Dilute H2SO4 Solution Research Articles

Recovery of rare earth elements from phosphogypsum waste in resin-in-leach process by eluting with biodegradable complexing agents

Phosphogypsum waste is a potential, secondary rare earth element (REE) source that is available in very large volumes. Extraction and purification of REE from this complex waste was studied using resin-in-leach (RIL) followed by batch elution. Multiple consecutive RIL cycles with Purolite S940 resin in dilute H2SO4 solution were performed for an industrial phosphogypsum waste. REE loading (max. 0.92 equiv./kg) and purity over calcium (70%) increased up to seven cycles. REE and the impurities were separated by treating the loaded resin in a packed bed column with a two-step elution procedure. Calcium was efficiently removed with 0.06 M HCl. Alkaline solutions of biodegradable chelating agents N,N–dicarboxymethyl glutamic acid (GLDA), methylglycinediacetic acid (MGDA), oxalic acid, citric acid and iminodiacetate were studied for the second elution step. MGDA and GLDA were both suitable candidates for effective REE elution from S940 resin. A calcium free, high purity REE fraction (up to 99.01%) was obtained with MGDA. The most likely REE:MGDA complex stoichiometry was found to be 1:1 by using the method of continuous variation.

Corrosion inhibition study and statistical data of thymus mastichina and alicium verum oil on low carbon steel in dilute H2SO4 and HCl solution

Data on the corrosion inhibition of thymus mastichina and alicium verum (TA) on mild steel in H2SO4 and HCl solution was evaluated by coupon measurement and statistically through analysis of variance. The inhibition performance of TA was observed to decrease significantly with exposure time at 1% TA, beyond which the extent of decrease reduced. In HCl solution TA inhibition efficiency varied significantly with exposure time from 1%-4% TA concentration. Data showed TA effectively inhibited the mild steel after 1% concentration with optimal value of 81.24% and 5% TA concentration. TA performed poorly in HCl with optimal value of 68.33% at 5% TA concentration. Standard deviation showed variation of TA inhibition efficiency from mean inhibition value was significant at 1-5% TA concentration in HCl and at 1% TA concentration in H2SO4. 88% of TA inhibition data were above 70% inhibition with respect to exposure time and TA concentration at margin of error of +0.09% compared to 53% in HCl at margin of error of +0.1%. Analysis of variance showed TA concentration is the dominant source of variation responsible for the inhibition performance of TA with statistical relevance value of 88.83% while TA concentration and exposure time were both influential in HCl solution with values of 67.96% and 26.97%.

The dissolution characteristics and wire electrochemical micromachining of metallic glass Ni82Cr7Si5Fe3B3

Abstract Wire electrochemical micromachining (WECMM) is a non-traditional technique that is suitable for micro-structures processing of metallic glass (MG). The composition of metallic glass is complex, and the electrochemical characteristics of metallic elements are different, which greatly increases the difficulty of high-quality electrochemical micromachining of MG. In this study, the electrochemical dissolution characteristics of the amorphous material, Ni82Cr7Si5Fe3B3, are analyzed in detail. The AC impedance spectrum and dissolution states of MG in 0.1 M NaCl, NaNO3, HCl, and H2SO4 solutions are explored, and the dissolution characteristics of metal elements in Ni82Cr7Si5Fe3B3 are also investigated to determine the electrolytic properties of MG. By comparing the results of WECMM experiments in different solutions, the appropriate solution was chosen as electrolyte, and the effects of different parameters on WECMM of Ni82Cr7Si5Fe3B3 were studied. Finally, the optimal processing parameters achieved by the experiments, 0.25 M dilute H2SO4 solution, ultrashort pulse voltage amplitude 7 V, pulse period 3 μs, a pulse duration of 90 ns and a feed rate of 0.2 μm/s were applied to complete the machining of the MG micro-slits. And several complex micro-structures with good surface morphology were thus obtained. For example, a gear with an index circle diameter of 1 mm, a curved cantilever beam with a width of 30.5 μm and a micro round wheel with the thickness of 100 μm.

