Adsorption Of Tannic Acid Research Articles

Effects on the purification of tannic acid and natural dissolved organic matter by forward osmosis membrane

The purification performance of tannic acid and dissolved organic matter (DOM) contained real surface water by forward osmosis (FO) was investigated systematically. Since representing the main characteristics of natural DOM fractions, tannic acid was first used as a surrogate for natural DOM analysis. The FO could reject tannic acid effectively with removal efficiencies of approximately 99.0%, as well as for natural DOM removal. The more severe fouling flux decline accompanied with lower tannic acid retention was found at greater draw solution concentrations and in the active-layer-facing-the-draw-solution (AL-facing-DS) orientation, which was ascribed mainly to the more severe fouling resulting from greater tannic acid adsorption in the porous support layer of the FO membrane under these conditions. In the AL-facing-DS mode, it was revealed that the higher the concentrations of initial substances (i.e., tannic acid and calcium ion) in the feed water, the more notable fouling flux decline and tannic acid retention occurred. In natural DOM purification experiments, the main factors investigated had the similar influences on FO performance as those mentioned above. Further, the membrane orientation has a minor impact on the natural DOM removal by FO membrane. The permeation drag influenced by the water flux probably played a critical role in the retention of tannic acid and natural DOM contained surface water by the FO membrane in AL-facing-DS mode.

Modelling and understanding the competitive adsorption of microcystins and tannic acid

A predictive model integrating adsorption kinetics and competitive isotherm models (Homogeneous Surface Diffusion Model, Freundlich-type and Fritz & Schlünder isotherms) was developed to describe and understand the competing mechanism(s) and the ionic strength (IS) role on microcystins (MC) and tannic acid (TA) competitive adsorption. The developed model showed good agreement with the experimental data obtained from batch adsorption tests and isotherms conducted with MC extracts and TA model solutions (single-solute and multicomponent, IS presence and absence) using a mesoporous powdered activated carbon (PAC). Results confirm that similar size molecules such as MC and TA are strong competitors and tannin-rich waters may severely affect MC residuals in the treated water. Unlike usually considered, both direct site and pore blockage mechanisms seem relevant. Competition effects appear to be more dependent on the competitor/contaminant molar ratio than on the initial concentrations. The IS affects the extent and the mechanisms of MC-TA competitive adsorption, reducing PAC dose for safe control of MC residuals. The developed model, including a Ds analysis, is an important tool to understand the competitive adsorption of similar size adsorbates.

Tannic acid adsorption/desorption study onto/from commercial activated carbon

This study reports tannic acid adsorption onto commercial activated carbon (ACC) in a batch system. Adsorption process parameters namely pH, adsorbent dose (mad), temperature (T), initial tannic acid concentration (Co), and contact time (t) were studied and optimized. Optimum pH and adsorbent dose were found to be 3.0 and 15 g/l, respectively. Equilibrium contact time was found to be 7 h. Pseudo-second-order kinetic best fits the adsorption kinetic data. Three isotherms namely Langmuir, Temkin, and Redlich and Peterson (R–P) isotherms were studied and it was found that Langmuir and R–P isotherm generally fitted the experimental equilibrium adsorption data. Endothermic nature of the adsorption of tannic acid onto ACC was concluded, and heat of adsorption was found to be as 89.55 kJ/mol. On considering the cost of ACC, regeneration studies of Tannic acid (TA) loaded ACC have been performed using solvent and thermal desorption methods.

