scholarly journals Study of Cadmium Desorption Kinetics from Riverine Sediments

2021 ◽  
Author(s):  
Mohsen Nasrabadi ◽  
Mohammad Hossein Omid ◽  
Ali Mahdavi Mazdeh
Keyword(s):  
Metal Ions ◽  
Cadmium Concentration ◽  
Contaminated Sediments ◽  
Desorption Kinetics ◽  
Desorption Rate ◽  
Cadmium Ions ◽  
River Bed ◽  
Constant Rate ◽  
Natural Streams ◽  
Sediment Particles

Abstract In natural streams, the majority of heavy metal ions are generally associated ‎with ‎sediment particles. Under some environmental conditions, these metal ions may release from ‎the ‎sediment particles.‎ In such conditions, the desorption rate of heavy metals is very important for decision-makers of ‎water quality assessment. In this study, the effect of cadmium desorption ‎from the river bed ‎sediments has been ‎experimentally investigated. Artificially contaminated sediments were used ‎for performing batch desorption ‎experiments. The experiments were conducted by adding 1 gr of contaminated ‎sediment (D50 = 0.53 mm) with a known concentration and shaking until observing a ‎roughly ‎constant cadmium concentration in the solution. It was concluded that the cadmium ions were strongly bond to the river bed sediment; meanwhile, at the ‎equilibrium time, up to about 7 to 29 percent of cadmium ions were ‎released from the‎ artificially contaminated sediments. The experiments were followed by ‎two agitation rates of 100 and 200 rpm. It was revealed that by increasing the flow turbulence, the amount ‎of desorbed cadmium is slightly increased. Besides, the desorption kinetics was evaluated using eight models of Zero-, first-, second-, third-order, ‎parabolic diffusion, double parabolic diffusion, two constant rate, and simple Elovich. The results of the evaluation showed that simple Elovich (with R2 = 0.991), double parabolic diffusion (with R2 = 0.9882), two constant rate (with R2 = 0.983) and parabolic diffusion models (with R2 = 0.846) have respectively the best performance in calculation of Cd desorption rate from the sediments.

Factors Influencing Desorption of Mercury from Bed Sediments

1975 ◽  
Vol 12 (6) ◽  
pp. 1036-1040 ◽  
Author(s):  
Akira Kudo ◽  
D. C. Mortimer ◽  
J. Sanford Hart
Keyword(s):  
Environmental Conditions ◽  
Total Mercury ◽  
Exposure Period ◽  
Desorption Rate ◽  
Overlying Water ◽  
Bed Sediments ◽  
Ottawa River ◽  
Factors Influencing ◽  
River Bed

The desorption rate of mercury from bed sediments was determined by a 10 week experiment. The rates ranged from 0.1 ng/cm2/day to 1.0 ng/cm2/day for Ottawa River bed sediments, depending on the environmental conditions. The rates decreased with an increase of exposure period to the water, but increased with an increase in the depth of bed sediments. The amount of mercury desorbed from bed sediments to overlying water was highly dependent on the volume (depth) of bed sediments. Calculations based on the experiment showed the half-lives of total mercury associated with bed sediments from as short as 2.1 years to as long as 1.8 × 102 years, depending on the depth of the bed sediments.

scholarly journals Effect of organic substances on iron-release kinetics in a calcareous soil after basil harvesting

2018 ◽  
Vol 83 (7-8) ◽  
pp. 941-952
Author(s):  
Sedigheh Safarzadeh ◽  
Sadegh Kasmaei ◽  
Abadi Ahmad
Keyword(s):  
Calcareous Soil ◽  
Release Kinetics ◽  
Field Capacity ◽  
Ocimum Basilicum ◽  
Soil Samples ◽  
Desorption Kinetics ◽  
Organic Substances ◽  
Diethylenetriaminepentaacetic Acid ◽  
Iron Release ◽  
Constant Rate

