2017, Volume 63(67), Issue 3 (September)

Contents

pages 1- 8    Download

Photocatalytic and Photo-Fenton Degradation of Ibuprophen under Solar Light Irradiation

MIHAELA DARIE, "Gheorghe Asachi" Technical University of Iaşi, Faculty of Chemical Engineering and Environmental Protection, ddariemihaela@yahoo.com
GABRIELA CARJA,
"Gheorghe Asachi" Technical University of Iaşi, Faculty of Chemical Engineering and Environmental Protection, gcarja@ch.tuiasi.ro

pages 9 - 21    Download
Abstract
In this work, the degradation of pharmaceutical agent ibuprofen by photocatalysis and photo-Fenton catalysis, using artificial visible light irradiation and H2O2 as Fenton reagent, was carried out. Two efficient Fe/LDHs photocatalysts with different iron content were fabricated. First, the LDH precursor with Zn2+ and Al3+ as di- and trivalent brucite-like cations (Zn2+/Al3+ = 3/1) was obtained by co-precipitation method and denoted as Zn3Al. Then, by the structural reconstruction of the calcined Zn3Al in aqueous solution of FeSO4∙7H2O, two Fe/LDH- based nanocomposites were obtained and denoted as Fe(1%)Zn3Al and Fe(4%)Zn3Al. The structural and optical properties of the samples were studied by XRD, FTIR and UV-Vis techniques. The photocatalytic tests were performed using a solar simulator as irradiation source. Photocatalytic results showed that the novel catalysts is efficient for the ibuprofen degradation. A remarkable enhancement of Ibuprofen degradation was obtained in the case of photo-Fenton process, up to 89% by Fe(1%)Zn3Al nanocomposite. Increasing the content of Fe in the catalysts showed an insignificant effect in enhancing the catalyst efficiency for ibuprofen removal.
Keywords: photocatalyst; ibuprofen; photo-Fenton; solar photodegradation.

Opportunity to Apply Thermal Decomposition of Spruce Bark after Extractives Recovery

OANA ALEXANDRA PĂTRĂUŢANU, "Gheorghe Asachi" Technical University of Iaşi, Faculty of Chemical Engineering and Environmental Protection
MIHAI BREBU,
"Petru Poni" Institute of Macromolecular Chemistry, Iaşi
VALENTIN I. POPA,
"Gheorghe Asachi" Technical University of Iaşi, Faculty of Chemical Engineering and Environmental Protection
IRINA VOLF,
"Gheorghe Asachi" Technical University of Iaşi, Faculty of Chemical Engineering and Environmental Protection, iwolf@tuiasi.ro

pages 23 - 33     Download
Abstract
The work explores the possibility to use the thermal decomposition of spruce bark (Picea Abies) in a second biorefinery flow sheet. Spruce bark was characterised and humidity, ash, hemicelluloses, cellulose and lignin content were determined. For the recovery of extractives two procedures were applied: the biomass was extracted with toluene-ethanol mixture using a conventional extraction and a 70% ethanol solution was used in an ultrasound assisted extraction process. In both cases the solid waste was subjected to pyrolysis conducted at 550°C under relatively low heating rate of 10°C/min. The aqueous phase was analysed by GC-MS. Similarities and some differences are highlighted by the GC-chromatograms and NP-gram characterisation, depending on the extraction procedures applied.
Keywords: biomass; extractives; pyrolysis; GC-MS; NP-gram.

Cellulosic Fibers from Miscanthus   

CRISTIAN IONUȚ SANDU, "Gheorghe Asachi" Technical University of Iaşi, Faculty of Chemical Engineering and Environmental Protection
ANA-MARIA CHEȘCĂ, "Gheorghe Asachi" Technical University of Iaşi, Faculty of Chemical Engineering and Environmental Protection
ADRIAN CĂTĂLIN PUIȚEL, "Gheorghe Asachi" Technical University of Iaşi, Faculty of Chemical Engineering and Environmental Protection
DAN GAVRILESCU, "Gheorghe Asachi" Technical University of Iaşi, Faculty of Chemical Engineering and Environmental Protection, gda@tuiasi.ro

