Anionic Resin Research Articles

Regeneration of a Fire‐Resistant Fluid‐Fouled Strong Base Anion Resin using a Caustic Solution with Citric Acid as a Surfactant

AbstractFire Resistant Fluid (FRF), used in turbine governing systems, transforms during operation, forming substituted phenol and phosphoric acid. The use of strong Base Anion Resin (SBA resin) to reduce the Total Acid Number (TAN) of FRF is widespread. However, the regeneration of these oil‐fouled resins is crucial due to their high cost and the challenges associated with their environmental disposal. In this study, we present a novel method for recovering exhausted resin by treating it with an aqueous solution of citric acid, followed by regeneration with a caustic soda solution. We optimized the recovery percentage in the ion exchange capacity by testing varying concentrations of the citric acid solution under different reaction conditions. The highest recovery of ion exchange capacity achieved was 55 % after soaking for 16 hours in a 5 % citric acid solution, followed by regeneration with a 5 % NaOH solution. The efficacy of citric acid in this research was further explored through a Density Functional Theory (DFT) study. This study is significant as it is the first to demonstrate the successful regeneration of oil‐fouled resins with high ion exchange capacity using citric acid, a more environmentally friendly and cost‐effective alternative.

Recovery of carboxylic acids from actual effluent by using sequential cationic-anionic adsorption steps at semi pilot scale

This work presents for the first time an exhaustive experimental assessment at semi-pilot scale for the sequential use of cationic-anionic adsorption columns for recovering carboxylic acids (CAs) from a real fermentation broth. The consecutive steps were dedicated to i) remove cations limiting the CAs interaction with the functional group of the anionic resin, and ii) adsorb CAs onto the anionic resin, respectively. The experimental broth was obtained from anaerobic co-fermentation of urban biowaste (UBW-broth). Breakthrough (BT) tests were firstly performed with the cationic column containing the strong-acid resin Lewatit® S2568H. This allowed both to assess the single process and to prepare 60 L of decationised UBW-broth to be used in the BT-tests with the anionic column (containing the weak-basic resin Lewatit® A365). Both columns were assessed (at 25°C) under packed and expanded bed modes, by feeding at different rates the actual UBW-broth or synthetic solutions. Main study innovative outputs were: 1) 100 % of the CAs occurring in UBW-broth were recovered with the proposed system; 2) best performances were obtained under expanded bed mode of operation, allowing to use 100 % of the installed capacity; 3) the affinity of other organic matter else than CAs resulted weaker than Na+/NH4+ and CAs/PO4x-/Cl- in both cationic and anionic columns, respectively (i.e. low adsorption performances generally reported are due to inorganic cations/anions presence); 4) a very preliminary economic analysis carried out on the basis of the obtained data indicates overall costs ranging 0.58–1.49 EUR/kg of CAs (depending on the process configuration).

Sorption of zinc chloride complexes from acid-based solutions by using anionic resins: process optimization and modelling

The sorption of zinc chloride ions from hydrochloric acid-based solutions using anionic resins was investigated. A two-stage experiment was planned. In the first stage, parameter optimization was performed using the Taguchi experimental optimization approach for type of anionic resins, initial Zn (II) ion concentration, resin dose, agitation rate, and temperature and time of the process as process parameters. According to the signal—to—noise ratio values calculated with the larger better-quality feature; the optimum parameter levels were determined as chloride form resin, 10 g/L, 1200 mg/L, 200 rpm and 35 °C and 90 min, respectively. Under optimum operating conditions, the sorption capacity of the resin for zinc chloride complex ions was 46.52 mg/g. The energy dispersive X-Ray analyses confirmed that zinc chloride complexes bind to the resin’s surfaces. In the second step, equilibrium and kinetic tests were performed under the optimum parameters. The tests results were compared with six equilibrium isotherm models with 2 or more parameters and four kinetic models. The non-linear solution approach was applied for all models. Langmuir isotherm and the general order models were the best fit. The values of KL\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${K}_{L}$$\\end{document} and qm,L\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${q}_{m,L}$$\\end{document} for the Langmuir model were 2.15*10–3 L/g and 66.08 mg/g, respectively. The kinetic model can be given by an equation of order 3.26. Accordingly, kn\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${k}_{n}$$\\end{document} and qe,n\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${q}_{e,n}$$\\end{document} were 2.18*10–5 min/(g mg)2.26 and 60.03 mg/g, respectively. The process mechanism was a typical chemical sorption. According to the results of desorption tests conducted using 1 M HCl, the desorption efficiency was 65%.