Adsorption and Desorption Behavior of Tannic Acid in Aqueous Solution on Polyaniline Adsorbent

Tannic acid is generally considered as one of polyphenolic pollutants, which may cause severe threats to the environment. In this study, polyaniline adsorbent was synthesized by chemical oxidation to remove tannic acid in aqueous solutions. The adsorption amount of tannic acid varied greatly with pH of solution and strong adsorption was at pH 5.8–6.7. Coexisting cations, such as Na+, K+, and Ca2+, can enhance the adsorption of tannic acid on polyaniline, which may be contributed to the electrostatic interaction between tannic acid and polyaniline. The adsorption process could be well described by Langmuir model and the maximum adsorption capacity was 117.65 mg·g−1 at 35 °C and pH 6.0. The thermodynamic parameters calculated from the adsorption isotherms indicate that the adsorption of tannic acid is spontaneous and endothermic process. The polyaniline saturated with tannic acid can be desorbed in alkaline solution and regenerated adsorbent can be used repeatedly with high adsorption capacity, which implies that polyaniline adsorbents have a great potential in water purification for the removal of tannic acid.

Preliminary extraction of tannins by 1‐butyl‐3‐methylimidazole bromide and its subsequent removal from Galla chinensis extract using macroporous resins

In recent years, ionic liquids have become increasingly attractive as 'green solvents' used in the extraction of bioactive compounds from natural plant. However, the separation of ionic liquid from the target compounds was difficult, due to their low vapour pressure and high stabilities. In our study, ionic liquid-based ultrasonic and microwave-assisted extraction was used to obtain the crude tannins, then the macroporous resin adsorption technology was further employed to purify the tannins and remove the ionic liquid from crude extract. The results showed that XDA-6 had higher separation efficiency than other tested resins, and the equilibrium experimental data were well fitted to Langmuir isotherms. Dynamic adsorption and desorption were performed on XDA-6 packed in glass columns to optimise the separation process. The optimum conditions as follows: the ratio of column height to diameter bed was 1:8, flow rate 1 BV/h (bed volume per hour), 85% ethanol was used as eluant while the elution volume was 2 BV. Under the optimised conditions, the adsorption and desoption rate of tannins in XDA-6 were 94.81 and 91.63%, respectively. The content of tannins was increased from 70.24% in Galla chinensis extract to 85.12% with a recovery of 99.06%. The result of ultra-performance liquid chromatography (UPLC)-MS/MS analysis showed that [bmim]Br could be removed from extract.

Adsorption of Natural Organic Matter Surrogates from Aqueous Solution by Multiwalled Carbon Nanotubes

Adsorption of two natural organic matter (NOM) surrogates (tannic acid and gallic acid) by powdered activated carbon (PAC) and four kinds of multiwalled carbon nanotubes (MWCNTs) with different diameters was investigated in aqueous solution. The tannic acid (TA) adsorption isotherm fit the Langmuir model best, while adsorption of gallic acid (GA) fit the Freundlich model. PAC has a higher adsorption capacity for GA due to the pore-filling effect, while TA adsorption on PAC was lower than that on MWCNTs because of the molecule sieving effect. Adsorption of GA and TA on MWCNTs decreased with increasing MWCNT diameter, but neither surface area nor total pore volume alone can fully explain adsorption of the two NOM surrogates on MWCNTs. Adsorption mechanisms including electrostatic interaction, hydrophobic interaction, hydrogen bond, and π–π interaction play roles in the adsorption process. This study implies that NOM properties have a great effect on their adsorption on MWCNTs, and these properties should be further considered when evaluating the risks of NOM-coated nanomaterials.