Inhibition effect of sodium benzoate, zinc benzoate and zinc bromide on low carbon steel corrosion in dilute H2SO4 and HCL solution

The corrosion inhibition performance of inorganic chemical compounds of sodium benzoate, zinc benzoate and zinc bromide on low carbon steel was studied in 0.5 M H2SO4 and HCl solution at volumetric concentrations of 10%, 30%, 50% and 70%. Results obtained from LCS inhibition in H2SO4 showed sodium benzoate performed poorly with highest and lowest inhibition efficiency value of 50.5% and 36.24% at concentrations of 70% and 10%. Zinc bromide performed most effectively in H2SO4 with highest and lowest results of 90.96% and 76.96% at concentrations of 50% and 10%. Zinc benzoate displayed good results with peak value of 88.32% at 70% concentration and lowest value of 46.79% at 10% concentration. The corresponding performance of the compounds in HCl solution showed zinc benzoate performed more effectively with highest and lowest value of 70.17% and 33.26% at concentrations of 50% and 10%. Sodium benzoate and zinc bromide displayed average performance in HCl solution with optimal values of 67.38% and 55.40% at 30% concentration. Statistical analysis through analysis of variance showed exposure time is the only relevant factor (independent variable) in both acids responsible for the inhibition performance of the compounds with significance factor above 100%. The second independent variable (inhibitor concentration) was determined to be statistically irrelevant with significance factor below zero.

A bottom-up acidification strategy engineered ultrathin g-C3N4 nanosheets towards boosting photocatalytic hydrogen evolution

At present, graphene-like carbon nitride (g-C3N4) has been considered as a promising photocatalyst for photocatalytic hydrogen gas (H2) evolution from water. The top-down treating of pristine bulk g-C3N4 (CN–B) by strong acid is an efficient modification way to improve photocatalytic performance, yet this strategy is environmental unfriendly because it requires higher strong acid concentration. To this end, here we firstly developed an available bottom-up acidification strategy to prepare the 2D ultrathin g-C3N4 nanosheets (UCNs) by the direct calcination of as-formed precursor derived from hydrothermal treating of melamine merely in diluted H2SO4 solution. As a result, the engineered UCNs with an average thickness of approximately 3 nm exhibited a remarkably enhanced visible-light-driven photocatalytic H2 evolved rate of 2590 μmol g−1 h−1 (λ > 400 nm), which is over 9.9-folds and 2.2-folds larger than that of CN–B and acid-treated g-C3N4 (CN-A) under the same condition, respectively. Our research offers a feasible and effective bottom-up acidification strategy for synthesizing the high-performance UCNs photocatalyst towards renewable solar energy conversion.

Enhancement of Liquid and Gaseous Biofuels Production From Agro-Industrial Residues After Thermochemical and Enzymatic Pretreatment

In the present study the effect of thermo-chemical pretreatment and enzymatic hydrolysis on the saccharification and the further bioconversion of two different types of lignocellulosic agro-industrial residues to bio-ethanol and methane, was investigated. The residues used were the sunflower straw (SS) and the cracked olive stones (OS) remaining after olive oil production process. Biomasses were subjected to simultaneous chemical and thermal pre-treatment using either dilute H2SO4 or dilute NaOH aqueous solutions of concentrations 0.5%, 1% and 1.5% (w/v), at 121 oC for 60 min. The saccharification of the complex carbohydrates due to pretreatment was determined in terms of sugars released, and the effect of each pretreatment was evaluated statistically. The effect of the enzymatic hydrolysis of the biomasses using commercial cellulolytic enzymes on saccharification was also assessed and statistically evaluated in terms of different enzymatic loadings. Subsequently, the pre-treated wastes were used as substrate for methane and ethanol production using mixed methanogenic consortia and the yeast Pachysolen tannophilus, respectively.

Optimization of Acid and Steam Explosion Pretreatment of Cogon Grass for Improved Cellulose Enzymatic Saccharification

