Addition Of Tannic Acid Research Articles

The Use of Froth Flotation for Selective Separation of Plastic Wastes from Soil


 
 
 
 
 The Use of Froth Flotation for Selective Separation of Plastic Wastes from Soil
 
 
 
 
 
 
 
 
 
 Kofi Moro and Dorothy A. Dechie
 
 
 
 
 
 Abstract — In recycling of plastics, unless the goal is to form composites or materials having special properties, it is not advisable to mix plastics of different kinds because of the differences in their molecular weights and chain lengths. Hence, there is the need to separate these plastics when they are mixed before recycle can be done. This project investigated the selective separation of Polypropylene (PP), Polystyrene (PS) and Polyethylene terephthalate (PET) plastics out of soils using froth flotation. Pulverized samples were prepared from post-consumer plastic sources (PP, PS and PET) and soil and mixed uniformly to form a composite sample. The composite sample was subjected to froth flotation. Two tests were performed. A first test, where there was no addition of a depressant (tannic acid), and a second test, where there was addition of tannic acid to depress some of the plastics in order to selectively separate them. Recoveries from each test work indicated that, plastics are naturally hydrophobic and can be floated out of soils without modifying their surface properties. However, selective separations of the plastics were achieved when tannic acid was used to modify the surface properties of the plastic types.

The Physicochemical and Antibacterial Properties of Chitosan-Based Materials Modified with Phenolic Acids Irradiated by UVC Light.

This paper concerns the physicochemical properties of chitosan/phenolic acid thin films irradiated by ultraviolet radiation with wavelengths between 200 and 290 nm (UVC) light. We investigated the preparation and characterization of thin films based on chitosan (CTS) with tannic (TA), caffeic (CA) and ferulic acid (FA) addition as potential food-packaging materials. Such materials were then exposed to the UVC light (254 nm) for 1 and 2 h to perform the sterilization process. Different properties of thin films before and after irradiation were determined by various methods such as Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), atomic force microscopy (AFM), differential scanning calorimeter (DSC), mechanical properties and by the surface free energy determination. Moreover, the antimicrobial activity of the films and their potential to reduce the risk of contamination was assessed. The results showed that the phenolic acid improving properties of chitosan-based films, short UVC radiation may be used as sterilization method for those films, and also that the addition of ferulic acid obtains effective antimicrobial activity, which have great benefit for food packing applications.

A Novel Strategy to Coat Dopamine-Functionalized Titanium Surfaces With Agarose-Based Hydrogels for the Controlled Release of Gentamicin.

IntroductionThe use of spinal implants for the treatment of back disorders is largely affected by the insurgence of infections at the implantation site. Antibacterial coatings have been proposed as a viable solution to limit such infections. However, despite being effective at short-term, conventional coatings lack the ability to prevent infections at medium and long-term. Hydrogel-based drug delivery systems may represent a solution controlling the release of the loaded antibacterial agents while improving cell integration. Agarose, in particular, is a biocompatible natural polysaccharide known to improve cell growth and already used in drug delivery system formulations. In this study, an agarose hydrogel-based coating has been developed for the controlled release of gentamicin (GS).MethodsSand blasted Ti6Al4V discs were grafted with dopamine (DOPA) solution. After, GS loaded agarose hydrogels have been produced and additioned with tannic acid (TA) and calcium chloride (CaCl2) as crosslinkers. The different GS-loaded hydrogel formulations were deposited on Ti6Al4V-DOPA surfaces, and allowed to react under UV irradiation. Surface topography, wettability and composition have been analyzed with profilometry, static contact angle measurement, XPS and FTIR spectroscopy analyses. GS release was performed under pseudo-physiological conditions up to 28 days and the released GS was quantified using a specific ELISA test. The cytotoxicity of the produced coatings against human cells have been tested, along with their antibacterial activity against S. aureus bacteria.ResultsA homogeneous coating was obtained with all the hydrogel formulations. Moreover, the coatings presented a hydrophilic behavior and micro-scale surface roughness. The addition of TA in the hydrogel formulations showed an increase in the release time compared to the normal GS-agarose hydrogels. Moreover, the GS released from these gels was able to significantly inhibit S. aureus growth compared to the GS-agarose hydrogels. The addition of CaCl2 to the gel formulation was able to significantly decrease cytotoxicity of the TA-modified hydrogels.ConclusionsDue to their surface properties, low cytotoxicity and high antibacterial effects, the hereby proposed gentamicin-loaded agarose-hydrogels provide new insight, and represent a promising approach for the surface modification of spinal implants, greatly impacting their application in the orthopedic surgical scenario.