매염제 처리가 대나무잎과 솔잎 추출물로 염색한 직물의 물성 및 태에 미치는 영향

This research categorizes fundamental data needed to develop eco-friendly fabrics treated with bamboo leaf & pine leaf extracts. The effect of mordant on those fabrics was analyzed through the measurement of mechanical properties and the estimation of primary hand values for cotton and silk fabrics dyed with bamboo leaf and pine leaf extracts that were later treated with various mordants. When cotton was dyed with bamboo leaves and pine leaves extracts, EM, WT, 2HB, 2HG, 2HG5, LC, T, and W increased however, RT, SMD, and RC decreased compared to raw cotton fabric. The B, G, and MIU increased after mordant treatment to the dyed cotton and resulted in a stiffer and rougher cotton's hand. EM, WT, RT, MIU, WC, T, and W increased (in terms of silk); however, LT, B, 2HB, G, 2HG, 2HG5, MMD, SMD, and LC decreased compared to raw silk fabric. Similar to the dyed cotton, mordant treatment increased the MIU and LC of dyed silk subsequently, the hand became stiffer and rougher. A greater tannin adsorption results in an increased mechanical property and the primary hand value. For both fabrics, mordant treatment made its smoothness drop. However, the scale of drop for cotton was significant, while the scale of the drop for silk was minor. In terms of type of mordant, femordant and natural-mordant treatment influenced the tensile, shear, surface properties of fabrics, and primary hand values more than Cu-mordant and synthetic-mordant in addition, this increased the stiffness, hardness, and roughness of fabrics.

Competitive adsorption of the herbicide fluroxypyr and tannic acid from distilled and tap water on activated carbons and their thermal desorption

A study was conducted on batch and column competitive adsorption of fluroxypyr (FLX) and tannic acid (TA) from distilled (DW) and tap water (TW) on activated carbon cloth (ACC) and granular activated carbon (GAC). Thermal desorption of the adsorbates from the spent ACC was also studied. FLX adsorption was higher from TW than from DW at low FLX equilibrium concentrations, and the inverse was observed at high FLX concentrations. The presence of TA diminished the amount of FLX adsorbed from both solvents due to partial blocking of the microporosity, but the same trends as before were observed at low and high FLX concentrations. Carbon consumption, obtained from the breakthrough curves, was lower as a function of superficial contact time with ACC than with GAC. The presence of TA increased carbon consumption, which was related to the microporosity of the adsorbents. Thermal desorption profiles of the spent ACC showed two peaks and one peak after adsorption from DW and TW, respectively. Desorption peaks shifted to higher temperatures with an increase in the heating rate, allowing the apparent activation energies and pre-exponential factors of the desorption processes to be determined.

Effects of Acid and Heat Treatments on the Structure of Sepiolite and its Adsorption of Tannin

In this paper, it was investigated the changes of structure of sepiolites under different conditions of acid treatments and heat treatments using fourier transform infrared spectroscopy(FTIR). At the same time, through the tannin adsorption experiments, it was studied the changes adsorption properties of sepiolites by acid treatments and heat treatments. The H2SO4 treatment was found to be more effective for the removal of tannin than HCl and HNO3 treatments. With increasing the acid concentration and acid treatment time of H2SO4, the removal rates and adsorption capacity of tannin by sepiolites were first increased and then decreased. The removal rates and adsorption capacity were 61.0% and 23.7mg/g when the acid concentration was 4.0mol/l. And the removal rates and adsorption capacity were 62.5% and 24.3mg/g when the acid treatment time was 16 hours. The calcinations treatment exhibited significant effects on the adsorption of tannin. The removal rates and adsorption capacity were 77.9% and 30.8mg/g when the calcined temperature was 400°C. However, when the calcined temperature was 700°C, the removal rates and adsorption capacity were only 54.1% and 20.8mg/g.

Enzyme-catalyzed modification of PES surfaces: Reduction in adsorption of BSA, dextrin and tannin

Poly(ethersulfone) (PES) can be modified in a flexible manner using mild, environmentally benign components such as 4-hydroxybenzoic acid and gallic acid, which can be attached to the surface via catalysis by the enzyme laccase. This leads to grafting of mostly linear polymeric chains (for 4-hydroxybenzoic acid, and for gallic acid at low concentration and short modification time) and of networks (for gallic acid at high concentration and long exposure time). The reaction is stopped at a specific time, and the modified surfaces are tested for adsorption of BSA, dextrin and tannin using in-situ reflectometry and AFM imaging.At short modification times, the adsorption of BSA, dextrin and tannin is significantly reduced. However, at longer modification times, the adsorption increases again for both substrates. As the contact angle on modified surfaces at short modification times is reduced (indicative of more hydrophilic surfaces), and keeps the same low values at longer modification times, hydrophilicity is not the only determining factor for the measured differences. At longer modification times, intra-layer reactivity will increase the amount of cross-linking (especially for gallic acid), branching (for 4-hydroxybenzoic acid) and/or collapse of the polymer chains. This leads to more compact layers, which leads to increased protein adsorption.The modifications were shown to have clear potential for reduction of fouling by proteins, polysaccharides, and polyphenols, which could be related to the surface morphology.

