Commercial Sorbents Research Articles

Mechanistic investigations into the removal of Hg0 over Pt-based sorbents by warm syngas cleanup

Commercial sorbents for Hg0 removal from syngas operate at low temperatures (<120 ºC), which impacts the thermal efficiency of integrated gasification and chemical production processes. For the first time, supported Pt-based sorbents with different supports, viz., Pt/SBA-15, Pt/S-40, Pt/ZrO2, Pt/CeO2, and Pt/TiO2 are synthesized for high-temperature (≥200 ºC) Hg0 removal. Pt/SBA-15 shows the highest cumulative Hg0 removal efficiency (>99%) at 270 ºC in N2, which is retained for much higher durations (>20h) compared to the best-reported Pd-based and metal oxide sorbents. Besides amalgam formation, Hg0 removal on Pt/ZrO2 and Pt/CeO2 occurs via oxidation at high temperatures (> 270 ºC), which explains the reduced negative effect of high temperature over these sorbents. In contrast to other supports, the removal efficiency over Pt/SBA-15 is above 99% even in the presence of H2, H2O, and CO2, and is attributed to the hydrophobic mesoporous silica support. DRIFTS studies indicate CO adsorption on the active Pt sites over all sorbents. Based on the inferences obtained, a kinetic model is developed and integrated into a reactor-scale model which effectively simulates the spatio-temporal features of Hg0 sorption over Pt/SBA-15.

Evaluation of Jacalin lectin sorbents for the extraction of the human chorionic gonadotropin glycoforms prior to analysis by nano liquid chromatography-high resolution mass spectrometry

Human chorionic gonadotropin (hCG) is a dimeric, highly glycosylated hormone with a total of 4 N- and 4 O-glycosylation sites in its two subunits, hCGα and hCGβ. Recently, we developed a novel nano liquid chromatography coupled to high resolution mass spectrometry (nanoLC-HRMS) method for the analysis and thus the detection of the intact glycoforms of hCG. Here, a sorbent functionalized with the Jacalin lectin was evaluated in solid-phase extraction (SPE) for its potential to fractionate the hCG glycoforms prior to their nanoLC-HRMS analysis at the intact level, which may facilitate the detection of low-abundance glycoforms and may lead to a more detailed characterization of the hormone glycosylation. A commercial sorbent based on Jacalin immobilized on Sepharose and having a lectin density of 4.5mg per ml of gel was selected to carry out SPE and its capacity was estimated to be of some tens of μg of hCG per ml of lectin sorbent. Next, the SPE protocol was modified to improve the extraction recoveries. Especially, it was noticed that an extensive pre-conditioning procedure prior to the first use of a cartridge was necessary to remove the residual non-grafted lectins. Indeed, if on-grafted lectins are not eliminated, they may bind a part of hCG glycoformes preventing they retention by the sorbent, leading to low extraction recoveries (around 10%). With the extensive pre-conditioning procedure, the average extraction recoveries for both hCGα and hCGβ glycoforms were about 50%, with either recombinant or urinary hCG. Qualitatively, the fractionation of hCG glycoforms between the washing and elution fractions was achieved with the urinary hCG sample by determining the number of glycoforms detected in each fraction. It appears that 12 hCGα glycoforms have a low affinity (detected only in the washing fraction), 1 a low-medium affinity (detected in washing and elution 1 fractions), 16 a medium affinity (detected in washing, elution 1 and 2 fractions), and 12 a high affinity (detected only in elution 1 and 2 fractions). For the hCGβ glycoforms, similarly, 3 have a low affinity and 12 a low-medium affinity. Additionally, the 3 hCGβ glycoforms were detected better. A different behavior was observed with the recombinant hCG sample, which indicates glycosylation differences between the two hCG samples. This shows the potential of lectin-based affinity fractionation before nanoLC-HRMS analysis to better characterize the glycosylation state of hCG at the intact level.

Transformation of Graphite Recovered from Batteries into Functionalized Graphene-Based Sorbents and Application to Gas Desulfurization.

