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EN
In this work, the affinity of the heterogeneous Sorbonorit B4 (SB4) activated carbon toward methyl ethyl ketone (MEK), isopropyl alcohol (IPA), n-propyl alcohol (NPA) and isobutyl alcohol (IBA), and water vapours was examined. Adsorption equilibrium measurements demonstrate a higher adsorption capacity of water vapour than organic compounds at relative pressures above 0.4. The adsorption capacities of SB4 at the same vapor pressure followed the order: NPA> IPA> MEK> IBA. The Langmuir, Dubinin-Radushkevich, Dubinin-Astakhov, and Toth isotherm models were chosen to describe experimental results. Based on the multi-temperature isotherms, the values of the isosteric heat of adsorption were determined for various adsorbate loading. The results indicate a strong influence of VOC molecule structures and the surface heterogeneity of SB4 on the adsorption efficiency. For IPA-SB4 pair, the maximum temperature rise in a fixed-bed bed in the adsorption process and the energy requirement for regeneration were calculated and experimentally verified.
EN
Contamination of water bodies by heavy metals is a continuously growing environmental issue. High concentrations of mercury (Hg) in river waters are a recognized environmental problem, because it is one of the most toxic heavy metal ions as it causes damage to the central nervous system. Its negative impact has led to the development of different methods for the treatment of effluents contaminated with Hg(II). The aim of this article is to evaluate the use of coffee (Coffea arabica) residues as adsorbent of Mercury in an aqueous solution. Four kinetic models, including intraparticle diffusion, pseudo-first-order, pseudo-second-order, and Elovich kinetic models were applied to explore the internal mechanism of mercury adsorption. Results indicate that the pseudo-first-order and pseudo-second-order models could accurately describe the adsorption process. It means that chemical adsorption play an important role in the adsorption of mercury by activated carbon. Meanwhile, the external mass transfer process is more effective in controlling the activated carbon mercury adsorption according to the fitting result of the pseudo-first-order model. The fitting to Langmuir’s model suggested that the material surface is energetically homogeneous. The technique of contaminated biomass encapsulation proved to be safe for short-term disposal when metal recovery is not desired.
EN
Ultrasonically improved electrochemically generated adsorbent (UEGA) has been synthesized and used for adsorption of fluoride ions from fluoride laden waste water. UEGA was prepared in two major steps, firstly electrochemically generated adsorbent (EGA) was prepared using electrolytic method followed by ultrasonication treatment. Ultrasonication causes size reduction which leads to increase in surface area viz. active site which helps to enhance attachment of negatively charged fluoride ion on positively changed UEGA from waste water. UEGA was prepared at three different amplitude i.e. 50, 70 and 90% respectively. Taguchi optimization for defluoridation was carried out considering operating parameters such as initial concentration; contact time; adsorbent dose; and temperature. The results obtained demonstrated that adsorption showed different fluoride removal at varying frequency. This study proved that varying percentage amplitude of ultrasonication significantly affects defluoridation efficiency.
EN
The use of guava seeds (GS) and acid-modified guava seeds (MGS) for the removal of Cr(VI) from aqueous solutions was investigated. Batch-type experiments were performed with Cr(VI) aqueous solutions and biosorbents to determine the kinetic and equilibrium sorption parameters. Results indicated that GS and MGS were capable of reducing and remove Cr(VI) from solutions, but the reduction was only observed at some experimental conditions. Infrared analysis showed that several functional groups were involved in the reduction, and biosorption of Cr(VI), particularly alcohol, phenolic, carboxylic, and methoxymethyl structures. The mechanisms of reduction and biosorption depended upon the type of biosorbent, pH, and temperature of the system. The pseudo-second-order kinetic model describes the kinetic sorption data, and the Langmuir-Freundlich (L-F) model describes the isotherm data in most cases. Significantly high total chromium biosorption capacities were obtained. Acid modification of guava seeds improves chromium biosorption performance.