Adsorption of tannic acid and phenol on mesoporous carbon activated by CO2

Ordered mesoporous carbon CMK-3 was synthesized and further activated using CO2 at 1173K for 2h (C1173-2). Batch experiments were conducted to access the adsorption properties of C1173-2 towards aqueous phenol and tannic acid. Nonporous graphite, the pristine CMK-3, and a commercial microporous activated carbon (AC) were also included as comparative adsorbents. The adsorption affinity of C1173-2 for both phenol and tannic acid was much higher than that of CMK-3, resulting from the enhanced specific surface area of C1173-2. After normalizing for adsorbent surface area, phenol adsorption on the three porous carbons was comparable. However, tannic acid adsorption on C1173-2 was similar to that on CMK-3, but prominently higher than that on AC. N2 adsorption results of the porous adsorbents with tannic acid loaded reflected that the pore volume, especially micropore volume of C1173-2 and CMK-3, was effectively utilized by tannic acid, which was different from the poor occupation of pore volumes for AC. Phenol and tannic acid adsorption over C1173-2, CMK-3 and AC followed the pseudo-second order model and the adsorption rate of C1173-2 was the highest. Moreover, adsorption of the two solutes on C1173-2, CMK-3 and AC was affected by external mass transfer and intraparticle diffusion. To our knowledge, it is the first study on the adsorption of aqueous organic contaminants on mesoporous carbon activated by CO2. The findings highlight the significance of CO2 activation method to improve the adsorption properties of ordered mesoporous carbon for aqueous organic contaminants.

Microwave Regeneration of Field-Spent Granular Activated Carbon from Power Plants

Granular activated carbon (GAC) is extensively used to remove natural organic matter and residential chlorine in water treatment process of power plant. After being used, the spent GAC needs to be regenerated in order to save on operation costs and reduce solid waste disposal. In this study, microwave technique was tried to regenerate the field-spent GAC from a power plant. The effect of microwave power, irradiation time and hydrochloric acid pretreatment were investigated, it was found that microwave could recover the adsorption capacity of GAC within a short time and the tannic acid adsorption efficiency of regenerated GAC was 9 times greater than spent GAC; hydrochloric acid pretreatment could improve the regeneration process, it showed the highest removal efficiency and iodine number, 99.6% and 859 mg/g respectively. The results obtained from SEM-EDX showed that hydrochloric acid pretreatment could remove inorganic matter and other impurities of GAC. All these indicate that microwave technique can effectively regenerate field-spent GAC, and hydrochloric acid pretreatment is an important process before regeneration.

