Adsorption : Dynamic And Dynamic Adsorption Process Design And Optimization Of Operating Conditions

Adsorption chromatography occurs when “one substance form[s] some sort of bonds to the surface of another one”, creating intermolecular forces between the two substances (Chemguide). For thin layer chromatography, the components of the mixture are adsorbed onto the stationary phase that covers the plate (Chemguide). The more polar a substance is, the more strongly adsorbed it is (Chemguide) and the strong intermolecular forces then result in a slower rate of migration with respect to the moving phase. As the solvent touches the TLC plate, the solute (mixture) is allowed to move up the TLC plate

Adsorption area (peak) are present at a wavelength of 1454.33 cm-1 in the ACS adsorbent without activation identifies alkanes in the C-H stretching group, where physical activation and chemical activation eliminates a large amount of hydrogen from the adsorbent. The stretching group of C=O at a wavelength of 1707 cm-1 indicate that physical and chemical activation cannot detach ester completely from the adsorbent surface. Overall, there are a number of active sites with hydroxyl and carboxylate functional groups on the surface of the ACS adsorbent that able to adsorb metal ions Cd (II).

The eluting solvent passed down the column by the gravity and an equilibrium was established between the solute absorbed by the absorbent (silica gel in this experiment) and the eluting solving flowing down. Since the components in the sample had different polarity and they interacted with the stationary phase and the mobile phase differently, the components would be carried by the solvent to a different extent and a separation of the components could be achieved.

Thin-layer chromatography (TLC) consists of a TLC plate (stationary phase) that is partially immersed in a solution (mobile phase) to separate compounds on it, based on polarity. When an unknown compound, with distinct polar components, is placed on the TLC plate, the components with low polarity will have traveled the farthest from the start line it was set on. A compound with low polarity also has a large Rf value () on a TLC plate. The Rf value is a ratio that depicts how much a compound interacted with the TLC plate. However, the compounds from experiment 5 were separated with an adsorption chromatography column.

Zhang et al23 (2013) reported the removal of tetrabromobisphenol A (TBBPA) from aqueous solution by GO. The effects of contact time, pH, and temperature, and the presence of coexisting anions as well as humic acid, were studied through batch experiments. The adsorption capacity decreased with an increase in temperature as well as solution pH. The presence of coexisting anions such as NO-3 SO4 -2 −, HPO4 -2 and HCO 3 2- reduced TBBPA adsorption in the order NO3 - < SO4 2- < HPO4 2- < HCO3 2-The presence of humic acid also significantly reduced the adsorption of TBBPA onto GO. The adsorption reaction followed the pseudo-second-order kinetics, while the adsorption isotherm was well described by the Langmuir model with a maximum adsorption capacity of 115.77 mg g−1 at 298 K. Thermodynamic studies indicated that the adsorption of TBBPA onto GO was feasible and spontaneous at all temperatures and was exothermic in nature. Both π–π stacking interactions and hydrogen bonding were proposed to be responsible for the adsorption of TBBPA by GO.

Weight data and images showing the physical appearance of the BPs are shown in Figure 3 and 4, respectively. Acetone-cleaned AD BPs lost approximately 26, 48, and 32 % of their weight, whereas methanol-cleaned AD BPs decreased their weight by around 29, 40, and 34 % at 300 ˚C for 90 min, 350 ˚C for 60 min, and 300 ˚C for 120 min, respectively. HiPco BPs lost about 22, 5, and 1 % at 350 ˚C for 30 min, 300 ˚C for 30 min, and 250 ˚C for 30 min, respectively. However, when we recalculated the weight change from the theoretical weight of AD BPs considering the surfactant effect, + 5, - 25, and - 2 % weight of acetone-cleaned AD BP were changed after HT at the first (300 ˚C - 90 min), second (350 ˚C - 60 min), and third (300 ˚C - 120 min) conditions while there were + 5, - 13, and 0 % changes in weight for methanol-cleaned AD BPs. As a result, at the first and third conditions, the weight change of AD BPs weight change was minimal and while for HiPco BPs weight change was minimal at the second and the third conditions.

Both charcoal and bentonite clay are currently used to remove PAHs from water sources. This experiment was conducted to determine which material was the more effective sequestering agent of PAHs through the use of Procion Red Dye. A spectrometer was used to create a calibration curve to which the absorption of both the charcoal and clay could be compared. Ultimately, the charcoal proved to be the most effective PAH adsorbent.

I may revisit longer experiments for measuring equilibrium, however I think for purposes of time and this study, it will be best to run short experiments of that length. I can compute the rate of each and plot the ‘log (k)’ with respect to ‘log ([Methylene Blue]0)’. The slope should give us the order of methylene blue adsorption to the surface. Any differences amongst the four surfaces should be apparent. It may also lead better insight into where we are binding.

