Mechanisms of Cu2+ biosorption on Lessonia nigrescens dead biomass: Functional groups interactions and morphological characterization

2018 ◽  
Vol 6 (2) ◽  
pp. 2696-2704 ◽  
Author(s):  
Héctor A. Cid ◽  
Marcos I. Flores ◽  
Jaime F. Pizarro ◽  
Ximena A. Castillo ◽  
Daniel E. Barros ◽  
...  
2021 ◽  
Vol 11 (9) ◽  
Author(s):  
Asha Singh ◽  
Sunil Kumar ◽  
Vishal Panghal

AbstractThis study evaluated the adsorption of Cr6+ from aqueous solution using dead biomass of aquatic plants Salvinia molesta (Kariba weed) and Typha latifolia (broadleaf cattail). The batch experiments were carried out to study the effects of pH, adsorbent dose, initial metal concentration, contact time, agitation speed in rotation per minute (rpm), and temperature. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were used to characterize the adsorbent and analyze the functional groups and morphology of the adsorbent, respectively. The hydroxyl and amine groups were the main functional groups involved in the adsorption. Both adsorbents showed good results at pH 1, metal concentration of 20 mg/L for Cr6+ removal, and adsorption equilibrium was attained within 60 min with 150 rpm at 25 °C. The adsorption rate obtained was above 95% for both the adsorbents at a dose of 0.150 g for S. molesta and 0.8 g for T. latifolia. Isotherm and kinetic models were applied on the adsorption data. The monolayer adsorption capacity (qm) was found to be 33.33 mg/g for S. molesta and 10.30 mg/g for T. latifolia. The Langmuir isotherm was better fitted to S. molesta, while the Freundlich isotherm was better fitted to T. latifolia. It was reported that the pseudo-second-order model (R2 = 0.999) was better fitted to the adsorption data for both the adsorbents. The thermodynamic study was also conducted and found the adsorption process was exothermic and spontaneous. Results revealed the good adsorption potential of S. molesta and T. latifolia, and they can be used for the removal of hexavalent chromium.


2012 ◽  
Vol 47 (5) ◽  
pp. 687-692 ◽  
Author(s):  
Marcela Guiotoku ◽  
Fabricio Augusto Hansel ◽  
Etelvino Henrique Novotny ◽  
Claudia Maria Branco de Freitas Maia

The objective of this work was to characterize the morphology and molecular composition of the hydrochar produced by microwave-assisted hydrothermal carbonization of cellulose. The produced hydrochar consists mainly of aggregate microspheres with about 2.0 µm in diameter, with aliphatic and aromatic structures and the presence of carbonyl functional groups. The aromatic groups are formed mainly by benzofuran-like structures, being chemically different from common cellulose char. Microwave-assisted hydrothermal carbonization yields a functionalized carbon-rich material similar to that produced by the conventional hydrothermal process.


2016 ◽  
Vol 18 (3) ◽  
pp. 611-620 ◽  

<div> <p>This study compares the distinctive performance, yield and characteristics of bioflocculants (UPMBF13) derived from submerged (SmF) and solid-state fermentation (SSF) of <em>Bacillus subtilis</em> UPMB13. The bioflocculants were subjected to morphological characterization, functional groups determination, molecular weight measurement, protein content quantification and specific compound identification. The SmF and the SSF strategies yielded an average of 2.70 g l<sup>-1</sup> and 1.25 g kg<sup>-1</sup> of UPMBF13, respectively. The submerged UPMBF13 resulted in a clear suspension with visible flocs formation, while flocs from the SSF treatment were less apparent. Higher total proteinaceous contents of UPMBF13 from the SSF led to the inferiority in flocculating performances. The produced UPMBF13 consisted of hydroxyl, carboxyl, methoxyl and carbonyl functional groups which contributed to their flocculating abilities. The molecular weights of UPMBF13 were around 10-50 kDa, characterizing them into low-molecular weight bioflocculants. The submerged UPMBF13 were more fibrous in nature than the SSF, giving the submerged UPMBF13 the upper hand in flocculation. SmF was the best fermentation method yielding high performing bioflocculants at a faster rate by the utilization of non-elaborative techniques. SSF, on the other hand, was proven feasible but further improvements are needed.&nbsp;</p> </div> <p>&nbsp;</p>


Author(s):  
B. L. Soloff ◽  
T. A. Rado

Mycobacteriophage R1 was originally isolated from a lysogenic culture of M. butyricum. The virus was propagated on a leucine-requiring derivative of M. smegmatis, 607 leu−, isolated by nitrosoguanidine mutagenesis of typestrain ATCC 607. Growth was accomplished in a minimal medium containing glycerol and glucose as carbon source and enriched by the addition of 80 μg/ ml L-leucine. Bacteria in early logarithmic growth phase were infected with virus at a multiplicity of 5, and incubated with aeration for 8 hours. The partially lysed suspension was diluted 1:10 in growth medium and incubated for a further 8 hours. This permitted stationary phase cells to re-enter logarithmic growth and resulted in complete lysis of the culture.


Author(s):  
Michael E. Rock ◽  
Vern Kennedy ◽  
Bhaskar Deodhar ◽  
Thomas G. Stoebe

Cellophane is a composite polymer material, made up of regenerated cellulose (usually derived from wood pulp) which has been chemically transformed into "viscose", then formed into a (1 mil thickness) transparent sheet through an extrusion process. Although primarily produced for the food industry, cellophane's use as a separator material in the silver-zinc secondary battery system has proved to be another important market. We examined 14 samples from five producers of cellophane, which are being evaluated as the separator material for a silver/zinc alkaline battery system in an autonomous underwater target vehicle. Our intent was to identify structural and/or chemical differences between samples which could be related to the functional differences seen in the lifetimes of these various battery separators. The unused cellophane samples were examined by transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS). Cellophane samples were cross sectioned (125-150 nm) using a diamond knife on a RMC MT-6000 ultramicrotome. Sections were examined in a Philips 430-T TEM at 200 kV. Analysis included morphological characterization, and EDS (for chemical composition). EDS was performed using an EDAX windowless detector.


1971 ◽  
Author(s):  
Warren G. Bennis ◽  
Michael Beer ◽  
Gerald R. Pieters ◽  
Alan T. Hundert ◽  
Samuel H. Marcus ◽  
...  

Planta Medica ◽  
2010 ◽  
Vol 76 (05) ◽  
Author(s):  
APPR Amarasinghe ◽  
RP Karunagoda ◽  
DSA Wijesundara

2016 ◽  
Vol 19 (2) ◽  
pp. 93-100
Author(s):  
Lalita El Milla

Scaffolds is three dimensional structure that serves as a framework for bone growth. Natural materials are often used in synthesis of bone tissue engineering scaffolds with respect to compliance with the content of the human body. Among the materials used to make scafffold was hydroxyapatite, alginate and chitosan. Hydroxyapatite powder obtained by mixing phosphoric acid and calcium hydroxide, alginate powders extracted from brown algae and chitosan powder acetylated from crab. The purpose of this study was to examine the functional groups of hydroxyapatite, alginate and chitosan. The method used in this study was laboratory experimental using Fourier Transform Infrared (FTIR) spectroscopy for hydroxyapatite, alginate and chitosan powders. The results indicated the presence of functional groups PO43-, O-H and CO32- in hydroxyapatite. In alginate there were O-H, C=O, COOH and C-O-C functional groups, whereas in chitosan there were O-H, N-H, C=O, C-N, and C-O-C. It was concluded that the third material containing functional groups as found in humans that correspond to the scaffolds material in bone tissue engineering.


Sign in / Sign up

Export Citation Format

Share Document