scholarly journals Recovery of Gold from Chloride Solution by TEMPO-Oxidized Cellulose Nanofiber Adsorbent

2019 ◽  
Vol 11 (5) ◽  
pp. 1406 ◽  
Author(s):  
Shila Jafari ◽  
Benjamin Wilson ◽  
Minna Hakalahti ◽  
Tekla Tammelin ◽  
Eero Kontturi ◽  
...  
Keyword(s):  
Chloride Solution ◽  
Cellulose Nanofibers ◽  
Precious Metals ◽  
Gold Recovery ◽  
Cellulose Nanofiber ◽  
Special Focus ◽  
Oxidized Cellulose ◽  
Chloride Leaching ◽  
Endothermic Process ◽  
Ferric Chloride Leaching

The goal of this study was to assess the sustainability of a modified cellulose nanofiber material for the recovery of precious gold from chloride solution, with a special focus on gold recovery from acidic solutions generated by cupric and ferric chloride leaching processes. TEMPO-oxidized cellulose nanofiber in hydrogel (TOCN), dry (H-TOCN, F-TOCN) and sheet form (S-TOCN) was examined for gold adsorptivity from chloride solution. Additionally, this work describes the optimum conditions and parameters for gold recovery. The data obtained in this investigation are also modeled using kinetic (pseudo first-order and pseudo second-order), isotherm best fit (Freundlich, Langmuir and Langmuir-Freundlich), and thermodynamic (endothermic process) parameters. Results demonstrate that high levels of gold removal can be achieved with TEMPO-oxidized cellulose nanofibers (98% by H-TOCNF) and the interaction characteristics of H-TOCN with gold suggests that other precious metals could also be efficiently recovered.

scholarly journals Full Factorial Design for Gold Recovery from Industrial Solutions

Toxics ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 111
Author(s):  
Maria Mihăilescu ◽  
Adina Negrea ◽  
Mihaela Ciopec ◽  
Petru Negrea ◽  
Narcis Duțeanu ◽  
...  
Keyword(s):  
Factorial Design ◽  
Adsorption Capacity ◽  
Contact Time ◽  
Adsorption Process ◽  
Design Method ◽  
Precious Metals ◽  
Gold Recovery ◽  
Maximum Adsorption Capacity ◽  
Gold Concentration ◽  
Commercial Resin

Gold is one of the precious metals with multiple uses, whose deposits are much smaller than the global production needs. Therefore, extracting maximum gold quantities from industrial diluted solutions is a must. Am-L-GA is a new material, obtained by an Amberlite XAD7-type commercial resin, functionalized through saturation with L-glutamic acid, whose adsorption capacity has been proved to be higher than those of other materials utilized for gold adsorption. In this context, this article presents the results of a factorial design experiment for optimizing the gold recovery from residual solutions resulting from the electronics industry using Am-L-GA. Firstly, the material was characterized using atomic force microscopy (AFM), to emphasize the material’s characteristics, essential for the adsorption quality. Then, the study showed that among the parameters taken into account in the analysis (pH, temperature, initial gold concentration, and contact time), the initial gold concentration in the solution plays a determinant role in the removal process and the contact time has a slightly positive effect, whereas the pH and temperature do not influence the adsorption capacity. The maximum adsorption capacity of 29.27 mg/L was obtained by optimizing the adsorption process, with the control factors having the following values: contact time ~106 min, initial Au(III) concentration of ~164 mg/L, pH = 4, and temperature of 25 °C. It is highlighted that the factorial design method is an excellent instrument to determine the effects of different factors influencing the adsorption process. The method can be applied for any adsorption process if it is necessary to reduce the number of experiments, to diminish the resources or time consumption, or for expanding the investigation domain above the experimental limits.

