Rapid biosynthesis and characterization of metallic gold nanoparticles by olea europea and their potential application in photoelectrocatalytic reduction of 4-nitrophenol.

In recent years, photoelectrocatalysis of gold nanoparticles (Au NPs) has received considerable attention due to their potential to improve catalytic efficiency. Herein, ultra-small Au NPs were successfully synthesized in a single pot using olea europea leaf extract as a green reducing agent for the degradation of 4-nitrophenol. The TEM images showed uniform distribution and spherical shape of Au NPs with an average diameter of 5 nm. Taking advantage of the ability of Au nanoparticles to absorb visible and near-infrared light, 4-nitrophenol can be successfully reduced in the presence of NaBH4. Additionally, the electrochemical activity of the fabricated Au photocathode was investigated by linear sweep voltammetry in the dark and at VIS-NIR light irradiation. This showed an increased photocurrent density of 27 mA cm-2 with an onset potential of -0.71 V. This indicates that the Au photocathode is highly active at VIS-NIR light. Interestingly, the Au photocathode showed a higher current density of 37 mA cm-2 with an onset potential of -0.6 V in the presence of 4-nitrophenol during VIS-NIR irradiation, indicating that 4-nitrophenol was efficiently reduced by the photocathode. The Au photocathode completely reduced 4-nitrophenol in the wastewater within 35 min. Recyclability studies showed that the Au NPs photocathode exhibited higher stability over multiple cycles, confirming the ability of the electrode to treat wastewater over a longer period of time. This study demonstrates the effectiveness of the photoelectrochemical (PEC) process in reducing organic compounds in wastewater.

Nebulised surface-active hybrid nanoparticles of voriconazole for pulmonary Aspergillosis demonstrate clathrin-mediated cellular uptake, improved antifungal efficacy and lung retention.

BACKGROUND: Incidence of pulmonary aspergillosis is rising worldwide, owing to an increased population of immunocompromised patients. Notable potential of the pulmonary route has been witnessed in antifungal delivery due to distinct advantages of direct lung targeting and first-pass evasion. The current research reports biomimetic surface-active lipid-polymer hybrid (LPH) nanoparticles (NPs) of voriconazole, employing lung-specific lipid, i.e., dipalmitoylphosphatidylcholine and natural biodegradable polymer, i.e., chitosan, to augment its pulmonary deposition and retention, following nebulization. RESULTS: The developed nanosystem exhibited a particle size in the range of 228-255 nm and drug entrapment of 45-54.8%. Nebulized microdroplet characterization of NPs dispersion revealed a mean diameter of ≤ 5 µm, corroborating its deep lung deposition potential as determined by next-generation impactor studies. Biophysical interaction of LPH NPs with lipid-monolayers indicated their surface-active potential and ease of intercalation into the pulmonary surfactant membrane at the air-lung interface. Cellular viability and uptake studies demonstrated their cytocompatibility and time-and concentration-dependent uptake in lung-epithelial A549 and Calu-3 cells with clathrin-mediated internalization. Transepithelial electrical resistance experiments established their ability to penetrate tight airway Calu-3 monolayers. Antifungal studies on laboratory strains and clinical isolates depicted their superior efficacy against Aspergillus species. Pharmacokinetic studies revealed nearly 5-, 4- and threefolds enhancement in lung AUC, Tmax, and MRT values, construing significant drug access and retention in lungs. CONCLUSIONS: Nebulized LPH NPs were observed as a promising solution to provide effective and safe therapy for the management of pulmonary aspergillosis infection with improved patient compliance and avoidance of systemic side-effects.

Glutathione Modified Fluorescent CdS QDs Synthesized Using Environmentally Benign Pathway for Detection of Mercury Ions in Aqueous Phase.

An adept, rapid and novel water-soluble glutathione functionalized CdS quantum dots (GSH@CdS QDs) were fabricated using green pathway for sensing of heavy metal contamination prevalent in industrial wastewater. GSH@CdS QDs were facilely synthesized in an aqueous phase reaction and were effectively characterized using FT-IR, XRD, FESEM, HRTEM and EDX techniques. The distinct fluorescence characteristics of GSH@CdS QDs were explored and the QDs showed selective sensitivity towards mercury ions with a low limit of detection of 0.54 nM under optimal conditions. The detailed interaction between GSH@CdS QDs and Hg2+ and the probable fluorescence quenching mechanism were established in this study. In comparison to already reported fluorescent probes, GSH@CdS QDs showed high sensitivity, biocompatibility, long fluorescence stability and convenient removal of mercury ions. Graphical Abstract Facile green route for the fabrication of glutathione capped CdS quantum dots for fluorescence-based detection of toxic Hg2+ ions.