The recycling and recovery of value-added secondary raw materials such as spent Zn/C batteries is crucial to reduce the environmental impact of wastes and to achieve cost-effective and sustainable processing technologies. The aim of this work is to fabricate reduced graphene oxide (rGO)-based sorbents with a desulfurization capability using recycled graphite from spent Zn/C batteries as raw material. Recycled graphite was obtained from a black mass recovered from the dismantling of spent batteries by a hydrometallurgical process. Graphene oxide (GO) obtained by the Tour's method was comparable to that obtained from pure graphite. rGO-based sorbents were prepared by doping obtained GO with NiO and ZnO precursors by a hydrothermal route with a final annealing step. Recycled graphite along with the obtained GO, intermediate (rGO-NiO-ZnO) and final composites (rGO-NiO-ZnO-400) were characterized by Wavelength Dispersive X-ray Fluorescence (WDXRF) and X-ray diffraction (XRD) that corroborated the removal of metal impurities from the starting material as well as the presence of NiO- and ZnO-doped reduced graphene oxide. The performance of the prepared composites was evaluated by sulfidation tests under different conditions. The results revealed that the proposed rGO-NiO-ZnO composite present a desulfurization capability similar to that of commercial sorbents which constitutes a competitive alternative to syngas cleaning.

Hydrated carboxylate ionic liquids as chemical CO2 sorbents of high capacity and moderate enthalpy of absorption

Tetralkylphosphonium carboxylate ionic liquids are herein presented as efficient carbon dioxide chemisorbents in the presence of water. The ionic liquids tetrabutylphosphonium formate and acetate, tributylmethylphosphonium formate and a series of triethylalkylphosphonium formates and acetates, have been prepared by various synthetic procedures either from hydroxide or methylcarbonate precursors, or via multiple steps starting from the parent triethylphosphine. Their physicochemical properties, namely melting or glass transition temperatures, thermal decomposition behaviour, densities and viscosities have been determined. As dry substances, they are viscous liquids or low-melting solids, whereas they show little tendency to solidify in their hydrated forms. They were used mostly as monohydrates in CO2 solubility measurements, exhibiting highest capacities (3 mol L−1, i.e. ≈ 0.9 molCO2 molIL−1, at 5 bar, 25 °C) at equimolar H2O/ionic liquid ratios, approaching those of commercial aqueous amine sorbents. Carbon dioxide chemisorption into hydrogencarbonate takes place, as demonstrated by infrared spectroscopy with isotopic labelling. CO2 absorption isotherms were recorded at various temperatures and the data used to estimate the heat of absorption according to three different thermodynamic models. Enthalpies of CO2 absorption depended heavily on the model used. Rationalisation of this was done on the grounds of the expected relevance of physical and chemical sorption processes. Average heats of CO2 absorption lie between −40 and −45 kJ mol−1, in accordance with mild chemical absorption albeit significantly lower than those for typical chemical sorbents such as amines. This reinforces the feasibility of hydrated carboxylate ionic liquids for CO2 capture technologies of low regeneration energies.

Post-Removal of Phosphorus from Biologically Treated Wastewater and Recovering It as Fertilizer: Pilot-Scale Attempt—Project PhoReSe

The major issue of raw materials’ depletion, and more specifically, of phosphorous (an important fertilizer) has currently become an emergent aspect due to expected depletion problems needing immediate handling. This was the reason for the implementation of the PhoReSe project that aimed to remove and recover phosphorus from the secondary (biologically treated) effluent of a municipal wastewater (biological) treatment plant (WWTP “AINEIA”, located near Thessaloniki, N. Greece), treating the wastewaters of the nearby touristic area. Regarding the phosphorous supplementary removal and recovery treatment options, two methods were examined, initially at the laboratory scale (batch experiments), i.e., (1) the adsorption of phosphorous, and (2) the chemical precipitation of phosphorus. Both methods were further applied at the pilot scale by initially performing the adsorption of phosphorous onto the AquAsZero commercial sorbent, which is a mixed manganese iron oxy-hydroxide, followed by the chemical precipitation of phosphorous implemented after the desorption process of the previously saturated adsorbent. The final precipitate of this procedure was examined as an alternative/supplementary fertilizer, this way returning phosphorus into the natural cycle. These experiments, as applied successfully in at the pilot scale, set the basis for larger-scale relevant applications for similar WWTP facilities.

