N-methyl-D-glucamine Research Articles

Boron adsorption studies of poly(styrene-glycidyl methacrylate) latex: effect of modification agents

Poly(styrene-glycidyl methacrylate) (PSGMA) latex was synthesized by emulsion polymerization method. PSGMA latex was modified with N-methyl-d-glucamine (NMDG), 1,2-bis(3-aminopropylamino)ethane (BAPE), N-(2-hydroxyethyl)ethylenediamine (HEA), and N,N'-dimethylethylenediamine (NMEA). The presence of N amount varying between 2.1 and 4.4% in the results of elemental analysis showed that the modification was successful. Boron adsorption studies were carried out using these modified latexes. The study was carried out using the curcumin method by UV–vis spectrophotometry. For the most effective adsorption process, at pH value of 9, the boron concentration was 10 ppm and the contact time was 60 min. It was found that latex modified with NMDG had a higher adsorption capacity (0.195 mmol/g) than other modified latexes. Particle sizes were determined by dynamic light scattering spectrometry and scanning electron microscopy (SEM) analyses. The particle diameter of PSGMA latex was found to be approximately 140 nm in SEM analysis and the particles were almost monodisperse. After PSGMA latex was modified with NMDG, BAPE, HEA, and NMEA agents and boron adsorption was performed, it was observed that the particle diameters increased to approximately 170, 270, 220, and 260 nm, respectively. An elemental analyzer was used to determine the %N of the structures. The %B2O3 of the structures was determined with a thermogravimetric analyzer. While thermal analysis studies showed that organic components were completely removed from the structure at 700 °C, residues ranging from 4.8 to 10.4% (%B2O3) were found in boron adsorption polymers. The %B amounts were determined with an inductively coupled plasma mass spectroscopy device. It was observed that the amount of adsorbed boron varied between 0.42 and 0.95%, and the highest amount of %B belonged to latex modified with NMDG due to its very simple structure and the location of the –OH groups.Graphical

Preparation and Performance Study of Boron Adsorbent from Plasma-Grafted Polypropylene Melt-Blown Fibers.

In this study, the plasma graft polymerization technique was used to graft glycidyl methacrylate (GMA) onto polypropylene (PP) melt-blown fibers, which were subsequently aminated with N-methyl-D-glucamine (NMDG) by a ring-opening reaction, resulting in the formation of a boron adsorbent denoted as PP-g-GMA-NMDG. The optimal conditions for GMA concentration, grafting time, grafting temperature, and the quantity of NMDG were determined using both single factor testing and orthogonal testing. These experiments determined the optimal process conditions to achieve a high boron adsorption capacity of PP-g-GMA-NMDG. Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy dispersion spectrum analysis (EDS), and water contact angle measurements were performed to characterize the prepared adsorbent. Boron adsorption experiments were carried out to investigate the effects of pH, time, temperature, and boron concentration on the boron adsorption capacity of PP-g-GMA-NMDG. The adsorption isotherms and kinetics of PP-g-GMA-NMDG for boron were also studied. The results demonstrated that the adsorption process followed a pseudo-second-order kinetic model and a Langmuir isothermal model. At a pH of 6, the maximum saturation adsorption capacity of PP-g-GMA-NMDG for boron was 18.03 ± 1 mg/g. In addition, PP-g-GMA-NMDG also showed excellent selectivity for the adsorption of boron in the presence of other cations, such as Na+, Mg2+, and Ca2+, PP-g-GMA-NMDG, and exhibited excellent selectivity towards boron adsorption. These results indicated that the technique of preparing PP-g-GMA-NMDG is both viable and environmentally benign. The PP-g-GMA-NMDG that was made has better qualities than other similar adsorbents. It has a high adsorption capacity, great selectivity, reliable repeatability, and easy recovery. These advantages indicated that the adsorbents have significant potential for widespread application in the separation of boron in water.

Preparation and Adsorption Performance of Boron Adsorbents Derived from Modified Waste Feathers.

