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

Abstract

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.

Flotation of Cadmium Ions from Wastewater Using Air Micro-Bubbles

“…These complexes can be less reactive or less accessible to the removal medium, reducing the efficiency of the removal process. This result agrees with the findings of [16,33,34,35]. 30 mg/L to 40 mg/L, the removal rate decreased from 95.44% to 80.69%, respectively, at the end of flotation time.…”

“…Figure 6. demonstrates that the Cd (II) ion was removed to 90.56% at 20 min for SDS 15mg/L and 96.01% as the highest value at the end of the float time, and by increasing C SDS to 20 mg/L the removal efficiency of Cd(II) ion was stopped at 65.39%, the competition between the metal-collector complex and free collector ions for bubble surface locations, as well as the abundance of collector, Micelles can form, which might result in potential toxicity from leftover collector in the effluent and also raise costs [16].…”

“…Microbubbles (30-100 μm) are used to recover fine mineral particles (<13 μm), which has shown to improve separation efficiency compared to larger bubbles. Injecting smaller bubbles further enhances the capture of ultrafine particles (<5 μm) by increasing the bubble surface flux and reducing the bubble size distribution through the injection of smaller bubbles [16]. Due to its small bubble scale, substantial interfacial area, lengthy stagnation period, high interior pressure, and high mass transfer rates, micro-bubble wastewater treatment is quite interesting [17].…”

Effective Removal of Ibuprofen from Aqueous Solution Using Cationic Surface-Active Agents in Dissolved Air-Flotation Process

“…After 20 psig, the rate of removal declines due to bubble coalescence ensuing in the dissemination of some of the contaminant-collector precipitates that get back into the bulk solution. As a consequence, there is an inadequate contact between the surface-active agent and the contaminant [54].…”

Three-Phase Three-Dimensional Electrochemical Process for Efficient Treatment of Greywater

“…Within this context, conventional biological treatment does not always achieve satisfactory results, and traditional physicochemical methods are relatively expensive, ineffective, or may lead to secondary contamination. For example, the dissolved air flotation method [ 14 , 15 , 16 ] involves injection of a large number of dense bubbles into treated wastewater, whereupon impurities adhere to the bubbles, effectively forming a liquid with a density less than that of water. The primary disadvantage of this treatment method is that it is difficult to directly contact the suspended sludge, which results in secondary sludge formation.…”