scholarly journals A prudent approach for the removal of copper (II) and cadmium (II) ions from aqueous solutions using indigenous Mactra aequisulcata shells

2021 ◽  
pp. 28-28
Author(s):  
Syed Rehan Ullah ◽  
Erum Zahir ◽  
Muhammad Asghar
Keyword(s):  
Point Of Zero Charge ◽  
Batch Experiments ◽  
First Order ◽  
Bet Isotherm ◽  
Equilibrium Data ◽  
Langmuir Isotherm Model ◽  
Pseudo First Order ◽  
Thermodynamic And Kinetic Parameters ◽  
Best Fit

In this study, the raw seashells of Mactra aequisulcata, of class Bivalvia and phylum Mollusca were employed as an adsorbent to remove copper (II) and cadmium (II) metal ions from aqueous solution. The characterization of shells was performed using FTIR, EDX and SEM, BET isotherm and point of zero charge (pHpzc). Batch experiments were performed to assess various factors on the biosorption efficiency. Maximum adsorption of both metals ions conveniently found at 0.4 g L-1 adsorbent dose, pH 5 and at 303 K. Maximum biosorption capacities for Cu2+ and Cd2+ were 59.57 and 38.12 mg g-1, respectively. The Langmuir isotherm model was found to be the best fit for the acquired equilibrium data. Thermodynamic and kinetic parameters presented that the process was feasible, exothermic and followed pseudo-first order.

scholarly journals Adsorptive Removal of As(III) from Aqueous Solution

2015 ◽  
Vol 19 (1) ◽  
pp. 150-154 ◽  
Author(s):  
Pushpa Bhattarai ◽  
Khagendra Prasad Bohra ◽  
Megh Raj Pokhrel
Keyword(s):  
Maximum Adsorption Capacity ◽  
Dalbergia Sissoo ◽  
Batch Studies ◽  
Adsorptive Removal ◽  
First Order ◽  
Chemically Modified ◽  
Ferric Salt ◽  
Langmuir Isotherm Model ◽  
Pseudo First Order ◽  
Best Fit

The iron-modified Dalbergia sissoo sawdust was synthesized by loading iron (III) onto phosphorylated Dalbergia sissoo sawdust via soaking in a ferric salt solution. Batch studies were performed at an initial concentration of 1 mg/l to evaluate the effect of parameters such as pH, equilibrium time, adsorbent dose and concentration of adsorbate. Kinetics and isotherm modeling studies demonstrated that the experimental data best fit a pseudo-first order and Langmuir isotherm model, respectively. The maximum adsorption capacity was found to be 1.33 mg/g for As(III) onto FePDSD suggesting the suitability of chemically modified Dalbergia sissoo sawdust for the adsorptive removal of As(III) from aqueous solution.Journal of Institute of Science and Technology, 2014, 19(1): 150-154

An automated approach to characterize, in simple kinetic terms, the generation and inactivation of thrombin and the interaction of fibrinogen with thrombin.

1988 ◽  
Vol 34 (10) ◽  
pp. 1971-1975 ◽  
Author(s):  
D R Hoak ◽  
S K Banerjee ◽  
G Kaldor
Keyword(s):  
Prothrombin Time ◽  
Rate Constant ◽  
Thrombin Generation ◽  
Order Rate Constant ◽  
Clinical Use ◽  
First Order ◽  
Pathological Conditions ◽  
Pseudo First Order ◽  
Instantaneous Concentration

Abstract Here, we used a fully automated, computer-directed centrifugal analyzer (which permitted simultaneous turbidimetry and calculation of results) and purified thrombin, fibrinogen, and various inhibitors to study clot formation. The Km and Vm for these reactions were useful in detecting and partly characterizing anticoagulants. We also explored the generation and inactivation of thrombin, using the two-stage prothrombin time and antithrombin activity tests. The amount of thrombin instantaneously generated and inactivated was monitored under artificially created pathological conditions. The pseudo-first-order rate constant for thrombin generation and inactivation and the instantaneous concentration of enzymatically active and inactive thrombin were used in the characterization of these conditions. We believe this approach is suitable for routine clinical use.

scholarly journals Comparative biosorption study of Hg (II) using raw and chemically activated almond shell