A New Approach of Complexing Polymers Used for the Removal of Cu2+ Ions.

This study presents two modified polymers for Cu2+ ion removal from aqueous media. Shredded maize stalk (MC) and a strong-base anionic resin (SAX) were modified with indigo carmine (IC) in order to obtain two different complexing polymers, i.e., IC-MC and SAX-IC. Initially, the complex reaction between IC and Cu2+ in the solution was studied. Additionally, the complex formation Cu2+-IC in liquid solutions was evaluated at different pH ranges of 1.5, 4.0, 6.0, 8.0, and 10.0, respectively. For Cu2+ ions, adsorption onto the IC-MC and IC-SAX batch experiments were conducted. The contact time for evaluating the optimum adsorption for Cu2+ ions on the complexing materials was established at 1 h. Efficient Cu2+ ion adsorption on the IC-MC and SAX-IC at pH = 10 was achieved. The adsorption of Cu2+ ions depends on the quantity of IC retained on MC and SAX. At 2.63 mg IC/g MC(S4) and 22 mg IC/g SAX(SR2), a high amount of Cu2+ ion adsorption was reported. The highest adsorption capacity (Qe) of IC-MC was obtained at 0.73 mg/g, and for IC-SAX, it was attained at 10.8 mg/g. Reusability experiments were performed using the HCl (0.5 M) solution. High regeneration and reusability studies of IC-MC and IC-SAX were confirmed, suggesting that they can be used many times to remove Cu2+ ions from aqueous matrices. Therefore, the development of complexing materials could be suitable for Cu2+ ion removal from wastewater.

Effects of Drying Process and High Hydrostatic Pressure on Extraction of Antioxidant Ergothioneine from Pleurotus citrinopileatus Singer.

This study evaluated the effects of different drying techniques on the physicochemical properties of Pleurotus citrinopileatus Singer (P. citrinopileatus), focusing on the ergothioneine (EGT) contents. The P. citrinopileatus was subjected to natural ventilation drying (ND), freeze-drying (FD), and hot-air drying (HD). EGT was extracted using high-hydrostatic-pressure extraction (HHPE), and response surface methodology (RSM) was employed with four variables to optimize the extraction parameters. The crude EGT extract was purified by ultrafiltration and anion resin purification, and its antioxidant activity was investigated. The results showed that the ND method effectively disrupted mushroom tissues, promoting amino acid anabolism, thereby increasing the EGT content of mushrooms. Based on RSM, the optimum extracting conditions were pressure of 250 MPa, extraction time of 52 min, distilled water (dH2O) as the extraction solvent, and a 1:10 liquid-solid ratio, which yielded the highest EGT content of 4.03 ± 0.01 mg/g d.w. UPLC-Q-TOF-MSE was performed to assess the purity of the samples (purity: 86.34 ± 3.52%), and MS2 information of the main peak showed primary ions (m/z 230.1) and secondary cations (m/z 186.1050, m/z 127.0323) consistent with standard products. In addition, compared with ascorbic acid (VC), EGT showed strong free radical scavenging ability, especially for hydroxyl and ATBS radicals, at more than 5 mmol/L. These findings indicate that the extraction and purification methods used were optimal and suggest a possible synthetic path of EGT in P. citrinopileatus, which will help better explore the application of EGT.

