2021, Volume 67(71), Issue 1 (March)

Contents

pages 1- 8   Download

Removal of Nickel from Wastewater Using Ultrafiltration Membranes

GABRIELA CIOBANU, “Gheorghe Asachi” Technical University of Iași, Romania, “Cristofor Simionescu” Faculty of Chemical Engineering and Environmental Protection, gciobanu03@yahoo.co.uk
MARIA HARJA, “Gheorghe Asachi” Technical University of Iași, Romania, “Cristofor Simionescu” Faculty of Chemical Engineering and Environmental Protection

pages 9 - 16   Download
Abstract
In this study the asymmetric cellulose acetate membranes prepared by the phase inversion method were used for removal Ni2+ ions from wastewater. The membrane morphology was studied by Scanning Electron Microscopy (SEM) and the pore diameters have been determined by Bubble-point test (BPT). In the ultrafiltration experiments carried out in a flat-cell unit, the synthetic wastewater of nickel (10 mg/L) was used. The obtained results show that the flux and ion retention, increase with increasing pressure.
Keywords: membrane; cellulose acetate; ultrafiltration; nickel ions.

Effect of Metal Synergy and Loading on Binary W-Mo/HZSM-5 Catalyst for Non-Oxidative Conversion of Methane into Carbon and Petrochemicals

RONALD MUSAMALI, Durban University of Technology, Chemical Engineering department, South Africa, musamalironald@gmail.com
YUSUF ISA, Durban University of Technology, Chemical Engineering department, South Africa

pages 17 - 34   Download
Abstract
Processing of energy from fossil fuels is associated with emission of carbonaceous compounds. Therefore, non-oxidative conversion of methane into carbon and petrochemicals remediates emission of these greenhouse gases into the atmosphere. This present study demonstrates the development of stable, durable, and tunable binary catalyst systems comprising of W, &Mo supported on HZSM-5. The catalyst systems were synthesized by incipient wetness impregnation, characterized, and tested for non-oxidative methane conversion in a packed bed reactor. Reactor effluents were analyzed using gas chromatography. Based on the results obtained, competing reactions between different metal species, loading, and synergism influenced product distribution. Carburized molybdenum (Mo2C) on HZSM-5 zeolite alone exhibited low catalytic activity but on promotion with W, its activity increased tremendously. The reaction entailed dissociation of methane molecules on carburized Mo to form C2-species as primary intermediates which were further oligomerized into aromatics and higher hydrocarbons in the channels of HZSM-5 zeolite.
Keywords: Methane; non-oxidative; petrochemical; W-Mo/HZSM-5 catalyst.

Chemical Recycling of Wastepaper to Valuable Products

ALEKSANDRA MIKHAILIDI, St. Petersburg State University of Industrial Technologies and Design, St. Petersburg, Russia, amikhailidi@yahoo.com
NINA KOTELNIKOVA, Institute of Macromolecular Compounds, Russian Academy of Sciences, St. Petersburg, Russia

pages 35 - 42   Download
Abstract
The aim of the present study was to develop a method for preparing cellulose-based hydrogels (HGs) from waste paper (WP). Newsprint paper and various types of cardboard were subjected to pretreatments and then dissolved in DMAc/LiCl. Stable hydrogels were formed by spontaneous gelation from the solutions of WP. The properties of the HGs were examined both chemically and by FTIR, WAXS and SEM. FTIR confirmed the chemical purity of HGs. The structure of initial samples, HGs and freeze-dried HGs was characterised with WAXS. The cellulose I structure in the initial WP samples was totally disordered in solutions and partly recrystallized to the structure of cellulose II in freeze-dried HGs. According to SEM, the HGs revealed a random network with evenly distributed through pores of different sizes.
Keywords: waste paper; dissolution; hydrogels; structure; morphology.

Assessement of Crude Liquid Phase Resulted in Hydrothermal Carbonziation of Spruce Bark Wastes

IULIANA BEJENARI, “Gheorghe Asachi” Technical University of Iași, Romania, “Cristofor Simionescu” Faculty of Chemical Engineering and Environmental Protection
GABRIELA ANTOANETA APOSTOLESCU, “Gheorghe Asachi” Technical University of Iași, Romania, “Cristofor Simionescu” Faculty of Chemical Engineering and Environmental Protection
IRINA VOLF, “Gheorghe Asachi” Technical University of Iași, Romania, “Cristofor Simionescu” Faculty of Chemical Engineering and Environmental Protection, iwolf@tuiasi.ro

pages 43 - 52   Download
Abstract
This work aims to investigate the influence of process parameters on chemical composition of liquid phase resulted from hydrothermal carbonization of spruce bark (Picea abies). The thermal conversion of biomass was carried out at 200 and 240°C with a residence time of 2.5 and 5 h and a solid to liquid ratio of 1:10. Chemical characterization of liquid phase showed a presence of an important content of polyphenols and carbohydrates. The process parameters had a significant influence on chemical composition. Thus, an increase in temperature and residence time leads to a decrease of total polyphenols content and carbohydrates as well.
Keywords: bio-crude liquid; hydrothermal carbonization process; total polyphenols content; total reducing sugars content; spruce bark biomass.

Thermochromic Materials: Oxides with Applications in Intelligent Technologies

GABRIELA ANTOANETA APOSTOLESCU, “Gheorghe Asachi” Technical University of Iași, Romania, “Cristofor Simionescu” Faculty of Chemical Engineering and Environmental Protection
MIHAELA AURELIA VIZITIU, “Gheorghe Asachi” Technical University of Iași, Romania, “Cristofor Simionescu” Faculty of Chemical Engineering and Environmental Protection
CORINA CERNĂTESCU, “Gheorghe Asachi” Technical University of Iași, Romania, “Cristofor Simionescu” Faculty of Chemical Engineering and Environmental Protection
CLAUDIA COBZARU, “Gheorghe Asachi” Technical University of Iași, Romania, “Cristofor Simionescu” Faculty of Chemical Engineering and Environmental Protection
RAMONA ELENA TĂTARU-FĂRMUȘ, “Gheorghe Asachi” Technical University of Iași, Romania, “Cristofor Simionescu” Faculty of Chemical Engineering and Environmental Protection
NICOLAE APOSTOLESCU, “Gheorghe Asachi” Technical University of Iași, Romania, “Cristofor Simionescu” Faculty of Chemical Engineering and Environmental Protection, napostol@ch.tuiasi.ro

pages 53 - 64   Download
Abstract
Many types of smart materials have been studied and developed in the late years, due to their applications in industry (military, aerospace, medical, construction). The possibilities to develop environmentally friendly products (e.g. reducing the cost of building maintenance by using construction materials / smart windows, pollution reduction by using photo-catalytic active materials) are also studied. This type of intelligent materials also includes thermo-chromatic materials, able to change their color with temperature variation. This paper presents the phenomenon of thermo-chromatism, the main classes of thermo-chromatic materials, with emphasis on oxide materials, methods of obtaining, their applications and the current state of research in the field of mechanisms of producing thermo-chromatic phenomena.
Keywords: thermochromic materials; organic-inorganic hybrid systems; VO2.