Tempkin Isotherm Research Articles

Synthesis and characterizations of a novel hydrogel for adsorptive removal of crystal violet dye from wastewater

Herein, a novel hydrogel (HG-cl-poly(AA)) was synthesized by grafting acrylic acid (AA) onto Hing gum (HG) using methylene-bis-acrylamide (MBA) as a cross-linker and ammonium persulfate (APS) as an initiator in a hot air oven. The percentage swelling of the hydrogel was examined by optimizing various reaction parameters to ensure its maximum swelling percentage. The formation of crosslinked networks was confirmed using Fourier-Transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and thermogravimetric analysis (TGA) techniques. The surface area and hydrophilicity of the prepared hydrogel were determined using Brunauer–Emmett–Teller analyzer and wettability studies, demonstrating a clear correlation with adsorption. The adsorption of crystal violet (CV) dye on the prepared hydrogel was studied via a batch adsorption system based on the amount of adsorbent, immersion time, pH level, and initial dye concentration. The prepared hydrogel showed a 99% removal rate and an excellent adsorption capacity of 492.61[Formula: see text]mg/g due to the electrostatic, H-bonding, and dipole–dipole interactions between the adsorbent surface and dye molecules. The results were further analyzed using the Langmuir, Freundlich, and Tempkin isotherm models. The study suggests consistency with the pseudo-second-order kinetic model ([Formula: see text]), further supported by the best data fit with the Langmuir isotherm model ([Formula: see text]). The thermodynamic study results indicated that the adsorption process is endothermic and spontaneous. Regeneration (desorption) studies showed that the prepared hydrogel could remove CV dye from an aqueous solution and maintain the highest adsorption capacity even after multiple adsorption and desorption cycles. Therefore, the prepared HG-cl-poly(AA) hydrogel could be a potential adsorbent for dye removal and have an admirable capacity for cleaning the aquatic environment.

Nickle(II) and cobalt(II) ion removal using electrospun β-cyclodextrin/grafted-chitosan nanofibers as efficient molecular filters

Considering the gradual depletion of water resources, developing smart molecular filters targeting heavy metal ion removal is necessary. Herein, β-Cyclodextrin (β-CD) was coupled with chitosan (CS) to yield β-cyclodextrin/grafted-chitosan, which was subsequently electrospun to form nanofibrous membrane (β-CD-g-CS/PVAnfm). The sample was certified using FT-IR, 1H NMR, XRD, SEM, and EDX analyses. β-CD-g-CS/PVAnfm receives the combined features of both CS and β-CD, including size specificity, host-guest complexation properties of β-CD, and the chelation ability of CS, along with the fascinating advantages of nanofibers, which synergistically amplifies ion adsorption. The outstanding features of β-CD-g-CS/PVAnfm as a molecular filter were investigated by measuring the absorbance of Ni(II) and Co(II) ions using atomic absorption spectroscopy. β-CD-g-CS/PVAnfm exhibited remarkable efficacy in absorbing Ni(II) and Co(II) ions, with a maximum adsorption capacity of 154 mg/g and 160 mg/g, respectively. Isotherm studies revealed the superior fit of Freundlich and Tempkin isotherms for Ni(II) and Co(II) ions, respectively, while kinetic data align with the pseudo-second-order model. These results demonstrate the outstanding heavy metal ion removal capacity of β-CD-g-CS/PVAnfm, rendering treated water safe for reuse. While acknowledging techno-economic challenges in electrospinning, we suggest exploring electrospinning in liquid media as a roadmap for future research.

Synthesis and spectroscopic characteristics of chitosan composite of zinc-based metal-organic framework for rapid adsorption of organic pollutants from aqueous media

