Poly Styrene-divinylbenzene Research Articles

Combination of atom transfer radical polymerization and alkyne-azide click-chemistry for the synthesis of phosphonic acid cation exchange materials.

Phosphonic acid cation exchange materials (PCX) are synthesized by atom transfer radical polymerization (ATRP) followed by alkyne-azide click-chemistry. ATRP is used to synthesize polymeric chains of diethyl 4-vinylbenzylphosphonate with different chain lengths, which are covalently bonded to the surface of monodisperse polystyrene-divinylbenzene (PS/DVB) particles by click-chemistry. The functionalized particles are characterized by FIB-SEM, IR and Schoeniger combustion followed by chromatographic experiments. The effect of chain length on chromatographic behavior is investigated by comparing four PCX columns with different chain lengths. Polar ionic pesticides and non-polar triazines are used as model analytes for chromatographic characterization. The chain length showed an influence on the retention of doubly charged analytes, which can be explained by the increased local charge density with longer chains. The resolution of the constitutional isomers prometryn and terbutryn increased with the chain length, leading to an isocratic separation of seven triazines in 35 min. They also showed secondary interactions with the polymeric support material that are not influenced by capacity or chain length.

Synthesis of some anion exchange resins for selective separation of 99Mo and 131I: A comparative study

ABSTRACT Amination of styrene-divinylbenzene (SDVB) copolymers is a traditional process for preparing strong anion exchange resins that can greatly improve their performance and applications. In the present investigation, poly(styrene-co-divinyl benzene) copolymers functionalized by various amino groups were synthesized by the amination route. The performance of synthesized exchange resins for the separation and recovery of active Mo(VI) and I(I) isotopes from their aqueous solutions was compared to that of three commercial ion exchange resins, used in the actual production of these radioisotopes in the Radioisotopes Production Facility. The morphology and structural properties of the synthesized copolymers as well as the commercial reference resins were characterized using FT−IR, SEM, TG, and XPS. The results demonstrate that the copolymer was successfully functionalized with amino groups, where trimethylamine produced amination greater than triethylamine. Furthermore, the thermal stability of synthesized anion exchanges was significantly higher than that of commercial beads. The synthesized polymer networks presented excellent radiation stability under applied experimental conditions. Compared to the reference resins, the synthesized co-polymeric beads showed enhanced adsorption capability for MoO4 2− and I− ions from an aqueous solution. Further, the uptake affinity of the networks aminated with trimethylamine for both radioisotopes, in optimal conditions, was greater than that of triethylamine aminated beads. The sorption mechanism was inferred through FT−IR and XPS analysis, and the results clarified that the separation of both radioisotopes was substantially related to the amine functional groups on the resin framework. The spectroscopic analysis illustrated that one molybdenum ion (in the form of MoO4 2−) was subjected to an ion-exchange interaction and two Cl− ions in the amine resin. A similar exchange mechanism was predicted for I− with Cl− ions. Further, the enhanced sorption of Mo(VI) could be additionally attained through coordination interactions with N atoms in the amine groups that have good chelating capability toward metal ions. The reusability performance of the synthesized exchange resins is better than that of the commercial reference resins, where they could be effectively regenerated for up to five cycles. Finally, this study presents a new technique for the separation and recovery of Mo(VI) and I(I) from irradiated low-enriched U-targets by employing highly promising amino-modified polystyrene-divinyl benzene microspheres.

Novel Highly Hydrophilic Resins with Attached Polymer Layers for Liquid Chromatography