This research focuses on modifying discarded feathers by grafting glycidyl methacrylate (GMA) onto their surface through thiolation, followed by an epoxy ring-opening reaction with N-methyl-D-glucamine (NMDG) to synthesize feather-based boron adsorbents. Optimization of the adsorbent preparation conditions was achieved through single-factor experiments, varying temperature, time, GMA concentration, and initiator dosage. The synthesized adsorbent (F-g-GMA-NMDG) underwent characterization using Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and X-ray diffraction (XRD). The adsorption behavior of the adsorbent was studied, and its boron adsorption capacity at different temperatures was determined through static adsorption kinetic curves. Analysis of adsorption isotherms, kinetics, and thermodynamics was conducted. Results indicate that the boron adsorption process by F-g-GMA-NMDG follows a pseudo-second-order model. The adsorption process is endothermic, with higher temperatures promoting adsorption efficiency. Gibbs free energy (ΔG) confirms the spontaneity of the adsorption process. Enhanced adsorption efficacy was observed under neutral and acidic pH conditions. After four cycles, the adsorbent maintained its adsorption efficiency, demonstrating its stability and potential for reuse. This study provides novel insights into both the treatment of discarded feathers and the development of boron adsorbents.

The predictive machine learning model of a hydrated inverse vulcanized copolymer for effective mercury sequestration from wastewater

Inverse vulcanized polysulfides (IVP) are promising sulfur-enriched copolymers with unconventional properties irresistible for diverse applications like Hg2+ remediation. Nevertheless, due to their inherent hydrophobic nature, these copolymers still offer low Hg2+ uptake capacity. Herein, we reported the synthesis of IVP by reacting molten sulfur with 4-vinyl benzyl chloride, followed by their functionalization using N-methyl D-glucamine (NMDG) to increase the hydration of the developed IVP. The chemical composition and structure of the functionalized IVP were proposed based on FTIR and XPS analysis. The functionalized IVP demonstrated a high mercury adsorption capacity of 608 mg/g (compared to <26 mg/g for common IVP) because of rich sulfur and hydrophilic regions. NMDG functionalized IVP removed 100 % Hg2+ from a low feed concentration (10–50 mg/l). A predictive machine learning model was also developed to predict the amount of mercury removed (%) using GPR, ANN, Decision Tree, and SVM algorithms. Hyperparameter and loss function optimization was also carried out to reduce the prediction error. The optimized GPR algorithm demonstrated high R2 (0.99 (training) and 0.98 (unseen)) and low RMSE (2.74 (training) and 2.53 (unseen)) values indicating its goodness in predicting the amount of mercury removed. The produced functionalized IVP can be regenerated and reused with constant Hg2+ uptake capacity. Sulfur is the waste of the petrochemical industry and is abundantly available, making the functionalized IVP a sustainable and cheap adsorbent that can be produced for high-volume Hg2+ remediation. Environmental implicationThis research effectively addresses the removal of the global top-priority neurotoxic pollutant mercury, which is toxic even at low concentrations. We attempted to remove the Hg2+ utilizing an inexpensive adsorbent developed by NMDG functionalized copolymer of molten sulfur and VBC. A predictive machine learning model was also formulated to predict the amount of mercury removal from wastewater with only a 0.05 % error which shows the goodness of the developed model. This work is critical in utilizing this low-cost adsorbent and demonstrates its potential for large-scale industrial application.

Functional analysis of plasma membrane Ca2+ATPase 3 and its primary aldosteronism-associated mutations.

Primary aldosteronism (PA) is the most common form of secondary hypertension and can lead to higher rates of cardiovascular complications and death than essential hypertension. Aldosterone-producing adenomas (APAs) are the most frequent cause of PA. Most APAs have mutations in plasma membrane ion-transport proteins with 0.6%-9% carrying a mutation in the Plasma Membrane Ca2+ ATPase 3 (PMCA3). We have developed a Xenopus oocyte expression system to measure the function of PMCA3 wildtype (PMCA3WT) and an APA associated deletion mutant (PMCA3L425_V426del.) with minimal endogenous contamination. We measured ATPase activity at 37 °C in plasma membrane preparations from oocytes expressing PMCA3. Ca2+-dependent ATPase was observed in preparations from oocytes expressing PMCA3WT, with a [Ca2+] dependence well described with a rectangular hyperbola (K0.5 = 25.6 ± 5.1 μM) (triplicates from three independent membrane preparations). In contrast, membrane preparations from PMCA3L425_V426del. expressing oocytes lacked Ca2+-dependent ATPase activity, indicating loss of enzymatic activity in the mutant. We used two-electrode voltage clamp electrophysiology to evaluate the presence of PMCA3-variant mediated currents. At resting intracellular [Ca2+], PMCA3WT-injected oocytes had currents indistinguishable from those in uninjected oocytes, at all voltages. When bathed by extracellular 125 mM Na+, PMCA3L425_V426del.-injected oocytes presented inward currents at negative membrane potentials and outward currents at positive ones, consistent with induction of an aberrant channel-like current. The currents were outwardly directed upon substitution of external Na+ with N-methyl D-glucamine+ and were insensitive to changes in extracellular [Ca2+]. These results indicate that PMCA3L425_V426del. causes hyperaldosteronism due to the concomitant loss of active Ca2+ transport and induction of a depolarizing Na+-mediated current. Current experiments are evaluating the ATPase and physiological characteristics of other PA-associated PMCA3 mutations. Funded by NSF-MCB 2003251.

