scholarly journals Micro-Bubble Flotation for Removing Cadmium Ions from Aqueous Solution: Artificial Neural Network Modeling and Kinetic of Flotation

2019 ◽  
Vol 20 (2) ◽  
pp. 1-9
Author(s):  
Abeer I. Alwared ◽  
Nada Abdulrazzaq ◽  
Baseem Al-Sabbagh

In this work, microbubble dispersed air flotation technique was applied for cadmium ions removal from wastewater aqueous solution. Experiments parameters such as pH (3, 4, 5, and 6), initial Cd(II) ions concentration (40, 80, and 120 mg/l)  contact time( 2, 5, 10 , 15, and 20min), and surfactant (10, 20and 40mg/l) were studied in order to optimize the best conditions .The experimental results indicate that microbubbles were quite effective in removing cadmium ions and the anionic surfactant SDS was found to be more efficient than cationic CTAB in flotation process. 92.3% maximum removal efficiency achieved through 15min at pH 5, SDS surfactant concentration 20mg/l, flow rate250 cm3/min and at 40mg/l Cd(II) ions initial concentration. The removal efficiency of cadmium ion was predicted through 11 neurons hidden layer, with a correlation coefficient of 0.9997 between ANN outputs and the experimental data and through sensitivity analysis, pH was found to be most significant parameter (25.13 %).The kinetic flotation order for cadmium ions almost first order and the removal rate constant (k) increases with decreasing the initial metal concentration.

2017 ◽  
Vol 76 (6) ◽  
pp. 1466-1473 ◽  
Author(s):  
M. H. Salmani ◽  
M. Mokhtari ◽  
Z. Raeisi ◽  
M. H. Ehrampoush ◽  
H. A. Sadeghian

Wastewater containing pharmaceutical residual components must be treated before being discharged to the environment. This study was conducted to investigate the efficiency of tungsten-carbon nanocomposite in diclofenac removal using design of experiment (DOE). The 27 batch adsorption experiments were done by choosing three effective parameters (pH, adsorbent dose, and initial concentration) at three levels. The nanocomposite was prepared by tungsten oxide and activated carbon powder in a ratio of 1 to 4 mass. The remaining concentration of diclofenac was measured by a spectrometer with adding reagents of 2, 2′-bipyridine, and ferric chloride. Analysis of variance (ANOVA) was applied to determine the main and interaction effects. The equilibrium time for removal process was determined as 30 min. It was observed that the pH had the lowest influence on the removal efficiency of diclofenac. Nanocomposite gave a high removal at low concentration of 5.0 mg/L. The maximum removal for an initial concentration of 5.0 mg/L was 88.0% at contact time of 30 min. The results of ANOVA showed that adsorbent mass was among the most effective variables. Using DOE as an efficient method revealed that tungsten-carbon nanocomposite has high efficiency in the removal of residual diclofenac from the aqueous solution.


Author(s):  
Abbas H. Sulaymon ◽  
Ahmed Abed Mohammed

The separation of emulsified kerosene in water (concentration 250-750ppm) was investigated in a bubble column15.6 cm diameter and 120 cm height. The effective behaviors of bubble characteristics (bubble diameter, bubble rise velocity and air hold-up) on the removal efficiency were measured by electroresistivity probe. The effects of kerosene concentration, air flow rate,bubble diameter, liquid height, liquid viscosity, NaCl concentration, and alum on the removal rate were found. The experimental results showed that the removal efficiency increased with increasing air flow rate (1.09-2.6cm/s) and decreased with increasing CMC concentration. The results also showed that adding anionic surfactants (SLES and SDBS) leads to increase removal rate. The the flotation process was found to be first order kinetics. New correlations of air holdup and bubble diameter using dimensionless groups were derived.


Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 781 ◽  
Author(s):  
Wang ◽  
Zhang ◽  
Lv

The removal efficiency and mechanism of Cr(VI) removal from aqueous solution on semi-decomposed maize straw biochars pyrolyzed at 300 to 600 °C were investigated. The removal of Cr(VI) by the biochars decreased with pyrolysis temperature increasing from 300 to 600 °C, and the maximum removal capacity of Cr(VI) for maize straw biochar pyrolyzed at 300 °C was 91 mg/g at pH 2.0. The percentage removal of Cr(VI) rapidly decreased with pH increasing from 2.0 to 8.0, with the maximum (>99.9%) at pH 2.0. The variation of Cr(VI) and Cr(III) concentrations in the solution after reaction showed that Cr(VI) concentration decreased while Cr(III) increased and the equilibrium was reached after 48 h, while the redox potential after reaction decreased due to Cr(VI) reduction. X-ray photoelectron spectroscopy (XPS) semi-quantitative analysis showed that Cr(III) accounted for 75.7% of the total Cr bound to maize straw biochar, which indicated reductive adsorption was responsible for Cr(VI) removal by the biochars. Cr(VI) was firstly adsorbed onto the positively charged biochar surface and reduced to Cr(III) by electrons provided by oxygen-containing functional groups (e.g., C=O), and subsequently part of the converted Cr(III) remained on the biochar surface and the rest released into solution. Fourier transform infrared (FTIR) data indicated the participation of C=O, Si–O, –CH2 and –CH3 groups in Cr(VI) removal by the biochars. This study showed that maize straw biochar pyrolyzed at 300 °C for 2 h was one low-cost and efficient adsorbent for Cr(VI) removal from aqueous solution.


2013 ◽  
Vol 48 (2) ◽  
pp. 121-132 ◽  
Author(s):  
S. Piel ◽  
S. Blondeau ◽  
J. Pérot ◽  
E. Baurès ◽  
O. Thomas

The adsorption of some major pharmaceutical products (sulfamethoxazole, caffeine, iopromide and carbamazepine) in water was evaluated using four types of activated carbon, three powdered activated carbon (PAC) and one fluidized, coagulated and flocculated activated carbon (FAC) extracted from a Carboplus®P pilot. These substances were the most frequently quantified (in 50% of samples at least) in surface waters of the Vilaine's basin (Brittany, France) during three sampling campaigns. Jar test experiments were carried out in order to assess the removal efficiency of the four activated carbons. Carbamazepine and caffeine were well removed with PAC with a maximum removal rate of 80% whereas it was more difficult for sulfamethoxazole and iopromide with a maximum of 39%. For each molecule, removal rates are clearly dependent on PAC nature. The overall results with FAC are clearly distinguishable from PAC tests with gains of performance on all target molecules (from 80 to >95%).


2015 ◽  
Vol 61 (6) ◽  
pp. 399-408 ◽  
Author(s):  
Huining Zhang ◽  
Li Liu ◽  
Qing Chang ◽  
Hongyu Wang ◽  
Kai Yang

The adsorption behavior of Cr(VI) ions from aqueous solution by a chromium-tolerant strain was studied through batch experiments. An isolate designated Zer-1 was identified as a species of Bosea on the basis of 16S rRNA results. It showed a maximum resistance to 550 mg·L−1 Cr(VI). The effects of 3 important operating parameters, initial solution pH, initial Cr(VI) concentration, and biomass dose, were investigated by central composite design. On the basis of response surface methodology results, maximal removal efficiency of Cr(VI) was achieved under the following conditions: pH, 2.0; initial concentration of metal ions, 55 mg·L−1; and biomass dose, 2.0 g·L−1. Under the optimal conditions, the maximum removal efficiency of Cr(VI) ions was found to be nearly 98%. The experimental data exhibited a better fit with the Langmuir model than the Freundlich model. The biosorption mechanisms were investigated with pseudo-first-order, pseudo-second-order, and intraparticle diffusion kinetics models. These results revealed that biosorption of Cr(VI) onto bacterial biomass could be an alternative method for the removal of metal ions from aqueous solution.


2006 ◽  
Vol 53 (7) ◽  
pp. 127-132 ◽  
Author(s):  
M.Y. Han ◽  
M.K. Kim ◽  
H.J. Ahn

Flotation is a water treatment alternative to sedimentation, and uses small bubbles to remove low-density particles from potable water and wastewater. The effect of zeta potential, bubble size and particle size on removal efficiency of the electro-flotation process was investigated because previous model-simulations indicated that these attributes are critical for high collision efficiency between micro-bubbles and particles. Solutions containing Al3 +  as the metal ion were subjected to various conditions. The zeta potentials of bubbles and particles were similar under identical conditions, and their charges were influenced by metal ion concentration and pH. Maximum removal efficiency was 98 and 12% in the presence and absence of flocculation, respectively. Removal efficiency was higher when particle size was similar to bubble size. These results agree with modelling simulations and indicate that collision efficiency is greater when the zeta potential of one is negative and that of the other is positive and when their sizes are similar.