Non-oxidized cellulose nanofibers as a topical hemostat: in vitro thromboelastometry studies of structure vs function

2021 ◽  
pp. 118043
Author(s):  
Elmira Mohamed ◽  
Lucy A. Coupland ◽  
Philip J. Crispin ◽  
Ailene Fitzgerald ◽  
David R. Nisbet ◽  
...  
Keyword(s):  
Cellulose Nanofibers ◽  
Oxidized Cellulose

Fiber Orientation Control by Stretching in Cellulose Nanofiber Green Composites

2017 ◽  
Vol 754 ◽  
pp. 135-138
Author(s):  
Hitoshi Takagi ◽  
Antonio Norio Nakagaito ◽  
Yuya Sakaguchi
Keyword(s):  
Fiber Orientation ◽  
Vinyl Alcohol ◽  
Glass Fibers ◽  
Cellulose Nanofibers ◽  
Polymeric Composite ◽  
High Strength ◽  
Sample Surface ◽  
Cellulose Nanofiber ◽  
Poly Vinyl Alcohol ◽  
Nanofiber Alignment

The presence of nanoscale cellulosic fiber; namely cellulose nanofiber, increases year by year because the mechanical and physical properties are believed to be comparable to those of common glass fibers. On the other hand, most of the reported strength data for the cellulose nanofiber-reinforced polymeric composite materials was not as high as expected. In order to obtain high-strength cellulose nanofiber-reinforced polymer composites, we tried to optimize the fiber orientation of cellulose nanofibers in poly (vinyl alcohol)-based polymer matrix by using a repeated mechanical stretching treatment. The fiber orientation of cellulose nanofibers in the poly (vinyl alcohol) matrix can be modified by changing the total amount of stretching strain applied during the multiple stretching treatments. The degree of fiber alignment was directly evaluated by observing the cellulose nanofibers on the sample surface with a digital microscope. The efficacy of proposed nanofiber alignment control has been explored experimentally and theoretically. The tensile strength and modulus of the cellulosic nanocomposites after applying the multiple stretching treatments increased by approximately 80% and 40% respectively, as compared with those of the untreated nanocomposites.

Investigation of efficiency of a novel, zinc oxide loaded TEMPO-oxidized cellulose nanofiber based hemostat for topical bleeding

2019 ◽  
Vol 126 ◽  
pp. 786-795 ◽  
Author(s):  
Anha Afrin Shefa ◽  
Mirana Taz ◽  
Monir Hossain ◽  
Yong Sik Kim ◽  
Sun Young Lee ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Cellulose Nanofiber ◽  
Oxidized Cellulose

Development of green nanocomposites reinforced by cellulose nanofibers extracted from paper sludge

2015 ◽  
Vol 29 (06n07) ◽  
pp. 1540025 ◽  
Author(s):  
Hitoshi Takagi ◽  
Antonio N. Nakagaito ◽  
Kazuya Kusaka ◽  
Yuya Muneta
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
Mechanical Treatment ◽  
Raw Materials ◽  
Cellulose Nanofibers ◽  
Tensile Tests ◽  
Cellulose Nanofiber ◽  
Paper Sludge ◽  
Reinforcing Effect ◽  
Mechanical And Physical Properties

Cellulose nanofibers have been showing much greater potential to enhance the mechanical and physical properties of polymer-based composite materials. The purpose of this study is to extract the cellulose nanofibers from waste bio-resources; such as waste newspaper and paper sludge. The cellulosic raw materials were treated chemically and physically in order to extract individualized cellulose nanofiber. The combination of acid hydrolysis and following mechanical treatment resulted in the extraction of cellulose nanofibers having diameter of about 40 nm. In order to examine the reinforcing effect of the extracted cellulose nanofibers, fully biodegradable green nanocomposites were fabricated by composing polyvinyl alcohol (PVA) resin with the extracted cellulose nanofibers, and then the tensile tests were conducted. The results showed that the enhancement in mechanical properties was successfully obtained in the cellulose nanofiber/PVA green nanocomposites.

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