Adsorption of tannic acid from aqueous solution onto surfactant-modified zeolite

Surfactant-modified zeolites (SMZs) with various loadings of cetylpyridinium bromide (CPB) were used as adsorbents to remove tannic acid (TA) from aqueous solution. The TA adsorption efficiencies for natural zeolite and various SMZs were compared. SMZ presented higher TA adsorption efficiency than natural zeolite, and SMZ with higher loading amount of CPB exhibited higher TA adsorption efficiency. The adsorption of TA onto SMZ as a function of contact time, initial adsorbate concentration, temperature, ionic strength, coexisting Cu(II) and solution pH was investigated. The adsorbents before and after adsorption were characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), thermogravimetric analysis (TGA), and Fourier transform infrared (FT-IR) spectroscopy. The adsorption kinetics of TA onto SMZ with CPB bilayer coverage (SMZ-CBC) followed a pseudo-second-order model. The equilibrium adsorption data of TA onto SMZ-CBC were well represented by Langmuir, Redlich-Peterson and Sips isotherm models. The calculated thermodynamic parameters indicated that TA adsorption onto SMZ-CBC was spontaneous and exothermic. The TA adsorption capacity for SMZ-CBC slightly decreased with increasing ionic strength but significantly increased with increasing Cu(II) concentration. The TA adsorption capacity for SMZ-CBC was relatively high at solution pH 4.0–7.0, and decreased with an increase in solution pH from 7.0 to 8.5. The mechanisms controlling TA adsorption onto SMZ-CBC at solution pH 5.5 include electrostatic attraction, hydrogen bonding and organic partitioning.

Behaviors and mechanisms of tannic acid adsorption on an amino-functionalized magnetic nanoadsorbent

Tannic acid is known as one of the refractory organic pollutants in water. Amino-functionalized magnetic nanoadsorbent (Fe 3O 4@SiO 2-NH 2) exhibited high adsorption capacity for aqueous TA with maximum adsorption amount of 136.23 mg/g at 25 °C. TA adsorption on the adsorbent could be well described by Langmuir adsorption model and the adsorption process was endothermic. Furthermore, pseudo-second adsorption kinetics can fit TA adsorption data very well, and the adsorption rate decreased with increasing initial TA concentration. The presence of Na +, K +, and Ca 2+ may result in enhanced TA adsorption. In addition, TA adsorption over the adsorbent was highly dependent on solution pH and the maximum adsorption amount was found to be at pH 6.0. The XPS analysis revealed that TA adsorption over the adsorbent may be attributed to the surface complexation between the amino groups of the adsorbent and TA in solution. The TA loaded adsorbent can be effectively desorbed in a 0.5 M HCl solution, and the regenerated adsorbent can be recycled.

Characteristics and applications of the Lagergren's first-order equation for adsorption kinetics

Adsorption kinetic curves of the Lagergren's first-order (LFO) equation were classified into four zones according to their rising characteristics. Of the 85 adsorption systems described by LFO equation, 46% of the kinetic curves belonged to zone II and 29% to zone III, these being good and fast. Activated carbons with a BET surface area of 626–1009 m 2/g and a micropore volume fraction of 57.5–88.0% were prepared from plum kernels, pinewood, pistachio shells, and Moso bamboo with steam activation. The adsorption kinetics of methylene blue, tannic acid, humic acid, and phenol on these activated carbons were studied. Normalized standard deviations were shown that the adsorption of methylene blue, tannic acid, and humic acid was better described by LFO equation and that of phenol by PSO equation. Also, the value of k 1 t ref was obviously affected by physical properties and particle sizes of the adsorbents as well as molecular weights of the adsorbates.

Adsorption studies of tannic acid by commercial ester resin XAD-7

Tannic acid and its related compounds are known as refractory organic pollutants, and it can create serious problems for the environment. The adsorption and desorption studies of tannic acid on commercial resins XAD-7 and D-201 are performed, and all data indicates resin XAD-7 can be used as an effective adsorbent for removing tannic acid during water/wastewater treatment. Furthermore, adsorption thermodynamics studies indicate different adsorption mechanisms for TA on XAD-7 and D-201. FT-IR and solid state 13C-NMR spectroscopy are used to explain the adsorption force between XAD-7 and TA. It suggests that hydrogen bonding is the main adsorption force for TA. Finally, XAD-7’s adsorption capacity in the presence of different metal ions is investigated, which indicates that heavy metal ions in solutions can decrease the adsorption capacity for TA on ester resin XAD-7.

