Resin Dosage Research Articles

La eliminación de metales tóxicos presentes en efluentes líquidos mediante resinas de cambio iónico. Parte XIII: Zinc(II)/H+/Lewatit OC-1026

La resina de intercambio catiónico Lewatit OC-1026 (que tiene como grupo activo al acido di-2-etilhexil fosfórico adsorbido) se ha utilizado para la eliminación de zinc(II) de disoluciones acuosas. Esta eliminación se ha investigado bajo diferentes condiciones experimentales: velocidad de agitación (400-1200 min−1), temperatura (20-60 °C), pH del medio acuoso (1-4) y concentración de la resina (0,05-0,4 g·L−1). La carga de zinc(II) en la resina disminuye con el aumento de la temperatura (reacción exotérmica) en un proceso espontaneo, alcanzándose el equilibrio en tiempos mas cortos al aumentar esta variable. A 20 °C, los datos experimentales se ajustan a la cinética de pseudo-segundo orden, mientras que a 60 °C el modelo cinético que mejor representa la carga del metal en la resina es el de segundo orden. El proceso de cambio iónico depende del valor de pH del medio acuoso, disminuyendo el tanto por ciento de la carga del metal en la resina con la disminución de este valor (de 4 a 1); a pH 4, la carga del metal responde al modelo de difusión en la partícula y a la isoterma tipo-2 de Langmuir. La resina Lewatit OC-1026 presenta mejores características, respecto a la eliminación de zinc(II), que los nanotubos de carbono funcionarizados (grupos carboxílicos) y sin funcionalizar. El zinc(II) cargado en la resina puede ser eluido mediante el uso de disoluciones ácidas.

Mechanical and interface bonding properties of epoxy resin reinforced Portland cement repairing mortar

An aqueous epoxy resin with four different dosages was employed to enhance ordinary Portland cement (OPC) mortar for the first time used as a polymer-cement repairing material. Experimental results showed that the flexural toughness of the epoxy resin modified OPC mortar was obviously improved without losing too much compressive strength. In addition, three different interface bonding strengths used for evaluation of the interface bonding properties were all enhanced with certain dosages of epoxy resin. For instance, the interfacial flexural bonding strength, direct interface shear strength and interface tensile strength of the OPC mortar with epoxy resin dosage at 5% was increased by approximately 16.7%, 29.8% and 6.9% respectively compared to the control mortar without epoxy resin. It is assumed that the epoxy resin formed as polymer films which could improve the microstructure of OPC mortars as evidenced by scanning electron microscopy analysis via integrating different components in binder matrix and crack bridging effect is the main reason for the related improvements. Thus, this newly developed OPC mortar reinforced by suitable contents of aqueous epoxy resin is a promising repairing material for mitigating deteriorations of concrete which awaits further applications.

Adsorption equilibrium and kinetics studies of divalent manganese from phosphoric acid solution by using cationic exchange resin

There are numerous impurities in wet-process phosphoric acid, among which manganese is one of detrimental metallic impurities, and it causes striking negative effects on the industrial phosphoric acid production and downstream commodity. This article investigated the adsorption behavior of manganese from phosphoric acid employing Sinco-430 cationic ion-exchange resin. Resorting FT-IR and XPS characterizations, the adsorption mechanism was proved to be that manganese was combined with sulfonic acid group. Several crucial parameters such as temperature, phosphoric acid content and resin dose were studied to optimize adsorption efficiency. Through optimization, removal percentage and sorption capacity of manganese reached 53.12 wt%, 28.34 mg·g−1, respectively. Pseudo-2nd-order kinetic model simulated kinetics data best and the activation energy was evaluated as 6.34 kJ·mol−1 for the sorption reaction of manganese. In addition, the global adsorption rate was first controlled by film diffusion process and second determined by pore diffusion process. It was found that the resin could adsorb up to 50.24 mg·g−1 for manganese. Equilibrium studies showed that Toth adsorption isotherm model fitted best, followed by Temkin and Langmuir adsorption isotherm models. Thermodynamic analysis showed that manganese adsorption was an endothermic process with enhanced randomness and spontaneity.

