Facile synthesis of TiO2/CNC nanocomposites for enhanced Cr(VI) photoreduction: Synergistic roles of cellulose nanocrystals

Urea-driven g-C3N4 nanostructures for highly efficient photoreduction of Cr(vi) under visible LED light: effects of calcination temperature

Graphitic carbon nitride (g-C3N4) nanostructures were synthesized via the calcination of urea at various temperatures ranging between 400 and 600 °C and were utilized for photoreduction of Cr(vi) in aqueous medium. Due to the low adsorption of Cr(vi) on the g-C3N4 surface, a more accurate assessment of the photocatalytic performance of the samples was carried out. Although the characterization showed that the specific surface of samples increased as the calcination temperature increased, the most efficient product in terms of the photoreduction duration of Cr(vi) was produced through the calcination process carried out at 450 °C, which reduced the concentration by more than 99% in 40 minutes. These results demonstrate that the structural and surface properties of g-C3N4 are critical factors that impact the photocatalytic performance. Alongside the calcination temperatures, the concentration of citric acid as a hole scavenger, the source of illumination, pH levels, and the recycling ability of the produced specimen at 450 °C were also investigated. Conspicuously, the photocatalyst works better when more citric acid is present and the pH level decreases. Out of all the cases studied regarding the light source, the 400 nm LED light source was found to be the most efficient. Additionally, even after going through the photoreduction process four times, the photocatalyst still remained highly efficient.

TiO2 Films with Macroscopic Chiral Nematic-Like Structure Stabilized by Copper Promoting Light-Harvesting Capability for Hydrogen Generation

Cellulose nanocrystals (CNCs) have inspired the synthesis of various advanced nanomaterials, opening opportunities for different applications. However, a simple and robust approach for transferring the long-range chiral nematic nanostructures into TiO2 photocatalyst is still fancy. Herein, a successful fabrication of freestanding TiO2 films maintaining their macroscopic chiral nematic structures after removing the CNCs biotemplate is reported. It is demonstrated that including copper acetate in the sol avoids the epitaxial growth of the lamellar-like structure of TiO2 and stabilizes the chiral nematic structure instead. The experimental results and optical simulation demonstrate an enhancement at the blue and red edges of the Fabry-Pérot reflectance peak located in the visible range. This enhancement arises from the light scattering effect induced by the formation of the chiral nematic structure. The nanostructured films showed 5.3 times higher performance in the photocatalytic hydrogen generation, compared to lamellar TiO2, and benefited from the presence of copper species for charge carriers' separation. This work is therefore anticipated to provide a simple approach for the design of chiral nematic photocatalysts and also offers insights into the electron transfer mechanisms on TiO2/CuxO with variable oxidation states for photocatalytic hydrogen generation.

Tailoring visible-light active TiO2/cellulose nanocomposites with controlled crystalline structure for enhanced photocatalytic performance

This work involves a green and simple synthesis of TiO2 nanoparticles on cellulose under mild conditions without the need for calcination via hydrolysis of titanium oxysulfate (TiOSO4). The synthesis conditions, such as sulfuric acid concentration (0-10% wt), temperature (70-90 ℃), and time (4-8 h), focused on precisely controlling the structure of TiO2 to enhance its photocatalytic effectiveness under visible light. At a lower 2.5 wt% sulfuric acid concentration, pure anatase was formed on the cellulose, while an increase in the range of 5.0-7.5 wt% sulfuric acid concentration yielded a rutile phase, resulting in a mixed phase of anatase and rutile on the cellulose. The pure rutile phase was found at a low temperature (70 ℃), while increased temperature led to the formation of the anatase phase. These results confirmed that the formation of crystalline TiO2 phase on the cellulose depended on sulfuric acid concentration and temperature for hydrolysis. Additionally, the photocatalytic properties of the obtained materials were evaluated by degradationvisible of Rhodamine B (RhB) under UV and visible light. The findings revealed that the mixed phase (anatase/rutile) of TiO2 on the cellulose demonstrated a superior photocatalytic efficiency (99.2%) compared to pure anatase (85.75%) and rutile (75.08%) when exposed to visible light.