Use of Commercial Mixed-Mode Stationary Phases and Sorbents in the High-Performance Liquid Chromatography Analysis and Solid-Phase Extraction of Ionized and Hydrophilic Bioactive Compounds.

Mixed-mode high-performance liquid chromatography (HPLC) is increasingly used for the analysis of ionic and highly hydrophilic drugs, which are difficult to separate by conventional single-mode HPLC. In the former case, chromatographic separation is achieved using one of the several commercially available mixed-mode stationary phases, typically combinations of reversed and ion-exchange phases. Moreover, mixed-mode stationary phases can be used as solid-phase extraction (SPE) sorbents. This review focuses on the recent applications of mixed-mode stationary phases in the chromatographic analysis of bioactive compounds, such as drugs, herbicides, and pesticides. Specifically, we briefly summarize HPLC methods utilizing mixed-mode stationary phases and SPE pretreatment procedures utilizing mixed-mode sorbents developed in the last decade, thus providing a reference work for overcoming the difficulties in analyzing ionized or hydrophilic drugs by conventional reversed-phase chromatography.

Developing Green Sorbents Derived from Natural Materials for Microextraction and Determination of Emerging Contaminants

Developing Green Sorbents Derived from Natural Materials for Microextraction and Determination of Emerging Contaminants

New Approach for Sulfidation Process in Packed Bed with Hi-Fuel A310 Sorbent—Thermodynamical Studies

This paper presents tests related to the reactivity of commercial Hi-Fuel sorbent toward H2S (H2S/N2 mixture) in a packed bed at 300 °C. The sorbent used for breakthrough test was characterized before and after test by ESEM-EDX, FTIR-ATR, Raman, and elemental analyses. Testing reveals that the commercial sorbent contains two compounds reacting with H2S: ZnO and ZnCO3. According to thermodynamical studies, the reactivity of ZnCO3 at 300 °C is privileged (KR = 9.5 × 108) than ZnO (KR = 6.6× 106). In addition, the reaction of H2S with ZnCO3 induces a volume decrease, which promotes the movement of gas through the newly formed layer. The properties of this sorbent thus hold a good potential for the desulfurization process of gases polluted with H2S. We observed that the maximum sulfidation rate was reached on the surface of the sorbent and showed a maximum conversion of 27%.

Emulsion synthetic route of hierarchically porous zeolite-geopolymer composites for Sr2+ decontamination in fixed bed process

The decontamination of wastewater is an important issue for the nuclear industry. The removal of Sr2+, one of the most problematic radioelements, requires hierarchical materials suitable for fixed-bed processes. This article describes a patented emulsion-templating route for the synthesis of Linde Type A (LTA) zeolite-geopolymer composites with a multiscale porosity. By dispersing zeolite particles in an emulsion oil-in-water containing precursors of geopolymer, LTA zeolite–geopolymer composites can be obtained after curing and eliminating the oil phase. The zeolite particles alter the macroporous structure of the materials (replicating the oil droplets) as well as the size of the mesopores of the geopolymer binder. Moreover, zeolite contents higher than 30 wt% induce a crumbling of the material structure. The presence of LTA zeolite particles increases the selectivity of the composites for Sr2+ in very saline media, while the porous network of the material ensures rapid adsorption. The optimal composite prepared here outperformed a commercial sorbent for the Sr2+ decontamination of a saline wastewater through a packed column.

