Adsorption Of Tannic Acid Research Articles

Preparation of biochar based on self-polymerization of tannic acid and ammonia adsorption performance study

Preparation of biochar based on self-polymerization of tannic acid and ammonia adsorption performance study

Batch Adsorption of Tannins from Stevia Leaf Extract using Activated Carbon: An Investigation into Adsorption Isotherms and Adsorption Energy

Stevia leaf extract (Stevia rebaudiana Bertoni) could have been utilized as an alternative natural sweetener because it possessed a sweetness level 300 times that of sucrose sugar. However, stevia leaf extract still contained a bitter taste attributed to the presence of tannins. The method that can be used to reduce tannin content is batch adsorption using activated carbon. This study aimed to investigate the batch adsorption process for the tannin content of stevia leaf extract using activated carbon with variable adsorption times ranging from 5 to 180 minutes, which included the appropriate adsorption isotherm model and adsorption energy. Stevia leaves were extracted through maceration with 70% ethanol. The results of the stevia leaf extract were adsorbed in batches using activated carbon treated with 1M NaOH. The analysis was carried out by testing the tannin content (mg/g TAE) using a UV-Vis spectrophotometer at a wavelength of 735 nm and calculating the adsorption isotherm and adsorption energy. The results showed that the tannin content before adsorption was 0.910 mg/g TAE, and the lowest tannin content was 0.040 mg/g TAE at 100 minutes. The tannin content decreased between 5–90 minutes, remained constant, reached equilibrium at 95–120 minutes, and increased again at 125–180 minutes. The suitable adsorption isotherm model was the Freundlich isotherm with a value of R2 = 0.9998; KF = 25.293 [(mg/g)(L/mg)1/nf], and adsorption energy = -8.03 kJ/mol. The adsorption that occurred was classified as physical adsorption.

Synthesis of Polymer Brushes on Tannic Acid-Coated Copper Particles and Surface Co-Assembly.

The synthesis of polymer brushes on inorganic particles is an effective approach to surface modification. The polymer brushes on the surface endow the substrates with new surface properties. However, the lack of functional groups and the difficulty of surface modification have made it difficult to develop an effective method for the synthesis of polymer brushes on metal surfaces. Herein, a simple and versatile strategy for synthesizing polymer brushes on copper particles is reported. Tannic acid (TA) molecules are adsorbed onto the surfaces of copper particles, forming TA coatings. Quaternized poly(2-(dimethylamino)ethyl methacrylate)-block-polystyrene (qPDMAEMA-b-PS) block copolymer (BCP) chains are grafted on the TA coatings through hydrogen bonding and electrostatic interaction, and PS brushes are grafted on the copper particles. The effects of TA concentration on the adsorption of TA and PS brush synthesis are discussed. The PS brushes are able to form surface nanostructures on the copper particles through co-assembly with PDMAEMA-b-PS BCP chains. The effect of BCP concentration on the surface nanostructures is investigated. It is reasonable to expect that polymer brushes and surface nanostructures can be synthesized on different metal surfaces by using the TA-coating approach reported in this paper.

Tannic acid self-aggregation and adsorption onto a polyethersulfone membrane: An all-atom molecular dynamics study

Atomic scale modeling is crucial for characterizing the interactions responsible for fouling, which is a major limitation in the use of membrane filtration technologies for the recovery of polyphenols. In this work, a methodology to model a porous ultrafiltration polyethersulfone (PES) membrane is presented. Subsequently, various systems containing tannic acid (TA) molecules at different concentrations (9 or 30 g/L) were studied, with two additional systems incorporating a PES membrane, through 100 ns all-atom molecular dynamics simulations. The results show that up to 90% of the TAs are self-aggregated, associated with the formation of intermolecular H-bond and π-stacking interactions. Furthermore, adsorption of 48–67% of the TAs onto PES was observed. TA-PES H-bond and π-stacking interactions are also formed. The number of adsorbed TAs molecules over time and the evolution of the mean size of TA aggregates exhibits similar temporal trends, suggesting a parallel progression in both phenomena. Moreover, the same atoms were involved in both aggregation and adsorption, leading to the conclusion that the two phenomena compete. These results shed light on the fouling mechanism, which appears to occur through the formation of a cake layer combined with adsorptive fouling, and could support the design of new antifouling agents adapted for polyphenol filtration.