The Physical Adsorption of Gelatinized Starch with Tannic Acid Decreases the Inhibitory Activity of the Polyphenol against α-Amylase.

The effects of mixing orders of tannic acid (TA), starch, and α-amylase on the enzyme inhibition of TA were studied, including mixing TA with α-amylase before starch addition (order 1), mixing TA with pre-gelatinized starch before α-amylase addition (order 2) and co-gelatinizing TA with starch before α-amylase addition (order 3). It was found that the enzyme inhibition was always highest for order 1 because TA could bind with the enzyme active site thoroughly before digestion occurred. Both order 2 and 3 reduced α-amylase inhibition through decreasing binding of TA with the enzyme, which resulted from the non-covalent physical adsorption of TA with gelatinized starch. Interestingly, at low TA concentration, α-amylase inhibition for order 2 was higher than order 3, while at high TA concentration, the inhibition was shown with the opposite trend, which arose from the difference in the adsorption property between the pre-gelatinized and co-gelatinized starch at the corresponding TA concentrations. Moreover, both the crystalline structures and apparent morphology of starch were not significantly altered by TA addition for order 2 and 3. Conclusively, although a polyphenol has an acceptable inhibitory activity in vitro, the actual effect may not reach the expected one when taking processing procedures into account.

Sodium alginate fasten cellulose nanocrystal Ag@AgCl ternary nanocomposites for the synthesis of antibacterial hydrogels

Sodium alginate (SA) hydrogel has broad prospects in medical dressings due to its good biocompatibility and non-toxicity. However, the shortcomings of a single SA hydrogel, such as insufficient toughness and poor antibacterial properties, limit its large-scale application. In this study, SA/CNC–Ag@AgCl/TA (SACT) hydrogels were prepared using CNC–Ag@AgCl and tannic acid (TA) with different contents into SA. The results show that the addition of CNC–Ag@AgCl improves the toughness of the gel, and the addition of TA, and the fracture strain is further improved, and get to 128% form 8% of SA and 78% of SAC. Simultaneously, the antibacterial analysis using the zone-inhibition and colony-counting method shows that the composite hydrogel has decent antibacterial effects on both Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). This work demonstrates a new method for improving the toughness and antibacterial properties of SA hydrogel, which is expected to be used in medical dressings and other relevant fields.

Novel edible coating based on shellac and tannic acid for prolonging postharvest shelf life and improving overall quality of mango

This study aimed to investigate the combined effects of a coating based on shellac and the active agent tannic acid (TA) on the storability and physiological variations of mangoes stored at room temperature. Results showed that TA-shellac prolonged shelf life and improved overall quality of mangoes to a higher extent compared with controls, which was reflected in the extension of shelf life for approximately 10 days, maintaining of tissue firmness and weight loss, slowing down of respiration rate, improvement of physical properties and chemical qualities, suppression of browning, reduction of lipid peroxidation, preservation of aromatic volatiles, and regulation of the related enzymes activities. Addition of TA to shellac coating also improved the antifungal effect of the formulation. The results suggest that a synergistic effect took place between TA and shellac, which demonstrates the high potential for shelf life extension and quality improvement of mangoes of this formulation.

A Novel Method for Stabilizing Zein Gel Particles to Salt Ion-Induced Aggregation.

