Sorbent Particles Research Articles

In-Flight Mercury Removal and Cobenefit of SO2 and NO Reduction by NH4Br Impregnated Activated Carbon Injection in an Entrained Flow Reactor

The in-flight mercury removal performance of ammonium bromide impregnated activated carbon (NH4Br-AC) was evaluated in an entrained flow reactor (EFR) under simulated flue gas. The factors that affect in-flight mercury removal efficiency were explored. The optimum operating parameters were selected to be verified in the EFR under real flue gas, which was derived from the anthracite combustion in a 6 kW circulating fluidized bed (CFB) combustor. The coeffect of NH4Br-AC injection on SO2 and NO emission was also investigated. The results show that the in-flight mercury removal rate of raw activated carbon (R-AC) is significantly improved by the NH4Br modification. Greater sorbent feed rate, longer sorbent residence time, and smaller sorbent particle size are beneficial for improving the in-flight mercury removal rate. In the anthracite combustion flue gas, with the increase of sorbent residence time from 0.59 to 1.79 s, the in-flight mercury removal rate of NH4Br-AC increases from 70.7% to 90.5%. Although the physisorption strengths of SO2 and NO are greater than that of gas-phase mercury, the increase of the Br group on the NH4Br-AC surface improves the mercury adsorption affinity. The reduction rates of SO2 and NO reach 30.6% and 38%, respectively, but the SO3 concentration in the flue gas increases 116% compared to the original emission concentration. The reduction of SO2 and NO in the flue gas is attributed to the chemisorption on the NH4Br-AC surface and the oxidation by the injected O2 existing in the sorbent carrier gas, which promotes more SO3 and NO2 generation in flue gas.

Numerical study of pulverized coal-fired utility boiler over a wide range of operating conditions for in-furnace SO2/NOx reduction

Important tasks during pulverized coal-fired utility boiler exploitation are efficient utilization of variable quality fuels, operation in a wide range of loads and emission reduction of pollutants, like oxides of nitrogen and sulfur. Combustion process modifications for NOx control and the furnace sorbent injection for SO2 control are cost-effective clean coal technologies. For optimization of boiler operation mathematical prediction is regularly used and the need for modeling is most apparent in complex flows, such as turbulent reactive flows in coal-fired furnaces. Simulation of processes in a utility boiler pulverized lignite-fired furnace was performed by an in-house developed numerical code. The code is a promising numerical tool to be used also by engineering staff dealing with the process analysis in boiler units. A broad range of operating conditions was examined, such as different boiler loads, fuel and preheated air distribution over the burners and the burner tiers, grinding fineness of coal, cold air ingress and recirculation of flue gases from the boiler exit. Ash deposit on the screen walls, affecting the heat exchange inside the furnace, was considered as well. Simulations suggested optimal combustion modifications providing NOx emission reduction, with the flame geometry improvement, as well. SO2 reduction by injection of pulverized Ca-based sorbents into the furnace was also analyzed. Models of the sorbent particle calcination, sintering and sulfation reactions were optimized and implemented within the numerical code. Numerical experiments considered different operation parameters, such as Ca/S molar ratio, sorbent particle size and dispersion, local gas temperature in different injection zones and the particle residence time. A proper distribution of finely ground sorbent particles could be expected to provide an efficient absorption of SO2. With respect to the boiler thermal calculations, the facility should be controlled within narrow limits of operation parameters due to often contradictory requirements with respect to emission reduction and the boiler unit efficiency with safe operation of superheaters. A number of influencing parameters require such a complex approach to evaluate alternative solutions and enable efficient, low emission and flexible operation of power plant boiler units.

A fast and innovative microextraction technique, μSPEed, followed by ultrahigh performance liquid chromatography for the analysis of phenolic compounds in teas