Adsorption of Ag(Ⅰ) on chelate resins containing N and S: Comparison and computational study with anionic resin

Chelate resins containing N and S atoms have a strong affinity for silver ions Ag(Ⅰ). In order to compare the effects of different functional groups on adsorption performance, two thiourea based isomeric resins containing S and N atoms (D840 and TMMR) were applied. And considering the silver-containing wastewater in photography, a thiosulfate system and tertiary amino anion resin D301 were used to compare the influence of external factors and specific adsorption mechanism. The adsorption properties were conducted using static experiments. FTIR, FESEM, BET and XPS were used to analyze the resins before and after adsorption. Thermodynamic and kinetic model fitting and DFT theoretical calculations were also carried out. Acidic conditions (pH = 2.0 to 5.0), adsorption dose of 1.5 g/L and reaction time (10–12 h) are beneficial for Ag(Ⅰ) adsorption. The adsorption of Ag(Ⅰ) by resins are more consistent with Langmuir isothermal adsorption model and pseudo-second-order kinetic adsorption model. Inferring from DFT calculation that the adsorption is mainly due to the chelation of S and N and the protonation of N. TMMR prepared by grafting thiourea onto the chlorine sphere matrix has the strongest activity, which is consistent with the experimental results that its maximum adsorption capacity could reach 602.1 mg/g under room temperature, exhibiting excellent application potential. It was inferred that dual mechanism of chelation and N protonation can exhibit better adsorption performance compared to a single action, but chelation has slightly poorer cycling stability compared to N protonation. This work mainly lies in the systematic comparison of Ag(Ⅰ) adsorption on chelate resins and anionic resin, and the study of adsorption mechanism by combining DFT theoretical calculation, forming a complete closed-loop research system and enriching the analysis process.

The kinetics of tungsten adsorption from acid leaching solution of scheelite by anion resin

The adsorption kinetics of tungsten from acid leaching solution of scheelite was investigated. The effects of solution pH value (3.0–9.0), anion resin dosage (1–6 g), contact time (20–180 min) and reaction temperature (20–60 °C) on the tungsten adsorption were studied. The results showed that the tungsten adsorption was practically independent of reaction temperature at the investigated range, while increasing with the increases of resin dosage and contact time, and the decreases of solution pH value. The experimental data agreed quite well with the Langmuir model, with the maximum adsorption capacities of tungsten is 347.34 mg/g at 20 °C. In addition, SEM-EDS analysis further revealed that tungsten was well adsorbed by the anion resin.

Adsorption properties and kinetics of organic acids in yellow rice wine by weakly basic anionic resins based on membrane separation

Abstract Yellow rice wine (Huangjiu) is a traditional alcoholic beverage in China. This study aimed to find a new method to reduce the acidity of Huangjiu. Three membranes with different molecular weight cut-offs (200, 1000, and 2000 Da) were selected to separate small molecules in Huangjiu, and then the adsorption of four models of weakly basic anion-exchange resins (335, D301, D314, and D354) on the organic acids in the filtered fractions of Huangjiu was investigated. The D354 resin exhibited the highest adsorption rate of 157.74 mg/g and the adsorption of acids was more consistent with the proposed second-order kinetic model. The adsorption capacity of D354 resin decreased with increasing temperature, and the adsorption of D354 resin correlated better with the Freundlich isotherm model. The initial deacidification efficiency of the D354 resin was 91.52% and it decreased by 3.88% after 10 regenerations. After the D354 resin treatment, the total acid content decreased by 56.11%, and the retention rates of amino acids and volatile substances reached 97.96% and 81.93%, respectively. The results showed that D354 resin could be used for the deacidification of Huangjiu. Membrane separation combined with resin adsorption process provides a new method to reduce the acidity of Huangjiu, which helps to maintain the flavor of the deacidified Huangjiu while efficiently reducing the acidity.