The destabilization of zein gel particles by salt ions seriously limits their practical application. In this study, zein gel particles exhibiting excellent stability to salt ions were developed by grafting gum arabic with tannic acid. Gum arabic (GA) was first coated onto the surface of zein gel particles, followed by addition of tannic acid to further reinforce non-covalent cross-linking between GA and the zein gel particle surface. The stability of the gel particle dispersions was characterized by Turbiscan analysis, gel particle diameter changes and visual inspection of phase separation. The tannic acid-treated zein–GA gel particles were highly protected from precipitation or aggregation in the presence of NaCl (0–3 mol/L) at different pH values (4.0, 7.0 or 8.5). The gel particles prepared in this study will therefore have broader applicability in different pH and salt ions ion environments.

Morphological changes of ZnO nanostructures upon addition of Tannic Acid

Due to their potential as a good semiconductor, Zinc Oxide nanostructures (ZnO) have received abundant of interest. In this analysis, ZnO nanostructures are synthesized by a hydrothermal process that uses a green method of synthesis completely aided by Tannic Acid (TA). The mean diameter of ZnO nanostructures are observed to increase with addition of TA due to the aggregation that occurred from the influenced of acidic medium. The morphological properties are discussed based on the TEM images which indicated the average size of 8nm for ZnO NPs and 18-23nm for ZnO-TA nanostructures obtained, respectively.

Enhancement of Antibacterial and Mechanical Properties of Photocurable ε-Poly-l-lysine Hydrogels by Tannic Acid Treatment.

In this study, a photocurable hydrogel based on an ε-poly-l-lysine (EPL) composite was fabricated by a grafting reaction using glycidyl methacrylate and then complexed with tannic acid (TA) to improve the mechanical stability and antibacterial performance of the EPL hydrogels. UV-visible spectrophotometry, nuclear magnetic resonance, and Fourier transform infrared spectroscopy were introduced to characterize the chemical construction. The obtained EPLMA hydrogel was immersed into TA solution to induce the forming of the H-bond between EPL and TA, resulting in double networks in the composite hydrogel (EPLMA-TA). Due to the additional hydrogen-bond interaction between TA and EPLMA, the mechanical properties of hydrogels were improved and supported cell growth and proliferation. In addition, the antibacterial properties and antioxidant activities of the EPLMA-TA hydrogels were greatly enhanced due to the addition of TA. All the findings indicate that the EPLMA-TA hydrogels with multiple properties show great potential for biomedicine applications.

Effects of tannic acid on the structure and proteolytic digestion of bovine lactoferrin

Tannic acid (TA) can strongly interact with proteins to improve the stability of protein-based nanoparticles. In the present study, the complexation of TA with bovine lactoferrin (LF) was investigated at pH 6.0. The size and turbidity of the LF-TA complexes did not change significantly until the LF/TA molar ratio was over a critical value of 1:8. Zeta potential of LF-TA was gradually negative as the TA content increased, indicating that there were electrostatic interactions between LF and TA. The circular dichroism (CD) spectroscopy confirmed that TA could further reduce the α-helix and increase the β-sheet content of LF significantly, resulting in a more compact structure of LF. The fluorescence spectra revealed that the interaction between LF and TA caused intramolecular quenching of LF, and the values of Ksv increased with temperature, indicating that static quenching was involved in the interaction between LF and TA. Thermodynamic parameters indicated that the reaction between LF and TA proceed spontaneously, and hydrophobic interactions were the major interaction force. Molecular docking suggested that the binding site of TA and LF was in the inter-leaf region where the two lobes were connected by a spiral. Besides, the proteolytic digestion experiments testified that the addition of TA could reduce the digestibility of LF. Information derived from this work suggests that the addition of TA in LF systems could improve the digestive stability of bio-complex for oral delivery of functional constituents.

