Pseudo-first Order Kinetic Equation Research Articles

Application of Recycled Rubber from Scrap Tyres in the Adsorption of Toluene from Aqueous Solution

The adsorption of toluene from aqueous solution using waste tyre rubber granules (WTRG) was investigated in a batch system. The effect of various factors such as contact time, amount of adsorbent, size of adsorbent particles, and temperature of solution on the adsorption capacity of WTRG was determined. The equilibrium contact time was obtained to be 30 minutes indicating fast adsorption. The adsorption capacity of WTRG increased with decrease in particle size. Increasing the temperature of the aqueous solution resulted in a decrease in the adsorption capacity of WTRG while an increase in adsorbent dosage resulted in an increase in the adsorption capacity of WTRG. Kinetic and isotherm studies indicate that the adsorption of toluene was best described by the Lagergren pseudo-first order kinetic equation and Langmuir isotherm equation respectively. Results obtained indicate that recycled rubber from scrap tyres can be widely used as an adsorbent for the removal of toluene from aqueous solution.

Ultrasound assisted the preparation of 1-butoxy-4-nitrobenzene under a new multi-site phase-transfer catalyst – Kinetic study

In the present research work deals with the preparation of 1-butoxy-4-nitrobenzene was successfully carried out by 4-nitrophenol with n-butyl bromide using aqueous potassium carbonate and catalyzed by a new multi-site phase-transfer catalyst (MPTC) viz., N1,N4-diethyl-N1,N1,N4,N4-tetraisopropylbutane-1,4-diammonium dibromide, under ultrasonic (40kHz, 300W) assisted organic solvent condition. The pseudo first-order kinetic equation was applied to describe the overall reaction. Under ultrasound irradiation (40kHz, 300W) in a batch reactor, it shows that the overall reaction greatly enhanced with ultrasound irradiation than without ultrasound. The present study provides a method to synthesize nitro aromatic ethers by ultrasound assisted liquid–liquid multi-site phase-transfer catalysis condition.

Modeling of experimental data for the adsorption of methyl orange from aqueous solution using a low cost activated carbon prepared from Prosopis juliflora

This paper presents the feasibility for the removal of methyl orange (MO) dye from aqueous solution using an activated carbon prepared from Prosopis juliflora bark. Batch adsorption experiments were carried out as a function of pH, contact time, adsorbate concentration, adsorbent dosage and temperature. The commonly applicable isotherms namely Freundlich and Langmuir equations are used for the prediction of isotherm parameters. A comparison of linear least-square method and a trial-and-error non-linear method are examined in Freundlich and Langmuir (Four forms) isotherms. The nature of adsorption isotherm feasibility was evaluated with dimensionless separation factors (RL). The dynamics of adsorption process was analyzed with Lagergren’s Pseudo-first order and Pseudo-second order kinetic equations. Thermodynamic parameters like the change in enthalpy (ΔHo), change in entropy (ΔSo) and change in Gibbs free energy (ΔGo) were evaluated and ΔGo shows a negative value whereas ΔHo shows the positive value indicating that the adsorption process was spontaneous and endothermic in nature. The functional group characterization of the adsorbent was done using Fourier transform infrared spectroscopy (FTIR). The thermal stability of activated carbon was analyzed using Thermo gravimetric analysis (TGA) and Differential thermal analysis (DTA).

Photocatalytic degradation of methylene blue and inactivation of Gram-negative bacteria by TiO2 nanoparticles in aqueous suspension