Desorption of iron from soil is important for evaluating the availability and toxicity of soil Fe in agriculture. The aim of this investigation was to study the effect of organic substances (cow and sheep manures and vermicompost) on Fe release from a calcareous soil and determine the best models for the description of the Fe desorption kinetics. Organic substances were added to soils at the rate of 3 %. Basil (Ocimum basilicum L.) seeds were sown in each pot and pots were kept at 24?25?C at about field capacity for 90 days. After 90 days, plants were harvested and soil samples were used for Fe desorption analysis. Seven kinetic models were evaluated to describe the rate of Fe desorption in soil extracted with diethylenetriaminepentaacetic acid (DTPA). Results showed that Fe release from soil samples increased with time. Release of Fe was rapid at first and then became slower. Iron release in the organic substances treatments was higher than in the unamended soil and the two-constant rate, parabolic diffusion and simple Elovich models were the best equations for the description of Fe release from soils.

scholarly journals Removal of Lead and Cadmium Ions from Aqueous Solution by Adsorption on a Low-Cost Phragmites Biomass

Processes ◽  
2019 ◽  
Vol 7 (7) ◽  
pp. 406 ◽  
Author(s):  
Abdulaziz N. Amro ◽  
Mohammad K. Abhary ◽  
Muhammad Mansoor Shaikh ◽  
Samah Ali
Keyword(s):  
Aqueous Solution ◽  
Metal Ions ◽  
Surface Area ◽  
Metal Ion ◽  
Low Cost ◽  
Waste Water Treatment ◽  
Study Data ◽  
Small Surface ◽  
Cadmium Ions ◽  
Lead And Cadmium

In recent years, the interest in waste water treatment increased to preserve the environment. The objective of this study is the removal of lead and cadmium ions from aqueous solution by treated Phragmites biomass (TPB). TPB was characterized by using Fourier transform infrared spectroscopy (FTIR) and energy dispersive X-ray analysis (EDS) which indicates the presence of functional groups that may be responsible of metal adsorption such as hydroxyl, carbonyl, sulfonate and carboxylate. Characterization by scanning electron microscopy (SEM) and surface area analysis using the Brunauer–Emmett–Teller method (BET) illustrated that TPB is nonporous with a small surface area. The influences of various experimental factors were investigated; the proposed method recommended the extraction of Pb+2 and Cd+2 metal ions by TPB at pH 5.0. A contact time of 60 and 45 min was required for the adsorption 50 mL (50 ppm) Pb+2 and Cd+2 respectively to reach equilibrium when 0.10 g TPB was used. The optimum TPB dosage was 0.20 g for adsorption both metal ions when adsorbate solution was 50 mL (50 ppm). Particle sizes of 0.125–0.212 mm showed the best metal ion removal of both metal ions. Thermodynamic study illustrated that both metal ions correlate more with Langmuir isotherm. Furthermore, chemisorption of Pb+2 and Cd+2 on TPB was more likely according to kinetic study data.

Congener Level PCB Desorption Kinetics of Field-Contaminated Sediments

1999 ◽  
Vol 8 (5) ◽  
pp. 593-613 ◽  
Author(s):  
Upal Ghosh ◽  
A. Scott Weber ◽  
James N. Jensen ◽  
John R. Smith
Keyword(s):  
Contaminated Sediments ◽  
Desorption Kinetics ◽  
Kinetics Of

scholarly journals Chromatographic separation of In(III) from Cd(II) in aqueous solutions using commercial resin (Dowex 50W-X8)

2010 ◽  
Vol 8 (3) ◽  
pp. 696-701 ◽  
Author(s):  
Ayman Massoud ◽  
F. Abou El-Nour ◽  
H. Killa ◽  
U. Seddik
Keyword(s):  
Hydrochloric Acid ◽  
Aqueous Solutions ◽  
Metal Ions ◽  
Chromatographic Separation ◽  
Contact Time ◽  
Ph Value ◽  
Aqueous Media ◽  
Cadmium Ions ◽  
Initial Concentration ◽  
Commercial Resin

AbstractThis work assesses the potential of an adsorptive material, Dowex 50w-x8, for the separation of indium ions from cadmium ions in aqueous media. The adsorption behavior of Dowex 50 w-x8 for indium and cadmium ions was investigated. The effect of pH, initial concentration of metal ions, the weight of resins, and contact time on the sorption of each of the metal ions were determined. It was found that the adsorption percentage of the indium ions was more than 99% at pH 4.0. The result shows that In (III) was most strongly extracted, while Cd(II) was slightly extracted at this pH value. The recovery of In(III) and Cd(II) ions is around 98% using hydrochloric acid as the best eluent.