Selective recovery of boron, cobalt, gallium and germanium from seawater solar saltworks brines using N-methylglucamine sorbents: Column operation performance

The European Union (EU) identified a list of Critical Raw Materials (CRMs) crucial for its economy, aiming to find alternative sources. Seawater is a promising option as it contains almost all elements, although most at low concentrations. However, to the present, the CRMs' recovery from seawater is technically and economically unfeasible. Other alternatives to implement sea mining might be preferred, such as reverse osmosis brines or saltworks bitterns (after sodium chloride crystallisation). The CRMs' extraction in a selective way can be achieved using highly selective recovery processes, such as chelating sorbents. This study focuses on extracting Trace Elements (TEs) from solar saltworks brines, including boron, cobalt, gallium and germanium, using commercial N-methylglucamine sorbents (S108, CRB03, CRB05). The application of these sorbents has shown potential for boron recovery, but their selectivity for cobalt, gallium, and germanium requires further investigation. This research aims to assess these sorbents' kinetics and column mode performance for TEs recovery from synthetic bitterns. Boron and germanium were rapidly sorbed, reaching equilibrium (>90 %) within 1 h, except for S108, which took 2 h. In column mode, 20–25 pore volumes of bittern were treated to remove boron and germanium, but competition from other elements reduced treatment capacity. An acidic elution (1 M hydrochloric acid) allowed to elute them (>90 %), reaching concentration factors for germanium and boron of 35 and 11, respectively, while cobalt and gallium had less affinity for the sorbents. In addition, the experiments performed were fitted by a mass transfer model to determine the equilibrium constants and selectivities. Therefore, bittern mining has been proven as a secondary/alternative source to obtain CRMs, which can lead the EU to a position in which its dependence on other countries to obtain these raw materials would be decreased.

Sorption-enhanced Fischer-Tropsch synthesis – Effect of water removal

The Sorption-Enhanced Fischer-Tropsch synthesis (SEFTS), with water removal by means of a solid sorbent, has been demonstrated for the first time experimentally. Commercial water sorbents (Zeolites type 13X and 4 A) were thoroughly characterized to determine water sorption capacity at relevant temperatures (100–250°C) as well as multicycle stability after 100 cycles at 210°C. The adsorption capacity of both zeolties decreased with increasing temperature. The adsorption capacity of 4 A remained almost constant after 100 adsorption/desorption cycles, while 13X lost almost 50% of its capacity. Post characterization of the 13X sample showed distorted crystallinity after 100 cycles which explains the drop in stability. The SEFTS experiments were performed as a cyclic operation, first FT reaction and then water sorbent regeneration, at 210 °C and 5 bar. The system with zeolites showed 10% higher CO conversion after 65 hours on stream compared to the system without any sorbents. The selectivities to C5+ was higher for the system with sorbents compared to the system without zeolites. A much steeper deactivation curve was also observed for the system without zeolites at steady state conditions. This might be due to the fact that zeolites adsorbs the water and remove it from the catalyst active centers, thus increase catalyst stability by preventing the catalyst re-oxidation. Overall, this work opens an opportunity for enhancing the catalyst activity in FTS by in situ water sorption.

A chitin-based magnetic hyper-cross-linked polymer for highly efficient enrichment of neonicotinoids in lemon juice and tomatoes

A chitin-based magnetic hyper-cross-linked polymer (labeled as Ch-MHCP) has been successfully synthesized and utilized for highly-effective solid-phase extraction of neonicotinoid insecticides (NEOs). The extraction capability of Ch-MHCP for four common NEOs is higher than that of four commercial sorbents including octadecyl-silane C18, oasis hydrophilic/lipophilic balanced sorbent, oasis mixed anion sorbent and poly-phenylacetic mixed anion sorbent. The large number of hydroxyl and amide groups as well as benzene rings in Ch-MHCP allow the H-bond and π-π* interaction to be the principal adsorption mechanism of Ch-MHCP for NEOs. Besides, polar interaction was also involved in the adsorption process. In combination of Ch-MHCP based extraction technique with high-performance liquid chromatography, a novel analytical method for sensitive detection of NEOs in lemon juice and tomatoes has been established. At optimal conditions, wide linear ranges were obtained to be 0.20–100 ng mL−1 for lemon juice and 0.80–1000 ng g−1 for tomatoes. The detection limits were 0.06–0.12 ng mL−1 for lemon juice and 0.24–0.60 ng g−1 for tomatoes. This work not only provides a powerful tool for simultaneously detecting four NEOs in lemon juice and tomatoes, but also offers a new insight into the preparation of bio-based magnetic sorbents for adsorption/removal of pollutants.