Enhancing volatile fatty acids production from waste activated sludge by a novel cation-exchange resin assistant strategy

This study developed a novel strategy for enhancing volatile fatty acids production from waste activated sludge by cation-exchange resin assistant anaerobic fermentation. The process condition was optimized by response surface methodology. Considerable sludge disintegration degree (40.9%) and volatile fatty acids yield (4619.6 mg COD/L) were achievable at the proposed process conditions, i.e. cation-exchange resin dosage = 2.05 and 1.78 g/g SS, fermentation time = 4.97 and 6.46 d, and stirring strength = 246.9 and 261.2 rpm, respectively. Grey relational analysis revealed that cation-exchange resin dosage, fermentation time, and stirring strength presented similarly significant effects on sludge disintegration. The reusability tests showed that NaCl solution had the best effect on cation-exchange resin regeneration, and the performance of regenerated resin was comparable with the original resin on volatile fatty acids production. Compared with conventional pretreatment methods, the proposed cation-exchange resin assistant strategy revealed obvious advantages of saved pretreatment agents, easy operation, none chemical residual in sludge and small footprint. Total volatile fatty acids recovery can reach 1.46 × 108 tons chemical oxygen demand annually in terms of China’s context, which could offset one third of carbon gap in China’s wastewater treatment plants. The proposed cation-exchange resin assistant strategy indeed sheds lights on the direction for WAS treatment in a close alignment with process viability and engineering feasibility.

Clofibric acid removal by ion exchange using a magnetic ion exchange resin: equilibrium, kinetics, reusability and characterisation

ABSTRACT In this study, a commercial magnetic ion exchange (MIEX) resin was used for the removal of clofibric acid (CA), one of the most persistent pharmaceutical active compounds (PhACs) in the environment, from aqueous solutions. As a result of batch experiments, optimum conditions were determined as pH = 4–7, equilibrium time = 240 min., and resin dosage = 26 mL/L for the removal of CA with MIEX resin. Freundlich isotherm model and pseudo-second order kinetic model showed the best fit for the sorption data with correlation coefficients higher than 0.99. Thermodynamic calculations indicated that the ion exchange process betweenMIEX resin and CA was a thermodynamically feasible and spontaneous process. Regeneration studies showed that the repeated use of MIEX resin is possible. The effect of all coexistent anions (chloride, carbonate and sulphate) was found to be close to each other for molar ratios of CA:coexisting anion = 1–3. Fourier transform infrared (FTIR) spectrum and environmental scanning electron microscopy (ESEM) images were used to examine the interactions of resins with CA and to see the changes that could occur in the resins after regeneration. The most obvious changes in MIEX resin due to CA sorption are found in the 1712 cm−1, 1480 cm−1, 1238 cm−1and 963 cm−1 bands. This study revealed that the mechanism of removal of the CA by MIEX resin is ion exchange and is reversible.

Ammonia removal from low-strength municipal wastewater by powdered resin combined with simultaneous recovery as struvite

Low-strength municipal wastewater is considered to be a recoverable nutrient resource with economic and environmental benefits. Thus, various technologies for nutrient removal and recovery have been developed. In this paper, powdered ion exchange resin was employed for ammonia removal and recovery from imitated low-strength municipal wastewater. The effects of various working conditions (powdered resin dosage, initial concentration, and pH value) were studied in batch experiments to investigate the feasibility of the approach and to achieve performance optimization. The maximum adsorption capacity determined by the Langmuir model was 44.39 mg/g, which is comparable to traditional ion exchange resin. Further, the effects of co-existing cations (Ca2+,Mg2+,K+) were studied. Based on the above experiments, recovery of ammonia as struvite was successfully achieved by a proposed two-stage crystallization process coupled with a powdered resin ion exchange process. Scanning electron microscopy (SEM) and X-ray diffractometry (XRD) results revealed that struvite crystals were successfully gained in alkaline conditions (pH = 10). This research demonstrates that a powdered resin and two-stage crystallization process provide an innovative and promising means for highly efficient and easy recovery from low-strength municipal wastewater.

