Effect of plasma treatment on chemical composition, structure and sorption properties of lignocellulosic hemp fibers (Cannabis sativa L.)

2020 ◽  
Vol 236 ◽  
pp. 116000 ◽  
Author(s):  
Biljana M. Pejić ◽  
Ana D. Kramar ◽  
Bratislav M. Obradović ◽  
Milorad M. Kuraica ◽  
Andrijana A. Žekić ◽  
...  
2017 ◽  
Vol 82 (12) ◽  
pp. 1417-1431 ◽  
Author(s):  
Marija Vukcevic ◽  
Biljana Pejic ◽  
Ivana Pajic-Lijakovic ◽  
Ana Kalijadis ◽  
Mirjana Kostic ◽  
...  

Waste hemp (Cannabis sativa) fibers were used as sustainable and renewable raw materials for production of low-cost biocarbon sorbent for heavy metals removal. Carbon precursors of different chemical composition were obtained by oxidative and alkaline treatments of hemp fibers. Influence of lignocellulosic precursor chemical composition on hemp fibers-based biocarbon (HFB) characteristics was examined by BET surface area measurement, scanning electron microscopy and mass titration. It was found that lignin content and polymorphic transformation of cellulose increase the SBET of microporous HFBs, while hemicelluloses induce more homogeneous distribution of adsorption active sites. Heavy metal ions adsorption onto HFBs is primarily influenced by the amount of surface oxygen groups, while specific surface area plays a secondary role. Equilibrium data obtained for lead ions adsorption were analyzed by different nonlinear adsorption isotherms, and the best fitting model was chosen using standard deviation and Akaike information criterion (AICC). The maximum adsorption capacities of HFBs ranged from 103.1 to 116.3 mg Pb/g. Thermodynamic parameters showed that Pb2+ adsorption onto HFBs is a spontaneous and complex endothermic process, suggesting the coexistence of physisorption and chemisorption mechanisms.


2018 ◽  
Vol 52 (4) ◽  
pp. 581-586
Author(s):  
P. S. Gordienko ◽  
I. A. Shabalin ◽  
S. B. Yarusova ◽  
Yu. A. Azarova ◽  
S. N. Somova ◽  
...  

Polymer ◽  
2020 ◽  
Vol 190 ◽  
pp. 122191
Author(s):  
Iwona Jakubowska ◽  
Stanisław Popiel ◽  
Mateusz Szala ◽  
Michał Czerwiński ◽  
Maciej Chrunik ◽  
...  

2021 ◽  
pp. 004051752110277
Author(s):  
Qilu Cui ◽  
Jiawei Li ◽  
Chongwen Yu

In this paper, the extraction process of flavonoids from hemp fibers was studied. Response surface methodology (RSM) analysis of the extraction parameters indicated that optimized results would be ethanol concentration 76 vol.%, bath ratio 1:50, and reaction time 139 min; therefore, an optimal extraction rate of flavonoids of 0.2275% can be obtained. The chemical structure, surface morphology and element composition of flavonoid extracts were analyzed. The test results indicated that hemp extract contains flavonoids, which can be used to extract flavonoids from hemp fiber, so as to comprehensively develop hemp fiber and reduce the discharge of waste liquid in the traditional degumming process.


2021 ◽  
Vol 165 ◽  
pp. 113422
Author(s):  
Christoph Kornpointner ◽  
Aitor Sainz Martinez ◽  
Silvija Marinovic ◽  
Christian Haselmair-Gosch ◽  
Polona Jamnik ◽  
...  

Nano Letters ◽  
2003 ◽  
Vol 3 (6) ◽  
pp. 713-718 ◽  
Author(s):  
Aleksey Vishnyakov ◽  
Peter I. Ravikovitch ◽  
Alexander V. Neimark ◽  
Martin Bülow ◽  
Qing Min Wang

2021 ◽  
Vol 316 ◽  
pp. 1019-1024
Author(s):  
O. A. Ignatova ◽  
A. A. Dyatchina

The paper presents the studies’ results of chemical composition, structure, and physico-mechanical properties of high-calcium ashes from the Kansk-Achinsk coals (2017-2019 selection). It was found that ash has a complex poly-mineral composition and contains hydraulically active minerals and oxides of СаОfr, β-C2S, CA, C3A, C4AF, C2F, CaSO4. According to the content of CaOfr, MgO does not meet standards’ requirements. The uniformity of the volume change is maintained by the composition with 50% of cement. The structure and hardening kinetics of ash and ash-cement stone compositions, obtained from the test of normal density, were analyzed. It was established that the hardening of compositions with ash from the Kansk-Achinsk coals was largely influenced by ash minerals. An equivalent amount of cement in composite binders cannot be replaced. In order to obtain a positive effect, compositions with ash instead cement of no more than 30% and a part of fine aggregate, without exceeding the ratio of ash: cement = 1: 1, should be used.


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