The objective of this study was to evaluate the efficiency of a promising solid phase microextraction technique, μSPEed, in the analysis of selected phenolic compounds from teas by ultrahigh performance liquid chromatography with photodiode array detection (μSPEed/UHPLC-PDA). The innovative μSPEed configuration uses 3-μm sorbent particles tightly packed in a disposable needle equipped with a pressure-driven valve to withdraw samples in a single direction. The system was operated by the electronic pipette eVol® and different parameters influencing the extraction efficiency, as the nature of sorbent, pH, loading and elution conditions, and solvents were optimized. The best extracting conditions were obtained by loading twice 100μL of tea samples through the PS/DVB-RP sorbent and eluting with 50μL of acidified MeOH 95%. The following chromatographic separation was carried out in an Acquity C18 BEH capillary column using a gradient of 0.1% FA and acetonitrile. The optimized μSPEed/UHPLC-PDA methodology is selective and specific and was properly validated for 8 phenolic compounds widely reported in different teas. Overall, an excellent analytical performance was obtained in the 0.2–20μg/L linear dynamic range (LDR), with very low limits of detection (LODs) and quantification (LOQs), ranging between 3.5–16.8ng/mL and 10.6–50.6ng/mL, respectively, high recoveries (89.3–103.3%), good precision (RSD<5%) and negligible matrix effect. The methodology was used to assess the target polyphenols concentration in several tea samples. Rutin and quercetin-3-glucoside were the most abundant phenolics in all tea samples analysed and, with exception of naringenin and cinnamic acid, which are present in high amounts in the investigated citric teas, remain phenolic compounds are present in trace levels.

Uranium (VI) Sorption Using Functionalized-Chitosan Magnetic Nanobased Particles

Hybrid materials were synthesized by chemical grafting of different compounds (diethylenetriamine DETA, cysteine, alanine and serine) on chitosan/magnetite nanoparticles. The sorbents were characterized by TEM, XRD and FTIR analysis and vibrating sample magnetometry (VSM) before being tested for uranium sorption. The nanometric size of sorbent particles reduces the impact of diffusion resistance and uptake kinetics are quite fast. Sorption isotherms are modeled by the Langmuir equation. The sorption is spontaneous and exothermic. Uranium is desorbed using acidic thiourea and the sorbent can be recycled for at least 4/5 cycles.

Ion Dynamics in Li2CO3 Studied by Solid-State NMR and First-Principles Calculations

Novel lithium-based materials for carbon capture and storage (CCS) applications have emerged as a promising class of materials for use in CO2 looping, where the material reacts reversibly with CO2 to form Li2CO3, among other phases depending on the parent phase. Much work has been done to try and understand the origin of the continued reactivity of the process even after a layer of Li2CO3 has covered the sorbent particles. In this work, we have studied the lithium and oxygen ion dynamics in Li2CO3 over the temperature range of 293–973 K in order to elucidate the link between dynamics and reactivity in this system. We have used a combination of powder X-ray diffraction, solid-state NMR spectroscopy, and theoretical calculations to chart the temperature dependence of both structural changes and ion dynamics in the sample. These methods together allowed us to determine the activation energy for both lithium ion hopping processes and carbonate ion rotations in Li2CO3. Importantly, we have shown that these pro...

A detailed study on adsorption isotherms of Hg(II) removal from aqueous solutions using nanostructured sorbent ZnCl2-MCM-41

A comparison between linear and non-linear regression methods to determine the optimum isotherm was done by applying these models to the experimental equilibrium data of Hg(II) sorption using new nanostructured sorbent ZnCl2–MCM-41. The best-fitting linear isotherm was selected based on the highest R2 value obtained. In the case of non-linear methods, different error functions were employed to determine the best-fitting model. Langmuir isotherm was found to be the best-fitting model in both linear and non-linear cases, which implies a monolayer adsorption of Hg(II) onto a homogeneous surface of ZnCl2–MCM-41. Scanning electron microscopic images verified the spherical morphology of the sorbent particles. The adsorption capacities of Hg(II) onto CaCl2–MCM-41, CuCl2–MCM-41, and MgCl2–MCM-41 were demonstrated to be less than those of ZnCl2–MCM-41. Lastly, Hg(II) recovery of up to 75% was obtained by utilizing 0.1 M HNO3 solution.

Modeling and experimental studies of in-duct mercury capture by activated carbon injection in an entrained flow reactor

A new mathematical model was proposed to predict in-duct mercury capture efficiency and determine the effect of sorbent properties on mercury capture by sorbent injection. The model was based on external film mass transfer assumption and included mass balance and adsorption isotherm. Adsorption parameters of the sorbent were determined by the fixed-bed mercury adsorption experiments and other modeling parameters were estimated from literatures. The model verification was conducted by comparing with the experimental results of mercury capture by raw and bromine modified activated carbon (R-AC and AC-Br) injection in an entrained flow reactor. The results show that there is a reasonable agreement between the modeling prediction and the experimental results, which demonstrates that this model can provide a rational prediction results and be used to estimate sorbent consumption cost. In both the experimental and modeling cases, mercury capture efficiencies are improved with smaller sorbent particle size, longer sorbent residence time and larger sorbent concentration. The in-duct mercury capture rate of AC-Br was improved significantly compared to that of R-AC. The simulation of in-duct mercury capture by sorbent injection demands taking into account the additional mercury capture by deposited activated carbon on the duct wall. The model parameters, including sorbent concentration, particle size, equilibrium constant K, external film mass transfer coefficient and residence time have important effects on the in-duct mercury capture rate by sorbent injection.

