Partial carbonized nanoporous resin for uptake of lead from aqueous solution

2015 ◽  
Vol 72 (6) ◽  
pp. 974-982 ◽  
Author(s):  
I. Ghiloufi ◽  
A. S. AL-Hobaib ◽  
L. El Mir

Four partial carbonized nanoporous resins (PCNRs), based on organic xerogel compounds, were synthesised by the sol–gel method from pyrogallol and formaldehyde mixtures in water using picric acid as catalyst. The PCNRs were prepared at different pyrolysis temperatures: T1 = 200 °C (PF-200), T2 = 300 °C (PF-300), T3 = 400 °C (PF-400), or T4 = 500 °C (PF-500). The PCNRs were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier transformed infrared spectroscopy, and nitrogen porosimetry. The obtained results show that PF-200 is more efficient for the removal of Pb2+ from aqueous solution than the other adsorbent prepared in this study. The characteristics of lead uptake by PF-200 were explored using well-established and effective parameters including pH, contact time, initial metal ion concentration and temperature. Optimum adsorption of Pb2+, using PF-200, was observed at pH 4.5. The Langmuir model gave a better fit than the other models, and kinetic studies revealed that the adsorption was well fitted by the pseudo second-order kinetic model and thermodynamic properties, i.e., Gibbs free energy change, enthalpy change and entropy change, showed that adsorption of Pb2+ onto PF-200 was endothermic, spontaneous and feasible in the temperature range of 298–328 K.

2015 ◽  
Vol 10 (3) ◽  
pp. 729-737
Author(s):  
Imed Ghiloufi

Partial carbonized nanoporous resin (PCNR-150), based on organic xerogel compounds, was prepared at 150 ºC by sol–gel method from pyrogallol and formaldehyde mixtures in water using perchloric acid as catalyst. The PCNR-150 was characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier transformed infrared spectroscopy (FTIR) and nitrogen porosimetry. The metal uptake characteristics were explored using well-established and effective parameters including pH, contact time, initial metal ion concentration, and temperature. Optimum adsorptions of Co2+ and Ni2+, using PCNR-150 as adsorbent, were observed at pH 5 and 7, respectively. Langmuir model gave a better fit than the other models, and kinetic studies revealed that the adsorption is fast and its data are well fitted by the pseudo-second-order kinetic model and thermodynamic properties, i.e., ΔGo, ΔHo, and ΔSo, showed that adsorption of Co2+ and Ni2+ onto PCNR-150 was endothermic, spontaneous and feasible in the temperature range of 300–328 K.


2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Muhammad Hamid Raza ◽  
Aqsa Sadiq ◽  
Umar Farooq ◽  
Makshoof Athar ◽  
Tajamal Hussain ◽  
...  

Batch scale studies for the adsorption potential of novel biosorbentPhragmites karka(Trin), in its natural and treated forms, were performed for removal of mercury ions from aqueous solution. The study was carried out at different parameters to obtain optimum conditions of pH, biosorbent dose, agitation speed, time of contact, temperature, and initial metal ion concentration. To analyze the suitability of the process and maximum amount of metal uptake, Dubinin-Radushkevich (D-R) model, Freundlich isotherm, and Langmuir isotherm were applied. The values ofqmaxfor natural and treated biosorbents were found at 1.79 and 2.27 mg/g, respectively. The optimum values of contact time and agitation speed were found at 50 min and 150 rpm for natural biosorbent whereas 40 min and 100 rpm for treated biosorbent, respectively. The optimum biosorption capacities were observed at pH 4 and temperature 313 K for both naturalP. karkaand treatedP. karka.RLvalues indicate that comparatively treatedP. karkawas more feasible for mercury adsorption compared to naturalP. karka. Both pseudo-first-order and pseudo-second-order kinetic models were applied and it was found that data fit best to the pseudo-second-order kinetic model. Thermodynamic studies indicate that adsorption process was spontaneous, feasible, and endothermic.