An Efficient and Cost-Effective Nose-Only Inhalational Chamber for Rodents: Design, Optimization and Validation.

The mainstay treatment of pulmonary disorders lies around the direct drug targeting to the lungs using a nebulizer, metered-dose inhaler, or dry powder inhaler. Only few inhalers are available in the market that could be used for inhalational drug delivery in rodents. However, the available rodent inhalers invariably require high cost and maintenance, which limits their use at laboratory scale. The present work, therefore, was undertaken to develop a simple, reliable, and cost-effective nose-only inhalation chamber with holding capacity of three mice at a time. The nebulized air passes directly and continuously from the central chamber to mouthpiece and maintains an aerosol cloud for rodents to inhale. Laser diffraction analysis indicated volume mean diameter of 4.02 ± 0.30 µm, and the next-generation impactor studies, however, revealed mean mass aerodynamic diameter of 3.40 ± 0.27 µm, respectively. An amount of 2.05 ± 0.20 mg of voriconazole (VRC) was available for inhalation at each delivery port of the inhaler. In vivo studies indicated the deposition of 76.12 ± 19.50 µg of VRC in the mice lungs when nebulized for a period of 20 min. Overall, the developed nose-only inhalation chamber offers a reliable means of generating aerosols and successfully exposing mice to nebulization.

Bioremediation of multifarious pollutants using laccase immobilized on magnetized and carbonyldiimidazole-functionalized cellulose nanofibers.

An easily recyclable biocatalyst (Lac@CDI-MCNFs) was synthesized by immobilizing laccase on rice straw-derived carbonyldiimidazole mediated magnetized cellulose nanofibers (MCNFs). Lac@CDI-MCNFs were utilized for bioremediation of cefixime antibiotic (CT), carbofuran pesticide (CF) and safranin O dye (SO) via oxidation-reduction reactions in wastewater. MCNFs provided enhanced pH, temperature and storage stability to laccase and allowed reusability for up to 25 cycles with mere 20 % decline in efficacy. The Lac@CDI-MCNFs effectively degraded 98.2 % CT and 96.8 % CF into benign metabolites within 20 h and completely degraded SO in just 7 h. Response surface modelling (RSM) was employed based on the Box Behnken Design to evaluate the effect of various parameters i.e. pH, catalyst dosage and the pollutants concentration which was further validated with experimental studies. The degradation products were identified using LCMS, which allowed the degradation pathway of the pollutants to be determined. The degradation of all pollutants followed first- order kinetics with rate constants of 0.1775, 0.0832 and 0.958 h-1 and half-life of 3.9, 5.0 and 0.723 h for CT, CF and SO, respectively. Lac@CDI-MCNFs was demonstrated to be an effective catalyst for the degradation of multifarious pollutants.

Highly fluorescent composite of boron nitride quantum dots decorated on cellulose nanofibers for detection and removal of Hg(II) ions from waste water.

To address the challenge of heavy-metal ions in wastewater, boron nitride quantum dots (BNQDs) were synthesized in-situ on rice straw derived cellulose nanofibers (CNFs) as substrate. The composite system exhibited strong hydrophilic-hydrophobic interactions, as corroborated by FTIR, integrated the extraordinary fluorescence properties of BNQDs with fibrous-network of CNFs (BNQD@CNFs) yielding a surface of 35.147 m2 g-1 of luminescent fibers. Morphological studies revealed uniform distribution of BNQDs on CNFs due to hydrogen bonding, according high thermal stability with peak degradation occurring at 347.7 °C and quantum yield of 0.45. The nitrogen-rich surface of BNQD@CNFs exhibited strong affinity for Hg(II), quenching the fluorescence intensity due to combined inner-filter effect and photo-induced electron transfer. The limit of detection (LOD) and limit of quantification (LOQ) were 4.889 nM and 11.1 5 nM, respectively. BNQD@CNFs concomitantly exhibited adsorption of Hg(II) owing to strong electrostatic interactions, confirmed by X-ray photon spectroscopy. Presence of polar BN bonds favoured 96 % removal of Hg(II) at 10 mg L-1 with maximum adsorption capacity of 314.5 mg/ g. Parametric studies corresponded to pseudo-second order kinetics and Langmuir isotherm with R2 ≈ 0.99. BNQD@CNFs exhibited recovery rate between 101.3 %-111 % for real water samples and recyclability upto 5 cycles, demonstrating high potential in wastewater remediation.

