2.6. Batch adsorption experiments
2.6.1. Adsorption experiments
The adsorption studies were performed in batch experiments by agitating definite amounts of the studied resin with Hg2+ aqueous solution with predetermined concentrations at varying pH values, temperatures and for deferent time intervals. For pH studies; 0.05g of the studied resin was equilibrated with 50mL 100mg/L Hg2+ solution for 3h at 300C. HCl/KCl was utilized to adjust the pH range 1-3, CH3COOH/CH3COONa was used for pH 4 and 5. For temperature effect studies, 0.05g of the resin were equilibrated with 50mL Hg2+ aqueous solution with initial concentration 50mg/L and pH 5 for 3h at 150rpm in temperature range 20-40. The kinetic studies were carried out by shacking 0.5g of the
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Selectivity coefficient (βHg2+/Mn+) was computed using Eq. (3) in order to evaluate the selectivities of both ion-imprinted Hg-PMTF and non-imprinted NI-PMTF for Hg2+ ions compared to other interferring metal ions [26]. βHg2+/Mn+ = D Hg2+/DMn+ (3) where D Hg2+ and DMn+ are the distribution coefficient of the Hg2+ ions and the other interfering metal ions, respectively, which can be calculated according to Eq. (4).
D = [(Ci-Ce)/Ce]V/W (4)
The potential of the ion-imprinting process in improvement of Hg2+ selectivity can be evaluated using relative selectivity coefficient βr (Eq. (5)) [27, 28]. βr = βimprint / βnon-imprint (5) where βimprint and βnon-imprint are the selectivity coefficients related to both Hg-PMTF and NI-PMTF resins, respectively.
2.8. Desorption and
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The main diagnostic peaks that are related to the ligand active groups and which are expected to display marked shifts or changes after coordination with Hg(II) are summarized in Table 2. As previously reported [29, 30], thiosemicarbazide and thiourea derivatives, which contain thioamide (-NH-C=S) moiety are known to display thione–thiol tautomerism in solution. The presence of v/δ(C=S) characteristic peaks at approximately 1300, 870 cm-1, absence of v/δ(C-S) peaks at about 1150, 650 cm-1 in addition to the absence of the diagnostic (S-H) peak at 2350 cm-1 and presence of only one peak at 1660 cm-1 correspond to the triazine C=N bond, revealed that thione form is the dominant one in solid state. After coordination with Hg2+, the spectrum of the complex showed an appearance of two peaks at 1150 and 650 cm-1, which are related to both stretching and bending vibrations of C-S bond, in addition a new peak at about 1665 cm-1correspond to C=N was also observed. These observations indicated that thion- thiol transformation had been performed during coordination with Hg2+. Also, the absence of S-H characteristic peak at about 2350 cm-1, gives and evidence for the deprotonation of the thiol (S-H). Moreover, the obvious shift of the triazine C=N peak at 1630 cm-1, confirms involvement of triazine
If more than one complex is formed at different pH values, their existence can be decided by this type of study. The pH, at which the absorption due to a particular complex species is far greater than that of metal ion and or the ligand alone, is selected for the study of that species. As the complex formation is the function of pH; it should be kept constant for particular system. Similarly, ionic strength is maintained constant throughout by adding an appropriate volume of sodium perchlorate. pH can be remained constant by using suitable buffer, provided the buffer does not interfere with the complex formation at wavelength where complex species show maximum
Discussion and Conclusions: Interpreting these results have concluded that relative reactivity of these three anilines in order of most reactive to least reactive go; Aniline > Anisole > Acetanilide. Aniline, has an NH2 , the most active substituent , and adds to any ortho/para position available on the ring. This data is confirmed with the product obtained, (2,4,6 tribromoaniline, mp of 108-110 C). As for anisole, it has a strongly activating group attached, OMe an alkoxy group, and it added in two of the three available spots, both ortho. The results conclude: (2,4-Dibromoanisol mp 55-58 C ). Acetanilide has a strong activating group attached, acylamino group, but this group is large and the ortho positions are somewhat hindered so the majority of the product obtained added at the para position, results conclude: (p-bromoacetanilide mp 160-165 C). Since all the substituents attached to the aromatic rings were activators the only products able to be obtained were ortho/para products.