EN
In this paper, an unsteady 2-D incompressible fluid flow with heat and mass transfer in a four-sided lid driven square cavity is investigated numerically. The top, bottom, left, and right walls of the square cavity move to the right, left, downward and upward respectively. All four sides of the cavity move with a uniform velocity. The flow variables are simulated below the critical Reynolds numbers with isothermal and mass-transfer conditions in the square cavity. We have used a streamfunction-vorticity (ψ - ξ) formulation to investigate the fluid flow in terms of flow variables ψ, ξ, T and C at low Reynolds numbers (Re). The Prandtl number (Pr) and Schmidt number (Sc) have been chosen as 6:62 and 10, 50, 100, 150 respectively, in order to calculate the numerical solutions of T and C. The matrix method has been used to evaluate the stability and convergence of the numerical scheme. The conditions obtained from the matrix method have been used to arrive at the numerical solutions with desired accuracy.
EN
This paper presents an experimental study on Cochineal Red A dye adsorptive removal by yeast. Batchequilibrium and kinetic tests were conducted in constant temperature of 30◦C for the dye’s initialconcentration range of 0.02–0.50 g/L (pH=3and 10) and 0.02–0.35 g/L (pH=7:6). The equilibriumwas reached after 105–120 min. Yeast demonstrated the adsorption capacity of 10.16 mg/g for acidicenvironment (pH=3) and slightly lower values (8.13 mg/g and 8.38 mg/g respectively) for neutral(pH=7:6) and alkaline environment (pH=10). The experimental equilibrium results were fitted withLangmuir, Freundlich, Sips and Toth isotherm models. Most of them (Freundlich model being theexception) were proven sufficient for the experimental data correlation. The adsorption kinetic studiesshowed that the pseudo-second order model fits better the experimental data than the pseudo-first-order model. Results achieved from intra-particle diffusion model indicate that powdered yeast are anonporous adsorbent. The percentage of solution discoloration reached a maximum value of 75% atpH=3for an initial dye concentration of 0.02 g/L.
PL
Adsorpcja to jeden z ważniejszych procesów zachodzących na powierzchniach adsorbentów. Dokładne zbadanie właściwości sorpcyjnych pozwala także na sprecyzowanie dalszego zastosowania danego materiału. W badaniach ‒ w celu określenia właściwości badanych próbek dwutlenku tytanu oraz dwutlenku tytanu z dwutlenkiem manganu ‒ wyznaczano izotermy adsorpcji błękitu metylenowego na badanych materiałach: TiO2 oraz TiO2 + MnO2. Substancje te znajdują zastosowanie w procesie oczyszczania środowiska naturalnego z zanieczyszczeń spowodowanych produktami ropopochodnymi, które stanowią poważne zagrożenie dla całego ekosystemu. Badania laboratoryjne pozwalają na dokładniejsze poznanie właściwości sorbentów i określanie coraz nowocześniejszych i bardziej skutecznych sposobów utylizacji wycieków ropy naftowej i jej pochodnych zarówno podczas przerobu, transportu, jak i eksploatacji.
EN
Adsorption is one of the most important processes occurring on the surfaces of adsorbents. A thorough examination of sorption properties also allows the specification of further use of a given material. In order to determine the properties of the tested titanium dioxide and titanium dioxide with manganese dioxide samples, isotherms of methylene blue adsorption on the tested materials: TiO2 and TiO2 + MnO2 were determined. These substances are used in the process of cleaning the environment of pollution caused by petroleum products, which pose a serious threat to the entire ecosystem. Laboratory tests allow for a more accurate understanding of the properties of sorbent and determination of increasingly modern and more effective ways of utilizing oil spills and its derivatives during processing, transport and operation.
EN
Fly ash and slag were examined for the removal processes of Pb(II) ions from water in batch experiments under different conditions of adsorbent dosage, initial concentration, pH and contact time. The materials are industrial waste generated from the high temperature treatment of sewage sludge by the circulating fluidized bed combustion (CFBC) technology. Physical and chemical properties, as well as adsorption efficiency and calculated maximum adsorption capacity of Pb(II) ions were determined using a variety of methods. The kinetic analysis revealed that the adsorption process is better described by the pseudo-second order equation and it is well fitted to the Freundlich model.
