Thermosensitive and Wound-Healing Gelatin-Alginate Biopolymer Hydrogels Modified with Humic Acids

The main goal of the article is the creation and study of thermosensitive and wound-healing gelatin-alginate bio-polymer hydrogels modified with humic acids.Their rheological properties,swelling and contraction behavior were experimentally investigated,elucidated using Fourier transform infrared spectroscopy and used to achieve the physiological melting point,which is necessary for successful drug delivery.It has been shown that in the gelatin-alginate-humic acid biopolymer hydrogels systems,it is possible to obtain a gel-sol transition temperature close to the physiological temperature of 37°C,which is important for drug delivery in the treatment of wounds.By changing the type and concentration of humic acids in the gelatin-alginate hydrogel,it turned out to be achiev-able to regulate the softening time of the gel on the human body in the range from 6 to 20 min,which provides the possibility of controlled prolonged delivery of drugs.Based on the study of the influence of calcium ions on the properties of humic acids and ion exchange,as well as the interaction of humic acids,sodium alginate and gelatin with the formation of tighter gel networks,approaches to regulate the rate of softening of hydrogels at physiological temperature and their swelling,which simulates the absorption of exudate,were proposed and implemented.In addition,low shrinkage of the hydrogel surface due to cross-linking of gelatin-alginate networks when modified with humic acids was experimentally confirmed,which is important for avoiding problems of wound contracture and contour deformations when using dressings for wound healing.Thus,the developed opti-mized innovative biopolymer hydrogels synergistically combine the outstanding properties of natural molecular polymers and humic acids and are promising for the creation of effective medicines for wound healing.

Characterization of humic acids extracted from the sediments of the various rivers and lakes in China

The humic acids (HAs) isolated from the sediments of the various rivers,lakes,and reservoirs in China were studied using elemental analyzer,fourier transform infrared (FT-IR),and CP/MAS 13C nuclear magnetic resonance (NMR) spectroscopy.The results showed that the HAs were characterized by some common chemical and physicochemical properties,but they also pose some differences in the C-containing functional groups.The C/N,C/H,O/C,and O/H ratios differ widely for the various HAs,showing that the elemental comp...

Study on the action and mechanism of humic acids in Kaschin-Beck disease

Humic acids, especially FA in fractions, contain more oxygen functional groups. In this experiment, on the basis of confirming the action of humic acids on KBD, what was studied is the biological effects of one of main oxygen functional groups, hydroxy group (-OH). The results indicate that inducing pathologic process of KBD, obviously decrease the GSH-Px activity and induce peroxidation membrane injury of tissue. The SOD activity increase in the tissues caused by oxygen functional groups showed that enhancing of free radical reaction should not be neglected.

Impact of humic acids on the colonic microbiome in healthy volunteers

AIMTo test the effects of humic acids on innate microbial communities of the colon.METHODSWe followed the effects of oral supplementation with humic acids (Activomin®) on concentrations and composition of colonic microbiome in 14 healthy volunteers for 45 d. 3 × 800 mg Activomin® were taken orally for 10 d followed by 3 × 400 mg for 35 d. Colonic microbiota were investigated using multicolor fluorescence in situ hybridization (FISH) of Carnoy fixated and paraffin embedded stool cylinders. Two stool samples were collected a week prior to therapy and one stool sample on days 10, 31 and 45. Forty-one FISH probes representing different bacterial groups were used.RESULTSThe sum concentration of colonic microbiota increased from 20% at day 10 to 30% by day 31 and remained stable until day 45 (32%) of humic acid supplementation (P < 0.001). The increase in the concentrations in each person was due to growth of preexisting groups. The individual microbial profile of the patients remained unchanged. Similarly, the bacterial diversity remained stable. Concentrations of 24 of the 35 substantial groups increased from 20% to 96%. Two bacterial groups detected with Bac303 (Bacteroides) and Myc657 (mycolic acid-containing Actinomycetes) FISH probes decreased (P > 0.05). The others remained unaffected. Bacterial groups with initially marginal concentrations (< 0.1 × 109/mL) demonstrated no response to humic acids. The concentrations of pioneer groups of Bifidobacteriaceae, Enterobacteriaceae and Clostridium difficile increased but the observed differences were statistically not significant.CONCLUSIONHumic acids have a profound effect on healthy colonic microbiome and may be potentially interesting substances for the development of drugs that control the innate colonic microbiome.

