Adsorption Capacity Of Clay Research Articles

A comparative study of the adsorption and desorption process of selected natural Albanian clays toward methomyl and dimethoate pesticides

Natural soil components, such as clays, have recently piqued interest because of their potential as pesticide adsorbents. This research work sheds light on the possibility of the application of natural Albanian clays as adsorbents for methomyl and dimethoate pesticides from aqueous solutions. Natural Albanian clays from the regions of Brari, Currila, Dardha, and Prrenjasi were employed in the study and were characterized by granulometric analysis and powder X-ray diffraction. Each clay's adsorption capacity and desorption behavior were investigated toward the chosen pesticides. Within 48 h of contact time, methomyl and dimethoate solutions with different concentrations were evaluated at 25 °C to see how the insecticide concentration affected the adsorption & desorption processes for each natural clay type. The experimental data were fitted to Freundlich, Temkin and Dubinin-Radushkevich isotherm like functions and the results showed the best correlation on Freundlich like adsorption isotherm for almost all cases. Brari clay performed better adsorptive properties toward dimethoate, followed by Dardha, Currila and Prrenjasi clays. The dimethoate adsorbed quantities varied from 0.250 mg/g for C = 0.200 g/L to 0.822 mg/g for C = 0.500 g/L. In comparison to Dardha and Prrenjasi clays, Brari and Currila clays exhibit longer saturation times and improved methomyl retention. In the first 2 h of contact, 96.5% of methomyl and 81% of dimethoate were desorbed from Brari clay. The adsorption process was also investigated employing pseudo first-order and pseudo second-order kinetic models, with the results indicating that all clay-pesticide systems studied demonstrated second-order kinetic behavior. Based on the studied desorption process, it is possible to impregnate clays with various insecticides in agriculture and completely control the quantities of the insecticide released.

Methylene blue test and adsorption capacity of clays

This article presents results of experimental measurements focused on an ability of clay to adsorb Methylene Blue dye. This adsorption capacity is determined by a methylene blue test. Adsorption capacity could be a specific characteristics of individual types of clay which are basic component of earth. Therefore, the methylene blue test could be a good method to identify the composition of an unknown earth. Composition of earth is very important for example for final properties of unfired earth structures. The basic common element in all experiments was at least one of the elementary clay minerals (montmorillonite, kaolinite, illite). In the case of adsorption ability measurements, it was determined what is the maximum ability of a given clay to adsorb the Methylene Blue dye. The highest adsorption capacity was determined for montmorillonite clay, lower for kaolinite clay and the lowest for illite clay.

Removal of Acid Red 88 from an Aqueous Solution Using Kaolinite Clay by Adsorption Process

Dyes are hazardous contaminants normally found in industrial wastewaters necessitating costly and complex technologies for their removal. In this study, clay was used as an adsorbent in the removal of anionic acid red 88 (AR 88) dye from industrial wastewaters by adsorption. The dye removal efficiency and adsorption capacity of clay was studied by batch experimentation with respect to parameters of dye initial concentration, clay dosage, contact time, and pH. The dye removal efficiency of AR 88 improved with increasing dosage (r 0.9826, p < 0.05), contact time (r 0.9821, p 0.000683) and decreased with increasing initial concentration (r - 0.9168, p 0.02844) and pH (r -0.9666, p 0.007297) of the solution. At initial AR dye concentration of 100 mg/L, the removal efficiency and adsorption capacity of 89.7% and 4.38 mg/g, respectively were achieved after equilibrium time of 30 minutes under the optimum conditions of pH 2 and clay dosage 20 g/L. The study thrived in applying an efficient and low-cost adsorbent that could be used as a substitute to high-cost conventional commercial adsorbents in treating industrial wastewater with AR dye coloration

Kinetics and Isotherm Study of Ion Phosphate Adsorption by Lontor Natural Clay

The clay used taken from Lontor Village, Central Maluku Regency, Banda Besar Island. The clay was activated at 350 °C for 3 hours using a furnace. This study aims to determine the effectiveness of physically activated Lontor natural clay in reducing levels of phosphate ions using the adsorption method. The adsorption capacity of clay is determined based on two parameters. The parameters are the optimum contact time used are 2, 3, 4, 5, and 6 hours and variations of the concentration are 10, 20, 30, 40, and 50 mg/L of phosphate. The concentration of phosphate adsorbed on the clay was measured by a UV-Vis spectrophotometer at a wavelength of 665 nm. The results showed that the optimum conditions for the adsorption of phosphate ions by Lontor natural clay were obtained at the contact time of 5 hours and the concentration of 40 mg/L. The adsorption of phosphate ions by Lontor activated natural clay followed the pseudo-second-order Lagergren adsorption kinetics model with a rate constant value (k2) of 3.39 x 10-1 g mg-1 min-1, and following the Freundlich adsorption isotherm models with a correlation coefficient (R2), Freundlich constant (Kf), and n values, respectively are 0.9513; 0.57 mg1-1/n L1/n/g, and 0.40 g/L.

