Weak Acid Cation Exchange Resin Research Articles

Selective Immobilization of His-Tagged Enzyme on Ni-Chelated Ion Exchange Resin and Its Application in Protein Purification.

Ion exchange resins are suitable as carriers for immobilized enzymes because of their stable physicochemical properties, appropriate particle size and pore structure, and lower loss in continuous operation. In this paper, we report the application of the Ni-chelated ion exchange resin in the immobilization of His-tagged enzyme and protein purification. Acrylic weak acid cation exchange resin (D113H) was selected from four cationic macroporous resins that could chelate the transition metal ion Ni. The maximum adsorption capacity of Ni was ~198 mg/g. Phosphomannose isomerase (PMI) can be successfully immobilized on Ni-chelated D113H from crude enzyme solution through chelation of transition metal ions with the His-tag on the enzyme. The maximum amount of immobilized PMI on the resin was ~143 mg/g. Notably, the immobilized enzyme showed excellent reusability and maintained 92% of its initial activity with 10 cycles of catalytic reaction. In addition, PMI was successfully purified using an affinity chromatography column prepared by Ni-chelated D113H, which showed the potential for the immobilization and purification process to be realized in one step.

Proof-of-Concept study of ion-exchange method for the recycling of LiFePO4 cathode

Recycling spent lithium iron phosphate (LFP) cathodes in an economically sustainable way remains a great challenge due to their low-value elemental composition. Thus, both low-cost technology together with a high-value product are critical for the recovery of the LFP materials. In this study, the commercially mature ion-exchange (IX) method was explored to recover Li from LFP material for the first time. The feasibility of Li-H and Li-K IX reactions using strong and weak acid cation exchange resins was systematically investigated from the thermodynamic and kinetic perspectives. Different organic and inorganic acids were explored to obtain the feeding solution. The IX efficiency was greatly affected by the pH of the feeding solutions. Oxalic acid leaching solution with mild pH value and low iron impurity were determined to be the optimal feeding solution for IX reaction. The kinetics of IX and regeneration reaction were fast, and the resins can be reused several times without loss of IX capacity. Along with the P element remaining in the leaching solution, the Li-K IX reaction delivered a potential product of multi-elemental fertilizer. This simple and economical technology provides a practical recycling strategy for the spent LFP batteries.

Electrified Ion Exchange Enabled by Water Dissociation in Bipolar Membranes for Nitrogen Recovery from Source-Separated Urine.

Ion exchange (IX) is a promising technology for selective nitrogen recovery from urine; however, IX requires chemical-intensive regeneration that escalates energy consumption and carbon emissions. To overcome this barrier, we demonstrated and investigated a novel electrified IX stripping process (EXS) enabling electrochemical in situ IX regeneration with simultaneous ammonia stripping. EXS combines a weak acid cation exchange resin (WAC) to concentrate ammonia, a bipolar membrane to produce protons for WAC regeneration, and membrane stripping to recover the eluted ammonium from WAC. We observed over 80% regeneration (elution from resin) and recovery (membrane stripping) efficiencies during multiple adsorption-recovery cycles with synthetic and real urine. Comparing WAC with a strong acid cation exchange resin illustrated the critical role of the proton affinity of resin moieties in regulating resin regenerability and conductivity in EXS, which we distinguished from the rationale for material choice in electrodeionization. Compared to other electrochemical recovery methods using unamended wastewater as an electrolyte, EXS enabled control of electrolyte composition during recovery by separating and equalizing influent ammonium via WAC-mediated removal. This electrolyte engineering facilitated tunable EXS energy efficiency (100-300 MJ/kg N). This study informs the design of electrified, intensified systems that enable decentralized nitrogen recovery from urine.