2009 ◽  
Vol 620-622 ◽  
pp. 611-614
Author(s):  
Feng Liu ◽  
Xue Gang Luo ◽  
Xiao Yan Lin

Removal of Zn (II) from aqueous solution by copolymer of grafting acrylic acid onto deacetylated konjac glucomannan (GADKGM) was evaluated in a bath adsorption system. Operational parameters such as pH, time, temperature and initial concentration were studied in present work. The adsorption process was relatively fast and highly effective. Removal efficiency for Zn(II) solution at the concentration of 100 mg/L was 98% at optimum operational pH of 6. The removal rate for Zn(II) on GADKGM was very fast and the removal efficiency can attain about 90% within 5 min. Isotherm adsorption data were described by Langmuir model with monolayer adsorption capacity of 125 mg/g. The negative values of thermodynamic parameters of △Go and △So indicated that adsorption process was a spontaneous process and randomness at the solid/liquid interface was decreased during the adsorption process.


2011 ◽  
Vol 94-96 ◽  
pp. 995-998 ◽  
Author(s):  
Rui Min Mu ◽  
Gui Xia Ma ◽  
Xia Zhao

Lead(Ⅱ) is a typical industrial pollutant which is harmful to people’s health. In this study, a new environmental-friendly material, the edible biopolymer poly--glutamic acid (-PGA) was applied to adsorb lead(Ⅱ). The results revealed that -PGA had pronounced binding effects on lead(Ⅱ) and its metal adsorption capacity was affected by lead(Ⅱ) concentration, -PGA dose and pH of the solution. For lead(Ⅱ) concentration, the removal rate of lead(Ⅱ) increased with the decrease of the metal concentration. For -PGA dose, the removal rate of lead(Ⅱ) increased with the increase of -PGA dose until the turning point at 4000 mg/L and then the tendency was adverse. The maximum removal rate was 92.8 % when lead(Ⅱ) and -PGA concentration was 1000 mg/L and 4000 mg/L separately. For pH, the metal adsorption capacity was weak when pH<4 and the optimal result occurred at pH 5-6.


2011 ◽  
Vol 347-353 ◽  
pp. 89-93
Author(s):  
Ming Yang ◽  
Ying Hua Zhao ◽  
Ying Chen Zhang ◽  
Deng Xin Li

Expanded graphite (EG) was prepared by microwave irradiation at 1000 w for 60 s. It is a novel adsorbent for Sn (Ⅱ) adsorption. This paper aims to investigate the effect of the adsorption of EG. The adsorption behavior of Sn (Ⅱ) from aqueous solution onto EG was investigated with variety of parameters such as pH, adsorbents dosage, initial Sn (Ⅱ) concentration, contact time and temperature. On conditions that the pH was 2.5, the dosage of adsorbent was 0.02 g, the concentration of Sn (Ⅱ) was 200 mg/L and the temperature was 15°C, the maximum removal rate can reach to 98.32%, and the adsorption quantity can reach to 245.7985 mg•g-1. The results showed that the EG was an efficient and novel adsorbent for the removal of stannum from aqueous solution.


2013 ◽  
Vol 726-731 ◽  
pp. 2956-2959
Author(s):  
Yan Chen ◽  
Jing Wang ◽  
Rong Rong Su ◽  
Jia Quan Rao ◽  
Xiao Yan Lin

Effects of parameters including pH value, temperature, absorbent dosage, initial ion concentration, and absorbed time, on the removal efficiency of Ag+ from aqueous solution were investigated through single factor experiment. Vinasse before and after adsorption were characterized by IR. The maximum removal efficiency of Ag+ on vinasse is 97%. The equilibrium sorption is well demonstrated by Freundlich isotherm model.


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