Advanced nanofibrous sorbents for the extraction of pollutants from river water and protein-containing matrices

The extraction efficiencies of thirty types of fibers produced by meltblown, alternating current electrospinning, and meltblown-co-electrospinning technologies were tested as advanced sorbents for on-line solid-phase extraction in a high-performance liquid chromatography system have been tested and compared with a commercial C18 sorbent. The properties of each fiber, which were often depended on the production process, and their applicability were demonstrated with the extraction of the model analytes nitrophenols and chlorophenols from various matrices including river water and to purify complex matrix human serum and bovine serum albumin from macromolecular ballast. Polycaprolactone fibers outperformed other polymers and were selected for subsequent modifications including (i) incorporation of hybrid carbon nanoparticles, i.e., graphene, activated carbon, and carbon black into the polymer prior to fiber fabrication, and (ii) surface modification by dip coating with polyhydroxy modifiers including graphene oxide, tannin, dopamine, hesperidin, and heparin. These novel fibrous sorbents were comparable to commercial C18 sorbent and provided excellent analyte recoveries of 70–112% even from the protein-containing matrices.

Adsorption mechanisms and regeneration heat analysis of a solid amine sorbent during CO2 capture in wet flue gas

H2O is an important fraction in industrial flue gas, and its impact on CO2 adsorption and energy consumption during CO2 capture in wet flue gas are important concerns by both industry and academia. This study investigated the adsorption mechanisms of CO2 and H2O and the corresponding regeneration heats of a commercial sorbent experimentally. By analyzing the adsorption isotherms of CO2 and H2O, it is found that the adsorption of CO2 and H2O on the sorbent is mainly chemisorption and multilayer physisorption respectively, which are also reflected by the measured adsorption heats. To evaluate the regeneration heat more accurately, a modified model was proposed, which considered the sensible heat required to heat the adsorbed H2O from adsorption to desorption temperature. By analyzing the influencing factors of regeneration heat based on the modified model, the heat due to the desorption of the co-adsorbed H2O in wet flue gas contributes the most. Further, energy-saving strategies e.g. increasing the adsorption temperature, reducing the H2O content of flue gases and using steam as the stripping gas during desorption are provided. In addition, increasing the CO2 working capacity and reducing the sorbent's affinity to H2O are two main improvement directions of the current solid amine sorbents.

Evaluation of various commercial lipid removal sorbents for the detection of 18 neonicotinoid insecticides and their metabolites in meat by liquid chromatography tandem mass spectrometry

AbstractA highly accurate and precise method for the simultaneous detection of 18 neonicotinoids and their metabolites in meat was developed using liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). To improve the pretreatment step of the method, five different commercially available clean-up materials (including C18+PSA (primary secondary amine), Z-Sep (with Discover DSC-C18), EMR-Lipid, SHIMSEN QuEChERS, and Clean-up LPAS) were studied in the treatment of three meat matrices: pork, duck and yellow croaker. Based on the recovery data, we found that among the five purification materials, SHIMSEN QuEChERS was slightly more effective than the others for 18 neonicotinoids. Therefore, SHIMSEN QuEChERS was used as the purification sorbent, and the extraction solvents, extraction methods and chromatographic and mass spectrometric conditions were optimized. A matrix-matched calibration method was applied for quantification. In three different meat matrixes (pork, duck, and yellow croaker), all the target compounds showed good linearity, both with values of r2 &gt; 0.995. The average recovery of all neonicotinoids ranges from 63.4 to 114.2% (pork), 63.0–113.2% (duck), and 63.9–110.5% (yellow croaker). Relative standard deviations were all &lt;15% for intraday and interday precision. The values of limit of detection (LOD) and limit of quantification (LOQ) were, respectively, ranging from 0.04 to 1.0 μg kg−1 and 0.10 to 2.0 μg kg−1. Compared with previous reports, this method has advantage in LOQs, indicating that it it may be a preferred choice for the detection of neonicotinoid pesticides in meat samples.