The photocatalytic degradation of methylene blue (MB) and inactivation of Gram-negative bacteria Escherichia coli (generic) and Pseudomonas aeruginosa by TiO2 nanoparticles in aqueous suspension were studied. TiO2 resulted in significant reduction in MB absorption and a shift of MB absorption peak from 664 nm to 658 nm after a short time of irradiation. The maximum degradation of MB was observed when the concentration of TiO2 in the aqueous suspension was 0.5 g L−1. TiO2 was also very effective with inhibiting growth of both Gram-negative bacteria E. coli and P. aeruginosa, although it took more than 60 min to observe the inactivation effects. The photocatalytic inactivation toward E. coli and P. aeruginosa by TiO2 showed a similar trend with much higher effectiveness toward E. coli under the same experimental conditions. The inactivation kinetic behaviors could be explained by the modified Langmuir–Hinshelwood model, and well fitted to a pseudo-first order kinetic equation. The reaction rate constant for E. coli and P. aeruginosa were 7.768 × 106 cfu mL−1 min−1 and 5.655 × 106 cfu mL−1 min−1, respectively. The adsorption equilibrium constant for E. coli was 1.053 × 10−8 mL cfu−1, while it was 1.438 × 10−8 mL cfu−1 for P. aeruginosa. These results further demonstrate that in an aqueous system, TiO2 nanoparticles can effectively both degrade organic compounds and inhibit Gram-negative bacteria under UVA light. Compared with the degradation activity of TiO2 toward organic compounds, its antimicrobial activity against Gram-negative bacteria would be delayed by 60 min. The antimicrobial activity of TiO2 against Gram-negative bacteria could vary with bacterial species.

Preparation of 1,3-bis(allyloxy)benzene under a new multi-site phase-transfer catalyst combined with ultrasonication – A kinetic study

In the present work, kinetics of synthesis of 1,3-bis(allyloxy)benzene was successfully carried out by O-allylation of resorcinol with allyl bromide using aqueous potassium hydroxide and catalyzed by a new multi-site phase-transfer catalyst viz., 1,3,5,7-tetrabenzylhexamethylenetetraammonium tetrachloride, MPTC under ultrasonic (40kHz, 300W) assisted organic solvent condition. The pseudo first-order kinetic equation was applied to describe the overall reaction. Under ultrasound irradiation (40kHz, 300W) in a batch reactor, it shows that the overall reaction rate can be greatly enhanced to seven fold faster with ultrasound irradiation than without ultrasound. The present study provides a method to synthesize ethers by ultrasound assisted liquid–liquid phase-transfer catalysis condition.

Removal of copper from acid wastewater of bioleaching by adsorption onto ramie residue and uptake by Trichoderma viride

A continuous batch bioleaching was built to realize the bioleaching of sewage sludge in large scale. In the treatment, heavy metal in acid wastewater of bioleaching was removed by adsorption onto ramie residue. Then, acid wastewater was reused in next bioleaching batch. In this way, most time and water of bioleaching was saved and leaching efficiency of copper, lead and chromium kept at a high level in continuous batch bioleaching. It was found that residual heavy metal in sewage sludge is highly related to that in acid wastewater after bioleaching. To get a high leaching efficiency, concentration of heavy metal in acid wastewater should be low. Adsorption of copper from acid wastewater onto ramie residue can be described by pseudo first-order kinetics equation and Freundlich isotherm model. Trichoderma viride has the potential to be used for the concentration and recovery of heavy metal adsorbed onto ramie residue.

Функционализация поверхности целлюлозы тиосемикарбазидными группами с целью создания сорбента для концентрирования и определения тяжелых металлов в водах

A novel cellulose adsorbent bearing chemically immobilized thiosemicarbaside is synthesized. The adsorbent is used for the preconcentration of cobalt (II), mercury (II), and cadmium (II) followed by their X-ray fluorescence quantification in the concentrate. After approximation of experimental data on sorption capacity dependency on equilibrium concentration of element in the solution in coordinates of the Langmuir equation, the linear functions with correlation coefficient ≥ 0.99 were obtained. These functions we used to calculate maximum adsorption capacity (A мах ) and adsorption equilibrium constant. Using pseudo-first order kinetic equations for the approximation of experimental data on time-dependencies of sorbents capacity for Сd 2+ , Co 2+ , Hg 2+ the sorption rate constants were calculated. The possibility of determination of adsorbed Сd 2+ , Co 2+ , Hg 2 , by X-ray fluorescence in the sorbent phase was estimated for concentration phase under static conditions and pH =9 in case of the presence of all metals. Keywords : cellulose adsorbent, thiosemicarbazide, preconcentration (Russian) DOI: http://dx.doi.org/10.15826/analitika.2013.17.4.004 Dzh.N. Konshina, Z.A. Temerdashev, V.V. Konshin, E.I. Byshkina Federal State Educational Institution of Higher Professional Education «Kuban State University» , Krasnodar, Russian Federation

