CNC Surface Research Articles

Intaglio surface of CNC milled versus 3D printed maxillary complete denture bases – An in vitro investigation of the accuracy of seven systems

ObjectivesThe accuracy of the intaglio surface of maxillary complete dentures produced with a variety of digital manufacturing systems have been comprehensively investigated, however, not for multiple systems in the same study. This in vitro study endeavors to measure and compare the accuracy of the intaglio surface of maxillary complete denture bases constructed with different photopolymerization-based 3D printing and CNC milling systems. Materials and MethodsTwo subtractive manufacturing machines and five additive manufacturing machines were used to manufacture a maxillary denture bases (n = 10) for analysis. The samples were stored in artificial saliva at 37 °C for 7 days to mimic intraoral use before they were air dried for 5 min, and then scanned with an E3 dental laboratory scanner to generate STL files. A 3D metrology software program was used to analyze the data against the original CAD design. Statistical differences were determined with 1-way analysis of variance (ANOVA) and the Kruskal Wallis test (α=0.05). Color deviation heat maps were used to interpret areas of clinical significance. ResultsThe results indicated that the subtractive manufacturing method delivers the truest and most precise intaglio surface of maxillary complete denture bases. The additive manufacturing technique delivers less true and less precise results with inconsistency observed between the different systems as opposed to the subtractive manufacturing groups which showed no significant differences. ConclusionsWhen manufacturing a complete maxillary denture base subtractive manufacturing will deliver the most consistent and true results.

Low gelatin concentration assisted cellulose nanocrystals stabilized high internal phase emulsion: The key role of interaction

Low concentrations of gelatin (0.02–0.20 wt%) were applied to regulate the surface and interface properties of CNC (0.50 wt%) by forming CNC/G complexes. As gelatin concentration increased from 0 to 0.20 wt%, the potential value of CNC/G gradually changed from −44.50 to −17.93 mV. Additionally, various gelatin concentrations led to micromorphology changes of CNC/G complexes, with the formation of particle interconnection at gelatin concentration of 0.10 wt%, followed by network structure and enhanced aggregation at gelatin concentration of 0.15 and 0.20 wt% respectively. The water contact angle (25.91°-80.23°) and interface adsorption capacity of CNC/G were improved due to hydrophobic group exposure of gelatin. When gelatin concentration exceeded 0.10 % at a fixed oil phase volume fraction (75 %), a high internal phase emulsion (HIPE) stabilized by CNC/G can be formed with a good storage stability. The rheological and microstructure results of HIPE confirmed that low gelatin concentration can assist CNC to form stable emulsion structure. Especially, the auxiliary stabilization mechanism of various gelatin concentration was different. CNC/G-0.10 % and CNC/G-0.15 % stabilized HIPE mainly depended on the enhanced interface adsorption and network structure, while CNC/G-0.20 % stabilized HIPE mainly relied on enhanced interface adsorption/accumulation due to weak electrostatic repulsion and aggregate granular morphology of CNC/G-0.20 %.

Multi-axis CNC finishing and surface roughness prediction of TC11 titanium alloy open integral micro impeller

The titanium alloy open integral micro impeller has a strong material strength and high removal rate in the field of multi-axis CNC machining. The flow channel is tiny and the blades are thin and highly twisted. It is difficult to control the surface accuracy and prone to overcutting and undercutting. The NX2212 software post-processing module plans two distinct blade finishing process routes and verifies them using virtual machine tool simulation, taking into account the technical challenges of micro impeller machining. Following verification, the tool path machining code is imported into MATLAB for data fitting. The workpiece surface working condition is determined based on the simulation findings, the blade surface roughness value is calculated, and a physical simulation model of blade finishing is created in the finite element analysis software. The outcomes demonstrate how well the “segmented and sub-regional cutting” processing method may raise blade accuracy. The leading and trailing edges of the blade both had surface roughness increases of 4.86% and 4.19%. The surface morphology of the micro impeller is measured using a white light interferometer, and it is CNC machined using two distinct process methods. The findings demonstrate that there is a significant difference between the value calculated by the finite element analysis software and the surface roughness value measured experimentally which together make up less than 5%. An investigation of the impact of cutting parameters on the surface roughness of micro-structure components is carried out using a three factor, three-level BBD experiment that is founded on the second-order response surface method. The findings indicate that the feed per tooth influences surface roughness more significantly than cutting depth and cutting speed for a reasonable range of cutting parameters; Surface roughness will rise with lower or higher cutting speeds; Raising the feed per tooth and the cutting speed simultaneously may reduce surface roughness; Surface roughness can be accurately predicted and controlled using the second-order response surface method.