pages 35 - 46      Download
Abstract
Miscanthus is an important biomass crop and has an important role in the sustainable production of renewable fuels and chemicals. It is currently used as a source of heat and electricity, or converted into biofuel products. There are many possibilities to valorize Miscanthus crops: combustion, gasification and pyrolysis for energy; liquefaction and hydrolysis for chemicals; delignification for cellulosic fibers. Chemical composition of Miscanthus is encouraging regarding its cellulose and lignin content, making them suitable for delignification. Miscanthus pulp can be obtained by usual delignification processes, among them soda cooking being very attractive. Pulps having different yields and lignin content were obtained by suitable choosing of the cooking parameters: NaOH addition, time and temperature. The strength properties of pulp mainly depended on its lignin content. Lignin-rich pulps show high compressive strength, being appropriate in paper manufacturing for corrugated board production.
Keywords: Miscanthus crop; soda cooking; chemical pulp; pulp properties; paper.

Biosorption Potential of the Main Fractions Separated from Peat (Poiana Stampei, Romania)

SILVIA PRUTEANU, "Gheorghe Asachi" Technical University of Iaşi, Faculty of Chemical Engineering and Environmental Protection
LAURA BULGARIU, "Gheorghe Asachi" Technical University of Iaşi, Faculty of Chemical Engineering and Environmental Protection, lbulg@ch.tuiasi.ro
MARIA GAVRILESCU,  "Gheorghe Asachi" Technical University of Iaşi, Faculty of Chemical Engineering and Environmental Protection

pages 47 - 56      Download
Abstract
In this study it was investigated the separation possibility of the main organic fraction of peat (Poiana Stampei, Romania), consisting in humic substances and cellulosic waste, for its use as biosorbents in the removal process of Cu(II) ions from aqueous solution. In order to separate the two fractions, the peat was treated with sodium hydroxide solutions of different concentrations (0.1 – 4.0 N), at two different temperatures (20 and 50°C) for 3 h of mixing. In this way, only the solubilisation of humic substances from the peat composition takes place, which can be separated from cellulosic waste by filtration. After filtration, the humic substances were re-precipitated in strong acid media (pH < 1.0), and then both obtained fractions were washed and dried in air. The efficiency of separation process was evaluated in each case. All resulted fractions were used as biosorbents for the removal of Cu(II) ions from aqueous solution. The experimental results have shown that the fractions separated by the treatment of peat with 2N NaOH solution at 50°C exhibit the highest biosorption capacities.
Keywords: peat; humic substances; cellulosic waste; Cu(II) ions; biosorption.

Pb(II) Removal from Aqueous Solutions by Using Wastes of Pinus Strobus Bark

LAVINIA TOFAN, "Gheorghe Asachi" Technical University of Iaşi, Faculty of Chemical Engineering and Environmental Protection
CARMEN PĂDURARU, "Gheorghe Asachi" Technical University of Iaşi, Faculty of Chemical Engineering and Environmental Protection, cpadur2005@yahoo.com
ION BUNIA, "Gheorghe Asachi" Technical University of Iaşi, Faculty of Chemical Engineering and Environmental Protection
ROXANA LAURA MIHĂILESCU AMĂLINEI, "Gheorghe Asachi" Technical University of Iaşi, Faculty of Chemical Engineering and Environmental Protection
ANCA MIRON, "Gheorghe Asachi" Technical University of Iaşi, Faculty of Chemical Engineering and Environmental Protection

pages 57 - 70      Download
Abstract
The influence of significant operational parameters on the Pb(II) sorption process by Romanian Pinus strobus has been studied in batch conditions. The uptake of Pb(II) from solutions with different initial concentrations of Pb(II) increased progressively with increasing initial pH from 2 to 5-5.5. The percent removal of Pb(II) varied from 84% to 98% for an increase of bark waste dose to 4 at 60 g/ L. The sorption isotherm studies clearly indicated that the sorptive behavior of Pb(II) ions on Romanian Pinus strobus bark under study satisfies not only the Langmuir assumptions, but also the Freundlich assumption. The calculated values for the isothermal thermodynamic parameters show that Pb(II) ions retention by pine bark is a spontaneous process of endothermic and chemical nature. The sorption kinetics for Pb(II) ions removal from aqueous solutions was very well described by pseudo-second order model.
Keywords: Pinus strobus; bark; sorption; waste; lead.