The aim of this work was to the obtaining novel mixed-mode stationary phases with increased hydrophilicity and applying them in ion and hydrophilic interaction liquid chromatography. The resins were obtained by the sequential covalent attachment of branched polyethylenimine and polyelectrolytes synthesized from diepoxide and a secondary amine on the surface of epoxidized polystyrene–divinylbenzene. To increase the shielding degree of the polymer substrate, an additional polymerization of glycidol was carried out in the functional layer of the sorbent at an increased pH of the reaction medium. The synthesized phases possessed increased hydrophilicity compared to most resins based on a styrene–divinylbenzene copolymer with covalently attached layers. This was evidenced in the ion chromatography mode by a decrease in the relative retention of polarizable anions, weakly hydrated oxyhalides (up to a change in the elution order of the bromate), and haloacetic acids. In the hydrophilic interaction liquid chromatography mode, an increased hydrophilicity of the phases was confirmed by an increase in the retention factors of polar analytes, as well as by the reversal of the elution order of ascorbic and nicotinic acids as compared to the phases based on polystyrene–divinylbenzene presented in the literature. The low efficiency of the obtained stationary phases in the ion chromatography mode was noted, which is associated with slow mass transfer in the bulk polymer functional layer. The negative impact of the polymer layer on efficiency in hydrophilic interaction liquid chromatography is less pronounced due to the presumably smaller thickness of the part of the functional layer involved in this mode. The proposed method for the synthesis of resins ensures an increase in the efficiency, selectivity, and separation ability of sorbents in the hydrophilic interaction liquid chromatography mode as compared to phases based on a styrene–divinylbenzene copolymer described previously in the literature. The resulting highly hydrophilic resins makes it possible to separate a mixture of 9 nitrogenous bases and nucleosides in 18 min, 6 vitamins in 24 min, and 8 sugars in 11 min. Thus, the method of substrate hydrophilization proposed in this work is promising for improving the chromatographic characteristics of phases in the hydrophilic interaction liquid chromatography mode and can be used to create sorbents with increased selectivity and efficiency.

Fe3O4@PS-DVB microspheres modified with urea functional groups for rapid and green extraction of fluorinated aromatic carboxylic acids from tap and formation water

The present study describes the trace analysis of 23 fluorinated aromatic carboxylic acids based on the dispersive magnetic solid phase extraction (m-SPE) technique coupled with the gas chromatography coupled with mass spectrometry (GC–MS) electron ionization (EI) technique. A commercial hydrophilic-lipophilic balanced (HLB) material polystyrene divinyl benzene having urea functional groups was modified with magnetite nanoparticles and employed as a sorbent for dispersive m-SPE of fluorobenzoic acids (FBAs) from the tap and formation water samples. The extraction occurred due to π- π interaction between the aromatic ring of synthesized sorbent and the aromatic ring of FBAs, the hydrogen bond formation between the urea functional group of the sorbent and carbonyl oxygen, fluorine of the FBAs. As a result, the method was precise, rapid, reproducible, and calibrated with the coefficient of variation (R2) greater than 0.98 for all 23 compounds. The instrument detection limit (IDL) and method detection limit (MDL) were found in the range of 2.60 – 8.25 ng/mL and 0.08 – 0.28 ng/mL respectively. Extraction efficiencies were found in the range of 83.80–100 % for tap water samples and 78.41–98.92 % for formation water samples, respectively, with an enrichment factor of 33.33–66.66 and a maximum RSD of 7.07 %. The recyclability and magnetic properties of the synthesized material were also investigated, resulting in the material being reused for six cycles without impacting its performance; hence, the method offers rapid determination and high throughput analysis of FBAs. In addition, simulation studies were performed using the adsorption location tool of Material Studio, confirming the interaction sites of sorbent with FBAs. AGREE evaluated the analytical greenness of the method, and the score was found to be 0.51.

Proton Self‐Limiting Effect of Solid Acids Boosts Electrochemical Performance of Zinc‐ion Batteries

AbstractAt present, aqueous rechargeable Zn–MnO2 batteries have attracted widespread attention as green potential application for renewable energy storage devices. MnO2 cathode has great potential for application, but its proton reaction results in side reactions of cathode, electrolyte consumption, and dramatic pH value changes, suffering from capacity degradation. To address the issues caused by proton deficit, a proton–limited domain strategy is proposed by integrating solid acids (Sulfonic acid type polystyrene–divinylbenzene, SATP) with proton exchange reactions into MnO2. SATP can act as a new proton source increasing the amount of H+ and reducing the generation of zinc hydroxide sulfate, by–product of proton at the cathode interface, via proton exchange reactions of ‐HSO3– group. As a result, Zn–MnO2/SATP battery delivered with excellent rate performance (218.4 mAh g–1 at 2 A g–1) and high cycling stability (the retained capacity of 115.8 mAh g–1 after 500 cycles at a current density of 1 A g–1. This work provides an innovative strategy for high performance aqueous Zn–MnO2 batteries.

