Gallic Acid Removal Research Articles

Full factorial design methodology approach to optimize the elimination of gallic acid from water by coagulation using activated acorns barks as coagulant-aid

This study investigated the elimination of organic matter from water by the coagulation process using a biomaterial ?acorns barks? as a coagulantaid with the presence of aluminium sulphate in low concentration. The removal of gallic acid from water was first studied by two processes: the adsorption on activated acorns barks, and coagulation by aluminium sulphate, separately. The hybrid system was then studied, and the optimal operating conditions were determined. The performance of the hybrid system (coagulation/adsorption) mainly depends on the initial concentration of gallic acid, the coagulant dose and the mass of coagulant-aid. A full factorial design 23 was used to determine the optimum conditions for gallic acid removal. The maximum removal of gallic acid in water was 92.48 %, achieved at 20 mg L-1 of initial gallic acid concentration, 50 mg L-1 of aluminium sulphate coagulant concentration and 1.5 g of activated acorns barks adsorbent mass. The application of these optimal conditions on urban wastewater for the elimination of organic matter has shown the performance of this hybrid system treatment.

Gallic acid removal using fresh and calcined Ni-Al layered double hydroxides: Kinetics, equilibrium and response surface methodology (RSM) optimisation

ABSTRACT Emerging contaminants have recently aroused attention because of their harmful impact on ecosystem and human health. Among those contaminants, standout gallic acid which is known for its high toxicity even at low concentration. In this work, we investigated the application of Ni-Al layered double hydroxides (LDHs) as adsorbents in the removal of gallic acid from synthetic aqueous solutions. The solids were synthesised by co-precipitation method with a cationic ratio of 3. X-ray diffraction (XRD), thermogravimetric analysis (TGA), inductively coupled plasma mass spectrometry (ICP-MS), surface area measurement (N2 adsorption/desorption) and scanning electron microscopy (SEM) methods were used to characterise the adsorbents. The influence of pH, initial concentration of gallic acid and mass of adsorbent parameters were evaluated. The Brunauer–Emmett–Teller (BET) surface area increased from 107.91 to 141.33 m2/g when the sample was calcined. The adsorption experiments results showed that the pseudo-second-order model was the better kinetic model to describe the gallic acid remove. The equilibrium adsorption data were analysed using the Freundlich, Langmuir, Sips and Toth isotherm equation models. For both fresh and calcined Ni-Al-LDH, the adsorption equilibrium followed the Freundlich model. The process was endothermic, being the maximum adsorption capacities of 137.9 and 82.97 mg/g for fresh and calcined Ni-Al-LDH, respectively. The findings showed more than 94% of the gallic acid could be removed by Ni-Al-LDH calcined at 500°C. This study report also the result of response surface methodology with central composite design. This methodology was employed to optimise the effect of process variables such as pH, initial concentration of gallic acid and mass of adsorbent (m) on adsorption efficiency. Results showed that the optimised data of pH 5, initial concentration 20 mg/L and amount of 20 mg were achieved. It can be concluded that Ni-Al-LDHs are attractive materials for the treating of waters and wastewater containing emerging molecules.

Application of diatomite for gallic acid removal from molasses wastewater

In this study, diatomite was refined by a simple purification method consisting of calcination combined with acid washing. Optimal purification conditions were the focus, including the influence of conditions on diatomite morphology, structure, and specific surface area. The results showed that the optimal conditions were a 550 °C carbonization temperature and 25 wt% HCl. This purified diatomite was then employed to adsorb gallic acid (GA) from molasses wastewater in a series of adsorption experiments, which illustrated that (ḭ) GA adsorption fitted a pseudo-second-order model and the Freundlich equation better with GA adsorption by purified diatomite; (ḭḭ) the adsorption process was physical, nonspontaneous, and endothermic; (ḭḭḭ) the maximum GA adsorption capacity by purified diatomite was 19.852 mg g−1. This study reported the examination of a promising material for sugar mill wastewater pretreatment.

Adsorptive removal of gallic acid from aqueous solution onto magnetic ion exchange resin.

