The impact of surface functionalization of cellulose following simulated digestion and gastrointestinal cell-based model exposure.

Surface-functionalized cellulose materials are developed for various purposes, including food additives and food contact materials. A new biologically relevant testing strategy has been developed based on guidance from the European Food Safety Authority to demonstrate the safety of several next-generation surface-functionalized cellulose materials. This strategy involves a complex three-stage simulated digestion to compare the health effects of thirteen novel different types of cellulose. The physical and chemical properties of surface-functionalized fibrillated celluloses differed depending on the type, amount, and location of functional groups such as sulfonate, TEMPO-oxidized carboxy, and periodate-chlorite oxidized dicarboxylic acid celluloses. Despite exposure to gastrointestinal fluids, the celluloses maintained their physicochemical properties, such as negative surface charges and high length-to-width/thickness aspect ratios. An established intestinal co-culture model was used to measure cytotoxicity, barrier integrity, oxidative stress, and pro-inflammatory response to create a toxicological profile for these unique materials. We conclude that the C6 carboxylated cellulose nanofibrils by TEMPO-oxidation induced the most toxicity in the biological model used in this study and that the observed effects were most prominent at the 4-hour post-exposure time point.

A trace fiber population study on upholstered chairs in a military environment.

This fiber population study has assessed the prevalence of the color and type of trace fibers present on upholstered seats in a specific setting to identify the most common and rare colors and to determine their evidentiary value. Nearly 22,000 fibers were collected via tape lifts from 25 fabric covered chair seats in a lobby area on Beale Air Force Base and examined microscopically to determine their apparent colors. Overall, blue and white/colorless were the most and nearly equally common colors (32.0 % and 31.5 %, respectively), followed by black/grey (19.6 %), brown (8.6 %), yellow/tan (4.9 %), and red/pink (2.5 %), while orange, purple, and green were the rarest (0.5 %, 0.3 %, and 0.3 %, respectively). Among rarest color fibers, plant-based fibers were predominant (77.7 %), consisting of mainly cotton, followed by synthetic fibers (17.4 %), then the least prevalent animal fibers (5.0 %). These color rankings align similarly to previous studies, despite the prominence of blue color fibers and higher proportions of brown and yellow/tan color fibers.

Aqueous exfoliation and dispersion of monolayer and bilayer graphene from graphite using sulfated cellulose nanofibrils.

Amphiphilic sulfated cellulose nanofibrils were synthesized with yields in excess of 99% by sulfation of dissolving pulp cellulose using chlorosulfonic acid in anhydrous N,N-dimethyl formamide followed by high-speed blending. The sulfation level was stoichiometrically tunable to between 1.48 and 2.23 mmol g-1. The optimized SCNF demonstrated the ability to act as an effective dispersant for graphene produced via exfoliation in aqueous media, allowing for the production of aqueous stabilized graphene with 3.9 ± 0.3 wt% graphite to graphene conversion and suspended solids comprised of 19.5 ± 1.5 wt% graphene. Graphene exfoliated with SCNF was observed to consist exclusively of mono- and bilayers, with 42% of sheets being monolayer. Furthermore, it was demonstrated that SCNF defibrillation and graphene exfoliation could be combined into a single one-pot process.

Regioselectively Carboxylated Cellulose Nanofibril Models from Dissolving Pulp: C6 via TEMPO Oxidation and C2,C3 via Periodate-Chlorite Oxidation.

Regioselective C6 and C2,C3 carboxylated cellulose nanofibrils (CNFs) have been robustly generated from dissolving pulp, a readily available source of unmodified cellulose, via stoichiometrically optimized 2,2,6,6-tetramethylpyperidine-1-oxyl (TEMPO)-mediated and sequential sodium periodate-sodium chlorite (PC) oxidation coupled with high-speed blending. Both regioselectively optimized carboxylated CNF series possess the widest ranges of comparable charges (0.72-1.48 mmol/g for T-CNFs vs. 0.72-1.10 mmol/g for PC-CNFs), but similar ranges of thickness (1.3-2.4 nm for T-CNF, 1.8-2.7 nm PC-CNF), widths (4.6-6.6 nm T-CNF, 5.5-5.9 nm PC-CNF), and lengths (254-481 nm T-CNF, 247-442 nm PC-CNF). TEMPO-mediated oxidation is milder and one-pot, thus more time and process efficient, whereas the sequential periodate-chlorite oxidation produces C2,C3 dialdehyde intermediates that are amenable to further chemical functionalization or post-reactions. These two well-characterized regioselectively carboxylated CNF series represent coherent cellulose nanomaterial models from a single woody source and have served as references for their safety study toward the development of a safer-by-design substance evaluation tool.

