Grafting nanocellulose with diethylenetriaminepentaacetic acid and chitosan as additive for enhancing recycled OCC pulp fibres

This paper develops a novel paper additive for effectively recycling old corrugated container (OCC) by functionalizing nanocellulose (NC) with diethylenetriaminepentaacetic acid (DTPA) and chitosan (CS), and investigate the reinforcing mechanisms and effect of the developed additive on the physical properties of recycled OCC pulp handsheets. The tensile, tear and burst index, air permeability, tensile energy absorption (TEA), and drainage performance of the recycled OCC handsheets are examined. Fourier transform infrared FTIR) spectroscopy, thermal gravimetric analysis (TGA) and scanning electron microscopy (SEM) are used for the chemical and microstructure characterization of both NC based additives and paper from recycled OCC pulp. The results show that functional groups on the NC based additive, such as carboxyl, amino and hydroxyl groups, can bond with the hydroxyl groups on the recycled OCC fibres to generate a chemical bond. This leads to an increase in the crosslinks and bonding area between the fibres, which increases their tensile strength and improves their recycling rate. SEM shows that the paper with NC based additives had tighter inter-fibre bonds and smaller paper pore structure. Addition of 0.3% NC-DTPA-CS additive results in optimal properties of the recycled OCC paper with an increase by 31.64%, 22.28% and 36.6% of tensile index, tear index, burst index respectively, and the air permeability decreases by 36.92%. Graphical Abstract

Grafting Nanocellulose With Diethylenetriaminepentaacetic Acid and Chitosan As Additive for Enhancing Recycled OCC Pulp Fibres

This paper is to develop a novel paper additive for effectively recycling old corrugated container (OCC) by functionalizing nanocellulose (NC) with diethylenetriaminepentaacetic acid (DTPA) and chitosan (CS), and investigate the reinforcing mechanisms and effect of the developed additive on the physical properties of recycled OCC pulp handsheets. The tensile, tear and bursting strength, whiteness, air permeability, tensile energy absorption of the recycled OCC handsheets are examined. Fourier transform infrared FTIR) spectroscopy, thermal gravimetric analysis (TGA) and scanning electron microscopy (SEM) are used for the chemical and microstructure characterization of both NC based additives and recycled OCC pulp paper. The results show that the functional groups, such as carboxyl, amino and hydroxyl groups on the NC based additives, can combine with the hydroxyl groups on the recycled OCC fibres to generate chemical bonds, which increase the crosslinks between fibres as well as the bonding area, thus enhancing their tensile strength and improving their recycling rate. SEM shows that the paper with NC based additives had tighter inter-fibre bonds and smaller paper pore structure. Addition of 0.2% NC-DTPA-CS additive results in optimal properties of the recycled OCC paper with an increase by 32%, 188%, 19% and 35% of tensile strength, tearing degree, breaking resistance and air permeability respectively.

OPTIMIZATION OF DITHIONITE BLEACHING OF HIGH YIELD BAGASSE PULP

Non-wood raw materials are an essential fiber source in regions where forest resources are limited. Therefore, chemi-mechanical high-yield bagasse pulp was prepared and then bleached with a dithionite bleaching agent. One- and two-stage bleaching of the pulp was carried out by using sodium dithionite (Y) as a sole bleaching agent, or after bleaching with hydrogen peroxide to achieve high brightness for the prepared pulp. Different parameters, such as consistency, concentration, temperature, time and pH were investigated. The effect of various additives, such as diethylenetriaminepentaacetic acid (DTPA) as chelating agent or Zn compounds and hexamethylenetetramine to stabilize the bleaching solution, was studied. The effect of dissolved oxygen in liquor was also considered.

Influence of Physicochemical Properties and Parent Material on Chromium Fractionation in Soils

Chromium is an element that possess several oxidation states and can easily pass from one to another, so its behavior in soils is very complex. For this reason, determining its fate in the environment can be difficult. In this research work we tried to determine which factors affect the chromium fractionation in natural soils, conditioning chromium mobility. We paid special attention to the parent material. For this purpose, extraction experiments were carried out on spiked soils incubated for 50–60 days, using H2O, CaCl2 and diethylenetriaminepentaacetic acid (DTPA). The most efficient extraction rate in all soils was achieved using water, followed by CaCl2 and DTPA. We obtained models with an adjusted R2 of 0.8097, 0.8471 and 0.7509 for the H2O Cr, CaCl2 Cr and DTPA Cr respectively. All models were influenced by the amount of chromium added and the parent material: amphibolite and granite influenced the amount of H2O Cr extracted, and schist affected the other two fractions (CaCl2 and DTPA). Soil texture also played an important role in the chromium extraction, as well as the amounts of exchangeable aluminum and magnesium, and the bioavailable phosphorus. We concluded that it is possible to make relatively accurate predictions of the behavior of the different Cr fractions studied, so that optimized remediation strategies for chromium-contaminated soils can be designed on the basis of a physicochemical soil characterization.

Novel Strategy for Diagnosis of Focal Nodular Hyperplasia Using Gadolinium Ethoxybenzyl Diethylenetriaminepentaacetic Acid: Enhanced Magnetic Resonance Imaging and Magnetic Resonance Elastography

Focal nodular hyperplasia (FNH) is the second most frequent benign liver tumor, and it is a fiber-rich stiff lesion. Typically, FNH can be diagnosed by imaging without biopsy. However, liver biopsy and diagnostic resection may be required to differentiate atypical FNH from other liver tumors, such as hepatocellular adenoma (HCA). Therefore, improved noninvasive diagnostic methods are needed. We experienced 2 cases where combination of magnetic resonance elastography (MRE) and gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) helped diagnose FNH. A 36-year-old woman and 17-year-old boy with liver tumors measuring 40 mm in diameter each showed hypointense nodule centers, indicating a central scar, surrounded by hyperintense signals during the hepatobiliary phase of Gd-EOB-DTPA-enhanced MRI. To rule out HCA, we performed MRE and liver biopsy. On MRE, the mean stiffness of the mass was 11.6 kPa (mean stiffness of the background liver was 1.7 kPa) and 11.1 kPa (mean stiffness of the background liver was 2.4 kPa) in the first and second patients, respectively. Histological examination of both specimens showed CK7-positive bile-ductular proliferations, abundant fibrous tissue, and few Ki-67-positive cells. Based on these results, we diagnosed these tumors as FNH. Combination of Gd-EOB-DTPA-enhanced MRI and MRE can evaluate the character and stiffness of lesion and help in the diagnosis of FNH.