Green Ambient-Dried Aerogels with a Facile pH-Tunable Surface Charge for Adsorption of Cationic and Anionic Contaminants with High Selectivity

• The fabrication of reusable, sustainable adsorbents from low-cost, renewable resources via energy efficient methods is challenging. This paper presents wet-stable, carboxymethylated cellulose nanofibril (CNF) and amyloid nanofibril (ANF) based aerogel-like adsorbents prepared through efficient and green processes for the removal of metal ions and dyes from water. The aerogels exhibit tunable densities (18-28 kg m-3), wet resilience, and an interconnected porous structure (99% porosity), with a pH controllable surface charge for adsorption of both cationic (methylene blue and Pb(II)) and anionic (brilliant blue, congo red, and Cr(VI)) model contaminants. The Langmuir saturation adsorption capacity of the aerogel was calculated to be 68, 79, and 42 mg g-1for brilliant blue, Pb(II), and Cr(VI), respectively. Adsorption kinetic studies for the adsorption of brilliant blue as a model contaminant demonstrated that a pseudo-second-order model best fitted the experimental data and that an intraparticle diffusion model suggests that there are three adsorption stages in the adsorption of brilliant blue on the aerogel. Following three cycles of adsorption and regeneration, the aerogels maintained nearly 97 and 96% of their adsorption capacity for methylene blue and Pb(II) as cationic contaminants and 89 and 80% for brilliant blue and Cr(VI) as anionic contaminants. Moreover, the aerogels showed remarkable selectivity for Pb(II) in the presence of calcium and magnesium as background ions, with a selectivity coefficient more than 2 orders of magnitude higher than calcium and magnesium. Overall, the energy-efficient and sustainable fabrication procedure, along with good structural stability, reusability, and selectivity, makes these aerogels very promising for water purification applications.

Ämnesord

NATURVETENSKAP  -- Kemi -- Materialkemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Materials Chemistry (hsv//eng)

TEKNIK OCH TEKNOLOGIER  -- Materialteknik -- Pappers-, massa- och fiberteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering -- Paper, Pulp and Fiber Technology (hsv//eng)

Nyckelord

Aerogels

Alginate

Aromatic compounds

Azo dyes

Calcium

Cellulose

Energy efficiency

Isotherms

Lead compounds

Magnesium

Metal ions

Nanofibers

Porosity

Reusability

Stability

Stripping (dyes)

Adsorption capacities

Ambients

Anionic contaminants

Brilliant Blue

Calcium and magnesiums

Cationic contaminants

Energy efficient

Methylene Blue

Model contaminant

Tunables

Adsorption

aerogel

cellulose nanofiber

chromium

congo red

lead

metal ion

nanofiber

water

anion

cation

chromium hexavalent ion

adsorption kinetics

Article

atmospheric pressure

atomic force microscopy

confocal microscopy

controlled study

freeze drying

ionization

isotherm

oxidation

pH

pore volume

scanning electron microscopy

surface charge

thermogravimetry

titrimetry

water management

zeta potential

chemistry

kinetics

water pollutant

Azo Compounds

Anions

Cations

Hydrogen-Ion Concentration

Water Pollutants

Chemical

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)