Uranium (VI) Recovery from Black Shale Leaching Solutions Using Ion Exchange: Kinetics and Equilibrium Studies

This work studies the removal of uranium ions from chemically leached solutions by sorption using two weak and two strong base anionites. Batch sorption experiments were performed to evaluate the optimum conditions at pH 1.2–2.2, 1.0 g resin dose for 1–12 h contact time at room temperature. These experiments addressed sorption kinetics and sorption isotherm. The maximum sorption capacity reached 55.8 mg/g at room temperature. The kinetics data are well described by the pseudo-second-order kinetic model at initial uranium concentration of 0.62 mg·L−1. To describe sorption kinetics pseudo-first-order, pseudo-second-order and intraparticle diffusion models were proposed. Studies indicated that the sorption of uranium can be fitted by a pseudo-second-order kinetic model very well. Equilibria were described by Langmuir, Freundlich, and Dubinin–Radushkevich equations. The experimental sorption isotherm is successfully described by the Langmuir model.

Recovery of non-regenerable exhausted resin by hydrothermal chlorination

Purpose Cationic resin is widely used in decolouring of textile wastewaters. Tonnes of resin are used in sector, and disposal of resin is being a second waste problem. The purpose of this paper is to investigate the adsorption behaviour of the methylene blue cationic dye from aqueous solution on the cation exchanger Lewatit CNP80 to understand the regenerability of cation exchanger resin from textile wastewaters. Design/methodology/approach Cationic resin was used as an alternative low-cost adsorbent for removing methylene blue dye from textile wastewaters. The adsorption study was carried out in the batch mode. Batch adsorption studies were carried out to examine the effect of parameters such as methylene blue concentration, temperature, pH, resin dose, shaking speed and contact time. Findings It was observed that dye-removal capacity of resin was reached from 17 mgg−1 to 19.4 mgg−1 at 25 °C temperature, pH 5 in 15 min. At the appropriate range of parameters, it was observed that more than 98% removal efficiency was achieved for methylene blue dye, and also, this study was focussed on whether the resin regenerates. In regeneration studies, our purpose was to recover of non-regenerable exhausted cationic resin by NaOCl. Regeneration of Lewatit CNP80 was performed in five cycles. After regeneration, the authors tried to determine whether the adsorption capacity was affected by regeneration. Originality/value In this study, the authors focussed on regeneration studies. The aim is to find easy, low-cost regeneration agent. In conclusion, the authors found that NaOCl is eligible for regeneration studies. The exhausted resin was recovered by NaOCl, and the authors also tested 5th regeneration cycles. Sodium hypochlorite is not a common regeneration agent for adsorption studies. Generally, resin is regenerated by HCl or other regeneration agent products. As a result of that, operational cost was reduced, and the other thing that the authors want to emphasise is textile industry wastewater based high temperature; therefore, this regeneration study can easily work with textile industries.

Kinetic Analysis and Optimum Design of Extracting Pectin from Pineapple Peel by Ion Exchange

The pectin in pineapple peel was extracted by ion exchange method. The optimum conditions of pectin extraction were obtained by single factor and orthogonal test. Under the optimal process conditions, the kinetic model was constructed by Fick’s second law, and the rate constant and apparent activation energy were obtained. The validity analysis and the model prediction ability were verified. The results show that the kinetic model can predict the kinetic process of pectin extraction from pineapple peel by ion exchange method. According to the kinetic model, the optimal conditions were obtained: the dosage of ion exchange resin was 5%, pH was 2.5, the ratio of material to liquid was 1:30 (g: mL), the extraction temperature was 85°C, the extraction time was 141.7min, and the pectin yield was 9.74%, which was consistent with the results of single factor and orthogonal test.