Effect of dry-wet alternation on the adsorption of dissolved organic matter by soil minerals

Dry-wet alternation has an essential effect on soil minerals' adsorption of dissolved organic matter. In this study, kaolin, illite, and hematite were subjected to 0, 1, 3, and 6 dry-wet alternation incubation tests, respectively, and the changes in the characterization of the three minerals were explored by using a BET specific surface area analyzer and an X-ray diffractometer. The effects of different dry-wet alternation treatments on the adsorption of tannic acid and glucose as the representatives of dissolved organic matter were investigated by isothermal and kinetic adsorption tests as well as by different model-fitting methods. The effects of different dry-wet alternation treatments on the adsorption of tannic acid and glucose by the three minerals were investigated by isothermal and kinetic adsorption tests and different model fitting methods. The results showed that alternating dry-wet treatment could change the three minerals' specific surface area and average pore diameter to different degrees. Still, the spacing of the crystal layers did not change significantly. The dry-wet alternation did not alter the adsorption process and tannic acid and glucose adsorption mode. Still, it affected the equilibrium adsorption amount to different degrees, which was illite>hematite>kaolin, and the intensity of the effect was mainly affected by the decrease of the specific surface area of the minerals, which was not related to the change of the average pore diameter and the spacing of the crystal layers.

Efficient adsorption of chloroquine phosphate by a novel sodium alginate/tannic acid double-network hydrogel in a wide pH range

In this work, a novel double-network composite hydrogel (SA/TA), composed of sodium alginate (SA) and tannic acid (TA), was designed and fabricated by a successive cross-linking method using Ti(IV) and Ca(II) as crosslinkers. SA/TA exhibited reinforced mechanical strength and anti-swelling properties because of the double-network structure. SA/TA was used as an adsorbent for removal of a popular antiviral drug, chloroquine phosphate (CQ), in water. The adsorption performance of SA/TA was systematically investigated, to study various effects including those of TA mass content, solution pH, adsorption time, and initial CQ concentration. Adsorption was also examined in presence of inorganic and organic coexisting substances commonly found in wastewater, and under different actual water samples. Batch experimental results indicated that SA/TA could maintain higher and more stable CQ uptakes within a wide solution pH range from 3.0 to 10.0, compared to its precursor, SA hydrogel, owing to the addition of TA-Ti(IV) coordination network. The maximum experimental CQ uptake exhibited by the 1:1 (by wt) SA/TA (SA/TA2) was as high as 0.699 mmol/g at the initial pH of 9.0. A high concentration of coexisting NaCl evidently reduced the CQ uptakes of SA/TA2 due to the electrostatic shielding effect, moreover, divalent cations including Ca(II) and Mg(II) also inhibited the adsorption of CQ due to competitive adsorption. However, humic acid had little effect on this adsorption. Considering the apparent adsorption performance, the aforementioned effects of various factors and the spectroscopic characterizations, multi-interactions are suggested for adsorption including chelation, electrostatic interactions, π-π electron donor-acceptor interaction and hydrogen bonding. SA/TA showed a slight loss in adsorption capacity toward CQ and sustained physicochemical structural stability, even after six adsorption–desorption cycles. In addition to CQ, SA/TA could be efficiently used for adsorption of two other antivirus drugs, namely, hydroxychloroquine sulfate and oseltamivir phosphate. This work provides an effective strategy for the design and fabrication of novel adsorbents that can effectively adsorb antiviral drugs over a wide pH range.

Adsorption mechanism of a biodegradable plant polyphenol depressant for selective separation of chalcopyrite from talc

