Removal of lead from aqueous solutions by complexation ultrafiltration with chitosan

2011 ◽  
Vol 11 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Jiahui Shao ◽  
Zhangwang Xie ◽  
Yiliang He ◽  
Guowai Liu
Keyword(s):  
Aqueous Solutions ◽  
Electrolyte Concentration ◽  
Removal Rate ◽  
Background Electrolyte ◽  
Transmembrane Pressure ◽  
Lead Removal ◽  
Dilute Solutions ◽  
Step Process ◽  
Nacl Concentration ◽  
Removal And Recovery

The removal of lead from aqueous dilute solutions by complexation-ultrafiltration with chitosan was studied. Experiments were performed as a function of aqueous pH, chitosan/Pb2+ ratio, and background electrolyte concentration. The value of pH was found to be the most important parameter to effect the lead removal. The lead removal rate reaches the plateau at almost 100% when the chitosan and lead ratio goes more than 4.0 at pH 6.0. With transmembrane pressure (TMP) 0.1 MPa, chitosan/Pb2+ ratio 4 and pH 6, the lead removal rate decreases sharply from 99.2% to 19.5% as the adding NaCl concentration increases from 0 to 500 mmol. The regeneration of the chitosan by acidification using diafiltration technique was further performed. In the end, the effect of regenerated chitosan on the lead removal was evaluated. At the optimum experimental condition of pH 6.0, regenerated chitosan/Pb2+ ratio 4 and TMP 0.10 MPa, the lead removal rate was found to be 96.2%, which is almost the same as that obtained on the original chitosan. The overall results from the two-step process of complexation-UF and decomplexation-UF separation showed that it could be a promising method for lead removal and recovery from aqueous solutions.

The interaction of a humic acid with heavy metals

Soil Research ◽  
1997 ◽  
Vol 35 (1) ◽  
pp. 89 ◽  
Author(s):  
K. M. Spark ◽  
J. D. Wells ◽  
B. B. Johnson
Keyword(s):  
Heavy Metals ◽  
Humic Acid ◽  
Functional Group ◽  
Electrolyte Concentration ◽  
Background Electrolyte ◽  
Metal Hydroxides ◽  
Step Process ◽  
Ph Values ◽  
Major Functional Group ◽  
Ph Range

The solubility of a coal humic acid and the sorption of heavy metals (Cu(II), Zn(II), Co(II), and Cd(II)) in the absence and presence of the humic acid were determined as a function of pH and concentration of background electrolyte. The solubility of the humic acid at low electrolyte concentration increases in a 2-step process with increase in pH. About 80% dissolves in the pH region 3–8·5, and the remainder in the region pH >8·5. The sorption of metals occurs at pH values significantly lower than those associated with the formation of insoluble metal hydroxides, with a maximum occurring in the pH region 5·5–7·5, and involves the solid state fraction of the humic acid. At the higher electrolyte concentration, the solubility of the humic acid is again a 2-step process but the increase in acid solution occurs over a relatively narrow pH range (5–6). At high pH, the presence of the humic acid significantly reduces the precipitation of the metals at both low and high salt concentration, probably due to the formation of soluble metal–humate species. There is evidence to suggest that the major functional group of the humic acid with which the metal cations interact is the carboxyl group.

Synthesis and Characterization of Chitosan templated Mesoporous Silica: Efficient use of Mesoporous Silica in the removal of Cu(II) from Aqueous Solutions

2016 ◽  
Vol 4 (2) ◽  
pp. 105-112
Author(s):  
Lalchhing puii ◽  
◽  
Seung-Mok Lee ◽  
Diwakar Tiwari ◽  
◽  
...  
Keyword(s):  
Mesoporous Silica ◽  
Aqueous Solutions ◽  
Background Electrolyte ◽  
Second Order ◽  
Order Kinetic ◽  
Sorption Data ◽  
Column Reactor ◽  
Wide Ph Range ◽  
Freundlich Adsorption Isotherm ◽  
Pseudo Second Order