Kinetics of the adsorption of hexavalent Chromium from aqueous solutions on low cost material

This study proposes a Jordanian Pottery (Pot-Jo) as a low cost adsorbent for the removal of chromium from aqueous solutions. The effect of contact time, initial concentration of Cr(VI), temperature and ionic strength on the adsorption of Cr(VI) onto Pot-Jo were studied and discussed. The equilibrium (qe) of adsorption of Cr(VI) onto pottery were found to be 20.287, 17.55, and 13.577 mg Cr(VI) per gram of pottery at temperatures 25, 35, and 45°C, respectively. Five kinetic models, the pseudo first-order equation, the pseudo second-order equation, the Elovich equation, the Ritchie’s equation, and the intraparticle diffusion model were tested with respect to their adequacy to describe the adsorption process. The mechanism of adsorption was investigated by using the intraparticle diffusion model. It was found that there was no significant effect of the ionic strength on the removal of Cr(VI) from its solutions. Kinetic parameters, rate constants, equilibrium adsorption capacities and correlation coefficients, for each kinetic equation were calculated and discussed. Activation energy values were found to be between 13.85 and 33.10 kJ mol-1. The Ritchie and pseudo-first order kinetic equation were found to correlate the experimental data well. The rate determining step is well described by intraparticle diffusion process. The kid values ranging from 1.326 to 0.963 mgg-1min-1/2. Key words: Chromium (VI), Sorption kinetics, Pseudo-second order, Lagergren, Tempkin.

Kinetics, mechanism, isotherm and thermodynamic analysis of adsorption of cadmium ions by surface-modified Strychnos potatorum seeds

The surface-modified Strychnos potatorum seeds (SMSP) were used as an effective low-cost adsorbent for the removal of cadmium ions from aqueous solution. SMSP was characterized by Fourier transform infrared spectroscopy and scanning electron microscopic analyses. The effect of operating variables such as solution pH, adsorbent dose, contact time, initial cadmium ions concentration and temperature on the removal of cadmium ions were studied in a batch mode adsorption operation. The optimum conditions for the adsorption of cadmium ions onto the SMSP were found to be: pH of 5.0, SMSP dose of 2 g/L, contact time of 30min, temperature of 30 °C for an initial cadmium ions concentration of 100 mg/L. Kinetic data were analyzed using the pseudo-first order and pseudo-second order kinetic equations, intraparticle diffusion model, Boyd kinetic model and shrinking core model. The characteristic parameters for each model have been estimated. Adsorption of cadmium ions onto the SMSP follows the pseudo-second order kinetic model. The rate-limiting steps in the adsorption process were found to be external and internal diffusion. Equilibrium data were well described by the Langmuir isotherm model than the Freundlich isotherm model, which yields a maximum monolayer adsorption capacity of 200 mg/g. Thermodynamic parameters such as standard free energy change, enthalpy change and entropy change were also estimated. The results show that the removal of cadmium ions by the SMSP was found to be spontaneous and exothermic.

A mechanistic approach to methylene blue sorption on two vegetable wastes: Cork bark and grape stalks

Two vegetable wastes, cork bark and grape stalks, were investigated for the removal of methylene blue from aqueous solution. The effects of contact time, dye concentration, pH, and temperature on sorption were studied relative to adsorption on a commercially-activated carbon. The highest adsorption yield was obtained within the pH range 5 to 10 for grape stalks and 7 to 10 for cork bark. The sorption kinetics of dye onto activated carbon and grape stalks was very fast. Kinetics data were fitted to the pseudo-first and second order kinetic equations, and the values of the pseudo-second-order initial rate constants were found to be 1.69 mg g-1 min-1 for activated carbon, 2.24 mg g-1 min-1 for grape stalks, and 0.90 mg g-1 min-1 for cork bark. Langmuir maximum sorption capacities for activated carbon, grape stalks, and cork bark for methylene blue estimated by the Orthogonal Distance Regression method (ODR) were 157.5 mg g-1, 105.6 mg g-1, and 30.52 mg g-1, respectively. FTIR spectra indicated that carboxylic groups and lignin play a significant role in the sorption of methylene blue. Electrostatic forces, n-p interactions, cation-p, and p-p stacking interactions contribute to methylene blue sorption onto grape stalks and cork bark. Grape stalks can be considered an efficient biosorbent and as a viable alternative to activated carbon and ion-exchange resins for the removal of methylene blue.

