scholarly journals Biosurfactant rhamnolipid enhanced modification of corn stalk and its application for sorption of phenanthrene

2017 ◽  
Vol 76 (5) ◽  
pp. 1167-1176
Author(s):  
Le Tong ◽  
Weiting Liu ◽  
Weijia Lin ◽  
Chuling Guo ◽  
Jing Yang ◽  
...  
Keyword(s):  
Sorption Process ◽  
Corn Stalk ◽  
Acid Modification ◽  
Synthetic Chemicals ◽  
Low Concentrations ◽  
Exothermic Process ◽  
Modification Method ◽  
Polycyclic Aromatic ◽  
Pseudo Second Order ◽  
Kinetics Of

The application of modified agricultural wastes for removing polycyclic aromatic hydrocarbons (PAHs) from water is gaining a growing interest. However, most modified methods using synthetic chemicals may cause secondary pollution. To overcome this limitation, in this study, a rhamnolipid modified corn stalk (RL-CS) for the removal of phenanthrene (PHE) from aqueous solution was prepared using a rhamnolipid-enhanced acid modification method. RL-CS with higher surface area and lower polarity exhibited higher PHE removal efficiency than that of raw corn stalk (RCS). The adsorption kinetics of RL-CS fitted well with pseudo-second-order kinetics (R2 > 0.999). Sorption coefficients and carbon-normalized sorption coefficient of RL-CS were 4.68 and 2.86 times higher than that of RCS. Sorption process of RL-CS was nonlinear. Meanwhile, the sorption was an exothermic process and could occur spontaneously. The present study demonstrated that biosurfactant-modified biosorbent RL-CS may be of great potential for the removal of low concentrations of PAHs from the contaminated waters.

scholarly journals Biosorption and Diffusion Modeling of Pb(II) by Malt Bagasse

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Klaiani B. Fontana ◽  
Giane Gonçalves Lenzi ◽  
Erica R. L. R. Watanabe ◽  
Ervin Kaminski Lenzi ◽  
Juliana A. M. T. Pietrobelli ◽  
...  
Keyword(s):  
Sorption Process ◽  
Isotherm Models ◽  
Diffusion Modeling ◽  
Biosorption Capacity ◽  
Kinetic And Thermodynamic Parameters ◽  
Pseudo Second Order ◽  
Ph Optimization ◽  
Kinetics Of ◽  
And Diffusion

The removal of Pb(II) from water by biosorption processes onto malt bagasse was investigated and the kinetic and thermodynamic parameters were obtained; additionally a diffusion modeling was proposed. The characterization of malt bagasse was performed by FTIR and SEM/EDS. The experiments were conducted in batch system and an experimental design based response surface methodology was applied for agitation speed and pH optimization. The kinetics of biosorption followed pseudo-second-order model and the temperature of the process affected the biosorption capacity. Isotherm models of Langmuir, Freundlich, and Elovich were applied and the Langmuir model showed better fit and the estimated biosorption capacity was 29.1 mg g−1. The negative values obtained for ΔG° and positive values of ΔH° confirm, respectively, the spontaneous and endothermic nature of the process. The diffusion modeling was performed based on experiments in the absence of agitation to investigate the influence of the biosorbent on the sorption process of Pb(II) ions.

scholarly journals Evaluating the impact of exposure to environmental contaminants on human health

1996 ◽  
Vol 42 (8) ◽  
pp. 1345-1349 ◽  
Author(s):  
J B Silkworth ◽  
J F Brown
Keyword(s):  
Chemical Substances ◽  
The Public ◽  
Aromatic Hydrocarbon Receptor ◽  
Naturally Occurring ◽  
Synthetic Chemicals ◽  
Low Concentrations ◽  
Polycyclic Aromatic ◽  
Coplanar Polychlorinated Biphenyls ◽  
Proportional Contribution ◽  
The Impact

Abstract Humans are exposed daily to low concentrations of many different chemical substances, natural and some man-made. Although many of these substances can be toxic at high levels, typical exposures are far below the effect levels. The responses produced by man-made aromatic hydrocarbon receptor agonists, such as dioxins, polychlorinated dibenzofurans, coplanar polychlorinated biphenyls, and polycyclic aromatic hydrocarbons, are also produced, often to greater extents [corrected], by naturally occurring constituents of fried meat, cabbage, broccoli, cauliflower, cocoa, and curry. Our society seems to be concerned about the health risks associated only with the synthetic chemicals, regardless of their proportional contribution to the total agonist activity, and regulates on the basis of such concerns. It would be more protective of the public health to determine acceptable concentrations for each type of response, regardless of the origin of the inducing agent, and issue advisories or regulations accordingly.