EN
Sulphuric acid leach solution of waste printed circuit boards (PCBs) contains predominantly copper and iron with later remain problematic during electrowinning of the formal. In this study, performance of Dowex M 4195 resin for recovery of copper and nickel from polymetallic sulphate leach solution of waste PCBs was investigated by batch experiments. It was observed that at pH 0.5, about 45.2 and 3.6 % Cu2+ and Ni2+ was selectively recovered respectively. Recovery efficiency of Ni2+ increased with increase in pH from 0.5 -5.0 while pH2 was optimum for the recovery of Cu2+. Sharp increase in co-recovery of Fe3+/Fe2+ was observed at pH above 2 with that of Zn2+ and Co2+ became low due to hindrance from binding site by high concentration of Cu2+. Adsorption data obtained for Cu2+ and Ni2+ were tested with adsorption isotherms as well as kinetics. It is shown that adsorption of Cu2+ and Ni2+was well fitted to both Langmuir and Freundlich isotherm. Kinetics of Cu2+ and Ni2+ fitted into Pseudo-first and well fitted to second order. Reuse studies shows that the resin strong affinities for Cu2+ and Ni2+ remain unchanged.
EN
The aim of the study is to find out, based on the project’s approach, the main components of the project on the research of the microclimate of industrial premises, and to substantiate, develop and apply a means of geometric analysis of the graphic dependencies of its parameters. A comparative analysis of the graphic dependencies indicates the significant effect of local exhaust ventilation on the character of the temperature field in the room. The comparative analysis of results makes it possible to analyze the insulation of isotherms, that is, the effect of local exhaust ventilation on the nature of their location in a cutting plane. The practical significance of the scientific results obtained in the work is to develop a new methodical approach based on the combination of physical and geometric modeling using a constructive device of applied multidimensional geometry, which can be an instrumental basis for the purposeful study of similar technological processes in the production premises.
PL
Celem badania jest opracowanie głównych elementów projektu dotyczących badania parametrów mikroklimatu pomieszczeń przemysłowych oraz opracowanie i zastosowanie metody analizy geometrycznej zależności graficznych do oceny tych parametrów. Analiza porównawcza zależności graficznych wskazuje na znaczący wpływ lokalnej wentylacji wyciągowej na charakter pola temperaturowego w pomieszczeniu. Analiza wyników umożliwia ocenę uzyskanych izoterm charakteryzujących wpływ lokalnejwentylacji wyciągowej na ich położenie w płaszczyźnie cięcia. Praktyczne znaczenie wyników uzyskanych w pracy polega na opracowaniu nowego podejścia metodycznego opartego na połączeniu modelowania fizycznego i geometrycznego, co może stanowić podstawę do badania podobnych procesów technologicznych w pomieszczeniach produkcyjnych.
EN
To investigate the adsorptive properties of a local laterite deposited in Chenzhou, Hunan province, China, the adsorptive properties of the natural laterite were investigated by batch technique in this study. The effects of contact time, pH, ionic strength, temperature, and the concentration on adsorption properties were also analyzed. The obtained experimental results show that the main mineral composition of laterite is kaolinite and montmorillonite. The adsorption process achieved equilibrium within 60 minutes and 90 minutes for Sr(II) and Cr(VI), respectively. The adsorption capacities for Cr(VI) and Sr(II) by the laterite were about 7.25 mg·g-1 and 8.35 mg·g-1 under the given experimental conditions, respectively. The equilibrium adsorption data were fitted to the second-order kinetic equation. The adsorption capacity for Sr(II) onto the laterite increased with increasing pH from 3–11 but decreased with increasing ionic strength from 0.001 to 1.0 M NaCl. The Sr(II) adsorption reaction on laterite was endothermic and the process of adsorption was favored at high temperature. Similarly, the adsorption capacity for Cr(VI) onto the laterite increased with increasing pH from 3–11, however, the ionic strength and temperature had an insignificant effect on Cr(VI) adsorption. The adsorption of Cr(VI) and Sr(II) was dominated by ion exchange and surface complexation in this work. Furthermore, the Langmuir and Freundlich adsorption isotherm model was used for the description of the adsorption process. The results suggest that the studied laterite samples can be effectively used for the treatment of contaminated wastewaters.