Ion-exchange coupled crystallization for the removal of calcium ions from dicyandiamide

A new process for ion exchange coupled crystallization is introduced for the removal of calcium ions from dicyandiamide. The effects of different ion-exchange resins, temperature, reaction time, stirring rate, and treatment amount and resin dosage on the removal of calcium ions in dicyandiamide were studied. On this basis, the crystallization process of dicyandiamide was optimized by response surface methodology, together with respective investigations on the effects of cooling rate, stirring rate, seed grain size and seeding time on the removal of calcium ions in dicyandiamide. It was found that the removal efficiency of calcium ion could reach up to 98.12%, during the ion-exchange treatment, and the value increased then fell, with the rise of stirring rate and temperature; the efficiency would improve, with the accumulation of resin dosage; but it would diminish with the increase of treatment amount; and the value would first rise and then remain unchanged when the reaction time was extended. In addition, the best conditions for crystallization are also provided. When the cooling rate is at 0.3 °C/min, the stirring rate 300 rpm, the seed size 60 meshes, and the seeding time 30 minutes, seeds in uniform size with the content of Ca2+ pharmaceutically qualified would be obtained, under the optimum process conditions.

La eliminación de metales tóxicos presentes en efluentes líquidos mediante resinas de cambio iónico. Parte XII: Mercurio(II)/H+/Lewatit SP112

El mercurio(II) puede ser eliminado de disoluciones acuosas aci­das mediante la resina de intercambio catiónico Lewatit SP112. Se ha investigado la influencia de distintas variables experimentales sobre la carga del mercurio(II) en la resina: velocidad de agitación (275–1000 min−1), temperatura (20–60 °C), valor de pH del medio acuoso (0–4) y dosificación de la resina (0.05–0.4 g·L−1). La carga de mercurio(II) en la resina disminuye con el aumento de la temperatura (reacción exotérmica) en un proceso espontaneo, mientras que el modelo de núcleo recesivo representa al mecanismo de carga del metal en el rango de temperaturas investigado. Los datos experimentales se ajustan al modelo cinético de segundo orden (275 min−1) o al modelo de pseudo segundo orden (500–1000 min−1), aunque la carga máxima del metal en la resina no depende de la velocidad de agitación. Los datos experimentales se ajustan a la isoterma tipo-2 de Langmuir. Se ha comparado la carga de mercurio(II) con distintas resinas y con nanotubos de carbono de pared múltiple. El mercurio(II) puede ser eluido con distintos eluyentes, pudiéndose obtener mercurio en estado de oxidación 0 a partir de las disoluciones de elución conteniendo al Hg(II).

Removal of Bisphenol-A using Cyphos IL-101 impregnated Amberlite XAD-7: optimisation using response surface methodology

ABSTRACTResins, when impregnated with a solvent shows better stability, higher affinity, and effectiveness in removing pollutants. The interaction of pollutants with the impregnated resin takes place by adsorption, solvent extraction, and ion exchange which enhance the resin capacity. Here, Bisphenol-A (BP-A) was removed from aqueous solution using Cyphos IL-101 impregnated Amberlite XAD-7 resin. FTIR, FE-SEM, TGA, BET, and point of zero charge analysis were used for characterisation. The experiments were designed using CCD of RSM, and an empirical model was developed to optimise input variables. The effective input parameters chosen were: resin dosage (D: 2 to 4 g/L), initial BP-A concentration (C: 30 to 50 mg/L), solution pH (P: 4 to 8), and temperature (T: 303 to 323 K) and their effect on the responses (percentage removal and adsorption capacity) were studied. At optimum conditions (D = 5 g/L, C = 58.6 mg/L, P = 8.44, and T = 294.6 K), the experimental and predicted percent removal were found to be 97.56% and 99.99%, respectively. Equilibrium and kinetic data were matched with Freundlich and pseudo-second-order model, respectively. The regenerability study showed good performance of the resin after the 5th cycle (1st use: 97.55%, 6th use: 96.21%).