Improved photostability of folic acid by the radical-scavenging effect of tannic acid

Folic acid (FA) is sensitive to ultraviolet (UV) light and decomposes into photoproducts with higher fluorescence quantum yield: 6-formylpterin (Fop) and p-aminobenzoylglutamic acid (PABA-Glu). Fop is subsequently oxidized into 6-carboxypterin (Cap). The increased fluorescence intensity of FA solution with increasing irradiation time proved the degradation. Addition of tannic acid (TA) at the TA/FA molar ratio of 0.025/1 could protect 99% FA compared to that no FA could be detected without addition of TA after 120 min of UV irradiation. The retention of FA without TA at pH 5–6 was below 0.4% and above 93% at pH 3–4, but the retention of FA with TA was over 97% for pH 3–6. Moreover, the retention of FA with TA in gummy was over 81% which was significantly higher than that of the one without TA. No covalent bonds were formed between TA and FA. Ethylenediaminetetraacetic acid could not protect FA against photodegradation. Ascorbic acid (Vc) could protect FA to the same extent as TA, but with more addition. It agreed with the results that the DPPH radical-scavenging effect of Vc is lower than TA. These results demonstrated that TA could improve the photostability of FA by the radical-scavenging effect.

PH-Sensitive Dairy-Derived Hydrogels with a Prolonged Drug Release Profile for Cancer Treatment.

A novel versatile biocompatible hydrogel of whey protein isolate (WPI) and two types of tannic acid (TAs) was prepared by crosslinking of WPI with TAs in a one-step method at high temperature for 30 min. WPI is one common protein-based preparation which is used for hydrogel formation. The obtained WPI-TA hydrogels were in disc form and retained their integrity after sterilization by autoclaving. Two TA preparations of differing molecular weight and chemical structure were compared, namely a polygalloyl glucose-rich extract-ALSOK 02-and a polygalloyl quinic acid-rich extract-ALSOK 04. Hydrogel formation was observed for WPI solutions containing both preparations. The swelling characteristics of hydrogels were investigated at room temperature at different pH values, namely 5, 7, and 9. The swelling ability of hydrogels was independent of the chemical structure of the added TAs. A trend of decrease of mass increase (MI) in hydrogels was observed with an increase in the TA/WPI ratio compared to the control WPI hydrogel without TA. This dependence (a MI decrease-TA/WPI ratio) was observed for hydrogels with different types of TA both in neutral and acidic conditions (pH 5.7). Under alkaline conditions (pH 9), negative values of swelling were observed for all hydrogels with a high content of TAs and were accompanied by a significant release of TAs from the hydrogel network. Our studies have shown that the release of TA from hydrogels containing ALSOK04 is higher than from hydrogels containing ALSOK 02. Moreover, the addition of TAs, which display a strong anti-cancer effect, increases the cytotoxicity of WPI-TAs hydrogels against the Hep-2 human laryngeal squamous carcinoma (Hep-2 cells) cell line. Thus, WPI-TA hydrogels with prolonged drug release properties and cytotoxicity effect can be used as anti-cancer scaffolds.

A dual-cross-linked hydrogel based on hyaluronic acid/gelatin tethered via tannic acid: mechanical properties’ enhancement and stability control

Extracellular matrix (ECM) as a network is mainly composed of glycosaminoglycans and proteins. Among these glycosaminoglycans and proteins that naturally occur in ECM, hyaluronic acid (HA) and gelatin attract more attentions. In this work, a chemically cross-linked HA/gelatin hydrogel (HG hydrogel) was firstly fabricated, and then, tannic acid (TA) was introduced as a physical cross-linker, to form a dual-cross-linked network (HG-TAx hydrogels). The strong hydrogen bonding between TA and HG hydrogel resulted in lower swelling ratio, decreasing from 220% (pristine HG hydrogels) to 7.5% (HG-TA25 hydrogels) and stronger mechanical properties increasing from 6 kPa (HG hydrogel) to 160 kPa (HG-TA25 hydrogel). The hydrogel stability in enzyme was significantly improved, attributing to the hyaluronidase inhibition activity of TA. The degradation time significantly increased along with the addition of TA (from 7 up to 21 days). Furthermore, the HG-TAx hydrogels exhibited good cleavage ability to reactive oxygen species (ROS) that could be generated in human tissues, and the antioxidant capacity increased up to 24.2 mg/mL of L-ascorbic acid standard. The improved mechanical properties, prolonged degradation time, and potential antioxidant ability of the HG-TAx hydrogels could pave the way for the design of biomaterials. Furthermore, TA has shown potential biological functions properties and brought the great potential of the HG-TAx hydrogels for implant applications.