ABSTRACT The efficiency of the metal-organic framework of zinc (MOF-74) and its chitosan composite (CS/MOF-74) as a potential sorbent for the elimination of azo in addition to thiazine-type dyes from water by subsequent adsorption was studied. The synthesized adsorbents were characterized by various characterization techniques. The chitosan composite exhibited tremendous adsorption properties toward methyl orange (MO) and methylene blue (MB) at pH < 5.5 and pH > 5.5, respectively. The equilibrium data were evaluated by Dubinin-Radushkevich, Langmuir, Freundlich, and Tempkin isotherm models where the Langmuir model was best fitted to the adsorption data. The mono-layer sorption capacity values were found to be in the order 2047 mg/g and 1363 mg/g for MO and MB respectively onto CS/MOF-74 which are almost 6–8 epochs superior to MOF-74 and CS. In addition, pseudo-first, pseudo-second, intraparticle diffusion and Richenberg kinetic models were assessed to the kinetic data where the pseudo-second-order fitted very well to the adsorption data. The higher values of diffusion coefficient confirmed the greater involvement of the film diffusion than the pore and surface diffusion for the elimination of basic as well as acidic dyes onto CS/mOF-74. Thermodynamically, the negative value of isosteric heat of adsorption (Δ H ˉ ) concluded that the current study was found exothermic in nature. Moreover, electrostatic interactions, hydrogen bonding, and electron donor–acceptor interactions were suggested as probable mechanisms in the current adsorption process. The current study estimates the industrial importance of a chitosan composite of MOF-74 as it requires a short adsorption equilibrium time for the removal of the dyes and is satisfactorily reusable.

Okra-psyllium based green synthesis of eco-friendly bio-adsorbent for efficient removal of uranium and crystal violet dye from aqueous media: statistical optimization using response surface methodology

Abstract The prime objective of this study is to synthesize eco-friendly okra-psyllium based hydrogel through free radical crosslinking method by using citric acid-ammonium persulfate as a crosslinker-initiator system. Various techniques were used to explore the morphology, structure and thermal behaviour of the synthesized hydrogel via. Powdered X-ray diffraction studies, SEM and TGA techniques. Response surface methodology was performed to maximize the grafting percentage of the synthesized hydrogel up to 244 % and swelling percentage of 598 %. The physicochemical properties like salt-resistance behaviour and the impact of ionic strength on the swelling percentage of synthesized hydrogel were investigated and thus observed with the following trend as K+ &gt; Ca2+ &gt; Fe3+. Furthermore, the synthesized sample showed an excellent bio-adsorbent behaviour for the removal of uranium with 97.75 % removal in 60 min and crystal violet dye removal up to 85.32 % in 24 h from contaminated water. Various kinetic and isotherm adsorption modelling were implied to probe the mechanism of adsorption with displayed interactions between the absorbate and the absorbent. The Langmuir isotherm model was well-fitted in dye adsorption case with regression co-efficient value of 0.99. In case of uranium, tempkin isotherm model was best fitted with regression co-efficient value as 0.92. Crystal violet dye adsorption favoured second-order kinetic model whereas the adsorption mechanism of uranium followed first-order kinetics. Hence, the revealed results depicted that the synthesized hydrogel served as a potential candidate for the effective removal of toxic dye (crystal violet) and metal ion (uranium) from aqueous media with a sustainable approach towards environment.

Adsorption of toxic dye using red seaweeds from synthetic aqueous solution and its application to industrial wastewater effluents

This study investigated the potential application of dried powder from red seaweed Pterocladia capillacea as an eco-friendly adsorbent for removing Crystal Violet Dye (CV dye) from a synthetic solution. The adsorption conditions for the adsorbent were determined, in batch conditions, by changing different experimental parameters such as initial CV dye concentrations (5, 10, 20, 30, and 40 mg L–1), contact time (15, 30, 60, 120, and 180 min.), adsorbent doses (0.025, 0.05, 0.1, 0.2, and 0.3 g), temperature (25, 35, 45, and 55°C), and pH (3, 5, 7, 9, and 11). The adsorption mechanisms of CV dye onto the P. capillacea biomass were examined using various analytical techniques such as FTIR, BET, UV–Visible, and SEM. These characterizations suggest the average BET surface area of P. capillacea was 87.17 m2 g–1 and a pore volume of 0.10368 cc g−1. Moreover, according to the FTIR study, the dye has been deposited inside the adsorbent’s pores after adsorption. The adsorption behavior of the adsorbent was investigated by performing both kinetic and equilibrium isothermal studies in batch conditions at 25°C. Also, the thermodynamic factors showed the exothermic nature and physisorption of the adsorption process, which tends to be spontaneous at lower temperatures. In addition, Langmuir, Dubinin-Radushkevich, Freundlich, and Tempkin isotherm models were selected to evaluate the adsorption of CV dye on P. capillacea. The equilibrium adsorption data were best represented by the Freundlich, indicating multilayer adsorption on the heterogeneous surface. The qe experiment and calculation values for the Pseudo-Second-Order and interparticle diffusion kinetic models were determined. The results showed that, under optimum conditions P. capillacea exhibited 98% removal of CV dye from synthetic wastewater. Moreover, it will help to regenerate the adsorbents that can be reused to adsorb CV dye ions and develop a successful adsorption process. Finally, this study concluded that the dried powdered form of P. capillacea is an attractive source for adsorbing CV dye from aqueous solution.