2017 ◽  
Vol 36 (1-2) ◽  
pp. 521-548 ◽  
Author(s):  
AA Taha ◽  
AHE Moustafa ◽  
HH Abdel-Rahman ◽  
MMA Abd El-Hameed
Keyword(s):  
Isotherm Models ◽  
Optimum Conditions ◽  
Almond Shell ◽  
Shell Surface ◽  
First Order ◽  
Biosorption Process ◽  
Equilibrium Data ◽  
Batch Biosorption ◽  
Best Fit ◽  
Langmuir And Freundlich Models

This work presents a comparison between the biosorption of Hg (II) by raw almond shell and activated almond shell. Almond shell based activated carbon has been obtained by physicochemical activation. Batch biosorption results confirmed that, activating condition has a strong influence on the final biosorption process. The biosorbent was characterized using scanning electron microscopy and Fourier transform infrared spectroscopy. To optimize the biosorption conditions pH, adsorbent dose, initial concentration, contact time, stirring speed, and temperature on Hg (II) removal were studied. The optimum conditions for maximum Hg (II) was achieved at 20 and 10 min for raw almond shell and activated almond shell, respectively. The equilibrium data were described well by Langmuir, Freundlich, Dubinin–Radushkevich isotherm models and appling a test of model fitness. Best fit of Langmuir and Freundlich models were found for experimental data, which reveal the homogenous surface of raw almond shell and the heterogeneity of activated almond shell surface. The kinetic data had been divided into either pseudo first order or second order on the basis of the best fit obtained from calculations, confirmed by a test of kinetic validity. An industrial application was examined to improve high biosorption capacity of raw and activated almond shells toward Hg (II).

scholarly journals Synthesis of citric acid-modified resins and their adsorption properties towards metal ions

2018 ◽  
Vol 5 (8) ◽  
pp. 171667 ◽  
Author(s):  
Xiong Liu ◽  
Longqi Xu ◽  
Yaqing Liu ◽  
Wenqi Zhou
Keyword(s):  
Citric Acid ◽  
Metal Ion ◽  
Adsorption Properties ◽  
Langmuir Model ◽  
Ion Concentration ◽  
First Order ◽  
Adsorption Capacities ◽  
Equilibrium Data ◽  
Pseudo First Order ◽  
Order Rate Equation

Types of resins anchored on citric acid were synthesized and identified. The citric acid-modified resins PS-CA, PS-O-CA and PS-N-CA were synthesized by anchoring citric acid on PS-Cl, PS-OH and PS-NH 2 , respectively. The PS-CA, PS-O-CA and PS-N-CA were used to adsorb Fe 3+ , Al 3+ , Cu 2+ , Pb 2+ , Cd 2+ and Hg 2+ . The influences of pH, adsorption time and metal ion concentration on the adsorption capacities of the resins were investigated. After optimization, PS-CA was a good adsorbent to Fe 3+ , Cu 2+ , Pb 2+ and Cd 2+ with q m values of 143.9 mg g −1 , 77.4 mg g −1 , 18.9 mg g −1 and 119.9 mg g −1 , respectively. PS-N-CA was a good adsorbent to Al 3+ and Hg 2+ with q m values of 176.6 mg g −1 and 114.9 mg g −1 , respectively. The adsorption kinetics and adsorption isotherm experiments indicated that the pseudo-first-order rate equation was more appropriate for characterizing the kinetic data and the Langmuir model was more suitable for fitting the equilibrium data. The reusability of the citric acid-modified resins was also evaluated and these resins exhibited considerable reusability.

scholarly journals Sulfuric Activated Carbon of Black Cumin (Nigella sativa L.) Seeds for the Removal of Cadmium(II) and Methylene Blue Dye

2020 ◽  
Vol 32 (6) ◽  
pp. 1361-1369
Author(s):  
Patience Mapule Thabede ◽  
Ntaote David Shooto ◽  
Thokozani Xaba ◽  
Eliazer Bobby Naidoo
Keyword(s):  
Methylene Blue ◽  
Activated Carbon ◽  
Nigella Sativa ◽  
Blue Dye ◽  
Methylene Blue Dye ◽  
Black Cumin ◽  
First Order ◽  
Adsorption Processes ◽  
Equilibrium Data ◽  
Pseudo First Order