scholarly journals Uptake Capacity of Pb2+ by Sulphonated Biomass of Cicer arietinum: Batch Studies

2013 ◽  
Vol 2013 ◽  
pp. 1-5
Author(s):  
A. A. Kale
Keyword(s):  
Cicer Arietinum ◽  
Sorption Process ◽  
Order Model ◽  
Experimental Conditions ◽  
Batch Mode ◽  
Batch Studies ◽  
Intraparticle Diffusion Model ◽  
Pseudo Second Order ◽  
Modeling Data ◽  
Kinetics Of

Fundamental investigation on the removal of heavy metal Pb2+ from aqueous solutions by sulphonated biomass (S-III) of Cicer arietinum is conducted in batch mode. The effect of different parameters such as contact time, sorbent dose, pH and temperature has been studied. Adsorption kinetic modeling data were found. The kinetics of biosorption results shows that sorption process is well explained by pseudo-second-order model with determination coefficients 0.998 for S-III under all experimental conditions. The sorption mechanism was determined by Weber and Morris intraparticle diffusion model. Thermodynamic parameters, namely, KD and ΔG,have also been calculated to determine the spontaneity of the process.

scholarly journals Cadmium and Lead Adsorption Capacities of Nigerian Ultisol Soil of Tropics

2019 ◽  
Vol 35 (3) ◽  
pp. 1004-1012 ◽  
Author(s):  
Henry Olumayowa Oluwasola ◽  
Jonnie Niyi Asegbeloyin ◽  
Alfred Ezinna Ochonogor ◽  
Julius Udeh Ani ◽  
Collins Ugochukwu Ibeji ◽  
...  
Keyword(s):  
Contact Time ◽  
Adsorption Process ◽  
Sorption Process ◽  
Maximum Adsorption Capacity ◽  
Lead Adsorption ◽  
Adsorption Capacities ◽  
Batch Technique ◽  
Pseudo Second Order ◽  
Cadmium And Lead ◽  
Kinetics Of

The study investigates the sorption of cadmium (Cd) and lead (Pb) by Nsukka urban soils, a Nigeria soil classified as an ultisol soil of tropics. Laboratory batch technique was utilized to investigate the effect of pH, temperature, contact time, and concentration on the adsorption process. Results showed that adsorption efficiency of the soils for Cd2+ and Pb2+ increased with increase in pH, temperature, and contact time but decreased with increase in concentration. The data from adsorption study was fitted to the Langmuir, Freundlich and Temkin adsorption isotherms, and results revealed that Langmuir isotherm fitted most satisfactorily. On the basis of the obtained maximum adsorption capacity (qmax) from the Langmuir model, the affinity of Cd and Pb for the studied soil was Pb2+ > Cd2+. Pseudo-second order (r2 ≥ 0.995-0.999) best described the kinetics of the sorption process for the metal ions in the soil.

scholarly journals Adsorbing low concentrations of Cr(VI) onto CeO2@ZSM-5 and the adsorption kinetics, isotherms and thermodynamics

2018 ◽  
Vol 77 (9) ◽  
pp. 2327-2340 ◽  
Author(s):  
Jianrui Niu ◽  
Xiuxiu Jia ◽  
Yaqing Zhao ◽  
Yanfang Liu ◽  
Weizhang Zhong ◽  
...  
Keyword(s):  
Adsorption Kinetics ◽  
Photoelectron Spectroscopy ◽  
Bet Surface Area ◽  
Isotherm Models ◽  
X Ray ◽  
Low Concentrations ◽  
Freundlich Adsorption Isotherm ◽  
Pseudo Second Order ◽  
Isotherms And Thermodynamics ◽  
Kinetics Of