Study of Pavement Performance of Thin-Coat Waterborne Epoxy Emulsified Asphalt Mixture

Waterborne epoxy emulsified asphalts (WEEA) have high densities, good chemical stabilities, and high viscosities. However, they have problems in terms of overly high stiffness and low-temperature brittleness when applied as thin-coat asphalt mixtures. In this study, testing was conducted to obtain the optimal mixing ratio for WEEA. Anti-sliding, rutting, water stability, Cantabro, and low-temperature bending tests were carried out to evaluate the performance of thin coating layers formed from open graded friction course (OGFC)-5 WEEA mixtures, with the results indicating that the optimal ratio of waterborne epoxy resin emulsion and curing agent was 2:1 and that the dosage of waterborne epoxy resin should be maintained between 15 and 30%. The surface texture depth and British Pendulum Number (BPN) of the OGFC-5 WEEA mixtures were larger than 0.91 mm and 77.4, respectively, and the WEEA mixtures had better water stabilities and spalling resistance performance than a mixture without WEEA. Waterborne epoxy resin dosages of 15 and 30% resulted in WEEA mixture stabilities of up to 4,285 and 8,798 times/mm, respectively, and tensile strengths at -10 ℃ of 2.204 and 4.727 MPa, respectively. The relatively good pavement functional and low-temperature performance of the optimized OGFC-5 WEEA mixture suggest its usefulness as a pavement maintenance material.

Potentiality of uranium recovery from G.Gattar leach liquor using Duolite ES-467 chelating resin: Kinetic, thermodynamic and isotherm features

ABSTRACTIn the present study, adsorption of uranium from sulphate solutions was performed using Duolite ES-467 aminophosphonic acid chelating resin. Batch adsorption experiments were applied to assess the optimum parameters at pH3, 0.1 g resin dose, and 200 mg/L initial U(VI) concentration, for 90 min contact time at room temperature. The maximum sorption capacity was 75 mg/g at 25°C.From kinetic parameters, it was found that U(VI) adsorption followed pseudo-first-order kinetics. Besides, the equilibrium data fitted well with the Langmuir isotherm model. The values of thermodynamic parameters (ΔH, ΔS, and ΔG) indicated that the uranium adsorption processes could be considered endothermic, randomness, and spontaneous using Duolite ES-467 resin. U(VI) waswholly eluted from the loaded Duolite ES-467 resin using 0.5 M HNO3. Finally, the optimised factors were applied for U(VI) recovery from G. Gattar for leach liquor to produce a uranium concentrate (Na2U2O7) with 70.45% U(VI) content.

Removal of malachite green, a cationic textile dye using Amberlite polymeric resins

ABSTRACT Malachite green dye was removed using three different polymeric resins (Amberlite XAD7, Amberlite 120H and Amberlite IRA67). Equilibrium and kinetic experiments were carried out to determine the effect of contact time (0–120 min), resin dose (0.05–0.4 g), initial dye concentration (10–50 mg/L), temperature (303–323 K), pH (2–12) and NaCl concentration (0.5–50 g/L) on the adsorption capacity of all the resins. With an increase in the resin amount, a sharp decrease in the adsorption capacity was observed. The removal efficiency of dye was found to be 98.29% with IRA67, 99.27% with XAD7, and 98.66% with IR120H after 120 min. Temkin isotherm matched equilibrium data for XAD7 and IR120H, whereas Freundlich isotherm model best described the results for IRA67, pH, temperature and NaCl did not affect the removal efficiency significantly. Kinetic data were well fitted with pseudo-second order rate kinetics. All the three resins were regenerated using 1 M NaOH solution showing good reusability.

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.

Characterization of Fresh and Cured Properties of Polymer Concretes Based on Two Metallurgical Wastes

Polyester polymer concretes can substitute conventional concretes based on their usually good mechanical strength, adequate physical properties, and high resistance against aggressive chemical environments. They also show a high potential for using recycled targets in their manufacturing. This paper analyzes the fresh and cured properties of polyester polymer concretes containing two metallurgical wastes, namely: ladle slag and alumina filler. Both targets require a higher resin dosage than sand. The standard consistency test showed a low representativeness of the recycled fresh mixes’ workability. The ladle slag and alumina filler samples showed a higher length plastic shrinkage than those containing sand. All of the targets obtained cured density values in the range of 1.589–1.912 g/cm3. From a mechanical point of view, the sand and alumina filler containing polyester polymer concretes reached 11.02 and 10.93 kN, respectively, of flexural strength, while the ladle slag samples showed the best result with 19.31 kN. In the compressive strength test, the sand and alumina filler combinations reached 106.16 and 104.21 MPa, respectively, while the ladle slag achieved 160.48 MPa. The flexural and compressive elasticity modulus showed similar trends related to the resin content.