Pineapple peel–derived carbon for adsorptive removal of dyes

The pineapple peel activated carbon (PiPAC) showed remarkable adsorption capacities for methylene blue (MB) and methyl red (MR) dyes as a result of its high porosity. Characterization techniques, including Thermogravimetric analysis (TGA), Brunauer–Emmett–Teller (BET), X–ray diffraction analysis (XRD), Fourier Transform Infrared (FTIR), Energy–dispersive X–ray spectroscopy (EDX), and Scanning Electron Microscopy (SEM) were employed to analyze the PiPAC's performance. The EDX examination revealed that the PiPAC (BET surface area: 1160 m2/g) contained 67.18% of the carbon supported by PiPAC's functional group and XRD crystallization. Results showed the highest maximum adsorption capacity (qmax) for PiPAC–MB dye at 165.17 mg/g (pH 8) and PiPAC–MR dye at 94.87 mg/g (pH 6) at 60 °C. The Langmuir, Freundlich and Tempkin isotherm for PiPAC–MB and PiPAC–MR dyes fitted the equilibrium isotherm studies. The PiPAC–MB dyes were found to suit the PSO kinetic model, whilst the PiPAC–MR dyes fitted the PFO kinetic model and were in excellent agreement with the experimental findings. The thermodynamic behaviour showed endothermic, physisorption–mediated, and spontaneous adsorption of PiPAC–MB and PiPAC–MR dyes. The regeneration efficiency of PiPAC showed higher in the third cycle, 75.6% for the MB dye supported with FTIR spectra, EDX spectra and SEM. Molecular docking studies also revealed that van der Waals, π–π stacking, and hydrogen bonding interactions were involved in the adsorption of PiPAC–MB and PiPAC–MR dyes. Thus, pineapple waste, a conventional environmental liability, can be transformed into valuable adsorbents for wastewater treatment.

Heavy Oil Fly Ash as an Adsorbent for Methylene Blue Removal from Aqueous Solution

The industry produces a large amount of solid waste that has very bad effects on the environment. The application of waste material adsorbents for waste materials treatment has become of greater interest. Heavy oil fly ash (HOFA) is hazardous industrial solid waste which produces from the combustion of heavy fuel oil in power plants. The work aims to investigate using waste material heavy oil fly ash (HOFA) after modification to activated carbon (AC) as an adsorbent of methylene blue (MB) in an aqueous solution. Chemical and physical analyses were conducted to characterize the HOFA produced as a by-product of an electrical power station. BET analysis showed the surface area was 1.6 m2/g and the surface area was enhanced by the activation process to 63.7 m2/g and the pore width to 553.5A. SEM showed a change in the nature of the surface of the martial by increasing the porosity. Adsorption studies were performed by batch experiments as a function of process parameters. The removal percentage increased with the increase of the adsorbent to 1.5g, the amount was selected as the optimum dosage. The removal percentage decreased with an increase the entail dye concentration and limited difference in pH variables. The experimental adsorption data was represented with Langmuir, Freundlich, and Tempkin isotherms. The data fitted well to the Freundlich model as multilayer adsorption.

Evaluation of Heavy Metal Removal of Nanoparticles Based Adsorbent Using Danio rerio as Model.

Nanoparticles are potential candidates for wastewater treatment especially for the removal of heavy metals due to their strong affinity. Many biopolymers are used as adsorbents and encapsulation of nanoparticle onto them can increase their efficiency. In this study, SPIONs, alginate, and SPIONs incorporated on alginate beads have been synthesized and characterized both microscopically and spectroscopically. These were then used for the removal of chromium metal and the percentage of removal was evaluated using a batch adsorption study. The percent removal of chromium using SPIONs, alginate and alginate-SPIONs beads were recorded to be 93%, 91% and 94%, respectively. The adsorption of chromium using SPIONs and alginate-SPIONs beads followed the Tempkin isotherm, whereas adsorption of chromium metal by alginate beads was found to be homogeneous in nature and followed the Langmuir isotherm with an R2 value of 0.9784. An in-vivo study using Danio rerio as a model organism was done to examine the toxicity and the removal efficiency of the samples. It was observed that chromium water treated with alginate-SPIONs beads, which were removed after water treatment showed less damage to the fishes when compared to SPIONs and alginate beads treated with chromium water where the SPIONs and alginate beads were not removed after the treatment period.