Study on Extraction of Biological Humic Acids from Fermented Furfural Residue

[Objective] This study was conducted to obtain the optimal process for the preparation of biological humic acids （BHAs） from fermented furfural residue by al- kali-dissolution and acidification. [Method] BHAs were extracted from fermented furfural residue by the alkali-dissolution and acidification method, to investigate the effects of solid-liquid ratio （mass ratio of fermented furfural residue to water）, alkali concentration, extraction temperature and extraction time on the extraction rate of BHAs by an orthogonal experiment, and then a solid BHA product was obtained by acidification of its extract followed by solid-liquid separation and oven-drying. [Result] The results showed that the optimal extracting conditions were as follows： solid-liquid ratio of 1：8, alkali concentration of 8% KOH, with extracting temperature at 70℃ and extracting time of 2.5 h in the alkali-dissolution step, and in the acidification step, the pH of the BHA mixture was 2.5. Under the optimal conditions, the content of solid BHAs was 76%, and the extraction rate of BHAs was 49%. [Conclusion] This study provides a theoretical basis for the separation and purification of BHAs from fermented furfural residue by the alkali dissolution and acidification method.

Potentiality of Vermicompost Humic Acids in Banana in Vitro Micropropagation Clone： Enano Guantanamero

The research was done at Havana Biofabric, Mayabeque Province. The vitro plants of banana （Musa sp） used came from the clone Enano Guantanamero （viand type）. They come from multiplication phase in a Murashige and MS （Skoog medium）. The objective of this work was to study the potentialities of HA （humic acids） for stimulation of rooting and cell division process, searching for completely synthetic hormone substitution due to its high cost. The multiplication medium contained thiamine （2 mg·L^-1）, myo-inositol （100 mg·L^-1）, sugar （30mg·L^-1）. By the use of HA, five treatments were used with total substitution of auxin and cytokinin （TI： HA （10 mg.Ll）; （T2： HA （20 mg·L^-1）; （T3： HA （30mg·L^-1）; （T4： HA （40 mg·L^-1）; （T5： HA （50 mg·L^-1） and the control with 6BAP （benzil amino purine） （4 mg·L^-1） ＋ IBA （indol butyric acid） （0.65 mg·L^-1）, pH of the medium was adjust just before agar were add. The results showed that in the explants under HA treatments, elongation and cell multiplication were favored confirmed by explants great high, root number and length due to dry mass. The total protein content, reduced carbohydrate and peroxidases enzymatic activity were determine. The use of Vermicompost HA in the in vitro micropropagation of banana allow the elimination of rooting phase saving materials and be able to pass explants directly to Acclimatization phase.

Experimental Study on the Method of Extracting Humic Acids from Brown Coal Using Hydrogen Peroxide

[ Objective l The study aimed to discuss the optimal conditions of extracting humic acids from brown coal using hydrogen peroxide （H202）. [ Method] Fulvic acid （FA） was prepared through oxidizing the brown coal from Qujing City, Yunnan Province using H202, and humic acids were extracted from the original brown coal and its residues respectively, then the dominate constituents of humic acids were obtained by using pH grading method, finally their chemical composition of humid acids was characterized by Fourier transform infrared spectrometry and func- tional group content analysis. [Result] The mass ratio of the brown coal and oxidant affected the yield of FA most obviously, followed by oxidization temperature and duration, while oxidant concentration had no obvious effect. The optimum conditions were determined as follows： coal-oxidant ratio was 1 ： 0.60, oxidization temperature was 45 ℃, oxidization duration was 210 min, and the concentration of hydrogen peroxide was 20%. Under the conditions, the yield of FA was up to 20.40%. Analysis of component properties indicated that the content of carboxyl and total acidic groups in FA improved obviously under the optimum conditions, and the content of active functional groups in OHA was higher than that of HA, while the domi- nate constituents of OHA needed higher pH during precipitation compared with those of HA. [ Conclusion] The research could provide a new method to prepare good humic acids using brown coal,