A strategy for effective improvement the dispersion of cellulose nanocrystals and adhesive properties of starch-matrix sizing agent on polyester roving via dopamine self-polymerization

Starch sizing agent has poor mechanical property, strong hygroscopicity and weak adhesion to polyester yarns. In this study, cellulose nanocrystals embellished by dopamine (CNC-DA) as the filler of starch is used for sizing polyester roving. The structure of CNC-DA is characterized, and the structure and properties of starch-matrix nanocomposite (CS/CNC-DA) are studied. The results show that DA self-polymerizes on the surface of CNC to form polydopamine. With the increase of CNC-DA amount, tensile strength, elongation at break, fracture work, the initial degradation temperature, water contact angle of CS/CNC-DA film, and adhesion of CS/CNC-DA to polyester roving increase first, and then decrease, while moisture uptake of CS/CNC-DA film shows the opposite trend. When the addition amount of CNC-DA is 5 wt%, the corresponding tensile strength, elongation at break and fracture work reach maximum that are 53.82 MPa, 4.87% and 1.69 MJ/m3, respectively. Breaking force, elongation at break and work-to-break of sizing polyester roving by CS/5CNC-DA are 143.47 N, 15.49% and 550.95 N·mm, respectively. These are attributed to the better dispersion of CNC-DA in starch-matrix nanocomposite film and the stronger interfacial interaction between CNC-DA and starch.

Mobile-Based augmented reality (AR) module for guided operations of CNC surface roughness machine

Immersive technologies are gaining considerable traction in manufacturing industries to address issues linked with the shortage of skilled workforce. Augmented Reality (AR) is one of the technologies with great potential to address this problem due to simplified hardware requirements and adaptability to various domains. The present work utilizes AR technology in the context of machine operation guidance to solve the problem of skilled human resources for operating delicate manufacturing machines. A mobile-based AR application has been developed using the Vuforia engine and Unity 3D platform for a CNC surface roughness machine. The AR module is designed to assist and guide novice operators in efficiently executing various machine setting, operation, and software utilization tasks. The subjective and objective evaluation of the developed system has been carried out to capture user feedback and review. It has been demonstrated that the developed mobile-based AR module offers extensive utility, ease of operation, and practical utility.© 2023 Society of Manufacturing Engineers (SME). Published by Elsevier Ltd. All rights reserved.This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/)Peer-review under responsibility of the Scientific Committee of the NAMRI/SME.

One-pot strategy to fabricate conductive cellulose nanocrystal-polyethylenedioxythiophene nanocomposite: Synthesis mechanism, modulated morphologies and sensor assembly

Simple preparation, good conductivity, and excellent hydrophilicity are in urgent demand due to fast growth of wearable intelligent devices. Cellulose nanocrystal-polyethylenedioxythiophene (CNC-PEDOT) nanocomposites with modulated morphology were prepared through Iron (III) p-toluenesulfonate hydrolysis of commercialized microcrystalline cellulose (MCC) and in situ polymerization of 3,4-ethylenedioxythiophene monomers (EDOT) through one-pot green synthesis, where preparation and modification of CNC were obtained for uses as templates to anchor PEDOT nanoparticles. The resultant CNC-PEDOT nanocomposite gave well-dispersed PEDOT nanoparticles with sheet-like structure on the CNC surface, possessing higher conductivity and improved hydrophilicity or dispersibility. Subsequently, a wearable non-woven fabrics (NWF) sensor was successfully assembled by dipping the conductive CNC-PEDOT, and showed excellent sensing response for multiple signals (subtle deformation from various human activities and temperature). This study provides a feasible and large-scale production of CNC-PEDOT nanocomposites and their applications in wearable flexible sensors and electronic devices.

Effect of Machining on Mechanical Properties of Borosilicate Glasses

Abstract Although optical properties are essential for materials for optical purposes, their mechanical properties must also be considered as they directly govern their practical applicability as well as their machining. The machining of optical glasses is mainly carried out by mechanical removal of the material using free or bonded abrasives. The relationship between the local mechanical properties of three types of borosilicate glasses used to produce optical elements (mirrors) and the type of surface machining was investigated. The samples were machined using two approaches, namely 7-axis CNC surface machining and conventional manual machining. Advanced analysis of nano/micro-mechanical properties was performed on glass samples using quasi-static nanoindentation and microindentation and dynamic impact test complemented by the analysis of the acoustic emission signals generated during the mechanical tests. The results show a difference in mechanical properties between industrial and optical borosilicate glasses. The type of machining has a strong influence on studied mechanical properties and surface quality. Glasses manufactured by CNC have more pronounced acoustic emission signal and crack more than glasses manufactured by hand. The different behavior of hand- and CNC-machined surfaces can be linked to different subsurface damage caused by different contact conditions between the workpiece and the instrument/abrasive. As a result, a different density of surface and especially (near)-subsurface flaws are present in the glass. Simax is slightly softer than BG33 glass, which together with the less pronounced AE may indicate a lower amount of subsurface cracks/damage.