Finding an appropriate adsorbent with high adsorption capacity, quick adsorption kinetics and easy regeneration was crucial to the removal of gallic acid (GA) from water and wastewater. Our aims were to investigate whether a magnetic ion exchange (MIEX) resin had the three merits mentioned above, and investigate the feasibility of GA adsorption on MIEX resin, and the adsorption kinetics, equilibrium, thermodynamics, regeneration and mechanism using batch tests. The uptake of GA increased with increasing GA concentration. The GA concentration influenced the time needed to reach equilibrium, but the adsorption could be completed within 120 min. Elevating temperature facilitated the GA removal. The removal percent remained above 95.0% at pH 5.0-11.0. Carbonate and bicarbonate promoted the GA removal; conversely chloride, sulfate and nitrate restrained the GA removal significantly. The adsorption kinetics could be fitted well with the pseudo second-order model, and the film diffusion governed the whole adsorption rate. The equilibrium data followed the Redlich-Peterson isotherm model. The adsorption was a spontaneous, endothermic and entropy driven process. The ion exchange dominated the removal mechanism. The spent MIEX resin was well regenerated by sodium chloride. Therefore, MIEX resin is a potential adsorbent for removing GA quickly and efficiently from water and wastewater.

Acid – treated activated carbon for phenolic compound removal in acid pre-treatment of lignocellulosic biomass for biogas production

Phenolic compound can be an inhibitor during acid pre-treatment process in the conversion of biomass into bioenergy and consequently reduces the production yield. Thus, this study aimed to investigate the potential use of activated carbon from coconut shell for phenolic compound removal and gallic acid was used as model phenolic. Granular activated carbon was treated by using 20% concentration of phosphoric acid to its properties and function. Acid treated and untreated activated carbon were characterized in term of morphology, surface functionalities and material phase by means of SEM, FT-IR and XRD. Few parameters that influenced the removal of gallic acid were studied which included the effect of adsorbent dosage, initial concentration, contact time, and pH. It is observed that the acid treated activated carbon was successfully remove the gallic acid for about 97% using of 0.5g/L adsorbent dosage, with initial concentration of 100 mg/L, at pH value of 4 and 150 minutes contact time. The adsorption behavior was fixed with Langmuir isotherm fixed the experiment data which indicates homogenous adsorption. These experimental results also revealed that coconut shell based activated carbon is viable cheaper adsorbent for phenolic compound removal.

Process Parameters Optimization of Gallic Acid Removal from Water by MIEX Resin Based on Response Surface Methodology

In this work, the response surface methodology was used to optimize the process parameters of gallic acid adsorption on magnetic ion exchange (MIEX) resin. Based on Box-Behnken Design, a quadratic polynomial model equation including solution pH, gallic acid concentration, MIEX resin dosage and adsorption time was established. The reliability of the established regression equation was tested by variance analysis. Based on the regression equation, the technical parameters for gallic acid adsorption on MIEX resin were optimized and the effects of interaction between variables on the removal of gallic acid were analyzed. The results showed that the established regression equation was reliable and could effectively predict the removal of gallic acid. The optimal technical parameters were determined to be a pH of 9.17, a gallic acid concentration of 8.07 mg/L, a resin dosage of 0.98 mL/L and an adsorption time of 46.43 min. The removal efficiency of gallic acid was 97.93% under the optimal parameters. The interaction between pH and adsorption time had the most significant effect on the removal of gallic acid. The results of this study demonstrated that MIEX resin can remove gallic acid efficiently and relatively quickly under the condition of optimal technical parameters.

Preparation and characterization of magnetic chitosan-modified diatomite for the removal of gallic acid and caffeic acid from sugar solution

The phenolic substances in sugar cane juice affect the color value of white sugar. A magnetic chitosan-modified-diatomite (MCMD), as a new type of clarifying agent for sugar, prepared via a co-precipitation method combined with cross-linking treatment was firstly used to adsorb two primary phenolic acids of sugarcane juice: gallic acid (GA) and caffeic acid (CA). The maximum adsorption capacities for GA and CA by MCMD were 31.949 mg g–1 and 27.640 mg g–1, respectively. Additionally, our results showed that adsorption of GA and CA on MCMD fitted well with the pseudo-second-order model and Langmuir equation, respectively. The adsorption, a physical spontaneous endothermic process, might have involved electrostatic attraction and micropore filling. Importantly, MCMD has good regenerability and achieves better sulfur-free clarification of sugar cane juice and improves more significantly the food safety of white sugar than the traditional decolorization method.