Tunable poly(lauryl methacrylate) surface grafting via SI-ATRP on a one-pot synthesized cellulose nanofibril macroinitiator core as a shear-thinning rheology modifier and drag reducer.

The optimally one-pot synthesized 2-bromoproponyl esterified cellulose nanofibril (Br-CNF) has been validated as a robust macroinitiator for self-surface-initiated atom transfer radical polymerization (SI-ATRP) of lauryl methacrylate (LMA) in tunable graft lengths and high conversions of up to 92.7%. SI-ATRP of LMA surface brushes on Br-CNF followed first order kinetics in lengths at up to 46 degree of polymerization (DP) based on mass balance or 31 DP by solution-state 1H NMR in DMSO-d6. With increasing PLMA graft lengths, Br-CNF-g-PLMA cast films exhibited increasing hydrophobicity with water contact angles from 80.9° to 110.6°. The novel Br-CNF-g-PLMA exhibited dual shear thinning behavior of the Br-CNF core as evident by n < 1 flow behavior index and drag reducing properties of PLMA grafts with increased viscosity at up to 21 071×. Br-CNF-g-PLMA with 46 DP could be fully dispersed in silicon pump oil to function as a drag reducer to enhance viscosity up to 5× at 25, 40, and 55 °C. The novel macroinitiator capability of Br-CNF in SI-ATRP of vinyl monomers and the bottlebrush-like LMA surface grafted Br-CNF as highly effective viscosity modifier and drag reducer further demonstrate the versatile functionality of Br-CNF beyond hydrophobic coatings and reactive polyols previously reported.

Protonation of Surface Carboxyls on Rice Straw Cellulose Nanofibrils: Effect on the Aerogel Structure, Modulus, Strength, and Wet Resiliency.

Rice straw cellulose nanofibrils from the optimal 2,2,6,6-tetramethylpiperidine-1-oxyl oxidation/blending process carrying 1.17 mmol/g surface carboxyls were protonated to varying charged (COO-Na+) and uncharged (COOH) surfaces. Reducing the electrostatic repulsion of surface charges by protonation with hydrochloric acid from 11 to 45 and 100% surface carboxylic acid most prominently reduced the aerogel densities from 8.0 to 6.6 and 5.2 mg/cm3 while increasing the mostly open cell pore volumes from 125 to 152 and 196 mL/g. Irrespective of charge levels, all aerogels were amphiphilic, super-absorptive, stable at pH 2 for up to 30 days, and resilient for up to 10 repetitive squeezing-absorption cycles. While these aerogels exhibited density-dependent dry [11.3 to 1.5 kPa/(mg/cm3)] and reduced wet [3.3 to 1.4 kPa/(mg/cm3)] moduli, the absorption of organic liquids stiffened the saturated aerogels. These data support protonation as a critical yet simple approach toward precise control of aerogels' dry and wet properties.

Stretchable One-Dimensional Conductors for Wearable Applications.

Continuous, one-dimensional (1D) stretchable conductors have attracted significant attention for the development of wearables and soft-matter electronics. Through the use of advanced spinning, printing, and textile technologies, 1D stretchable conductors in the forms of fibers, wires, and yarns can be designed and engineered to meet the demanding requirements for different wearable applications. Several crucial parameters, such as microarchitecture, conductivity, stretchability, and scalability, play essential roles in designing and developing wearable devices and intelligent textiles. Methodologies and fabrication processes have successfully realized 1D conductors that are highly conductive, strong, lightweight, stretchable, and conformable and can be readily integrated with common fabrics and soft matter. This review summarizes the latest advances in continuous, 1D stretchable conductors and emphasizes recent developments in materials, methodologies, fabrication processes, and strategies geared toward applications in electrical interconnects, mechanical sensors, actuators, and heaters. This review classifies 1D conductors into three categories on the basis of their electrical responses: (1) rigid 1D conductors, (2) piezoresistive 1D conductors, and (3) resistance-stable 1D conductors. This review also evaluates the present challenges in these areas and presents perspectives for improving the performance of stretchable 1D conductors for wearable textile and flexible electronic applications.