Microtubular cellulose-derived kapok fibre as a solid electron donor for boosting photocatalytic H2O2 production over C-doped g-C3N4 hybrid complexation

Cellulose continues to play an important and emerging role in photocatalysis, and its favourable properties, such as electron-rich hydroxyl groups, could enhance the performance of photocatalytic reactions. For the first time, this study exploited the kapok fibre with microtubular structure (t-KF) as a solid electron donor to enhance the photocatalytic activity of C-doped g-C₃N₄ (CCN) via ligand-to-metal-charge-transfer (LMCT) to improve hydrogen peroxide (H₂O₂) production performance. As confirmed by various characterisation techniques, the hybrid complex consisting of CCN grafted on t-KF was successfully developed in the presence of succinic acid (SA) as a cross-linker via a simple hydrothermal approach. The complexation formation between CCN and t-KF results in the CCN-SA/t-KF sample displaying a higher photocatalytic activity than pristine g-C₃N₄ to produce H₂O₂ under visible light irradiation. The enhanced physicochemical and optoelectronic properties of CCN-SA/t-KF imply that the LMCT mechanism is crucial in improving photocatalytic activity. This study promotes utilising the unique t-KF material's properties to develop a low-cost and high-performance cellulose-based LMCT photocatalyst.

Visible-Light-Driven Photocatalytic Dehydrogenation of Alcohols on TiO2 via Ligand-to-Metal Charge Transfer for Coproduction of H2 and Aldehydes

Developing visible-light-driven photocatalysts for the catalytic dehydrogenation of organics is of great significance for sustainable solar energy utilization. Here, we first report that aromatic alcohols could be efficiently split into H₂ and aldehydes over TiO₂ under visible-light irradiation through a ligand-to-metal charge transfer (LMCT) mechanism. A series of TiO₂ catalysts with different surface contents of the hydroxyl group (-OH) have been synthesized by controlling the hydrothermal and calcination synthesis methods. An optimal H₂ production rate of 18.6 μmol h^-1 is obtained on TiO₂ synthesized from the hydrothermal method with a high content of surface -OH. Experimental characterizations and comparison studies reveal that the surface -OH markedly influences the formation of LMCT complexes and thus changes the visible-light-driven photocatalytic performance. This work is anticipated to inspire further research endeavors in the design and fabrication of visible-light-driven photocatalyst systems based on the LMCT mechanism to realize the simultaneous synthesis of clean fuel and fine chemicals.

Simultaneous photocatalytic removal of organic dye and heavy metal from textile wastewater over N-doped TiO2 on reduced graphene oxide

Methylene blue (MB) and hexavalent chromium Cr(VI) are hazardous pollutants in textile waste and cannot be completely removed using conventional methods. So far, there have been no specific studies examining the synthesis and activity of N-TiO₂/rGO as a photocatalyst for removing MB and Cr(VI) from textile wastewater. This work especially highlights the synthesis of N-TiO₂/rGO as a photocatalyst which exhibits a wider range of light absorption and is highly effective for simultaneous removal of MB-Cr(VI) under visible light. Titanium tetrachloride (TiCl₄) was used as the precursor for N-TiO₂ synthesis using the sol-gel method. Graphite was oxidized using Hummer's method and reduced with hydrazine to produce rGO. N-TiO₂/rGO was synthesized using a hydrothermal process and then analyzed using several characterization instruments. The X-ray diffraction pattern (XRD) showed that the anatase N-TiO₂/rGO phase was detected at the diffraction peak of 2θ = 25.60°. Scanning electron microscopy and transmission electron microscopy (SEM-EDS and TEM) dispersive X-ray spectrometry images show that N-TiO₂ particles adhere to the surface of rGO with uniform size and N and Ti elements are present in the N-TiO₂/rGO combined investigated. Gas absorption analysis data (GSA) shows that N-TiO₂/rGO had a surface area of 77.449 m²/g, a pore volume of 0.335 cc/g, and a pore size of 8.655 nm. The thermogravimetric differential thermal analysis (TG-DTA) curve showed the anatase phase at 500-780 °C with a weight loss of 0.85%. The N-TiO₂/rGO composite showed a good photocatalyst application. The photocatalytic activity of N-TiO₂/rGO for textile wastewater treatment under visible light showed higher effectiveness than ultraviolet light, with 97.92% for MB and 97.48% for Cr(VI). Combining N-TiO₂ with rGO is proven to increase the light coverage in the visible light region. Removal of MB and Cr(VI) can be carried out simultaneously and results in a removal efficiency of 95.96%.