Xylitol Production by Debaryomyces hansenii in Extracted Olive Pomace Dilute-Acid Hydrolysate

The extracted olive pomace (EOP) is an industrial lignocellulosic by-product of olive pomace oil extraction, currently mainly used for energy production through combustion. In this work, the hemicellulosic fraction of EOP was selectively hydrolyzed by diluted acid hydrolysis to obtain pentose-rich hydrolysates that can potentially be upgraded by Debaryomyces hansenii, targeting xylitol production. The monosaccharides and degradation by-products released along the pre-treatment were quantified and several detoxification methods for the removal of potentially toxic compounds were evaluated, including pH adjustment to 5.5, the use of anion-exchange resins, adsorption into activated charcoal, concentration by evaporation, and membrane techniques, i.e., nanofiltration. The latter approach was shown to be the best method allowing the full removal of furfural, 41% of 5-hydroxymethylfurfural, 54% of acetic acid, and 67% of the phenolic compounds present in the hydrolysate. The effects of the supplementation of both non-detoxified and detoxified hydrolysates were also assessed. The non-detoxified hydrolysate, under aerobic conditions, supported the yeast growth and xylitol production at low levels. Supplementation with the low-cost corn steep liquor of the nanofiltration detoxified hydrolysate showed a higher xylitol yield (0.57 g/g) compared to the non-detoxified hydrolysate. The highest xylitol productivity was found in hydrolysate detoxified with anionic resins (0.30 g/L·h), which was 80% higher than in the non-detoxified culture medium. Overall, the results showed that EOP dilute acid hydrolysates can efficiently be used for xylitol production by D. hansenii if detoxification, and supplementation, even with low-cost supplements, are performed.

Nanometer lanthanum hydroxide modified anionic polymer for deep fluoride removal: Adsorption properties and mechanism study

The development of chemical industry has brought about serious fluoride pollution, and there is an urgent need to develop an adsorbent with high efficiency and stability for fluoride removal. Despite the remarkable adsorption capacity of lanthanum hydroxide hydrate for fluoride ions, its industrial application is limited by powder leaching and strict pH requirements.In this study, lanthanum-containing anionic resin (HLO-D201) was synthesized by the method of precursor introduction and in-situ deposition, mainly by introducing La3+ into the resin, adding sodium hydroxide to precipitate it in the resin pore, forming hydrated lanthanum oxide.The characterization analysis showed that hydrated lanthanum oxide (HLO) was successfully introduced into the porous matrix of the resin and existed in the form of crystalline hydrated oxide.Static adsorption experiments demonstrated that HLO-D201 could effectively adsorb fluoride ions in a wide pH range (2–10). Since nano La (OH) 3 was encapsulated in the resin pore, the loss of La (OH) 3 was greatly reduced, and under the condition of competitive adsorption of several coexisting ions, Only phosphoric acid group interferes obviously with the adsorption of F-. The synthesized HLO-D201 still showed good adsorption capacity after regenerated by NaOH–NaCl composite solution for six times. The removal mechanism of fluoride by HLO-D201 is mainly electrostatic attraction and ligand exchange.Overall, HLO-D201 is a kind of fluorine removal adsorbent with excellent performance and wide application prospects.

Characteristics of Algerian Goat's Milk

Goat milk, which is very popular especially in France where many famous cheeses are made, could meet the needs of people living in the mountains, and can be eaten fresh or processed. However, for the latter case, it is established that only milk with α S1-casein expressed with a high percentage could result in the manufacture of cheese. For this, we conducted a study that aims in a first step to assess the physical and chemical characteristics of goat milk collected in three regions of Tizi-Ouzou. The analysis performed has carried on the pH, acidity, total solids, proteins, fat, lactose and vitamin C. The results obtained for these parameters, including total solids (109.3 g / l), fat (30.7 g / l), lactose (39.1 g / l) and proteins (26g / l), are state of the good nutritional value of milk collected locally. However, the levels obtained were below those of bovine milk analyzed under the same conditions. In a second step, we performed the isolation and characterization of proteins. For this, we used the precipitation of the casein at their isoelectric pH (pH 4.2) followed by ion exchange chromatography on DEAE-cellulose. The fractions were then checked by polyacrylamide gel electrophoresis under different conditions (native, in the presence of urea, in the presence of SDS). The resulting electrophoretic profiles have identified similarities between goat and cow milk as they have helped to highlight some particularities including both caseins (αS) as serum proteins (PP3, α-La and β-Lg). The use of weak anionic resin in a single chromatographic separation step is advantageous in that it led to the isolation of goat protein (casein β, casein α S, PP3, SA and β-Lg) with a high degree of purity.