Kinetic and thermodynamic study on adsorption of cadmium from aqueous solutions using natural clay

Heavy metal pollution poses a great risk for the environment and the human health. Cadmium is among the most common pollutants found in wastewater, known for its great toxicity even in small doses. This work aims to study the removal of cadmium using natural Moroccan clay (MC). The clay was characterized using X-ray diffraction, X-ray fluorescence, Fourier transform infrared spectroscopy, BET, and SEM. The effects of several experimental parameters on the clay adsorption capacity towards cadmium ions, such as MC dose, initial concentration and contact time, initial pH, and temperature were studied. The kinetic models Pseudo-first order, Pseudo-second order, and Elovich are evaluated to identify the adsorption process. The adsorption mechanism was determined by the use of the adsorption isotherms: Langmuir, Freundlich, and Temkin model. The results show that the heavy metal retention obeys the Pseudo-second order (R²≥0.99). The Langmuir isotherm model provided the best fit (R²≥0.99) to the experimental data for the adsorption of Cd(II) by MC as compared to the Freundlich and Temkin model. The maximum monolayer adsorption capacity of Cd(II), using the Langmuir model equation, is equal to 5.25 mg/g. The adsorption is a spontaneous and an endothermic process characterized by a disorder of the medium.

Chemical and thermal activation of clay sample for improvement adsorption capacity of methylene blue

ABSTRACT In this study, the removal of methylene blue (MB) by both raw and modified clay as an abundant, cost-effective was investigated. The modification of the raw clay was done by calcination, acid treatment, and again second calcination processes. In addition, the effects of calcination temperature and acid/base concentration on the adsorption capacity of clay were investigated. The characterisation of clay was performed by scanning electron microscopy (SEM) and Fourier transformed infrared spectroscopy (FTIR) analyzes. Langmuir and Freundlich isotherm models were used. The modified clay provided significant improvements in adsorption capacity compared to the raw clay.

INFLUENCE OF EARTH COMPOSITION ON ADSORPTION CAPACITY OF METHYLENE BLUE DYE

Final properties of unfired earth are influenced by composition of earth mixtures. Methylene blue test could be useful method for analysis of earth composition. This would facilitate of designing unfired earth building structures because composition of natural earth is various. Principle of methylene blue test is measure of amount of adsorbed methylene blue dye by clay. The essential component of earth mixtures is clay because clay fulfils a function of binder. Experimental measure of adsorption capacity of individual kind of clay is described in this paper. Adsorption capacity was investigated in montmorillonite, kaolinite, illite-kaolinite and illite clays. The obtained results show that the adsorption capacity of clays is significantly different.

Optimization of Ni(II) adsorption onto Cloisite Na+ clay using response surface methodology.

The aim of this study was to investigate the adsorption of Ni(II) from aqueous solutions onto Cloisite Na+ clay. The effects of the initial concentration of Ni(II), adsorbent dose, pH, and temperature on adsorption capacity were studied using response surface methodology. A second-order regression model was determined based on the experimental results. Analysis of variance used to evaluate the individual and combined effects of process variables showed that initial Ni(II) concentration and adsorbent dose were more significant than solution pH and temperature. Moreover, the interaction effects of the initial concentration of nickel and the adsorbent dose, as well as the solution pH and adsorbent dose were significant. High coefficient of determination (R2=0.93) and low probability values signify the validity of the model for predicting the adsorption capacity of Cloisite Na+ for Ni(II) ions. The optimal conditions for pH and adsorbent dose were found to be 6.9 and 0.21g/L, respectively at a constant temperature of 25°C and initial Ni(II) concentration of 50mg/L. Under these conditions, the adsorption capacity of clay was found to be 31.43mg/g. Moreover, the adsorption isotherms results indicated that these data could be best fitted to the Langmuir isotherm model (R2=0.99). The Langmuir maximum adsorption capacity was estimated to be 32.05mg/g for an adsorbent dose of 0.2g/L at pH 7 and 25°C. In conclusion, the results showed that Cloisite Na+ clay can be utilized as an effective adsorbent for the removal of Ni(II) from aqueous solutions.