Degradation Kinetics of Reactive Brilliant Red X-3B Dye by UV/Mn<sup>2+</sup>/H<sub>2</sub>O<sub>2</sub>/Micro-Aeration

Abstract. Degradation of reactive brilliant red X-3B (X-3B) by a UV/Mn2+/H2O2/micro- aeration method was investigated. The influencing factors of degradation of X-3B including UV irradiation, aeration, pH value, H2O2 concentration and X-3B concentration were examined. The results show that X-3B was effectively degraded by the UV/Mn2+/H2O2/micro-aeration method. The degradation rate of X-3B was obtained from weighted linear least squares analysis of the experimental data, and accorded with the pseudo-first order kinetics equation.

Preparation and Characterization of Nd-Doped Ti/SnO<sub>2</sub>-Sb<sub>2</sub>O<sub>5</sub> Electro-Catalytic Electrodes Used for Reactive Brilliant Red X-3B Wastewater Treatment

The best catalytic capacity of Nd-doped Ti/SnO2-Sb2O5 electrodes was obtained by sol-gel preparation. Nd-doped Ti/SnO2-Sb2O5 coating was characterized using technique such as scanning electron microscopy (SEM), and X-ray diffraction (XRD). Nd-doped electrode fragments looks smaller, more compact and more uniform than undoped electrode through SEM. The crystal cell’s average diameter of Nd-doped electrodes was 3.48nm through XRD. BOD5/COD of Reactive Brilliant Red X-3B increased 200% under optimum conditions after 1h electrolysis. Instantaneous current efficiency (ICE) was 51.15 % in first 40 min, 35.73 % in first 60 min. In the first 40 minutes of electrolysis process, COD of Reactive Brilliant Red X-3B changes conformed to the pseudo first-order kinetic equation. Electrical Properties Tests showed that the oxygen evolution potential values of Nd-doped electrodes were higher than the undoped electrodes in various media.

Equilibrium, kinetic and thermodynamic studies on the biosorption of reactive acid dye on Enteromorpha flexuosa and Gracilaria corticata

Biosorption is an emerging, eco-friendly and economical method for treating the wastewater effluents. Compared to many other biological materials, algae biomass proved to be the better biosorbent due to the presence of cell wall polymers in them. Algal biomasses namely Enteromorpha flexuosa and Gracilaria corticata were dried, crushed and used as biosorbents. Ponceau S, a diazo dye was used as a model adsorbate for the biosorption studies. The biosorbents were characterized by Scanning Electron Microscopy, FT-IR and zero point charge. Batch studies were performed by varying pH, biosorbent dosage and initial dye concentrations. Adsorption isotherms, kinetic and thermodynamic analyses were carried out. The effect of electrolytes was also studied. Batch desorption studies were also carried out using various reagents. Isotherm data were tested with Langmuir and Freundlich isotherm models and the results suggested that the Freundlich isotherm fitted the data well. Kinetic studies were performed with varying initial dye concentrations and the data were incorporated with pseudo first-order and pseudo second-order kinetic equations and was found that the studied biosorption processes followed pseudo second-order kinetic equation. Thermodynamic parameters were evaluated at three different temperatures 293 K, 300 K and 313 K. About 95% of the dye could be desorbed from both the biosorbents. Both the algal biomasses had heterogeneous surfaces and followed pseudo second-order chemical kinetics. Thermodynamic parameters proved that the biosorption by both the biomasses were spontaneous, feasible and endothermic processes. Desorption studies proved the worth of the algal biomasses as biosorbents in industrial level.