Interaction of a Weak Acid Cation Exchange Resin (Dowex Mac 3H) with the Belousov‐Zhabotinsky Reaction and Estimation of Metal Ions

AbstractThe work pertains to the study on direct and indirect interaction of a macroporous weak acid cation exchange resin‐Dowex Mac 3H form with Belousov‐Zhabotinsky (BZ) reaction based on malonic acid‐cerium‐bromate‐sulfuric acid system. In the direct mode, the above reaction was perturbed by adding 10% (w/w) of Dowex Mac 3H at three different time intervals, i. e., before the start of induction period, during the induction period and after the commencement of oscillations. This mode of interaction was studied to investigate the effect of heterogeneity on the dynamics of BZ reaction. The indirect interaction of the resin was studied by interacting the resin individually with the optimized metal catalyst for a particular period of time after which the supernatant was used as initial reagent in the otherwise optimized BZ system. The interaction was monitored with respect to the change in oscillatory parameters before and after loading the resin with metal catalyst. The selectivity of the resin towards cerium and iron (ferroin) was studied through the said BZ reaction using potentiometry as the main technique. It was found that resin is more selective towards ferroin. The selectivity of the resin towards the various metal ions was followed by their estimation using UV‐Visible spectrophotometry. The effect of solvents on the ion exchange capacity (IEC) of the resin was also studied through the BZ reaction. Some solvents increased its IEC while others decreased it. The potentiometric results obtained were validated by spectroscopic findings and electrochemical studies.

Fluoride removal from groundwater using Zirconium Impregnated Anion Exchange Resin

Drinking water containing excess fluoride is a major health concern across the globe. The present study reports the feasibility of zirconium impregnated hybrid anion exchange resin (HAIX-Zr) for treating fluoride contaminated groundwater. The HAIX-Zr resin was prepared by impregnating ZrO2 nanoparticles on polymeric anion exchanger resin. Fluoride uptake by HAIX-Zr was quite rapid, 60% removal was obtained within 30 min. Kinetics of fluoride uptake by HAIX-Zr resin followed the pseudo-second-order kinetic model and adsorption data fitted best to Freundlich adsorption isotherm model. Maximum fluoride uptake capacity was observed as 12.0 mg/g. The defluoridation capacity of the resin decreases with increase in solution pH. The co-existing anions like chloride, phosphate, bicarbonate, nitrate, and sulphate at 100 mg/L concentration significantly affected fluoride removal and bicarbonate showed the highest interference. Continuous flow packed bed experiments were performed with real groundwater. To maintain a lower pH, weak acid cation exchange resin (INDION-236) was used before HAIX-Zr. It was observed that reducing the pH of the sample water to 4–4.5, increased the number of treated bed volumes fifteen times. Regeneration of fluoride-containing resin was done by passing 3% NaOH and 3% NaCl solution through an exhausted resin bed. The results revealed that HAIX-Zr can effectively remove fluoride from groundwater.

Superhigh adsorption of nickel from electroplating wastewater by raw and calcined electroplating sludge waste

Abstract Both the raw electroplating sludge (RES) waste and the calcined electroplating sludge (CES) were utilized to adsorb nickel from the real electroplating wastewater. The CES was obtained via calcination treatment at 500 °C, and the CES and RES were characterized by X-ray fluorescence (XRF), Fourier transform infrared spectrometer (FT-IR), X-ray powder diffraction (XRD). Adsorption isotherm results showed that the maximum adsorption capacities of Ni2+ on the CES and RES were 163.6 and 210.9 mg/g according to the Langmuir fitting, respectively. In the real nickel-containing wastewater treatment, the RES exhibited much higher adsorption capacity for Ni2+ than commonly used adsorbents including coal-based activated carbon (CAC), strong acid cation-exchange resin (D001), weak acid cation-exchange resin (D113) and amino carboxylic acid chelating resin (D463). The adsorption mechanisms of Ni2+ on the RES and CES mainly included ion exchange and surface complexation. The large amount of Ca2+ in the adsorbents played an important role in the adsorption of Ni2+ via cation exchange, and the hydroxyl and carboxyl groups on the adsorbent were also responsible for Ni2+ adsorption. Therefore, the electroplating sludge waste is an efficient adsorbent for Ni2+ removal from high concentrations of nickel-containing electroplating wastewater. This study provides a new method for the utilization of electroplating sludge as efficient adsorbents before being treated as hazardous waste, showing the feasible concept of disposal waste with waste.

