Sequential Oxidation on Wood and Its Application in Pb2+ Removal from Contaminated Water

Priyanka R Sharma,Marc Nolan,Benjamin S Hsiao,Wenqi Li,Sunil K Sharma,Lakshta Kundal

doi:10.3390/polysaccharides2020017

Abstract

Raw wood was subjected to sequential oxidation to produce 2,3,6-tricarboxycellulose (TCC) nanofibers with a high surficial charge of 1.14 mmol/g in the form of carboxylate groups. Three oxidation steps, including nitro-oxidation, periodate, and sodium chlorite oxidation, were successfully applied to generate TCC nanofibers from raw wood. The morphology of extracted TCC nanofibers measured using TEM and AFM indicated the average length, width, and thickness were in the range of 750 ± 110, 4.5 ± 1.8, and 1.23 nm, respectively. Due to high negative surficial charges on TCC, it was studied for its absorption capabilities against Pb2+ ions. The remediation results indicated that a low concentration of TCC nanofibers (0.02 wt%) was able to remove a wide range of Pb2+ ion impurities from 5–250 ppm with an efficiency between 709–99%, whereby the maximum adsorption capacity (Qm) was 1569 mg/g with R2 0.69531 calculated from Langmuir fitting. It was observed that the high adsorption capacity of TCC nanofibers was due to the collective effect of adsorption and precipitation confirmed by the FTIR and SEM/EDS analysis. The high carboxylate content and fiber morphology of TCC has enabled it as an excellent substrate to remove Pb2+ ions impurities.

Highlights

Cellulose is a naturally occurring, renewable, inexpensive, and environmentally friendly material that exhibits properties that make it a viable biomaterial [1]
This study looks to produce TCC nanofibers, which we have hypothesized will lead to a higher concentration of carboxylate groups than the 6CC nanofibers because, in TCC, all three active hydroxyl groups will randomly transform to carboxylate groups (COO- ) or ionic sites
It was observed that the OH stretching peak at 3328 cm−1 in 6CC and TCC became much sharper than that in raw wood

Summary

Introduction

Cellulose is a naturally occurring, renewable, inexpensive, and environmentally friendly material that exhibits properties that make it a viable biomaterial [1]. It is the most abundant biopolymer on Earth, and approximately 1.5 trillion tons of cellulose biomass are produced on an annual basis [2]. It is comprised of β-(1-4)-linked D-glucose units and are linked at the C1 and C4 positions of the anhydroglucose units (AGUs). When carboxycellulose fibers are extracted in nanoscale ranges (e.g., nanofibers (L ≥ 1000 nm, W ≥ 10 nm), nanocrystals

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Results

Conclusion