Modified Diglycolamide Resin: Characterization and Potential Application for Rare Earth Element Recovery

Rare earth elements (REEs) are crucial for green energy applications due to their unique properties, but their extraction poses sustainability challenges because the global supply of REEs is concentrated in a few countries, particularly China, which produces 70% of the world’s REEs. To address this, the study investigated TK221, a modified extraction chromatographic resin featuring diglycolamide (DGA) and carbamoyl methyl phosphine oxide (CMPO), as a promising adsorbent for REE recovery. The elemental composition and functional groups of DGA and CMPO on the polystyrene-divinylbenzene (PS-DVB) support of TK221 were confirmed using scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), and X-ray photoelectron spectroscopy (XPS). The adsorption kinetics of neodymium (Nd), yttrium (Y), cerium (Ce), and erbium (Er) followed the pseudo-second-order kinetic model and Langmuir isotherm, indicating monolayer chemisorption. Furthermore, iron (Fe) adsorption reached apparent equilibrium after 360 min, with consistent Fe adsorption observed at both 360 min and 1440 min. The inclusion of Fe in the study is due to its common presence as an impurity in most REE leachate solutions. The Fe adsorption isotherm results are better fitted with the Langmuir isotherm, implying chemisorption. Maximum adsorption capacities (qmax) of the resin were determined as follows: Nd (45.3 mg/g), Ce (43.1 mg/g), Er (35.1 mg/g), Y (15.6 mg/g), and Fe (12.3 mg/g). ATR-FTIR analysis after adsorption suggested that both C=O and P=O bands shifted from 1679 cm−1 to 1618 cm−1 and 1107 cm−1 to 1142 cm−1 for Y, and from 1679 cm−1 to 1607 cm−1 and 1107 cm−1 to 1135 cm−1 for Ce, implying possible coordination with REEs. These results suggest that TK221 has a huge potential as an alternative adsorbent for REE recovery, thus contributing to sustainable REE supply diversification.

Microextraction by packed sorbent of N-nitrosamines from Losartan tablets using a high-throughput robot platform followed by liquid chromatography-tandem mass spectrometry.

The development of a fast, cost-effective, and efficient microextraction by packed sorbent setup was achieved by combining affordable laboratory-repackable devices of microextraction with a high-throughput cartesian robot. This setup was evaluated for the development of an analytical method to determine N-nitrosamines in losartan tablets. N-nitrosamines pose a significant concern in the pharmaceutical market due to their carcinogenic risk, necessitating their control and quantification in pharmaceutical products. The parameters influencing the performance of this sample preparation for N-nitrosamines were investigated through both univariate and multivariate experiments. Microextractions were performed using just 5.0mg of carboxylic acid-modified polystyrene divinylbenzene copolymer as the extraction phase. Under the optimized conditions, the automated setup enabled the simultaneous treatment of six samples in less than 20 min, providing reliable analytical confidence for the proposed application. The analytical performance of the automated high-throughput microextraction by the packed sorbent method was evaluated using a matrix-matching calibration. Quantification was performed using ultra-high-performance liquid chromatography-tandem mass spectrometry with chemical ionization at atmospheric pressure. The method exhibited limits of detection as low as 50ng/g, good linearity, and satisfactory intra-day (1.38-18.76) and inter-day (2.66-20.08) precision. Additionally, the method showed accuracy ranging from 80% to 136% for these impurities in pharmaceutical formulations.