Studies on active aromatic constituents from rhizomes of Sophora tonkinensis

Aromatic constituents from rhizomes of Sophora tonkinensis were purified by extensive chromatographic techniques including column chromatography over macroporous resin,MCI,silica gel,weak acid cation exchange resin,Sephadex LH-20,ODS,and semi-preparative HPLC. Twelve aromatic compounds were isolated and identified from the water aqueous extract of the rhizomes of S.tonkinensis. Their structures were elucidated as 4-( 3-hydroxypropyl) phenol( 1),( ±)-4-( 2-hydroxypropyl) phenol( 2),benzamide( 3),( ±)-3-( p-methoxyphenyl)-1,2-propanediol( 4),4-methoxybenzamide( 5),3-hydroxy-1-( 4-hydroxy-3-methoxyphenyl) propan-1-one( 6),tyrosol( 7),( ±)-2,3-dihydroxypropyl benzoate( 8),vanillin alcohol( 9),7,3'-dihydroxy-8,4'-dimethoxyisoflavone( 10),7,4'-dihydroxy-3'-methoxyisoflavone( 11),and 7,3'-dihydroxy-5'-methoxyisoflavone( 12). Compounds 1-9 were firstly isolated from the Sophora genus. Compounds 4,5,10 and 11 can remarkably protect Hep G2 cell against APAP-induced damage at the concentration of 10 μmol·L-1. Compounds 1-12 exhibited no significant activities on the assays of inhibition of LPS-induced NO production in RAW cell lines and NF-κB inhibition.

Removal of hexavalent chromium in soil by lignin-based weakly acidic cation exchange resin

Abstract The adsorption of Cr(VI) from soil onto lignin-based weakly acidic cation exchange resin (LBR) has been investigated. Lignin is a three-dimensional amorphous polymer composed of methoxylated phenylpropane units. The unique structure and chemical properties render the lignin suitable for the remediation of hexavalent chromium in the soil. Soil column leaching experiments were conducted to optimize the adsorption conditions. The effects of contact time, pH, adsorbent dosage and temperature on the adsorption of Cr(VI) onto the LBR have been investigated. Experiment data were then correlated with Freundlich and Langmuir isotherms. The Langmuir isotherm model fits the experimental data better than the Freundlich isotherm. It was found that the LBR has a high adsorption capability for Cr(VI) (3.95 mg·g−1) with a removal rate of 91.9%. Thus, LBR can serve as a good absorbent for the reduction of the concentration of Cr(VI) in soil.

Hybrid Ion Exchange Desalination (HIX-Desal) of Impaired Brackish Water Using Pressurized Carbon Dioxide (CO2) as the Source of Energy and Regenerant

Reverse osmosis and electrodialysis are truly the only water desalination processes currently in practice for the entire range of total dissolved solids (TDS) from 400–40,000 mg/L. For high recovery of 80% or more, membrane processes are energy intensive even for a feedwater with a TDS of 1000 mg/L and demand significant pretreatment to avoid precipitation and consequent membrane fouling. In this study, we present for the first time a hybrid ion exchange desalination (HAIX-Desal) process that does not require any semipermeable membrane and can desalinate lean brackish water (TDS ≤ 1500 mg/L) using CO2 as the sole source of energy and chemical regenerant. A hybrid anion exchanger with dispersed ZrO2 nanoparticles (HAIX-NanoZr) and a shell–core weak-acid cation exchange (SC-WAC) resin form the heart of the process. Carbon dioxide or CO2 at 10 atm pressure is the only chemical needed to sustain the process. In contrast to a conventional deionization plant, the anion exchanger, i.e., HAIX-NanoZr, precedes the...