A proposal for the sustainable treatment and valorisation of olive mill wastes

Olive mill technology generates a considerable amount of both solid (olive pomace OP) and liquid by-products (olive mill waste water OMWW) during olives milling season, usually between November and March. These wastes represent a great challenge for olive oil producers since they must find technical, environmental and economic solutions to manage these by-products. The aim of this work was to explore and propose a complete cycle of olive mill wastes treatment. Two sorbents based on olive pomace chemical activation, granular (GAC) and powdered (PAC) activated carbons were successfully synthetized and encapsulated in calcium alginate. The obtained gel beads (GAC-CA and PAC-CA) were tested as sorbents for gallic acid adsorption. Both sorbents showed great potential for gallic acid sorption; although PAC-CA beads resulted to be the most efficient. The major efficiency presented by PAC-CA beads for gallic acid removal was attributed to the basic character and high porosity of PAC. In view of an industrial application, PAC-CA beads were used to treat OMWW with the aim to adsorb polyphenols from the effluent, and, at time, to reduce the contamination of so strongly polyphenols loaded effluents. The outcomes of this study attest proofs of great potential of PAC-CA beads for polyphenols removal. Briefly, this paper suggests a proposal for sustainable treatment and valorization of both olive mill waste water and olive pomace, as they can be recycled and reused for own benefit of the industry.

Adsorption of gallic acid on nanoclay modified with poly(diallyldimethylammonium chloride).

In this work, particles of nanoclay modified with poly(diallyldimethylammonium), PDDA, namely PDDA/PGV, were obtained and characterized by infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X-ray diffraction (XRD), surface area measurement (BET surface area), measurement of zero charge point (pHPCZ), and scanning electron microscopy with energy-dispersive spectroscopy (SEM/EDS). The PDDA/PGV particles were applied as adsorbent for the removal of gallic acid (GA) from aqueous solution. The effect of various parameters, such as solution pH, contact time, adsorbent mass, and temperature, was studied. The maximum adsorption capacity of PDDA/PGV (238.45mgg-1) was observed at pH4 and 15°C. The study of adsorption kinetics and isotherms revealed that the adsorption process was better fitted by pseudo-first order and Freundlich model, respectively. The obtained thermodynamic parameters indicate that the adsorption of GA is spontaneous and enthalpy-driven.

Effect of calcination temperature of a copper ferrite synthesized by a sol-gel method on its structural characteristics and performance as Fenton catalyst to remove gallic acid from water

A copper ferrite synthesized by a sol–gel combustion method was calcined at different temperatures up to 800°C, determining changes in its structural characteristics and magnetic measurements and studying its catalytic performance in gallic acid removal by Fenton reaction. The main objective was to study the effect of the calcination temperature of copper ferrite on its crystalline phase formation and transformation, activity and metal ion leaching. The cubic-to-tetragonal transformation of the spinel occurred via its reaction with the CuO phase, displacing Fe3+ ions in B (octahedral) sites out of the spinel structure by the following reaction: 2Fe3+B+3CuO→Fe2O3+3Cu2+B. The catalysts showed superparamagnetic or substantial superparamagnetic behaviour. At higher calcination temperatures, catalyst activity was lower, and Cu ion leaching was markedly decreased. There was no Fe ion leaching with any catalyst. The as-prepared catalyst showed better catalytic performance than a commercial copper ferrite. Leached Cu ions acted as homogeneous catalysts, and their contribution to the overall removal mechanism was examined. Cu2O present in the as-prepared catalysts made only a small contribution to their activity. Finally, the reutilization of various catalysts was studied by performing different catalytic cycles.

Improvement of the BiOI photocatalytic activity optimizing the solvothermal synthesis