2010 ◽  
Vol 2010 ◽  
pp. 1-6 ◽  
Author(s):  
Satoshi Tanimoto ◽  
Yasushi Nakamura ◽  
Hitoshi Yamaoka ◽  
Yoshitsugu Hirokawa

Terpyridine-polyethyleneglycol-block-polyleucine block copolymer (tpy-PEG-PLeu) was synthesized by a ring-opening polymerization of L-leucine -carboxyanhydride. The copolymer complexed with ion and its aqueous solution showed a purple color as a result of the complexation. This complexation caused the diblock/triblock structural transition of the copolymer. The change of the aggregation behavior caused by the structural transition was observed by a dynamic light scattering apparatus. The diblock tpy-PEG-PLeu copolymer formed a micelle in the aqueous solution. On the other hand, the triblock-type copolymer, after the complexation, formed the micelle structures and huge aggregates, which is considered to be a network structure. The complexation of the diblock tpy-PEG-PLeu copolymer with Fe ion is consequently considered to be a trigger of the gelation.


2015 ◽  
Vol 4 (3) ◽  
pp. 277 ◽  
Author(s):  
Kouoh Sone Paul-Michel Adolphe ◽  
Tagne Guy Merlain ◽  
Lekene Ngouateu René Blaise ◽  
Belibi Belibi Placide Desire ◽  
NdiNsami Julius ◽  
...  

<p>The present paper reports on the kinetic and equilibrium studies of the adsorption of Nickel(II) ions from aqueous solution onto modified natural iron oxide (NAT) from Mbalam (East Region of Cameroon) and synthetic iron oxide (SYNTH). The parameters investigated using batch techniques include, the contact time, adsorbent mass, pH and initial metal ion concentration. The experimental results obtained showed that, the optimum pH of 6 for bothadsorbents with an equilibrium time of 30 minutes was sufficient. The kinetic data correlated well with the pseudo-first-order and pseudo-second-order kinetic models for both the adsorbents based on the correlation coefficients (R<sup>2</sup>) obtained. The adsorption processes followed both the Langmuir and the Tempkin adsorption models for the natural iron oxide, whereas the Freundlich and Tempkin adsorption models fitted well the adsorption data for the synthetic iron oxide. The maximum quantity of Nickel(II) ions adsorbed was 250 mg/g for the two adsorbents. These results revealed a high adsorption capacity of natural iron oxide which is comparable to that of synthetic iron oxide.</p>


Author(s):  
Adewale Adewuyi ◽  
Fabiano Vargas Pereira ◽  
Omotayo Anuoluwapo Adewuyi

Kaolinite clay (KC) obtained from redemption camp; Nigeria was modified by surface grafting and investigated for the removal of Pb2+ and Cd2+ ions from aqueous solution by adsorption. KC and the modified kaolinite clay (MKC) were characterized using X-ray Diffraction analysis (XRD), Scanning Electron Microscopy (SEM), Brunauer-Emmett-Teller (BET) surface area analyzer, Fourier Transform Infrared spectrometer (FTIR), Particle Size Distribution (PSD), zeta potential, elemental analysis (CHNS/O analyzer) and Energy Dispersive Spectroscopy (EDS). Equilibrium, thermodynamics and kinetic studies were conducted by considering the effects of pH, initial metal ion concentration, contact time, adsorbent weight and temperature. Modification of KC increased its equilibrium adsorption capacity from 8.01 mg/g for Cd2+ and from 24.75 mg/g to 36.41 mg/g for Pb2+ ions. The adsorption process obeys Freundlich and Temkin isotherms. The adsorption was second-order-kinetic and controlled by both intra-particle and liquid film diffusion. Values of ΔGo, ΔHo, and ΔSo, for KC an MKC showed a stable adsorbent-adsorbate configuration.


2013 ◽  
Vol 66 (2) ◽  
pp. 227 ◽  
Author(s):  
Maja N. Stanković ◽  
Nenad S. Krstić ◽  
Ian J. Slipper ◽  
Jelena Z. Mitrović ◽  
Miljana D. Radović ◽  
...  

The ability of a biosorbent based on a chemically modified Lagenaria vulgaris shell for CuII ion removal from aqueous solution was studied in batch conditions. The biosorbent was characterized by Fourier-transform infrared spectroscopy and the effect of relevant parameters such as contact time, pH, biomass dosage, and initial metal ion concentration was evaluated. The sorption process was found to be fast, attaining equilibrium within 40 min, and results were found to be best fitted by a pseudo-second order kinetic model. Experimental data showed that the biosorption is highly pH dependent, and the optimal pH was 5.0. Results were analyzed in terms of the following adsorption isotherms: Langmuir, Freundlich, Temkin, and Flory–Huggins, by a linear regression method. The CuII biosorption followed the Langmuir isotherm model (r2 = 0.998) with the maximum sorption capacity of 14.95 mg g–1. The methyl-sulfonated Lagenaria vulgaris biomass investigated in this study exhibited a high potential for the removal of CuII from aqueous solution.