EN
This paper proposes a method to numerically study viscous incompressible two-dimensional steady flow in a driven square cavity with heat and concentration sources placed on its side wall. The method proposed here is based on streamfunction-vorticity (Ψ-ξ) formulation. We have modified this formulation in such a way that it suits to solve the continuity, x and y-momentum, energy and mass transfer equations which are the governing equations of the problem under investigation in this study. No-slip and slip wall boundary conditions for velocity, temperature and concentration are defined on walls of a driven square cavity. In order to numerically compute the streamfunction Ψ, vorticityfunction ξ , temperature θ, concentration C and pressure P at different low, moderate and high Reynolds numbers, a general algorithm was proposed. The sequence of steps involved in this general algorithm are executed in a computer code, developed and run in a C compiler. We propose that, with the help of this code, one can easily compute the numerical solutions of the flow variables such as velocity, pressure, temperature, concentration, streamfunction, vorticityfunction and thereby depict and analyze streamlines, vortex lines, isotherms and isobars, in the driven square cavity for low, moderate and high Reynolds numbers. We have chosen suitable Prandtl and Schmidt numbers that enables us to define the average Nusselt and Sherwood numbers to study the heat ad mass transfer rates from the left wall of the cavity. The stability criterion of the numerical method used for solving the Poisson, vorticity transportation, energy and mass transfer has been given. Based on this criterion, we ought to choose appropriate time and space steps in numerical computations and thereby, we may obtain the desired accurate numerical solutions. The nature of the steady state solutions of the flow variables along the horizontal and vertical lines through the geometric center of the square cavity has been discussed and analyzed. To check the validity of the computer code used and corresponding numerical solutions of the flow variables obtained from this study, we have to compare these with established steady state solutions existing in the literature and they have to be found in good agreement.
EN
Raw apricot kernel shells (AKS) and ultrasound-modified apricot kernel shells were used as adsorbents for the removal of Cr(VI) from aqueous solutions. For raw and modified AKS, the experimental data well fitted to the Langmuir isotherm and adsorption kinetics was suited to pseudo-second order kinetic model indicating chemisorption as the rate-limiting step. For raw and modified AKS, maximum adsorption capacities obtained from the Langmuir adsorption model were 6.5 mg/g and 9.9 mg/g, respectively. Maximum Cr(VI) adsorption was obtained at a pH 2 and optimum stirring speed was determined as 250 rpm. After ultrasound modification, an increase for Cr(VI) adsorption was observed. Raw AKS as low-cost natural biomaterial can be preferred for the removal of Cr(VI) when compared to other adsorbents. Ultrasonic modification can be used to improve the efficiency of Cr(VI) removal.
EN
Adsorption of La3+ and Dy3+ from their aqueous nitrate solutions on biohydroxyapatite (BHAP) originally prepared from raw pork bones by steam gasification of has been investigated for the La3+and Dy3+ concentrations within the range of 1.44·10–4–8.06·10–3 mol/dm3 and 2.71·10–5 5.68·10–3 mol/dm3, respectively. It was found that saturation of the lanthanide uptake occurred at 0.0625 moles of Ln3+ per mole of BHAP. Two model isotherms, i.e., Langmuir (qe = qmCe/((1/KL) + Ce)) and Freundlich (logqe = logKF + (1/n)logCe), were used to fit the adsorption data. The following isotherm parameters were found for La3+: qm = 0.1265 mol/kg, KL = 2701 dm3/mol, n = 5.61, KF = 0.283 (mol/kg)·(dm3/mol)1/n and for Dy3+: qm = 0.1223 mol/kg, KL = 3635 dm3/mol, n = 5.82, KF = 0.306(mol/kg)·(dm3/mol)1/n. A better correlation was found for the Freundlich model. A relatively high value of the n parameter in the Freundlich equation suggests heterogeneous chemisorption of lanthanide ions.