Removal of Nitrophenols by Adsorption Using β-Cyclodextrin Modified Zeolites

Removal of nitrophenols (NPs) from aqueous solutions through the adsorption process by using cationic β-cyclodextrin (CCD) modified zeolite (CCDMZ) was investigated. The effects of particle size, contact time, solution pH values and sodium chloride content in the aqueous on adsorption capacity were evaluated through a series of batch experiments. The results showed that CCDMZ had a higher adsorption capacity for removing NPs at a size fraction of 0.45–0.9 mm while adsorption of NPs on CCDMZ reached equilibrium within 60 min. The adsorption process was apparently influenced by pH values and sodium chloride content in aqueous solution. To ascertain the mechanisms of sorption, the experimental data were modeled by using the pseudo-first and pseudo-second order kinetic equations, and the results indicated that the adsorption kinetics of NPs on CCDMZ well-matched with the pseudo-second order rate expression.

Adsorption of cadmium on carbonaceous adsorbents developed from used tire rubber

Carbonaceous adsorbents (CAs) are developed from used tire rubber (UTR) and tested as adsorbents of Cd 2+ in aqueous solution. In the preparation of the CAs, UTR was treated thermally at 400–900 °C for 2 h in N 2 and at 850 °C for 2 h in steam. Concentrated NaOH, HCl, H 2SO 4, HNO 3 and H 2O 2 solutions were also used. UTR and H900 (i.e. UTR pyrolyzed at 900 °C) were treated with O 3 at 25 °C for 1 h and with air at 250 °C for 1 and 24 h. CAs were characterized texturally by N 2 adsorption at −196 °C, mercury porosimetry, and density measurements. The surface groups were analyzed by FT-IR spectroscopy. Using the batch method, the adsorption process of Cd 2+ was studied mainly from the kinetic standpoint at various pH values of the adsorptive solution. Significant porosity developments are achieved only when UTR is heat-treated, in particular in steam. However, the variety and concentration of surface groups are low in CAs. This is so even for CAs prepared using oxidizing agents as strong as O 3 and H 2O 2, which has been associated with a lack of available or accessible surface active sites for oxidation in UTR and H900, respectively. Thermal and thermal-chemical treatments are usually more effective than chemical treatments to increase the adsorption of Cd 2+ in aqueous solution. The adsorption process of Cd 2+ is first fast and then much slower. Adsorption-time data fit better to a pseudo-second order kinetic equation than to a pseudo-first order kinetic equation. The extent to which the adsorption process occurs is strongly dependent on the pH of the Cd 2+ solution, being larger at pH 4.6 or 7.0 according to the adsorbent.

Adsorption of copper ion from its aqueous solution by a novel biosorbent Uncaria gambir: Equilibrium, kinetics, and thermodynamic studies

In this paper, gambir was chemically modified into insoluble adsorbent (GA). The GA was characterized by FTIR, pH zpc, SEM, and BET. The effects of pH, adsorbent dosage, initial concentration of Cu 2+ solution and contact time were studied. Batch experiments were performed with aqueous copper solutions of concentration 10 mg/L, at pH 5.0 and 0.30 g adsorbent. The experimental data was analyzed using pseudo-first order, pseudo-second order and Elovich kinetic models. The correlation coefficient calculated from pseudo-second order equation was higher than pseudo-first order and Elovich kinetic equations, indicating that equilibrium data fitted well with pseudo-second order model where adsorption process was chemisorptions. The adsorption equilibrium was well described by Langmuir isotherm model. The maximum adsorption capacity was found to be 9.950 mg/g at 333 K. The Gibbs free energy change, Δ G°, values were negative indicating that the process of Cu 2+ ions adsorbed onto GA was spontaneous. The positive values of Δ H° and Δ S° suggested that the process of adsorption was endothermic at high temperature.

Equilibrium and Kinetic Modelling of Astrazon Yellow Adsorption by Sawdust: Effect of Important Parameters