Tannic-Acid-Cross-Linked and TiO2-Nanoparticle-Reinforced Chitosan-Based Nanocomposite Film.

A chitosan-based nanocomposite film with tannic acid (TA) as a cross-linker and titanium dioxide nanoparticles (TiO2) as a reinforcing agent was developed with a solution casting technique. TA and TiO2 are biocompatible with chitosan, and this paper studied the synergistic effect of the cross-linker and the reinforcing agent. The addition of TA enhanced the ultraviolet blocking and mechanical properties of the chitosan-based nanocomposite film. The reinforcement of TiO2 in chitosan/TA further improved the nanocomposite film’s mechanical properties compared to the neat chitosan or chitosan/TA film. The thermal stability of the chitosan-based nanocomposite film was slightly enhanced, whereas the swelling ratio decreased. Interestingly, its water vapor barrier property was also significantly increased. The developed chitosan-based nanocomposite film showed potent antioxidant activity, and it is promising for active food packaging.

Comparative effects of addition of monensin, tannic acid and cinnamon essential oil on in vitro gas production parameters of sesame meal

Comparative effects of addition of monensin, tannic acid and cinnamon essential oil on in vitro gas production parameters of sesame meal

Mechanical and antibacterial properties of tannic acid-encapsulated carboxymethyl chitosan/polyvinyl alcohol hydrogels

Abstract The objective of this study was to develop an effective, potential wound dressing, which was constructed with a composite hydrogel of poly(vinyl alcohol) (PVA), carboxymethyl chitosan (CMC) and tannic acid (TA) by cryogenic treatment and freeze-drying method. The as-prepared TA-crosslinked PVA/CMC hydrogels exhibited interconnected pore structure with the mean pore size of roughly 3.7 μm. We found that the compressive strength and stiffness of composite hydrogel increased when the TA component was introduced. However, the PVA/CMC-TA hydrogel possessed obviously lower swell property than that of the TA-free PVA/CMC hydrogel. We also found that the TA addition significantly improved the antibacterial capacity of the as-prepared hydrogel. Moreover, the inhibition zone test showed that the antibacterial activity of PVA/CMC-TA against S. aureus bacteria was greater than that against E. coli. The biological results indicated that the PVA/CMC-TA hydrogel exhibited good cytocompatibility to natural human dermal fibroblasts. In summary, our PVA/CMC-TA composite hydrogel exhibited promising mechanical and antibacterial properties, which showed great potential application as wound healing materials.

Sensing of epigallocatechin gallate and tannic acid based on near infrared optical spectroscopy of DNA-wrapped single-walled carbon nanotube hybrids

The optical responses of DNA-wrapped single-walled carbon nanotubes (DNA-SWNTs) caused by the addition of epigallocatechin gallate (EG) and tannic acid (TA) were investigated. Near infrared absorbance and photoluminescence spectra of pre-oxidized DNA-SWNTs were measured with and without EG and TA. Since both EG and TA have antioxidant abilities, the near infrared spectra changed after the addition of the chemicals. While detection of the antioxidant abilities of EG by DNA-SWNT hybrids has been previously reported, TA was employed for the first time. The changes in the absorbance caused by the addition of TA were found to saturate at 0.33 µM TA, although saturation was not observed even at 3.3 µM with the addition of EG. Oxidation of DNA-SWNT was suppressed by addition of TA or EG. The effects of TA were much greater than those of EG on the absorbance. The photoluminescence did not appear to saturate at 3.3 µM for either EG or TA. photoluminescence had a larger measurement capacity than NIR absorbance. Interestingly, the photoluminescence change caused by EG was much larger than that of TA at 3.3 µM, although the antioxidant property of TA was stronger at 0.33 and 0.033 µM, suggesting that the optical responses were not simple redox reactions. Peak shifts in the absorbance/photoluminescence spectra revealed unique differences according to the chirality of the SWNTs and the types of chemicals used. This suggests that the combination of absorbance/photoluminescence and peak intensity/peak shifts could detect multiple types of chemical information, not only redox reaction. A direct comparison between EG and TA was demonstrated for the first time in this novel study. In addition, sensing of EG and TA by near infrared spectra was made available using not only changes in intensity but also a variety of peak shifts of SWNTs.