Extraction and Characterization of Humic Acids and Humin Fractions from a Black Soil of China

Twenty-three progressive extractions were performed to study individual humic acids (HAs) and humin fractions from a typical black soil (Mollisol) in Heilongjiang Province, China using elemental analysis and spectroscopic techniques. After 23 HA extractions the residue was separated into high and low organic carbon humin fractions. HA yield was the highest for the first extraction and then gradually decreased with further extractions. Organic carbon (OC) of the humin fractions accounted for 58% of total OC …

Adsorption of Cu(Ⅱ) on humic acids derived from different organic materials

The adsorption of Cu（Ⅱ） from aqueous solution onto humic acid （HA） which was isolated from cattle manure （CHA）, peat （PHA）, and leaf litter （LHA） as a function of contact time, pH, ion strength, and initial concentration was studied using the batch method. X-ray absorption spectroscopy （XAS） was used to examine the coordination environment of the Cu（ll） adsorbed by HA at a molecular level. Moreover, the chemical compositions of the isolated HA were characterized by elemental analysis and solid-state 13C nuclear magnetic resonance spectroscopy （NMR）. The kinetic data showed that the adsorption equilibrium can be achieved within 8 h. The adsorption kinetics followed the pseudo-second-order equation. The adsorption isotherms could be well fitted by the Langmuir model, and the maximum adsorption capacities of Cu（ll） on CHA, PHA, and LHA were 229.4,210.4, and 197.7 mg g-1, respectively. The adsorption of Cu（Ⅱ） on HA increased with the increase in pH from 2 to 7, and maintained a high level at pH〉7. The adsorption of Cu（Ⅱ） was also strongly influenced by the low ionic strength of 0.01 to 0.2 mol L-1 NaNO3, but was weakly influenced by high ionic strength of 0.4 to 1 mol L-1 NaNO3. The Cu（Ⅱ） adsorption on HA may be mainly attributed to ion exchange and surface complexation. XAS results revealed that the binding site and oxidation state of Cu adsorbed on HA surface did not change at the initial Cu（Ⅱ） concentrations of 15 to 40 mg L 1. For all the Cu（Ⅱ） adsorption samples, each Cu atom was surrounded by 40/N atoms at a bond distance of 1.95 A in the first coordination shell. The presence of the higher Cu coordination shells proved that Cu（Ⅱ） was adsorbed via an inner-sphere covalent bond onto the HA surface. Among the three HA samples, the adsorption capacity and affinity of CHA for Cu（Ⅱ） was the greatest, followed by that of PHA and LHA. All the three HA samples exhibited similar types of elemental and functional groups, but different contents of elemental and functional groups. CHA contained larger proportions of methoxyl C, phenolic C and carbonyl C, and smaller proportions of alkyl C and carbohydrate C than PHA and LHA. The structural differences of the three HA samples are responsible for their distinct adsorption capacity and affinity toward Cu（Ⅱ）. These results are important to achieve better understanding of the behavior of Cu（Ⅱ） in soil and water bodies in the presence of organic materials.

Kinetics study of aqueous sorption of phenanthrene to humic acids and sediments

The sorption behavior was determined for a model polycyclic aromatic hydrocarbon(PAH), i.e., phenanthrene(PHN), from water to three humic acids(HAs) and three sediments in different reacting time. The chemical compositions of HA samples were measured using cross polarization magic angle spinning carbon 13(CPMAS 13 C NMR along with elemental analysis. The dissolved humic substances dissociating from solid HAs and sediments were characterized by 1 H NMR. The experiments indicated that the sorption modes and mechanisms of natural sorbents for PHN varied significantly between short(<7 d) and long contact time and the reaction time should be taken into consideration in studying the overall sorption process. The sorption capacity( K ′ f) and exponent( n ) might be relative to the properties of dissolved humic materials in initial stage but the solid aromatic organic matter after long time reaction. According to the experiments performed in this investigation and the previous researches, a conceptive sorption model was established.