Glucosamine for CO2 Capture: Absorption Kinetics, Promoted Absorption Rate, and Comparison with Other Amino Sugars

Amino sugars─sugars wherein the amine group substitutes the hydroxyl group─are renewable and ecofriendly CO2 separation solvents. In this work, the kinetics of CO2 absorption in the amino sugar glucosamine (GA) was studied. Absorption rates in aqueous GA solutions (0.1–1 M) were measured in a stirred cell reactor in the 303–313 K range. At T = 308 K, the value of the reaction rate constant for GA (0.1 M) was 27 M–1 s–1. The two-step zwitterion mechanism was employed for describing the reaction pathway. Some useful characteristics of GA solutions, such as density and viscosity, were measured. Using the modified Stokes law and the N2O analogy method, the diffusivity and solubility of CO2 in solutions were determined. The liquid-side mass-transfer coefficient was found to be 0.005 cm/s at 308 K. Three amine promoters were chosen to improve the reactivity of GA, viz., monoethanolamine (MEA), 2-amino-2-methyl-1-propanol (AMP), and piperazine (PZ). Mixtures of GA/PZ (2.5/0.5 M) were the most reactive. The reactivity of two further amino sugars, N-acetyl-d-glucosamine (NAG) and N-methyl-d-glucamine (NMG), was also studied, and a comparison with GA was provided. NMG was the most reactive with CO2, whereas GA was the least reactive. This work will draw attention to this new category of CO2-capturing solvents.

Novel Hybrid Adsorption-Electrodialysis (AdED) System for Removal of Boron from Geothermal Brine.

A novel hybrid adsorption-electrodialysis (AdED) system to remove environmentally harmful boron from geothermal brine was designed and effective operating parameters such as pH, voltage, and flow rate were studied. A cellulose-based adsorbent was synthesized from glycidyl methacrylate (GMA) grafted cellulose and modified with a boron selective n-methyl-d-glucamine (NMDG) group and characterized with SEM-EDX, FT-IR, and TGA analyses. Batch adsorption studies revealed that cellulose-based adsorbent showed a remarkable boron removal capacity (19.29 mg/g), a wide stable operating pH range (2-10), and an adsorption process that followed the Freundlich isotherm (R 2 = 0.95) and pseudo-second-order kinetics (R 2 = 0.99). In the hybrid AdED system, the optimum operating parameters for boron removal were found to be a pH of 10, a voltage of 10 V, a flow rate of 100 mL/min, and an adsorbent dosage of 4 g/L. The presence of the adsorbent in the hybrid system increased boron removal from real geothermal brine (containing 199 ppm boron) from 7.2% to 73.3%. The results indicate that the designed AdED system performs better than bare electrodialysis for boron removal from ion-rich real geothermal brine while utilizing environmentally friendly cellulose-based adsorbent.