SORPTION OF RHENIUM FROM SULFURIC ACID SOLUTIONS BY IMPREGNATES CONTAINING TRIALKYLAMINES

The paper studies rhenium (VII) sorption from sulfuric acid solutions by impregnates based on macroporous polymer carriers (copolymers of styrene with divinylbenzene, weak acid cation exchange resion) containing commercial trialkylamine (ТAA). The study provides equilibrium and kinetic characteristics of rhenium recovery by the impregnate based on the macroporous weakly acidic cation exchange resin (K-TAA) having the best rhenium capacity. The maximum coefficient of rhenium distribution in the K-TAA impregnate is observed in sorption from pH = 2 solutions. The rhenium sorption isotherm is described by the Langmuir equation with the K = 29±2 ml/g constant. A limited solution volume method was used to obtain the integral kinetic curves of sorption with a half-reaction time value considered to calculate the effective coefficients of rhenium diffusion in the impregnate amounted to (3,8·10–11 (295 K) and 1,3·10–10 (308 K) m2/s). Kinetic results linearized by the equations of models (pseudo-first, pseudo-second order, Elovich and inner diffusion) showed that kinetic curves with the highest correlation degree are described by the pseudo-second order equation with the 0,00056 (295 K) and 0,00059 (308 K) g·mg–1·min–1 rate constants. The apparent activation energy of rhenium sorption (39±2 kJ/mol) was calculated using the Arrhenius equation. The K-TAA impregnate was tested for rhenium sorption from the eluate obtained by rhenium desorption from the Purolite A170, weak base anion exchange resin pre-saturated with rhenium from the complex pregnant solution for leaching of products derived from poor rhenium-containing copper sulfide raw materials processed.

The effectiveness of ion exchange resins in separating uranium and thorium from rare earth elements in acidic aqueous sulfate media. Part 1. Anionic and cationic resins

Conventional ion exchange resins with different functional groups were evaluated for their potential application in separating uranium U(VI) and thorium Th(IV) from rare earth elements RE(III). The resins studied comprised strong- and weak-base anion exchange resins, and strong- and weak-acid cation exchange resins. The selectivity of these resins to adsorb U(VI) and Th(IV) in the presence of selected RE(III) was examined in sulfuric acid media of varying concentrations. It was evident that the adsorption performance of the resins was acid concentration-dependent. Most candidate resins had potentially feasible selective adsorption at or below 0.1mol/L H2SO4 (pH≥0.7). Within the group of anion exchange resins, both the strong- and weak-base resins exhibited a similar selectivity with U(VI) adsorbed in preference to RE(III). The difference between them was their adsorption of Th(IV). The weak-base resin with primary amine functional group demonstrated superior separation of Th(IV) from RE(III). For this resin, 78% of U(VI) and 68% of Th(IV) were adsorbed while RE(III) co-adsorption was <5% at 0.0005mol/L H2SO4 (pH3). In the case of the strong-acid cation exchange resins, Th(IV) and RE(III) were adsorbed in preference to U(VI), i.e., RE(III)>Th(IV)>>U(VI). The weak-acid cation exchange resins, on the other hand, displayed limited adsorption of all elements.

Preparation and Evaluation of Taste Masking Iron Suspension: Taking Advantage of Weak Cationic Exchange Resin.

The objective of this study is to use weak acid cation exchange resin to mask the taste and eliminate the teeth staining problems of ferrous sulfate liquid preparations for use in pediatrics. Amberlite IPR64 was loaded by Fe(II). Then, different suspensions of the iron-resin complex were prepared using various polymers as the suspending agents, and sorbitol as well as sucrose as sweeteners. Physical stability, rheological assessment, kinetics of Fe(II) release, and taste evaluation of suspensions were studied. The results implied that the prepared iron suspension was more stable when xanthan gum is used as the suspending agent. It was also shown that iron release in 0.7% NaCl (similar to saliva) was very negligible compared to relatively quick release in acidic medium (resembled the stomach). Overall, the volunteers confirmed that the formulations were successful in iron taste masking. The pH-dependent process of ion exchange by weak cationic resins opens an attractive approach to access a taste-masked iron suspension for infants.

Sorption of Pb (II) from battery industry wastewater using a weak acid cation exchange resin

Abstract This study investigates the removal of Pb (II) from a real battery industry wastewater by batch and column studies using a weak acid cation (WAC) resin. Batch experiments carried out under different conditions yielded optimum conditions of t = 360 min and m = 0.1 g (2 gL −1 ). The mechanism of ion exchange was studied using kinetic and thermodynamic models. The temperature had a limited effect on the diffusion kinetics. The Gibbs free energy change (ΔG°) values were negative, corresponding to a spontaneous process of Pb (II) ion sorption onto the WAC resin. The plots obtained from the first loads of the column studies show the typical “S” shape of a packed-bed system with gradual breakthrough for both flow rates. Breakthrough was reached at 360 bed volume (BV) and 83 BV for flow rates of 1 m h −1 and 3 m h −1 , respectively. Capacity losses of 77% and 87% were obtained after regeneration. WAC resins were characterized based on Fourier Transform Infrared Spectrum (FTIR), thermogravimetric analysis (TGA) and Environmental Scanning Electron Microscopy (ESEM) images before and after column studies.