Characterization of kinetic limitations to atmospheric CO2 capture by solid sorbent

AbstractScrubbing CO2 directly from the ambient air (air capture) by sorbent is an emerging technology to address climate change due to anthropic emission of greenhouse gases. A good understanding of thermodynamics and reaction kinetics under ultra‐low CO2 concentration and variable humidity is fundamental to the design of economic air capture. In this study, the adsorption kinetics of a novel moisture swing process for air capture is characterized. The variation of humidity alters not only the adsorption equilibrium but also the adsorption kinetics, due to a water involved chemical reaction. A heterogeneously structured sorbent sheet with strong based ion exchange resin inside as active constituent is employed to capture the atmospheric CO2 under different humidity. Traditional shrinking core model (SCM) is modified to reveal the mass transfer resistance inside of the sorbent for CO2 adsorption under ultra‐low CO2 concentration. The modified SCM reveals that, at most cases, the adsorption kinetics is controlled by diffusion inside of the sorbent particle. A transition from physical diffusion controlled kinetics to chemical reaction controlled kinetics is observed as humidity increases. Further kinetic analysis suggests that, among the optimization technologies such as seeking functional group with faster chemical reaction or fabricating thinner support layer, preparing sorbent particle with smaller size or higher porosity should have much more potential on the enhancement of air capture kinetics. © 2015 Society of Chemical Industry and John Wiley &amp; Sons, Ltd

Preparation and kinetics of a heterogeneous sorbent for CO2 capture from the atmosphere

Capturing CO2 directly from the atmosphere using chemicals (air capture) is a strategic approach to mitigate global warming. Before the widespread deployment of air capture, technical challenges, such as the poor kinetics under ultra-low CO2 concentrations, must be addressed. This work aims to characterize and optimize the mass transfer process of a novel moisture swing adsorption method for air capture. The phase inversion technique is employed to fabricate a heterogeneous structured sorbent. The modified shrinking core model and a revolving bed reactor are developed to evaluate the adsorption kinetics. The sorbents exhibit significant diffusion-controlled kinetics under most of the measurement conditions. The effects of ambient conditions on kinetics, such as temperature and relative humidity, were investigated. The diffusion and chemical reaction rate drop sharply as the temperature decreases from 20 to 0°C. The relative humidity shows a more obvious effect on the chemical reaction than on the physical diffusion process due to the mechanisms of hydration water involved in the chemical reaction. On the other hand, reducing the size of the sorbent particles to several micrometers could effectively avoid the substantial reduction in the adsorption rate under lower temperatures. Using the determined kinetic parameters, suggestions for kinetics optimization are proposed for air capture under different weather conditions.

A model of integrated calcium looping for CO2 capture and concentrated solar power

Calcium Looping (CaL) is a promising post-combustion CO2 capture and storage technique. Thermal input to the calciner, which is needed to sustain the endothermicity of sorbent regeneration, is usually accomplished via oxy-combustion of an auxiliary fuel. The idea behind the present study is to couple CaL with a Concentrated Solar Power (CSP) system, so that all the thermal energy required in the calciner is supplied by a renewable source. The integration of a CaL cycle with a CSP system offers several potential technical, economical and environmental advantages, but must cope with the inherently unsteady nature of incident solar power. The cyclic character of incident solar power as compared with steady CaL operation could be managed in different ways. In the present study a simple scheme of integrated CaL-CSP process is suggested, based on storage of the excess incident power during the daytime as calcined sorbent, which is eventually utilized in the CaL loop during the nighttime. A preliminary assessment of the performance of this integrated scheme is accomplished by means of model computations. The model is based on a population balance model on sorbent particles, which takes into account the cyclic operation of the system. The parameters of the solar field and the influence of the main operating parameters (sorbent residence time, sorbent/CO2 inlet molar ratio, fluidization velocity) on carbonation degree and efficiency, on sorbent loss by elutriation, on thermal power demand at the calciner and on thermal power produced in the carbonator have been assessed.