Carbon from black cumin seeds was modified with 10 and 20% sulfuric acid to obtain the activated adsorbents. Pristine carbon from black cumin seeds, 10 and 20% H2SO4 activated carbon from black cumin seeds were labelled CBC, ACBC-10 and ACBC-20, respectively. The adsorbents were characterized by SEM, XRD, FTIR, TGA and BET. The adsorbents maximum trend for Cd(II) was ACBC-10 > ACBC-20 > CBC. The maximum capacity trend for methylene blue dye was ACBC-20 > ACBC-10 > CBC. The kinetic model best fitted pseudo second order for Cd(II) which gave r2 values of 0.991-0.998. The methylene blue fitted pseudo first order model with r2 values ranging from 0.993-0.997. Pseudo first order suggested that the adsorption mechanism for methylene blue onto adsorbents involved van der Waal forces of attraction. The equilibrium data fitted Langmuir isotherm model for CBC, ACBC-10 and ACBC-20 with r2 of 0.994 to 0.998 for the removal of methylene blue whilst the removal of Cd(II) followed Freundlich with r2 ranging from 0.992 to 0.997. This suggested that the different adsorption processes were involved between the adsorbate and the adsorbents. Gibb′s free energy (ΔGº) for Cd(II) and methylene blue onto CBC, ACBC-10 and ACBC-20 suggested that the reaction was spontaneous. The adsorption of Cd(II) and methylene blue was endothermic, positive values (ΔHº). This suggested that the enthalpy (ΔHº) had a weak interactive force process whose low energy is associated with electrostatic attraction.

scholarly journals Removal of the pesticide methomyl contained in simulated effluent from equipment washing by adsorption in residual orange bagasse

2020 ◽  
Vol 9 (11) ◽  
pp. e3569118528
Author(s):  
Thiago Ruiz Zimmer ◽  
Jailton Marques Silva ◽  
Diego Henrique de Aquino Rocha ◽  
Helder Lopes Teles ◽  
Domingos Sávio Barbosa ◽  
...  
Keyword(s):  
Experimental Data ◽  
Adsorption Capacity ◽  
Simulated Effluent ◽  
Carboxylic Groups ◽  
Effects Of Ph ◽  
Langmuir Isotherm Model ◽  
Pseudo Second Order ◽  
Solid Liquid ◽  
Best Fit

This work consists of the study of methomyl removal, an extremely toxic carbamate pesticide, contained in aqueous solutions synthesized, by adsorption in residual orange bagasse from industrial juices processing. The adsorption kinetics was studied by obtaining the best fit for the model of pseudo-second order (R2= 0.949). The Langmuir isotherm model adjusted better to the experimental data confirming the adsorption in monolayers, without interaction among the adsorbate molecules. The scanning electron microscopy (SEM) revealed that particulate adsorbents have rather irregular surface, but with rigid structure and virtually no internal pores. The characterization of the functional groups by infrared spectroscopy (FTIR) revealed the presence of hydroxyl, Carbonyl and carboxylic groups on the adsorbents particles surface. Central composite rotational design 2x2 (DCCR 2x2) was used for the statistical study of the effects of pH and solid/liquid ratio (R) on the methomyl adsorption capacity in orange bagasse particles. The obtained mathematical model adjusted well to the experimental data (R2= 95%). In the studied intervals the highest values of adsorption capacity (q) were 3.73 and 3.43 (mg.g-1), obtained under the conditions of pH 6.0 with R 0.017 g.mL-1 and pH 4.5 with R 0.015 g.mL-1, respectively. Thus, it was possible to conclude that there was a greater adsorption in assays containing greater adsorbent mass in pH slightly acid.

scholarly journals The Application of Monkey Cola Pericarp (Cola lepidota) in the Removal of Toluene from Aqueous Medium

2020 ◽  
pp. 53-67
Author(s):  
C. Obi ◽  
N. C. Ngobiri ◽  
L. C. Agbaka ◽  
M. U. Ibezim-Ezeani
Keyword(s):  
Aqueous Medium ◽  
Contact Time ◽  
Second Order ◽  
Phytochemical Screening ◽  
Order Model ◽  
Initial Concentration ◽  
First Order ◽  
Equilibrium Data ◽  
Pseudo Second Order ◽  
Pseudo First Order