Bio-sorption of Methylene Blue by Defatted Seed of Adansonia digitata

The study was carried to evaluate the ability of defatted seed of Adansonia digitata (DFSE) to remove methylene blue dye from contaminated water. The optimum parameters such as contact time, particle size, absorbent dose, initial dye concentration, and pH were investigated by performing batch experiments models. The kinetics and the isotherms adsorption were evaluated by varying the initial concentration and using the optimum parameters. The optimum of contact time is 90 min and the removal capacity is 99.34 %. A mass of 700 mg is sufficient to reach the maximum removal of methylene blue (99.44 %). The maximum adsorption is obtained with an initial methylene blue concentration of 75 ppm (98.53 %). The optimum particle size is 100 mm. The kinetics of the adsorption process are in accordance with the pseudo-second order model. Experimental values of the adsorption capacity are close proximity to the optimum values predicted by the pseudo-second order model. The Langmuir, Freundlich, Dubinin-Radushkevich and Tempkin isotherms are not suitable to explain the experimental isotherm.

Removal of Tetracycline from aqueous solution using composite adsorbent of ZnAl layered double hydroxide and bagasse biochar

A new composite adsorbent of biochar derived from bagasse and ZnAl-layered double hydroxide was produced by the in-situ growth method. The prepared biochars were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) analysis, the Brunauer–Emmett–Teller (BET) isotherms, Scanning electron microscopy (SEM), Energy Disperse X-ray (EDX) spectroscopic and Mular–Roberts titration analyses. The best Zn:Al molar ratio for the ZnAl-LDH/BGC composite to adsorb tetracycline was 3:1. The specific surface area of ZnAl-LDH/BGC31 was 456.39 m 2 /g compared to 404.05 m 2 /g for BGC. The optimal pH, contact time and initial TC concentration for TC adsorption were 6.0, 120 min and 25 mg/L, respectively. The ZnAl-LDH/BGC31 had a maximum adsorption capacity ( q m ) of 41.98 mg/g. The obtained data were analyzed with Langmuir, Freundlich and Tempkin isotherm models. Kinetic data were evaluated by using pseudo-first and pseudo-second-order kinetic models. The adsorption mechanism of ZnAl-LDH/BGC31 to remove TC was likely based on the pore-filling process, electrostatic attraction and π − π conjugate effect. ZnAl-LDH/BGC31 had significant adsorption capacity after five reusabilities. • ZnAl-layered double hydroxide bagasse biochar compositered (ZnAl-LDH/BGC31) was synthesized. • The maximum adsorption capacity ( q m ) of TC (41.98 mg/g) at pH 6 and 25 mg/L of initial TC. • Isotherm and kinetic model fitting indicated physisorption and chemisorption of TC. • The pore-filling process, electrostatic attraction and π − π conjugate effect were critical role in TC adsorption. • ZnAl-LDH/BGC31 adsorbent maintained its high adsorption ability up to 5 reusability.

Equilibrium and Kinetic Modeling of Crystal Violet Dye Adsorption by a Marine Diatom, Skeletonema costatum.

Significant efforts have been made to improve adsorbents capable of eliminating pollutants from aqueous solutions, making it simple and quick to separate from the treated solution. In the current study, the removal of Crystal Violet Dye (CVD) from an aqueous synthetic solution onto a marine diatom alga, Skeletonema costatum, was investigated. Different experiments were conducted as a function of different pH, contact time, adsorbent dosage, temperature, and initial CVD concentration. The highest adsorption efficiency (98%) was obtained at 0.4 g of S. costatum, pH 3, and a contact time of 120 min, at 25 °C. Furthermore, Fourier-transform infrared spectroscopy (FTIR) results display that binding of CVD on S. costatum may occur by electrostatic and complexation reactions. Moreover, the Brunauer–Emmett–Teller surface area analysis (BET) obtained was 87.17 m2 g−1, which, in addition to a scanning electron microscope (SEM), reveals large pores that could enhance the uptake of large molecules. However, the equilibrium adsorption models were conducted by Halsey, Langmuir, Freundlich, Henderson, and Tempkin isotherm. In addition, multilayer adsorption isotherm best described the uptake of CVD onto S. costatum. The maximum monolayer adsorption capacity (qmax) was 6.410 mg g−1. Moreover, thermodynamic parameters of the adsorption studies suggested that the uptake of CVD onto S. costatum was endothermic and spontaneous. The pseudo-first-order, pseudo-second-order, and intra-particle diffusion kinetic equations were applied to model the adsorption kinetic data. It was seen that the kinetics of the adsorption may be described using pseudo-second-order kinetic equations. Finally, the present work concluded that the marine diatom alga S. costatum is suitable as a natural material for the adsorption of CVD.