Abstract The CeO2@ZSM-5 was prepared by the dipping method. We used ZSM-5 and CeO2 as the carrier and load components, respectively. The aim was to reduce the low concentration of Cr(VI) in simulated wastewater (the concentration of Cr(VI) ranged from 0.2 to 1 mg/L). The characteristics of ZSM-5 and CeO2@ZSM-5 samples were determined by X-ray powder diffraction (XRD), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and Brunauer–Emmett–Teller (BET). Characterization results showed that the particle size, BET surface area and pore volume for CeO2@ZSM-5 was around 0.783 nm, 421.307 m2/g and 0.313 m3/g, respectively. In addition, the optimum conditions were obtained by the orthogonal test, and the details were as follows: optimal pH, adsorbent dose, initial concentration of Cr(VI) and equilibrium time were 3, 5 g/L, 0.6 mg/L and 70 min respectively. The removal of Cr(VI) was 99.56% in these conditions. The pseudo-second-order model best described the adsorption kinetics of Cr(VI) onto CeO2@ZSM-5. Isotherm data were treated according to Langmuir, Freundlich and Temkin isotherm models. The results showed that the Freundlich adsorption isotherm model fitted best in the temperature range studied. Adsorption capacity increased with temperature, showing the endothermic nature of Cr(VI) adsorption. The desorption results showed the best recovery of Cr(VI) using 0.1 M HCl.

scholarly journals Equilibrium and Kinetic Study of Ammonium Sorption by Raphia farinifera

2019 ◽  
Vol 230 (10) ◽  
Author(s):  
Paweł Staroń ◽  
Paulina Sorys ◽  
Jarosław Chwastowski
Keyword(s):  
Chemical Nature ◽  
Sorption Process ◽  
Sorption Kinetics ◽  
Second Order ◽  
Isotherm Models ◽  
Mechanism Analysis ◽  
Order Model ◽  
Sorption Model ◽  
Pseudo Second Order ◽  
Kinetics Of

Abstract The study investigated the sorption capacity of biosorbent-raphia sp. against ammonia. Raphia fibers were used without and with the modification of its surface with NaCl, NaNO3, and K2SO4. The data was analyzed in the state of equilibrium using four isotherm models such as Langmuir, Freudlich, Temkin, and Dubinin-Radushkevich. The equilibrium of ammonia sorption for all studied systems was best described by the Freudlich isotherm model. On its basis, it can be assumed that the studied process is of chemical nature, which results from the value of the coefficient 1/n < 1. In order to confirm the sorption mechanism, analysis of the kinetics of the ammonia sorption process on raphia fibers was performed. Four kinetic models of sorption were calculated: pseudo-first-order model, pseudo-second-order model, Elovich model, and Webber-Morris intermolecular diffusion model. The sorption kinetics of the modeled ammonia waste were carried out using unmodified palm fibers and all kinds of surface modification. This process was best described by the pseudo-second-order sorption model, which can be considered as a confirmation of the chemical nature of ammonia sorption on raphia sp. fibers.

scholarly journals Application of Kinetic Models to the Sorption of Copper(II) on to Peat

2002 ◽  
Vol 20 (8) ◽  
pp. 797-815 ◽  
Author(s):  
Y.S. Ho ◽  
G. McKay
Keyword(s):  
Sorption Capacity ◽  
Fractional Power ◽  
Sorption Process ◽  
Order Equation ◽  
Second Order ◽  
Process Models ◽  
Elovich Equation ◽  
Pseudo Second Order ◽  
High Degree ◽  
Kinetics Of

A comparison of the kinetics of the sorption of copper(II) on to peat from aqueous solution at various initial copper(II) concentrations and peat doses was made. The Elovich model and the pseudo-second order model both provided a high degree of correlation with the experimental data for most of the sorption process. There was a small discrepancy at the initial stages of sorption which suggested that film diffusion or wetting of the peat may be involved in the early part of the sorption process. Models evaluated included the fractional power equation, the Elovich equation, the pseudo-first order equation and the pseudo-second order equation. The kinetics of sorption were followed based on the sorption capacity of copper(II) on peat at various time intervals. Results show that chemical sorption processes may be rate-limiting in the sorption of copper(II) on to peat during agitated batch contact time experiments. The rate constant, the equilibrium sorption capacity and the initial sorption rate were calculated. From these parameters, an empirical model for predicting the concentrations of metal ions sorbed was derived.