Past to Future: Application of Gel Permeation Chromatography from Petroleomics and Metallopetroleomics to New Energies Applications: A Minireview

In the field of petroleomics and metallopetroleomics, the gel permeation chromatography (GPC) technique coupled with high-resolution detection technologies has made significant contributions as an analytical and preparative tool for over five decades. This bibliographic minireview highlights the study of the supramolecular and structural behavior of heavy crude oil and its fractions, as well as their reactivity to various processes by use of GPC. The preferred mobile phase is tetrahydrofuran (THF), whereas the stationary phase is polystyrene–divinylbenzene copolymer to avoid compound retention in the column. Other techniques such as HPTLC, RPLC, and NPHPLC have been used to provide multidimensional separations complementary to GPC. The high molecular weight (HMW) fraction, due to its greater polarity, reactivity to polymerization, and resistance to hydrodemetallization processes, has been the focus of interest for years. GPC coupled with high-resolution techniques has proven to be reliable for the detection of organic and inorganic species in bio-oils, making it a valuable tool for researchers and industry professionals in the context of feedstocks changes and new energy production.

Resins Based on Polystyrene–Divinylbenzene with Attached Hydrophilized Polyethyleneimine for Ion and Hydrophilic Interaction Liquid Chromatography

Resins Based on Polystyrene–Divinylbenzene with Attached Hydrophilized Polyethyleneimine for Ion and Hydrophilic Interaction Liquid Chromatography

Resins Based on Polystyrene–Divinylbenzene with Attached Hydrophilized Polyethyleneimine for Ion and Hydrophilic Interaction Liquid Chromatography

To expand the field of application of anion exchangers based on a copolymer of styrene and divinylbenzene with attached polyethyleneimine, quaternized with glycidol, the following conditions for their synthesis were varied: the amount of the added glycidol, temperature, and duration of synthesis. The influence of these factors on the capacity, selectivity, and efficiency of the resins in the mode of suppressed ion chromatography was studied; in addition, the stationary phases were studied in the mode of hydrophilic interaction liquid chromatography using the Tanaka test. It was shown that the synthesis conditions under study ensure the control of the capacity and selectivity of anion exchangers, while their hydrophilicity changes insignificantly. The behavior of oxoanions on covalently attached resins in the ion chromatography mode was studied for the first time, and the applicability of phases with quaternized polyethyleneimine in the hydrophilic interaction liquid chromatography mode to the separation of sugars, amino acids, water-soluble vitamins, nucleosides, and nitrogenous bases was demonstrated for the first time.

Novel Mixed-Mode Adsorbents for HPLC Based on Different Substrates Modified with Eremomycin

New adsorbents based on silica and polystyrene–divinylbenzene (PS–DVB) for hydrophilic interaction liquid chromatography (HILIC) with eremomycin in functional layers were obtained. The chromatographic properties of the new adsorbents were assessed using the Tanaka test for hydrophilic stationary phases and by studying the retention of substances of various classes in HILIC, chiral, and reversed-phase chromatography modes. It was shown that the use of eremomycin to create functional layers leads to an increase in the hydrophilicity of the adsorbents on different types of substrates and ensures the shielding of their charge. Eleven nitrogenous bases, nucleosides with an efficiency of up to 25 000 tp/m, or seven vitamins with an efficiency of up to 40 000 tp/m can be separated on a modified sorbent based on aminopropyl silica, and three different HPLC modes can be implemented on the sorbent with eremomycin based on PS–DVB.

Extractive adsorption of 1,3-propanediol on a novel polystyrene macroporous resin enclosing medium and long-chain alcohols as extractant

