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© 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.In this work, the separations and preconcentrations of Zn(II) and Hg(II) ions on Bacillus lichenifoemis loaded onto Amberlite XAD-4 resin by solid-phase extraction has been performed. The biosorbent was characterized by using FT-IR, SEM, and EDX. pH, sample flow rate, eluent type and concentration, amount of B. licheniformis and XAD-4 resin, sample volume, and possible interfering ions effect were investigated in details as experimental variables in the SPE procedure. Limit of detection values for Zn(II) and Hg(II) were detected as 0.03 and 0.06 ng mL−1, respectively. 0.2–15 ng mL−1 linear range values were achieved for Zn(II) and Hg(II), respectively. Relative standard deviation values were found to be lower than 5%. For validation of the procedure, the certified standard reference materials (CWW-TM-D, EU-L-2, NCS ZC73O14, NCS ZC73350) were analyzed. The concentrations of Zn(II) and Hg(II) in water and food samples were measured by ICP-OES. Consequently, it can be inferred that the immobilized B. licheniformis microcolumn has ideal selectivity for Zn(II) and Hg(II) biosorption. Graphical abstract: [Figure not available: see fulltext.].

The main aim of this manuscript was to investigate the effect of amine (MEA, DEA and TEA) functionalization of high surface area supports (Amberlite IR120H, Ambersep 252H, Amberlite 200CNa and Amberlite XAD7HP) on adsorption of CO2 from gases streams. A saturated factorial design of experiments was initially applied to determine the influence of four amine impregnation variables on amine loading. Except for the amine concentration whose effect was significantly positive on the amount of ethanolamine impregnated in Amberlite XAD7HP (p ≤ 0.05), the other factors had negligible importance. Kinetic experiments of CO2 adsorption were performed in a fixed bed at different inlet concentrations of CO2 and temperatures. The amounts of adsorbed CO2 on the DEA enriched Ambersep 252H, Amberlite 200CNa and Amberlite XAD7HP at bed saturation were ~ 40–400 times as high as those obtained with the same adsorbents without impregnation. DEA enriched Amberlite IR120H and TEA functionalized resins presented small capacities to adsorb CO2 at the investigated conditions, while MEA enriched resins were effective as CO2 adsorbents in the case of impregnation in Amberlite 200CNa. A classical fundamental model described correctly the breakthrough curves for CO2 adsorption–desorption at concentrations of CO2 in the gas feed stream of 1%, 3% and 5% at 40 °C and 60 °C.

Current studies on the reactive extraction of fumaric acid with Amberlite LA-2 from aqueous phases with different viscosities using three solvents highlighted the influences of rheological properti...

R-2-(4-hydroxyphenoxy)propionic acid (R-HPPA) is a key intermediate for the synthesis of classic herbicides with high selectivity against grassy weed. The main route for R-HPPA biosynthesis is to hydroxylate the substrate R-2-phenoxypropionic acid (R-PPA) at C-4 position with microbes. In order to provide sufficient R-PPA for the industrial production of R-HPPA, an effective R-PPA synthesis method was established and optimized in this work. The synthesis process mainly consisted of two steps: (1) synthesis of S-2-chloropropionic acid from L-alanine via diazotization and chlorination reactions; and (2) synthesis of R-PPA from S-2-chloropropionic acid and phenol via etherification reaction. The optimal reaction conditions were as follows: HCl: NaNO2: KI: L-Ala = 2.0: 1.2: 0.7: 1.0 (in molar), 125 °C reflux for 1.5 h, with KI as catalyst, and KI: S-2-chloropropionic acid: phenol = 0.075: 1.2: 1.0 (in molar). Under these conditions, an improved molar conversion rate (74.9%, calculated in phenol) was achieved. After extraction using anionic exchange resin Amberlite IRA-400 (CI), R-PPA product with a purity of 95.08% was obtained. The purified R-PPA was identified and evaluated in the application of the biotransformative production of R-HPPA. The results indicated that the synthesized R-PPA supported the R-HPPA biosynthesis with a comparable yield as that of the standard R-PPA. The R-PPA synthesis method provided herein exhibited the advantages of low price and easy availability of raw materials, less toxicity of reagents, simple manipulations, and low equipment/instrument requirements.

Amberlite IRA 400 was impregnated with N, N’, N’-Tetramethylethylenediamine (ATMEDA) as well as N-Methyl benzyl amine (AMBA) and examined for uranium uptake efficiency from sulfate medium. The pote...