Ultra-sensitive detection and scavenging of arsenic ions and ciprofloxacin using 3D multipurpose hemicellulose based aerogel: Adsorption mechanism and RSM optimization.

Trace level detection and efficient removal of arsenite ions (As (III)) and ciprofloxacin (CPR) antibiotic was achieved using hemicellulose based ratiometric fluorescent aerogel. Hemicellulose derived from rice straw was oxidised to dialdehyde hemicellulose followed by crosslinking using chitosan via a Schiff base reaction (C = N) yielding a highly porous 3D fluorescent aerogel (CS@DAHCA). Various factors governing adsorption were analyzed by applying response surface methodology (RSM) approach. CS@DAHCA exhibited ultra-trace level monitoring with the limit of detection of 3.529 pM and 55.2 nM for As (III) and CPR, respectively. The CS@DAHCA showed maximum adsorption capacity of 185 µg g-1 and 454 mg g-1 for As (III) and CPR, respectively. Finally, the feasibility of CS@DAHCA was ascertained for real water samples confirming it as promising candidate for remediation of As (III) and CPR.

Stacking regularization in analogy-based software effort estimation.

Analogy-based estimation (ABE) estimates the effort of the current project based on the information of similar past projects. The solution function of ABE provides the final effort prediction of a new project. Many studies on ABE in the past have provided various solution functions, but its effectiveness can still be enhanced. The present study is an attempt to improve the effort prediction accuracy of ABE by proposing a solution function SABE: Stacking regularization in analogy-based software effort estimation. The core of SABE is stacking, which is a machine learning technique. Stacking is beneficial as it works on multiple models harnessing their capabilities and provides a better estimation accuracy as compared to a single model. The proposed method is validated on four software effort estimation datasets and compared with the already existing solution functions: closet analogy, mean, median and inverse distance weighted mean. The evaluation criteria used are mean magnitude of relative error (MMRE), median magnitude of relative error (MdMRE), prediction (PRED) and standard accuracy (SA). The results suggested that the SABE showed promising performance for almost all the evaluation criteria when compared with the results of the earlier studies.

Amelioration of adsorptive efficacy by synergistic assemblage of functionalized graphene oxide with esterified cellulose nanofibers for mitigation of pharmaceutical waste.

An effort has been undertaken for valorization of surplus biomass to synthesize sustainable and commercially competitive nanoadsorbents utilizing green synthetic strategies. This study encompasses a pioneering research on the comparative adsorption analysis of different modified forms of graphene oxide (GO) combined with functionalized cellulose nanofibers (CNF) derived from surplus biomass for elimination of noxious drug species from aqueous environment with a comprehensive study for evaluating the effect of loading percentage of functionalized GO. Characteristic assessments of the prepared nanocomposites were performed using FT-IR studies, powder XRD studies, FESEM analysis, EDS analysis and BET studies. The prepared nanohybrids were evaluated for their adsorptive performance for elimination of ciprofloxacin and ofloxacin and their performance was optimized in terms of adsorbent loading, pH and initial drug concentration. Further, investigation of adsorbent properties and the adsorption process was undertaken by studying different kinetic and isotherm models of adsorption. The adsorption potential of functionalized CNF was substantially ameliorated through its facile assemblage with functionalized GO. The experimental outcomes revealed that 20 wt% loading of carboxylated graphene oxide within the perforated surface of esterified cellulose nanofibres exhibited best adsorption performance with maximum removal capacity of 45.04 mg g-1 and 85.30 mg g-1 for ciprofloxacin and ofloxacin, respectively. The outstanding regenerability and reusability of nanocomposites present tremendous potential for development of inexpensive and sustainable sorbent materials for managing pharmaceutical pollution. Literature presents scarce data and insufficient number of reports which thoroughly compares the role of differently functionalized GO to potentiate the adsorptive performance of biomass based nanocellulose and its broad application prospects in wastewater remediation. This marks the novelty of the present investigation.