In this paper, the effect of Tannic acid (TA), a green, biodegradable plant polyphenol, as a talc depressant on the separation behavior of talc and chalcopyrite was investigated. The results of micro-flotation studies revealed that at a TA dosage of 20 mg/L at pH 7, talc recovery was barely 10 % whereas chalcopyrite recovery remained above 90 %, indicating that TA can selectively depress talc flotation. The results of the artificial mixed minerals test further confirmed the depressive effect of TA. The adsorption results showed that the adsorption density of TA on talc was greater than that on chalcopyrite surface. Similar conclusions were observed in zeta potential tests. It is noteworthy that the zeta potential of the chalcopyrite treated with TA and butyl xanthate sodium continued to shift negatively in comparison to the zeta potential of chalcopyrite treated with TA alone, suggesting that butyl xanthate sodium can continue to adsorb on the surface of chalcopyrite following TA treatment. Besides, X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy tests concluded that TA adsorbs on talc surface by physical (hydrophobic) interaction. Differences in the crystal structures of chalcopyrite and talc, as well as the large number of phenolic hydroxyl structures contained in TA, are the main driving forces for the selective adsorption of TA on the talc surface. This work provides an insight to the selection of inhibitors for the separation of chalcopyrite and talc, particularly from the perspective of the hydrophobic effect of the talc layered structure.

Effects of Short-Term Acidification on the Adsorption of Dissolved Organic Matter by Soil Minerals and Its Mechanism of Action

In order to investigate the impact of soil acidification on the adsorption of dissolved organic matter by soil minerals and understand its mechanism, this study selected commonly found minerals in soils, namely illite, kaolin, and hematite, as the research objects. Glucose and tannic acid were considered as the representative compounds for studying the adsorption of dissolved organic matter in soils. By analyzing the effects of the three minerals on the adsorption characteristics of glucose and tannic acid after a short-term acidification treatment, this study aimed to explore the underlying mechanism. To achieve this, scanning electron microscopy and a specific surface area analyzer were utilized. The results of this study indicate that the adsorption modes of the minerals studied were unaffected by short-term acidification. Chemisorption, as well as surface and mesopore diffusion, were found to dominate the adsorption process. In terms of adsorption behavior, the minerals exhibited multilayer inhomogeneous adsorption with glucose and kaolin, while tannic acid showed monolayer adsorption with illite and hematite. When exposed to the same acidification conditions, the saturated adsorption of glucose and tannic acid was found to be illite ≥ hematite > kaolin. The kinetic adsorption processes exhibited three stages: fast adsorption, slow adsorption, and adsorption equilibrium. Interestingly, as the intensity of the acidification increased, the saturated adsorption capacity generally followed the trend of S3 (test minerals with pH adjusted to 3 value) > S5 (test minerals with pH adjusted to 5 value) > CK (the control group). The acidification-induced solvation led to an increase in the specific surface area and the number of active adsorption sites on the minerals. Additionally, the protonation reaction triggered a change in the surface charge, which in turn affected the hydrogen bonding, ligand exchange, and charge transfer between the minerals and glucose and tannic acids. These interactions ultimately enhanced the adsorption capacity.

Flotation behavior and mechanism of tannic acid as a depressant on Cu-Mo flotation separation

The similar flotation performance of chalcopyrite and molybdenite in the bulk concentrate made their separation a challenge. Therefore, selective depression of them was required. Previous studies had tended to focus on chalcopyrite depression. Tannic acid (TA), a macromolecular organic compound, has been used as a molybdenite depressant to separate chalcopyrite from molybdenite in flotation. Micro-flotation experiments showed that the TA demonstrated a stronger depression for molybdenite. The Cu and Mo recovery of 95.01% and 3.34% was achieved with the TA in mixed mineral flotation, respectively. The UV spectroscopy measurements suggested that TA had a greater adsorption amount on the molybdenite surface. XPS analysis showed that there was chemisorption between iron ions on chalcopyrite and TA and non-chemisorption between molybdenite and TA. The molecular dynamics simulation indicated that the hydrophobic interaction caused TA to be adsorbed on the molybdenite surface. The hydrophobic interaction between TA and the molybdenite surface was more favorable for adsorption than the chemical interaction of TA with the chalcopyrite surface. Additionally, it was confirmed by infrared spectroscopy analysis that TA adsorbed on the chalcopyrite surface would prevent the subsequent adsorption of PBX (potassium n-butyl xanthate), while PBX significantly weakens the adsorption of TA on the chalcopyrite surface.

Targeted Removal of Galloylated Flavanols to Adjust Wine Astringency by Using Molecular Imprinting Technology.