PL
Celem badań było określenie wpływu modyfikacji chemicznej odpadowego lotnego popiołu węglowego (FA) za pomocą roztworów HNO3, CH3COONH4 (AcNH4), NaOH oraz dietyloditiokarbaminianu sodu (NaDDTC) na adsorpcję jonów ołowiu(II) w obecności jonów kadmu(II) w układzie jedno- i dwuskładnikowym. Analizowano modele izoterm adsorpcji w układzie jednoskładnikowym, m.in.: Freundlicha, Langmuira, Redlicha-Petersona, Jovanoviča, Fumkina- Fowlera-Guggenheima, Fowlera-Guggenheima-Jovanoviča-Freundlicha oraz Halseya, a także w układzie dwuskładnikowym za pomocą rozszerzonego modelu Langmuira, Langmuira- Freundlicha oraz Jaina-Snoeyinka. W testach laboratoryjnych badano równowagę oraz kinetykę adsorpcji. Adsorpcję jonów Pb(II) i Cd(II) w układzie jednoskładnikowym za pomocą FA, FA-NaOH i FA-AcNH4 dobrze opisuje model Langmuira oraz Redlicha-Petersona. Najwyższą wartość maksymalnej pojemności adsorpcyjnej uzyskano w przypadku FA-NaOH, która wynosiła 220 mg·g–1 s.m. oraz 55 mg·g–1 s.m. odpowiednio dla jonów Pb(II) i Cd(II). Badania wykazały, że FA-NaOH posiadają większą selektywność względem jonów Pb(II) niż względem jonów Cd(II), co jest związane z wielkością promienia uwodnionego jonu metalu i wartością pierwszej stałej równowagi reakcji hydrolizy. Otrzymane dane kinetyczne adsorpcji zostały dobrze wyrażone za pomocą modelu pseudo-drugiego rzędu (R2 = 0,998), natomiast wykazały bardzo słabe dopasowanie do modelu pseudo-pierwszego rzędu (R2 < 0,8). Przeanalizowano model Elovicha oraz model sorpcji wewnątrzziarnowej, który wykazał, że proces sorpcji jonów Pb(II) i Cd(II) jest kontrolowany przez dyfuzyjną warstwę graniczną oraz dyfuzję wewnątrz porów.
EN
The increasing demand for energy throughout the world has led to an increase in the utilization of coal and, subsequently, in the production of large quantities of fly ash as a waste product. In the light of the increasing quantity of fly ash, with a growing demand for electrical energy and hence for thermal power plants, the main challenges faced by the researchers and planners have been to solve the various environmental problems that arise due to the unused and surplus quantity of fly ash. Fly ash is composed of minerals such as quartz, mullite, subordinately hematite and magnetite, carbon, and a prevalent phase of amorphous aluminosilicate. These oxides are very effective adsorbents. Hence, fly ash can be a promising candidate material for heavy metals removal. The aim of this study was to investigate the chemical modifications of coal fly ash (FA) treated with HNO3, CH3COONH4 (AcNH4), and sodium diethyldithiocarbamate (NaDDTC) as an adsorbent for the removal of lead(II) and cadmium(II) ions in single- and bi-component system. In laboratory tests, the equilibrium and kinetic adsorption were examined. The adsorption isotherm models in single-component system were analysed, among others Freundlich, Langmuir, Redlich-Peterson, Jovanovič, Fumkin-Fowler-Guggenheim, Fowler-Guggenheim-Jovanovič-Freundlich, and Halsey, as well as in bi-component system by means of extended Langmuir, Langmuir-Freundlich, and Jain-Snoeyink models. The maximum Pb(II) and Cd(II) ions adsorption capacity obtained from the Langmuir model can be grouped in the following order: FA-NaOH > FA-AcNH4 > FA > FA-NaDDTC > FA-HNO3. Adsorption of Pb(II) and Cd(II) ions in single-component system, both the Langmuir and Redlich-Peterson models for the FA, FA-NaOH, and FA-AcNH4 could be fitted to experimental data. The maximum monolayer adsorption capacity of the FA-NaOH was found to be 220 mg·g–1 dry mass and 55 mg·g–1 dry mass for Pb(II) and Cd(II) ions respectively. Equilibrium experiments shows that the selectivity of FA-NaOH towards Pb(II) ions is greater than that of Cd(II) ions, which is related to their hydrated ionic radius and first hydrolysis equilibrium constant. The adsorption kinetics data were well fitted by a pseudo-second-order rate model (R2 = 0.998) but showed a very poor fit for the pseudo-first order model (R2 < 0.8). The Elovich and intra-particle model were analysed, also revealed that there are two separate stages in the sorption process, namely, the external diffusion and the inter-particle diffusion. It was found that the chemical enhancement of coal fly ash by NaOH treatment yields an effective and economically feasible material for the treatment of Pb(II) and Cd(II) ions-containing effluents.
EN
Industrial effluents that carry dyestuff into natural water systems are serious environmental concern. Complex aromatic structures of dyes make them more stable and more difficult to remove from the effluents discharged into water bodies. In the present study, removal of reactive blue 29 dye with chitosan and modified chitosan with Cu complexes from aqueous solution was investigated in a batch adsorption system with respect to the changes in the contact time, pH of solution and chitosan dosage. Adsorption isotherms of the dye onto chitosan were also studied. The results revealed that the adsorption capacity of chitosan with Cu complexes is lower than that of chitosan without Cu complexes. Also effect of H2O2 on adsorption when we used chitosan without Cu complexes is more considerable. The results also demonstrated that adsorption capacity of reactive blue 29 dye on chitosan was higher at lower pHs. Finally, the Langmuir isotherm showed the best conformity to the equilibrium data.