A mesoporous silica was synthesized by annealing (3-Aminopropyl) triethoxysilane grafted chitosan at 800˚C. The mesoporous silica was characterized by the XRD (X-ray diffraction) analysis. The BET specific surface area and pore size of silica was found to be 178.42 m2/g and 4.13 nm. The mesoporous silica was then employed for the efficient remediation of aqueous solutions contaminated with Cu(II) under batch and column reactor operations. The mesoporous silica showed extremely high per cent removal of Cu(II) at wide pH range i.e., pH ~2.0 to 7.0. Relatively a fast uptake of Cu(II) was occurred and high percentage removal was obtained at initial concentrations studied from 1.0 to 15.0 mg/L. The equilibrium state sorption data were utilized for the Langmuir and Freundlich adsorption isotherm studies. Moreover, the effect of an increase in background electrolyte concentrations from 0.0001 to 0.1 mol/L NaNO3 was assessed for the uptake of Cu(II) by mesoporous silica. The equilibrium sorption was achieved within 240 min of contact and the kinetic data is best fitted to the pseudo-second-order and fractal like pseudo-second-order kinetic models. In addition, the mesoporous silica was used for dynamic studies under column reactor operations. The breakthrough curve was then used for the non-linear fitting of the Thomas equation and the loading capacity of the column for Cu(II) was estimated.

scholarly journals Study on the effect of electrocatalytic oxidation treatment of 2,4,6-Trinitrophenol wastewater

2018 ◽  
Vol 238 ◽  
pp. 03003
Author(s):  
Yaling Li ◽  
Wenqiang Jiang ◽  
Ruyu Li
Keyword(s):  
Current Density ◽  
Electrocatalytic Oxidation ◽  
Electrolyte Concentration ◽  
Removal Rate ◽  
Pharmaceutical Chemical ◽  
Oxidation Treatment ◽  
Titanium Electrode ◽  
First Order Kinetics ◽  
Oxidation Technology ◽  
Aromatic Nitro

2,4,6-Trinitrophenol is a toxic aromatic nitro-compounds that widely used in pharmaceutical, chemical and pesticide production. Due to its stable structure and poor biodegradability, advanced electrocatalytic oxidation technology was selected to treat simulated wastewater. The goal of the present work is to optimize the electrolysis conditions such as current density, electrolysis pH, and electrolyte concentration. A Pt modified TiO2 electrode was chosen as the anode accompanied with a titanium electrode of the same size as the cathode The results showed that the removal efficiency of 2,4,6-Trinitrophenol was the highest when the current density was 20mA/cm2, electrolyte pH=5, electrolyte concentration was 2 g/L. Under the optimal condition, the removal rate of 2,4,6-Trinitrophenol reached 99.76% after 120 minutes electrolysis. The decay of TNP could also be described by the pseudo-first-order kinetics formula with respect to TNP concentration. Therefore, electrocatalytic oxidation technology might provide an effective method for the degradation of nitroaromatic organic compounds.

Mercury removal and recovery from aqueous solutions by coupled complexation–ultrafiltration and electrolysis

2004 ◽  
Vol 229 (1-2) ◽  
pp. 179-186 ◽  
Author(s):  
J Barron-Zambrano ◽  
S Laborie ◽  
Ph Viers ◽  
M Rakib ◽  
G Durand
Keyword(s):  
Aqueous Solutions ◽  
Mercury Removal ◽  
Removal And Recovery

scholarly journals Photoreduction of Cr(VI) Ions in Aqueous Solutions by UV/ Photocatalytic Processes

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Chih Ming Ma ◽  
Yung Shuen Shen ◽  
Po Hsiang Lin
Keyword(s):  
Aqueous Solutions ◽  
Reaction Rate ◽  
Removal Rate ◽  
Experimental Results ◽  
Order Kinetic ◽  
Solution Ph ◽  
Relationship Of ◽  
The Relationship ◽  
Photocatalytic Processes ◽  
Order Kinetic Equation