Fabrication of a sustained release delivery system for pesticides using interpenetrating polyacrylamide/alginate/montmorillonite nanocomposite hydrogels

In pest control field, the sustained release of pesticides plays significant roles in effectiveness and environment friendly. In this study, the sodium alginate (SA), polyacrylamide (PAM) and montmorillonite (MMT) were utilized to fabricate the stretchable double-network nanocomposite hydrogel, which apply in a sustained release system of acetamiprid. These nanocomposite hydrogels were fully characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The results indicate that adding MMT could significantly improve the sustained release performances of the hydrogels. The swelling behavior of all the hydrogels well fits into the Fickian diffusion model. The hydrogel with 5.0% MMT content shows the maximum pesticides loading rate of 13.32% and minimum pesticides release rate of 76.11%. The nanocomposite hydrogels take advantages of both the gelation property of alginate and the adsorption capacity of clays, has great potential in the application of pesticides carrier to improve the utilization efficiency of water-insoluble pesticides.

Adsorption kinetics and molecular interactions of lead [Pb(II)] with natural clay and humic acid

Currently, the contamination by lead has become a serious issue to the environment, and many approaches are continuously been searched for its removal from the environment. In the present study, the adsorption potential and interaction of lead [Pb(II)] with natural clay and humic acid were investigated. X-ray diffraction analysis revealed quartz as a dominant mineral in natural clay. Maximum adsorption capacity of both natural clay and humic acid for Pb(II) was 25.07 and 19.16 mg/g, respectively, after the incubation time of 180 min and adsorbate and adsorbent concentrations of 20 mg/L and 10 g/L, respectively. Adsorption capacity of clay was found to be 1.3-folds greater than that of humic acid. Pb(II) adsorption on clay and humic acid was according to the Langmuir isotherm and followed the pseudo-second-order and intraparticle diffusion model kinetics. Fourier transform infrared spectra revealed that Si–O–Si and OH− groups in clay were involved in the interaction with Pb(II); and carboxylic acid, phenolic and alcoholic groups and alkyl halides in humic acid were involved in the interaction with Pb(II). Scanning electron microscopy and energy-dispersive X-ray spectra analysis revealed that Pb(II) adsorption on clay and humic acid occurred by replacement of Mg and Al ions, potentially by ion exchange mechanism. Overall, the results concluded that natural clay and humic acid are promising adsorbents for limiting the mobility of Pb(II) ions in the soil system and aquatic environment, and this could be an effective method for lead waste management.

Stretchable hydrophobic modified alginate double-network nanocomposite hydrogels for sustained release of water-insoluble pesticides

In agritechnology applications, the sustained release of pesticides plays significant roles in efficient bioavailability and environmental protection. In this study, hydrophobic derivate of sodium alginate (Ugi-SA), polyacrylamide (PAM) and montmorillonite (MMT) were utilized to construct several stretchable double-network nanocomposite hydrogels, which were used to control the release of λ-cyhalothrin. These nanocomposite hydrogels were fully characterized by Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The adoption of Ugi-SA and appropriate incorporation of MMT could significantly improve the tensile properties, pesticide-loading efficiency and sustained release performances of the hydrogels. The swelling behavior of all the hydrogels well fits into the Fickian diffusion model. The maximum fracture strain and loading efficiency of the hydrogels reached 2000% and 81.30%, respectively. The hydrogel with 5% MMT content shows the lowest cumulative release percentage of 6.68% over 87 h, and the pesticide release curves well fit into the Weibull model. These novel nanocomposite hydrogels take advantages of both the gelation property of alginate derivatives and the adsorption capacity of clays, to serve as promising potential carriers and to improve the utilization efficiency of water-insoluble pesticides.

