Elution Of Gold Research Articles

Enhanced and selective gold recovery from phone waste: Use of thiosulfate, dissolved oxygen, and an agriculture-based, low-cost adsorbent

Efficient methods were proposed to improve the gold recovery from printed circuit boards (PCBs) in mobile phones. Gold was selectively extracted in the form of Au(S2O3)23− using Na2S2O3-CuSO4-NH3-O2/N2 system. Under optimal conditions (temperature: 25 °C; stirring: 200 rpm; O2/N2: 3.0/0.5 L/min; time: 3 h; Na2S2O3: 160 mmol/L; CuSO4: 120 mmol/L; NH3: 0.7 mol/L (pH 9.9); solid/liquid: 4 g/L), 98% of gold was extracted. The extracted gold was adsorbed by corncob-based activated carbon (CACw), which was prepared using pyrolyzed wood vinegar. The modification of CACw with mercaptobenzothiazole (MBT), forming MBT-CACw, which displayed maximum adsorption efficiency of 49.9 mg/g. The optimal pH for adsorption was found to be 7.5 at 40 °C with 0.2 mol/L (NH4)2S2O3. The adsorption was described by the pseudo-second-order model and the Freundlich isotherm, owing to the high affinity of MBT-CACw for the sulfur donor. Copper was eluted from the loaded MBT-CACw using 0.7 mol/L (NH4)2S2O3 followed by the gold elution with 40% v/v CH3OH. The two-step elution recovered 98.7% of copper and 97.6% of gold. These findings suggest that the oxygen-assisted extraction, combined with the adsorption conducted using low-cost, agriculture-based adsorbent and selective elution, is an eco-friendly approach to efficiently recovering gold from e-waste.

Selective gold recovery from pregnant thiocyanate leach solution using ion exchange resins

Gold leaching using thiocyanate in acidic media is an alternative to cyanidation which is less toxic and can be done sequentially in one system without further preparation such as neutralization after acidic (bio)oxidation. Previous research activity in gold-thiocyanate leaching and gold recovery from thiocyanate pregnant leach solution (PLS) is limited. The current study deals with the selective recovery of gold over copper from synthetic and real thiocyanate PLS using ion exchange resins. Consequently, selective adsorption of Au(I) by ion exchange resins and selective Au(I) elution by proper eluent is proposed to obtain a high-purity Au(I) solution. First, the functionality of MTA 5011 and Amberjet 4200 resins at ambient temperature, and pH 2 for 24 h shaking at different resin mass (g) to PLS (L) ratios with synthetic PLS was compared. Then, 100 g/L MTA 5011 was chosen as the optimum resin/PLS (g/L) ratio for the highest separation with 99% gold and 12% copper extraction. Moreover, it was observed that over 24 h adsorption by 100 g/L MTA 5011, the copper extraction decreased, causing an increase in gold adsorption. Among the different reagents that were employed for gold elution, a solution of 0.01 M thiourea (TU) and 0.1 M H2SO4 was the most efficient with 70% gold and 4% copper elution. Adsorption experiments with MTA 5011 were repeated on the original thiocyanate PLS obtained after pyrite biooxidation and thiocyanate leaching using 0.2 M NaSCN and 0.01 M Fe3+. It was determined that the adsorption using 100 g/L MTA 5011 extracted ca. 99% gold and 5% copper, and for elution, a mixed solution of 0.01 M TU and 0.1 M H2SO4 recovered 99.2% gold and < 1% copper which validated the results from the synthetic PLS.

Analisis Efektivitas Alat Penukar Kalor Pelat Datar UFX-42H Terhadap Kebocoran Pelat Dalam Proses Elusi Emas

Heat exchanger is an equipment designed to exchange heat between two fluids by applying heat transfer by convection and conduction without mixing the two fluids. heat exchangers are used in the gold mining industry in the gold elution process stage with the type of alat penukar kalor pelat datar(PHE) UFX-42H to reheat the eluate (water) using glycol as the heating fluid. The PHE has a leak on the back base plate. This report aims to analyze the comparison of the effectiveness and LMTD of PHE between specification data and operational data at the time of leakage. The calculation off effectiveness requires the suhue, mass flow rate, and specific heat of the fluid. The results obtained were the effectiveness of the specification data is 0.83 and the mean of operational data is 0.71. The results of LMTD specification data is 23.91 and the mean of operational data is 28.1.