Comparison between different ion exchange resins combinations for final treatment of olive mill effluent

Abstract Industrial wastewater is subjected to strict environmental legislation, thus making its adequate management a key issue. In this research work, the final purification of two-phase olive mill wastewater (OMW-2) was investigated through four ion exchange resins (a weak-acid cation exchange resin, a strong-acid cation exchange resin, a weak-base anion exchange resin and a strong-base anion exchange resin). Central composite design was used for the optimization of the IE processes. Results revealed that the only final treated OMW-2ST effluent fulfilling the legislated requirements for drinking water was the one from the combination of the strong-acid cation exchange resin and the weak-base anion exchange resin. The proposed IE process yielded up to 88% removal of these pollutants when the initial pH, operating temperature and flow rate were set to 5.1, 26.8 °C and 12.1 L h−1, respectively. Under these conditions, the achieved concentrations for all contaminants in the final stream were maintained below the maximum established limits. Finally, high treated effluent volume recovery (28 L) could be achieved in continuous mode under the optimal operating conditions found, complying with standards for reuse in the production process.

Chromatographic purification of enzymatically synthesized alkyl glucopyranosides

ABSTRACTBACKGROUNDEnzymatic synthesis and chromatographic purification of ethyl β‐D‐glucopyranoside was investigated. Ethyl β‐D‐glucopyranoside was produced from glucose and ethanol with β‐glucosidase enzyme (EC 3.2.1.21). Cation exchange resins in Ca2+ and Na+ forms were used for the purification of ethyl‐β‐D‐glucopyranoside.RESULTSGreater than 60% conversion was obtained in the synthesis. The reaction which follows the double displacement mechanism was successfully modelled with a simple kinetic model. Good separation of ethyl‐β‐D‐glucopyranoside and glucose was obtained with weak acid cation exchange resins in Na+ form. 5.5 wt% crosslinked resin performed slightly better than 8 wt% crosslinked resin. The separation is based on hydrophobic interactions. Presence of ethanol disturbs the separation and should be removed before the chromatographic step. Scale‐up of the purification step (bed volume: 0.11 L to 1.9 L) was successfully carried out to produce ethyl‐β‐D‐glucopyranoside with 99% purity. Performance of the purification process was evaluated with numerical simulations. With respect to ethyl‐β‐D‐glucopyranoside, the separation performance was found to go through a shallow maximum with increasing column loading and flow rate.CONCLUSIONAn efficient chromatographic purification method was developed for enzymatically produced ethyl‐β‐D‐glucopyranoside. This method could be utilized also in the purification of other enzymatically produced glucopyranosides. © 2015 Society of Chemical Industry

Investigation of Current Routes in Electrodeionization System Resin Beds During Chromium Removal

The elucidation and quantification of resin bed conductivity during electrodeionization processes facilitate improved cell design and performance. The aim of this project was to identify the current pathways in two types of resin beds and the various ionic forms that are present during chromium removal using a porous-plug model. The first bed consisted of an IRA-67 resin (a gelatinous weak base anion resin) prepared with hydroxyl groups, which resulted in a specific conductivity of κ¯=4.8×10−4Scm−1. When this anionic resin was conditioned with chloride groups, the value of κ¯ was 2.98×10−3Scm−1. Finally, for the mixed bed, which was comprised of IRA-67 and Dowex Mac-3 (a macroporous weak acid cation exchange resin) in a 1:1 ratio, κ¯ was increased to 0.017Scm−1. Our results showed that mixed-bed resins provide conductivities that are 35-fold higher than those of resins with hydroxyl groups and six-fold higher than those of resins with chloride groups.

