scholarly journals Characterization of Interaction Between Humic Acids and Buckminsterfullerene Using Flourescene Spectroscopy

2017 ◽  
pp. 936-947
Author(s):  
Linda Ansone ◽  
Maris Klavins
Keyword(s):  
Wastewater Treatment ◽  
Humic Acids ◽  
Hydrophobic Interactions ◽  
Interaction Model ◽  
Binding Constants ◽  
Kd Values ◽  
Study Support ◽  
Different Origins ◽  
Buckminsterfullerene C60

The interaction between buckminsterfullerene C60 and humic acids (HA) of different origins was compared using fluorescence spectroscopy as a function of pH, humic acid concentration, ionic strength. Binding constants between fullerene and humic acids were calculated. It can be suggested that the complexation was driven by hydrophobic interactions depending on the properties of the interacting compounds. Hydrophobic interaction model as indicated by linear Stern-Volmer plots and high Kd values is characterizing the interaction between buckminsterfullerene C60 and humic acids The results of this study support the development of an understanding of the fate of nanomaterials in the environment as well as the development of analytical methods for nanomaterials in waters and wastewater treatment approaches.

Characterization of interaction between tricyclic structures containing pharmaceuticals, their models and humic substances

2011 ◽  
Vol 63 (5) ◽  
pp. 845-852 ◽  
Author(s):  
M. Klavins ◽  
L. Ansone ◽  
O. Purmalis ◽  
A. Zicmanis
Keyword(s):  
Humic Acids ◽  
Functional Group ◽  
Hydrophobic Interactions ◽  
Binding Constants ◽  
Emerging Pollutants ◽  
Kd Values ◽  
Ring Structures ◽  
Model Substances ◽  
Different Origins

Their persistence and wide consumption identify pharmaceuticals as “emerging pollutants”. The complexation of pharmaceuticals containing adamantine ring structures and their model substances with humic acids (HA) of different origins was compared using fluorescence spectroscopy as a function of pH, humic acid concentration, ionic strength, and molecular mass of HA. Binding constants between the studied pharmaceuticals and humic acids were calculated. A combination of dynamic and static quenching processes as indicated by nonlinear Stern-Volmer plots and high Kd values were positively correlated with the concentration of carboxyl groups in the studied humic acids. For basic functional group-containing pharmaceuticals, the complexation was driven by cation exchange and hydrophobic interactions depending on the properties of the interacting compounds.

scholarly journals Thermodynamic Characterization of Humic Acid-surfactant Interaction: New Insights into the Characteristics and Structure of Humic Acids

2015 ◽  
Vol 39 (6) ◽  
pp. 1633-1642 ◽  
Author(s):  
Leonardus Vergütz ◽  
Luis Henrique Mendes da Silva ◽  
Roberto Ferreira Novais ◽  
Maria do Carmo Hespanhol da Silva ◽  
Aparecida Barbosa Mageste ◽  
...  
Keyword(s):  
Humic Acids ◽  
Cationic Surfactants ◽  
Basic Structure ◽  
Molecular Probes ◽  
Good Choice ◽  
Titration Calorimetry ◽  
Structural Details ◽  
Different Origins ◽  
Different Sources

ABSTRACT Humic acids (HA) are a component of humic substances (HS), which are found in nearly all soils, sediments, and waters. They play a key role in many, if not most, chemical and physical properties in their environment. Despite the importance of HA, their high complexity makes them a poorly understood system. Therefore, understanding the physicochemical properties and interactions of HA is crucial for determining their fundamental role and obtaining structural details. Cationic surfactants are known to interact electrostatically and hydrophobically with HA. Because they are a very well-known and characterized system, they offer a good choice as molecular probes for studying HA. The objective of this study was to evaluate the interaction between cationic surfactants and HA through isothermal titration calorimetry in a thermodynamic manner, aiming to obtain information about the basic structure of HA, the nature of this interaction, and if HA from different origins show different basic structures. Contrary to what the supramolecular model asserts, HA structure is not loosely held, though it may separate depending on the conditions the HA are subjected to in their milieu. It did not show any division or conformational change when interacting with surfactants. The basic structure of the HA remains virtually the same regardless of the different sources and compositions of these HA.

Evaluation of Molecular Markers Specific for 1BL∙1RS Translocation and Characterization of 1RS Chromosome in Wheat Varieties from Different Origins

2009 ◽  
Vol 35 (11) ◽  
pp. 2107-2115 ◽  
Author(s):  
Huai-Jun TANG ◽  
Gui-Hong YIN ◽  
Xian-Chun XIA ◽  
Jian-Jun FENG ◽  
Yan-Ying QU ◽  
...  
Keyword(s):  
Molecular Markers ◽  
Wheat Varieties ◽  
Different Origins

Prediction of the O2 Conditions in the Selector

1994 ◽  
Vol 29 (7) ◽  
pp. 229-237 ◽  
Author(s):  
J. Kruit ◽  
F. Boley ◽  
L. J. A. M. Jacobs ◽  
T. W. M. Wouda
Keyword(s):  
Wastewater Treatment ◽  
Pilot Plant ◽  
Wastewater Treatment Plants ◽  
Coarse Filter ◽  
Plant Research ◽  
Influent Characterization

