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

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.

2016 ◽  
Vol 14 (2) ◽  
pp. 549-558 ◽  
Author(s):  
Kadriye Bozgeyik ◽  
Turkan Kopac

Abstract In this study, adsorption properties of arc produced Multi Walled Carbon Nanotubes (MWNT) were investigated for Bovine Serum Albumin (BSA) in aqueous phase. Solution pH, adsorbent amount and temperature effects were examined on protein adsorption. The results show that, the temperature and the adsorbent amount both increase the BSA adsorption, whereas the solution pH has a decreasing effect. The equilibrium behavior of protein adsorption was examined by Langmuir and Freundlich isotherms. The monolayer adsorption capacities at 40 °C for solution pH 4 and 5 were determined as 139.5 and 127.2 mg g−1, respectively, which were much higher than the BSA adsorption capacities of various metal oxides investigated in our previous studies. The adsorption rate data were compared by the pseudo-first and the second-order kinetics equations. Evaluation of the experimental kinetics data have shown that the adsorption of BSA by MWNT followed the pseudo-first-order kinetics. The pseudo-first order adsorption rate constants at pH 4 and 5 decreased with an increase in temperature which results in a decrease in diffusion rate of BSA molecules across the external boundary layer, and favors the sorption process. The adsorption behavior of protein by carbon nanotubes was explained also using the zeta potential measurements. The adsorption capacity decreased with increasing pH due to the electrostatic repulsions. The thermodynamic parameters evaluated to predict the nature of adsorption confirmed the non-spontaneous and endothermic behaviour of the BSA/MWNT adsorption process. Adsorption standard enthalpy values were found as ∆H0=59.5 kJ mol−1 and ∆H0=14.3 kJ mol−1 for pH 4 and 5, respectively indicating that the protein molecules are adsorbed electrostatically on the carbon nanotubes.


2018 ◽  
Vol 2 (3) ◽  
pp. 35 ◽  
Author(s):  
Edidiong Asuquo ◽  
Alastair Martin ◽  
Petrus Nzerem

An agricultural residue, white yam (Dioscorea rotundata) tuber peel (YTBS), was used for the removal of Cd(II) ion from an aqueous solution using a batch method. The adsorbent was characterized using FTIR, TGA, SEM, EDX, N2 BET, XRD, and XRF. The optimization of sorption variables such as pH, contact time, adsorbent dose, and initial metal ion concentration at 25 °C were also carried out. The results indicated the dependence of sorption on the adsorbate pH and adsorbent dose, while the adsorption system reached equilibrium in 180 min. The sorption kinetics was fitted to three models (pseudo first order, pseudo second order, and Elovich) to validate the kinetics, and the pseudo first order was the best model for the description of Cd(II) uptake. Equilibrium isotherm modelling was also carried out using the Langmuir, Freundlich, and Temkin models, with the Langmuir isotherm giving the best fitting to the experimental results. The maximum loading capacity (qmax) of the adsorbent for Cd(II) obtained from the Langmuir isotherm model was 22.4 mg∙g−1 with an isotherm constant (KL) of 3.46 × 10−3 L·mg−1 and r2 value of 0.99. This result indicates that the YTBS residue was a good adsorbent for the removal of Cd(II) ion from aqueous system.


Author(s):  
Marek Lipovský ◽  
Maroš Sirotiak ◽  
Maroš Soldán

Abstract Removal of copper from aqueous solution on the natural and modified clinoptilolite was studied under static conditions. Batch adsorptions of copper were performed to investigate the effects of contact time and initial metal ion concentration. The Freundlich and Langmuir adsorption isotherms were used to analyse the experimental data. The kinetic analyses of the adsorption processes were performed using the pseudo-first-order and pseudo-second-order kinetic models.


2013 ◽  
Vol 11 (2) ◽  
pp. 160-170 ◽  
Author(s):  
Juan Moreno-Piraján ◽  
Liliana Giraldo

AbstractActivated carbon obtained from bamboo waste was synthesised and modified with iron (BAC-Fe) and used for the removal of arsenic from aqueous solutions. Two different adsorption models were used for analysing the data. The adsorption capacities were determined for BAC-arsenite, BAC-Fe-arsenite, BAC-arsenate and BAC-Fe-arsenate, with a qmax (µg g−1) of 14.89, 19.19, 22.32 and 27.32 respectively. Adsorption capacity varied as a function of pH and modifications to the sorbent. Adsorption isotherms from an aqueous solution of arsenite and arsenates on activated carbons were determined. These adsorption isotherms were consistent with the Langmuir and Freundlich adsorption models. Adsorption kinetics followed a pseudo-first order rate equation, as did the kinetics for BAC-Fe-arsenite and BAC-Fe-arsenate adsorption.