The effects of carbon-in-ash on mercury capture from flue gas

&lt;p class="emsd"&gt;&lt;span lang="EN-GB"&gt;Mercury, although only a trace element in coal, is an important pollutant because coal burning is increasing around the world for manufacturing and energy production. In addition, coal-fired plants are the largest anthropogenic source of mercury emission to the environment. Mercury capture mostly occurs under heterogeneous conditions between sorbent particles and gaseous mercury, and this study is mainly devoted to understanding the role of carbon-in-ash on mercury capture from flue gas. Coal flyash samples are characterized by loss-on-ignition (LOI) carbon content, surface area (BET) tests, and scanning electron microscopy (SEM) morphology. Flyash sorbents are injected using an in-flight configuration and then mercury concentration is measured by Hg continuous emission monitoring system (CEMS). The unburned carbon in ash is found to be one main factor for capturing mercury. In addition, mercury capture increases when flyash samples have more surface area. Carbon in ash is also positively correlated with surface area within coal rank. This suggests that unburned carbon plays a formative or structural role in surface area increase on flyash. However, mercury uptake is shown to be relatively low when using flyash from high rank coal such as anthracite because of the small surface area coming from its non-porous structure. Therefore, when flyash is used as a sorbent for mercury capture, quantitative surface area should be compared and coal rank also should be considered. Carbon content in ash as mercury capture sorbents is a good indicator for mercury capture, but its surface area should also be considered for predicting mercury uptake.&lt;/span&gt;&lt;/p&gt;

Self-Activation Mechanism Investigations on Large K2CO3-Doped Li4SiO4 Sorbent Particles

This work investigated the self-activation behavior of large K2CO3-doped Li4SiO4 sorbent particles. In this self-activation mechanism, the sorption ability increased as the number of cycles increased. After the sorption–desorption cycles occurred, the sorption ability of the K2CO3-doped Li4SiO4 sorbent was remarkably enhanced from approximately 2.0 mmol CO2/g sorbent to approximately 5.0 mmol CO2/g sorbent at 565 °C in 10 vol % CO2 atmosphere. The fresh and used sorbents were then characterized through N2 adsorption and SEM methods. Results showed that the average pore size increased from 7 to 32 nm and the surface microstructure changed from dense to porous, because the molten eutectic mixture formed by Li2CO3 and Li2SiO3 can facilitate CO2 diffusion. The formed CO2 diffusion channel can provide more CO2 accessibility; this channel can also reduce the CO2 diffusion resistance through the product layer. Therefore, the sorption ability of the sorbent is enhanced. Meanwhile, the effects of the self-activation temperature were also investigated and the results revealed that the optimal self-activation temperature is 615 °C. Furthermore, under critical conditions, the self-activated sorbent performed more efficiently than the fresh sample. At 450 °C under 10 vol % CO2 atmosphere, the sorption capacity of the self-activated sorbent was approximately 20 times higher than that of the fresh sample. Finally, a pore–core model was also proposed to illustrate the K2CO3-doped Li4SiO4 self-activation mechanism.

Carbon-containing sorbents for removing volatile radioactive iodine compounds from the water vapor-air medium

The sorption of CH3 131I and 131I2 from a water vapor-gas medium onto various grades of activated carbon was studied. All the sorbents tested exhibit high ability to take up 131I2. The 131I2 uptake exceeds 99.95% at 60°C and contact time of the gas phase with the sorbent τ = 0.5–0.7 s. The ability of the sorbents based on activated carbon to take up CH3 131I strongly depends on the sorbent particle size. High ability to take up CH3 131I from a water vapor-air flow is preserved only for cylindrical particles 1.0 mm in diameter and 1.0–2.0 mm long. Activated anthracite, like activated carbon with cylindrical particles 3.5 mm in diameter and 3.0–9.0 mm long, exhibits low performance in CH3 131I uptake. The degree of localization of CH3 131I does not exceed 40% at 60°C and τ = 0.5–0.7 s.