Concentration of ammonium from municipal wastewater using ion exchange process

The scope of this study is concentration of ammonium from municipal wastewater using ion exchange process. Four types of ion exchange materials were tested in packed bed columns, namely strong and weak acid cation exchange resins and natural and synthetic zeolites. In total 23 runs of saturation and regeneration were done using synthetic wastewaters of different kinds and pretreated municipal wastewater. Due to its high exchange capacity and fast regeneration strong acid cation exchange resin was found to be the most suitable for ammonium concentration under condition that selectivity of ammonium removal is not of a main concern and it allows concentrating ammonium from 27 to 580mg NH4-N/L. If selective ammonium removal is required, natural zeolite should be used instead. Regeneration with 0.17M HCl and 0.17–0.51M NaCl was tested and suitability of different regenerants for different technologies of spent regenerant treatment was discussed. It was shown that electric conductivity measurements can be used for detection of breakthrough and estimation of ammonium concentration in outflow from an ion exchange column. Breakthrough curve fitting with Thomas and Adams–Bohart models was performed which gave information about the maximum exchange capacity of materials and kinetics of ion exchange.

Removal of Tetramethylammonium Hydroxide From Solution Using Ion Exchange

Ion exchange is used to remove tetramethylammonium hydroxide from an aqueous solution. Both strong acid cation (SAC) and weak acid cation (WAC) exchange resins show excellent uptake of the TMA <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> ion. The pseudo-second-order kinetic model fits the data of uptake rate well. When using an SAC exchange resin, the pH does not affect the uptake efficiency, while that of the WAC exchange resin is strongly affected by the pH. Regeneration experiments show excellent performance of resins after five cycles. The selectivity coefficient of TMA <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> over H <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> for SAC is calculated as 5.16, while for WAC, in the bulk solution, the selectivity coefficient is notably lower (6.45×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-4</sup> ). The presence of competing ions interfere with the TMA <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> uptake, of which Mg <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2+</sup> has the most notable effect. The ion exchange model is applied to obtain resin selectivity over the TMA <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> ion as well.

Adsorption Separation of 2,4-/2,6-Diaminotoluene on D151 Resin

The adsorption separation and thermodynamic behavior of 2,4-diaminotoluene and 2,6-diaminotoluene on macropore acrylic acid weak acid cation exchange resin(D151 resin),which was selected from ten resins,were investigated.The adsorption isotherms of 2,4-diaminotoluene and 2,6-diaminotoluene were measured.The result showed that the adsorption isotherm curves of 2,4-diaminotoluene and 2,6-diaminotoluene on D151 resin fitted Freundlich adsorption isotherm better than Langmuir with the correlation coefficient larger than 0.99.The study of thermodynamics showed that when the initial concentration of 2,4-diaminotoluene were 60~80 g/L within 293~313 K,the adsorption ΔH was-4.3490~-5.7558 kJ/mol,ΔG was-0.2911~-1.0346 kJ/mol,ΔS was-12.965~-16.150 J/(mol·K);and when the initial concentration of 2,6-diaminotoluene were 60~80 g/L within 293~313 K,adsorption ΔH was-2.9645~-3.6054 kJ/mol,ΔG was-0.1610~-0.6384 kJ/mol,and ΔS was-7.939~-11.005 J/(mol·K).The results show that the concentration of 2,6-diaminotoluene can be enriched from 20% to 99.93%,and 2,4-diaminotoluene can be increased from 80% to 99.42% with the dynamic adsorption separation.

A new route to functional polymers: Synthesis of functional polymer-supported esters from a weak acid ion exchange resin

Treatment of Amberlite IRC-50, a weak acid cation exchange resin containing methacrylic acid residues, with tetra-n-butylammonium hydroxide or benzyltrimethylammonium hydroxide gives the corresponding polymer-supported quaternary ammonium salts. These react smoothly, in nucleophilic substitution reactions, with a range of alkyl halides or sulfonates to give side chain esters with saturated hydrocarbon groups, with quaternary ammonium or sulfonate salt groups, with halide or alcohol groups at the terminus of spacer chains, with 1,2-diol groups, with acetylenic groups or with anthracene residues. These polymer-supported species have a variety of potential applications.