17
Content available remote Adsorpcja lotnych związków organicznych na węglu aktywnym
PL
Wzrost produkcji przemysłowej powoduje problemy zarówno z odpadami, jak i wzrastającym zanieczyszczeniem atmosfery. Technologia adsorpcyjna wykorzystywana jest do kontrolowania emisji i odzyskiwania lotnych związków organicznych (LZO). Badano właściwości dwóch handlowych węgli aktywnych oraz węgla wytwarzanego w skali laboratoryjnej, pochodzących z różnych prekursorów. Oceniono strukturę porowatą węgli na podstawie izoterm adsorpcji i desorpcji argonu. Porównywano właściwości adsorpcyjne węgli aktywnych dla takich adsorbatów, jak alkohol metylowy, aceton oraz toluen.
EN
MeOH, PhMe and Me₂CO at 298 K. The pore texture of activated carbons was evaluated based on argon adsorptiondesorption isotherms.
EN
Sorption capacities of low-moor peats and Neogene clays from the overburden of lignite beds in Central Poland for Cr(III) ions as chloride and metalorganic complex ions have been investigated. The binding mechanisms and sorption parameters were determined based on the Freundlich and Langmuir nonlinear sorption isotherms. The sorption capacities of studied materials for Cr(III) ions depended on their properties (porosity, average pore diameters, specific surface area and content of Fe hydroxyoxides) as well as charge of Cr(III) ions, functional groups and their diagonal lengths. Cr(III) ions from chlorides were bound onto sorbents via Coulomb attraction and by Fe hydroxy-oxides. However the complex Cr(III) ions were bound to the sorbent surface via hydrogen bonds between the dye -OH groups and =O of the sorbent functional groups. The equation parameters of sorption isotherms indicate cooperative heterogeneous adsorption at low Cr(III) concentrations and chemisorption at high Cr(III) concentrations
EN
The surface modified Strychnos potatorum seeds (SMSP), an agricultural waste has been developed into an effective adsorbent for the removal of Zn(II) ions from aqueous environment. The Freundlich model provided a better fit with the experimental data than the Langmuir model as revealed by a high coefficient of determination values and low error values. The kinetics data fitted well into the pseudo-second order model with the coefficient of determination values greater than 0.99. The influence of particle diffusion and film diffusion in the adsorption process was tested by fitting the experimental data with intraparticle diffusion, Boyd kinetic and Shrinking core models. Desorption experiments were conducted to explore the feasibility of regenerating the spent adsorbent and the adsorbed Zn(II) ions from spent SMSP was desorbed using 0.3 M HCl with the efficiency of 93.58%. The results of the present study indicates that the SMSP can be successfully employed for the removal of Zn(II) ions from aqueous environment.
EN
A comparison was made of influence of physically adsorbed methylene blue (MB) dye on the physicochemical properties of Manisa-Akdere zeolite (natural zeolite) and zeolite modified with K and Ca (all samples treated with hydrogen peroxide before modification) using batch adsorption technique. After elementary characterization of this adsorbent, the effects were investigated of initial MB concentration, pH, contact time, stirring rate, adsorbent dosage and temperature on the selectivity and sensitivity of the removal process. A larger adsorption of the dye was observed for modified zeolite (42.7 mg/g) than for natural zeolite (28.6 mg/g) per gram of an adsorbent after all zeolite samples treated with hydrogen peroxide. Zeolite treated with H2O2 showed higher adsorption capacity than untreated zeolite samples. The Langmuir model (R2 values between 0.959 and 0.996) fitted the experimental data better than the Freundlich model (R2 values between 0.804 and 0.988). The adsorption process was found to be slightly influenced by adsorbent dosage, contact time and temperature. Optimum pH for adsorption of MB was found to be at 7. Adsorption equilibrium attained within 30 minutes. The sorption of MB increased slightly with rising temperature. In addition, adsorption values rose with modification Ca-Exchanged (after H2O2 treatment) > K-Exchanged (after H2O2 treatment) > Zeolite treated with H2O2 > Ca-Exchanged >K-Exchanged >Natural Zeolite.
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