Highly sensitive, flexible and transparent TiO2/nanocellulose humidity sensor for respiration and skin monitoring

Because of its biodegradability, biocompatibility, strong hydrophilicity, and high specific surface area, nanocellulose has been considered as a potential material for flexible humidity sensors. Herein, we developed a TiO2/CNC humidity sensor with good flexibility based on the nanocellulose (CNC) prepared by the enzymatic method. Nano TiO2 with a positive charge was adsorbed on the surface of CNC with a negative charge, and conductive fibers were obtained by an electrostatic self-assembly process. The TiO2/CNC composite exhibits high optical transmittance (84.5% at 600 nm), flexibility (the tensile elongation reaches 57.82%), and robust mechanical property (the tensile strength reaches 44.66 MPa). The obtained TiO2/CNC humidity sensor achieved high humidity response (R0/R = 450.9), rapid response/recovery speed (22/13 s), folding durability (20 times), and long-term stability (40 days). TiO2/CNC had outstanding performance in actual respiratory rate detection, and the assembled TiO2/CNC skin moisture detector with flexibility and transparency could monitor human body moisture in real-time, showing its potential as a smart wearable device.

Non‐Covalent Polymer Surface Modification of Cellulose Nanocrystals Using Block Copolymers

AbstractCellulose nanocrystals (CNC) possess desirable mechanical and optical properties that make them a candidate in the development of the next generation of polymer‐based composites. However, CNC also have a critical issue associated with their use: their hydrophilicity and incompatibility with hydrophobic polymers. CNC surface properties must be modified for them to be successfully implemented by the industrial sector. Grafting (co)polymers chains on the CNC surface can provide compatibility to CNC with hydrophobic matrices and expand their potential range of applications. In this communication preliminary results of a simple method to functionalize CNC surface are reported using block copolymers, where a cationic block anchors via complexation to the anionically charged CNC surface and the other block acts as a stabilizing block, providing dispersibility in various solvents. This is a much simpler and less expensive method than current routes based on covalent modification. The block copolymers poly(polyethylene glycol methacrylate)‐b‐poly(N‐butyl‐N′‐vinyl imidazolium bromide) (PPEGMA‐b‐PBuVIm) and poly(styrene)‐b‐PBuVIm (PS‐b‐PBuVIm) are first synthesized via nitroxide‐mediated polymerization and then non‐covalently adsorbed on the CNC surface. The functionalization has been confirmed via FT‐IR and TGA. The dispersion of polymer‐modified CNC materials in organic solvents is evaluated via dynamic light scattering. Modified CNC yielded stable dispersions in organic solvents.

Optimization of drilling process parameters for self-lubricants reinforced aluminium metal matrix composites

Aluminium matrix composites (AMCs) find a wide spectrum of application in various fields of engineering and technology. Owing to the below par inherent characteristics of unreinforced AMCs, reinforcements are used to improve the characteristics of AMCs. Reinforcing the self-lubricating graphite (Gr) and molybdenum disulphide (MoS2) in aluminium matrix was found to improve the machinability and surface finish of the composites which in turn enhances the application prospects. In the current investigation, aluminium alloy 2219 (AA2219) was reinforced with Gr and MoS2 and the composites were fabricated by conventional casting technique. Drilling behavior of the composites were investigated by conducting drilling experiments in CNC machining center and surface roughness of the holes were measured. Experiments were designed by full factorial method. Results of the experiments portrayed that the composites with Gr as reinforcement exhibited better drilling behavior when compared with MoS2 reinforced AA2219 composites.