Background: The presence of heavy metal contaminants such as chromium, lead, mercury, cadmium, arsenic, nickel, and copper have become a major issue towards human health. Chromium is extremely toxic to living organisms as it acts as carcinogen and mutagen. High concentration of chromium may cause detrimental effects to human health in the long term. The mutagenic and carcinogenic properties, included Cr(VI) in the group “A” of human carcinogens. Cr(VI) can easily penetrate into the cell wall and exert its noxious effect due to its mobility in the environment. Cr(VI) is nearly 100 times more toxic than Cr(III). Cr(VI) causes skin and stomach irritation or ulceration, damage to liver, kidney ulceration, damage to nerve tissue, and long-term exposure above the maximum contaminated level even led to death. Therefore, it is essential to remove chromium from wastewater prior to its final discharge into the environment. This study attempts to explore the mechanism by which chromium ions had been adsorbed by these two ion exchange resins and will be extended further to investigate the uptake mechanism of other metal ions within future research. Methods: Equilibrium isotherms were obtained by contacting 20 mL of aqueous metal ion solution with different amounts of adsorbents in a shaker bath controlled at 25±0.5oC. The initial concentration of metal ion in the aqueous solution was varied between 40-100 mg L -1 . Equilibrium isotherms for the above metal ion were generated at pH 3, 4 and 5. The pH of the solution was varied between pH 3 to 5 using appropriate doses of buffer. Preliminary runs exhibited that the adsorption equilibrium was achieved after 1–1.30 h of contact time for both the tested resins. The adsorbents used were DOWEX and AMB resins. For estimation of adsorption enthalpy, adsorption equilibrium experiments were performed at temperatures 30, 40 and 55oC. The amount of metal ion adsorbed per unit mass of the adsorbent (mg g-1) was calculated as q= V∆C/W, where ∆C is the change in solute concentration (mg L -1 ), V is the solution volume (L) and W is the weight of the adsorbent (g). Experiments on adsorption kinetics were performed in a stirred constant volume vessel. The liquid volume was 100 cm3 with 10g of adsorbent sample. The initial concentration of metal ion was 80 mg L -1 at 25±0.5oC. The aqueous phase concentration was examined at equal time intervals till equilibration. Results: The electrostatic interaction of Cr(VI) with the positively charged nitrogen atom of the functional groups and chelation of Cr(III) with the electron donor groups were the possible mechanistic pathways through which the adsorption had occurred onto both the ion-exchange resins. Though electrostatic interaction was the predominant interaction in both the resins for the adsorption of anionic Cr(VI) species, but it had been observed that the mechanism of Cr(VI) adsorption was not only “anionic adsorption” but also the complexation of the reduced Cr(III) with the ammonium group of the resins. Thus, “adsorption- coupled reduction” was the main mechanism for the uptake of chromium ions. Conclusion: The present work demonstrated that both resins could effectively adsorb Cr(VI) ions from aqueous solution. More adsorption had taken place onto DOWEX compared to AMB. The adsorption characteristics of both the resins were studied under various equilibrium and thermodynamic conditions which proposed the spontaneous nature of the process. The adsorption capacities of both resins were influenced by the pH of the medium and exhibited high adsorption performances at pH 3. The mechanism of adsorption onto the two resins studied here was anionic adsorption of Cr (VI) and chelation of Cr (III) ion. The Cr(III) ions might have formed because of the reduction of Cr(VI) by the electron donor atoms present in the resins and interacted with the adsorbent surface. FTIR spectra also supported the interaction of chromium ions with functional groups present in the resin structures. Thus chromium uptake by DOWEX and AMB resins was mainly governed by “adsorption- coupled reduction”. Desorption studies revealed that regeneration of both the ionexchange resins are possible at basic pH and can be reused. However, the application of these two ion-exchange resins using real effluent is under consideration.

Within the present study, novel chelating resins containing a layer loaded with N-methyl-D-glucamine functionalities were synthesized. The procedure involved impregnation of macroporous Amberlite XAD-4 adsorbent using mixture of vinylbenzyl chloride (VBC) and divinylbenzene (DVB) further subjected to free radical suspension polymerization. The so-obtained 1PTN and 2PTN adsorbents were characterized by expanded-gel or microporous structure of VBC-co-DVB layer, respectively. The both materials were used in desalination of geothermal water aimed to decrease levels of boron and arsenic. As a part of this, he research on boron and arsenic removal included batch adsorption and kinetic studies. The results have shown that the resin 1PTN showed maximum boron removal of 64% and arsenic removal of 18% from the geothermal water. The resin 2PTN exhibited competitive boron removal performance as compared to the commercial Diaion CRB 05 resin, reaching its efficiency by removing over 96% of boron. Also, the sample 2PTN outmatched Diaion CRB 05, removing 97% of arsenic and leading to decrease of its concentration to permissible level., bilateral collaboration program between Turkey and Poland [TUBITAK-NCBR-2549, TuBTAK 117M023]; Turkish Higher Education CouncilMinistry of National Education - Turkey [YoK 100-2000], This research has been financially supported by bilateral collaboration program (TUBITAK-NCBR-2549) between Turkey and Poland (Project No: TuBTAK 117M023).; E. Altok is grateful for the PhD scholarship of Turkish Higher Education Council (YoK 100-2000). We thank Izmir Geothermal Co. for the kind support to get geothermal water samples. We also acknowledge Mitsubishi Chem. Japan for Diaion CRB 05 resin.