Synthesised and modified zeolite for effective management of beryllium contaminants in aqueous media under different conditions

The effective management of beryllium (Be) in solution is not well established. In this study, zeolite was synthesised from coal fly ash (CFA) and further modified to enhance Be sorption. Results indicated zeolite NaP1 was effectively synthesised, and cross-linked chitosan was grafted in/on the zeolite structure during modification. The Brunauer, Emmett, and Teller (BET) surface area substantially increased from 1.05 m2/g in CFA to 94.0 m2/g in the synthesised zeolite (SZ). Furthermore, the modified zeolite (MZ) showed improved functionality as a reactive site for Be sorption. A comparative sorption study revealed inferior sorption (11.3 %) and higher desorption (56.1 %) of Be using CFA than the sorption using SZ (93.0 % sorption, 2.9 % desorption) and MZ (93.0 % sorption, 1.5 % desorption). Consequently, SZ and MZ exhibited higher sorption efficacy than commercial zeolite (57.4 %) and other commercial sorbents. At an experimental pH of 5.5 [relevant to the pH of Little Forest Legacy Waste Site (LFLS) soil, a representative site for potential Be contamination], MZ showed higher sorption than SZ. The higher sorption in MZ resulted from its elevated ligand complexation [with nitrogen (N), phosphorous (P), and oxygen (O)] and some ion exchange (with Na+, -NH3+, and H+ ions) mechanisms. Moreover, increased sorption (up to 99 %) was observed using colloidal soil solution (CSS) collected from LFLS soil to simulate field conditions after extensive rainfall. Different environmental factors (e.g. pH, temperature, time, CSS, concentrations of sorbate, and sorbent) regulated Be sorption. The sorption mechanism was best described by the Langmuir model, and the pseudo-second-order kinetic model (R2 = 0.999). Moreover, the sorption reaction was spontaneous (ΔG = -Ve), enthalpically, and entropically influenced. Desorption hysteresis (ndesorption/nsorption < 1) suggested irreversible sorption, and the chemisorption mechanism of Be was confirmed by Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analysis.

A molecularly imprinted polymer for microextraction by packed sorbent of sulfonylureas herbicides from corn samples

A molecularly imprinted polymer (MIP) was synthesized and assessed as a selective extraction phase in the microextraction by packed sorbent (MEPS) of sulfonylureas herbicides (SUHs) — Thifensulfuron, Chlorosulfuron, Tribenuron, and Bensulfuron — from grounded corn samples. Bensulfuron was employed as the template for the MIP preparation. MIP particles were chemically and structurally characterized. Distribution (Kd), selectivity (k), and relative selectivity (k') coefficients were estimated using binary mixtures of bensulfuron/betazon and bensulfuron/prometon. The most significant parameters affecting the MEPS performance were systematically studied in univariate and multivariate experiments. Analyses were performed by liquid chromatography coupled to time-of-flight mass spectrometry (LC-ToF). Under selected conditions, the developed MIP-MEPS-LC-ToF method demonstrated suitable analytical confidence and reliability. Determination coefficients (r2) higher than 0.9940, and limits of detection (LODs) of 2.5 µg kg-1 were obtained. Intra- and interday precision was lower than 14.2%, and accuracy ranged between 89.6% and 113.6%. The synthesized MIP demonstrated enhanced selectivity and higher SUHs uptake capability compared to the non-imprinted polymer (NIP) and tested commercial sorbents. Besides, the method is a cheap, feasible, and environmentally friendly analytical tool. A single MEPS device packed with 1.0 mg of MIP was reused more than 180 times without loss in its extraction capabilities.