Investigations on the interactions of proteins with nanocellulose produced via sulphuric acid hydrolysis

The investigation of protein–nanoparticle interactions contributes to the understanding of nanoparticle bio-reactivity and creates a database of nanoparticles for use in nanomedicine, nanodiagnosis, and nanotherapy. In this study, hen's egg white was used as the protein source to study the interaction of proteins with sulphuric acid hydrolysed nanocellulose (CNC). Several techniques such as FTIR, zeta potential measurement, UV–vis spectroscopy, compressive strength, TGA, contact angle and FESEM provide valuable information in the protein–CNC interaction study. The presence of a broader peak in the 1600–1050 cm−1 range of CNC/egg white protein FTIR spectrum compared to the 1600–1050 cm−1 range of CNC sample indicated the binding of egg white protein to CNC surface. The contact angle with the glass surface decreased with the addition of CNC to egg white protein. The FESEM EDX spectra showed a higher amount of N and Na on the surface of CNC. It indicates the density of protein molecules higher around CNC. The zeta potential of CNC changed from −26.7 ± 0.46 to −21.7 ± 0.2 with the introduction of egg white protein due to the hydrogen bonding, polar bonds and electrostatic interaction between surface CNC and protein. The compressive strength of the egg white protein films increased from 0.064 ± 0.01 to 0.36 ± 0.02 MPa with increasing the CNC concentration from 0 to 4.73% (w/v). The thermal decomposition temperature of CNC/egg white protein decreased compared to egg white protein thermal decomposition temperature. According to UV–Vis spectroscopy, the far-UV light (207–222nm) absorption peak slightly changed in the CNC/egg white protein spectrum compared to the egg white protein spectrum. Based on the results, the observations of protein nanoparticle interactions provide an additional understanding, besides the theoretical simulations from previous studies. Also, the results indicate to aim CNC for the application of nanomedicine and nanotherapy. A new insight given by us in this research assumes a reasonable solution to these crucial applications.

Grafting polymers from cellulose nanocrystals via surface‐initiated atom transfer radical polymerization

AbstractCellulose nanocrystals (CNC) are rod‐like nanoparticles extracted from cellulose. Due to their fascinating properties—renewable, biocompatible, non‐toxic, biodegradable, excellent mechanical performances, high specific surface area, water dispersible, can be assemble in chiral nematic phases—CNC have shown promise in various fields, including oil recovery, polymer composites reinforcing, hydrogels, aerogels, supercapacitors, energy saving buildings, cosmetics, papermaking, coatings, liquid crystals, and waste water treatment. However, the hydrophilic surface of CNC hinders their broader applications. In this context, surface modification of CNC via polymer grafting can be used to finely tune their surficial properties and endow CNC with a variety of functionalities, such as conductivity, pH or temperature responsiveness, reactivity…In particular, surface‐initiated atom transfer radical polymerization (SI‐ATRP) is a powerful tool to graft various polymers with a high grafting density and controlled chain length. In this review, the precise control of grafted polymers from CNC via SI‐ATRP is first discussed, including issues related to the polymer grafting density, chain length and possibility to perform an asymmetric grafting. Then, the properties and applications of CNC grafted with a variety of polymers are presented. Finally, some challenges and outlook related to the SI‐ATRP method applied to the field of CNC is discussed.

Coronae of an active fast rotator FR Cnc

We present the first detailed X-ray study and simultaneous optical observations of the active fast rotating star FR Cnc. The X-ray spectra are found to be explained by two-temperature plasma model with temperature of cool and hot components of 0.34 and 1.1 keV, respectively. The X-ray light curve in the 0.5–2.0 keV energy band is found to be rotationally modulated with the degree of rotational modulation of \(\sim\)17%. We have also found that the X-ray light curve is anti-correlated with the optical light and colour curves in the sense that maximum X-ray light corresponds to minimum optical light and cooler region on the surface of FR Cnc. The X-ray luminosity of FR Cnc is found to be almost consistent in the last 30 years with an average value of \(4.85\times 10^{29}\) erg \(\hbox {s}^{-1}\) in the 0.5–2.0 keV energy band.

Real single grain grinding FEM simulation for case-hardened steel based on equivalent contact area analysis

Abstract Grinding is an indispensable phase in the gear production chain as it allows very stringent requirements characteristic of the automotive sector to be satisfied. The main goal of this finishing process is to ensure compliance with the surface integrity and dimensional tolerance specifications of the product. A single-grain grinding FEM model has been implemented to predict grinding load values based on real grain geometry using a set of Johnson & Cook coefficients able to represent the flow stress curve of a typical gear case-hardened steel 27MnCr5. Grain geometry acquired through computed tomography was imported into three-dimensional process simulation software DEFORM-3D. As the use of real grain geometry leads to time-consuming simulations, an equivalent defined geometry grain was implemented to compare cutting behavior and calculate maximum force values through real contact area analysis under the same process parameters. Calculated loads were subsequently compared with experimental results, showing good agreement with a maximum percentage difference less than 13% for two different grain geometries. Grinding force measurements were performed in a single-grain configuration on a CNC surface grinding machine adopting a wheel speed of 384 rad/s, feed rate of 8.6 mm/s and a depth of cut of 0.1 mm.

