Carbon dioxide activated biochar-clay mineral composite efficiently removes ciprofloxacin from contaminated water - Reveals an incubation study

2021 ◽  
pp. 130079
Author(s):  
Muhammad Arif ◽  
Guijian Liu ◽  
Muhammad Zia ur Rehman ◽  
Balal Yousaf ◽  
Rafay Ahmed ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Clay Mineral ◽  
Contaminated Water ◽  
Activated Biochar ◽  
Incubation Study

Mass Transfer From Single Carbon Dioxide Bubbles in Contaminated Water

2014 ◽  
Author(s):  
Jiro Aoki ◽  
Kosuke Hayashi ◽  
Shogo Hosoda ◽  
Shigeo Hosokawa ◽  
Akio Tomiyama
Keyword(s):  
Carbon Dioxide ◽  
Mass Transfer ◽  
Surfactant Concentration ◽  
Bubble Diameter ◽  
Surfactant Solution ◽  
Contaminated Water ◽  
Tail Region ◽  
Transfer Rates ◽  
Small Bubbles ◽  
Taylor Bubbles

Mass transfer from single carbon dioxide bubbles rising through contaminated water in a vertical pipe of 12.5 mm diameter was measured to investigate effects of surfactant. The bubble diameter was widely varied to cover various bubble shapes such as spheroidal, wobbling, cap and Taylor bubbles. The gas and liquid phases were 99.9 % purity carbon dioxide and a surfactant solution made of purified water and Triton X-100. Comparison of mass transfer rates between contaminated and clean bubbles made clear that the surfactant decreases the mass transfer rates of small bubbles. The Sherwood number of small bubbles in the extreme cases, i.e. zero and the highest surfactant concentrations, is well correlated in terms of the bubble Reynolds number, Schmidt number and the ratio, λ, of the bubble diameter to pipe diameter. The Sherwood numbers at intermediate surfactant concentration, however, are not well correlated using available correlations. The mass transfer rates of Taylor bubbles also decrease with increasing the surfactant concentration. They however increase with the diameter ratio and approaches that of clean Taylor bubbles as λ increases. The main cause of this tendency was revealed by interface tracking simulations, i.e. the surfactant adsorbs only in the bubble tail region and the nose-to-side region is almost clean at high λ.

Rising speed and dissolution rate of a carbon dioxide bubble in slightly contaminated water

1999 ◽  
Vol 378 ◽  
pp. 319-334 ◽  
Author(s):  
F. TAKEMURA ◽  
A. YABE
Keyword(s):  
Carbon Dioxide ◽  
Drag Coefficient ◽  
Dissolution Rate ◽  
Solid Particle ◽  
Sherwood Number ◽  
Ccd Camera ◽  
Numerical Results ◽  
Fluid Sphere ◽  
Contaminated Water ◽  
Cap Model

The rising speed and dissolution rate of a carbon dioxide bubble in slightly contaminated water were investigated experimentally and numerically. We developed an experimental system that uses a charged-coupled device (CCD) camera coupled with a microscope to track the rising bubble. By precisely measuring the bubble size and rising speed, we were able to accurately estimate the drag coefficient and the Sherwood number for the dissolution rate of gas bubbles at Reynolds numbers below 100 in the transient regime, where the bubble changes from behaving as a fluid sphere to behaving as a solid particle. We also numerically estimated the drag coefficient and Sherwood number of the ‘stagnant cap model’ by directly solving the coupled Navier–Stokes and convection–diffusion equations. We compared our experimental results with our numerical results and proposed equations for estimating the drag coefficient and Sherwood number of the bubble affected by contamination and clarified that the gas–liquid interface of the carbon dioxide bubble in water is immobile. We also show that the experimental and numerical results are in good agreement and the stagnant cap model can explain the mechanism of the transient process where the bubble behaviour changes from that of a fluid sphere to that of a solid particle.

Clay mineral precipitation and transformation during burial diagenesis

1985 ◽  
Vol 315 (1531) ◽  
pp. 91-105 ◽  
Keyword(s):  
Carbon Dioxide ◽  
Aqueous Solution ◽  
Organic Matter ◽  
Clay Minerals ◽  
Clay Mineral ◽  
Burial Depth ◽  
Burial Diagenesis ◽  
Mineral Precipitation ◽  
Water Ph ◽  
Trioctahedral Smectite

Detrital clay minerals alter systematically during burial diagenesis. Smectites evolve via intermediate ‘illite-smectites’ to illite. Trioctahedral ‘smectite-chlorites’ or ‘vermiculite-chlorites’ evolve towards true (polytype Ib) chlorites. In other reactions, authigenic clays (kaolinite, illite, chlorite) precipitate directly from aqueous solution rather than by continuous modification of some precursor lattice. In yet others, one mineral replaces another. Many of these reactions are influenced by organic matter and the various low molecular mass soluble products of its diagenetic and thermal maturation. Carbon dioxide and organic acids influence pore-water pH and this, in turn, affects the solubility of clay minerals. Trioctahedral phyllosilicates are particularly sensitive. In contrast, organic matter also acts as a reducing agent when iron (III) oxides are destabilized to produce Fe 2+ and a marked increase in alkalinity. This reaction stabilizes trioctahedral clays such as chamosite. The balance between these different reactions affects the course of clay mineral diagenesis and itself varies systematically with burial depth and temperature.

scholarly journals Remediation of Emerging Heavy Metals from Water Using Natural Adsorbent: Adsorption Performance and Mechanistic Insights

2021 ◽  
Vol 13 (16) ◽  
pp. 8817
Author(s):  
Mehak Nawaz Khan ◽  
Hidayat Ullah ◽  
Sundas Naeem ◽  
Jalal Uddin ◽  
Yasir Hamid ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Chemical Properties ◽  
Chemical Oxidation ◽  
Contaminated Water ◽  
Strong Impact ◽  
Potentially Toxic Metals ◽  
Natural Adsorbent ◽  
Activated Biochar ◽  
Wide Range ◽  
Before And After

The presence of potentially toxic metals in water causes a strong impact on environment and human health. In this study, activated biochar was produced by using chemical oxidation method from wheat straw as natural adsorbent and was employed for heavy metals competitive remediation. The morphology, structure, and chemical properties of biochar before and after adsorption were characterized by FTIR, XRD, SEM and EDX mapping techniques. The competitive adsorption efficiency of adsorbent for divalent cadmium (Cd) and lead (Pb) from contaminated water was investigated by using wide range of several initial metal concentration, contact time and pH. Maximum adsorption of Cd(II) and Pb(II) was found in the pH range of 6–8. The adsorption capacity for Cd(II) and Pb(II) was 8.85 and 9.03 mg/g, respectively. Thermodynamics parameters and kinetic models were applied to adsorption data. The isotherm data followed Langmuir model, corresponding to monolayer adsorption of the two ions in the contaminated water. The kinetic data followed the pseudo 2nd order kinetics model, which authenticates the chemisorption nature. The thermodynamic study indicated that Cd adsorption is a spontaneous exothermic process while Pb adsorption is an endothermic process. Mineral precipitation, surface complexation, and cation-π interactions are the major remediation strategies for Cd(II) and Pb(II).

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