This study discussed the photoreduction of Cr(VI) ions in aqueous solutions by UV/TiO2photocatalytic processes under various operational factors. Experimental results showed that the removal rate of Cr(VI) increased with decreasing solution pH values and with increasing dosages of organic compounds, indicating that the recombination rate of electrons and h+can be retarded in the reaction systems by the addition of the scavenger, thus raising the reaction rate of Cr(VI). The relationship of the chemical reaction rate of Cr(VI), TiO2dosage, and changes of Cr(VI) concentration was expressed by the pseudo-first-order kinetic equation. Comparing the experimental results of two different doping metals in modified TiO2photoreduction systems, the removal rate of Cr(VI) by the Ag/TiO2process is larger, possibly because the electron transferring ability of Ag is superior to that of Cu. However, the photoreduction rates of Cr(VI) by modified UV/TiO2processes are worse than those by a nonmodified commercial UV/TiO2process.

scholarly journals Synthesis of Mn(II)-containing paratungstate B from aqueous solutions acidified by acetic acid

2021 ◽  
pp. 39-48
Keyword(s):  
Thermal Analysis ◽  
Acetic Acid ◽  
Aqueous Solutions ◽  
Equilibrium Constants ◽  
Background Electrolyte ◽  
Equilibrium Processes ◽  
Transformation Processes ◽  
Paratungstate B ◽  
Solution Acidity ◽  
Tungstate Anion

The method of pH-potentiometric titration and mathematical simulation were used to study the equilibrium processes in aqueous solutions of the WO42––CH3COOH–H2O system in the acidity range Z=(CH3COOH)/(Na2WO4)=0.8–1.7 at СW=0.01 mol L–1 and T=2980.1 K, a constant ionic strength being maintained by sodium nitrate as a background electrolyte ((NaNO3)=0.10 mol L–1). We developed the models of polyoxotungstate anions formation and the equilibrium transformation processes, which adequately describe experimental pH vs. Z dependences. It was found that acetic acid using to create the solution acidity that is necessary for the formation of isopoly tungstate anion contributes only to the formation of protonated paratungstate B anions Нх[W12O40(ОН)2](10–х)– (where x=0–4). We calculated the logarithms of the concentration equilibrium constants of the polyanion formation and plotted the distribution diagrams. Double sodium-manganese(II) paratungstate B Na8(H2O)28Mn(H2O)2[H2W12O42]4H2O was synthesized at Z=1.00 to confirm the results of the mathematical modeling. The chemical composition of the prepared salt was established by chemical elemental analysis, thermal analysis, FTIR spectroscopy, and single crystal X-ray analysis. The stepwise process of salt dehydration was studied by means of differential thermal analysis.

scholarly journals Treatment of Synthetic Produced Water using Hybrid Membrane Processes

2018 ◽  
Vol 22 (2) ◽  
Author(s):  
N. Chin ◽  
S. O. Lai ◽  
K. C. Chong ◽  
S. S. Lee ◽  
C. H. Koo ◽  
...  
Keyword(s):  
Tio2 Nanoparticles ◽  
Produced Water ◽  
Removal Rate ◽  
Pure Water ◽  
Water Flux ◽  
Transmembrane Pressure ◽  
Oil Removal ◽  
Permeate Flux ◽  
Uf Membranes ◽  
Pes Membrane

The study was concerned with the treatment of tank dewatering produced water using hybrid microfiltration (MF) and ultrafiltration (UF) processes. The pre-treatment MF membrane was fabricated with polyethersulfone (PES), n-methyl-2-pyrrolidone (NMP) and polyvinylpyrrolidone (PVP). The UF membranes meanwhile contained additional component, i.e., titanium dioxide (TiO2) nanoparticles in the range of zero to 1.0 wt.%. The membrane performances were analysed with respect to permeate flux, oil removal and flux recovery ratio. An increase in TiO2 nanoparticles enhanced the pore formation, porosity and pure water permeability due to improved hydrophilicity. The permeate flux of UF membranes increased with the increase of TiO2 nanoparticles and pressure. The oil removal rate by MF process was only 52.35%, whereas the oil rejection efficiency was between 82.34% and 95.71% for UF process. It should be highlighted that the overall oil removal rate could achieve as high as 97.96%. Based on the results, the PES membrane incorporated with 1.0 wt.% TiO2 was proved to be the most promising membrane at a transmembrane pressure of 3 bar. Although 1.0 M NaOH solution could be used as cleaning agent to recover membrane water flux, it is not capable of achieving good results as only 52.18% recovery rate was obtained.

Sign in / Sign up

Export Citation Format

Share Document