Enterobacter aerogenes Lipase immobilized on ion exchange resin D152 as a supportive carrier

Enterobacter aerogenes Lipase used in this study was heterologously expressed by Pichia pastoris. D152, D152H, D151H, D113, 724), three types of anion resins ( D380, D 301R, D311) and two types of chelating r activities of the immobilized ( EAL). According to the results, D152 was selected for haydrolysis activity as the immobilized enzyme (EAL) . The D152 was selected for hydrolysis activity since the immobilized lipase exhibited the highest specific hydrolysis activity. Immobilization conditions (enzyme loading, immobilization time, temperature, and pH value) . The best results were enzyme loading 4mg/g, time 80min, temperature 30°C, and buffer pH 8; and under the optimized conditions the immobilization efficiency was 95% and the specific activity was 532841.34 U/g.esins (D401, D418) were sieved as support matrix. Hydrolysis assay was employed to evaluate the specific.

Insights into the adsorptive separation of iron from pickling waste acid: The overlooked role of FeCl3 species

Elucidating the dominant adsorption species of FeCln3−n is fundamental for precisely regulating the adsorption process and thus enhancing the management of waste pickling liquor. In this work, anion resin (D201) exhibits great adsorption for FeCl4−, also exhibits the unexpectedly high adsorption for neutral species FeCl3. The contribution of various iron species was quantitatively evaluated via Ion Species Contribution Evaluation (ISCE). The results illustrate that both FeCl3 and FeCl4− were the dominant species adsorbed by D201 resin and exhibited similar adsorption activities. Experimental and computational results indicate that the adsorption of FeCl4− is accompanied by the shedding of Cl on FeCl4− and FeCl3 recombines with the Cl on D201, which indicate that FeCl3 is an intermediate species in the FeCl4− adsorption process. Accordingly, FeCl3 was revealed to be critical species for iron adsorption in hydrochloric pickling liquor. The concentration of HCl (20 % w/w) required for FeCl3 was sufficient for the removal of iron compared with the higher concentration (25 % w/w) required for FeCl4−, which broadened the concentration boundary for HCl reuse. Our strategy serves for industrial iron removal from hydrochloric pickling liquor and results in 86 % reduction in the amount of hydrochloric acid during 100 days pilot-scale test.

Antibody sequence-based prediction of pH gradient elution in multimodal chromatography

Multimodal chromatography has emerged as a promising technique for antibody purification, owing to its capacity to selectively capture and separate target molecules. However, the optimization of chromatography parameters remains a challenge due to the intricate nature of protein-ligand interactions. To tackle this issue, efficient predictive tools are essential for the development and optimization of multimodal chromatography processes. In this study, we introduce a methodology that predicts the elution behavior of antibodies in multimodal chromatography based on their amino acid sequences. We analyzed a total of 64 full-length antibodies, including IgG1, IgG4, and IgG-like multispecific formats, which were eluted using linear pH gradients from pH 9.0 to 4.0 on the anionic mixed-mode resin Capto adhere. Homology models were constructed, and 1312 antibody-specific physicochemical descriptors were calculated for each molecule. Our analysis identified six key structural features of the multimodal antibody interaction, which were correlated with the elution behavior, emphasizing the antibody variable region. The results show that our methodology can predict pH gradient elution for a diverse range of antibodies and antibody formats, with a test set R² of 0.898. The developed model can inform process development by predicting initial conditions for multimodal elution, thereby reducing trial and error during process optimization. Furthermore, the model holds the potential to enable an in silico manufacturability assessment by screening target antibodies that adhere to standardized purification conditions. In conclusion, this study highlights the feasibility of using structure-based prediction to enhance antibody purification in the biopharmaceutical industry. This approach can lead to more efficient and cost-effective process development while increasing process understanding.