Sensing and annihilation of ultra-trace level arsenic (III) using fluoranthene decorated fluorescent nanofibrous cellulose probe.

Besides presence of heavy metals, especially arsenic in water bodies, northern India is striving to obliterate crop residue, which is otherwise burnt to make the fields ready for subsequent crop, causing acute air pollution. Through this study, an effort has been made to utilize wheat-straw cellulose to develop inexpensive and efficacious sensing cum annihilation system for deleterious arsenite ions As(III) in water by grafting a novel fluorophore, 3-bromofluoranthene on cellulose (BF@CFs). BF@CFs were characterized for structural, morphological and thermal properties using FTIR, XRD, TGA, FESEM, EDS and TEM, which confirmed the successful insertion of fluoranthene molecule on cellulose while preserving its crystalline nanofibrous structure. Fluorescent studies indicated strong affinity of BF@CFs towards arsenite ions exhibiting "turn on" fluorescence response attributed to inhibition of photo induced electron transfer (PET) and metal ion chelation with a limit of detection of 2.8 ng L-1, lower than WHO prescribed limit of 10 µg L-1. Besides sensing, the porous fibrous network of BF@CFs exhibited good adsorption of As(III) ions with maximum adsorption of 171.2 µg g-1 at 35 min under optimized conditions. BF@CFs displayed 95.2% removal efficiency with 2 µg L-1 concentration of As (III) ions at room temperature and neutral pH observed by atomic absorption spectrophotometer coupled with hydride generation assembly (HG-AAS) measurements. BF@CFs retained adsorption 97.3% efficiency after five adsorption/ desorption cycles displaying excellent reusability and stability, strengthening its potential as dual functional sensor and adsorbent.

Unravelling the role of hemp straw derived cellulose in CMC/PVA hydrogel for sustained release of fluoroquinolone antibiotic.

Cellulose fibres derived from hemp stalks, a prevalent biowaste in Northern India, were effectively converted into carboxymethyl cellulose (HS-CMC). Novel environmentally benign hydrogels were synthesized from HS-CMC and polyvinyl alcohol (PVA) using citric acid, a green crosslinker employing freeze-drying method. The HS-CMC/PVA hydrogels were successfully used for sustained release of fluoroquinolone antibiotic, norfloxacin. The hydrogels were characterized using FTIR, XRD, FE-SEM, EDS and thermal stability and evaluated for their carbonyl content, swelling ratio, in-vitro drug release behaviour and bactericidal properties. Successful isolation of cellulose from hemp stalks and its conversion into hydrogel with the presence of ester and carbonyl linkages was confirmed by FTIR. Thermal stability was impaired when cellulose fibres were converted into HS-CMC via carboxymethylation, as the crystalline structure was utterly disrupted. For the hydrogel, the equilibrium swelling ratios at pH -1.2 and 7.4 were assessed as 378.4 % and 538.7 %, respectively, higher than reported CMC hydrogels. The norfloxacin (NFX) encapsulated hydrogels exhibited good bactericidal properties with zone of inhibition of 19.2 ± 0.3 mm against E. coli and 16.4 ± 0.4 mm against S. aureus. The in-vitro release of NFX at pH 1.2 was 91 %, higher than pH 7.4 at 82 % with strong adherence to Higuchi kinetics model signifying that the release of NFX is via dissolution and diffusion. The release kinetics at different pH revealed Fickian behaviour establishing the potential of HS-CMC hydrogel for sustained release of norfloxacin.

Thermal stability of starch bionanocomposites films: Exploring the role of esterified cellulose nanofibers isolated from crop residue.

Thermal stability and degradation kinetics were studied for glycerol plasticized starch (GPS) nanocomposites reinforced with cellulose nanofibers (CNFs) extracted from wheat straw, a crop residue. To assess the effect of surface modifications on CNFs in improving thermal degradation behavior, three types of CNFs were used viz pristine (p-CNFs), esterified (m-CNFs) and a mixture of pristine and esterified (x-CNFs) in equal ratio. Three kinetics models Ozawa-Flynn, Freidman and Kissinger's were used to evaluate activation energy of thermal degradation for pristine and nanocomposite samples. Properties like morphology, crystallinity and water vapor permeability (WVP) were also evaluated. Morphology of m-CNF/GPS bionanocomposites films was superior as compared to other films with better interfacial bonding. Moreover, m-CNFs also exhibited 81 % reduction WVP as compared to pristine GPS films. Activation energy revealed significant enhancement i.e. as high as 52 % in thermal stability with addition of CNFs. Consequent relation between morphology and thermal stability was also established.