Complementary to hydrophobic five membered ring β-amino acids (e.g. ACPC), β-sugar amino acids (β-SAAs) have found increasing application as hydrophilic building blocks of foldamers and α/β chimeric peptides. Fmoc-protected β-SAAs [e.g. Fmoc-RibAFU(ip)-OH] are indeed useful Lego elements, ready to use for SPPS. The removal of 1,2-OH isopropylidene protecting group increasing the hydrophilicity of such SAA is presented here. We first used N3-RibAFU(ip)-OH model compound to optimize mild deprotection conditions. The formation of the 1,2-OH free product N3-RibAFU-OH and its methyl glycoside methyl ester, N3-RibAFU(Me)-OMe were monitored by RP-HPLC and found that either 50% TFA or 8 eqv. Amberlite IR-120 H+ resin in MeOH are optimal reagents for the effective deprotection. These conditions were then successfully applied for the synthesis of chimeric oligopeptide: -GG-X-GG- [X=RibAFU(ip)]. We found the established conditions to be effective and—at the same time—sufficiently mild to remove 1,2-O-isopropylidene protection and thus, it is proposed to be used in the synthesis of oligo- and polypeptides of complex sequence combination.

The one-pot synthesis of glycerol carbonate from carbon dioxide and glycerol was achieved using ion-exchanged Amberlite resin beads as metal-free heterogeneous catalysts. Two commercially available Amberlite resin beads consisting of polystyrene cross-linked with divinylbenzene and functionalized with either trimethyl ammonium chloride (IRA-900) or dimethyl ethanol ammonium chloride (IRA-910) groups were used as starting materials to prepare the catalysts. These polymeric beads were transformed into their iodide (Amb-900-I, Amb-OH-910-I) or hydroxide (Amb-900-OH and Amb-OH-910-OH) counterparts through straightforward ion-exchange reactions. First, the two resin bead catalysts in hydroxide form were tested in the base-catalyzed transcarbonation reaction of glycerol with propylene carbonate. Both resin bead catalysts were more active compared to benchmark basic catalysts as hydrotalcites and attained 80 % yield of glycerol carbonate over Amb-OH-910-OH after 2 h at 115 °C, employing a 4 : 1 ratio between propylene carbonate and glycerol. Then, the one-pot reaction of CO2, glycerol and propylene oxide to produce propylene carbonate, glycerol carbonate and propylene glycol was investigated as the main target of this study. The reaction involves two steps: the reaction of propylene oxide with CO2 yielding propylene carbonate, and the transcarbonation of the formed cyclic carbonate with glycerol. Amb-900-I, Amb-OH-910-I, Amb-OH-910-OH and combinations of the latter two were employed as catalysts. Although Amb-OH-910-I alone is poorly active in the transcarbonation reaction, it showed the highest catalytic activity in the one-pot cascade reaction, surprisingly surpassing the performance of the Amb-OH-910-I/Amb-OH-910-OH mixtures and reaching high yields of glycerol carbonate (81 %, 115 °C, 4 h). These findings led to proposing a mechanism for the one-pot reaction using the Amb-OH-910-I catalyst. The bead format led to easy recovery of the catalyst, which displayed good reusability in consecutive runs.

This paper presents the efficiency removal and thermodynamics studies of nitrates by using ion exchange resin, Amberlite IRA 900-Cl (AI900). The effect of experimental factors of contact time resin (1–6 h), resin dosage resin (1–6 g), initial concentration of nitrate influent in the range between 20 and 250 mg/L and temperature between 25 and 65 °C were studied by using a batch sorption method. From the overall study, the data clearly demonstrated that the optimum temperature for the nitrate ions were removed was at 25℃ as the sorption of nitrate decreased when the temperature increased. The sorption managed to obtain 85% removal of nitrates from bulk concentration by using 2 g of AI900 resin in 1-hour contact time. While increasing the contact time of resin until 6 h in 1 g resin and increasing the amount of resin to 6 g of AI900 resin in 1-hour contact time, the adsorption capacity managed to rise at 98 and 97%, respectively. AI900 resin demonstrated an exothermic and spontaneous process of nitrate removal at the varied temperatures as both enthalpy (ΔH°) and entropy (ΔS°) showed negative signs at −26.801 kJ/mol and −43 J/K∙mol respectively. The sorption was feasible and favored at low temperature as the Gibb energy (ΔG°) showed negative sign and decreased with the increasing temperature.

Extractant-impregnated resins have potential for recovering platinum group metals selectively and efficiently. Herein, 1,3-bis(2-(octylthio)propan-2-yl)benzene (1), a pincer-type extractant, was impregnated in Amberlite XAD-7 resin (1-EIR), and the batch Pd(II) sorption conditions, including impregnated amount, shaking time, Pd(II) concentration, HCl concentration, and Pd(II) desorption reagents, were optimized. The maximum Pd(II) sorption capacity of 1-EIR was 49 mg g−1 after 24 h in a 700 ppm Pd(II) solution. Over 20 adsorption–desorption cycles, 1-EIR showed good reusability, with a sorption percentage (S%) of > 92%. However, not all Pd(II) was desorbed from 1-EIR. Complete Pd(II) collection was achieved by combining desorption with flaking of the Pd–extractant complex from Pd(II)-loaded 1-EIR by Soxhlet extraction, as ~ 13 mg g−1 remained after the 20th adsorption–desorption cycle by absorptiometric method. The sorption mechanism was elucidated based on the Langmuir isotherm model, thermodynamic parameters, and sorption kinetics. Pd(II) sorption by 1-EIR was spontaneous and endothermic, and the sorption kinetics followed a pseudo-second-order model. Notably, 1-EIR also exhibited high selectivity for Pd(II) from a simulated mixed metal solution and a spent automotive catalyst leachate (S% = 98% and > 99%, respectively). Thus, this extractant-impregnated system is promising for selective Pd(II) recovery from spent automotive catalysts and other secondary resources.