Isomerization of Hemicellulose Aldoses to Ketoses Catalyzed by Basic Anion Resins: Catalyst Screening and Stability Studies

Isomerization of aldoses to ketoses is an essential step in carbohydrate valorization routes in biorefineries to produce a wide variety of bioproducts. In this work, selective isomerization of aldoses into ketoses was investigated using different commercial Brønsted basic anion resins at low temperature conditions. Weak and strong basic resins were tested under different reaction conditions. Amberlite IRA-900 and Amberlyst A-26 (strong resins) and Amberlite IRA-67 and Amberlyst A-21 (weak resins) were tested to assess their catalytic properties. Strong basic resins provided high yields of fructose. IRA-900 was also tested in the isomerization of different sugar monosaccharides conventionally present in lignocellulosic biomass (xylose, arabinose, galactose, glucose and mannose) aiming to explore the performance of this material in hemicellulose-derived sugar mixtures. Very promising performance was observed for IRA-900, yielding fructose selectivity higher than 75% and fructose yield of 27% in the isomerization reaction. Notably, basic anionic resins were not suitable for reuse in different reaction cycles, although the use of organic cosolvents, specifically ethanol, improved the reusability of the tested resins.

Design considerations for biological ion exchange drinking water filters: Resin selection, backwash, and regenerations

AbstractTwo pilot studies provide insights into the design and operations of biological ion exchange (BIEX) drinking water filters. A lab‐scale pilot with strong‐base anionic (SBA) and weak‐base anionic (WBA) resins demonstrated 35% and 31% removal of dissolved organic carbon (DOC) up to 30 months, until secondary ion exchange exhaustion. While the WBA resins exhibited 14% less removal of DOC, their larger capacity doubled the duration until filter exhaustion. WBA filters were less affected than their SBA counterparts by sulfate‐containing inlet waters. In a second pilot, while water with high DOC yielded rapid exhaustion of SBA resins, air scouring increased the breakup of filter media and improved solids removal by 30× compared to hydraulic backwash alone. Significantly, DOC removal improved by 36% for a week following air scour. Key recommendations include the use of WBA resins to extend operating life while implementing air scouring can dramatically improve short‐term DOC removal.

New Eco-Friendly and Low-Energy Synthesis to Produce ZnO Nanoparticles for Real-World Scale Applications.

This paper presents an original and sustainable method for producing ZnO nanoparticles (NPs) in response to global challenges (low energy requirements, low environmental impact, short production times, and high production yield). The method is based on an ion exchange process between an anionic resin and an aqueous ZnCl2 solution; it operates in one step at room temperature/ambient pressure without the need for complex apparatus or purification steps. From the kinetics, we observed the formation of pure simonkolleite, a zinc-layered hydroxide salt (Zn5(OH)8Cl2·H2O), after only 5 min of reaction. This compound, used elsewhere as a ZnO precursor after calcination at high temperatures, here decomposes at room temperature into ZnO, allowing extraordinary savings of time and energy. Finally, in only 90 min, pure and crystalline ZnO NPs are obtained, with a production yield > 99%. Several types of aggregates resulting from the self-assembly of small hexagonal platelets (solid or hollow in shape) were observed. Using our revolutionary method, we produced almost 10 kg of ZnO NPs per week without any toxic waste, significantly reducing energy consumption; this method allows transferring the use of these unique NPs from the laboratory environment to the real world.