Adsorption Kinetics and Thermodynamics of Methyl Orange on Ethylenediamine-Modified Chitosan Magnetic Nano-Adsorbent

2012 ◽  
Vol 581-582 ◽  
pp. 273-276 ◽  
Author(s):  
Yu Hong Chen ◽  
Si Qian Hu
Keyword(s):  
Activation Energy ◽  
Methyl Orange ◽  
Adsorption Kinetics ◽  
Freundlich Isotherm ◽  
Sorption Process ◽  
Kinetics And Thermodynamics ◽  
Modified Chitosan ◽  
Pseudo Second Order ◽  
Kinetics Of ◽  
Nano Adsorbent

Ethylenediamine-modified chitosan magnetic nano-adsorbent (EMCN) was prepared and used for the sorption of methyl orange(MO). The kinetics of the sorption fitted well with the pseudo-second-order kinetics model. The activation energy of sorption (Ea) was determined to be 16.47 kJ.mol-1. Adsorption isotherms showed that the sorption process was consistent with both Langmuir and Freundlich isotherm, and the thermodynamic parameters were calculated and indicated that the sorption process was spontaneous and exothermic. The saturated sorption capacity is 247.66, 227.58, 214.19 mg.g-1 at 5°C, 25°C, 45°C(pH=5.6),respectively.

scholarly journals Equilibrium and Kinetics of U(VI)aq Adsorption on in situ Generated Fe2O3. nH2O

2019 ◽  
Vol 70 (10) ◽  
pp. 3482-3485
Author(s):  
Ioana Carmen Popescu (Hostuc) ◽  
Ligia Stoica ◽  
Carolina Constantin ◽  
Ana Maria Stanescu
Keyword(s):  
Kinetic Modelling ◽  
Sorption Process ◽  
Second Order ◽  
Chemical Component ◽  
Isotherm Models ◽  
Sorption Equilibrium ◽  
Equilibrium And Kinetics ◽  
Pseudo Second Order ◽  
Kinetics Of

The paper aims to present research results obtained at the study of equilibrium and kinetics of U(VI)aq sorption on in situ generated Fe2O3 x nH2O from model solutions. The studied systems represent U(VI) solutions with CU(VI) = 5-30 mg�L-1 for which maximum U(VI) removal efficiencies (%RU(VI) = 95.98) on in situ generated Fe2O3��nH2O were obtained in the following working conditions: pH = 8.75, tcontact = 30 min, [U(VI)] : [Fe(III)] =1:75 and stirring rate 250 RPM. The Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherm models were used to study U(VI) sorption equilibrium. Langmuir isotherm with the correlation coefficient R2 (0.9808) suggests that it involves physical interactions. Freundlich (R2 = 0.8349) and Temkin (R2 = 0.8715) models describe well the sorption process suggesting that there also exists a chemical component, complexing and/or co-precipitation. The kinetic modelling according to the pseudo-first and pseudo-second order models, respectively has demonstrated that the U(VI) sorption equilibrium follows the pseudo-second order equation suggesting a chemical component of the process.

Isothermal, Kinetic, and Thermodynamic Studies of Graphene Oxide Adsorption on Silk

2021 ◽  
Vol 8 (5) ◽  
pp. 18-29
Author(s):  
Arobindo Chatterjee ◽  
Vinit Kumar Jain
Keyword(s):  
Graphene Oxide ◽  
Freundlich Isotherm ◽  
Sorption Process ◽  
Order Kinetic ◽  
Solution Ph ◽  
Thermodynamic Studies ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Isothermal Kinetic ◽  
Kinetics Of

The properties of graphene enriched silk depend on the amount of graphene oxide (GO) adsorption on silk. GO dipping parameters include the GO solution pH, initial GO concentration, dipping time and temperature, and the type of substrate. The effects of GO dipping parameters on the sorption process are studied to achieve the maximum GO adsorption on the silk surface for the preparation of an economical graphene/silk-based textile product. In addition, equilibrium isotherms, kinetics, and thermodynamics of GO adsorption on the silk surface in a batch sorption process are examined to understand the adsorption mechanism. The Freundlich isotherm best describes the adsorption of GO onto the silk. A pseudo-second order kinetic model best describes the kinetics of GO adsorption. Thermodynamic studies reveal that GO adsorption is spontaneous and exothermic.

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