In general, chromium is existed in stable oxidation states, such as Cr(III) and Cr(VI) in the environment. While a certain amount of Cr(III) is required for human metabolism, Cr(VI) is known to have toxic and carcinogenic effects for all living species. Chromium compounds are widely used in different fields, such as electroplating, dyeing, photographic and textile industries. Owing to this reason, it and its compounds can easily interfere with the water resources. Because of differences in toxicity, it is important to develop a sensitive analytical method for the speciation, preconcentration and determination of chromium species in the water resources. In this work, speciation and preconcentration of Cr(III) and Cr(VI) were performed using Amberlite CG-120 resin before detection step by flame atomic absorption spectrometry. The experimental conditions for model solutions were optimized so that Cr(III) was adsorbed in a column while Cr(VI) was not. To perform this, some experimental parameters, such as pH, eluent’ type/concentration/flow rate, sample solution flow rate and adsorbent amount were optimized. Furthermore, Cr(VI) was reduced to Cr(III) to determine total chromium. Then, Cr(VI) was calculated by the differences between total chromium and Cr(III). The limit of detection (3 s) and preconcentration factor were found to be 0.3 μg L–1 and 600, respectively. This proposed method was successfully applied for the determination of inorganic chromium species in the different spring waters supplied from Isparta province (Eyupler Village), Burdur province (Aglasun County), the commercial drinking water samples purchased from local market in Burdur province, and the waste water supplied from Isparta province (Suleyman Demirel Organized Industrial Region) at Turkey. The accuracy of the method was successfully checked by certified reference material (TMDA-70.2 Ontario Lake water) at 95% confidence level.

Hydrogen production via chemical processes has gained great attention in recent years. In this study, Co-based complex catalyst obtained by adsorption of Co metal to Amberlite IRC-748 resin and Diaion CR11 were tested for hydrogen production from alkaline NaBH4 via hydrolysis process. Their catalytic activity and microstructure were investigated. Process parameters affecting the catalytic activity, such as NaOH concentration, Co percentage and catalyst amount, as well as NaBH4 concentration and temperature were investigated. Furthermore, characteristics of these catalysts were carried out via SEM, XRD and FT-IR analysis. Hydrogen production rates equal to 211 and 221 ml min−1 gcat−1 could be obtained with Amberlite IRC-748 resin and Diaion CR11 Co based complex catalysts, respectively. The activation energies of the catalytic hydrolysis reaction of NaBH4 were calculated as 46.9 and 59.42 kJ mol−1 for Amberlite IRC-748 resin and Diaion CR11 based catalysts respectively kJ mol−1 from the system consisting of 3% Co, 10 wt% NaBH4 and 7 wt% NaOH as well as 50 mg catalyst dosage. It can be concluded that Co-based resins as catalysts for hydrogen production is an effective alternative to other catalysts having higher rate.

Platinum(IV) was extracted from chloride solution using kerosene solution of trioctyl ammonium chloride, methyltrioctylammonium chloride, and tetraoctyl ammonium chloride ionic liquids as solvents in high yields. To increase the Pt(IV) recovery and heterogenize the process for easy handling at industrial scale, these three ionic liquids were directly impregnated on some solid carriers, such as silica gel-60, silica gel-100, Amberlite XAD-7 ion-exchange resin, and Amberlite XAD-7 ion-exchange resin to form sorbents in nature of supported ionic liquid phase. The influence of some factors, such as ionic liquid and solid carrier structure, IL/Pt molar ratio, and ionic liquid loading as well as sorption isotherms, was investigated. The stripping and desorption of Pt(IV) using different eluents and reusability of ionic liquids and supported ionic liquid phases were also evaluated.

Water steam distillation is a classical method of rose oil production from the flowers of Rosa damascena Mill. This process produces considerable amount of waste water. In this study, ion-exchange column chromatography (Amberlite was the stationary phase) was used to prepare polyphenol-enriched fraction of waste water with improved biological activity. Phenol, flavonoid, and anthocyanin contents were examined before and after using column. Antioxidant activities, DNA protection ability, xanthine oxidase inhibition, and cytotoxicity of this fraction were also determined. The use of Amberlite increased phenol, flavonoid, and anthocyanin contents in fraction compared to the sample before fractionation. The IC50 values of various antioxidant assays comprises 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH), ferric-reducing antioxidant power assay (FRAP), and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) which were 226.66 ± 1.25, 126.03 ± 0.11, and 241.43 ± 0.33 for waste water, and these values for fraction were 63.21 ± 0.90, 34.6 ± 0.17, and 50.59 ± 0.75 μg/ml, respectively. The Trolox equivalent values of fraction in oxygen radical absorbance capacity (ORAC) assay were 0.34 ± 0.04, and the EC50 values in cellular antioxidant activity were 91.24 ± 0.32 μg/ml. The xanthine oxidase inhibition capacity of fraction (100 μg/ml) was 96.4 ± 0.02% μg/ml. The comet assay analysis showed that this fraction (25–100 μg/ml) protects human lymphocytes against H2O2-induced DNA damages significantly. The IC50 values of cytotoxicity assay were 248.145 ± 35.56 and 227.14 ± 16.51 μg/ml after 24 and 48 h, respectively. There has been great attention to the valorization of waste materials. Recovered fraction could be considered as a proper antioxidant, DNA damage-protection agent, and xanthine oxidase inhibitor. Using a nontoxic solid phase such as Amberlite is a fruitful way to concentrate bioactive ingredients which can be used in pharmaceutical and nutraceutical industry.