2-Bromopropionyl Esterified Cellulose Nanofibrils as Chain Extenders or Polyols in Stoichiometrically Optimized Syntheses of High-Strength Polyurethanes.

2-Bromopropionyl bromide esterified cellulose nanofibrils (Br-CNFs) facilely synthesized from one-pot esterification of cellulose and in situ ultrasonication exhibited excellent N,N-dimethylformamide (DMF) dispersibility and reactivity to partially replace either chain extender or soft segment diol in the stoichiometrically optimized syntheses of polyurethanes (PUs). PUs polymerized with Br-CNF to replace either 11 mol% 1,4-butadiol chain extender OHs or 1.8 mol% polytetramethylene ether glycol OHs, i.e., 1.5 or 0.3 wt% Br-CNF in PUs, exhibited an over 3 times increased modulus, nearly 4 times higher strength, and a 50% increase in strain. In either role, the experimental modulus exceeding those predicted by the Halpin-Tsai model gave evidence of the stoichiometrically optimized covalent bonding with Br-CNF, while the improved strain was attributed to increased hydrogen-bonding interactions between Br-CNF and the soft segment. These new Br-CNFs not only offer novel synthetic strategies to incorporate nanocelluloses in polyurethanes but also maximize their reinforcing effects via their versatile polyol reactant and cross-linking roles, demonstrating promising applications in the synthesis of other polymers.

One-pot synthesis of 2-bromopropionyl esterified cellulose nanofibrils as hydrophobic coating and film.

Hydrophobic 2-bromopropionyl esterified cellulose nanofibrils (Br-CNFs) have been facilely produced via one-pot esterification of cellulose with 2-bromopropionyl bromide (BPB) then in situ disintegrated by ultrasonication in the same reaction media. Br-CNFs optimally produced by this robust esterification-ultrasonication approach, i.e., 5 : 1 BPB to anhydroglucose (AGU) molar ratio, 23 °C, 6 h and ultrasonication (50% amplitude, 30 min), were 4.6 nm thick, 29.3 nm wide, and 1 µm long in 71% yield and 48% crystallinity. Successful 2-bromopropionyl esterification of cellulose was confirmed by FTIR and 1H NMR. The degree of substitution (DS) of surface hydroxyl to 2-bromopropanoate was determined to be between 0.53 (DSs) based on XRD and Br-CNF dimensions and 0.56 (DSNMR) from solution-state 1H NMR. Br-CNF dispersions in DMF exhibited Newtonian behaviors at concentrations below and shear thinning behaviors above 0.5%, enabling homogeneous deposition at dilute concentrations up to 0.01% into a few nm ultra-thin layers as well as blade coating of gel into ca. 100 µm thick film, all similarly hydrophobic with surface water contact angles (WCAs) in the range of 70-75°. The ultra-high modulus and strength film from gel coating further showed the potential for dual high-strength and hydrophobic applications of Br-CNFs.

Sulfated Cellulose Nanofibrils from Chlorosulfonic Acid Treatment and Their Wet Spinning into High-Strength Fibers.

This paper presents the proof of concept for a facile sulfation-disintegration approach toward generating sulfated cellulose nanofibrils (SCNF) via direct sulfation of rice straw cellulose with chlorosulfonic acid (HSO3Cl) followed by blending. The direct sulfation of cellulose with chlorosulfonic acid (HSO3Cl) was optimized at acid ratios of 1-1.5 HSO3Cl per anhydroglucose unit (AGU) and short reaction times (30-60 min) at ambient temperature to produce SCNF with tunable charges of 1.0-2.2 mmol/g, all in impressively high yields of 94-97%. SCNF were characterized via AFM, TEM, FTIR, and XRD. SCNF lengths (L: 0.75-1.24 µm) and widths (W: 3.9-5.9 nm) decreased with harsher sulfation, while heights (H: 1.23-1.32 nm) remained relatively static. The SCNF had uniquely anisotropic cross sections (W/H: 3.0-4.7) and high aspect ratios (L/H: 568-984) while also exhibiting amphiphilicity, thixotropy, and shear thinning behaviors that closely followed a power law model. Aqueous SCNF dispersions could be wet spun into organic and mixed organic/ionic coagulants, producing continuous fibers possessing an impressively high tensile strength and Young's modulus of up to 675 ± 120 MPa and 26 ± 5 GPa, respectively.

First report of electrospun cellulose acetate nanofibers mats with chitin and chitosan nanowhiskers: Fabrication, characterization, and antibacterial activity.