2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Seyed Naser Azizi ◽  
Abasalt Hosseinzadeh Colagar ◽  
Seyede Maryam Hafeziyan

Biosorption of Cd(II) ions from aqueous solutions by native and driedOscillatoriasp. Cyanobacterium biomass was investigated in the batch mode. TheOscillatoriasp. was prepared from Molecular and Cell Laboratory of University of Mazandaran and grown in BG-11 medium. A comparison of Cd(II) adsorption properties of dried with nativeOscillatoriasp. biomass was made, the dried one showed a higher biosorption capacity and faster kinetic. The influence of solution pH, contact time, biomass concentration, initial metal ion concentration, and presence of coions using driedOscillatoriasp. biomass as well as pretreatment on the biosorption capacity of the biomass were studied. Various pretreatments ofOscillatoriasp. increased biosorption of Cd(II) at pH 7 in comparison with native biomass. However, heating at 100°C in a water bath showed significant improvement in Cd(II) biosorption capacity. The experimental biosorption data was well fitted to the Freundlich model compared to the Langmuir model, and the amount of Cd(II) removed from solution increased with increasing Cd(II) concentration. In addition, the dried biomass was investigated for Cd(II) removal from the simulated real sample containing about 14 mg/l Cd(II) at pH 7, under the same experimental condition.


2007 ◽  
Vol 3 (1) ◽  
pp. 133-142 ◽  
Author(s):  
Ishaq Abdullah Zaafarany

Abstract          The kinetics of sol-gel transformation between A13+, La 3+ and Th4+ metal ion electrolytes and sodium alginate sol have been studied complexometrically at various  temperatures. In the presence of a large excess of sodium alginate sol concentration over that of metal ion electrolyte, the pseudo first–order plots of exchange showed sigmoidal curves with two distinct stages. The initial part was relatively fast and curved significantly at early times, followed by a slow decrease in the rates of exchange over longer time periods. The rate constants of gelation showed second-order overall kinetics which was first order in the concentration of both reactants. The thermodynamic parameters have been evaluated and tentative gelation mechanisms consistent with the kinetic results of gelation are suggested. The stability of these ionotropic metal-alginate complexes has been discussed in terms of the coordination geometry and strength of chelated bonds.


2015 ◽  
Vol 6 (2) ◽  
pp. 310-324 ◽  
Author(s):  
Selvaraj Dinesh Kirupha ◽  
Selvaraj Kalaivani ◽  
Thangaraj Vidhyadevi ◽  
Periyaraman Premkumar ◽  
Palanithamy Baskaralingam ◽  
...  

A novel poly [2,5-(1,3,4-thiadiazole)-benzalimine] abbreviated as TDPI adsorbent was synthesized using simple polycondensation technique. The synthetic route involves the preparation of 2,5-diamino-1,3,4-thiadiazole from 2,5-dithiourea and subsequent condensation with terephthalaldehyde. The resin was chemically characterized using Fourier transform infrared (FT-IR), 1H-NMR, and 13C-NMR spectroscopic analysis. Surface morphology and thermal stability were analyzed using scanning electron microscopy (SEM) and thermo-gravimetric analysis (TGA). The effect of the pH value of solution, contact time, adsorbent dose, and initial metal ion concentration were investigated by batch equilibrium adsorption experiments. Kinetic studies show that the adsorption of metal ions onto the resin proceeds according to the pseudo-second-order model and the equilibrium data were best interpreted by the Redlich–Peterson isotherm. The experimental values of the adsorption capacities of Pb2+, Cu2+, Ni2+, and Cd2+ on to TDPI could reach up to 437.2, 491.6, 493.7, and 481.9 mg.g−1 respectively. The exothermic nature of the process, the affinity of the adsorbent towards the metal ions and the feasibility of the process are explained in the thermodynamic parameters. The resin stability and re-usability studies suggest that the resin is chemically stable (0.3 N HCl and H2SO4) and could be regenerated without any serious decline in performance.