Hexaamminecobalt(III) catalyzed thiosulfate leaching of gold from a concentrate calcine and gold recovery from its pregnant leach solution via resin adsorption

Co(II) is effective in catalyzing gold thiosulfate leaching, but Co(III) has seldom been adopted directly as the catalyst. This paper examined the effect of hexaamminecobalt(III) on the thiosulfate leaching of gold from a concentrate calcine and the gold recovery via resin adsorption from the leach solution. Under the leaching solution conditions, the Co(NH3)63+/Co(NH3)x2+ (x = 4, 5) redox couple is thermodynamically formed playing the catalytic role. Experimental results verify the catalysis of Co(NH3)63+, which is better than that of Co(II) and Cu(II) in thiosulfate leaching of gold. Replacing Cu(II) by Co(NH3)63+ or Co(II), the thiosulfate consumption was significantly reduced and the complex two-stage gold elution process was simplified to a low-cost one-stage process. Compared with Co(II), Co(NH3)63+ that is already the oxidant could shorten the leaching time from 8 h to 6 h without affecting the gold extraction (~80%). In addition, the thiosulfate consumption was further lowered from 18.8 kg·t-1ore to 15.0 kg·t-1ore under the catalysis of Co(NH3)63+, which was confirmed by the X-ray photoelectron spectroscopy (XPS) analysis. Based on the thermodynamic analysis, the decrease of thiosulfate consumption may result from the formation of a lower concentration of the mixed-ligand Co(III) complexes such as Co(NH3)x(S2O3)+ (x = 4, 5). Gold recovery results suggested that, comparing Co(NH3)63+ with Co(II), the gold in the Co(NH3)63+ catalyzed leaching solution could be recovered more efficiently by resin adsorption. Therefore, Co(NH3)63+ is a catalyst more efficient than Co(II) and has promise to replace Cu(II) in the extraction and recovery of gold from its ores by thiosulfate leaching and resin adsorption.

Uptake and Recovery of Gold from Simulated Hydrometallurgical Liquors by Adsorption on Pine Bark Tannin Resin

The recovery of critical and precious metals from waste electrical and electronic equipment (WEEE) is an environmental and economic imperative. Biosorption has been considered a key technology for the selective extraction of gold from hydrometallurgical liquors obtained in the chemical leaching of e-waste. In this work, the potential of tannin resins prepared from Pinus pinaster bark to sequester and recover gold(III) from hydrochloric acid and aqua regia solutions was assessed. Equilibrium isotherms were experimentally determined and maximum adsorption capacities of 343 ± 38 and 270 ± 19 mg g−1 were found for Au uptake from HCl and HCl/HNO3 (3:1 v/v) solutions containing 1.0 mol L−1 H+. Higher levels of acidity (and chloride ligands) significantly impaired the adsorption of gold from both kinds of leaching solutions, especially in the aqua regia system, in which the adsorbent underperformed. Pseudo-first and pseudo-second order models successfully described the kinetic data. The adsorbent presented high selectivity towards gold. Actually, in simulated aqua regia WEEE liquors, Au(III) was extensively adsorbed, compared to Cu(II), Fe(III), Ni(II), Pd(II), and Zn(II). In three adsorption–desorption cycles, the adsorption capacity of the regenerated adsorbent moderately decreased (19%), although the gold elution in acidic thiourea solution had been quite limited. Future research is needed to examine more closely the elution of gold from the exhausted adsorbents. The results obtained in this work show good perspectives as regards the application of pine bark tannin resins for the selective extraction of Au from electronic waste leach liquors.

Kinetic studies of gold leaching from a gold concentrate calcine by thiosulfate with cobalt-ammonia catalysis and gold recovery by resin adsorption from its pregnant solution