Phosphorus buffering capacity of substrate clays and its significance for plant cultivation

AbstractPeat is commonly used as the main component of horticultural substrates, but it has a very low buffering capacity for the anionic macronutrient phosphorus (P), which can be increased by the addition of clays. The aim of this study was to characterize the P adsorption capacity of different substrate clays and to evaluate its significance for plant P uptake. Substrate clays were characterized with a single‐point batch experiment and adsorption and desorption isotherms. The data were fitted to the Langmuir equation for a calculation of the maximum adsorption capacity. Additionally, the contents of oxalate extractable Fe and Al (ΣFeox + Alox) were determined. The influence of a varying P adsorption capacity of the clays on the P availability to plants in the respective peat–clay substrates and pure peat was investigated in a growth experiment with Impatiens walleriana fertigated with 0, 17, and 35 mg P L−1 solution, respectively.The observed and calculated (Langmuir) P adsorption capacity of the clays could be well‐characterized by both the batch experiment and the adsorption isotherms and was highly correlated with the ΣFeox+Alox. A higher P adsorption capacity of the clay amendment in mixed substrates resulted in a lower P concentration in the substrate solution, while the CAT extractable P concentration (PCAT) was the same. Plant growth and shoot P concentrations were enhanced in the substrates, showing a higher P adsorption capacity, since plants were able to take up the whole amount of PCAT, and also part of the non‐CAT extractable P. However, the release rate was too low to ensure optimal plant growth, which was in accordance with the result of the desorption experiment. The absolute extent of P release was increased with the increasing P adsorption capacity of the clays and higher degree of P saturation (DPS).

Adsorption of anionic dyes onto natural, thermally and chemically modified smectite clays

Abstract The aim of this study was to determine the adsorption capacity of the smectite clays (from the overburden of the lignite deposit in Belchatow) for two anionic dyes, i.e. Reactive Blue 81 (RB-81) and Direct Blue 74 (DB-74). Additionally, the influence of the thermal and chemical (acid and alkali) clay modifications on the amount of bonded dyes was investigated. The adsorption capacity of the clay (natural and modified) was different for studied dyes and depended on the initial concentration and modification type. All the modified clays adsorbed the dyes at pH>pHPZC as the negatively charged surfaces of their particles (in accordance with the formula: AOH ↔ AO- + H+) prevented the formation of electrostatic bonds between the anionic dyes and the clay surface. The dyes were mainly bound with the hydrogen bonds forming between the donor groups in the dyes and the acceptor groups (-SiO and -Al2OH) in the clays. The coefficients in the adsorption isotherms were estimated with the linear and non-linear regression. The linear regression method was found that the Freundlich and Dubinin-Radushkevich isotherms described the dye sorption much better than the Langmuir model. On the other hand, all three models described well the experimental data in the non-linear regression method. Furthermore, the 1/n value (<1) obtained from the Freundlich equation for all the dye-sorbent systems indicated the favorable sorption.

Sorption Behaviour of 137Cs on Kaolinit

The aim of this study was to carry out a systematic investigation of the adsoption of 137Cs on to Kaolinite clay mineral from Balikesir region which is west of Turkey. The adsorption behavior of kaolinite mineral was studied by means of a batch method using 137Cs as a radio tracer. Experiments were carried out for clay size of 30.00 μm and six different initial concentrations of 137Cs. In experiments, solid/ liquid ratio and contact time were determined to be 250 mL/g and 60 minutes, respectively. Adsorption percent (Ads%) and distribution coefficient (Kd) values were calculated according to the adsorption experiment results. After Langmuir Isotherm was applied, the clay adsorption capacity was calculated using Least Squares Method. It was observed that Ads% and Kd values decreased with increasing the liquid phase concentrations ranging from 1.68x10-4 M to 5.88x10-4 M. The constants depending on adsorption energy (b), adsorption capacity (Xm), and removal efficiency (R) were determined to be 17.56×103 mg/kg, 0.038 L/g and 93%, respectively. Kaolinite was found to be having both a good adsorption capacity and a rapid adsorption rate for 137Cs.

Removal of chromium (VI) ions from aqueous solutions by using Turkish montmorillonite clay: effect of activation and modification

This study provides information on the Cr(VI) adsorption potential of Turkish (Mihalıççık region) montmorillonite clay as an abundant, cost-effective and untried material. Batch adsorption trials of chromium were performed to investigate the effects of pH, contact time, and initial metal ion concentration. The adsorption was solution pH dependent and the maximum adsorption was observed at a solution pH of 1.0. Adsorption equilibrium was established in 7 h. Langmuir, Freundlich and Dubinin–Radushkevich isotherm models were used to evaluate the equilibrium data at 20°C and regression coefficients were derived. Adsorption kinetics was analyzed using the firstorder and the pseudo-second-order kinetic models. Also, the effects of activation and modification on the adsorption capacity of clay were investigated under optimum conditions. Adsorption capacity of modified clay with hexadecyltrimethylammonium bromide was higher than that of acid and heat treated ones.