Extractive adsorption is an integrated separation method employing a novel resin with both particle and liquid characteristics in terms of adsorption and extraction. In this study, the novel extractive adsorption polystyrene-divinylbenzene (PS-DVB) macroporous resin was synthesized by suspension polymerization, in which n-octanol (OL-PS-DVB) or mixed alcohols of n-octanol, undecyl alcohol, and tetradecyl alcohol (MA-PS-DVB) were added as porogen and enclosed in the resin skeleton after the reaction. The characterization of the two novel resins of OL-PS-DVB and MA-PS-DVB showed that they have large specific surface areas of 48.7 and 17.4 m2/g, respectively. Additionally, the two synthesized resins have much higher static adsorption capacities of 1,3-propanediol (511 and 473 mg/g) and dynamic adsorption capacities (312 and 267 mg/g) than traditional resins, because extractants enclosed in the resin can increase the adsorption capacity. Through Langmuir equation, the theoretical static maximum adsorption capacity of the mixed alcohols resin is 515 mg/g at 298 K and Gibbs free energy change of adsorption was -3781 J/mol, indicating that the adsorption process was spontaneous. In addition, the sorbent concentration effect in the resin was generated at high 1,3-propanediol (1,3-PDO) concentrations. The fitting of the Flocculation model can reveal that there is a possible relation between adsorption and flocculation. Compared to OL-PS-DVB, MA-PS-DVB showed better performance in the recovery yield of 1,3-PDO and other byproducts, the removal rates of the inorganic salt and protein, and the efficiency of recycled resin. For MA-PS-DVB, the recovery of 1,3-PDO, butyrate acid, acetic acid, and residual glycerol was 97.1%, 94.7%, 93.3%, and 90.3%, respectively. Simultaneously, the resin of MA-PS-DVB could remove 93.8% of inorganic salts and 90.9% of proteins in the concentrated fermentation broth. The two synthesized resins of OL-PS-DVB and MA-PS-DVB still had 90% or 92% of capacity for extractive adsorption of 1,3-propanediol after 10 times of recycling, which exhibited potential application in the separation of 1,3-propanediol from fermentation broth.

Broadband reflection induced by chiral dopant-loaded mesoporous polystyrene-divinylbenzene microspheres via diffusion in polymer stabilised cholesteric liquid crystals

ABSTRACT A new method to construct polymer stabilised cholesteric liquid crystal (PSCLC) films with broadband reflection in the near infrared region (NIR) has been proposed which utilises the chiral dopant-loaded mesoporous polystyrene-divinylbenzene (PS-DVB) microspheres. The diffusion time, UV intensity and temperature during polymerisation were investigated to control the diffusion of chiral dopant and the polymerisation process which could affect the non-uniform pitch distribution and thus the reflection bandwidth. The optimised reflection bandwidth was broadened from 300 nm to 860 nm. Potential application fields of broadband reflective films include smart windows for the control of the solar-light irradiation, and military infrared shielding devices.

Synthesis of Hyper-cross-linked Nonpolar Polystyrene Divinylbenzene Resins by Pendent Vinyl Groups and Application to the Decolorization of Cane Molasses.

Cane molasses is a by-product of sugar industry. It is widely used in fermentation field, but pigment compounds affect its further application. In this study, nonpolar hyper-cross-linked adsorption resins (HCARs) were synthesized by pendent vinyl groups cross-linking reaction, and were applied to decolorization of molasses. The correlation between the structure and the decolorization performance of HCARs was studied, and the results showed that the Brunauer-Emmett-Teller (BET) surface area and the pore volume of the resin significantly increased to 574.4 m2·g-1 and 1.40 cm3·g-1 after the Friedel-Crafts alkylation reaction with a catalyst dosage of 2.25% at 343K for 7h. Furthermore, the decolorization rate of molasses by the HCAR was 74%, and recycle decolorization performance of the resin was stable. The adsorption kinetics results showed that the pseudo-second-order dynamic model could more realistically reflect the decolorization mechanism of molasses on HCARs, and liquid film diffusion is the main rate-limiting step. The results of fixed-bed experiments show that D-ST-DVB resin has a good decolorization effect and recycling ability. Therefore, it is a feasible strategy for the decolorization of molasses with nonpolar HCAR.

Microspherical polystyrene-divinylbenzene particles hybridized with eremomycin stabilized gold nanoparticles as a stationary phase for chiral liquid chromatography

A novel enantioselective adsorbent was obtained by hybridization of microspherical polystyrene-divinylbenzene (PS-DVB) macroporous particles with eremomycin-stabilized gold nanoparticles (GNPs). Macrocyclic antibiotic eremomycin was used as a stabilization agent to obtain GNPs which were then characterized by transmission electron microscope. The average diameter of obtained nanoparticles is about 16.6 nm. Eremomycin-stabilized nanoparticles were successfully embedded into the porous polymer structure with a resulting chiral selector content of 37.5 pmol/g. The obtained PS-DVB composite containing GNPs with immobilized eremomycin was studied by scanning electron microscopy and diffuse reflectance spectroscopy. The values of the specific surface area (500 m2/g) and porosity of the adsorbent (0.39 cm3/g) are measured using nitrogen adsorption at low temperatures. The obtained composite material was used as a chiral stationary phase of liquid chromatography. A good separation enantio-selectivity to amino acids, their derivatives and beta-blockers under RPC (reversed-phase) and HILIC (Hidrophilic Interaction Liquid Chromatography) mode is demonstrated. The results obtained revealed that the prepared Eremo@GNP@PS-DVB composite is promising for use as a stationary phase in HPLC.