The leaching of gold from a gold concentrate calcine using a novel thiosulfate leaching method that utilizes cobalt-ammonia complex as the oxidant in place of the traditional copper-ammonia catalysis was investigated. The result shows that the thiosulfate consumption can be evidently reduced without the impact on the gold extraction. The leaching kinetics of gold in thiosulfate solution with cobalt-ammonia catalysis has been studied. It was found that the reaction orders with respect to ammonia, cobalt and thiosulfate concentrations are 0.42, 0.20 and 0.34, respectively. The optimal pH value for gold leaching is 10.0, and gold can be effectively extracted at ambient temperature. The apparent activation energy is determined to be 5.68 kJ/mol, and this indicates that the gold leaching in the Co-NH3-S2O32− system is likely to be controlled by the diffusion of reactants and products through a solid layer. The XPS analysis results strongly support this hypothesis. The apparent activation energies of gold leaching in the thiosulfate-only and Cu-NH3-S2O32− systems are 30.9 kJ/mol and 8.01 kJ/mol, respectively. It can be concluded that the cobalt-ammonia catalysis for thiosulfate leaching of gold has higher catalytic efficiency than copper-ammonia catalysis. The tests for gold recovery from the pregnant solution of the Co-NH3-S2O32− system by resin adsorption were implemented, and the results demonstrated that the competitive adsorption of cobalt with gold did not occur owing to the weak affinity of the strong base anion resin for cobalt complex ions. Therefore, the elution of gold on loaded resin only needs to perform a simple one-stage process instead of the complex two-stage elution process for the Cu-NH3-S2O32− system, which will be contribute to reduce the cost of gold recovery from the pregnant solution.

Combined technology for gold desorption and ionite regeneration in the conical device

The principal technological scheme of desorption of gold and concomitant metal-impurities from the AM-2B resin phase used for the sorption processing of gold-bearing ores is considered. The proposed combined scheme, involving the use of two traditional, independent from each other methods (thiocyanate and acid-thiourea) for eluting gold, includes desorption of metal impurities from the resin with alkaline solutions of sodium thiocyanate, and gold with sulfuric acid solutions of thiourea. To shorten the duration of the process research of proposed technology was carried out the in a conical apparatus. The results of study of the elution of gold and impurity metals from anionite saturated with the following components, mg/g: Au – 2.6; Cu – 3.5; Zn – 1.3; Ni – 2.9; Co – 3.3, are given. It is shown that the main amount of impurity metals is desorbed from the resin upon its thiocyanate treatment, while the transition of gold into the eluate is negligible. The composition of the eluate in the thiocyanate treatment of saturated resin is, mg/l: Au – 1.7; Cu – 156.0; Zn – 53.0; Ni – 89.0; Co – 102.0. The subsequent treatment of the resin with sulfuric acid solutions of thiourea allows the conversion of 89.32 % of gold from the ion exchanger into the eluate. The resulting eluates containing ~113.0 mg/l gold and a small amount of impurities are target solutions for obtaining a valuable metal. The ion exchanger was regenerated by washing with water and treating with an alkaline solution of sodium to convert it to OH form, since gold sorption is carried out from alkaline cyanide solutions of heap leaching. Residual contents of components in the resin after regeneration were, mg/g: Au – 0.24; Cu – 0.23; Zn – 0.15; Ni – 0.07; Co – 1.29, which allows the successful use of the regenerated resin in the next stage of sorption.

Separation and recovery of gold from waste LED using ion exchange method

The separation and recovery of gold from waste LED using ion exchange method was investigated, employing commercial polyamine type anion exchanger, Diaion WA21J. Leaching of gold from LED terminal was successfully carried out with aqua regia at 80°C. Separation of gold from the leaching solution was then carried out by column adsorption with WA21J. The selective adsorption of gold was achieved, while adsorption of the co-existing metals in the leaching solution was suppressed. Quantitative elution of gold from WA21J was achieved with diluted thiourea solution. Elementary gold was then obtained from the eluent by simultaneous precipitation and reduction of gold with sodium borohydride with 100% purity.

RETRACTED ARTICLE: Application of Polypropylene Amine Dendrimers (POPAM)-Grafted MWCNTs Hybrid Materials as a New Sorbent for Solid-Phase Extraction and Trace Determination of Gold(III) and Palladium(II) in Food and Environmental Samples

A new method which utilizes a polypropylene amine dendrimers (POPAM)-grafted multi-walled carbon nanotubes (MWCNTs) hybrid materials as an effective sorbent in solid-phase extraction has been developed for separation and preconcentration of Au(III) and Pd(II) trace levels in food, water and soil samples. The optimum experimental conditions such as pH, flow rates, type, concentration, and volume of the eluent for elution of gold and palladium ions, breakthrough volume, and effect of potentially interfering ions on separation and determination of these noble metals were investigated. The extraction recoveries for the mentioned noble metals were greater than 98 % and the limits of detection were 0.08 and 0.12 ng mL−1 for gold and palladium, respectively. The relative standard deviations of the method were less than 4 % for eight separate column experiments for determination of 5.0 μg of gold and palladium ions. The adsorption capacity of the modified MWCNT was 92 mg g−1 for gold and 74 mg g−1 for palladium on POPAM-grafted MWCNTs. Validation of the suggested method was performed by analyzing certified reference materials. Finally, the proposed method was applied for determination of gold(III) and palladium(II) in real samples, including fish, shrimp, water, and soil.