YREE scavenging in seawater: A new look at an old model

In the ocean, yttrium and the rare earth elements (YREEs) show nutrient-like vertical profiles. Since the YREEs have no manifest biological function, their removal from solution (scavenging) is probably caused by sorption on particles rather than active microbial uptake, yet the exact nature of these particles is uncertain. An existing theoretical model describes scavenging as an equilibrium between complexation with dissolved inorganic ligands and with functional groups on particle surfaces. This model was able to predict input-normalized (i.e., shale-normalized) YREE abundance patterns in seawater without requiring poorly known parameters like particle concentrations or the site densities of functional groups. Employing well-established stabilities of inorganic YREE complexes, while assuming that the sorbent particles are organic with functional groups represented by a mixture of simple monocarboxylic acids, it reproduced some key features of seawater YREE patterns, specifically the characteristic increase of shale-normalized abundance with atomic number and distinctive anomalies of certain trivalent REEs (La and Gd). The familiar negative Ce anomaly of seawater, however, is due to redox reactions that were not explicitly accounted for.In this study, we refined calculations of YREE solution speciation by adding complexation with desferrioxamine B to gauge the influence of strong organic ligands prevalent near the ocean surface. The scavenging model was then inverted by subtracting high-quality YREE abundance patterns, reported for the open ocean, from this solution speciation to yield an average pattern of relative YREE affinities for the sorbent particles. The resulting affinity pattern is compared with patterns of distribution coefficients, derived from laboratory experiments, for YREE sorption on relevant solid phases including hydrated Fe and Mn oxides (HFO/HMO), calcite, and the green macroalga Ulva lactuca as a substitute for marine organic matter. For deep seawater, the best agreement is observed with HMO, which may thus be the dominant carrier of YREEs to the sediment. Since Ce is catalytically oxidized on manganese oxide surfaces, this could have implications for the evolution of the Ce anomaly. Direct comparisons of distribution coefficient patterns with YREE analyses of suspended particles from the Atlantic Ocean also favor HMO, but this may be dictated in one case by the use of a selective leaching method. For shallow seawater, particularly in the Atlantic Ocean, the best agreement is observed with U. lactuca and calcite, although the latter is offset by the low YREE contents of this biogenic mineral. Matches with HFO are generally less convincing. The aforementioned mixture of simple monocarboxylic acids is not a good proxy for the sorptive properties of marine organic matter.

Diethylenetriamine-functionalized chitosan magnetic nano-based particles for the sorption of rare earth metal ions [Nd(III), Dy(III) and Yb(III)

The recovery of three rare earth (RE) metals ions [Yb(III), Dy(III) and Nd(III), belonging to heavy, mild and light REs, respectively] was investigated using hybrid chitosan-magnetic nano-based particles functionalized by diethylenetriamine (DETA). The effect of pH on sorption performance was analyzed: the optimum initial pH value was found close to 5 (equilibrium pH value close to 6.5). The nanometric size of sorbent particles (30–50 nm) minimized the contribution of resistance to intraparticle diffusion on the control of uptake kinetics, which is efficiently modeled using the pseudo-second order rate equation: under selected experimental conditions the contact time required for reaching equilibrium was less than 1 h. Sorption isotherms were efficiently modeled using the Langmuir equation: maximum sorption capacities reached about 50 mg metal g−1, regardless of the RE. The temperature had a very limited effect on sorption capacity (in the range 300–320 K). The thermodynamic parameters were determined: the sorption was endothermic (positive values of ΔH°), spontaneous (negative values of ΔG°) and contributed to increasing the disorder of the system (positive values of ΔS°). The three REs have similar sorption properties on DETA-functionalized chitosan magnetic nano-based particles: the selective separation of these elements seems to be difficult. The sorbed metal ions can be removed from loaded sorbents using thiourea, and the sorbent can be recycled for at least five sorption/desorption cycles with a limited loss in sorption performance (by less than 6 %). The saturation magnetization was close to 20 emu g−1; this means that nano-based superparamagnetic particles can be readily recovered by an external magnetic field, making the processing of these materials easy.

Effect of surface radiative properties of a CO(2) sorbent particle on its interactions with high-flux solar irradiation.

A thermal transport phenomena model for the decomposition of a CO₂ sorbent particle under concentrated solar irradiation is used to evaluate four approximate engineering models for the surface radiative properties of the particle. The radiative property models are formulated by considering the solid-phase to be opaque or semi-transparent and the size of the surface features to be either smaller or larger than the incident irradiation wavelength. Time to complete decomposition of the particle and maximum surface temperature in simulations employing the four models differ by approximately 2% and 0.5%, respectively.