In this experiment, the Ksp for calcium sulfate dihydrate, CaSO4·2H2O, by titrating 4 times a calcium sulfate dihydrate solution with diprotic EDTA, H2(EDTA)2-. For each trial we found the Ksp by means of molarities and activities. The results for the Ksp using only molarities was very different than the Ksp using activities. The average Ksp using molarity only was 2.26 x 10-4 and the average Ksp using activity turned out to be 2.31 x 10-5. The actual Ksp however, is 3.14 x 10-5. A percent error of 26.6 % was calculated.

Chromatography is a technique used to separate a mixture of compounds for analytical or preparative purposes. In liquid chromatography, the mixture of compounds is dissolved in a liquid mobile phase and then travels through a stationary phase, which acts as the adsorbent. Solute molecules interact with the stationary phase through adsorption and desorption. A compound which has stronger interactions with the stationary phase will move slower than a compound with weaker interaction with the stationary phase. The components of a mixture are separated based on their differences in mobility.

The pH of the media is considered to be one of the most important environmental factors affecting the biosorption process. Moreover, it affects the solubility of metals and ionization state of functional groups which includes carboxyl, phosphate and amino groups of cell wall (Wang and Sun 2013). The effect of pH on the biosorption of aluminium is presented in Fig. 2a. Results show that the amount of aluminium ion uptake increased (10 - 92 mg/L) by rise in pH values (2.0 – 6.0) and the maximum removal efficiency was observed at pH 6. At low pH (less than 4.0) heavy metal removal was inhibited, as a result of positive charge density on metal binding due to a high concentration of protons in solution. With an increase in pH, the negative charge density on the cell surface increases due to deprotonation of the metal binding sites and thus increases biosorption (Say et al. 2001). At alkaline pH, more Al appears in a

Methods used to separate miscible solvents include thin layer chromatography (TLC) as well as column chromatography. A method used to separate a mixture of miscible solvents is column chromatography, which is used to purify and separate compounds. The particular speed of the solvents used in the experiment depended upon the properties, being polar or nonpolar, as well as the properties of the prepared column (INSERT SOURCE HERE). With column chromatography, there are two phases that include mobile and stationary phases. In the experiment performed, the glass column used was first packed with a piece of cotton followed by a layer of sand in order to keep the silica gel in place and also to prevent the gel from flowing out of the tube when the particular solvent was added. Based upon whether the

Batch experiments were designed to investigate the efficiency of fluoride removal with varying conditions of extraction. 100 ml of ground water from one of the samples was pipette out into a 250ml conical flask and to it, weighed quantity of the prepared active carbon adsorbent was added, pH (=7) was adjusted and the solution was stirred for desired period at 200 rpm on a mechanical shaker at room temperature 30±10C. Then the solution was filtered through Whatman No: 42filter paper. The fluoride concentration in the sample after de-fluoridation was determined by SPADNS method using U.V-Visible Spectrophometer (Model No: Elico U.V-2600) as described in the “Standard Methods for the Examination of Water and Waste water18” at λ max 570 nm. The same procedure has been adopted for the experiments carried out with different active carbon adsorbents: NVNC, NSOC, NAbIC and NAcIC at the optimum conditions of pH (=7), contact time (50min for both NVNC and NSOC and 60 min for both NAbIC and NAcIC) and adsorbent dosage. It has been observed that the amount of active carbons required for defluoridation of l m3 (1000 liters) water are: 2.61 kg for NVNC, 3.09 for NSOC, 3.61 for NAbIC and 3.72 kg for NAcIC.

Gangue is one of the largest accumulating solid, and is particularly rich in pyrite. Therefore, pyrite recovery from gangue is not only significant for the environmental protection, but also for the development and production of chemicals. The dry separation methods, leading to the decreased waste and cost effectiveness, have received significant attention of many scholars. In this study, the vibration energy was introduced to promote the separation of particles. The interactions and effect of comparison of the gas velocity, vibration intensity, and bed height were investigated. Moreover, the sulfur migration for pyrite recovery from the gangue has been studied by several analytical techniques. The results show that the segregation efficiency was directly related to the interaction between various factors. After the separation, the sulfur content of the concentrates of -6+3, -3+1, and -1+0.5 mm was 37.94, 35.43, and 30.61%, respectively. The sulfur segregation’s standard deviation (SSSD) was >0.70, achieving a satisfactory separation efficiency, indicating that pyrite was the foremost material in the concentrate, and S and Fe migrated in the form of pyrite during the separation process, indicating that pyrite could be effectively enriched by the dry method of vibration fluidized bed after the separation.

IN PARTIAL FULFILLMENT OF THE REQUIREMENT FOR THE AWARD OF MASTER OF SCIENCE (ENVIRONMENTAL CHEMISTRY AND POLLUTION CONTROL)