Photoreduction of Cr(VI) by TiO2 adsorbed gold nanoparticles and perylene as a novel organic-inorganic hybrid photocatalyst

The photoreduction of hexavalent chromium (Cr(VI)) using TiO₂ adsorbed gold nanoparticles and perylene (Au/Pe/TiO₂) as a novel organic-inorganic hybrid photocatalyst has been studied. The irradiation by a Xe lamp of a Cr (VI) aqueous solution (0.1 mM) with the Au/Pe/TiO₂ powder resulted in the reduction of the Cr(VI). The rate of Cr(VI) reduction reached 98.3% by the irradiation for 60 min. The reaction rate constant using Au/Pe/TiO₂ (0.0545 min^-1) was higher than that of TiO₂ (0.0218 min^-1), Pe/TiO₂ (0.0303 min^-1), or Au/TiO₂ (0.0393 min^-1). Gold nanoparticles and perylene synergistically accelerated the TiO₂ photocatalytic reaction. This result is due to the Z-scheme electron transfer between Pe and TiO₂ and the suppression of charge recombination by the gold nanoparticles. The irradiation of sunlight also led to the photocatalytic reduction of the Cr(VI) by Au/Pe/TiO₂. In addition, successive reduction of the Cr(VI) was achieved by using a column packed with the Au/Pe/TiO₂ powder immobilized by calcium alginate gel.

Cellulose: A Review of Water Interactions, Applications in Composites, and Water Treatment

Cellulose is known to interact well with water, but is insoluble in it. Many polysaccharides such as cellulose are known to have significant hydrogen bond networks joining the molecular chains, and yet they are recalcitrant to aqueous solvents. This review charts the interaction of cellulose with water but with emphasis on the formation of both natural and synthetic fiber composites. Covering studies concerning the interaction of water with wood, the biosynthesis of cellulose in the cell wall, to its dispersion in aqueous suspensions and ultimately in water filtration and fiber-based composite materials this review explores water-cellulose interactions and how they can be exploited for synthetic and natural composites. The suggestion that cellulose is amphiphilic is critically reviewed, with relevance to its processing. Building on this, progress made in using various charged and modified forms of nanocellulose to stabilize oil-water emulsions is addressed. The role of water in the aqueous formation of chiral nematic liquid crystals, and subsequently when dried into composite films is covered. The review will also address the use of cellulose as an aid to water filtration as one area where interactions can be used effectively to prosper human life.

Recent advances in cellulose supported photocatalysis for pollutant mitigation: A review

In recent times, green chemistry or "green world" is a new and effective approach for sustainable environmental remediation. Among all biomaterials, cellulose is a vital material in research and green chemistry. Cellulose is the most commonly used natural biopolymer because of its distinctive and exceptional properties such as reproducibility, cost-effectiveness, biocompatibility, biodegradability, and universality. Generally, coupling cellulose with other nanocomposite materials enhances the properties like porosity and specific surface area. The polymer is environment-friendly, bioresorbable, and sustainable which not only justifies the requirements of a good photocatalyst but boosts the adsorption ability and degradation efficiency of the nanocomposite. Hence, knowing the role of cellulose to enhance photocatalytic activity, the present review is focused on the properties of cellulose and its application in antibiotics, textile dyes, phenol and Cr(VI) reduction, and degradation. The work also highlighted the degradation mechanism of cellulose-based photocatalysts, confirming cellulose's role as a support material to act as a sink and electron mediator, suppressing the charge carrier's recombination rate and enhancing the charge migration ability. The review also covers the latest progressions, leanings, and challenges of cellulose biomaterials-based nanocomposites in the photocatalysis field.