Acid-impregnation and its combination with steam explosion were evaluated and optimized using Response Surface Methodology. At 10% solid-liquid ratio, cogon was impregnated with diluted H2SO4 solution (0 to 3%, w/w) at different ranges of temperature (40 to 120 °C) and varied time (0 to 130 min). Impregnated samples were then subjected to enzymatic saccharification using 60 FPU/g Accelerase 1500™. After enzymatic saccharification, the concentration of reducing sugar released was measured using Dinitrosalicylic (DNS) Colorimetric Method. Based on the results, Response Surface Model (RSM) showed that the optimum condition, predicting 7.18% Reducing Sugar Yield (RSY), was impregnation of cogon using 1.9% H2SO4 at 91.8 °C for 56 min. Experimental verification of optimum condition, done in triplicates, showed 6.35 + 0.05% RSY. Acid-impregnated cogon was subjected to steam explosion to improve saccharifiability. Factors varied were temperature (137 to 222 °C) and exposure time (17 to 582 s). Steam-exploded samples were saccharified and RSY was determined. RSM indicated that the best steam explosion condition, predicting 7.91% RSY, was 179 °C and 500 s. Experimental verification of optimum condition showed 8.78 + 0.02% RSY. Using RSY as basis, steam explosion improved saccharifiability of H2SO4-impregnated cogon by 38%, thus, increasing production of reducing sugars for potential bioethanol production.

Hydrodynamic Analysis of Hydrolysis of the Rice Husk Cellulose by Using CFD Modeling

The importance of the rule and the demand of glucose trigger the seeking of the alternative materials to produce glucose. One of the alternatives used is the utilization of biomass such as the rice husk to produce glucose. Rice husk is the agricultural residue whose availability is very abundant. In this research, rice husk contained cellulose (42.2 %), hemicellulose (17.04 %), and lignin (20.46 %). First step to produce the glucose from rice husk was pretreatment stages (Soaking in Aqueous Ammonia pretreatment and Acid pretreatment). Furthermore it was followed by the acid hydrolysis step by using dilute H2SO4 solution. The concentration of H2SO4 used in this work was 1, 2, and 3 N with the various hydrolysis times of 30, 60, 90, 120, and 150 min. The result showed that increasing of hydrolysis time slightly increased glucose concentration. The highest glucose concentration was about 21.51% at H2SO4 concentration of 2 N and the hydrolysis time of 150 min. CFD modeling (ANSYS Fluent 16) was performed to investigate the hydrodynamic phenomena during hydrolysis. The hydrodynamic analysis showed that the best mixing occurred at H2SO4 concentration of 2 N for 150 min. It is a good agreement with the experimental finding.

Fermentative Production of Ethanol from Acid Hydrolyzate of Rice Water Waste Using Saccharomyces cerevisiae: Experimental and Kinetic Studies

Rice water waste, a starch-bearing effluent waste stream, was utilized as an abundant and low-cost substrate for ethanol production. Prior to the fermentation process, rice water waste was hydrolyzed using dilute H2SO4 solution. To attain the highest concentration of sugars with a minimum amount of inhibitory by-products during the acid hydrolysis, different acid concentrations (2–6 v/v %), hydrolysis temperatures (60–100 °C) and reaction times (0–200 min) were examined. The maximum catalytic efficiency (ηE = 27.36) was obtained using 4% H2SO4 at 80 °C for 100 min; wherein, the concentration of reducing sugars, furfural and 5- hydroxymethylfurfural (HMF) in the hydrolyzate was 43.32, 0.29 and 0.17 g L−1, respectively. This hydrolyzate was utilized as a substrate for ethanol fermentation using Saccharomyces cerevisiae; the maximum ethanol concentration, yield, and cell density were 18.65 g L−1, 0.41 g ethanol g−1 sugar and 3.68 g L−1, respectively. The kinetics of the acid hydrolysis process was studied using “two-fraction” model. The kinetic constants indicated that the rate of release of reducing sugars from starch was high; while, the degradation rate of reducing sugar to furfural and HMF was negligible. Moreover, multi-response nonlinear regression analysis was performed on the experimental data to determine the kinetic parameters regarding cell growth, substrate utilization, and ethanol production.

Hidrolisis Ampas Biji Sorgum dengan Microwave untuk Produksi Gula Pereduksi sebagai Bahan Baku Bioetanol