Four ionic liquids (ILs) 1-methyl-3-tetradecylimidazolium chloride ([C14MIM]Cl), 1-n-butyl-3-n-butylimidazolium chloride ([C4BIM]Cl), 1-n-butyl-3-n-tetradecylimidazolium chloride ([C14BIM]Cl), and 1-tetradecylpyridinium chloride ([C14Py]Cl) were synthesized. Sorbents in nature of supported ionic liquid phases (SILPs) were prepared by impregnating ILs on solid carriers such as silica gel, XAD-7 and XAD-4 Amberlite ion exchange resins. Pt(IV) was recovered using these sorbents with the yields over 90%, however, the amounts of used ILs are much less than those of ILs used in extraction method and the process can easily be transferred to heterogeneous phase. The Pt(IV) sorption is affected by the structure of ILs and solid carriers, the IL loading, and IL/Pt molar ratio. The highest sorption yields were observed when using [C14MIM]Cl-based SILPs. Moreover, the sorption isotherms of [C14MIM]Cl/SiO2 SILPs with different IL loadings and IL/Pt molar ratios were investigated and sorption mechanism was also proposed.

In the current study, adsorption behaviors of amberlite XAD-7 and XAD-16 for the removal of methylene blue from its aqueous solutions have been reported with several respects. First, response surfa...

Since graphene is a miracle material of the 21st century, a considerable number of researchers have studied the oxidation of graphite to synthesize graphene oxide and its applications. In this study, polymeric resin (amberlite XAD7HP) supported graphene oxide (GO) nanocomposite was synthesized successfully. Analytical methods, namely Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM) were utilized to characterize the new structure. Methylene blue (MB) solution was selected as a model discharged textile wastewater for adsorption application of synthesized nanocomposite. The adsorption data were modelled by response surface methodology (RSM), random forest (RF) and artificial neural networks (ANN) methods. The optimal condition parameters, which maximize the adsorption uptake capability, were determined by the genetic algorithm. Statistical errors and correlation coefficient values of each developed model were calculated independently to compare models’ performance. According to the results, the developed RF model outperformed the other models. On the other hand, the ANN model had the lowest correlation coefficient value among the models.

In this research, two biocomposite materials, namely Amberlite IRA-400 Cl resin/A. campestris and Amberlite 4200 Cl resin/A. campestris, were used to perform the biosorption of Brilliant Blue G from aqueous solution. The biosorption of dye was evaluated by using a batch system. In addition, the effect of some physicochemical and kinetic parameters of the medium such as pH, temperature, contact time and initial concentration was determined. In this research, pH (3–11), adsorbent dosage (0.3 g), initial dye concentration (10–150 mg L−1), temperature (298–318 K) and contact time (10–95 min) were investigated. In the 95th minute, biosorption reaches a maximum of 137.18 mg/g at the highest temperature (318 K). Brilliant Blue G biosorption increased for both materials and at pH 11 values reached 149 mg/g on IRA-400 Cl resin/A. campestris and 142 mg/g on IRA-4200 Cl resin/A. campestris. The characterization of adsorbents was done by scanning electron microscopy, element detection X-ray and Fourier transform infrared spectroscopy. The adsorption isotherms were examined for the biosorption process. The Harkins–Jura isotherm shows better fit than the other isotherms for IRA-4200 Cl resin/A. campestris, and the Freundlich isotherm is a better fit in the temperature range studied than the other isotherms for IRA-400 Cl resin/A. campestris biocomposite. Thermodynamic values such as enthalpy, change in entropy and Gibbs free energy were measured, and the biosorption process was found to be spontaneous and endothermic. As a result, IRA-400 Cl resin/A. campestris is a suitable biosorbent and has more typical proximity than IRA-4200 Cl resin/A. campestris biocomposite for biosorption of Brilliant Blue G from aqueous solutions.

Pb(II) ions were separated/preconcentrated and detected by a two-step preconcentration method (Amberlite CG-120 resin and slotted quartz tube (SQT) flame atomic absorption). The first preconcentration step was the adsorption of Pb(II) on Amberlite CG-120 resin in the drinking, spring and lake water samples before detection and then its elution using 5 mL of 3 M nitric acid. The second preconcentration step was conducted using SQT device with flame atomic absorption detection. Using a two-step preconcentration method, enrichment factor of 560 was found and detection and quantitation limits were 0.23 and 0.8 µg/L, respectively. The accuracy of the method was tested by analysis of standard reference material (Environmental Matrix Reference Material, Lake Water, TMDA-70.2) at a 95% confidence level.