Photocatalytic and antibacterial activity of graphene oxide/cellulose-doped TiO2 quantum dots: in silico molecular docking studies

Graphene oxide (GO) and cellulose nanocrystal (CNC)-doped TiO₂ quantum dots (QDs) were effectively synthesized by employing the co-precipitation method for the degradation of dyes and antimicrobial applications. A series of characterizations, i.e., XRD, FTIR, UV-visible spectroscopy, EDS, FE-SEM, and HR-TEM, was used to characterize the prepared samples. A reduction in PL intensity was observed, while the band gap energy (E _g) decreased from 3.22 to 2.96 eV upon the incorporation of GO/CNC in TiO₂. In the Raman spectra, the D and G bands were detected, indicating the presence of graphene oxide in the composites. Upon doping, the crystallinity of TiO₂ increased. HR-TEM was employed to estimate the interlayer d-spacing of the nanocomposites, which matched well with the XRD data. The photocatalytic potential of the prepared samples was tested against methylene blue, methylene violet, and ciprofloxacin (MB:MV:CF) when exposed to visible light for a certain period. The antibacterial activity of GO/CNC/TiO₂ QDs against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) bacteria in vitro was tested to determine their potential for medicinal applications. The molecular docking investigations of CNC-TiO₂ and GO/CNC-doped TiO₂ against DNA gyrase and FabI from E. coli and S. aureus were found to be consistent with the results of the in vitro bactericidal activity test. We believe that the prepared nanocomposites will be highly efficient for wastewater treatment and antimicrobial activities.

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.

Pt-Chitosan-TiO2 for Efficient Photocatalytic Hydrogen Evolution via Ligand-to-Metal Charge Transfer Mechanism under Visible Light

The Pt-chitosan-TiO2 charge transfer (CT) complex was synthesized via the sol-gel and impregnation method. The synthesized photocatalysts were thoroughly characterized, and their photocatalytic activity were evaluated toward H2 production through water reduction under visible-light irradiation. The effect of the preparation conditions of the photocatalysts (the degree of deacetylation of chitosan, addition amount of chitosan, and calcination temperature) on the photocatalytic activity was discussed. The optimal Pt-10%DD75-T200 showed a H2 generation rate of 280.4 μmol within 3 h. The remarkable visible-light photocatalytic activity of Pt-chitosan-TiO2 was due to the CT complex formation between chitosan and TiO2, which extended the visible-light absorption and induced the ligand-to-metal charge transfer (LMCT). The photocatalytic mechanism of Pt-chitosan-TiO2 was also investigated. This paper outlines a new and facile pathway for designing novel visible-light-driven photocatalysts that are based on TiO2 modified by polysaccharide biomass wastes that are widely found in nature.

Flexible Humidity Sensors Based on Multidimensional Titanium Dioxide/Cellulose Nanocrystals Composite Film

A humidity sensor is a crucial device in daily life; therefore, in the present study, a novel humidity sensor was designed to increase its specific surface area to improve its humid sensing capacity and conductivity. Titanium dioxide nanoparticles (TiNP) consisting of zero-dimensional nanospheres and one-dimensional nanotubes were prepared by anodic oxidation. Rod-shaped cellulose nanocrystals (CNCs) with average length and diameter of 60 nm and 800 nm, respectively, were obtained by enzymatic hydrolysis and high pressure homogenization. TiNP/CNC composite films exhibited superior hydrophilicity and large specific surface areas based on Fourier transform infrared spectroscopy and nitrogen adsorption-desorption results. The humidity sensing characteristics of sensors based on TiNP/CNC flexible composite films with varying contents of TiNP were investigated under a relative humidity range of 11-97%. The 6% TiNP/CNC-based humidity sensor exhibited high humidity response, rapid response/recovery speed, and high stability. Furthermore, the humidity sensing mechanism of TiNP/CNC composite films was analyzed based on the density functional theory. TiNP/CNC-based humidity sensors could be applied in flexible and wearable electronics.