2008 ◽  
Vol 5 (4) ◽  
pp. 761-769 ◽  
Author(s):  
S. Madhavakrishnan ◽  
K. Manickavasagam ◽  
K. Rasappan ◽  
P. S. Syed Shabudeen ◽  
R. Venkatesh ◽  
...  

Activated carbon prepared from Ricinus communis Pericarp was used to remove Ni(II) from aqueous solution by adsorption. Batch mode adsorption experiments are carried out by varying contact time, metal-ion concentration, carbon concentration and pH to assess kinetic and equilibrium parameters. The adsorption data were modeled by using both Langmuir and Freundlich classical adsorption isotherms. The adsorption capacity (Qo) calculated from the Langmuir isotherm was 31.15 mg/g of activated carbon at initial pH of 5.0±0.2 for the particle size 125-250 µm.


Author(s):  
F. U. Okwunodulu ◽  
H. O. Chukwuemeka-Okorie ◽  
N. M. Mgbemena ◽  
J. B. I. Kalu

The removal of Cr6+ from aqueous solution using unmodified and hydrochloric modified African nutmeg pod was studied. The effects of particle size, pH and initial metal ions concentration adsorbed were investigated. The amount of metal ion adsorbed increased as the initial metal ion concentration increased and also decreased at low pH of 2 for both modified and unmodified African nutmeg pod.  400 µm and 250 µm were the optimum particle sizes for both modified and unmodified African nutmeg pod respectively, values given as 75.8 mg/g for the modified and 93.39 mg/g for the unmodified. Generally, it was observed that the unmodified African nutmeg pod showed greater adsorption capacity than the modified African nutmeg pod. The equilibrium experimental data were examined via Langmuir and Freundlich isotherm models.  Freundlich isotherm model gave the best fit for the data in both unmodified and modified African nutmeg pod based on the correlation coefficients (R2 values) gotten. The results of the study showed that the African nutmeg pod is efficient for the removal of Cr6+ from aqueous solutions especially when unmodified.


2022 ◽  
Vol 0 (0) ◽  
Author(s):  
Md. Nabul Sardar ◽  
Nazia Rahman ◽  
Shahnaz Sultana ◽  
Nirmal Chandra Dafader

Abstract This study focuses on the adsorption of hazardous Cr (III) and Cu (II) ions from aqueous solution by applying modified waste polypropylene (PP) fabric as an adsorbent. Pre-irradiation technique was performed for grafting of sodium styrene sulfonate (SSS) and acrylic acid (AAc) onto the PP fabric. The monomer containing 8% SSS and 16% AAc in water was used. Graft yield at 30 kGy radiation dose was 390% when 4% NaCl was added as additive. The prepared adsorbent was characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), thermo-gravimetric analysis (TGA) and dynamic mechanical analyzer (DMA). The influences of different parameters including pH, contact time, temperature and initial metal ion concentration were also investigated. The equilibrium adsorption data were better fitted to the Langmuir isotherm model with maximum monolayer adsorption capacity 384.62 mg/g for Cr (III) and 188.68 mg/g for Cu (II) ions. The kinetic data were better explained by pseudo first-order kinetic model having good matching between the experimental and theoretical adsorption capacity. The adsorption process was spontaneous, endothermic and thermodynamically feasible. Furthermore, investigation of desorption of metal ions and reuse of the adsorbent suggesting that the adsorbent is an efficient and alternative material in the removal of Cr (III) and Cu (II) from aqueous media.


This study showed that kaolinite clay modified with Moringa oleifera pods is a promising low cost adsorbent for the removal of metals from aqueous solution because the resultant composite has higher adsorption capacities, and hence a better metal ions removal efficiency. The efficiencies of these adsorbents for the removal of Pb (II) and Cd (II) ions from aqueous solutions were studied as a function of pH, time, adsorbate concentration and adsorbent dose. Adsorption results showed that pH did significantly affect removal of heavy metal ions between pH 3 and 6. Increasing contact time and initial metal ion concentration increased the sorption capacity of the adsorbent for the metal ions. Adsorbent dosage indicated mainly surface phenomena involving sharing of electrons between the adsorbent surface and the metal ion species. The adsorption of metal ions from aqueous solutions of both metal ions at different initial metal ion concentrations reduced the initial adsorption rates of the adsorption of Pb (II) and Cd (II) by unmodified and modified kaolinite clay.


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