moreover, the MFC/SAs reveal a high lysozyme adsorption capacity of 294.12 mg/g, surpassing most of absorbent materials previously reported. Furthermore, the cryogel-packed column can purify lysozyme continuously from chicken egg white, highlighting its outstanding practical application performance. Reuse experiments indicated that over 90% of lysozyme extraction capacity was retained after 6 cycles. This work provides a new avenue to design and develop next-generation chromatographic media of natural polysaccharide-based cryogel for protein purification.

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The tendency to use cellulose fibrils for direct ink writing (DIW) of three-dimensional (3D) printing has been growing extensively due to their advantageous mechanical properties. However, retaining cellulose in its fibrillated forms after the printing process has always been a challenge. In this study, cellulose macrofibrils (CMFs) from oil palm empty fruit bunch (OPEFB) fibers were partially dissolved for consistent viscosity needed for DIW 3D printing. The printed CMF structure obtained from optimized printing profiles (volumetric flow rate, Qv = 9.58 mm/s; print speed, v = 20 mm/s), exhibited excellent mechanical properties (tensile strength of 66 MPa, Young's modulus of 2.16 GPa, and elongation of 8.76%). The remarkable structural and morphological effects of the intact cellulose fibrils show a homogeneous distribution with synthesized precipitated calcium carbonate (CaCO3) nanoparticles. The shear-aligned CMF/CaCO3 printed composite exhibited a sustained therapeutic drug release profile that can reduce rapid release that has adverse effects on healthy cells. In comparison with the initial burst release of 5-fluorouracil (5-FU) by CaCO3, the controlled release of 5-fluorouracil can be varied (48 to 75%) with the composition of CMF/CaCO3 allowing efficient release over time.

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Nano-fibrillated cellulose (NFC) was extracted by a chemical method involving alkali and acid hydrolysis. The characterisation of the citrus sinensis fruit peel bran and nano-fibrillated cellulose was performed by XRD, FTIR, TEM, and FESEM. XRD confirmed the phase of NFC which showed monoclinic crystal with spherical to rod shape morphology with a size of 44-50 nm. The crystallinity index of treated NFC increased from 39% to 75%. FTIR showed the removal of lignin and hemicellulose from waste peels due to the alkaline treatment. Silver nanoparticles were also synthesised by utilizing extract of citrus sinensis skins as a reducing agent. Pharmaceutical effluent samples from an industrial area were tested by Atomic Absorption Spectrometry. Out of the four metals obtained, cadmium and chromium were remediated by silver nanoparticles with nano-fibrillated cellulose via simulated method in 100 mg/L metal-salt concentrations over a time period of 160 min. The highest removal efficiency was found for cadmium, i.e., 83%, by using silver and NFC together as adsorbents. The second highest was for chromium, i.e., 47%, but by using only NFC. The Langmuir and Freundlich isotherms were well fitted for the sorption of Cd (II) and Cr (II) with suitable high R2 values during kinetic simulation. Thus, the isolation of NFC and synthesis of silver nanoparticles proved efficient for heavy metal sorption by the reuse of waste skins.