Excessive galloylated flavanols not only cause instability in the wine but also lead to unbalanced astringency. Although clarification agents are always used to precipitate unstable tannins in wine, the non-specific adsorption of tannins results in the failure to precisely regulate the tannin composition of the wine. In this work, molecularly imprinted polymers (MIPs) with template molecules of galloylated flavanols were designed to specifically adsorb gallotannins to reduce wine astringency. The results showed that the "pores" on the surface of the MIPs are the structural basis for the specific adsorption of the target substances, and the adsorption process is a chemically driven single-molecule layer adsorption. Moreover, in the mono/oligomeric gallotannin-rich model solution, the adsorption of gallotannins by I-MIPs prepared as single template molecules reached 71.0%, and the adsorption capacity of MIPs for monomeric gallotannins was about 6.0 times higher than polymeric gallotannins. Given the lack of technology for the targeted adsorption of tannins from wine, this work explored the targeted modulation of wine astringency by using molecular imprinting techniques.

Tannic acid purification from pomegranate peel via tannic acid imprinted particle-embedded cryogel column

Tannic acid (TA) is hydrolysable tannin found in the leaves and bark of many herbaceous and woody plants. Purification of TA is important due to its antibacterial, antihistaminic, antioxidant, antimutagenic and antitussive properties. In this study, 2-hydroxyethyl methacrylate-based TA-imprinted particle embedded cryogel (TA-MIP) was synthesized to purify TA from pomegranate peel. Furthermore, non-imprinted particle embedded cryogel (NIP) was synthesized to determine specific adsorption properties of TA-MIP, and control cryogel was synthesized without embedding procedure. The synthesized cryogel columns were characterized via scanning electron microscopy, Brunauer-Emmett-Teller surface area analysis, fourier-transform infrared spectroscopy, and swelling studies. Particle-embedding procedure resulted in a significantly higher specific surface area of particle-embedded columns (TA-MIP and NIP, 29 m2/g and 25 m2/g, respectively) than the specific surface area of control cryogel (9 m2/g). Adsorption studies were performed from aqueous solutions and maximum TA adsorption was found to be 34.4 mg/g for TA-MIP, 3.9 mg/g for NIP, and 2.8 mg/g for control cryogel. Within the scope of selectivity study, it was demonstrated that the synthesized columns have a high selectivity for TA against gallic acid (GA) and quercetin (QCT). Finally, purification of TA directly from pomegranate peel extract was studied and results were confirmed by HPLC. Furthermore, it has been proven that TA-MIP cryogel columns can be repeatedly used up to ten-times without any remarkable reduction in the TA adsorption amount.

Utilization and Mechanisms of Tannic Acid as a Depressant for Chalcopyrite and Pyrite Separation.

Current flotation practices using lime or cyanide as depressants in chalcopyrite and pyrite separation have significant disadvantages, such as substantial reagent consumption, high slurry pH, and environmental hazards. This work aimed to explore the utilization and mechanisms of tannic acid (TA) as an eco-friendly alternative to lime or cyanide in chalcopyrite-pyrite separation. Flotation results showed that TA selectively depressed pyrite yet allowed chalcopyrite to float at neutral or alkaline pH. Adsorption density and zeta potential results indicated that TA adsorbed intensely on pyrite but minorly on chalcopyrite. Besides, potassium ethyl xanthate was still largely adsorbed on chalcopyrite but not on pyrite after TA adsorption. Surface analysis by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy further showed that the oxidation species of FeOOH and Fe2 (SO4)3, particularly FeOOH were the main active sites for TA chemical adsorption. Owing to the greater and faster oxidation of pyrite, more FeOOH and Fe2 (SO4)3 were generated on the pyrite surface, and the chemical adsorption of TA was more pronounced on the pyrite surface than on the chalcopyrite surface.

Adsorption of tannic acid as depressant in the flotation separation of fluorite and bastnaesite

ABSTRACT Fluorite, a strategic industrial mineral, was investigated for flotation separation from bastnaesite with tannic acid (TA) as depressant. In this study, the adsorption analysis indicates that the adsorption density of TA on bastnaesite was greater than that of fluorite. The zeta potential, Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) provide the evidence that chemisorption and electrostatic attraction occurred simultaneously between TA and fluorite or bastnaesite at optimal pH, the latter also involving hydrogen bonding interactions. Furthermore, the micro-flotation and batch flotation results suggest that TA could effectively depress bastnaesite with a negligible effect on fluorite at low concentrations, and that TA attached to the surface of bastnaesite precluded the adsorption of phthalic acid (PA) as collector, whereas it could be adsorbed on the fluorite surface. These findings offer a robust theoretical foundation and valid guidance for the flotation separation of fluorite from bastnaesite in industrial processes.