Adsorption of tannin from aqueous solution by deacetylated konjac glucomannan

Konjac glucomannan treated by alkali solution through deacetylated reaction was used as a new water insoluble adsorbent to remove tannin from aqueous solution. A comprehensive study on adsorption of tannin by deacetylated konjac glucomannan (DKGM) was conducted regarding the effects of initial pH, adsorbent dosage, contact time, temperature and initial tannin concentration. The adsorption process was much dependent on the pH and temperature and was found to follow pseudo-second-order kinetics. The optimum pH value was at pH ranging from 2 to 6. The maximum removal efficiency of tannin from aqueous solution was 90%. Increasing the adsorption temperature would result in lower adsorption capacity, suggesting that adsorption of tannin onto DKGM was exothermic in nature. The adsorption isotherms were measured at various temperatures and correlated to Freundlich isotherms. Adsorption mechanism was confirmed that the interaction of DKGM and tannin was through hydrogen bonding. It was also observed that DKGM possesses excellent reusability for tannin removal.

Effective Lac Dyeing of Cotton Fabric by Pretreating with Tannic Acid and Aluminum Acetate

Lac dyeing of cotton fabrics pretreated with tannic acid and aluminum acetate was investigated. Five treatment methods (tannic acid alone, aluminum alone, tannic acid -> aluminum, aluminum -> tannic acid, and tannic acid luminum ->tannic acid) before dyeing with lac were compared for their effect on adsorption of the laccaic acid to cotton fabric. The treatment with tannic acid -> aluminum was found to be the most effective for lac dyeing of cotton. It was found that tannic acid enhanced the aluminum adsorption to cotton fabric, and the affinity of aluminum to laccaic acid enhanced the dyeing effect. The adsorption of tannic acid, aluminum and laccaic acid to cotton was quantitatively determined, and the dyeing mechanism was proposed.

Lac Dyeing Cotton Fibers by Pretreating with Tannic Acid and Aluminum Acetate

Lac color is one of the natural dyestuffs with an anthraquinone structure and is conveniently adsorbed to protein fibers, especially wool. Although the adsorption of lac dye to cellulose fibers is extremely low, dyeing is possible by using a mordant containing metallic ion. It is possible in such a way to obtain a deep purple color by mordant dyeing if cotton fibers are pretreated with tannic acid. The adsorption of tannic acid to cotton fibers and the relationships between tannic acid and aluminum, and aluminum and lac dye in a solution were examined to clarify this effect. It was found that the adsorption of tannic acid to cotton fibers increased the binding of aluminum to the fibers and then effectively enhanced the adsorption of lac dye. Aluminum acetate and aluminum potassium sulfate being used for the mordant in the binding ratio of aluminum to tannic acid differed. The adsorption of tannic acid to cotton was of the Langmuir type below 0.5 mM and resulted in -32.0 kJ/mol of heat of adsorption.

Initial behavior of intraparticle diffusion model used in the description of adsorption kinetics

The intraparticle diffusion model (IPD) proposed by Weber and Morris has been widely applied for the analysis of adsorption kinetics. In this work, the characteristic curves based on this model were plotted with various initial adsorption factors ( R i). Four zones of the initial adsorption according to R i value from 0 to 1 were classified; that is, approaching completely initial adsorption (zone 4), strongly initial adsorption (zone 3), intermediately initial adsorption (zone 2), and weakly initial adsorption (zone 1). Activated carbons with micropore volume fraction of 0.537 and 0.686 were prepared from oil-palm shells by steam activation. Based on the standard deviations, the kinetics of the adsorption of tannic acid (TA), methylene blue (MB), phenol, and 4-chlorophenol (4-CP) on activated carbons could be best described by intraparticle diffusion model. The initial adsorption of TA and MB belonged to zone 2, and that of phenol and 4-CP mostly belonged to zone 3. Nearly 80% of the 86 adsorption systems surveyed belonged to zones 2 and 3, indicating that the R i value was smaller when the carbon with smaller particle and steam-activated carbon was used.