Effect of Pig Manure Application on Structural Characteristics of Humic Acids in Brown Soil

The effect of application of pig manure (PM) on the structural characteristics of humic acids (HAs) of brown soil was studied in field and incubation experiments. The results showed that the number-average molecular weights (Mn), the ratios of C/ H, C/ N and O/C, the contents of carboxyl and phenolic hydroxyl groups, the content ofaromatic C, the values of E2, E4and λ Exmax of HAs all decreased; whereas, the contents of alkyl C and O-alkyl C, the ratio of carboxyl to phenolic hydroxyl groups, the degree of oxidation stability, the absorption intensity at 285 mμ (UV), and 2920cm-1 of HAs increased after the application of PM. The above results indicated that the molecular structure of HAs tended to be more aliphatic and simpler after the application of PM.

Characteristics of isothermal adsorption and desorption of aluminum ion to/from humic acids

The adsorption and desorption characteristics of Al^3＋ to/from humic acids at different pH, ionic strength, and temperature were studied by the C-25 glucosan-gel chromatography method. The results showed that the maximum adsorption amount （Qmax） and adsorption constant （k） increased, whereas, the absolute value of standard thermodynamic molar free energy change （ΔGm^0） decreased with the increase of pH at constant ionic strength and temperature. With ionic strength increasing from 0 to 0.15 mol/L, Qmax, and k increased and the absolute value of ΔGm^0 decreased at constant pH and temperature. High temperature was unfavorable for the adsorption reaction, as indicated by the dramatic decrease of Qmax and the absolute value of ΔGm^0 with an increase in temperature. The standard thermodynamic molar free energy change （ΔGm^0） and the standard thermodynamic enthalpy change （ΔHm^0） of the adsorption reaction were both negative, suggesting that adsorption reaction was spontaneous and exothermic. The desorption rate of HA-Al^3＋ complex accelerated with the decrease of pH, and a significant linear relationship could be obtained between pH and the desorption rates of Al^3＋ from humic acids. These results demonstrated that the Al^3＋ adsorption reaction was a ＂biphase＂ reaction, and adsorption occurred at both the interior and exterior adsorption sites of humic acids.

Content and Partial Characterization of Unknown N in Humic Acids

INTRODUCTION Nitrogen is a key component of soil organic matter. Only when we have succeeded in characterizing the major part of organic N-containing compounds will we be able to understand fully the transformation reactions in the soil and to use soil-N more efficiently. However, only about 1/ 4——1/ 2 of the total N in humic acid (HA), one of the major constituents of soil organic matter, can be accounted for as amino acids and amino sugars, and most of the remainder has still to be accounted for. It has been

Extraction and Characterization of Biological Humic Acids from Fermented Furfural Residue

Objective] This study aimed to eliminate the negative effects brought about by continuous, long-term accumulation of sodium ions in soil on soil environ-ment. [Method] Biological humic acids （BHAs） were extracted from fermented furfural residue via alkali-dissolution and acidification. The effects of solid-liquid ratio （mass ratio of fermented furfural residue to water）, alkali concentration, extraction tempera-ture and extraction time on the content of BHA were investigated. Also its structure was characterized by FTIR. [Result] The optimal extraction conditions were as fol-lows： solid-liquid ratio of 1：7, KOH concentration of 6%, extraction temperature of 70℃ and extraction time of 1 h. Under the optimal conditions, the content of BHAs extracted was up to 8.5%. The infrared spectrum analysis indicated that BHA had more types of functional groups and lower molecular weight than commercial humic acid although they had similar structures. [Conclusion] The technique has the ad-vantages of simple operation and good stability, and is suitable for extracting BHAs. BHAs have a good prospect in developing new types of humic acid fertilizers.