Effect of chitosan addition on acetaldehyde and polymeric pigments production after oxidation of red wines with different tannin/anthocyanins ratio

In order to evaluate the effect of the application of chitosan to red wines with different initial composition, four wines showing tannins/anthocyanins ratio (T/A) ranging from 0.15 to 2.44 were treated with this amino polysaccharide. As one of the main factors involved in red wine ageing is the oxidation, even a forced oxidation test was applied on all the samples. The addition of chitosan determined a decrease in total phenolic compounds mainly due to the adsorption of protein-reactive tannins which decreased from 10 to 50% of the initial value. The previous addition of chitosan determined a lower production of acetaldehyde after oxidation confirming the antioxidant activity of this amino polysaccharide. The production of acetaldehyde was lower in samples with a higher T/A ratio probably due to the involvement of acetaldehyde in reactions with flavanols and anthocyanins giving polymeric pigments. These results suggest a possible use of chitosan in red wine with a higher T/A ratio to decrease the content of tannins reactive towards proteins and, contemporary, to act as antioxidant.

Modulation of surface properties of cellulose nanocrystals through adsorption of tannic acid and alkyl cellulose derivatives

Cellulose nanocrystals (CNCs) are hydrophilic nanoparticles that cannot be dispersed in non-polar solvents or hydrophobic polymer matrices. Here, we demonstrate the tunable modification of CNC surfaces by physical adsorption of tannic acid (TA) and two alkyl cellulose derivatives (ACDs), methyl cellulose (MC) and ethyl cellulose (EC), while maintaining their sustainable nature. We compare the impact of ACD adsorption when mixed with CNCs to CNCs precoated with tannic acid (CNC@TA), varying ACD weight fractions in CNC suspensions. Our results show that CNC@ACD and CNC@TA@ACD aqueous suspensions display good colloidal stability in water, while their surface properties are altered. We use a wide range of analytical techniques to characterize these suspensions, with a focus on their interaction with water. The two selected ACDs adsorb on both CNCs and CNC@TA at low fractions (ACD ≤ 10 % w/w), followed by an intermediate region of saturation between 10 % and 30 % w/w. At fractions above 30 % w/w, we observe the formation of CNC- or CNC@TA-reinforced ACD composites. Most samples can be redispersed in water upon freeze-drying, except for EC-rich samples redispersible in toluene. Our facile method for preparing ACD-coated CNCs allows for the creation of a range of nanomaterials with modulable wetting and emulsification properties.

Crystal engineering of quercetin via combined adsorption of polyvinylpyrrolidone and tannin

Crystal engineering of quercetin via combined adsorption of polyvinylpyrrolidone and tannin

Adsorption of Tannic Acid onto Gold Surfaces

Thin film coatings are widely applicable in materials for consumer products, electronics, optical coatings, and even biomedical applications. Wet coating can be an effective method to obtain thin films of functional materials, and this technique has recently been studied in depth for the formation of bioinspired polyphenolic films. Naturally occurring polyphenols such as tannic acid (TA) have garnered interest due to their roles in biological processes and their applicability as antioxidants, antibacterial agents, and corrosion inhibitors. Understanding the adsorption of polyphenols to surfaces is a core aspect in the fabrication processes of thin films of these materials. In this work, the adsorption of TA to gold surfaces is measured using a quartz crystal microbalance with dissipation monitoring (QCMD) and surface plasmon resonance (SPR) for a wide range of TA concentrations. The adsorption kinetics, aggregation, and stability of TA solutions in physiological-like conditions are studied. Unexpectedly, it is found that the adsorption rates depend only weakly on concentration because of the presence of TA aggregates that do not adsorb. The mechanism of layer formation is also investigated, finding that TA monolayers readily adsorb onto gold with flat or edge-on molecular orientations dependent on the solution concentration. A mix of orientations in the intermediate case leads to slow multilayer adsorption.