Green one-step synthesis of cellulose nanocrystal/ ZnO nanohybrid with high photocatalytic activity

In this work, nanohybrid of zinc oxide/ cellulose nanocrystals (ZnO/CNC) was successfully prepared by using a low cost and green method for photocatalytic degradation of methylene blue (MB). CNC had been derived through the hydrolysis reaction by citric/hydrochloric acid from the pure cellulose isolated from Vietnamese Nypa fruticans trunk. The obtained CNC with carboxyl groups could act as a stabilizing and supporting agent to anchor ZnO nanoparticles. The chemical and crystal structures, morphology, thermal and photocatalytic properties of the ZnO/CNC nanohybrid were characterized by FESEM, FTIR, XRD, FESEM, BET, EDX, TGA, DRS and photocatalytic tests. Analyses of FTIR spectra, XRD, and FESEM indicated that the ZnO nanocrystals with the size of 50 nm formed and loaded on the surface of CNC. The TGA analysis demonstrated that the ZnO loading sample (ZnO/CNC) had the thermal degradation onset temperature higher than that of neat CNC. ZnO/CNC cuold be absorpted ultraviolet light and have high value of specific surface area (SBET), based on the DRS spectra and the nitrogen adsorption – desorption isotherms analysis, respectively. ZnO/CNC displayed more photocatalytic activity than pure ZnO upon degradation of methylene blue due to strong interaction between the CNC and ZnO nanoparticles. The maximum degradation of MB was about 95% in 150 minutes for the ZnO/CNC.

Cellulose nanocrystals from bleached rice straw pulp: acidic deep eutectic solvent versus sulphuric acid hydrolyses

The present work aims to investigate the feasibility of oxalic acid-choline chloride deep eutectic solvent (OA-ChCl DES), which serves as a promising green solvent that utilized in the acidic deep eutectic solvent (DES) hydrolysis. Oxalic acid-choline chloride DES cellulose nanocrystal (OA-ChCl DES CNC) was isolated from the bleached DES treated pulp (BP) through the acidic DES hydrolysis using 1:1 molar ratio of OA-ChCl DES. The functional groups, crystallinity index, morphological structure, particle size, zeta potential, thermal stability and surface chemistry of the OA-ChCl DES CNC were compared with the sulphuric acid cellulose nanocrystal (SA-CNC) that prepared via sulphuric acid hydrolysis. The findings revealed the presence of negatively charged carboxyl groups on OA-ChCl DES CNC surface after the acidic DES hydrolysis. The physicochemical analyses verified that the OA-ChCl DES CNC was in nano-sized range with polydispersity index (PdI) of 0.56, indicating slightly monodispersed nanoparticles. A stable OA-ChCl DES CNC colloidal suspension with zeta potential value of −52.1 ± 5.2 mV was obtained. The OA-ChCl DES CNC outweighed the SA-CNC in term of thermal stability (288 °C) despite having a slightly lower crystallinity index (76.7%). In fact, the OA-ChCl DES CNC with a yield of 55.1% was achieved through the acidic DES hydrolysis, suggesting that the OA-ChCl DES was capable of promoting efficient cleavage of strong hydrogen bonds in BP.

Hydrothermal preparation of Ag/Fe3O4/Cellulose nanocrystals nanocomposite and its application in methylene blue removal

The preparation of reusable and eco-friendly materials from renewable biomass resources such as cellulose is an inevitable choice for the sustainable development. In this paper, Ag/Fe3O4/cellulose nanocrystals (CNC) nanocomposite was prepared and investigated its application in methylene blue (MB) removal. In the procedure, CNC was isolated from Vietnamese coconut husk fibers (CCH) biomass via a formic/peroxyformic acid process treatment and hydrochloric acid hydrolysis. The obtained CNC was used as a starting material to prepare Ag/Fe3O4 nanostructure by facile and green hydrothermal method. The nanocomposite was characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), thermogravimetric analysis (TGA), and magnetic properties via vibrating sample magnetometer (VSM) analysis. The results showed that Ag/Fe3O4 was formed with a particle structure and dispersed on the CNC surface. All samples exhibited magnetic properties and the saturation magnetization (Ms) of Ag/Fe3O4 composite was reduced from 48 to 12 emu/g with adding CNC. Ag/Fe3O4/CNC magnetic nanocomposite demonstrated good adsorption of MB solution and exhibited a fast catalytic reduction of MB after immersion treatment by NaBH4, which showed potential applications in water treatment.