Ion exchange recovery of gold from iodine–iodide solutions

The recovery of gold from iodine–iodide solutions using strong base anion exchange resin has been investigated. The gold iodide complex can be effectively loaded on the resin provided the resin is not heavily loaded with triiodide. The loading of triiodide is found to be extremely strong due to the dissociation of the loaded triiodide to iodide and iodine, the latter being deposited on the resin by physiosorption thereby fouling the surface. This may be potentially detrimental to the gold recovery process but can be overcome by pre-reduction to remove most of the triiodide before loading. To strip the iodine from the resin it requires a reductive elution process. A sodium chloride based eluant solution containing sulfite is found to be highly effective for the elution of both gold and iodine.

Thermal desorption of mercury from gold-loaded granule activated carbon and its effect on gold elution

The thermal desorption technique has been explored experimentally to remove mercury from the gold-loaded granule activated carbon (GAC) co-adsorbed during heap leaching of gold ores bearing mercury. The effects of treatment temperature, retention time and flow rate of steam used as purge gas on residual mercury levels were investigated. Characterization techniques such as N2 adsorption–desorption, X-ray powder diffraction and X-ray photoelectron spectroscopy, were employed to understand how thermal treatment affects the gold elution in a caustic cyanide-free eluant from the treated GAC. The results showed that mercury desorption was strongly affected by the treatment temperature and steam flow rate. Treatment for 3h at 550°C under steam atmosphere with 0.4m3/h flow rate was allowed to remove more than 99.78% mercury and the content of residual mercury in the treated GAC was decreased to 0.035g/kg, likely reaching the thresh level of mercury extraction during gold elution in a caustic cyanide eluant. Meanwhile, activated carbon was partially regenerated, with only 4.06% weight loss of carbon, mainly due to microporosity recovery. However, it was observed that the thermal process would have heavily influenced elution of gold from the treated activated carbon in a caustic eluant without sodium cyanide. This phenomenon has been attributed primarily to the change of chemical state of gold species and accumulation of highly dispersed gold species and even formation of more stable gold nano-particles caused by a combination of promotion of high temperature and steam oxidation. The elution of gold from the treated sample could be improved through introduction of NaCN into the caustic eluant. However only 83.84% of gold was eluted, probably because the elution time was insufficient.

Selective elution of gold, silver and mercury cyanide from activated carbon

A high-pressure laboratory elution rig was commissioned to simulate industrial Zadra and AARL elution conditions for the stripping of gold, silver and mercury from loaded activated carbon. It was found that cyanide was essential for the efficient elution of both mercury and silver, while gold was found to elute most effectively in hot, low-ionic strength solutions. Therefore, the standard AARL-type elution, which implements a cyanide soak and water elution, results in a lower recovery of mercury and silver from the carbon. No single set of conditions was found whereby gold, silver and mercury can all be effectively eluted in a single step. However, sequential elution conditions can efficiently recover all metals and provide a potential approach for separating these metals.

Adsorption of gold(III) from waste rinse water of semiconductor manufacturing industries using Amberlite XAD-7HP resin