Investigation of synergetic effect of adsorption and photocatalysis for the removal of tetracycline by BiFeO3 immobilized on copolymer seeds

The utilization of powdered photocatalysts can cause problems such as agglomeration and difficulty in separation in conventional applications. In this work, deposition of photocatalyst particles on a co-polymeric network was suggested to solve this issue. For this purpose, ferrite type perovskite BiFeO3 particles were immobilized on the sulphonated polystyrene-divinyl benzene seeds via a facile impregnation process and the heterostructured catalyst (BFO@co-STR/DVB) exhibited boosted removal performance towards tetracycline antibiotic. The co-polymer itself showed attractive adsorption (93% removal) towards tetracycline due to the robust π–π stacking or hydrophobic relationship. The photocatalytic performance of optimal BFO@co-STR/DVB catalyst had the greatest value of apparent rate constant (0.037 min-1), which was 6.16 times higher than that for bare BiFeO3 (0.006 min-1). Moreover, the heterostructured photocatalyst displayed the highest catalytic efficiency as 98.5% which was mainly assigned to the synergetic effect of adsorption and photocatalysis. Therefore, detailed adsorption mechanism was examined by applying three kinetic models and the pseudo-second order model (qe=88.9 mg/g; R2=0.993) was fitted well describing well the adsorption. The impact of perovskite amount on the polymer structure was also investigated. Apart from tetracycline molecule, the photocatalytic activity of the heterostructured catalyst with respect to different pharmaceutical (isoniazid) was also investigated and the adsorptive removal of isoniazid over the co-STR/DVB polymer was calculated as 80.0% while it significantly increased to 98.2% in the BFO@co-STR/DVB photocatalytic system. This study demonstrated the effective utilization of the perovskite deposited co-polymeric network in the field of “photocatalysis”.

Controllable polyvinylpyrrolidone modified Polystyrene divinylbenzene for efficient adsorption of bilirubin and improvement of hemocompatibility

Bilirubin, a dangerous toxin may lead to serious brain injury, can be widely removed by hemoperfusion. However, the hemoperfusion adsorbents with higher removal ability, excellent hemocompatibility and biocompatibility still need to be explored. In this work, a novel functionalized polyvinylpyrrolidone (PVP) was synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization. Then PVP-modified polystyrene-divinylbenzene (PS-DVB-PVP) microspheres were prepared by a one-pot restore-click method. The results showed that the adsorption capacity and rate of microspheres for bilirubin were increased after modification with PVP. In the hemocompatibility and biocompatibility test, the modified microspheres demonstrated higher resistance to human serum albumin (HSA) and excellent hemolysis rate. In order to study the role of PVP in the bilirubin-adsorption process, isotherms were fitted by Langmuir model and Freundlich model, while kinetics data were fitted by pseudo-second-order model and intraparticle diffusion model. In addition, the modified microspheres showed no difference with unmodified microspheres in the coagulation test and exhibited no cytotoxicity to L929 cells. These results showed that our modified microspheres have both excellent hemocompatibility and outstanding biocompatibility, which will not cause hemolysis and coagulation. All these results made them possible to become a new adsorbent for efficient removing bilirubin in hemoperfusion.