BiOI nanostructured microspheres were obtained from the solvothermal synthesis route in the presence of ethylene glycol and KI as solvent and source of iodide, respectively. Optimal conditions for the synthesis were obtained by using multivariate analysis and choosing the photocatalytic oxidation rate constant of 3,4,5-trihydroxybenzoic acid (gallic acid) as response factor under simulated solar radiation. Response surface methodology (RSM) was used to determine the optimum values of the reaction time and temperature which were 18 h and 126 °C, respectively, to obtain the most active catalyst. In addition, BiOI synthesis using ionic liquid 1-butyl-3-methylimidazolium iodide ([bmim]I) as iodide source was also carried out for the comparison of microstructure and its photocatalytic efficiency.The obtained BiOI nanostructures were characterized by scanning electron microscopy (SEM) attached with energy dispersive spectrometer (EDS), nitrogen adsorption, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermogravimetry (TG), Fourier transform infrared (FTIR) spectrometry, diffuse reflectance spectroscopy (DRS) and cyclic voltammetry (CV) analyses for their changes in morphological and structural behaviors. It was observed that the synthesis temperature of BiOI nanostructures strongly influenced the morphology, crystalline phase, surface area and electrochemical behavior, and thus affecting the photocatalytic efficiency. The higher photocatalytic removal of gallic acid (60%) was reached within 30 min of irradiation with UV-A on microspheres obtained with ionic liquid. The (1 1 0) crystal phase of BiOI influenced the photocatalytic efficiency.

Mixed iron oxides as Fenton catalysts for gallic acid removal from aqueous solutions

A study was conducted on the behavior as Fenton catalysts of three commercial mixed iron oxides: copper ferrite, magnetite, and ilmenite, using H2O2 for the degradation and mineralization of gallic acid (GA) at temperatures between 15 and 35°C and pH of 4.3. Investigation of the activity of the catalysts was complemented by study of the metal ion leaching under reaction conditions. GA was completely mineralized with the three mixed iron oxides in the following order of catalytic activity: CuFe2O4>Fe3O4>FeTiO3, and the ferrites could be quickly and completely separated after the reaction by a magnetic field. According to these results, there appears to be a synergic effect between Cu and Fe ions placed in octahedral sites, and Cu ions may be the main active sites for HO radical generation. The efficiency of H2O2 utilization followed the inverse order of the catalytic activity of the mixed iron oxides, likely because the excess hydroxyl radicals generated during the reaction were quenched by hydrogen peroxide, yielding the less reactive hydroperoxide radicals. A very large amount of Cu and Fe ions leached from copper ferrite and decreased at higher reaction temperatures. These leached ions also acted as homogeneous Fenton catalysts in GA degradation and mineralization. A much lower amount of Fe ions was leached from magnetite and ilmenite in comparison to copper ferrite. From the perspective of long-term applications, magnetite with intermediate catalytic activity but with higher efficiency and much lower Fe ion leaching in comparison to copper ferrite may be more appropriate for GA removal.

Fenton oxidation of gallic and p-coumaric acids in water assisted by an activated carbon cloth.

The objective of this study was to investigate the effect of the presence of an activated carbon cloth (ACC) during the degradation and removal of gallic acid (GA) and p-coumaric acid (pCA) by Fenton oxidation using H2O2 and FeSO4 as catalyst. Removal of GA or pCA by Fenton oxidation was much higher than that of total organic carbon (TOC), indicating that a large proportion of GA or pCA degradation products was not mineralized. The presence of ACC increased the concentration of hydroxyl radicals generated in the FeSO4 + H2O2 system. The presence of ACC during Fenton oxidation largely increased TOC and GA removal, attributable to the adsorption of GA and its degradation products and the increased generation of OH(•) radicals that mineralize them. In the Fenton oxidation of pCA, the presence of ACC produced the same effects as for GA, but now the increased removal of pCA was due to adsorption on the activated carbon and not to the increased generation of hydroxyl radicals, due to the greater affinity of pCA for the carbon surface and its more difficult mineralization in comparison to GA.

Performance of a fungal based SBR under pH extreme and shock phenolic exposure

An investigation was performed to explore the capabilities of a filamentous fungal biomass to grow non-aseptically in a glucose-fed Sequencing Batch Reactor system in very extreme environment (pH 3.5) conditions. Trichoderma viride Pers: Fr. Isolate 8/90 was used as inoculum. Microscopic investigations were carried out to confirm fungal dominance in the open culture. In batch tests, the fungal biomass showed a significant ability to grow and remove the applied organic load (2000 mg(Glucose) L(-1) d(-1)), with high biomass yields. Furthermore, the biomass showed an ability to resist gallic acid toxicity at high concentraions (1 g L(-1)) without any pre- exposure acclimation of the biomass. The biomass (about 2.5 g(VSS) L(-1)) demonstrated significant aerobic removal of gallic acid in a timeframe of 20 h from initial exposure. The robust characteristics of this SBR system demonstrate potential for future development of fungal based treatment for recalcitrant feedstocks or operation under extreme environmental conditions.