Physical adsorption has shown to be facile and highly effective to deposit chitosan nanowhiskers (CsNWs, 60 % deacetylated, length: 247 nm, thickness: 4-12 nm, width:15 nm) on electrospun cellulose acetate nanofibers (CANFs, 560 nm) to effect complete surface charge reversal from negatively charged CANFs (-40 mV) to positively charged CsNWs-adsorbed CANFs (+8 mV). The CsNWs coverage did not alter the smooth and homogeneous morphology of fibers, as observed from SEM images. Biological assays showed the CsNWs covered nanofibers were effective against the Gram-negative bacterium E. coli, reducing 99 % of colony forming units (CFU) in 24 h and atoxic to healthy Vero cells. The use of CsNWs to modify cellulose fiber surfaces has been proved to be efficient and may be applied to a broad scope of fields, especially as biomaterials and biomedical applications.

Amphoteric Soy Protein-Rich Fibers for Rapid and Selective Adsorption and Desorption of Ionic Dyes.

Uniquely amphoteric soy protein (SP)-rich ultra-fine fibers (231 nm average diameter) have been facilely electrospun from aq. colloids and rendered water-insoluble by heating (150 °C, 12 h) to be highly stable over 14 d (pH 7) as well as under extremely acidic to basic (pH 0-10, 2 d) or at boil (2 h) conditions. The SP-rich fibrous membranes are easily tuned to be charged either negatively by deprotonation above or positively by protonation below the 4.5 PI of SPs. This pH-responsive amphoterism has been demonstrated for rapid adsorption of either cationic or anionic dyes, selective adsorption of either dye from their mixtures, and repetitive adsorption/desorption to recover and reuse both dyes and membranes. Chemisorption and heterogeneous adsorption of ionic dyes was confirmed by close fitting to the pseudo-second-order kinetic model (R 2 = 0.9977-0.9999) and Freundlich adsorption isotherm (R 2 = 0.9879). This is the first report of water-resilient and pH-robust ultrafine fibrous membranes fabricated from aqueous colloids of neat globular SPs, the major byproducts of under-utilized edible oil and biodiesel. The natural polyampholyte origin, amphoterism, and green processing make these fibrous materials unique and versatile for many potential applications involving both anionic and cationic species.

Amphiphilic Protein Microfibrils from Ice-Templated Self-Assembly and Disassembly of Pickering Emulsions.

Amphiphilic protein microfibrils have been generated for the first time by ice-templated self-assembly of aqueous globular protein colloids and subsequent selective disassembly in polar solvents like MeOH, EtOH, acetone, and dimethylformamide. Semicrystalline microfibrils, ca. 1.2 µm wide and 45-70 µm long, produced from soy proteins are excellent amphiphiles, which are capable of stabilizing both high-internal-phase o/w and w1/o/w2 double emulsions as well as retaining amphiphilicity even with surface-bound lipophiles and electrophiles. This ice-templated self-assembling and polar solvent disassembling approach is applicable to other legume proteins, such as pea proteins, and is scalable to process globular proteins into amphiphilic microfibrils for Pickering emulsions in many potential applications including food, pharmaceuticals and skin care.

Photonic Thin Films Assembled from Amphiphilic Cellulose Nanofibrils Displaying Iridescent Full-Colors.

Self-assembly of nanoparticles (NPs) to form structural colors offers promising opportunities for developing electronic, optoelectronic, and magnetic devices. In this regard, we reported co-assembly of cellulose nanofibrils (CNFs) and graphene to produce colored thin films. We demonstrated that biomimetic iridescent "peacock feather"-like full-color thin films can be generated by simple evaporation of aqueous suspensions on a surface tension confined, optically symmetric indium tin oxide-coated polyethylene terephthalate substrate. Amphiphilic CNFs serve dual functions to attract hydrophobic graphene via van der Waals interactions and to disperse hydrophilically and anionically CNF-tethered graphene while regulating surface tension to induce capillary and Marangoni flows in the force fields and construct thickness variation during dewetting. These CNF-graphene thin films exhibit full-color patterns and function as tunable light and moisture actuators. This approach has high potential to be applied to assemble other metal or metal oxide NPs for fast, simple, and robust fabrication without involving any complex lithography and external fields.

Tunable surface wettability and pH-responsive 2D structures from amphiphilic and amphoteric protein microfibrils.