Sorgum merupakan tanaman serealia yang dapat tumbuh pada berbagai keadaan lingkungan sehingga potensial dikembangkan, khususnya pada lahan marginal beriklim kering di Indonesia. Sorgum manis mempunyai potensi yang besar digunakan sebagai bahan baku etanol selain tebu. Budidaya sorgum manis mengalami pergeseran dari bahan baku pangan dan pakan menjadi bahan baku industri, baik skala kecil maupun skala besar. Penelitian ini bertujuan untuk mendapatkan kadar gula pereduksi sebagai bahan baku bioethanol melalui hidrolisis menggunakan microwave. Sebanyak 10 gram serbuk sorgum disuspensi dengan larutan H2SO4 encer 0,1 N, 0,3 N dan 0,5 N sebanyak 250 mL lalu dipanaskan menggunakan iradiasi microwave pada temperatur 200 oC selama 20 dan 40 menit. Fraksi cair hasil hidrolisis dianalisis kandungan gula pereduksi dengan metode DNS menggunakan spektrofotometer UV-Vis. Hasil yang diperoleh menunjukkan bahwa kondisi optimum hidrolisis menggunakan microwave dicapai pada konsentrasi H2SO4 0,5 N temperatur 200 oC dan waktu hidrolisis 40 menit. Kadar gula pereduksi sebesar 42,71 mg/L. Kadar gula naik sebesar 19,95% dibanding waktu hidrolisis 20 menit.

Enhanced selective recovery of selenium from anode slime using MnO2 in dilute H2SO4 solution as oxidant

As important rare raw material, Se and its compounds are widely used in metallurgy, glass manufacturing, chemicals and pigments, and electronics industry. However, current processes used for Se recovery are usually constrained by the serious pollution and high energy consumption. To dispose the issues in the process of Se recovery, this study developed an environmentally friendly process by using MnO2 in dilute H2SO4 as oxidant to efficiently recover Se and Cu. The effects of MnO2 dosage, H2SO4 concentrations, stirring speeds and temperature on the recovery were investigated. It was found that the major Se bearing phases in anode slime were elemental Se and Ag2Se. The oxidation capacity of MnO2 greatly increased with the H2SO4 concentration higher than 0.5 M and at a temperature above 60 °C. Optimum conditions derived from this study were 1.2 g MnO2 dosage, 1.0 M H2SO4, 600 rpm, and temperature at 80 °C, under which both the Se and Cu were recovered by 100% after 6 h. The cost-benefit analysis of the proposed process manifested that the profit of processing 1 t of anode slime was $ 82, and the sensitivity analysis showed that the price of Cu2Se and the Se recovery rate were the most important determinants of the profit. This research has great potential in Se recovery from anode slime.

Corrosion failure analysis of a railway tanker containing concentrated sulfuric acid

In this paper, the authors carried out a corrosion failure analysis of a railway tanker containing 92.5% sulfuric acid, in order to investigate the cause of the leakage accident that occurred in 2016 and to provide a theoretical basis for preventing similar accidents. The morphology and chemical composition of the corrosion scale were characterized by SEM and EDS. The theoretical corrosion rate of the railway tanker was calculated using weight loss experiments. The corrosion behavior model was established by electrochemical experiments. In order to investigate the cause of this leakage, a mechanical model was established, and the force of the railway tanker during transportation was analyzed through ANSYS software. The results show that the tanker material (low-alloy high-tensile structural steel, Q295A) meets the quality standard, and the main cause of this leakage accident was the local corrosion failure of the tanker leading to a crack due to stress during the transportation process. The corrosion source is diluted H2SO4 solution. The main component of the corrosion scale was Fe2O3. The theoretical corrosion rate was in the range of 1.413–1.978 mm/a, and the corrosion rate increased with the decrease in the concentration of H2SO4. The corrosion type was pitting corrosion. When the brake is applied when the tanker is in full load, the stress inside the tanker is about 8.94 times higher compared to a tanker with empty load in the static state. Because of this uneven force, a crack may develop leading to leakage from the corroded area of the tanker.

Highly catalytical performance of nanoporous copper for electro-oxidation of methanol in alkaline media

Three-dimensional interconnected nanoporous coppers (NPCs) were synthesized by the dealloying of Cu-Ti and Cu-Ti-Ni amorphous ribbons in dilute H2SO4 solution. The effects of glassy precursor composition on the morphologies of NPC were evaluated comprehensively. The specific surface area of the NPC samples prepared by dealloying Cu66Ti30Ni4 (28.735 m2 g-1) and Cu68Ti30Ni2 (20.196 m2 g-1>) amorphous alloys is much larger than that of the Cu70Ti30 (9.080 m2 g-1), indicating that the addition of minor amount of nickel has a great influence on the microstructure of NPC. Then, NPC with different microstructures were applied in the electro-oxidation of methanol in alkaline media. Among three catalysts, the NPC dealloyed by Cu66Ti30Ni4 amorphous ribbon exhibited the highest electrocatalytic activity (anodic peak current density: 298 mA cm−2, presence of 1 M CH3OH in 1 M KOH solution) toward methanol oxidation, which is attributed to the larger number of active sites on the surface.