Thermodynamic and electrochemical investigation of inhibition efficiency of green corrosion inhibitor and its comparison with synthetic dyes on MS in acidic medium

The expedition of Green corrosion inhibitors has been initiated by the organic corrosion inhibitor as green corrosion inhibitors are bio-degradable, eco-friendly and environmental acceptable bereft of heavy metals and other toxic products. Moreover, the products obtained from the plant are cost-effective, readily available and can be renewed. In the following study, the inhibition performance of natural inhibitor i.e., black pepper extract and synthetic inhibitors i.e., thoron Dye and Phenosafranin dye on mild steel surfaces in hydrochloric acid (HCl) were inspected and for this purpose, weight loss measurements, Electrochemical Impedance Measurements (EIS) and Potentiodynamic Polarization study at different concentrations and at different temperatures were recruited. Among these inhibitors, the best inhibition efficiency was shown by black pepper extract i.e., 97% in 1 M HCl. In the prolongation of our work, entropy (ΔS), enthalpy (ΔH), gibbs free energy (ΔG), activation energy (Ea) and pre-exponential factor (A) of the reaction were calculated and it is concluded that the inhibition process follows physical adsorption on the surface and the adsorption process follows Langmuir and Tempkin isotherms also. For surface analysis, Atomic Force Microscopy (AFM) was done. The present study concludes that natural inhibitor i.e., Black pepper extract which contains alkaloid piperine becomes quite impressive in decelerating the effect of corrosion on mild steel surfaces in acidic environments as compared to synthetic inhibitors.

Cladium mariscus Saw-Sedge versus Sawdust—Efficient Biosorbents for Removal of Hazardous Textile Dye C.I. Basic Blue 3 from Aqueous Solutions

Bio-based waste materials are more often used as effective and cheap adsorbents to remove toxic organic compounds such dyes. Batch adsorption of C.I. Basic Blue 3 (BB3) onto Cladium mariscus saw-sedge was studied in comparison with sawdust obtained from various species of wood in order to explore their potential application as low-cost sorbents for basic dye removal from wastewaters. The effect of phase contact time (1–240 min), initial dye concentration (50–200 mg/L), and the auxiliaries presence (10–60 g/L NaCl and 0.1–0.75 g/L anionic surfactant) on BB3 uptake was investigated. The adsorption kinetic data followed the pseudo-second order equation rather than pseudo-first order one. The equilibrium adsorption data were analyzed using the Langmuir, Freundlich, and Tempkin isotherm models. The monolayer sorption capacities decreased from 44.29 to 42.07 mg/g for Cladium mariscus saw-sedge and from 28.69 to 27.5 mg/g for sawdust with temperature increasing from 20 to 50 °C. The thermodynamic parameters such as the change in free energy (∆G°), enthalpy (∆H°), and entropy (∆S°) were calculated, too.

Application of Activated Carbon Adsorbents Prepared from Prickly Pear Fruit Seeds and a Conductive Polymer Matrix to Remove Congo Red from Aqueous Solutions

