Wyniki wyszukiwania - BazTech

1

Rigid polyurethane foam composites with nut shells

Leszczyńska Milena, Ryszkowska Joanna, Szczepkowski Leonard

Polimery

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2020

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T. 65, nr 10

728--737

EN

Composites of rigid polyurethane foams were manufactured using ground peanut, hazelnut, walnut and pistachio shells. The aim of this study was the development of environmentally-friendly materials as well as investigation of the influence of the chemical structure, size and morphology of the filler particles on the processing parameters of the developed foams as well as their structure and physico-mechanical and thermal properties. The used fillers were precisely characterised, the viscosity of the polyol premixes have been examined and the characteristic times of the foaming processes have been investigated. The developed materials were studied using the differential scanning calorimetry, thermogravimetry, scanning electron microscopy, infrared spectroscopy and by determination of their apparent density, friability, water absorption and dimensional stability. The presented research results indicate that the agro-food industry waste could be a valuable source of raw materials for the production of rigid polyurethane foam composites.

PL

Kompozyty sztywnych pianek poliuretanowych wytwarzano z zastosowaniem rozdrobnionych łupin orzechów: ziemnych, włoskich, laskowych oraz pistacjowych. Celem pracy było otrzymanie materiałów przyjaznych dla środowiska oraz określenie wpływu budowy chemicznej, wymiarów cząstek i morfologii napełniaczy roślinnych na parametry przetwórcze mieszanek oraz na strukturę i właściwości fizyko-mechaniczne i termiczne wytworzonych pianek. Szczegółowo scharakteryzowano zastosowane napełniacze, określono lepkość przedmieszek poliolowych oraz czasy charakterystyczne dla procesu spieniania. Analizy wytworzonych materiałów dokonano z zastosowaniem różnicowej kalorymetrii skaningowej, termograwimetrii, skaningowej mikroskopii elektronowej, spektroskopii w podczerwieni, a także na podstawie wyznaczonej gęstości pozornej, kruchości, chłonności wody i stabilności wymiarowej. Przedstawione wyniki badań wskazują na duże możliwości wykorzystania odpadów przemysłu rolno-spożywczego do wytwarzania kompozytów sztywnych pianek poliuretanowych.

2

The effect of nut shell addition on the permeability of a crushed gold ore

Yilmaz S., Sirkeci A. A., Bilen M., Yigit I., Kizgut S.

Physicochemical Problems of Mineral Processing

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2018

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Vol. 54, iss. 2

467--475

EN

In this study, variations in permeability of a gold ore by nut shell addition was studied. Ore particle size, nut shell size and volume fraction in the ore were the parameters investigated. Permeability is an important issue in heap leach operations considering the processing duration. Particularly below 6 mm particle size permeability is greatly hampered. Turkey is the leading country in the world in hazelnut production. Therefore, considerable amounts of nut shell are obtained as a by-product. Incerase in the permeability of a finely crushed ore will obviously enable an increase in the leaching efficiency. The finer the particle size the more the liberation of gold is yet the permeability is lower. Therefore, this study focuses on the possibility of improving the permeability of ore heaps with nut shell addition. Optimum amount of nut shell which should be added to the ore was found to be 5% by volume. It was found that the permeability of ore crushed below 2.36 mm considerably increased by the addition of nut shell below 18 mm.

3

The study of physicochemical properties of activated carbons obtained from nut shells

Doczekalska B., Marcinkowski M., Bartkowiak M., Katolik Z.

Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology

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2018

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No. 104

75--79

EN

In the paper activated carbons (AC) from three lignocellulosic materials: walnut shells (Juglans regia), pistachio shells (Pistacia vera) and peanut shells (Arachis hypogaea) were obtained. The following physicochemical properties of ACs were examined: content of oxygen surface functional groups by the Boehm method, porous structure by nitrogen sorption at -196oC and thermal resistance by thermogravimetric method. The activated carbons, formed during the KOH activation process, showed an acidic character. However, the use of sodium hydroxide as an activator, promoted the formation of alkaline groups. All activated carbons had a strongly developed surface area, above 1700 m2/g, and a high total pore volume. The largest SBET values had ACs from walnut shells, then from peanut shells and the smallest values had pistachio shells (for both activators). Most of obtained ACs were mesoporous.

4

Removal of chlorophenols from aqueous solutions by sorption onto walnut, pistachio and hazelnut shells

Kuśmierek K., Świątkowski A.

Polish Journal of Chemical Technology

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2015

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Vol. 17, nr 1

23--31

EN

The efficiency of walnut, pistachio and hazelnut shells to remove three monochlorophenols (2-CP, 3-CP and 4-CP) from aqueous solutions has been investigated. To describe the kinetic data pseudo-first and pseudo-second order models were used. The kinetics data were fitted better into the pseudo-second order model with the coefficient of determination values greater than 0.99. The k2 &ensp values increased in the order 4-CP < 3-CP < 2-CP. Sorption was also analyzed as a function of solution concentration at equilibrium. The experimental data received were found to be well described by the Freundlich isotherm equation. Effectiveness of chlorophenols removal from water on the walnut, pistachio and hazelnut shells was comparable. Individual differences in sorption of monochlorophenols were also negligible.