Showing papers by "Abd El-Aziz A. Said published in 2023"

An approach for application of ozone bleaching and nano‐filler loading on quality of papermaking from sorghum bagasse as a promise alternative non‐wood fiber

Abstract: Over the past years, non-stop research and development has continued to find the most suitable bleaching sequence for each source of fibrous raw materials, both wood and non-wood, by improving mixing technology. In this work, the role of ozone bleaching and nano-filler loading on the quality of papermaking from sorghum bagasse as an alternative available agriculture residue in Egypt was studied. We bleached the sorghum Kraft pulp using D0EOD1 and ZEOD sequences to achieve a final high brightness and suitable mechanical strength. The quality of the pulp obtained is proved to be excellent for paper industry. CaCO3 nano-filler was applied on bleached pulp sheets in order to decrease the production costs through increasing filler loading. The FTIR spectrum of this filler loaded on the pulp indicates the existence of some kind of bonds between them. In addition, it was observed that the particle size was reduced after the milling process. The nano-filler significantly enhanced the retention and consequently all the paper optical properties. Addition of nano-filler loading leads to improving brightness, opacity, scattering coefficient, and acceptable mechanical strength of sheet formation needed for papermaking. It is of interest to note that adopting the ZEOD sequence gave a brightness increase from 86 ISO in case of DoEOD1 to 90 ISO. Furthermore, the paper sheets filled with the nano-filler, according to this sequence, improved the brightness to be 94.6 ISO, a value higher than that produced by the standard commercial filler of 93.3 ISO.

Zirconia Incorporated Aluminum Phosphate Molecular Sieves as Efficient Microporous Nano Catalysts for the Selective Dehydration of Methanol into Dimethyl Ether

Abstract: Abstract Annually, a growing demand was noted for replacing petroleum fuels with second-generation eco-friendly fuels like dimethyl ether (DME). Methanol dehydration into DME process has been considered as one of the potential pathways for the manufacture of a clean fuel. However, stable, and active catalyst is exceedingly requisite for generation of DME particularly at reasonably low temperature. In the current study, zirconia incorporated AlPO 4 tridymite microporous molecular sieve catalysts were fabricated by a hydrothermal method in the presence of triethylamine (TEA) as a structure directing agent. The catalysts were characterized by X-ray diffraction (XRD), energy dispersive X-ray (EDX), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and N 2 -sorption assessments. Catalysts’ acidity was estimated by decomposition of isopropanol, pyridine and dimethyl pyridine chemisorption, and pyridine-TPD. Results revealed that catalysts surfaces composed acid sites of Brønsted nature and of weak and medium strengths. Activity results showed that 1 wt% H 2 SO 4 modified zirconia incorporated AlPO 4 -TRI catalyst calcined at 400 °C presented the best activity with a conversion of 89% and a 100% selectivity into DME at 250 °C. The significant catalytic activity is well-connected to the variation in BET-surface area, acidity, and activation energy of methanol dehydration. The catalysts offered long-term stability for 120 h and could be regenerated with almost the same activity and selectivity. Graphical Abstract

The catalytic performance of FexMn1-xWO4 as novel wolframite-type nanocatalysts for the selective dehydration of methanol into dimethyl ether

Abstract: Selective production of dimethyl ether (DME), as a second-generation biofuel, under mild green conditions is still a challenge. Herein, FexMn1-xWO4 wolframite-type materials were proposed for the first time as efficient, selective, and stable catalysts towards methanol dehydration into DME. A simple one-step co-precipitation approach was used to fabricate the nanocomposites, and their catalytic performances were evaluated in comparison to earlier studies and to the commercial γ-Al2O3 in terms of activity. The catalysts’ structure, morphology, and porosity were identified by XRD, XPS, FTIR, TEM, and N2-sorption analyses. Results of XRD and XPS confirmed the successful synthesis of FexMn1-xWO4 catalysts. Acidity of these nanocomposites were greatly influenced with the variation in x-value, calcination temperature, and doping with SO42−. The Brønsted characters of the acid sites and their weak and medium strength were investigated from PY-FTIR, chemisorption of basic probes and pyridine-TPD. The variation of the catalytic activities of these nanocomposites was strongly correlated to the variation in the catalyst acidity. The catalytic activity results indicated that Fe0.5Mn0.5WO4 catalyst calcined at 500 °C and modified with 5 wt.% of SO42- is the most effective nanocomposite with conversion values of 86 and 90% at reaction temperatures of 250 and 275 °C, respectively and all of 100% DME selectivity. The remarkable enhancement in the catalytic activity due to the doping with SO42- is attributed to the inductive effect of S = O group created on the catalyst surface. This nanocomposite could be regenerated many times with nearly the same efficiency and selectivity. Moreover, it offered a long-term stability (∼120 h) towards DME production.