Boron removal by glucamine-functionalized inverse vulcanized sulfur polymer

Boron removal by novel sulfur-based boron selective adsorbent is herein reported. The sulfur-based polymer prepared by the inverse vulcanization of sulfur and 4-vinylbenzyl chloride (VBC) under optimized reaction conditions was used as a substrate and further functionalized by N-methyl-D-glucamine (NMDG) under optimized reaction conditions. Batch adsorption boron removal tests showed that a pH of 9 results in the highest adsorption capacity while an increase in the adsorbent dosage also showed a non-linear increase in the removal capacity. Acid and alkali regeneration of the used adsorbent showed 86% of its initial capacity after five cycles. The equilibrium isotherms of the adsorption were best fitted with the Redlich-Peterson model indicating that the boron adsorption obeys the principles of both monolayer and multilayer adsorption with a Langmuir maximum adsorption capacity of 7.186 mg/g. On the other hand, pseudo-second-order best fitted the adsorption kinetics meaning that chemisorption is the main controlling mechanism. The thermodynamic studies showed an endothermic spontaneous adsorption process with an increased randomness degree at the solid/liquid interface after the adsorption. The developed adsorbent is the first sulfur-rich polymer and selective boron adsorbent that can effectively reduce boron in water while also offering a considerably lower price due to utilizing the cheap and already available elemental sulfur.

Removal of boron from aqueous solutions by N-methyl-D-glucamine@γ-glycidoxypropyl-trimethoxysilane with nonwoven basalt fibers support

Waste water with boron is a widespread environmental problem. This work presents a kind of novel organic-inorganic composite boron adsorbent of NGN, N-methyl-D-glucamine (NMDG) @γ-glycidoxypropyl-trimethoxysilane (GPTMS) on the nonwoven basalt fibers (NBF), which is environmentally friendly, water resistance, non-toxicity and low cost. The effect of various parameters on the adsorption performance of NGN, such as pH value, boron concentration, contact time and different ion concentrations, was investigated. The optimum adsorption capacity of 1.64 mmol/g occurred in the vicinity of pH 9.0, and NGN possessed the fast adsorption equilibrium of boron within 40 min. In the presence of competing ions, Na+ and Li+ had little effect on the adsorption of boron, while Mg2+ promoted the adsorption of boron. The features of NGN adsorption process were assessed by Langmuir and Freundlich adsorption isotherms. The experimental data of NGN boron adsorbent was well described by using the pseudo-second-order kinetic model. In addition, after eight times adsorption-desorption cycles, NGN still featured excellent regeneration performance. All the experimental results illustrate that NGN could be efficiently utilized for separating and recycling boron from aqueous solutions.

Application of Ion Exchangers with the N-Methyl-D-Glucamine Groups in the V(V) Ions Adsorption Process.

The adsorption capacities of ion exchangers with N-methyl-D-glucamine (NMDG) groups (Amberlite IRA 743, Lewatit MK 51, Purolite S110 and Purolite S108) relative to V(V) ions were tested in a batch system, taking into account the influence of various parameters, such as the adsorbent mass (0.05–0.20 g), phase contact time (1–240 min), initial concentration (10–150 mg/L), and temperature (293–333 K), as well as in a column system where the variable operating parameters were initial concentration (50, 100 mg/L), bed volume (10, 100 mL) and flow rate (0.6, 6 mL/min). Pseudo-first order, pseudo-second order, intraparticle diffusion and Boyd models were used to describe the kinetic studies. The best fit was obtained for the pseudo-second order model. The Langmuir, Freundlich and Temkin adsorption models were used to describe the equilibrium data to acquire better knowledge about the adsorption mechanism. The thermodynamic parameters were also calculated, which showed that the studied processes are endothermic, spontaneous and thermodynamically favorable. The physicochemical properties of the ion exchangers were characterized by nitrogen adsorption/desorption analyses, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray photo electron spectroscopy (XPS). The point of zero charge (pHPZC) was also determined.

Boric acid removal with polyol-functionalized polyether membranes

Poor selectivity of conventional desalination membranes for boron often necessitates multi-stage treatment trains to achieve desired boron removal for end uses such as irrigation. One approach to membrane design for improved single-pass boric acid removal is via incorporation of chelating ligands that selectively sorb boron. In this study, membranes based on epoxy-amine cross-linked poly(glycidyl glycidyl ether) (PGGE) were synthesized and functionalized with N-methyl-d-glucamine (NMDG), a polyol known to interact selectively with boron. PGGE and PGGE-NMDG membranes exhibited boron sorption isotherms that were well-described by dual mode isotherms. PGGE-NMDG sorbed 2.5 mmol B/g dry polymer from a neutral aqueous solution containing 100 mmol B/L, which was almost three times the adsorption density of a commercial boron selective resin, Amberlite IRA743. The membranes were regenerated in acid without a significant loss of boron sorption capacity over four cycles. Interactions between boron and NMDG and PGGE sites (e.g., epoxides) impacted boron diffusion in both membranes. The use of ligand functionalized membranes to capture target solutes such as boron requires high loading of interacting sites to maximize uptake capacity. Establishing fundamental structure/property rules for boron selectivity could lead to new material designs with improved boron separation properties for water purification.