Two dimensional films and paper-like structures (60-170 µm thick) have been facilely fabricated by casting ethanolic dispersions of amphiphilic and amphoteric protein microfibrils (ca. 1.3 µm width; 53 µm length) under controlled temperatures and moisture levels. Surface hydrophilicity or hydrophobicity can be easily tuned by the abillity of the highly responsive microfibers to self-organize at the interface to mimic the hydrophilicity or hydrophobicity of cast substrates. For instance, surfaces cast on hydrophobic polystyrene or Teflon were moderately hydrophobic with water contact angles (WCAs) of 54°-71° while those on hydrophilic glass or exposed to air were hydrophilic (WCAs: 5°-10°). Thin film dried in the presence of moisture (60% RH) at 65 °C had the highest crystallinity (CrI: 56%) and ß structure (64%), including 48% ß-sheet form, and exhibited moisture-responsive T g, pH-responsive planar swelling, and excellent wet resiliency in extremely acidic (pH = 0) to basic (pH = 10) conditions. The pH-dependent release of highly water-soluble cationic methylene blue bound to protein microfibril (SPMF) films attests to their amphoterism and demonstrates the applicability of such 2D structures for pH-dependent controlled release of other cationic and anionic species. Such versatility of amphiphilic and amphoteric protein microfibrils can be engineered into 2D structures with tunable surface hydrophilicity and hydrophobicity, moisture- and pH-responsive behaviors and controlled release capabilities.

Tunable dialdehyde/dicarboxylate nanocelluloses by stoichiometrically optimized sequential periodate-chlorite oxidation for tough and wet shape recoverable aerogels.

Sequential periodate-chlorite (PC) oxidation has been optimized stoichiometrically according to the non-crystalline content in cellulose to generate a variety of versatile C2,C3 dialdehyde/dicarboxylate nanocelluloses (NCs) while economizing chemical and shear force inputs. The robust primary sodium periodate (NaIO4) oxidation not only regioselectively cleaved the C2-C3 carbon bond to oxidize the vicinal hydroxyls to aldehydes, but also governed the lengths of NCs, i.e., cellulose nanofibrils (PC-CNFs) at near-equal NaIO4 to non-crystalline anhydroglucose unit (AGU) stoichiometry and cellulose nanocrystals (PC-CNCs) at a doubled ratio. Secondary sodium chlorite (NaClO2) oxidation facilely converted C2,C3 dialdehydes to dicarboxylates and, upon deprotonation, facilitated defibrillation to NCs, irrespective of extents of carboxylation or charges. The optimal 0.5 : 1 NaIO4/AGU and 1 : 1 NaClO2/AGU oxidation produced highly uniform 1.26 nm thick, 3.28 nm wide, and ca. 1 µm long PC-CNFs with tunable surface aldehyde (0.71-0.0 mmol g-1) and carboxylate (0.64-1.35 mmol g-1) content at 94-98% yields. The C2-C3 glucosidic ring opening and oxidation along the 110 or 11̄0 crystalline surfaces increased the heterogeneity of the hydrophilic surfaces and flexibility of PC-CNFs to influence their self-assembling into fibrils and amphiphilic superabsorbent aerogels. The ultra-light (ρ = 10.3 mg cm-3) aerogels showed an ultra-high dry specific compression modulus (50.2 kPa mg-1 cm-3) and specific stress (8.2 kPa mg-1 cm-3 at 0.8 strain), cyclic wet compressive behavior, and excellent water-activated shape recovery following 0.8 strain dry compression.

Aqueous exfoliated graphene by amphiphilic nanocellulose and its application in moisture-responsive foldable actuators.

Graphene is a promising material for diverse applications, such as in composites, optoelectronics, photovoltaic cells, and energy storage devices. However, high-yielding liquid exfoliation of good-quality graphene in high concentrations remains a challenge. In this study, amphiphilic 2,2,6,6-tetramethylpiperidin-1-yl-oxyl (TEMPO)-mediated cellulose nanofibrils (CNFs) were demonstrated in robust aqueous exfoliation of graphite into high quality graphene in high yields and stable dispersions with graphene concentration up to 1 mg mL-1. Over 50% of graphene flakes exfoliated were 3 layers or less, of which ca. 5% were monolayer, and another 47% were multilayers, leaving only 3% as un-exfoliated graphitic platelets. Outstanding yields up to 84.2% were achieved at an optimized 0.2 g g-1 graphite : CNF feed ratio. The dispersed graphitic flakes are stabilized by Coulomb repulsion from the surface bound charged CNFs. Aqueous graphene suspensions stabilized by CNFs were easily vacuum filtered into nanopapers that exhibited rapid moisture triggered motion and spontaneous recovery in the absence of moisture, resembling actions of biological motor cells in "shame plant" leaves. Such unique moisture responsive behavior is attributed to the highly accessible, charged CNF surfaces and the recovery is due to the inherently hydrophobic graphene. This facile aqueous exfoliating approach using amphiphilic CNFs as multi-functional exfoliating, dispersing and structural-forming agents for moisture-responsive graphene nanopaper opens up a large-area of potential applications toward biologically inspired sensors and actuators.