Electrochemical removal of gallic acid from aqueous solutions

Removal of gallic acid from aqueous solutions of different concentrations has been performed by electroprecipitation using a sacrificial iron anode, by indirect electrochemical oxidation carried out via electro- and photoelectro-Fenton processes using an oxygen-diffusion cathode, and by a combination of the first two methods (peroxicoagulation process). In all cases, chromatographic analyses have shown a very quick disappearance of gallic acid and its aromatic by-products within 30–90min of electrolysis, depending on the method. A pseudo first-order kinetic decay of gallic acid was always observed under galvanostatic conditions. A decay of TOC and COD close to 90 and 95% is observed with electroprecipitation and peroxicoagulation processes, respectively, after electrolysis time lower than 2h. The specific charge utilised in these two processes was about half of that theoretically required for the complete direct oxidation process (mineralisation). During electrolyses some carboxylic acids have been detected as main intermediates, which completely disappear at the end of the process, except oxalic acid in the case of electro-Fenton method.

Catalytic ozonation of phenolic compounds: The case of gallic acid

The catalytic ozonation of gallic acid has been carried out in the presence of a perovskite type material (LaTi0.15Cu0.85O3). Some of the main operating parameters like temperature, catalyst and ozone doses exerted a positive influence in the ozonation rate. Contrarily, initial gallic acid concentration showed a negative effect in terms of conversion while the optimum working pH was found to be around 2 (3.5 if deactivation is avoided). Addition of tert-butyl alcohol (free radical scavenger) had no effect on the catalytic removal of gallic acid, although its presence decreased the mineralization degree achieved. The catalyst demonstrated a high stability in terms of the acid removal, however, a partial deactivation was experienced in terms of organic carbon elimination if compared the first and second reuses. The catalyst kept its activity after further reutilisations. Due to the moderate regime developed in the homogeneous phase, the process was better simulated by an empirical expression rather than using a detailed model.

Photocatalytic ozonation of gallic acid in water

Aqueous solutions of gallic acid have been treated with five different oxidation-radiation processes: visible and ultraviolet A radiation (VUVA), TiO2 adsorption, ozonation, VUVA/TiO2 photocatalysis and VUVA/O3/TiO2 photocatalytic ozonation. With the exception of VUVA radiation and TiO2 adsorption, ozone and photolytic processes allow for the total removal of gallic acid in a period between 50 and 90 min. The time taken to achieve 100% gallic acid conversion depends on the oxidation process applied, photocatalytic ozonation being the most effective technique. Throughout the process, oxalic and formic acids were identified as byproducts. Some other unidentified compounds probably related to pyruvic, malonic and maleic acids were also detected. The appearance of these compounds can be justified from direct reactions of both hydroxyl radical and ozone in water. Only photocatalytic ozonation leads to total mineralisation of the organic matter in less than 90 min. The photocatalyst used, TiO2, showed good activity and stability (no leaching was observed) after five consecutive photocatalytic ozonation runs with the same semiconductor-catalyst mass. Copyright © 2006 Society of Chemical Industry

The Use of Glucose as a Growth Factor to Counteract Inhibition in Anaerobic Digestion

T he effect of adding gallic acid, an inhibitory compound, and mixtures of gallic acid and glucose to well mixed batch digesters and to a two-stage digestion system was examined. The results of the batch studies showed that glucose (10 and 20 mg l–1) increased both the degradation of the gallic acid and the rate at which this occurred. They also showed that gallic acid altered the amounts of ten hydrolytic enzymes in the sludge. The addition of glucose reversed this effect. The two-phase digester was operated with a hydraulic retention time of 3 hours in the acidogenic stage and 10.5 hours in the methanogenic reactor. The results showed that there was little removal of gallic acid in the acidogenic reactor. At concentrations of 10 and 20 mg l–1, gallic acid had little effect on the methane production. However, at a concentration of 50 mg l–1 there was a drop of about 15% in the volume of methane produced. The addition of glucose (15 mg l–1) reversed this effect. A similar set of results was obtained for the removal of soluble COD. An effect of adding gallic acid was to increase the concentrations of butyrate and propionate. It is not yet known how glucose operates to counteract these inhibitory effects.