Properties of scaffolds based on chitosan and collagen with bioglass 45S5.

Scaffolds based on chitosan (CTS), collagen (Coll) and glycosaminoglycans (GAG) mixtures cross-linked by tannic acid (TA) with bioglass 45S5 addition were obtained with the use of the freeze-drying method. The prepared scaffolds were characterised for morphology, mechanical strength and degradation rate. Moreover, cell viability on the obtained scaffolds was measured with and without the presence of ascorbic acid and dexamethasone. The main purpose of the research was to compare the effectiveness of bioglass 45S5 influence on the physicochemical and biological properties of scaffolds. The results demonstrated that the scaffolds based on the blends of biopolymers cross-linked by TA are stable in an aqueous environment. Scanning electron microscope images allowed the observation of a porous scaffold structure with interconnected pores. The addition of bioglass nanoparticles improved the mechanical properties and decreased the degradation rate of composite materials. The biological properties were improved for 20% tannic acid addition compared to 5%. However, the addition of bioglass 45S5 did not change to cells response significantly.

Novel Eco-Friendly Tannic Acid-Enriched Hydrogels-Preparation and Characterization for Biomedical Application.

Sodium alginate and tannic acid are natural compounds that can be mixed with each other. In this study, we propose novel eco-friendly hydrogels for biomedical applications. Thus, we conducted the following assessments including (i) observation of the structure of hydrogels by scanning electron microscope; (ii) bioerosion and the concentration of released tannic acid from subjected material; (iii) dehydrogenase activity assay to determine antibacterial activity of prepared hydrogels; and (iv) blood and cell compatibility. The results showed that hydrogels based on sodium alginate/tannic acid exert a porous structure. The immersion in simulated body fluid (SBF) results in the biomineralization process occurring on their surface while the bioerosion studies revealed that the addition of tannic acid improves hydrogels’ stability proportional to its concentration. Besides, tannic acid release concentration depends on the type of hydrogels and the highest amount was noticed for those based on sodium alginate with the content of 30% tannic acid. Antibacterial activity of hydrogels was proven for both Gram-negative and Gram-positive bacteria, the hemolysis rate was below 5% and the viability of the cells was elevated with an increasing amount of tannic acid in hydrogels. Collectively, we assume that obtained materials make the imperative to consider them for biomedical applications.

Batik Dye Decolorization by Immobilized Biomass of Aspergillus sp

The rapidity of the batik industry in the Former Residence of Banyumas raises problems. Wastewater that discharged into upstream causes accumulation in downstream up to empties into the sea, so does not only threatens the river ecosystem but also has the potential to cause problems in the mangrove ecosystem in Segara Anakan (the downstream area of the Citanduy River which is very close to the downstream area of the Serayu River Basin). The strategy of batik wastewater management in an effort not to pollute the environment is offered. This study tried indigosol blue batik dye which are often used in the batik industry by using immobilization of the pure fungi biomass compared to biomass which was induced with tannic acid. Combination between incubation time and shaking treatment in immobilization of pure Aspergillus sp. biomass that capable to decolorize indigosol blue batik dye were also done. Data of degradation percentage was analyzed using spectrophotometry. The decolorization result of comparison between biomass of Aspergillus sp. with or without the addition of tannic acid under agitated treatment conditions at 24, 48, 72 hours were 54.7, 75.8, 77.4% and 78.8, 84, 80.1%, respectively. While the result of treatment under static conditions were 65.4, 86.3, 73.7% and 79.2, 78.6, 68.2, respectively. The next experiment is showed that 48th hour on static treatment have the highest decolorization percentage up to 67.1%. The pH was measured before and after treatment. The pH after treatment were decrease both in static and shaking treatment, and also in control treatment both in static and saker treatment. Based on the results of the research, the fact is the use of immobilization biomass of Aspergillus sp. in the form of alginate beads can be used for decolorization application in the environment.