Conductive Polymer Protonated Nanocellulose Aerogels for Tunable and Linearly Responsive Strain Sensors.

Strong and highly conductive aerogels have been assembled from cellulose nanofibrils (CNFs) protonated with conductive poly(3,4-ethylene dioxythiophene)/poly(styrene sulfonate) (PEDOT/PSS) complex at equal mass or less. Protonating CNF surface carboxylates and hydrogen-bonding CNF surface carboxyls with PSS in PEDOT/PSS generated PEDOT/PSS/CNF aerogels that were up to ten times stronger while as conductive as neat PEDOT/PSS aerogel, attributed to the transformation of PEDOT benzoid structure to the more electron transfer-preferred quinoid structure. Ethylene glycol vapor annealing further increased the conductivity of PEDOT/PSS/CNF aerogels by 2 orders of magnitude. The poly(dimethylsiloxane) (PDMS)-infused conductive PEDOT/PSS/CNF aerogel (70 wt % CNF) transform a resistance-insensitive PDMS-infused PEDOT/PSS aerogel (gauge factor of 1.1 × 10-4) into a stretchable, sensitive, and linearly responsive strain sensor (gauge factor of 14.8 at 95% strain).

Dual Wet and Dry Resilient Cellulose II Fibrous Aerogel for Hydrocarbon-Water Separation and Energy Storage Applications.

Cellulose fibrous aerogels have been fabricated by a facile and aqueous process that disintegrated electrospun cellulose fibers (ECFs) and reassembled via freezing/freeze-drying with significantly improved dry resiliency and spontaneous 89% shape recovery from ca. 70% compressive strain. Owing to the resilient and 200-300 nm wide ECFs, the cellulose fibrous aerogels exhibited excellent dual dry and wet resiliency as well as improved pore accessibility. The fibrous cellular walls interconnect the aerogel pore structure to allow extraordinary liquid absorption capacity up to 373 g/g, accounting for 95% of the theoretical absorption capacity. Both highly dry resilient and absorbent properties of the ECF aerogel are highly advantageous for hydrocarbon/oil contamination removal and for hydrocarbon/water separation applications. In addition, the ECF aerogel could be carbonized into carbon aerogel in supercapacitors for energy storage.

Adsorption and desorption of cationic malachite green dye on cellulose nanofibril aerogels.

Ultra-light aerogels have been assembled from cellulose nanofibrils into hierarchically macroporous (several hundred µm) honeycomb cellular structure surrounded with mesoporous (8-60nm) thin walls. The high specific surface (193m2/g) and surface carboxyl content (1.29mmol/g) of these aerogels were demonstrated to be highly capable of removing cationic malachite green (MG) dye from aqueous media. The rapid MG adsorption was driven by electrostatic interactions and followed a pseudo-second-order adsorption kinetic and monolayer Langmuir adsorption isotherm. At a low 1:5mg/mL aerogel/MG ratio, both initial MG adsorption rate (2.3-59.8mgg-1min-1) and equilibrium adsorption capacity (53.0-203.7mgg-1) increased with increasing initial MG concentrations from 10 to 200mg/L, reaching a maximum adsorption of 212.7mgg-1. The excellent dye removal efficiency was demonstrated by complete MG removal through four repetitive adsorptions at a low 1:5mg/mL aerogel/MG ratio and 10mg/L dye concentration as well as 92% MG adsorption in a single batch at one order of magnitude higher10:5mg/mL aerogel/MG ratio and 100mg/L dye concentration. The adsorbed MG in aerogels could be desorbed in aqueous media by increasing ionic strength, demonstrating facile recovery of both dye and aerogel as well as the robust capability of this aerogel for repetitive applications.