Genetically and pharmacologically limiting RyR2 open time prevents neuronal hyperactivity of hippocampal CA1 neurons in brain slices of 5xFAD mice

Neuronal hyperactivity is an early, common manifestation of Alzheimer’s disease (AD), and is believed to drive AD progression. Neuronal hyperactivity in the form of baseline activity (or spontaneous Ca2+ transients) has consistently been demonstrated in mouse models of AD using two-photon in vivo Ca2+ imaging of cortical or hippocampal neurons in anesthetized animals. Notably, these AD-related spontaneous Ca2+ transients were hardly detected in acute hippocampal slices, probably due to neuronal damage during brain slicing. To better preserve neuronal activity, we employed the N-methyl-D-glucamine (NMDG) protective brain slicing protocol. We performed confocal in vitro Ca2+ imaging of hippocampal CA1 neurons in optimized hippocampal slices. Consistent with previous in vivo studies, our in vitro studies using optimized brain slices also showed that limiting the open duration of the ryanodine receptor 2 (RyR2) by the RyR2 mutation E4872Q or by the R-carvedilol enantiomer prevented and rescued neuronal hyperactivity of hippocampal CA1 neurons from 5xFAD mice. Thus, genetically and pharmacologically limiting RyR2 open time prevented and rescued AD-related neuronal hyperactivity in vitro in optimized brain slices in the absence of anesthetics’ influence. Our data also suggest that the NMDG protective brain slicing preparation offers an alternative means to study neuronal hyperactivity of various cell types in different brain regions, especially in regions that are not readily accessible to two-photon in vivo Ca2+ imaging.

Chelating Fabrics Prepared by an Organic Solvent-Free Process for Boron Removal from Water.

A chelating fabric was prepared by graft polymerization of glycidyl methacrylate (GMA) onto a nonwoven fabric, followed by attachment reaction of N-methyl-D-glucamine (NMDG) using an organic solvent-free process. The graft polymerization was performed by immersing the gamma-ray pre-irradiated fabric into the GMA emulsion, while the attachment reaction was carried out by immersing the grafted fabric in the NMDG aqueous solution. The chelating capacity of the chelating fabric prepared by reaction in the NMDG aqueous solution without any additives reached 1.74 mmol/g, which further increased to above 2.0 mmol/g when surfactant and acid catalyst were added in the solution. The boron chelation of the chelating fabric was evaluated in a batch mode. Fourier transform infrared spectrophotometer (FTIR) was used to characterize the fabrics. The chelating fabric can quickly chelate boron from water to form a boron ester, and a high boron chelating ability close to 18.3 mg/g was achieved in the concentrated boron solution. The chelated boron can be eluted completely by HCl solution. The regeneration and stability of the chelating fabric were tested by 10 cycles of the chelation-elution operations. Considering the organic solvent-free preparation process and the high boron chelating performance, the chelating fabric is promising for the boron removal from water.

High internal phase emulsion hierarchical porous polymer grafting polyol compounds for boron removal

Removing micro-pollutants is an important global challenge for the development of good adsorbents and environmental engineering issues. In this work, the structure of hierarchically and interconnected porous polymer has been fabricated by a high internal phase emulsion (HIPE) with water-in-oil and used for removing boron from water. This porous polymer was synthesized via monomer radical polymerization and utilized the active sites of monomer –Cl. In this way the vicinal hydroxyl group of N-Methyl-d-glucamine (NMG) was successfully introduced and grafted into HIPE by nucleophilic substitution reaction under the catalysis of triethylamine. The maximum boron uptake capacity was 2.54 mmol/g at a boron concentration of 100 mg/L, and reached adsorption equilibrium after about 2 h. Compared to traditional adsorption membrane materials, the HIPE porous polymer had better mechanical strength and able to resist acid and alkaline in the long-term. Meanwhile the regeneration efficiency of the HIPE30 %-g-PNMG porous polymer remained at 100 % after being used for 10 cycles.