The present work was aimed to evaluate the adsorption properties of activated carbons based on prickly pear seeds (PPS) and conductive polymer matrix based on polyaniline (PANI) for the removal of anionic Congo red (CR) dye from aqueous solutions. The adsorbent was prepared by polymerization of aniline in the presence of activated PPS by phosphoric acid and sodium hydroxide. The samples were characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and the Brunauer–Emmett–Teller (BET) methods. The adsorption kinetics were studied using UV-visible (UV/Vis) spectroscopy. The characterization data suggest that the adsorption of the Congo red dye is enhanced because PANI chain molecules, which are especially accountable for removal through π–π interaction and H–bonding with the CR, are adsorbed/tethered onto the acid-activated PPS (PPSH), and thus surmount the mass transfer limitation by being best exposed to the CR-adsorbed molecule. The adsorption kinetics follows the pseudo-second order process. The correlation coefficients (R2) for Langmuir, Freundlich and Tempkin showed that the adsorption values obey Freundlich and Tempkin isotherm models. Moreover, the isotherm was most accurately described by the Freundlich model, and the maximum removal percentage was calculated to be 91.14% under optimized conditions of pH 6.6, 1 g/L of adsorbent dosage, and an initial CR dye concentration of 20 mg·L−1. Importantly, the hybrid adsorbent exhibited the highest adsorption capacity (80.15%) after five cycles of the adsorption–desorption process. Thermodynamic parameters, such as entropy changes, enthalpy changes and Gibbs free energy, were also evaluated. These results indicated that the PANI matrix can generally be better utilized for the removal of Congo red dye when appropriately dispersed on the surface of suitable support materials. These results provide a new direction to promote the separable adsorbents with increasing performance for adsorption of dye impurities from wastewater.

The utilization of Garcinia mangostana fibers for the removal of crystal violet dye

Despite of all health properties found in Garcinia mangostana, there are still only a few reports were made on natural fiber present on the pericarp. In this study, G. mangostana peels were collected and the fibers were extracted from the G. mangostana pericarp. The extracted fibers were characterized using FTIR and SEM. Later, the extracted fibers were subjected for batch adsorption studies for removal of crystal violet dye were the parameters like adsorbate- adsorbent concentration and pH were optimized. Adsorption isotherm like Langmuir, Freundlich and Tempkin isotherm were calculated.

A single rapid route synthesis of magnetite/chitosan nanocomposite: Competitive study

At last decides, the modification of synthesis protocol towards shorter reaction time, fewer steps, and lower resources cost was needed. The synthesis of magnetite (Fe3O4) polymer nanocomposite is heavily studied nowadays due to its promising applications. In this study, magnetite chitosan nanocomposite was synthesized through two competitive routes; a new single route synthesis based on co-precipitation at hydrothermal conditions, and the second route a conventional multi-synthetic route based on using the blending solution method after magnetite nanoparticles synthesis by the co-precipitation method of magnetite. The synthesized Fe3O4 and its nanocomposites are characterized by several techniques, including Fourier transition infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and vibration sample magnetometer (VSM). The results showed magnetite polymer nanocomposite synthesized via a single synthetic route had less particle size, more distribution in the chitosan matrix, and higher magnetization saturation than that synthesized via a multi-synthetic route. Adsorption of Rodamine 6G dye on magnetite chitosan nanocomposite was studied in different parameters. The adsorption results showed a rapid process following the Tempkin isotherm.

Efficacy of Algae powder (BAST) on uprooting of methylene blue dye (MBD): Optimization

In the present study experimental data was obtained for the removal of Methylene Blue Dye (MBD) by Brown Algae Sargassum tenerrimum (BAST) powder as a biosorbent in batch operation. The equilibrium Agitation time for methylene blue dye (MBD) was obtained at 120 min with percentage removal as 95.74percentage, Optimum dosage observed was 0.1 gm at pH = 6 for the particle size 90 µm. For the decolourisation of methylene blue dye (MBD) both Langmuir and Freundlich isotherm model was well fitted with the R2 values are 0.97 and 0.96 respectively and followed by Tempkin isotherm with R2 is 0.98. The kinetic studies show that the biosorption of methylene blue dye (MBD) is better described by Pseudo-second order kinetics. The Response Surface Methodology (RSM) optimal set of conditions for maximum biosorption of methylene blue dye (MBD) are time = 119.52 min, pH = 5.83, and Biosorbent Dosage = 1.2 g/L. The percentage biosorption of methylene blue is 95.8percentage. The critical values reported by optimization through RSM are very similar to the batch optimum studies values showing that BAST is having better efficiency fir the removal of MBD from aqueous solutions.