Elimination du Carbendazime Contenu dans des Eaux de Conditionnement de Fruits par Adsorption sur Differents Materiaux Removal of Carbendazim from Fruit Conditionning Waters by Adsorption on Different Materials

The main aim of this work is to test different materials (activated carbon and other more “rustic” materials like clay and coal) as potential adsorbents in order to evaluate their adsorption capacity for carbendazime. The experiments were realized with certified carbendazim or with benlate solutions left to change long enough to suppose all the benomyl converted into carbendazim. The results were introduced through adsorption kinetic and isotherm forms or interpreted according to the Langmuir model. They pointed out that final elimination percentages of certified carbendazim don't exceed 55%. But even the activated carbon remains the most effective adsorbent, clay and coal present an interesting adsorption capacity, 45% for clay (but its performance is varied), 35% for coal. The presence of formulation additives has an inhibitive effect whatever the materials is. Some adsorption attempts with clay and coal mixtures (100 mg l-1 of each one) were realized, there isn't a cumulative adsorption, final percentages of elimination are about 45%. Characterization attempts of the adsorbents pointed out that all the materials have a negative global surface charge. But clay possesses a surface charge far more negative than coal, sodipolary lap of carbendazim can further the adsorption. The measures of surface functions according to Boehm titration and capillary rising technique showed that coal differentiates from the other materials by its high capacity to establish Lifshitz-Van der Waals interactions. Carbendazim molecule can present a dipolary moment which could lead to the formation of hydrogen bonds. But results of capillary rising are to be considered by surface unities that could explain the superior adsorption capacity of clay (internal surface: 800m2 g-1).

Development of a biofilter for turbid and nitrogen-rich irrigation water; B: Removal of phosphorus, algae and clay

A biofilter made out of chopped wheat straw was shown to be an effective system to remove nitrogen from waste-water, both due to nitrogen immobilization as well as to a nitrification-denitrification sequence (Lowengart, A., Diab, S., Kochba, M. & Avinmelech, Y. 1993. Development of a biofilter for turbid and nitrogen-rich irrigation water. A: Organic carbon degradation and nitrogen removal processes Bioresource Technol. 44, 131-5). The tested laboratory scale biofilter was made out of wheat straw, a substrate that has excellent hydraulic characteristics. The pores are large and the substrate has a very high hydraulic conductivity and a very low sensitivity to clogging. Yet, it has, apparently, a high reactive and effective surface area. Thus, it can be easily used for the biofiltration of turbid water. The removal of phosphorus, clay and algae by the same biofilter is reported in this paper. Phosphorus was taken up by the growing microbial biomass, probably in parallel to the nitrogen immobilization process. Clay was removed very effectively from the water, due to its adsorption on the mucilaginous biofilm that developed on the degraded straw. The clay adsorption capacity was more than 170 mg clay/g straw. The removal of algae was also very effective. Moreover, the adsorbed algae provide an additional, ‘ever-lasting’ source of available organic carbon rich substrate, leading to the continual functioning of the biofilter. The straw biofilter seems to be an inexpensive, simple and efficient biofilter to reduce the levels of nitrogen, phosphorus, clay, algae and organic carbon in waste water used for irrigation.

Investigation of Nickel Ion Removal by Means of Activated Clay

Natural and activated clays have been investigated as adsorbents for the removal of nickel from wastewater. Analysis of the natural clay under test showed that it was composed, approximately of 51% kaolinite, 46% montmorillonite and 3% illite, having a specific surface area of 65 m2/g. The natural clay was treated with different activators (HCl, NaCl and H2O2) to enhance its adsorption capacity towards nickel. The efficiency of such activation was greater by 16.0% and 23.2% in the case of NaCl and H2O2, respectively, relative to untreated clay. No significant increase in the adsorption capacity was brought about by HCl treatment. A limited comparison has been made between clay and activated carbon by performing isotherm studies under similar conditions. The results indicate that the adsorption capacity of clay activated with H2O2, clay activated with NaCl and natural clay is 216.9%, 204.2% and 176.1% that of activated carbon, respectively. Based solely on the adsorption capacity, an economic analysis demonstrates that natural clay is the cheapest material, followed by clay activated with NaCl and clay activated with H2O2. The relative costs of removing nickel using natural clay, clay activated with NaCl and clay activated with H2O2 were found to be 2.8%, 5.4% and 25.4%, respectively, that of activated carbon.