Influent characterization and biosorption experiments were carried out with settled influent of seven wastewater treatment plants to study the influence of O2 in the selector in relation to the success of developing good settling properties of the sludge. In previous years working selectors were installed and/or pilot plant research was carried out at these wastewater treatment plants. Characterization of the influent was done with help of standard COD and BOD measurements with help of a coarse filter. The research has elucidated that the presence of O2 in the selector, at initial sludge loadings of 3.5-6.5 kg BOD/kg MLSS.d, is important for producing good settling properties of the sludge when the sum of readily biodegradable COD and rapidly hydrolysable COD is greater than 40%. When the sum of sludge COD and slow hydrolysable COD is greater than 50% an unaerated selector can be used.

scholarly journals Characterization of Soil Organic Matter Individual Fractions (Fulvic Acids, Humic Acids, and Humins) by Spectroscopic and Electrochemical Techniques in Agricultural Soils

Agronomy ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1067
Author(s):  
Aleksandra Ukalska-Jaruga ◽  
Romualda Bejger ◽  
Guillaume Debaene ◽  
Bożena Smreczak
Keyword(s):  
Molecular Weight ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
Humic Substances ◽  
Humic Acids ◽  
Agricultural Soils ◽  
Fulvic Acids ◽  
Sorption Properties ◽  
Aliphatic Chains

The objective of this paper was to investigate the molecular characterization of soil organic matter fractions (humic substances (HS): fulvic acids-FAs, humic acids-HAs, and humins-HNs), which are the most reactive soil components. A wide spectrum of spectroscopic (UV–VIS and VIS–nearIR), as well as electrochemical (zeta potential, particle size diameter, and polydispersity index), methods were applied to find the relevant differences in the behavior, formation, composition, and sorption properties of HS fractions derived from various soils. Soil material (n = 30) used for the study were sampled from the surface layer (0–30 cm) of agricultural soils. FAs and HAs were isolated by sequential extraction in alkaline and acidic solutions, according to the International Humic Substances Society method, while HNs was determined in the soil residue (after FAs and HAs extraction) by mineral fraction digestion using a 0.1M HCL/0.3M HF mixture and DMSO. Our study showed that significant differences in the molecular structures of FAs, Has, and HNs occurred. Optical analysis confirmed the lower molecular weight of FAs with high amount of lignin-like compounds and the higher weighted aliphatic–aromatic structure of HAs. The HNs were characterized by a very pronounced and strong condensed structure associated with the highest molecular weight. HAs and HNs molecules exhibited an abundance of acidic, phenolic, and amine functional groups at the aromatic ring and aliphatic chains, while FAs mainly showed the presence of methyl, methylene, ethenyl, and carboxyl reactive groups. HS was characterized by high polydispersity related with their structure. FAs were characterized by ellipsoidal shape as being associated to the long aliphatic chains, while HAs and HNs revealed a smaller particle diameter and a more spherical shape caused by the higher intermolecular forcing between the particles. The observed trends directly indicate that individual HS fractions differ in behavior, formation, composition, and sorption properties, which reflects their binding potential to other molecules depending on soil properties resulting from their type. The determined properties of individual HS fractions are presented as averaged characteristics over the examined soils with different physico-chemical properties.

scholarly journals Characterization of efficient xylanases from industrial-scale pulp and paper wastewater treatment microbiota

AMB Express ◽  
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jia Wang ◽  
Jiawei Liang ◽  
Yonghong Li ◽  
Lingmin Tian ◽  
Yongjun Wei
Keyword(s):  
Wastewater Treatment ◽  
Xylanase Activity ◽  
Pulp And Paper ◽  
Optimal Conditions ◽  
Paper Wastewater ◽  
Termite Hindgut ◽  
Uncultured Microorganisms ◽  
Metagenomic Approach ◽  
Gh10 Family

AbstractXylanases are widely used enzymes in the food, textile, and paper industries. Most efficient xylanases have been identified from lignocellulose-degrading microbiota, such as the microbiota of the cow rumen and the termite hindgut. Xylanase genes from efficient pulp and paper wastewater treatment (PPWT) microbiota have been previously recovered by metagenomics, assigning most of the xylanase genes to the GH10 family. In this study, a total of 40 GH10 family xylanase genes derived from a certain PPWT microbiota were cloned and expressed in Escherichia coli BL21 (DE3). Among these xylanase genes, 14 showed xylanase activity on beechwood substrate. Two of these, PW-xyl9 and PW-xyl37, showed high activities, and were purified to evaluate their xylanase properties. Values of optimal pH and temperature for PW-xyl9 were pH 7 and 60 ℃, respectively, while those for PW-xyl37 were pH 7 and 55 ℃, respectively; their specific xylanase activities under optimal conditions were 470.1 U/mg protein and 113.7 U/mg protein, respectively. Furthermore, the Km values of PW-xyl9 and PW-xyl37 were determined as 8.02 and 18.8 g/L, respectively. The characterization of these two xylanases paves the way for potential application in future pulp and paper production and other industries, indicating that PPWT microbiota has been an undiscovered reservoir of efficient lignocellulase genes. This study demonstrates that a metagenomic approach has the potential to screen efficient xylanases of uncultured microorganisms from lignocellulose-degrading microbiota. In a similar way, other efficient lignocellulase genes might be identified from PPWT treatment microbiota in the future.

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