Advanced hydrometallurgical separation processes are gaining significant importance for the recovery of gold from the aqueous solutions viz. leach liquor of waste electronics, plating material solutions, and waste wash water from electronic industries. In the present investigation, gold adsorption from the waste rinse water of semiconductor manufacturing industries is reported using Amberlite XAD-7HP. For experimental purposes, chloride waste rinse water that contained primarily Au (281 mg/ L) with trace amounts of Cu, Ni, Zn, Sn etc was used. Batch studies were carried out to optimize various process parameters, including contact time, acidity of solution, and resin dosage for the adsorption of gold from the above waste effluent. Adsorption of 92.25% gold was found from the waste solution within a contact time of 30 minutes at an aqueous to resin (A/R) ratio of 25 mL/g and an equilibrium pH of 0.63. In optimal conditions, the loading capacity of resin for gold was observed to be 58.82 mg of gold/g of resin. The gold adsorption phenomena were confirmed by the comparative FT-IR spectroscopic characterization studies of fresh resin and gold loaded resin. Elution tests were carried out for the elution of gold from the gold loaded resin using various ratio mixtures of acetone and 1.0 M HCl. An elution efficiency of 96.96% gold was achieved at an acetone-to-acid ratio of 9. In this condition, gold-enriched solution containing 7,240 mg gold/ L was obtained. The maximum elution of gold was found to be 99.33% using pure acetone in a contact time of 30 minutes. The data obtained will be useful to simulate the continuous gold adsorption process within a column.

Recovery of zero-valent gold from cyanide solution by a combined method of biosorption and incineration

A new combined way of biosorption and incineration is presented for the recovery of gold from gold-cyanide solutions. Decarboxylated biosorbent (DCB) was prepared by removing interfering carboxyl groups from the surface of inactive Corynebacterium glutamicum. The recovery of gold from the exhausted biosorbents was performed using elution or incineration. The maximum gold(I) uptakes were obtained as 50.19 and 86.16mg/g for the raw biomass and DCB, respectively. The biosorption performance of DCB indicated that interfering carboxyl groups were successfully removed. The recovery efficiency of ionic gold through elution and purity of metallic gold by means of incineration were over 93% and as high as 61.89%, respectively. The result of XPS analysis indicated that the gold(I) was able to be reduced into zero-valent gold during incineration. It was noted that the combined method of biosorption and incineration could be effective for concentration and recovery of gold from the cyanide solutions.

A proposed mechanism for nitrate and thiocyanate elution of strong-base ion exchange resins loaded with copper and gold cyanocomplexes

The use of ion exchange resins for the recovery of gold cyanide and other base metal cyanocomplexes has been hindered by poor elution, among other factors. To overcome this drawback, saline solutions have been proposed as an eluant for the loaded cyanocomplexes, with nitrate and thiocyanate being the most promising. In the present work, the elution of gold- and copper-cyanocomplexes from polyacrylic- and polystyrene-based resins at 50 °C was studied. The results showed that copper cyanide was easily eluted from polyacrylic- and polystyrene-based ion exchange resins using either 1 mol/L SCN − or NO 3 - . However, there was poor elution of the gold cyanide complex from the polystyrene-based resins using nitrate solutions, reflecting the higher affinity that gold cyanide presents for the latter. Conversely, gold elution reached 90% using thiocyanate. Therefore, the separation of gold and copper is possible using polystyrene resins, eluting first with nitrate and then with thiocyanate. Raman spectra have shown the presence of gold and also copper complexes in the resin beads, as well as in the eluate produced during elution of both the resins, suggesting that elution takes place by an ion exchange mechanism. The better performance observed using thiocyanate, as compared to nitrate, is discussed, based on the features of both ions.

Recuperación de oro desde un medio amoniaco-tiosulfato con resina de intercambio iónico Amberlite IRA-410

The adsorption and elution of gold in thiosulfate-ammonia media were studied at laboratory level using the Amberlite IRA-410 ionic exchange resin. Tests were carried out in a stirred reactor, maintaining constant temperature (25 oC), with a volume of solution/mass of resin ratio of 833,3 ml/g and during 3 h. The variables tested were the following: pH (911), thiosulfate concentration (0-0,5 M), ammonia concentration (0-0,5 M) and selectivity in the presence of cupric ion. The obtained results indicate that gold adsorption was quick; the presence of thiosulfate decreased strongly the adsorption; and the presence of ammonia did not affect the adsorption mostly. The copper was in a certain measure a competitor of the gold, but its biggest negative effect was that acted as catalyst of the oxidizing reaction of thiosulfate (S 2 O 3 ) to tetrathionate (S 4 O 6 2‐ ) and trithionate (S 3 O 6 2‐ ), which can cause a partial elution of gold during the load stage. Also, the behavior of ClO ‐ 4 , SO 3 and ClO ‐ as eluents was studied in both gold and copper elution. These tests were also carried out in a stirred reactor, to constant temperature (25 oC), with a volume of aqueous solution/mass of resin ratio of 200 ml/g and for 3 h. Results demonstrated that the copper was eluted more quickly that the gold in all the cases.