Comparative modelling analysis of boron dynamic adsorption on fibrous adsorbent prepared using radiation grafting versus granular resin

A comparative study was carried to investigate the selective removal of boron from aqueous solutions over fibrous adsorbent and Diaion CRB03 granular resin in a fixed-bed dynamic column. The fibrous adsorbent was prepared by radiation induced grafting of vinylbenzyl chloride (VBC) onto nylon-6 fibres followed by treatment with N-methyl-D-glucamine (NMDG). The effect of variation of the space velocity (SV) on the breakthrough curves was investigated. The experimental boron adsorption data over both fibrous adsorbent and granular resin were analysed with various mathematical models such as Bohart-Adams, Thomas, Yoon-Nelson, Clark, and modified dose response (MDR) models using non-linear regression. The experimental adsorption data of both fibrous adsorbent and resin were found to best fit MDR model allowing the establishment of breakthrough curves. The fibrous adsorbent showed higher adsorption capacity values than granular resin at all space velocities (SV). This was accompanied by an increase in the adsorption capacity with the increase in SV from 20 to 100 h−1 unlike granular resin, which showed an opposite trend. The adsorbed boron was eluted using 0.1 M HCl and the regenerated adsorbent remained stable after adsorption/desorption 10 cycles. The results of this study suggest that the fibrous adsorbent prepared in this study outperformed the Diaion CRB03 granular resin reflecting its great potential for boron removal from aqueous solutions at pilot and industrial scaled applications.

Selective removal of boron from industrial wastewater containing high concentration of ammonia by radiation grafted fibrous adsorbent in fixed bed column

Removal of boron from real industrial wastewater containing high concentration of ammonia was investigated using a fibrous adsorbent bearing glucamine groups obtained by green method. The adsorbent was prepared by radiation induced emulsion grafting (RIEG) of glycidyl methacrylate (GMA) onto nylon-6 fibres and subsequent treatment with N-methyl-D-glucamine (NMDG) under controlled conditions. The performance of the obtained adsorbent was tested for adsorption of boron from a real industrial wastewater containing high concentration of ammonia in comparison with a synthetic aqueous solution using in a fixed bed-column under different feed space velocities (SV). The dynamic adsorption data of the fixed column was tested against three most common mathematical adsorption models: Yoon–Nelson, Thomas and Modified Dose-Response (MDR) models to predict breakthrough curves and determine the column design parameters. The results showed that the experimental breakthrough curves were best fitted by MDR model. The adsorbed boron was eluted with 1 M HCl solution and the adsorbent was regenerated for stability evaluation using 5 adsorption/desorption cycles. The results suggest that the obtained adsorbent has a strong potential for industrial pilot scale boron removal applications.

Reclamation of RO permeate and concentrate of geothermal water by new chelating resins having N-methyl-D-glucamine ligands

The paper presents a studies on decreasing boron and arsenic concentrations in processed geothermal water. Reverse osmosis leads to obtain permeate and concentrate characterized by concentrations of 3.99 and 9.82 mg B L−1, as well as 2.93 and 120 μg As L−1, respectively. This disqualifies the possible use of forth streams for irrigation and makes them inacceptable to be discharged to the surface aquifers. Hence, they have to be treated using chelating resins to further decrease concentrations of boron and arsenic. The new chelating resins 1PTN and 2PTN were synthesized by polymerization of vinylbenzyl chloride (VBC) within a matrix of Amberlite XAD-4 followed by the modification with N-methyl-D-glucamine (NMDG). The so-synthesized NMDG-functionalized resins were evaluated for the removal of boron and arsenic from RO streams and compared to commercial boron selective chelating resin (Diaion CRB 05). Removals and its kinetics followed the pseudo-second order model. Based on diffusional and reactional kinetic models, it was determined that diffusion in pores of the chelating resins was the critical step and the boron sorption rate of epidermal-activated resin was mostly controlled by the reacted layer mechanism.Based on the obtained results, it was found that the resin 2PTN, characterized by macroporous, epidermal-like structure revealed 94% removal of boron and 97% removal of arsenic from RO concentrate. These performances allowed to effectively decrease concentrations of both species to the permissible levels for drinking and irrigation water. What is more, the synthesized resins successfully competed with the commercial boron selective resin Diaion CRB 05 in the boron removal, and outperformed the commercial resin in the arsenic removal, making them a very attractive alternative for reclamation of geothermal water.