Properties of polyacrylamide composites reinforced by cellulose nanocrystals

In this work, a series of polyacrylamide/cellulose nanocrystal (PAM/CNC) composites with a wide range of compositions were prepared by a solution casting method. Subsequently, the influence of the PAM conformation on the behaviour of the PAM/CNC composites was studied. The microstructural, thermal, and mechanical properties of the PAM/CNC composites were also investigated, as well as their flocculation and dispersion behaviour. Thermal degradation of both CNC and PAM in the composites occurred simultaneously, at a much higher temperature than the degradation of the neat CNC. By TEM and SEM, PAM globule aggregates in the PAM/CNC composites were detected. With an increase in the medium acidity, the PAM globule aggregate size of in the composites decreased. Moreover, the composite films cast from high pH solutions (extended PAM conformation) exhibited superior strength properties than those cast from low pH solutions (contracted coil PAM conformation). The PAM globule conformation provided good re-dispersibility of the freeze-dried PAM/CNC composites by preventing aggregation of the CNC particles. The PAM globule adsorption onto the CNC particles caused CNC surface hydrophobization and a decrease in their surface charge, while maintaining high colloidal stability of the CNC suspensions. Furthermore, the CNC particles with adsorbed PAM were demonstrated to be useful as emulsifiers and compatibilisers.

Investigating Methylene Blue Adsorption and Photocatalytic Activity of ZnO/CNC Nanohybrids

Nanohybrids of zinc oxide/cellulose nanocrystals (ZnO/CNCs) were successfully prepared by using a low cost and green method for adsorption and photocatalytic degradation of methylene blue (MB). CNCs have been derived through the hydrolysis reaction by citric/hydrochloric acid from the pure cellulose isolated from Vietnamese Nypa fruticans trunk. The influence of the Zn2+ ion concentration on the morphology, microstructure, and thermal properties as well as the photocatalytic activity of the ZnO/CNC nanohybrids was investigated in detail. Analyses of FTIR spectra, XRD, and SEM indicated that the ZnO nanocrystals with the size of 50 nm formed and loaded on the surface of CNC. Based on the DRS spectra and the nitrogen adsorption–desorption isotherms (BET) analysis, the absorption of ultraviolet light with a strong absorption band around 400 nm was found for all the ZnO/CNC nanohybrids, and the values of specific surface areas (SBET) of materials can be controlled by changing the concentration ratio of Zn2+ ion and CNC. The TGA analysis demonstrated that the ZnO loading samples (ZnO/CNC) had the thermal degradation onset temperature higher than that of neat CNC. The effect of MB removal showed the results which were contributed not only by the adsorption ability of CNC but also by the photocatalytic activity of ZnO. The photocatalytic efficiency significantly depended on the content of ZnO loading. The maximum degradation of MB was about 95% in 150 min for the ZnO/CNC-1.0 sample in which the concentration ratio of zinc-precursor Zn(NO3)2·6H2O and CNC was 1.0.

Novel design of Fe-Cu alloy coated cellulose nanocrystals with strong antibacterial ability and efficient Pb2+ removal

We report a facile method to prepare a novel composite based on Fe-Cu alloy decorated cellulose nanocrystals (Fe-Cu@CNC) via simple oxidation-reduction reaction. Spherical zero-valent iron nanoparticles (NZVI) and sheet-like copper nanoparticles were serially anchored on the CNC surface, and the generated composite exhibited excellent antibacterial activities and highly efficient Pb2+ removal. The composites had high antibacterial ratios of 95.9 %–99.9 %, because superoxide radicals can cause irreversible damage to the bacteria, eventually leading to apoptosis and bacterial death. Meanwhile, the Fe-Cu@CNC composite showed quick Pb2+ ion removal, reaching a 70.76 % removal within 5 min, a total removal of 93.98 % after 1 h, and excellent reusability (retaining removal efficiency of 80.41 % after six cycles). The adsorption kinetics demonstrated that the adsorption behavior can be described by pseudo-second-order kinetic model (R2>0.99). This study offers a new strategy to prepare a promising composite with advanced antibacterial and heavy metal removal properties for wastewater treatment.