Denture teeth can be made of acrylic poly(methyl methacrylate) (PMMA) or composite resins. PMMA is a polymer - a material made the from joining of methyl methacrylate monomers. Properties of PMMA include resistance to abrasion, chemical stability and a high boiling point. (Jun Shen et al. 2011). However, weak flexure and impact strength of PMMA are of concern as they account for denture failure. (Bolayir G, Boztug A and Soygun K. 2013). Composite denture teeth are made of a three distinct phases - filler, matrix and coupling agents. Out of the types of composite teeth available, nano-filled composite teeth are preferred. Composite teeth have a PMMA coating around the tooth and a high content of filler particles. This gives them strength, higher resistance to forces than acrylic teeth and provides compete polymerization due to the PMMA coating. (Anusavice, K. J., Phillips, R. W., Shen, C., & Rawls, H. R, 2012). If the interface between the PMMA denture base and PMMA or composite teeth was weak, the denture will not be able to sustain occlusal forces, making the base-teeth interface, an entity of significance.
The same procedure was done using 10ml of CV and 20ml of sodium hydroxide, both separately diluted to 50ml and added in a large beaker. The absorbance was recorded. In the last trial, 10ml of CV, 10ml of NaOH were diluted to 50ml. Before adding the two mixtures, 1ml of soap was added to the NaOH solution and then poured into a large beaker, along with the CV. Absorbance was recorded and the materials
Chabay, Ruth; Kean, Elizabeth; Jones, Loretta; Rogers, Elizabeth; Smith, Stanley; Stovall, Iris. Fundamentals of Chemistry. University of Wisconsin-Madison, 2000. Web. March 17, 2014.
Due to stringent regulations regarding the emission of volatile organic compounds, there is a demand to develop fast setting solvent free resins. Light cured materials have many advantages over conventional chemically cured adhesives, including consistent handling characteristics, single paste application, and easy removal of excess material and extended working time.1 UV-curable adhesives appear to be ideal candidates since such liquid formulations contain no organic solvents and are readily transformed into solids by a short exposure to UV-radiation at ambient temperature. This feature, together with the resulting low consumption of energy and the high performance of the UV-cured materials, explains the increasing use of this environment-friendly
This experiments were carried out to investigate the potential of banana peel as adsorbent for the removal of heavy metal. For this experiment, the bisorbent is untreated and less remove of heavy metal than treated biosorbent.
Procedure: Hirko, R. Chemistry 112L General Chemistry I Laboratory, Ninth Edition; bluedoor: Minneapolis, 2015; Experiment 1.
...ku MN, Neme AL, Linger JB, Pink FE, Walker S. Effect of pre-heating resin composite on restoration microleakage. Oper Dent. 2008; 33(1);72-8. YELLOW
11. Bagis YH, Baltacioglu IH, Kahyaogullari S. Comparing Microleakage and the Layering Methods of Silorane-based Resin Composite in Wide Class II MOD Cavities. Oper Dent. 2009; 34(5): 578-585.
Therefore, plastic packages are coded to indicate the type of resin used to make them. The
The first qualitative analysis to identify ions is the flame test. The flame test is a qualitative analysis that allows us to identify different metal ions in a solution. When metal ions are heated in a flame, they turn a unique colour, and when examining the colour of the flame, one can try to identify the ions present in the solution. For example, when lithium ions are heated they turn crimson red, but when potassium ions are heated they turn lavender. One problem with flame tests is that they are very sensitive, so when conducting an experiment, it is advised to only use tiny samples to increase the test’s accuracy. An extremely useful tool when conducting flame tests is the Bunsen burner. The Bunsen burner was named for Robert Wilhelm Eberhard Bunsen (1811-1899), a German chemist who contributed to its invention only in a minor way. The Bunsen burner produces a clean, hot flame and is used along with a wire loop (usually platinum or an alloy of nickel and chromium) to perform flame tests. When using aqueous solutions, one must simply dip the wire into the solution and then place it into the flame. When using solid solutions, one must first combine the solution with hydrochloric acid or nitric acid,...
Aim: To perform a comparative test on which metal is the most reactive with acids.
Silver nanoparticles synthesized solution was centrifuged at 15000 rpm for fifteen minutes to obtain the SNP pellets and redispersed with 1ml of distilled water and allowed to dry to obtain dry powder to enable the FTIR and SEM analysis. odered Silver nanoparticles were subjected to FTIR analysis to find the possible interaction of silver and
The characteristics of chitosan that may affect its sorption properties should be explain in order to understand the values and limitations of the chitosan used in this experiment. These include the degree of deacetylation, the structural condition and the crystallinity.