Functionalization of nanocellulose to quaternized nanocellulose tri-iodide and its evaluation as an antimicrobial agent.

The reported research involves formation of quaternized nanocellulose triiodide for use as an agent for controlled release of iodine. Nanocellulose was extracted from bagasse and the extracted cellulose nanofibers (CNFs) were quaternized with 3-chloro-2-hydroxypropyltrimethyl ammonium chloride (CHPTAC) in NaOH/urea solution. This was followed by exchange of Cl- with I3- by reaction with KI/I2. Nanofibers having I3- anions were characterized by SEM, TEM, XRD, XRF and FTIR spectroscopy. The iodine content was estimated to be 33.42% and the fibers showed no leaching of molecular I2 in detectable amounts. The fibers showed a maximum activity of 94.73% and 99.86% against E. coli and S. aureus, respectively. These are capable of sustaining 100% antimicrobial activity over a period of six months. These fibers can thus find potential applications as a disinfectant agent in biomedical and water purification processes.

Diamidoximated cellulosic bioadsorbents from hemp stalks for elimination of uranium (VI) and textile waste in aqueous systems.

Selective abolition of hazardous U(VI) ions from nuclear power plants and removal of toxic colorants from textile industries pose great challenge. The work aims to develop cellulosic bioadsorbents from waste stalks of local weed, Cannabis sativa, commonly known as hemp. Cellulose nanofibers (PCFs) were chosen as substrates owing to their unique characteristics like surface hydroxyl groups, large surface to volume ratio and excellent mechanical properties. PCFs were isolated from hemp stalks and their structural characterization using FTIR, TGA and XRD ensured retrieval of pure crystalline cellulose. PCFs were modified via copolymerization to obtain diaminomaleonitrile adorned cellulose grafts (DAMNC) and further converted to get diamidoxime functionalized cellulose (DAOC). DAOC exhibited exceptional affinity with uranium (VI) ions, safranin-o and methylene blue dyes due to presence of two amidoxime groups. Sorption capability was ascertained for optimization of parameters like contact time, pH selectivity, adsorbent dosage and concentration. Sorption followed Pseudo second-order kinetic model with maximum sorption of 220 mg/g, 19.01 mg/g and 46.4 mg/g for U(VI) ions, SO and MB, respectively. EDX mapping revealed uniform adsorption of all the three pollutants on DAOC while XPS ascertained that the sorption originated from multiple interactions between the adsorbent and the pollutants.

Green and novel adsorbent from rice straw extracted cellulose for efficient adsorption of Hg (II) ions in an aqueous medium.

Cellulose nanofibrils (CNF) were extracted from rice straw, a waste lignocellulosic biomass, using soda cooking, which resulted in a reduction of the recalcitrance of biomass, leading to hydrolysis of hemicellulose into sugars, which was subsequently washed, leaving a residue of cellulose. FTIR confirmed the removal of lignin and hemicellulose to yield pure CNF while XRD, DTG and TGA results showed increased crystallinity and thus higher thermal stability. CNFs were functionalized using l-methionine, a natural amino acid, to graft sulfides and amino functional groups onto the surface of fibers. Structural and morphological changes induced by grafting were confirmed by FTIR, XRD, TEM, Mapping and Elemental analysis. Modified fibers exhibited a high adsorption capacity of 131.86 mg/g for Hg (II) ions even at low concentration i.e. 300 ppm owing to sulfides. Optimization of pH on adsorption behavior was established through extensive pH studies and adsorption kinetics. Adsorption follows pseudo second order kinetic model indicating chemisorption for removal of Hg (II) ions from simulated wastewater.

Functionalized magnetic nanomaterials for rapid and effective adsorptive removal of fluoroquinolones: Comprehensive experimental cum computational investigations.

Alarming growth of pharmaceutical residues in aquatic environment has elevated concerns about their potential impact on human health. Taking cognizance of this, the present study is focussed on the coating of cobalt ferrite nanoparticles with different functionalities and to use them as adsorbents for pharmaceutical waste. The thickness of the coating was analysed using Small angle X-ray scattering technique. Thorough study of the isotherms and kinetics were performed suggesting monolayer adsorption and pseudo kinetic order model, respectively. To get an insight of the interactions liable for adsorption of fluoroquinolones over the functionalized magnetic nanoparticles computational studies were undertaken. The results demonstrated substantial evidence proposing remarkable potential of these nanostructures as adsorbents for different pollutants with an additional advantage of stability and facile recoverability with a view to treat wastewater.