Evaluation of the adsorption behavior of mixed perfluoroalkyl and polyfluoroalkyl substances onto granular activated carbon and styrene‐divinylbenzene resins

AbstractBecause of the remarkable chemical structure of perfluoroalkyl and polyfluoroalkyl substances (PFAS), as well as the complex conditions of water, selecting an appropriate adsorbent for treating PFAS is critical. Adsorption needs to be environmentally friendly, low cost, and consider the types of adsorbents that work well in mixed PFAS solutions. In the present study, we used mixed PFAS to estimate the PFAS activity. This research aimed to evaluate and compare the efficacy of the adsorption of PFAS from water using different adsorbents: granular activated carbon (GAC), IRA 910 (strong anion resin), and DOWEX MB‐50 (mixed exchange resin). Batch adsorption isotherms and kinetic studies were performed for perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), and perfluorohexane sulfonic acid (PFHxS). Freundlich models consistently described the kinetic behavior with a high correlation coefficient (R2 > 0.98). PFAS adsorption capacities on GAC and IRA910 were dependent on the chain length (PFOS > PFOA > PFHxS). The adsorption capacity of DOWEX MB‐50 decreased because of the sulfonate effects (PFOS > PFHxS > PFOA). The rate constants (k2) that represented the adsorption of PFAS on different adsorbents observed within 96 h were accurately determined by the pseudo‐second‐order (PSO) model. GAC achieved followed the relationship k2(PFOS) > k2(PFOA) > k2(PFHxS). Furthermore, k2 of IRA910 decreased in the order of k2(PFOA) > k2(PFOS) > k2(PFHxS), implying that IRA910 promoted hydrophobicity more significantly on the adsorption of PFCAs than perfluoroalkane (‐alkyl) sulfonic acids. The kinetics of DOWEX MB‐50 revealed k2(PFHxS) > k2(PFOS) > k2(PFOA) because gel‐type resins like DOWEX MB‐50 are more suitable for shorter‐chain PFAS. Further investigation is needed to determine the effect of organic matter under natural conditions and evaluate adsorptive selection caused by operational complexities.

Experimental study of order and constant rate of chlorine removal reaction using ion exchange resin

In this research, a strong anionic resin was prepared to remove chloride ions. This study was performed in a laboratory pilot to evaluate effective parameters such as temperature, amine flow rate, pH, chloride ion concentration and concentration of resin caustic. The purpose of this work is to determine kinetics of the resin reaction and determination of the optimal operating conditions in order to achieve maximum saturation. This study shows that volume of distilled water passing through resin to eliminate alkalinity at temperatures 40 °C, 50 °C and 60 °C is equal to 5500 ml, 5000 ml and 7000 ml, respectively. This work states that a temperature 50 °C is more appropriate than other temperatures. The results of this research show that volume of caustic for resin recovery is 8.5 L at a temperature of 50 °C. This study shows that amount of distilled water to eliminate alkalinity of the resin is equal to 5 L. Results show that the order of reaction to chloride ion concentration is equal to 0.794 and reaction constant is equal to exp (−1.8753).

Complex coacervation behavior between cationic polyamides and anionic epoxy resins endowed improved cold-pressing performance of soy protein adhesive

The weak internal cohesion and initial viscosity of soy protein adhesives lead to the poor cold-pressing bonding performance of plywood preparation. This deficiency restricted the assembly efficiency during the sizing process. In this work, we report that electrostatically induced “coacervation behavior” between anionic and cationic resins can be considered a facile strategy to guide the preparation of a high-temperature soy meal (HSM)-based adhesive with improved cold-pressing bonding performance. A robust internal cohesive framework was aided by multiple interactions (e.g., electrostatic interactions, cation-π interactions and hydrogen bonding) with the combination of polyanionic carboxyl-grafted waterborne epoxy resin (WEU) and cationic polyamides resin (PAE) in HSM matrix. The resultant adhesives exhibited improved initial viscosity with cold-pressing bonding shear strength at 1.17 MPa, which is 200.0% higher than that of the pristine HSM adhesive. Ring-opening reactions occurred in the adhesive system under hot-pressing, and the chemical crosslinking network rendered the excellent water-resistance of the adhesives. The maximum wet shear strength of the plywood reached 1.62 MPa, meeting the fundamental requirements (0.7 MPa) for its industrial application. Given its improved cold-pressing and wet bonding shear strength, this effective and novel coacervation strategy is promising to pave the way for high-performance soy protein-based composites in plywood manufacturing.