Direct blue 71 dye removal probing by potato peel-based sorbent: applications of artificial intelligent systems

In this study, the direct blue 71 (DB71) removal efficiency from aqueous solutions by potato peel-based sorbent was examined. Furthermore, influences of five operating parameters including initial pH, sorbent particle size, dose of sorbent, initial dye concentration, and contact time were studied. The Taguchi approach was used to design of experiments. The experiments were performed in a 200-mL batch reactor. Maximum DR% was 90% (448 mg/gr sorption capacity) in initial pH 3, sorbent particle size 225 μm, dose of sorbent 20 g/L, initial dye concentration 100 mg/L, and contact time 10 min. Also, maximum sorption capacity was 1,704 mg/g (85% dye removal) in initial pH 3, sorbent particle size 575 μm, dose of sorbent 5 g/L, initial dye concentration 100 mg/L, and contact time 150 min. The results revealed that the potato peel-based sorbent is promising for the sorption of DB71. After collecting data-set of DR%, artificial neural network (ANN) and genetic algorithm were applied for modeling and optimization of sorption efficiency. The R2 and root mean square error of the test set were 0.99 and 3.4 for ANN model.

Thermal transport model of a sorbent particle undergoing calcination–carbonation cycling

A numerical model coupling transient radiative, convective, and conductive heat transfer, mass transfer, and chemical kinetics of heterogeneous solid–gas reactions has been developed for a semitransparent, nonuniform, and nonisothermal particle undergoing cyclic thermochemical transformations. The calcination–carbonation reaction pair for calcium oxide looping is selected as the model cycle because of its suitability for solar‐driven carbon dioxide capture. The analyzed system is a single, porous particle undergoing thermochemical cycling in an idealized, reactor‐like environment. The model is used to investigate two cases distinguished by the length of the calcination and carbonation periods. The calcination–carbonation process for a single particle is shown to become periodic after three cycles. © 2015 American Institute of Chemical Engineers AIChE J, 61: 2647–2656, 2015

Biomass/coal steam co-gasification integrated with in-situ CO2 capture

Addressing recent environmental regulations on fossil fuel power systems and both biomass fuel supply and coal greenhouse gas issues, biomass/coal co-gasification could provide a feasible transition solution for power plants. In the quest for an even more sustainable process, steam co-gasification of switchgrass and coal was integrated with in-situ CO2 capture, with limestone as the bed material and sorbent. Five gasification/carbonation (at <700 °C) and calcination (at >850 °C) cycles were performed in an atmospheric pilot scale bubbling fluidized bed reactor. Hydrogen production was enhanced significantly (∼22%) due to partial adsorption of CO2 by the CaO sorbent, shifting the gasification reactions forward, consistent with Le Châtelier's principle. Tar yield measurements showed that reducing the gasification temperature could be achieved without experiencing higher tar yield, indicating that the lime has a catalytic effect. The sorbent particles decayed and lost their calcium utilization efficiency in the course of cycling due to sintering. The co-existence of three types of solids (biomass, coal, lime) with different particle properties led to bed segregation. An equilibrium model was found to be useful in design of lime-enhanced gasification systems.

Dy(III) recovery from dilute solutions using magnetic-chitosan nano-based particles grafted with amino acids

Magnetic-chitosan nano-based particles were successfully prepared by a simple one-pot co-precipitation method before being functionalized with three different amino acid groups (i.e., alanine, serine, and cysteine) using epichlorohydrin as the linking agent. The structural and functional characteristics of the nanosorbents were investigated by elemental analysis, Fourier transform infrared spectrometer, X-ray diffraction, TEM, and vibrating sample magnetometry. The sorption properties of these materials were tested for Dy(III) recovery from aqueous solution: pH effect, uptake kinetics, and sorption isotherms were investigated. Sorbent particles are super-paramagnetic and their size is in the range of 15–40 nm. Kinetic profiles are successfully modeled with the pseudo second-order rate equation. The Langmuir and the Dubinin–Radushkevich equations fit well-sorption isotherms. The maximum sorption capacities at pH 5 (optimum pH, and at T: 27 ± 1 °C) are close to 14.8, 8.9, and 17.6 mg Dy g−1 for alanine, serine, and cysteine type, respectively. Cationic species RE(III) in aqueous solution appear to be sorbed by combined chelation and anion-exchange mechanisms. The sorption process begins at low-metal concentration by a physical monolayer sorption at low ion concentration before metal ions can be sorbed at higher metal concentration by coordination. The values of the thermodynamic parameters ΔG° and ΔH° indicate the spontaneous and endothermic nature of the mechanism, while the positive values of ΔS° show that during the sorption process the randomness increases. Finally, the sorbent can be efficiently regenerated using acidified thiourea: the amount of Dy(III) sorbed is hardly reduced, at least during the first four sorption/desorption cycles.