This paper aims to investigate the sorption of Astrazon yellow (A.Y.) onto sawdust (Aleppo pine tree), a forest waste as that acts as a low-cost adsorbent. In our experiments, the batch sorption is studied with respect to solute concentration, contact time, adsorbent dose, particle size and pH. The adsorption process attains equilibrium within 300 minutes. The extent of dye removal decreased with increasing particle size and increased with increasing contact time, adsorbent dose and pH. The equilibrium data were analysed by the Langmuir and Freundlich isotherms. The characteristic parameters for each isotherm were determined. By considering the experimental results and adsorption models applied in this study, it can be concluded that equilibrium data were represented well by the Langmuir isotherm equation. Maximum adsorption capacity calculated at 293K was 81.8 mg/g. Five kinetic models (pseudo-first order, pseudo-second order, fractional power, Elovich and intraparticle diffusion kinetic equations) were used to predict the adsorption rate constants. The kinetics of adsorption of the basic dye followed both Elovich and pseudo-second order kinetics, and intraparticle diffusion was not the sole rate-controlling step. The effective diffusion of Astrazon yellow in sawdust according to Boyd Model was 24.22 .10-12 m2/S. In order to reveal the adsorption characteristic of sawdust samples, SEM and FTIR spectra analyses were carried out. The results show that sawdust (Aleppo pine tree) can be an alternative low-cost adsorbent for removing cationic dyes from wastewater.

Preparation and application of glycidyl methacrylate and methacrylic acid monomer mixture-grafted poly(ethylene terephthalate) fibers for removal of methylene blue from aqueous solution

A novel fibrous adsorbent that grafts glycidyl methacrylate (GMA) and methacrylic acid (MAA) monomer mixture onto poly(ethylene terephthalate) (PET) fibers was used for removal of methylene blue (MB) in aqueous solutions by a batch equilibration technique. The operation parameters investigated included, pH of solution, removal time, graft yield, dye concentration, and reaction temperature. The adsorption rate of MB is much higher on the MAA/GMA-grafted PET fibers than on the ungrafted PET fibers. MB was removed 99% the initial dye concentration at 10 mg L−1 and 93% at 200 mg L−1 by monomers mixture-grafted PET fibers. Pseudofirst order and pseudosecond order kinetic equations were used to examine the experimental data of different graft yield. It was found that the pseudosecond order kinetic equation described the data of dye adsorption on fibrous adsorbent very well. The experimental isotherms data were analyzed using Langmuir and Freundlich isotherm models. The data was that Freundlich isotherm model fits the data very well for the dyes on the fibers adsorbent. The dye adsorbed was easily desorbed by treating with acetic acid/methanol mixture (50% V/V) at room temperature. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Using resin supported nano zero-valent iron particles for decoloration of Acid Blue 113 azo dye solution

In this study, a synthesized cation exchange resin supported nano zero-valent iron (NZVI) complex forming NZVI–resin was proposed for the decoloration of an azo dye Acid Blue 113 (AB 113), taking into account reaction time, initial dye concentration, NZVI dose and pH. From results, the successful decoloration of the AB 113 solution was observed using a NZVI–resin. Increasing the iron load to 50.8mgg−1, the removal efficiencies of the AB 113 concentration increased exponentially. With an initial dye concentration of 100mgl−1 and nano iron load of 50.8mgg−1, the best removal efficiencies were obtained at 100 and 12.6% for dye concentration and total organic carbon, respectively. Color removal efficiency was dependent on initial dye concentration and iron load. Moreover, the removal rates followed modified pseudo-first order kinetic equations with respect to dye concentration. Thus, the observed removal rate constants (k) were 0.137–0.756min−1 by NZVI loads of 4.9–50.8mgg−1. Consequently, the NZVI–resin performed effectively for the decoloration of AB 113 azo dye, offering great potential in the application of NZVI–resins in larger scale column tests and further field processes.

Adsorption of cationic polyacrylamide (C-PAM) on expanded perlite

The adsorption of cationic polyacrylamide (C-PAM) onto expanded perlite (EP) from aqueous solutions was investigated as a function of some parameters such as pH, ionic strength, and temperature. The adsorption of C-PAM was increased with increasing pH and temperature and with decreasing ionic strength. The Langmuir isotherm model fitted the isotherm data better than the Freundlich model. The electrophorotic mobility of EP dispersions was measured in aqueous solutions of NaCl and at different C-PAM concentrations and pH. The thermodynamic parameters Gibbs free energy, enthalpy, and entropy were evaluated. The dimensionless separation factor ( R L ) revealed that EP can be used for adsorption of C-PAM from aqueous solutions. The pseudo first-order kinetics equation best fitted the experimental data.