Two porous Amberlite resin beads consisting of ammonium-functionalized polystyrene cross-linked with divinylbenzene were demonstrated to be efficient, easily recyclable, and viable metal-free heterogeneous catalysts for the reaction of CO2 with epoxides to yield cyclic carbonates. The catalysts were prepared from two affordable, commercially available resin beads, which differ in the nature of their functional groups, i.e., trimethylammonium chloride or dimethylethanolammonium chloride. These materials were converted through a straightforward ion-exchange step into their iodide counterparts (Amb-I-900 and Amb-OH-I-910). The ion-exchanged resin beads were tested as heterogeneous catalysts for the reaction of CO2 with styrene oxide at different reaction conditions (45-150 °C, 2-60 bar of CO2, 3-18 h). The effect of the presence of water as a hydrogen-bond donor in combination with a heterogeneous catalyst was systematically investigated here for the first time. With both catalysts, the presence of water led to higher yields of cyclic carbonate (from 12% to 58% with Amb-I-900 and from 59% to 66% with Amb-OH-I-910; ≥98% selectivity). The highest catalytic activity was observed with Amb-OH-I-910, due to the presence of -OH groups in its active site, which together with water enhanced the activity through hydrogen-bonding interactions. This catalytic system attained higher turnover numbers and turnover frequencies (TON = 505, TOF = 168 for reaction at 150 °C) and improved cyclic carbonate productivity compared to the state-of-the-art supported polymeric bead catalysts and was active in catalyzing the synthesis of styrene carbonate also at low temperature (33% yield at 45 °C and 10 bar of CO2). Additionally, the Amb-OH-I-910 proved to be a versatile catalyst for the conversion of a variety of epoxides into their corresponding cyclic carbonates with good to excellent yields and very high selectivity (≥98%). The two polymeric bead catalysts could be easily recovered and reused without significant loss in their activity and thus represent an easily accessible, environmentally friendly, cost-effective catalytic system for the synthesis of cyclic carbonates from CO2.

Naringenin, a natural plant flavonoid found in citrus fruits, has been reported to exhibit a wide range of pharmacological functions, including anticancer, antioxidant, antiatherogenic, antithrombotic, and vasodilator activities. Naringenin can be produced from the naringinase (NGase)-catalyzed enzymatic hydrolysis of naringin. However, the poor solubility of naringin in aqueous systems considerably limits the efficiency of naringenin biocatalysis. In this work, a novel substrate adsorption system was proposed for naringin adsorption to increase the efficiency of naringin hydrolysis and naringenin production. Three Amberlite macroporous resins, namely, XAD-4, XAD-7HP and XAD-16, were investigated for their naringin adsorption capacities and effects on NGase hydrolysis. Results indicated that the physical properties of the resins played a critical role in naringin adsorption and naringenin enzymatic synthesis. Naringin hydrolysis was carried out using free and adsorbed substrates. The substrate adsorption strategy could increase the catalytic efficiency at a high naringin concentration. In addition, the reaction conditions for enzymatic naringenin synthesis were optimized, and naringenin was prepared at a liter scale with a high substrate concentration. These results suggested that substrate adsorption is a promising strategy to increase the enzymatic hydrolysis efficiency of naringenin in aqueous systems.

Resins, when impregnated with a solvent shows better stability, higher affinity, and effectiveness in removing pollutants. The interaction of pollutants with the impregnated resin takes place by ad...

Preparation of single-walled carbon nanotubes (SWCNTs) with carboxylic (–COOH) acid was executed by functionalization with amine functional groups (–NH2). The obtained functionalized SWCNTs were supported by macroporous resin (amberlite XAD-7HP). The synthesized nanocomposite has been characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) methods. FTIR analysis indicates that functionalized SWCNTs supported onto the amberlite resin were synthesized successfully. The surface morphology of the nanomaterial was also successfully embedded into the amberlite of the functionalized SWCNTs. Huge solid residues of onions are produced as agricultural and food wastes each year. The related biowaste includes biologically active phenolic compounds which have positive effects with strong antioxidant properties on human health when properly isolated and concentrated. In the present research, functionalized SWCNTs have been utilized for the separation of bioactive phenolics from onion waste extracts. Equilibrium (Langmuir, Freundlich and Toth) and kinetic (pseudo-first order, pseudo-second order, intraparticular diffusion and Elovich) models have been applied for analysis and representation of data. Pseudo-second-order model is in good agreement with the experimental data. On the other hand, the equilibrium findings were represented best with Freundlich isotherm model. Additionally, thermodynamic indicators have also demonstrated that the current system is a spontaneous and exothermic chemisorption process.

A series of 1,3-diphenylpyrazole-chromenoquinolin-6-one compounds were designed and synthesized by using a greener and recyclable heterogeneous Amberlite IR-120H resin as a catalyst, in the presence of ethanol reflux conditions. Interestingly, the catalyst can be recovered after completion of the reaction and can be reused without loss of catalytic property. Therefore, this method provides a green and environmentally benign much improved protocol for the synthesis of 1,3-diphenylpyrazolechromenoquinolin-6-one compounds. The synthesized library of thirty compounds were tested against their cytotoxicity; moreover, the compounds 5s and 5t exhibited potential cytotoxic activity with IC50 values of 1.22 and 1.64 µM, respectively, on MCF-7 cancer cells. The biophysical studies such as UV-visible, fluorescence and circular dichroism studies indicate that these compounds possess good DNA intercalation ability. In addition, these compounds efficiently inhibit topoisomerase I activity. Molecular docking and viscosity studies support that these compounds exhibited intercalative mode of binding with DNA.