Characterization of a solid-supported aqueous biphasic system for the sorption of dyes from aqueous solution

An aqueous biphasic system (ABS) comprising solutions of ammonium sulfate and polyethylene glycol-2000 (PEG-2000) in which the latter is supported on a porous polymeric substrate (Amberlite XAD-16) has been characterized by examining its performance in the removal of dyes from aqueous solution. Comparison of its behavior to that of a commercial sorbent (ABEC) consisting of a polyethylene glycol covalently bound to a polymer support indicates that the capacity, uptake kinetics, and efficiency of the supported ABS are comparable or superior to that of the ABEC resin. In addition, results obtained at various PEG-2000 concentrations and with PEGs of a range of molecular weights demonstrate that in contrast to ABEC resin, the behavior of a supported ABS can be readily “tuned” to provide the desired dye retention. The relative retention of various dyes is not generally predictable from their behavior in an analogous liquid-liquid system, however, the apparent result of synergistic effects between the XAD-16 support and the PEG phase.

Effects of Polydextrose Supplementation on Intestinal Function in Hemodialysis Patients: A Double-Blind, Randomized, Placebo-Controlled Trial

Intestinal constipation is a frequent complication in hemodialysis (HD) patients. Polydextrose (PDX), a nondigestible oligosaccharide, has been reported as a fermentable fiber with potential benefits. This study aimed to investigate the possible influence of PDX supplementation on intestinal function in HD patients. This randomized, double-blind, placebo-controlled trial included 28 patients who received daily oral supplementation with 12g of PDX or placebo (corn starch) for 2months. ROME IV criteria were used to define constipation and questionnaires were applied to patient assessment of constipation symptoms (PAC-SYM) and their impact on the patient assessment of constipation quality of life. The Bristol scale was used to assess stool consistency. Commercial Enzyme-Linked Immuno Sorbent Assay kits were used to evaluate the interleukin-6 and tumor necrosis factor-α plasma levels. 25 patients completed the study; 16 in the PDX group [7 females, 48.5years (IQR=15.5)] and 9 in the control group [3 females, 44.0years (IQR=6.0)]. According to ROME IV criteria, 55% of patients were diagnosed with constipation. PAC-SYM faecal symptoms domain was reduced after 2months of PDX supplementation (P=.004). We also observed a significant reduction in the PAC-QoL-concerns domain (P=.02). The average values for PAC-SYM and patient assessment of constipation quality of lifewere reduced significantly after intervention with PDX. There were no significant changes after the intervention period concerning biochemical variables, food intake, and inflammation markers. No adverse effects were observed during the supplementation period. The results of the present study suggest that short-term PDX supplementation may have favourable results on intestinal function and the quality of life of chronic kidney disease patients in HD.

Sorption affinity and mechanisms of per-and polyfluoroalkyl substances (PFASs) with commercial sorbents: Implications for passive sampling

Effective monitoring tools, including passive samplers, are essential for the wide range of per- and polyfluoroalkyl substances (PFASs) in aquatic matrices. However, knowledge of the extent and mechanisms of PFASs sorption with sorbents in a passive sampling context is limited. To address this, sorption behavior of 45 anionic, neutral and zwitterionic PFASs ranging in perfluorocarbon chain length (C3-C16) and functional groups with 11 different commercial sorbents (cross-linked β-cyclodextrin polymers, activated carbon, anion exchange (AE), cation exchange, hydrophilic-lipophilic balanced (HLB) and non-polar) was investigated. A broad range of equilibrium sorbent-MilliQ water (MQ) distribution coefficients (Kd) were observed (10−1.95 to 108.30 mL g−1). Similar sorbent types (e.g., various AE and HLB sorbents) exhibited very different sorption behavior, likely due to their different polymeric structures and relative importance of sorbate/sorbent interactions other than coulombic interactions. HLB and AE with hydroxyl functionalities are most effective for sampling of the full suite of PFASs. Reduced sorptive affinity was observed in the presence of matrix co-constituents in wastewater influent for most PFASs. HLB had the smallest reduction in log Kd in wastewater suggesting that these sorbents are appropriate for applications in complex matrices. Sufficient sorbent capacity was observed for linear uptake of many target analytes which facilitates passive sampling.