A chemically functionalized hydroxyacetamide anchored polymeric adsorbent for the selective separation of zirconium from acidic aqueous solutions

In the present study, a chelating hydroxyacetamide anchored resin (PS-HOAc), prepared by the chemical modification of a commercially available chloromethylated polystyrene-divinylbenzene (PS-DVB) resin, was developed for the removal of Zr(IV) from acidic aqueous solutions. FT-IR, thermogravimetry, and SEM-EDX studies revealed the chemical linking of hydroxyacetamide group on the polystyrene network. The synthesized PS-HOAc resin has manifested to be highly selective for the adsorption of Zr(IV) as compared to Nd(III) and U(VI) in 0.1 M to 4 M nitric acid feed solutions. The adsorption behavior of Pu(IV) was comparable with Zr(IV). The apparent adsorption capacity for the adsorption of Zr(IV) derived by the Langmuir adsorption isotherm model was 92.6 mg.g−1, which is comparable with the equilibrium adsorption capacity derived from the Pseudo-first-order (Lagergren) model (93.6 mg.g−1). Selective separation of Zr(IV) in the presence of U(VI) and Nd(III) was also established by column studies experiments.

Single enrichment systems possibly underestimate both exposures and biological effects of organic pollutants from drinking water

Comprehensive enrichment of contaminants in drinking water is an essential step for accurately determining exposure levels of contaminants and testing their biological effects. Traditional methods using a single absorbent for enriching contaminants in water might not be adequate for complicated matrices with different physical-chemical profiles. To examine this hypothesis, we used an integrated enrichment system that had three sequential stages-XAD-2 resin, poly (styrene–divinylbenzene) and activated charcoal to capture organic pollutants and disinfection by-products (DBPs) from drinking water in Shanghai. Un-adsorbed Organic Compounds in Eluates (UOCEs) named UOCEs-A, -B, and-C following each adsorption stage were determined by gas chromatography-mass spectrometry to evaluate adsorption efficiency of the enrichment system. Meanwhile, biological effects such as cytotoxicity, effects on reactive oxygen species (ROS) generation and glutathione (GSH) depletion were determined in human LO2 cells to identify potential adverse effects on exposure to low dose contaminants. We found that poly-styrene–divinylbenzene (PS-DVB) and activated charcoal (AC) could still partly collect UOCEs-A and-B that the upper adsorption column incompletely captured, and that potential carcinogens like 2-naphthamine were present in all eluates. UOCEs-A at (1–4000), UOCEs-B at (1000–4000), and UOCEs-C at (2400–4000) folds of the actual concentrations had significant cytotoxicity to LO2 cells. Additionally, ROS and GSH change in cells treated with UOCEs indicated the potential for long-term effects of exposure to some mixtures of contaminants such as DBPs at low doses. These results suggested that an enriching system with a single adsorbent would underestimate the exposure level of pollutants and the biological effects of organic pollutants from drinking water. Effective methods for pollutants’ enrichment and capture of drinking water should be given priority in future studies on accurate evaluation of biological effects exposed to mixed pollutants via drinking water.

Design of a sustainable process for enzymatic production of ethylene glycol diesters via hydroesterification of used soybean cooking oil

The aim of this study was to produce diol diesters, an important class of synthetic esters with lubricant properties, via enzymatic hydroesterification of used soybean cooking oil (USCO). Initially, free fatty acids (FFAs) were produced through hydrolysis of USCO catalyzed using powder lipase extract from Candida rugosa. Afterwards, different diols and FFAs were esterified using Eversa® Transform 2.0, a low-cost liquid lipase derived from Thermomyces lanuginosus, immobilized via interfacial activation on polystyrene-divinylbenzene (PSty-DVB) beads as biocatalyst. The immobilization improved its catalytic activity and the best performance was observed using ethylene glycol (EG). Thus, it was selected for further ester production optimization. The effect of relevant factors on EG diesters production was assessed through a central composite rotatable design (CCRD). As a result, full OH conversion was achieved at 65 °C using EG:FFA molar ratio of 1:3% and 18% of mass of heterogeneous biocatalyst per mass of starting materials after 40 min of reaction. Maximum OH conversion was only 32.5% using soluble lipase under such conditions. The prepared biocatalyst retained ≈ 37% of its original activity after seven successive esterification batches. Viscosity index (166.2 ± 18.2), pour point (–9 ± 2 °C) and density at 20 °C (0.8794) values of the produced EG diesters were similar to other EG esters produced from soybean oil in literature and commercial synthetic neopolyol esters.