La eliminación de metales tóxicos presentes en efluentes líquidos mediante resinas de cambio iónico. Parte XI: Cobalto(II)/H<sup>+</sup>/Lewatit TP260

Este trabajo investiga sobre la eliminación de cobalto(II) presente en medios acuosos mediante la resina de cambio iónico Lewatit TP260. El sistema se estudia bajo distintas condiciones experimentales: velocidad de agitación (300-1400 min-1), temperatura (20-60 ºC), pH del medio acuoso (1-5), dosificacion de la resina (0.07-0.5 g·L-1) y fuerza iónica de la disolución acuosa. El metal se carga en la resina mediante una reacción de intercambio catiónica en un proceso endotérmico y espontáneo. Esta reacción de intercambio se define por un proceso de difusión en la disolución acuosa y el modelo cinético de pseudo-primer orden (20 ºC) y el modelo cinético de pseudo-segundo orden (60 ºC), asimismo los resultados experimentales se ajustan bien a la isoterma de Langmuir. Los resultados experimentales del sistema se han comparado con los obtenidos con otras resinas de intercambio cationico y también con nanotubos de carbono de pared multiple oxidados y sin oxidar. Se estudia la selectividad del sistema Co(II)-Lewatit TP260 con respecto a la presencia de otros cationes (disoluciones binarias Co-metal) en el medio acuoso). El cobalto(II) cargado en la resina se puede fluir con disoluciones ácidas (HCl o H2SO4).

Separation and recovery of iron and scandium from acid leaching solution of red mud using D201 resin

Red mud is a byproduct of alumina refining of bauxite ores, and is a significant source for extracting scandium. However, a large amount of iron in red mud makes it difficult to recover scandium because Fe(III) and Sc(III) have similar physicochemical properties. In this study, a new method was developed for selective separation of iron and scandium in acid leachate of red mud using D201 resin. Theoretical calculations indicate that the ferric species mainly exists as FeCl3 or FeCl4− at chloride concentration above 6.65 mol/L, while scandium still exists as ScCl2+, making it possible to selectively separate iron from scandium through anion resin adsorption. The factors affecting the adsorption of iron and scandium such as chloride concentration, resin dosage, adsorption time, and temperature were evaluated in batch experiments. The Langmuir model was successfully applied to both iron and scandium adsorption, and the maximum adsorption capacities of iron and scandium are 147.06 and 0.95 mg/g, respectively, indicating a significant difference between iron and scandium. Raman analysis further demonstrates that the iron is adsorbed onto D201 resin as FeCl4− anion.

Treatment of monazite processed effluent to recover rare earth metals (REMs)

Improper disposal of effluent generated in rare earth mining areas and ore processing industries results in loss of REMs and miserably affects the ecosystem. Thus, their appropriate treatment is required, which can be achieved via environmentally feasible processes. In this connection, systematic scientific adsorption studies were carried out to separate REMs using cationic resin, Amberlite IR120 Na from the effluent generated during monazite processing for REMs recovery. To optimize feasible conditions for REMs recovery, bench scale studies were carried out varying different process parameters viz. pH, contact time, resin dose, etc. It was observed that adsorption of 92.63% La, 92.79% Ce, 91.45% Nd, 90.95% Pr and 95.09% Sm was achieved at aqueous/ resin (A/R) ratio 25 mL/g, pH 1.3 and contact time 10 min. Loading capacity of resin was found to hold 48.57 mg REMs/g resin. The adsorption data followed the second order reaction ((t/q) = (1/h) + (1/qe)(t)) and Langmuir adsorption isotherm (1/q = [(1/k1 qm)(1/Ce)] + (1/qm)). The loaded REMs was effectively eluted using 15% H2SO4 in 10 min. The REMs enriched solution was treated to get pure REM oxides as precipitate. This technical application will be useful for REMs recovery as well as to mitigate environmental pollution.