The study focused on the investigation of the effectiveness of the pericarp of monkey kola (Cola lepidota) biomass (CLPB) in the removal of toluene from aqueous system. X-Ray Diffraction (XRD), Fourier Transform Infrared (FTIR), Scanning Electron Microscopy (SEM) and phytochemical screening methods were used for characterizing the biosorbent. The effects of contact time, pH, and concentration on biosorption process were studied. The phytochemical screening showed the presence of alkaloids, flavonoids, tannins, carbohydrate, saponins and steroids. Carboxylic, alkene and alcohol groups were found to be the principal functional groups. The highest percentage removal was 99.63% at toluene initial concentration of 40 mg/L and 98.30% at pH 8. The contact time 30 minutes gave better removal efficiency of 99.89%. Among the biosorption isotherm models tested (Langmuir, Freundlich, Dubinin Radushkevich and Temkin, respectively), the Langmuir model equation gave a better fit of the equilibrium data with a correlation coefficient (R2) of 0.99. The equilibrium data was tested with pseudo-first order and pseudo-second order models and pseudo-second order model (R² = 0.99) fitted more than the pseudo-first order model (R² = 0.85). This study has revealed that Cola lepidota is a potential biosorbent for the removal of toluene from aqueous medium under the operating conditions of contact time of 30 minutes, pH of 8 and initial concentration of 40 mg/g.

scholarly journals Organobentonite: Characterization and adsorptive properties towards phenol and its derivatives

2016 ◽  
Vol 48 (2) ◽  
pp. 167-176
Author(s):  
Sanja Marinovic ◽  
Marija Ajdukovic ◽  
Natasa Jovic-Jovicic ◽  
Predrag Bankovic ◽  
Zorica Mojovic ◽  
...  
Keyword(s):  
Point Of Zero Charge ◽  
Hexadecyltrimethylammonium Bromide ◽  
Order Kinetic ◽  
X Ray Diffraction ◽  
Phenol Derivatives ◽  
Order Kinetic Model ◽  
Langmuir Isotherm Model ◽  
Pseudo Second Order ◽  
Nitro Derivatives

Bentonite from Mecji Do locality in Serbia was modified with hexadecyltrimethylammonium bromide (HDTMA-Br), and the sample was denoted as HDTMA-MD. The characterization of the material included X-Ray diffraction, elemental analysis and point of zero charge determination. The adsorption of phenol and its nitro derivatives: 2-nitrophenol (2NP), 3-nitrophenol (3NP) and 4-nitrophenol (4NP) on HDTMA-MD was investigated. The adsorption capacity of HDTMA-MD toward phenol derivatives increased in the following order qe (phenol) < qe (3NP) < qe (2NP) < qe (4NP). The influence of adsorption time and initial concentration on the adsorption efficiency of HDTMA-MD was studied for 4NP. The data were best fitted with Langmuir isotherm model and the pseudo-second-order kinetic model.

scholarly journals Adsorbent Ability of Treated Peganum harmala-L Seeds for the Removal of Ni (II) from Aqueous Solutions: Kinetic, Equilibrium and Thermodynamic Studies

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Maryam Ghasemi ◽  
Nahid Ghasemi ◽  
Javad Azimi-Amin
Keyword(s):  
Maximum Adsorption Capacity ◽  
Batch Experiments ◽  
Peganum Harmala ◽  
Order Model ◽  
Adsorption Isotherms And Kinetics ◽  
Experimental Parameters ◽  
Equilibrium Data ◽  
Langmuir Isotherm Model ◽  
Pseudo Second Order ◽  
Kinetic Equilibrium

The main goal of this study was to evaluate the performance of new adsorbent, treated Peganum harmala-L seeds (TPHS), for the removal of Ni (II) from aqueous solution. Batch experiments were performed as a function of various experimental parameters. The adsorption studies included both equilibrium adsorption isotherms and kinetics. Equilibrium data fitted very well with the Langmuir isotherm model. Maximum adsorption capacity was determined 91.74 mg/g at pH 7. Kinetics studies showed better applicability for pseudo-second-order model for both adsorbents. The negative value of ΔG° confirmed the feasibility and spontaneity of TPHS for Ni (II) adsorption.

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