Kinetic and Thermodynamic Studies of Ion Exchange Process in Removal of Ca2+ and Mg2+ from Cooling Tower Water using Amberlite IR 120 and Amberjet 1200

In this study, the thermodynamics and kinetics parameters of the ion exchange process in removing Ca2+ and Mg2+ from cooling tower water using Amberlite IR1200 and Amberjet were investigated. Thermodynamics and kinetics were studied by varying the amount of contact time (min), adsorbent (mL), temperature (K), concentration (mg/L) and pH of the solutions. The effectiveness of pecentage removal was found to rely on pH, as there was a significant increase of removal percentage Ca2+ and Mg2+ from pH of 3 to 6. The contact time was reached after 60 min on both resins. The correlation coefficients (R2) of Langmuir, Freundlich and Tempkin isotherms ranged from 0.92 to 1, suggesting that the experimental data best described the models. However, correlation coefficients (R2) for the D-R model range between 0.5 to 0.8, which means that experimental data does not fit the model well. Thermodynamic functions such as entropy (ΔSº), enthalpy (ΔHº) and change of free energy (ΔGº) were obtained from the gradient and intercepts of straight-line graphs. The positive values of ΔGº indicated that the adsorption is not spontaneous. Positive values of ΔHº were found, meaning the endothermic type of adsorption, which indicates the chances of physical adsorption. The correlation coefficient (R2) values of pseudo-first-order, pseudo-second-order and intraparticle models ranged from 0.89 to 1 on both metals. This observation indicates that pseudo-first-order, pseudo-second-order and intraparticle diffusion models best describe the experimental data in removing Ca2+ and Mg2+ from cooling tower water.

Kinetics, Isotherms and Thermodynamic Studies on Removal of Divalent Copper using Mallet Flower Leaf Powder as Bio-Adsorbent

The effectiveness and efficacy of Mallet Flower Leaf Powder (MFLP) as a bio-sorbent for the removal of heavy metal copper ions from the aqueous solutions have been studied. Experiments were conducted varying the pH, agitation time, temperature, biosorbent size and dosage as parameters. Speed of the mixing is kept at 200 rpm. The analysis of copper was done by using Atomic Absorption Spectrophotometer (AAS). The adsorption of copper was found to be dependent on pH and a maximum removal of 98.78 % was obtained at an optimum pH of 6.0. The optimum biosorbent dosage was 1 g for an agitation time of 40 min. The biosorption data obtained were validated for the best isotherm. The data collected were verified with the available adsorption isotherms. Experimental data obtained was well represented by Langmuir (RL = 0.161, qm = 5.96 mg/g, R2 = 0.9142), Freundlich (n = 0.64, Kf = 0.79L/g, R2 = 0.9995) and Tempkin (R2 = 0.9083, bT = 267.63) isotherms, indicating favorable biosorption. The experimental data obtained were tested for the best fit and the Freundlich Model has yielded the best correlation with the highest regression coefficient, R2 = 0.9844. Kinetic data has also been presented using thermodynamic analysis and the pseudo second order model was found to be the best fit with a correlation coefficient of 0.999. For the removal of copper from the solution, bioadsorbent showed a maximum adsorption capacity of 5.96 mg/g.&#x0D; HIGHLIGHTS&#x0D; &#x0D; Removal of divalent copper from the aqueous solution using Mallet Flower Leaf powder&#x0D; Atomic Absorption Spectroscopy, Scanning Electron Microscopy and Fourier transform infrared analysis were used to characterize the Mallet Flower Leaf Powder&#x0D; Kinetic data has been presented using thermodynamic analysis and the pseudo second order model was found to be the best fit with a correlation coefficient of 0.999&#x0D; The maximum adsorption capacity of MFLP for copper was found to be 5.96 mg/gm&#x0D; &#x0D; GRAPHICAL ABSTRACT

A STUDY ON THE ADSORPTION OF Ni(II) IONS FROM WASTEWATER USING ACID ACTIVATED ANISOMELES MALABARICA LEAVES

In the present investigation, the efficiency of activated carbon prepared from Anisomeles malabarica leaves (AMC) as an adsorbent for the removal of Ni (II) ion was investigated. Anisomeles malabarica leaves were treated with sulphuric acid before adsorption. The influence of various operating conditions such as adsorbent dosage, initial concentration of adsorbate, contact time, pH and temperature were explored in a Batch adsorption technique. The Langmuir, Freundlich and Tempkin isotherm models were used to compute the experimental outcomes. Freundlich Isotherm model were fitted well than that of other two isotherm models. The maximum adsorption capacity was obtained as qm =361.73 mg/g with the optimum conditions of adsorbent dosage 25mg, temperature 30˚C, initial adsorbate concentration 30mg/L, contact time 30min and pH 6.5.