Tall oil fatty acids were epoxidized by in-situ generation of peracetic acid in the presence of two different acidic catalysts, commonly used catalyst—sulfuric acid and ion exchange resin. The described epoxidation was carried out without the use of organic solvents to comply with the principles of Green chemistry. The epoxidation process was monitored by the change of the relative oxirane conversion and alkenic unsaturation. Furthermore, the changes in the chemical structure of the epoxidized tall oil fatty acids were investigated using FTIR spectroscopy. It was shown that ion exchange resin Amberlite IR-120 H catalyst was superior to sulfuric acid catalyst as it delivered fewer by-products from oxirane group opening reactions. The oxirane value reached up to 2.31 mmol/g of epoxy groups, which is 41.9% of theoretically possible oxirane oxygen yield, when tall oil was epoxidized using Amberlite IR-120 H. The reusability of ion exchange resin was also studied, the 6.2% decrease in relative oxirane conversion value was registered after Amberlite IR-120 H was reused up to 10 times.

Malachite green dye was removed using three different polymeric resins (Amberlite XAD7, Amberlite 120H and Amberlite IRA67). Equilibrium and kinetic experiments were carried out to determine the ef...

Sorption of a series of alkaline earth and nonferrous metals (Ca, Mg, Cu, Ni, and Zn) from lithium hydrocarbonate and chloride solutions onto ion-exchange resins of various classes was studied. The highest values of the static exchange capacity were observed in sorption from a LiHCO3 solution onto imino carboxylic ion exchangers Amberlite IRC 748 (Rohm and Haas, the United States), Purolite S930 (Purolite, the United Kingdom), and AXIONIT 3S (AO Aksion RDM, Russia). In sorption from a LiCl solution with рН 1.4, the sorption capacity of all the sorbents tested is 3–7 lower. Sorption treatment of a LiHCO3 solution to remove Na, K, Са, Mg, Al, Si, Ti, Cr, Mn, Fe, Ni, Cu, and Zn impurities under dynamic conditions using AXIONIT 3S imino carboxylic sorbent was performed. The sorption ensures deep removal of Ca, Cu, and Zn impurities from a LiHCO3 solution. A procedure was suggested for preparing high-purity lithium carbonate by ion-exchange purification of a LiHCO3 solution on an imino carboxylic sorbent, followed by thermal decomposition of the purified solution at the boiling point to obtain a lithium carbonate precipitate. Lithium carbonate with the main substance content of 99.90 ± 0.05 wt % was obtained.

Esterification of isoamyl alcohol with acetic acid was studied using different ion-exchange resins, namely Amberlyst 15 dry, Amberlyst 16 wet, Amberlite 120-IR. Esterification was carried out using different esterification methods that are quite new (ohmic, ultrasonic probe, and ultrasonic bath) and the results were compared with microwave-assisted esterification (MAE). The highest isoamyl acetate yield (99%) was obtained by MAE, using a mixture of acetic acid and isoamyl alcohol (mole ratio of 1:2) after 2 h of reaction time. In this process, 2% Amberlyst 15 dry was used. MAE had the least specific energy consumption (0.42 kWh/g isoamyl acetate) and specific CO2 emission (34 g/g isoamyl acetate). According to the images obtained by scanning electron microscopy, lower amounts of Amberlyst 15 dry beads were destroyed by MAE method compared to other esterification methods. In conclusion, MAE proved to be an economic and environmentally-friendly method for esterification of different flavoring compounds.

Amberlite XAD-2 functionalized by coupling through -C=N- spacer with isatin via an environmental friendly protocol. The modified resin was used for the evaluation of its sorption capacity towards toxic Cr (VI) ions using spectrophotometer. pH, volume, sorbent amount, initial concentration of Cr(VI) ions, and agitation time were optimized. The Freundlich and Dubinin- Radushkevich models gave better fit to isotherm data than Langmuir model. The evaluation of kinetic data indicated pseudo-first-order kinetics followed by sorption process. Thermodynamic parameters were also evaluated. Maximum recovery was obtained at 10 mL of 0.1M NaOH. Spiking methodology was used to confirm the validity of proposed method. The results revealed that developed method can be used for the removal of Cr(VI) ions efficiently from water, as well as reused for three cycles.

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

The hydrophobic adsorption is an alternative to traditional organic solvent extraction for the recovery and purification of Penicillin G (PenG). However, there is a lack of information concerning the effect of process variables and technical feasibility while balancing product degradation. After assessing the integrity of PenG under different conditions, Amberlite XAD-4 was selected from among three different adsorbents. During the batch process using only 0.05 gXAD-4/mLmedium, the adsorption yield increased from 36% at pH 6 to 44% at pH 4. More than 90% of the antibiotic was captured from the fermentation broth using 0.083 gXAD-4/mLmedium in a 45 min batch performed at pH 4 and 4 °C. Moreover, there was no PenG degradation. The desorption conditions were evaluated, and 95% of the antibiotic could be recovered in only one batch using water-ethanol, which is an unexplored PenG desorption process. The results showed selective adsorption, indicating that the process can also be useful for purification purposes. Hydrophobic adsorption with ethanol desorption is efficient, scalable, and green and could be used in place of traditional methods or in extractive fermentation.