N-methyl-D-glucamine based cryogels as reusable sponges to enhance heavy metals removal from water

The design of novel cryogels containing N‐methyl‐D‐glucamine (NMG) group was herein reported. The macroporous materials were prepared via sustainable and feasible cryopolymerization by using as co-monomers (4‐vinyl-benzyl)‐N‐methyl‐D‐glucamine (VbNMG) and 2-hydroxyethyl methacrylate (HEMA) at different percentages. Particularly, cryogel containing 100% of VbNMG (VbNMG-100) showed excellent ability in fast water uptake, removing arsenic (V) and chromium (VI) metal ions from it. Reusability up to six cycles was also demonstrated. The as-prepared materials were characterized by spectroscopic, thermal, and morphological analyses. The effect of initial oxyanions concentration, kinetic profiles, interfering anions (phosphate and sulphate) were investigated and adsorption/desorption studies were carried out. Equilibrium sorption results well fitted the Langmuir isotherm for both ions tested, showing a startling aptitude in arsenic (76.3 mg/g) as well as chromium (130.9 mg/g) sorption properties if compared with similar polymers as well as other materials. Exploiting its spongy nature, only 5 mins were needed to absorb contaminated medium releasing purified water by a simple squeezing. Most importantly, the sponge can be easily regenerated and reused again up to three times without the depletion of its efficiency.

Mechanisms for pituitary adenylate cyclase-activating polypeptide-induced increase in excitability in guinea-pig and mouse adrenal medullary cells

Pituitary adenylate cyclase-activating polypeptide (PACAP) acts on adrenal medullary (AM) cells as a neurotransmitter of the sympathetic preganglionic nerve. In guinea-pig AM cells, PACAP induces little catecholamine secretion, but enhances secretion evoked by stimulants, whereas in other animals, such as mouse, PACAP itself induces depolarization and/or catecholamine secretion. The present studies aim to explore the physiological implication of these species differences in PACAP actions, the ion channel mechanism for PACAP-induced depolarization, and the mechanism for facilitation of muscarinic receptor-mediated cation currents in mouse and guinea-pig AM cells. The perforated patch clamp technique was used to record the whole-cell current in isolated AM cells. The amplitudes of 3 nM PACAP-induced inward currents were significantly larger in mouse AM cells than guinea-pig, whereas 1 μM muscarine-induced currents were larger in guinea-pig AM cells than mouse. Exposure to PACAP consistently resulted in enhancement of muscarine-induced currents in guinea-pig AM cells and facilitation of cell membrane insertion of heteromeric TRPC1-TRPC4 channels in response to muscarine in PC12 cells. The PACAP-induced current was inhibited by 30 μM 9-phenanthrol, a specific TRPM4 channel inhibitor, and abolished by replacement of external Na+ with N-methyl D-glucamine. TRPM4-like immunoreactivity was located at the cell periphery in AM cells. The present results indicate that PACAP and muscarinic receptors are major metabotropic receptors mediating generation of depolarizing inward currents in mouse and guinea-pig AM cells, respectively. We conclude that PACAP activates TRPM4-like channels and enhance the muscarinic current through facilitating the membrane insertion of TRPC1-TRPC4 channels in AM cells.

Surface-initiated ATRP of glycidyl methacrylate in the presence of divinylbenzene on porous polystyrene-based resins for boron adsorption

A boron sorbent having poly(glycidyl methacrylate) chains on the surface of porous polystyrene-based beads was prepared through atom transfer radical polymerization (ATRP), followed by the reaction with a boron selective N-methyl-d-glucamine (NMDG). The grafting yield was controlled by the ATRP reaction time and the amount of crosslinking agent, divinylbenzene (DVB). Here, we have found that the high grafting yield does not guarantee high boron adsorption capacity. As the grafting yield increases to accommodate more boron chelating sites, the boron adsorption capacity increases to 1.5–2 times compared to the resin without grafting chains, but decreases dramatically at over 100% grafting yield. This loss of linear relation between boron adsorption capacity and grafting yield is probably due to the decreased porosity and pore size. The morphological contribution of the grafted chains on the boron capacity would provide new directions to design sorbent architecture for better adsorption capability.