2020 ◽  
Vol 24 (2) ◽  
pp. 329-333
Author(s):  
D.O. Jalija ◽  
A . Uzairu

The objective of this study was to investigate the biosorption of Cu (II) and Ni (II) ions from aqueous solution by calcium alginate beads. The effects of solution pH, contact time and initial metal ion concentration were evaluated. The results showed that maximum Cu (II) removal (93.10%) occurred at pH of 9.0, contact time of 120 minutes and initial ion concentration of 10 mg/L while that of Ni (II) was 94.6%, which was achieved at pH of 8.0, contact time of 120 minutes and initial ion concentration of 10 mg/L. The equilibrium data fitted well to the Langmuir Isotherm indicating that the process is a monolayer adsorption. The coefficients of determination, R2, values for the Langmuir Isotherm were 0.9799 and 0.9822 respectively for Cu (II) and Ni (II) ions. The values of the maximum biosorption capacity, Qo, were 10.79 and 6.25 mgg-1 respectively. The kinetic data also revealed that the sorption process could best be described by the pseudo – second order kinetic model. The R2 values for the pseudo – second order kinetic plots for Cu (II) and Ni (II) were 0.9988 and 0.9969 respectively. These values were higher than those for the pseudo – first order plots. The values of the biosorption capacity qe obtained from the pseudo – second order plots were very close to the experimental values of qe indicating that the biosorption process follows the second order kinetics. This study has therefore shown that calcium alginate beads can be used for the removal of Cu (II) and Ni (II) ions from wastewaters. Keywords: Keywords: Adsorption, Calcium alginate, Isotherm, Langmuir, Pseudo- first order, Pseudo-second order


2012 ◽  
Vol 9 (3) ◽  
pp. 1389-1399 ◽  
Author(s):  
R. Hema Krishna ◽  
A. V. V. S. Swamy

The powder of mosambi fruit peelings (PMFP) was used as an adsorbent for the removal of heavy metal like Cr (VI) from aqueous solutions was studied using batch tests. The influence of physico-chemical key parameters such as the initial metal ion concentration, pH, agitation time, adsorbent dosage, and the particle size of adsorbent has been considered in batch tests. Sorbent ability to adsorb Cr (VI) ions was examined and the mechanism involved in the process investigated. The optimum results were determined at an initial metal ion concentration was 10 mg/lit, pH=2, agitation time – 60 min, an adsorbent dose (150 mg/50 ml) and the particle size (0.6 mm). The % adsorption, Langmuir constants [Q0=7.51(mg/g) and b=1.69(mg/lit)] Freundlich constant(Kf=2.94), Lagergren rate constants (Kad(min-1)=5.75 x 10-2) for [Cr(VI)] 10 mg/lit were determined for the adsorption system as a function of sorbate concentration. The equilibrium data obtained were tested using Langmuir, Freundlich adsorption isotherm models, and the kinetic data obtained were fitted to pseudo first order model.


2008 ◽  
Vol 58 (5) ◽  
pp. 1061-1069 ◽  
Author(s):  
Veronica Almaguer Cantu ◽  
Ma Teresa Garza-González ◽  
Javier Rivera de la Rosa ◽  
Jose Angel Loredo-Medrano

The biosorption of Pb2 +  and Cd2 +  in a fixed bed column by immobilised Chlorella sp. was characterised in a fixed bed column. Effect of initial concentration of Pb2 +  and Cd2 + , pH, and pellet size on the biosorption capacity was studied, at laboratory scale, using a factorial experiment design 23, in a 10 cm height × 1 cm of diameter continuous flow column packed with immobilised biomass. Equilibrium uptake of Pb2 +  and Cd2 + , increased with increasing initial metal ion concentration. It was favoured to pH 5, with a pellet of 5 mm of diameter. Langmuir model described the biosorption equilibrium of both metals. The biosorption of each single cation was studied too in a large column (50 cm height × 5 cm of diameter) at bench scale with a range of flow of 40 to 80 mL min−1. The mass transfer coefficient was determined fitting the experimental data to continuity equations that were discretised in the radial terms with orthogonal collocation method.


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