Up-grading of natural ilmenite ore by combining oxidation and acid leaching

Rutile (TiO2) is heavily used in pigments and colorants, and the most abundant source of rutile is ilmenite. Upon oxidation of ilmenite, rutile can be formed with modest energy consumption; furthermore, after leaching, only a few byproducts are formed. Unfortunately, one drawback is the necessarily long oxidative process of typically used methods. In this study, we show that a fluidized bed reactor can be used to oxidize ilmenite ore to rapidly form rutile and pseudobrookite (Fe2TiO5) phases. Ilmenite was oxidized with 5vol% O2 in Ar at temperatures of 1173 K or 1223 K and subsequently leached using a diluted H2SO4 solution to dissolve the pseudobrookite phase. The effects of acid concentration, temperature, and cooling rate after oxidation were investigated. We show that the ilmenite was rapidly oxidized to form rutile and pseudobrookite phases at 1173 and 1223 K in a 5vol% O2/95vol% Ar environment within 40 min. The final maximum rutile yield was 84.2mol% after leaching in (1 + 1) H2SO4 solution at 393 K for 12 h.

Analysis of SiC grain size variation and NaCl concentration on the corrosion susceptibility of AA1070 aluminium matrix composites

Analysis of the impact SiC grain size at 10% wt. on the corrosion resistance of AA1070 aluminium matrix composites was studied in Cl− anion containing dilute H2SO4 solution. Studies were performed ...

Selection of a synergistic solvent extraction system to remove calcium and magnesium from concentrated nickel sulfate solutions

Synergistic solvent extraction of Ca and Mg from concentrated Ni sulfuric solutions was assessed using extractants Cyanex 272, D2EHPA, and naphthenic acid. D2EHPA has a strong preference for extracting Ca; however, Ca was crowded out by Ni at pH>3.5. Cyanex 272 has a higher affinity for Mg at pH>5, while both earth alkaline metals are rejected by naphthenic acid at pH=2–6 as well as by the system Cyanex 272+naphthenic acid. The system D2EHPA+naphthenic acid has affinity only for Ca. The system D2EHPA+Cyanex 272 can extract Ca and Mg simultaneously; however, selectivities Ca/Ni and Mg/Ni are dependent on the liquor pH and D2EHPA concentration in organic mixture solution. In this system, a strong synergistic effect was found for Ca and Mg, whereas contradictory behavior was observed for Ni. To avoid crud formation, the selective extraction of Ca and Mg should be performed at pH<6. Ni can be selectively stripped from the loaded D2EHPA+Cyanex 272 using diluted H2SO4 solution, whereas Ca and Mg can be completely stripped with concentrated H2SO4 solution.

Solvent extraction of calcium and magnesium from concentrate nickel sulfate solutions using D2HEPA and Cyanex 272 extractants

Selective solvent extraction of Ca and Mg was applied to purify Ni from a concentrate sulfate solution ([Ni]=88g/L, [Mg]=3.1g/L, [Ca]=0.5g/L). In the first extraction circuit using D2EHPA as an extractant, 98.6% Ca were extracted (2 stages, [D2EHPA]=0.3M, pH3, 50°C, A/O ratio=1). The co-extracted Ni (~2.8%) was selectively stripped out (99%) from the loaded organic phase with only 2.6% Ca using a dilute H2SO4 solution (2 stages, [H2SO4]=0.038M, 50°C, A/O ratio=1). Over 99% Ca were stripped out from the loaded D2EHPA in one theoretical stage with 2M HCl (O/A ratio=15). The aqueous solution depleted in Ca was subjected to the second extraction circuit using Cyanex 272 as an extractant, where 99% Mg were extracted (3 stages, [Cyanex 272]=0.32M, pH5.7, 50°C, A/O ratio=1). The co-extracted Ni (~6.9%) was recovered (99%) from the loaded organic phase with only 2.1% Mg using a dilute H2SO4 solution (3 stages, [H2SO4]=0.031M, 50°C, A/O ratio=1). Magnesium was stripped out (>99%, 50°C) from the loaded Cyanex 272 in one theoretical stage using 2M H2SO4 or 3M HCl (O/A ratio=20 or 11, respectively). The purified liquor with approximately 80g/L Ni is suitable for electrowinning. The apparent equilibrium constants using real concentrations of metals were obtained.