Characteristics and distributions of humic acids in two soil profiles of the southwest China Karst area

Characteristics and distributions of humic acid(HA) and soil organic matter(SOM) in a yellow soil profile and a limestone soil profile of the southwest China Karst area were systematically investigated to reveal their evolutions in different soils of the study area. The results showed that characteristics and distribution of SOM along the two soil profiles were notably different. Total organic carbon(TOC) contents of soil samples decreased just slightly along the limestone soil profile but sharply along the yellow soil profile. TOCs of the limestone soils were significantly higher than those of the corresponding yellow soils, and C/N ratios of SOMs showed a similar variation trend to that of TOCs, indicating that SOM can be better conserved in the limestone soil than in the yellow soil. The soil humic acids were exhaustively extracted and further fractionated according to their apparent molecular weights using ultrafiltration techniques to explore underlying conservation mechanisms. The result showed that C/N ratios of HAs from different limestone soil layers were relatively stable and that large molecular HA fractions predominated the bulk HA of the top soil, indicating that HA in the limestone profile was protected while bio and chemical degradations were retarded. Combined with organic elements contents and mineral contents of two soils, weconcluded that high calcium contents in limestone soils may play a key role in SOM conservation by forming complexation compounds with HAs or/and enclosing SOMs with hypergene CaCO_3 precipitation.

The effects of soil sand contents on characteristics of humic acids along soil profiles

It is generally accepted that the compositions and properties of soil organic matter （SOM） are influenced by many factors. In order to reveal the effects of soil texture on characteristics and dynamics of SOM and its sub-fraction, humic acid （HA）, along two soil profiles, a yellow soil profile and a purplish soil profile, under the same climate and vegetation conditions were determined. Results indi- cate that the decomposition and humification degrees of SOM and HA of the purplish soils are higher than those of the corresponding yellow soils indicated by A/O-A ratios of HAs, TOCs and HA yields of bulk soil samples, neverthe- less, the development degree of the purplish soil is lower than that of the yellow soil. The variations of E4/E6 ratios of HAs along the soil profiles indicate the overall molecular sizes of HAs decreased downward along the soil profiles. A/O-A ratios of HAs decreased downward along both the soil profiles indicate that humification processes decrease downward along both the soil profiles. Leaching of SOM shows significant effects on the distribution and character- istics of HAs in the yellow soil profile but the purplish soil profile, which is consistent with the higher hydrophobicity of HAs in purplish soils, shows that the distribution char- acteristics of SOM along the soil profiles are a complex result of the combination of soil texture and characteristics of SOM itself. The remarkably different sand contents are concluded tentatively as one of reasons to the differentdistributions and dynamics of HAs along the soil profiles, however, to profoundly understand the evolution and transport of SOM along soil profiles needs more researches.

Study on Humic Acids of the Soil Applied with Corn Stalk by Spectroscopy Measurements

Spectroscopy measurements （Fourier transform infrared differential spectroscopy, Carbon-13 nuclear magnetic resonance spectrometry, Matrix-assisted laser resorption/ionization-time of flight mass spectrometry） were performed to study the humic acids of the soil applied with corn stalk. The results showed that after incorporation of corn stalks into the soil, the soil humic acid （HA） changed significantly in different stages. During first 60 days, new HAs were formed by polymerization and seems to be similar to that of initial HAs from composting corn stalk, some little molecular organic matters also reacted with soil HAs and turned into parts of soil HAs. After 60 days of the corn stalk residue incorporation, new HAs were formed by polymerization of decomposed lignin molecules, some methylenes transformed into methyls and methoxyls since the 90th day. Application of corn stalk led to the increase of aliphatic components in soil HAs, the decrease in aromatic components of soil HAs and the suppression in oxidation degree of soil HAs. The average molecular weight of soil HAs also declined because of application of corn stalk.