Experimental and Computational Study of Zr and CNC-Doped MnO2 Nanorods for Photocatalytic and Antibacterial Activity

Cellulose nanocrystals (CNC), MnO₂, CNC-doped MnO₂, and Zr/CNC-doped MnO₂ were prepared with a hydrothermal method to assess their photocatalytic and antibacterial properties. Various characterizations were undertaken to determine the phase composition, the existence of functional units, optical characteristics, elemental analysis, surface topography, and microstructure of the prepared materials. Sample crystallinity was improved, whereas a decrease in crystallite size was observed with increasing amounts of dopants. Incorporation of dopants (CNC and Zr) into MnO₂ instigated a transformation in morphology from nanoclusters to nanorods with different diameters. Furthermore, photocatalytic activity experiments indicated a more effective degradation of methylene blue (MB) dye with CNC-doped MnO₂ and Zr/CNC-codoped MnO₂ while enhancing the bacterial efficacy for both G +ve and G -ve. Density functional theory was utilized to model the structures and elucidate their bonding and charge transfer mechanisms. The Zr/CNC-MnO₂ system showed charge depletion around Mn atoms, while charges were observed to accumulate around oxygen atoms.

Two-Dimensional Titanium Dioxide-Surfactant Photoactive Supramolecular Networks: Synthesis, Properties, and Applications for the Conversion of Light Energy

The desire to harness solar energy to address current global environmental problems led us to investigate two-dimensional (2D) core-shell hybrid photocatalysts in the form of a 2D-TiO2-surfactant, mainly composed of fatty acids. The bulk products, prepared by two slightly different methods, consist of stacked host-guest hybrid sheets held together by van der Waals forces between alkyl carboxylate moieties, favoring the synergistic conjugation of the photophysical properties of the core and the hydrophobicity of the self-assembled surfactant monolayer of the shell. X-ray diffraction and the vibrational characteristics of the products revealed the influence of synthesis strategies on two types of supramolecular aggregates that differ in the core chemical structure, guest conformers of alkyl surfactant tails and type, and the bilayer and monolayer of the structure of nanocomposites. The singular ability of the TiO2 core to anchor carboxylate leads to commensurate hybrids, in contrast to both layered clay and layered double-hydroxide-based ion exchangers which have been previously reported, making them potentially interesting for modeling the role of fatty acids and lipids in bio-systems. The optical properties and photocatalytic activity of the products, mainly in composites with smaller bandgap semiconductors, are qualitatively similar to those of nanostructured TiO2 but improve their photoresponse due to bandgap shifts and the extreme aspect-ratio characteristics of two-dimensional TiO2 confinement. These results could be seen as a proof-of-concept of the potential of these materials to create custom-designed 2D-TiO2-surfactant supramolecular photocatalysts.

Nanocellulose for Sustainable Water Purification

Nanocelluloses (NC) are nature-based sustainable biomaterials, which not only possess cellulosic properties but also have the important hallmarks of nanomaterials, such as large surface area, versatile reactive sites or functionalities, and scaffolding stability to host inorganic nanoparticles. This class of nanomaterials offers new opportunities for a broad spectrum of applications for clean water production that were once thought impractical. This Review covers substantial discussions based on evaluative judgments of the recent literature and technical advancements in the fields of coagulation/flocculation, adsorption, photocatalysis, and membrane filtration for water decontamination through proper understanding of fundamental knowledge of NC, such as purity, crystallinity, surface chemistry and charge, suspension rheology, morphology, mechanical properties, and film stability. To supplement these, discussions on low-cost and scalable NC extraction, new characterizations including solution small-angle X-ray scattering evaluation, and structure-property relationships of NC are also reviewed. Identifying knowledge gaps and drawing perspectives could generate guidance to overcome uncertainties associated with the adaptation of NC-enabled water purification technologies. Furthermore, the topics of simultaneous removal of multipollutants disposal and proper handling of post/spent NC are discussed. We believe NC-enabled remediation nanomaterials can be integrated into a broad range of water treatments, greatly improving the cost-effectiveness and sustainability of water purification.

Process enhancing strategies for the reduction of Cr(VI) to Cr(III) via photocatalytic pathway

This discourse aimed at providing insight into the strategies that can be adopted to boost the process of photoreduction of Cr(VI) to Cr(III). Cr(VI) is amongst the highly detestable pollutants; thus, its removal or reduction to an innocuous and more tolerable Cr(III) has been the focus. The high promise of photocatalysis hinged on the sustainability, low cost, simplicity, and zero sludge generation. Consequently, the present dissertation provided a comprehensive review of the process enhancement procedures that have been reported for the photoreduction of Cr(VI) to Cr(III). Premised on the findings from experimental studies on Cr(VI) reductions, the factors that enhanced the process were identified, dilated, and interrogated. While the salient reaction conditions for the process optimization include the degree of ionization of reacting medium, available photogenerated electrons, reactor ambience, type of semiconductors, surface area of semiconductor, hole scavengers, quantum efficiency, and competing reactions, the relevant process variables are photocatalyst dosage, initial Cr(VI) concentration, interfering ion, and organic load. In addition, the practicability of photoreduction of Cr(VI) to Cr(III) was explored according to the potential for photocatalyst recovery, reactivation, and reuse reaction conditions and the process variables.