Removal of iron from sythetic copper leach solution using a hydroxy-oxime chelating resin

Iron removal is a common procedure in hydrometallurgy of non-ferrous metallic ores. Chemical precipitation and solvent extraction are currently the main methods employed for separation of iron from copper leach solution. However, chemical precipitation methods have the problem of producing large amounts of iron precipitates, and/or requiring high temperature and high pressure conditions for precipitation. The precipitates are difficult to separate from the solution. Emulsification is a general problem for solvent extraction, which causes loss of extractants and contamination of the electrolyte. A common problem for solvent extraction and chelating ion exchange processes is the difficult iron stripping process. Therefore, finding an efficient and environmentally friendly method for iron removal is of great significance. In this paper, new processes of using ion exchange resins to remove iron from copper leach solution have been investigated.Salicylic acid, amino carboxylic acid, amino phosphonic acid and hydroxy-oxime resins were employed to adsorb iron from a synthetic copper leach solution containing 40g/L of Cu2+ and 36g/L of Fe3+. It was found that a hydroxy-oxime resin, named Z-Fe, has excellent adsorption selectivity on Fe3+. Desorption behavior of the resin was studied by two step elutions using dilute H2SO4 and oxalic acid solution, respectively. After optimizing the adsorption-elution processes, the extent of removal of iron from the simulated copper leach solution using resin Z-Fe was 89.83%, while copper recovery could reach 100% in closed circuit processing.

Regeneration of commercial selective catalyst reduction catalysts deactivated by Pb and other inorganic elements

The regeneration of commercial SCR (Selective Catalyst Reduction) catalysts deactivated by Pb and other elements was studied. The deactivated catalyst samples were prepared by chemical impregnation with mixed solution containing K2SO4, Na2SO4, CaSO4, Pb(NO3)2 and NH4H2PO4. A novel method combining Ethylenediaminetetraacetic acid disodium salt (EDTA-2Na) and H2SO4 solution (viz. catalysts treated by dilute EDTA-2Na and H2SO4 solution in sequence) was used to recover the activity of deactivated samples, and the effect was compared with single H2SO4, oxalic acid, acetic acid, EDTA or HNO3 solutions. The surface structure, acidity and reducibility of samples were characterized by N2 adsorption–desorption, inductively coupled plasma optical emission spectrometer (ICP-OES), scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray fluorescence (XRF), H2-temperature programmed section (H2-TPR), NH3-temperature programmed desorption (NH3-TPD) and in situ DRIFTS. Impurities caused a decrease of specific surface area and surface reducibility, as well as Brønsted acid sites, and therefore led to severe deactivation of the SCR catalyst. The use of an acid solution alone possibly eliminated the impurities on the deactivated catalyst to some extent, and also increased the specific surface area and Brønsted acid sites and promoted the surface reducibility, thus recovered the activity partially. The combination of EDTA-2Na and H2SO4 could remove most of the impurities and improve the activity significantly. The removal of Pb should be an important factor for regeneration. Due to a high removal rate for Pb and other impurities, the combination of EDTA-2Na and H2SO4 solutions provided the best efficiency.

Removal of Strontium Ions by Synthetic Nano Sodalite Zeolite from Aqueous Solution

In this research, the zeolite sodalite, as an inorganic ion exchange material, was chemically produced in the template-free synthesis and evaluated in order to facilitate the sorption of strontium ions from aqueous solutions in batch operations onto acid treated zeolite with dilute H2SO4 solutions. The following indicates what the batch experiments included: a sorbent amount of 0.25 g in 100 mL of strontium solution (50 mg/L), a contact time of 80 min, pH 6 and a 20 oC temperature. To study the kinetics of removal process, three equations, i.e. Morris–Weber, Lagergren (pseudo first order) and pseudo second order were used. The sorption data were applied to the Langmuir, Freundlich, Dubnin-Randkovich (D-R) and Temkin models in order to estimate the sorption capacity, intensity and energy. An evaluation of the thermodynamic parameters ΔH, ΔS and ΔG was done. It was found out from thermodynamic parameters that the sorption of strontium onto zeolite was feasible, spontaneous and endothermic under studied conditions.