scholarly journals Effect of cadmium sorption by river sediments on longitudinal dispersion

2021 ◽  
Author(s):  
Mohsen Nasrabadi ◽  
Ali Mahdavi Mazdeh ◽  
Mohammad Hossein Omid
Keyword(s):  
Dispersion Coefficient ◽  
Numerical Study ◽  
River Sediments ◽  
Cadmium Concentration ◽  
Breakthrough Curves ◽  
Longitudinal Dispersion ◽  
Longitudinal Dispersion Coefficient ◽  
Bed Sediments ◽  
River Bed ◽  
Mean Diameter

Abstract This paper concerns the cadmium sorptive effects by river bed sediments on longitudinal dispersion coefficient in an open-channel flow via experimental and numerical study. For this purpose, a circular flume was used with mean diameter of 1.6 m and a width of 0.2 m. The adsorbing bed was considered as a thin layer of the sediment particles with mean diameter of 0.53 mm and three sediment concentrations of 3, 12, and 20 gr/lit. To determine the sorption parameters of the sediments, some experiments were conducted with three cadmium concentrations of 150, 460, and 770 ppb. Then, the dispersion experiments were carried out with and without the bed sediments with the same cadmium concentration as the sorption experiments. A numerical model was then developed to solve the advection-dispersion equation with considering the sorption term by river bed sediments. The longitudinal dispersion coefficients were estimated by comparing the experimental and numerical breakthrough curves. The results showed that, with increasing the sediment concentrations, the sediment sorption rate increased and the longitudinal dispersion coefficient decreased by about 38, 36 and 33 percent, respectively, for cadmium concentrations of 150, 460 and 770 ppb. In addition, by increasing the cadmium concentrations, the changes in the longitudinal dispersion coefficient are decreased. Furthermore, a relationship was developed using non-dimensional longitudinal dispersion as a function of the new parameter of sorption ratio. From a practical point of view, the results of this study demonstrated that, at the presence of riverbed sediment, the cadmium is longitudinally dispersed with more delay in comparison with no sediment at the river bed.

scholarly journals DESORPSI β-KAROTEN MINYAK KELAPA SAWIT (CRUDE PALM OIL) DARI KARBON AKTIF MENGGUNAKAN ISOPROPANOL

2017 ◽  
Vol 5 (4) ◽  
pp. 1-7
Author(s):  
Nurul Aini ◽  
Olyvia Putri Wardhani ◽  
Iriany
Keyword(s):  
Activation Energy ◽  
Activated Carbon ◽  
Isopropyl Alcohol ◽  
Desorption Kinetics ◽  
Crude Palm Oil ◽  
Desorption Process ◽  
First Order ◽  
Constant Rate ◽  
Β Carotene ◽  
Main Material

The aim of the research is to study the ability of isopropyl alcohol in the desorption of β-carotene and to obtain kinetic model and desorption isoterm which is suitable in β-carotene desorption. The main material used were isopropyl alcohol and activated carbon containing β-carotene. The variabels used in this research are desorption temperature,  activated carbon concentration  and parameter observed is concentration of β-carotene in isopropyl alcohol. In the desorption process, activated carbon which adsorp β-carotene was soaked in isopropyl alcohol. To review the desorption kinetics, this research was carried out in various temperature such as 40 oC, 50 oC, and 60 oC. In desorption isoterm process is, various mass of activated carbon was used. Desorption process will be analyzed at spesified time. This research used the first order of desorption kinetics model. The desorption constant rate obtained for 40 oC, 50 oC, and 60 oC are 0,013, 0,014, and 0,036 minute-1 with activation energy is 0,226 kkal/mol. The maximum desorption percentage obtain is 41,94 %. The desorption isoterm model which fit with the β-carotene desorption was Langmuir isoterm model with constanta value 1,2077 L/mg and -0,2218.

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