Role of Oil Palm Empty Fruit Bunch-Derived Cellulose in Improving the Sonocatalytic Activity of Silver-Doped Titanium Dioxide

In this study, a novel cellulose/Ag/TiO₂ nanocomposite was successfully synthesized via the hydrothermal method. The cellulose extracted from oil palm empty fruit bunch (OPEFB) could address the disposal issue created by OPEFB biomass. Characterization studies such as FESEM, EDX, HRTEM, XRD, FTIR, UV-Vis DRS, PL, XPS, and surface analysis were conducted. It was observed that the incorporation of cellulose could hinder the agglomeration, reduce the band gap energy to 3 eV, increase the specific surface area to 150.22 m³/g, and lower the recombination rate of the generated electron-hole pairs compared to Ag/TiO₂ nanoparticles. The excellent properties enhance the sonocatalytic degradation efficiency of 10 mg/L Congo red (up to 81.3% after 10 min ultrasonic irradiation) in the presence of 0.5 g/L cellulose/Ag/TiO₂ at 24 kHz and 280 W. The improvement of catalytic activity was due to the surface plasmon resonance effect of Ag and numerous hydroxyl groups on cellulose that capture the holes, which delay the recombination rate of the charge carriers in TiO₂. This study demonstrated an alternative approach in the development of an efficient sonocatalyst for the sonocatalytic degradation of Congo red.

Polysaccharide-based (nano)materials for Cr(VI) removal

Chromium is a potentially poisonous and carcinogenic species, which originates from human activities and various industries such as leather, steel, iron, and electroplating industries. Chromium is present in various oxidation states, among which hexavalent chromium (Cr(VI)) is highly toxic as a natural contaminant. Therefore, chromium, particularly Cr(VI), must be eliminated from the environment, soil, and water to overcome significant problems due to its accumulation in the environment. There are different approaches such as adsorption, ion exchange, photocatalytic reduction, etc. for removing Cr(VI) from the environment. By converting Cr(VI) to Cr(III), its toxicity is reduced. Cr(III) is essential for the human diet, even in small amounts. Today, biopolymers such as alginate, cellulose, gum, pectin, starch, chitin, and chitosan have received much attention for the removal of environmental pollutants. Biopolymers, particularly polysaccharides, are very useful compounds due to their OH and NH₂ functional groups and some advantages such as biodegradability, biocompatibility, and accessibility. Therefore, they can be widely applied in catalytic applications and as efficient adsorbents for the removal of toxic compounds from the environment. This review briefly investigates the application of polysaccharide-based (nano)materials for efficient Cr(VI) removal from the environment using adsorption/reduction, photocatalytic, and chemical reduction mechanisms.

Isolation and Production of Nanocrystalline Cellulose from Conocarpus Fiber

Conocarpus fiber is a lignocellulosic biomass rich in cellulose potentially used for producing nanocrystalline cellulose (NCC), a biomaterial extensively employed in various application fields. In the present work, different hydrolysis times of 10, 20 and 30 min were applied to chemically pre-treated Conocarpus fiber to produce CPNC1, CPNC2, and CPNC3 particles. With acid hydrolysis treatment, the yield of NCC product was successfully retained at 17–19%. Individual, rod-like shapes of NCC particles could be clearly observed under microscopy examination. From chemical composition analysis, a relatively pure cellulose compartment was produced for all NCC samples with substantial removal of lignin and hemicellulose. The physicochemical analysis proved that each nanoparticle sample possessed strong cellulose crystalline structure. For thermal analyses, the heat resistance of NCCs was gradually enhanced with the increased hydrolysis times. Therefore, the extracted NCC product from Conocarpus fiber could be a green nano-filler for developing nanocomposite material in the future.