Synthesis and application of recyclable magnetic cellulose nanocrystals for effective demulsification of water in crude oil emulsions.

The development of eco-friendly, efficient, and economical demulsifiers for the demulsification of water in crude oil emulsion is one of the important issues in the petroleum industry. Demulsifiers with suitable performance in several demulsification methods are good choices for effective and economical demulsification. In this study, recyclable magnetic cellulose nanocrystals have been synthesized from cotton by a simple method and used in the demulsification of water in crude oil emulsions. Chemical and magnetic demulsification by magnetic cellulose nanocrystals has been investigated. In addition, the effects of time, temperature, and demulsifier concentration on the demulsification efficiency have been evaluated. According to the results, this demulsifier can be used as an effective demulsifier for both chemical and magnetic demulsification and displayed a demulsification efficiency of 100 % at 50 °C without a magnet and 90 % at 20 °C with a magnet. The chemical demulsification efficiency of Fe3O4 nanoparticles was investigated and it showed lower DE compared to magnetic cellulose nanocrystals. The recyclability tests of the demulsifier indicated that magnetic cellulose nanocrystals can be used up to 4 times. Finally, the demulsification mechanism and interfacial tension measurements revealed that this demulsifier reduced the interfacial tension between water and crude oil and increased the water droplet sizes.

High nitrate removal by starch-stabilized Fe0 nanoparticles in aqueous solution in a controlled system.

This study was conducted to investigate biodenitrification efficiency with starch-stabilized nano zero valent iron (S-nZVI) as the additional electron donor in the presence of S2O3 in aqueous solutions, under anaerobic conditions. The main challenge for nZVI application is their tendency to agglomeration, thereby resulting in loss of reactivity that necessitates the use of stabilizers to improve their stability. In this study, S-nZVI was synthesized by chemical reduction method with starch as a stabilizer. The synthesized nanoparticles were characterized by TEM, XRD, and FTIR. Transmission electron microscopy (TEM) image shows S-nZVI has a size in the range of 5-27.5 nanometer. Temperature and S-nZVI concentration were the important factors affecting nitrate removal. Biodenitrification increased at 35°C and 500 mg/L of S-nZVI, in these conditions, biodenitrification efficiency increased from 40.45 to 78.84%. Experimental results suggested that biodenitrification increased by decreasing initial nitrate concentration. In the bioreactor biodenitrification rate was 94.07% in the presence of S-nZVI. This study indicated that, Fe2+ could be used as the only electron donor or as the additional electron donor in the presence of S2O3 to increase denitrification efficiency.

Fischer-Tropsch synthesis with Fe/Cu/La/SiO2 nano-structured catalyst.

Nano-structure Fe2O3, CuO and La2O3 components were prepared by micro-emulsion method and then Fe/Cu/La/SiO2 nano-structure catalyst was prepared by mixing and re-slurring the mixture by tetraethylorthosilicate (TEOS). The catalyst composition was designated in term of the atomic ration as: 100Fe/5.64Cu/0.1La/19Si. Structural characterization of nano-structured Fe2O3, CuO and La2O3 components was performed by Transmission Electron Microscopy (TEM), powder X-ray diffraction, Temperature Programmed Reduction (TPR) techniques. Particle size for obtained components was about 20, 21.6 and 12.6 nm for Fe2O3, CuO and La2O3 respectively determined by using XRD pattern (Scherrer equation) and TEM images. Catalytic activity and product selectivity were conducted in a fixed-bed stainless steel reactor and compared with conventional iron catalyst. The results reveal that reducing particle size of catalyst increased the catalyst performance. Also, olefin/paraffin ratios decreased in comparison with conventional catalyst.

Recent advances in nanoparticle preparation by spray and micro-emulsion methods.

Micro- and nano-sized metal, semiconductor, pharmaceutical, and simple or complex ceramic particles have numerous applications in the development of sensors, thermal barrier coatings, catalysts, pigments, drugs, etc. The challenges include controlling the particle size, size distribution, particle crystallinity, morphology and shape, being able to use the nanoparticles for a given purpose, and to produce them from a variety of precursors. There are several methods to produce nanoparticles, each suitable for a range of applications. In this article, two methods that are receiving increasing attention are considered: spray and microemulsion methods. Spray techniques are single-step methods of producing a broad spectrum of simple to multicomponent functional micro and nanoparticles and quantum dots. Microemulsion is a wet chemistry method. A micro-emulsion system consists of aqueous domains, called reverse micelles, dispersed in a continuous oil phase. In this article, the above mentioned methods of nanoparticle production are introduced and recent advances, research directions and challenges, and the pertinent patents are reviewed and discussed.