Sorption of Pb（ll） Ions by Kaolinite Modified with Humic Acids

Sorption of Pb（II） onto modified Jordanian kaolinite clay by Fluka Humic Acid （FHA） or humic acid extracted from King Talal Dam sediments （KTD） was studied using batch technique at different time, concentration, temperatures and pH. The kinetic studies showed that the uptake increases with time and reached the equilibrium in less than 2 hours and fitted pseudo second-order model for the two modified humic acid kaolinite clay. The Pb（II） uptake properties on both modified kaolinite clay fit Langmuir, Freundlich and Dubinin-Radushkevich sorption models. The energy of sorption process calculated from Dubinin-Radushkevich showed that the sorption was a physical one. The values of △G°indicated that the sorption process was favorable, while △H0 values indicated an endothermic process. On the other hand, the process has positive △S0 which drives the sorption process. Kaolinite clay modified by （FHA） showed higher uptake for Pb（II） than that modified by KTD.

Spectroscopic characteristics of two typical soil humic acids in China

Humic acid （HA） is known to be a complex organic compound with varying structural and functional characteristics. In this study, three-dimensional excitation emission matrix fluorescence spectroscopy （3DEEM）, ultraviolet-visible （UV-Vis） and Fourier-transform infrared （FT-IR） were applied to study the fluorescence characteristics and structure of two typical soil HAs in China. The effects of concentration of HA, pH and ionic strength on the fluorescence behaviors were investigated. The results indicate that ionic strength over the range from 0 to 0.05mol L^-1 NaNO3 did not affect the 3DEEM of HA. The concentration of HA and pH of the test solution had obvious effects on the 3DEEM. When the concentration of soil HA was lower than 10mg L^-1, HA has only one obvious fluorescence peak. However, there were several fluorescence peaks for HA in high concentration （≥50mg L^-1）, and its Ex/Em maximum wavelength shifted towards longer wavelength with increasing the concentration of HA. The fluorescence intensity of HA enhanced with the increase of pH, and achieved maximum at pH 10. The effect of pH on the fluorescence intensity of black soil HA （BHA） was the severest and a polycondensation of BHA existed with the change of pH. At the same condition, the fluorescence intensity of red soil HA （RHA） was stronger than that of BHA. At the excitation wavelength of 340nm, the maximum emission peak positions of RHA and BHA were 474 and 504nm at pH 6.0, and their fluorescence quantum yields （QY） were 2.1-2.5% and 1.5-1.9%, respectively. Based on the maximum emission peak positions and fluorescence quantum yield, RHA and BHA can be distinguished.

Removal of pharmaceutical in a biogenic/chemical manganese oxide system driven by manganese-oxidizing bacteria with humic acids as sole carbon source

Bioaugmented sand filtration has attracted considerable attention because it can effectively remove contaminants in drinking water without additional chemical reagent addition.In this study,a synthesized chemical manganese dioxide (MnO_(2)) -coated quartz sand(MnQS) and biogenic manganese oxide (BioMnOx) composite system was proposed to simultaneously remove typical pharmaceutical contaminants and Mn_(2)+.We demonstrated a manganese-oxidizing bacterium,Pseudomonas sp.QJX-1,could oxidize Mn_(2)+to generate BioMnOxusing humic acids (HA) as sole carbon source.The coaction of MnQS,QJX-1,and the generated BioMnOxin simultaneously removing caffeine and Mn_(2)+in the presence of HA was evaluated.We found a synergistic effect between them.MnQS and BioMnOxtogether significantly increased the caffeine removal efficiency from 32.8%(MnQS alone) and 21.5%(BioMnOxalone) to 61.2%.Meanwhile,Mn_(2)+leaked from MnQS was rapidly oxidized by QJX-1 to regenerate reactive BioMnOx,which was beneficial for continuous contaminant removal and system stability.Different degradation intermediates of caffeine oxidized by MnQS and BioMnOxwere detected by LC-QTOF-MS analysis,which implied that caffeine was oxidized by a different pathway.Overall,this work promotes the potential application of bioaugmented sand filtration in pharmaceutical removal in the presence of natural organic matter in drinking water.