Simultaneous extraction of lignin and cellulose nanofibrils from waste jute bags using one pot pre-treatment.

Cellulose nanofibrils and lignin were simultaneously isolated from waste jute bags using soda cooking pretreatment method. Soda cooking resulted in reduction of recalcitrance of lignocellulose biomass leading to hydrolysis of hemicellulose into sugars, which was subsequently washed, leaving a residue of cellulose and lignin.The chemical composition, yield of lignin and cellulose were assessed using TAPPI method and ASTM standards, respectively. Yields of lignin and cellulose were 58 and 45%, respectively, calculated separately on the basis of their content in the jute bags. FTIR results confirmed the removal of lignin and hemicellulose from raw jute fibers during soda cooking process. HNMR results depicted the aromatic structure of lignin which was further confirmed by UV results which clearly indicated the presence of phenolic compounds. The thermal stability of cellulose nanofibrils and lignin was higher than raw jute fibers. SEM showed cylindrical cellulose nanofibrils and agglomerates of amorphous and crystalline region of lignin. Size of jute fibers decreased to 12-18nm whereas the crystallinity increased after chemical and mechanical treatments studied using TEM and XRD, respectively. The study confirmed the isolation of cellulose nanofibrils and lignin extraction discarding the hemicellulose using single pot treatment.

l-Cysteine functionalized bagasse cellulose nanofibers for mercury(II) ions adsorption.

Presence of mercury ions in water, even in trace amounts, is a serious environmental hazard. Hence, there is imperative need to develop innovative and environmentally-friendly materials for their removal from wastewaters. In the present study, cellulose nanofibers (CNFs) extracted from bagasse was esterified with l-cysteine to yield thiol and amine functionalized green material (Cys-CNFs) for removal of Hg2+ ions. The Cys-CNFs were well characterized by SEM, TEM, FTIR, EDS and XRD and evaluated for selective removal of Hg2+ ions from the simulated wastewater. It was observed that Cys-CNFs adsorb Hg2+ ions even at a very low concentration of 1.0mg/L and it exhibited a maximum adsorption capacity of 116.822mgg-1. Kinetic analysis of the data revealed that pseudo-second order kinetics and Langmuir isotherm were followed for adsorption of Hg2+ ions.

Fractionation and physicochemical characterization of lignin from waste jute bags: Effect of process parameters on yield and thermal degradation.

In this work lignin was extracted from waste jute bags using soda cooking method and effect of varying alkali concentration and pH on yield, purity, structure and thermal degradation of lignin were studied. The Lignin yield, chemical composition and purity were assessed using TAPPI method and UV-vis spectroscopy. Yield and purity of lignin ranged from 27 to 58% and 50-94%, respectively for all the samples and was maximum for 8% alkali concentration and at pH 2 giving higher thermal stability. Chemical structure, thermal stability and elementary analysis of lignin were studied using FTIR, HNMR, thermo gravimetric analysis (TGA) and Elemental analyzer. FTIR and HNMR results showed that core structure of lignin starts breaking beyond 10% alkali concentration. S/G ratio shows the dominance of Syringyl unit over guaiacyl unit.

Surface functionalization of nanofibrillated cellulose extracted from wheat straw: Effect of process parameters.

Aggregates of microfibrillated cellulose isolated from wheat straw fibers were subjected to propionylation under different processing conditions of time, temperature and concentration. The treated fibers were then homogenized to obtain surface modified nanofibrillated cellulose. For varying parameters, progress of propionylation and its effects on various characteristics was investigated by FTIR, degree of substitution, elemental analysis, SEM, EDX, TEM, X-ray diffraction, static and dynamic contact angle measurements. Thermal stability of the nanofibrils was also investigated using thermogravimetric technique. FTIR analysis confirmed the propionylation of the hydroxyl groups of the cellulose fibers. The variations in reaction conditions such as time and temperature had shown considerable effect on degree of substitution (DS) and surface contact angle (CA). These characterization results represent the optimizing conditions under which cellulose nanofibrils with hydrophobic characteristics up to contact angle of 120° can be obtained.