Efficient Removal of Tannic Acid from Olive Mill Wastewater Using Carbon Steel Slag

Mediterranean countries experience a large production of olive oil, thus generating huge quantities of non-biodegradable vegetation waters. The discharge of these effluents into aquatic environments seriously affects the quality of surface waters. This study investigated the potential use of carbon steel slag (SS) as an adsorbent and improver for reducing olive mill wastewater (OMWW) toxicity. The elemental and structural characterization of SS was carried out using inductively coupled plasma-optical emission spectrometry (ICP/EOS), X-ray fluorescence (XRF), X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and Brunauer–Emmett–Teller (BET) analysis. OMWW characterization indicated that the effluent was acidic in nature, with a pH of 4.8, a higher conductivity reaching 14.92 mS/cm, higher COD of 157.31 g/L, rich in organic matter 112.33 g/L, and total phenolic compounds of 11.13 g/L. The neutralization capacity of SS was demonstrated by reducing the OMWW’s acidic character. Afterward, the adsorption of tannic acid (TA) was investigated using SS. Parameters such as contact time, initial TA concentration, adsorbent dosage, pH, and temperature were investigated. The kinetic study indicated that the adsorption of TA onto SS fitted well with the second pseudo-order (r = 0.99) and Elovich (r = 0.98) models, indicating that the adsorption of TA was mainly chemical and depends on the reactions of oxide hydrolysis and hydroxides dissolution. Moreover, Langmuir isotherm has greatly described the adsorption of TA on SS (R = 0.997), suggesting that the surface of SS is homogenous, and the adsorption occurs mainly in monolayer. The maximum adsorption capacity reached 714.28 mg/g, indicating the higher capacity of SS to reduce the polyphenolic compounds in OMWW. This study demonstrated that SS residue from the steelmaking industry could present a highly interesting material for OMWW remediation.

Development of a microfluidic-based taste sensor using lipid polymer membrane

This study aims to develop a microfluidic-based taste sensor for detecting time-dependent human taste sensations. Lipid polymer membranes were welded to perforated polycarbonate films with organic solvents to monitor the adsorption and desorption of taste substances to lipid polymer membranes and to physically immobilize lipid polymer membranes to withstand the pressure of a pumped liquid. A polydimethylsiloxane flow channel was bonded chemically to the polycarbonate film with the lipid polymer membrane using 3-aminopropylethoxysilane. A fabricated microfluidic-based taste sensor could measure the membrane potential change with time due to the adsorption and desorption of tannic acid, an astringency substance, onto a lipid polymer membrane. The proposed sensor could be useful as a tool for assessing the time-course changes in human taste.

Effective adsorption of tannic acid by porous dual crosslinked soy protein isolate-alginate hybrid spheres from aqueous solution

Soy protein isolate-alginate hybrid spheres (SPIAHS) were prepared sequentially by using Ca2+ ions and glutaraldehyde as crosslinkers via the dual crosslinking method for tannic acid (TA) adsorption. SPIAHS samples before (SPIAHS-1) and after (SPIAHS-2) glutaraldehyde crosslinking were featured by SEM, FT-IR, XPS, etc. Adsorption performance for TA from aqueous solution by the SPIAHS-2 was explored under various experimental conditions, such as different initial pH, adsorbent dosage, temperature, etc. SPIAHS-2 manifested a maximal adsorption capacity of 1030 mg/g, being greater than most of the previously reported biosorbents. This result could be principally ascribed to the increased specific surface area, robust spheres of lamellar porous network structure, and richness of organic functional groups anchored on the SPIAHS-2 surface after glutaraldehyde crosslinking. Adsorption kinetics and isotherm investigations disclosed that TA adsorption onto SPIAHS-2 can be commendably depicted by the pseudo-second-order kinetic and obeyed single molecule layer adsorption of the Langmuir model. Moreover, the mechanism of TA adsorption was identified by the hydrogen bonding interaction between the oxygen and nitrogen functional groups of SPIAHS-2 and multiple hydroxyl groups of TA. The TA-loaded SPIAHS-2 could be regenerated and used repeatedly with relatively high adsorption capacity, showing great potential in wastewater treatment for TA removal.