New adsorbent material was obtained by modification of commercial Amberlite XAD7 with thiourea that represents a non-toxic, cheap and environmentally friendly extractant. Prepared adsorbent was used for removal of neodymium ions from aqueous solutions. Thiourea modified Amberlite involved in this study shows good adsorption capacities (74.3 mg/g) and excellent efficiency during Nd removal process. In order to elucidate the mechanism of the Nd adsorption process kinetic, thermodynamic and equilibrium studies were performed, establishing this way which kinetic model better describes the Nd adsorption process. Moreover the thermodynamic studies prove that the Nd adsorption on thiourea modified Amberlite XAD7 is an endothermic and spontaneous process.

An analytical procedure regarding the trace determination of molybdenum in natural water samples by adsorptive stripping voltammetry (AdSV) using the in situ plated lead film electrode (PbFE) was described. The method is based on adsorptive accumulation of the Mo(VI)-cupferron complex at the PbFE surface. The optimum analytical conditions include the supporting electrolyte containing 0.2-mol L−1 acetic buffer pH = 5.3, 1.45 × 10−4-mol L−1 Pb(II), and 2.0 × 10−4-mol L−1cupferron. A linear response of Mo(VI) in the concentration range of 3.0 × 10−8 to 1.0 × 10−6 mol L−1 (r = 0.997) was obtained with detection limit of 9.0 × 10−9 mol L−1 using accumulation time of 50 s. The selectivity of the method was determined by investigating how the presence of foreign ions affects the determination of molybdenum. The interferences of surface-active substances and humic substances on the molybdenum voltammetric signal were precisely examined and effectively minimized by preliminary mixing with Amberlite XAD-7 resin. The application of the proposed procedure to the analysis of natural water samples was validated by the determination of molybdenum in certificate reference materials SPS-SW1 surface water, Bystrzyca river, tap, and mineral water.

Waste fractions of food processing are promising sources of polyphenols, which are of high demand because of their favourable bioactivities. More recently, also wastewater and process water fractions are in focus of research and technologies for downstream processing, which is reviewed here. Adsorption as well as membrane technologies are widely used to achieve selective recovery of polyphenols from waste water. For technical implementation the processing of waste fractions must be separated from the primary food production process. Therefore, the key step is the efficient transfer of the waste fractions into a storable and transportable form of polyphenol-enriched fractions. This strategy is shown exemplarily for the marzipan production. Almond skin and blanch water are waste fractions containing catechin and procyanidins, for which a recycling concept has been developed. The polyphenolic ingredients of the blanch water can be specifically adsorbed by means of Amberlite resins or zeolites with high yield followed by ultrafiltration.

The adsorption of methyl orange (MO) in aqueous solution was evaluated using a cationic polymer (Amberlite IRA 402) in batch experiments under different experimental variables such as amount of resin, concentration of MO, optimum interaction time and pH. The maximum adsorption capacity of the resin was 161.3 mg g−1 at pH 7.64 at 55 °C and using a contact time of 300 min, following the kinetics of the pseudo-first-order model in the adsorption process. The infinite solution volume model shows that the adsorption rate is controlled by the film diffusion process. In contrast, the chemical reaction is the decisive step of the adsorption rate when the unreacted core model is applied. A better fit to the Langmuir model was shown for equilibrium adsorption studies. From the thermodynamic study it was observed that the sorption capacity is facilitated when the temperature increases.

Heavy metal ions such as hafnium, zirconium, vanadium, nickel, iron, and uranium were separated from petroleum ash leach liquor using ion-exchange resins Dowex 1×8, A2S3B8, and Amberlite (IRA-420). The separation was studied using Fourier transform IR spectroscopy (FT-IR) to confirm the adsorption of the metal ions onto the organic resins. Possible reactions between the metal ions and organic resins were suggested on the basis of the FT-IR spectra. The results show that the Dowex resin takes up U, Hf, and Zr most efficiently. This fact can be attributed to the ability of the Dowex resin to reduce both vanadium(V) and iron(III) metal ions to the lower valence state. This reduction facilitates the absorption of U, Hf, and Zr ions. The results obtained by ICP-OES and FT-IR are compared.

Immobilization of enzymes is a good field of study to extend the life of enzyme and reduce the cost of the chemical processes, such as separation processes. Urease is an important enzyme with medical and industrial applications. The aim of the present study is to prepare an immobilized urease on a strong cation exchange resin (Amberlite IR120 Na) and study its activity and stability. We monitored the release of Na ions in the collected fractions and searching for enzyme in the fractions as indicators of immobilization by ion exchange phenomenon. Sodium is determined by using atomic absorption spectroscopy technique, while the enzyme concentration was tested by Bradford’s method. Immobilized urease activity was evaluated by salicylate-hypochlorite method. The results indicated a complete immobilization of urease enzyme on the resin surface with reserving 92% of the activity of free enzyme. The immobilized urease enzyme on resin showed good stability and it has a 62% of its activity after 154 days of storage at room temperature. It is concluded that a new immobilized urease enzyme system is prepared with good enzyme activity and stability.