Thiosulphate as an alternative to cyanide for gold processing – issues and impediments

Thiosulphate is an attractive alternative reagent to cyanide for processing gold ores. It is relatively cheap and non-toxic, forms relatively strong gold and silver complexes, and readily leaches gold ores in ammoniacal solutions, catalysed by Cu(II). It is particularly suited to carbonaceous ores where the recovery of gold by cyanide is poor. However, research over the past 20 years has identified a number of issues and impediments that must be understood or overcome before an overall process can be demonstrated as practical and economic for typical oxidised gold ores. This paper reviews the current understanding of thiosulphate chemistry and mechanism of gold dissolution, and discusses the stability of thiosulphate and polythionates. It then reviews the results of leaching various gold ores that have been reported in the literature, discusses gold recovery options, and considers environmental and toxicity issues. Some of the issues that require further research include decreasing the oxidation of thiosulphate by Cu(II) or other oxidants, increasing the extraction of gold compared to cyanide, and understanding the variation in gold recovery between ores. More work is also required to minimise the effect of polythionates on gold recovery using resins or alternative absorbents, to improve the elution of copper and gold from resins, and to recycle or minimise the concentration of reagents.

Adsorption behavior of noble metal ions (Au, Ag, Pd) on nanometer-size titanium dioxide with ICP-AES.

The adsorption behavior of gold (Au), silver (Ag) and palladium (Pd) on nanometer-size titanium dioxide (NSTD) at low concentrations was studied using inductively coupled plasma atomic emission spectrometry (ICP-AES). A preconcentration procedure of the analytes was carried out using NSTD as a solid-phase extractant before their determination by ICP-AES. The optimum conditions for adsorption were studied in detail, and under the condition that Au, Ag and Pd ions could be adsorbed and recovered quantitatively. The static adsorption capacities of Au, Ag and Pd on NSTD were 22.63, 14.06 and 11.82 mg/g, respectively. For the elution of gold, silver and palladium, a mixture of 5% thiourea solution and 3 mol L(-1) HNO3 was used. The parameters tested included: pH conditions, contact time of the analytes with NSTD, flow rate, adsorption capacity and sorption kinetics. According to the definition of IUPAC, the detection limits (3sigma) of this method for Au, Ag and Pd with an enrichment factor of 50 were (0.016), (0.006) and (0.012) microg mL(-1), respectively, the relative standard deviations (RSD) were 8.7%, 4.5% and 7.4%, respectively (n = 6). Some geological samples were determined with satisfactory results.

The recovery of gold from ammoniacal thiosulfate solutions containing copper using ion exchange resin columns

The loading of gold and copper, both individually and simultaneously, from thiosulfate solutions onto ion exchange resin columns and the subsequent elution of these species have been investigated. In the presence of copper, effective loading with good selectivity for gold can be achieved at pH 11, which balances the stability of the solution and minimizes the formation of poisoning polythionates. The loaded metals can be eluted with high efficiencies using a number of composite eluant solutions. These include sodium tetrathionate stabilized with sodium sulfite and ammonium thiosulfate (ATS), sodium sulfite coupled with ammonia, and sodium chloride with the addition of ATS. The addition of thiosulfate to the eluant seems to have a negative effect on the gold elution efficiency and should be avoided wherever it is possible. Of all the three eluants investigated, the sodium sulfite/ammonia combination is found to be the most efficient, but the sodium chloride/ATS combination is likely the most economical.

Sorption of aurocyanide and tetrachloroaurate onto resin with guanidine ligand—an XPS approach

The guanidine ligand attached to vinylbenzyl chloride matrix as well as its sorption ability to tetrachloroaurate and dicyanoaurate ions were investigated upon using X-ray photoelectron spectroscopy. The form of metallic gold, Au(0), was not observed on gold loaded resin surface when solutions of tetrachloroaurate or potassium dicyanoaurate were used. Complete elution of gold was achieved for both regeneration media: thiourea solution and mixture of sodium hydroxide and benzoate. The results demonstrate that XPS can also be a powerful technique for the analysis of the oxidation state of sorbed metal and can be a suitable method for the confirmation of functional groups incorporated in the polymer.